Ecology and nature conservation: Environmental risks in the production of building materials. Environmental problems of polymer production Environmental problems of production and use of building materials

Diagram of the impact of the building materials industry (BCI) on the environment.

In the conditions of intensive development of industry, the construction of large and small cities, the question arises of preventing the negative impact of human activity on the environment.

A major role in solving this problem is assigned to the construction industry, in particular, the industry of building materials. The impact of the building materials industry on the environment is diverse and occurs at all stages, from the extraction of raw materials to the operation of buildings and structures, i.e. throughout the life cycle. Many construction industry enterprises are sources of environmental pollution (air and water basins, the Earth's surface) with cement asbestos, expanded clay and other types of dust; flue gases of thermal installations; sewage, various oils and emulsions; fuels and lubricants; waste and defective products.

The extraction of raw materials and processing into building materials and products should be carried out using resource-saving technologies that should not have a negative impact on the environment. Therefore, a large place in the construction industry is given to the creation of low-waste and waste-free technologies that allow solving not only the problem of protecting the environment from technogenic pollution, but also the problem of the rational use of natural resources.

Waste-free technology is the main method of production, in which raw materials and energy are used more rationally and comprehensively in the cycle of raw materials - production, consumption - secondary raw materials, in such a way that any impact on the environment does not disrupt its normal functioning.

One of the forms of non-waste technology is the processing and disposal of waste from various industries, incl. and own.

Waste management is a socio-economic problem. The removal and dumping of industrial waste means the loss of part of the social labor and funds spent on production, as well as on protecting the environment from pollution.

Industrial waste pollutes the water basin and soil. At the same time, many types of waste are valuable raw materials for the production of building materials.

Thus, the main directions of environmental protection in the building materials industry are as follows:

the use of secondary mineral resources of many industries (large-tonnage waste from energy, metallurgy, chemistry, etc.), as well as their own;

rational use of fuel and energy resources with the choice of the most efficient and least environmentally polluting;

Transition of enterprises to low- and non-waste production;

Rational water consumption with the development and implementation of technologies that provide for minimal water consumption, a closed water supply cycle, and an efficient wastewater treatment system.

Engineering for environmental safety in the construction industry

Ensuring environmental safety in the construction industry is carried out with the help of environmental protection measures and the rational use of resources consumed in the manufacture of building materials.

To obtain objective information about the state and level of pollution of various environmental objects (air, water and soil), it is necessary to use reliable methods of analysis. The effectiveness of any method is evaluated by a set of indicators: selectivity and accuracy of determination, reproducibility of the obtained materials, detection limits of the element and analysis speed.

One of the most important measures to ensure effective control of the state of the environment is the inventory of all emissions and discharges that pollute the atmosphere, water and soil.

Monitoring the state of the environment is carried out using the analysis of air, water and soil. In addition, in order to improve the environment and prevent its pollution, measures are being developed aimed at the production of environmentally friendly building materials, products and structures using progressive environmentally friendly technologies.

One of the directions of stabilization and subsequent improvement of the state of the environment is the creation of a system of ecological certification of enterprises in the construction industry. The methodological basis for certification is GOST 17.00.04-90 “Passport of an industrial enterprise. Basic Provisions". The FZRF “On Technical Regulation” is also aimed at this.

Often ordering repairs at home or in the office, we think about how long it will serve us, whether the builders will make a marriage, whether the design will be harmonious. And very rarely we ask ourselves, how will the use of certain building and finishing materials in the production of repairs or decoration affect health? They look fashionable and easy to clean, but they undermine our health. And sometimes they do it unnoticed. Some synthetic materials emit vapors into the surrounding space, consisting of various chemicals: phenol, formaldehyde, toluene, benzene, and the like, which contribute to the emergence of a whole bunch of chronic diseases.

It so happened that in our country, builders rarely think about where this or that material comes from and how it affects human health. Majority construction organizations do not conduct environmental management in relation to construction and installation works GOST R ISO 14001-98 (ISO 14001), some do not even know about such standards.

Environmentally friendly materials, of course, cost more! Therefore, a situation arises that builders are chasing cheap and often low-quality materials from an environmental point of view. Builders are forced to use such materials at municipal construction sites, since officials usually follow the widespread principle “the cheaper the better for the state” when holding tenders, tenders and auctions for construction and repair work, they do not take into account what materials will be used to perform the work. And this means that in schools, kindergartens, hospitals, materials are used, which will be discussed below.

From an environmental point of view, building materials can be divided into harmonious and inharmonious. Inharmonious materials are called those materials, the presence of which has a negative impact on a person, and sometimes causes direct harm to health. Harmonious materials can be considered those that are widely distributed in nature. There is a persistent pattern between the prevalence of the material and its harmfulness and toxicity. For example: water, earth (soil) are not toxic, and such relatively rare elements as lead, mercury, cadmium are very dangerous for living organisms. According to this pattern, for the construction of a dwelling it is better to use raw materials that are widely used. In mild, humid climates in wooded areas, wood is, of course, the best material. In hot dry areas - soil and clay, in cold mountainous areas the most common building material is stone. Before the super-development of industry, builders naturally chose widespread, harmonious materials. Development technology has greatly expanded the range of materials and structures. The industrial approach to construction has led to the widespread use of expensive and artificial building materials. Now rarely anyone turns to traditional materials, if it is possible to use modern ones. However, it is still worth considering not only the aesthetic and practical side, it is necessary to pay attention to the environmental safety of the material. Portland cement at first glance seems like an ideal building material. Cured concrete turns out to be an extremely strong, durable, dense, heavy material, which is better not to be used for walls and ceilings of an individual house. The set cement mortar does not breathe, does not transmit atmospheric electrical waves, deflects or amplifies electromagnetic waves.

Reinforced concrete (metal-reinforced concrete) has even more undesirable characteristics for a home. The rods and meshes of the reinforcement of the reinforced concrete building shield electromagnetic radiation. Reinforced concrete "presses" on a person, in such structures people get tired faster. In part, this may be due to the fact that during the firing process, cement absorbs toxic substances, and rocks with an increased level of radiation serve as a filler for heavy concrete, structures cease to pass air, and an uncomfortable microclimate is established in the room.

The aggregate of the concrete mixture significantly affects its environmental characteristics. Heavy crushed granite, lava rocks with high density, in addition to high natural radiation, do not have pores, do not breathe, which (as mentioned above) is undesirable for wall structures).

Synthetic materials and plastics are increasingly used in residential construction, but for the most part they are not environmentally friendly materials. The use of metal in individual construction should be minimized, since metal structures distort the natural magnetic background and cosmic radiation.

Metallic paints are a classic example of a hazardous building material. As the solvent dries, the particles of the paint layer enter the air of the room, settling on objects, food, etc. In the 60s, there were cases of poisoning of children whose toys were coated with paints containing mercury and lead. Switching to alkyd-based paints eliminates problems heavy metals, but the question arises about the environmental friendliness of other chemical additives.

Synthetic paints give off a strong odor when dry. Drying occurs not only in the first hours and days, but also over a number of years. For example, one of the components of modern paints - polyvinyl chloride - decomposes at normal room temperature in contact with air and, especially in sunlight. Hydrochloride evaporates into the air, which, when inhaled, creates an acidic environment. Polyvinyl chloride easily penetrates the skin and has a harmful effect on the blood and liver. Vinyl tiles and linoleums emit toxic gases into the air as new layers of material are constantly deposited on the surface during the evaporation process. Polyurethane foam is an excellent thermal insulation material, but it turns out that its effect on the skin and eyes (when touched or in contact with dust) causes more than just irritation. When inhaled, particles of this material combine with protein in the lungs and over time change its structure, resulting in emphysema. Polyvinyl floor and wall coverings, synthetic paints are materials hazardous to health and the environment, their use in the home should be limited.

Dry plaster and glued wood are heavily saturated with synthetic adhesives. Polymers are used to enhance their water resistance and as adhesives. During the production of plastic, formaldehyde, phenolic and other chemical compounds remain in the material and gradually disappear, which have an adverse effect on the respiratory, blood and immune systems of a person in a room finished with synthetic materials. Static electricity accumulated on plastic surfaces not only affects the heart and nerves, but also increases the penetration of toxic synthetic compounds and their accumulation in the form of dust. Dust becomes a haven for germs. Synthetic plastic coatings contribute to the occurrence of pulmonary diseases (in particular, electrical pneumonia). In the spring, with high humidity, a person walking on a synthetic floor can generate an electrical charge of thousands of volts per 1 m3.

You should be very careful when choosing synthetic materials for your home. Plastic in the kitchen makes cleaning easier, but deteriorates from heat, acids and mechanical damage. Wall materials are resistant to decay and insects, but emit unpleasant gases when heated. In general, the use of organic, environmentally friendly materials of natural origin should be sought.

Unfortunately, there is very little information about the ecology of building and finishing materials. In addition, we want to make repairs quickly and cheaply, and manufacturers and sellers - to sell a lot and expensively, forgetting to talk about possible negative manifestations, show the product only from the good side. Of course, all finishing materials have an environmental certificate. But the fact is that the norms are indicated for one type of furniture or finishing material. There are a good dozen of them in the room. And the accumulating effect of the smallest particles of toxic substances from furniture and various finishing materials is almost impossible to calculate and cannot be regulated by any hygiene standards. So it turns out that each individual roll of wallpaper or linoleum has a legal certificate, and together they will create an atmosphere that negatively affects health. Of course, not all modern building and finishing materials are dangerous. You just need to know where and which of them can be used in order to minimize possible problems.

Danger number 1. Formaldehyde
Formaldehyde gas is the most toxic compound that is released from finishing materials.

Cause: Formaldehyde is found in the resin used to make chipboard (particleboard), fibreboard (hardboard), plywood (FRP), mastics, plasticizers, putties, and steel mold lubricants.

Possible consequences: Formaldehyde irritates mucous membranes and skin, has carcinogenic activity. Prolonged inhalation of formaldehyde vapors, especially in the warm season, can provoke the development of various skin diseases, visual impairment and respiratory diseases.

Alternative: When using panels made of chipboard, fiberboard, FRP in a children's room, it is necessary to pay attention to the presence of a laminating coating that prevents the release of formaldehyde into the environment. When buying panels, it is advisable to give preference to domestic products. The fact is that the Russian maximum permissible standards for formaldehyde are 10 times tougher than European ones. A good alternative to chipboard, fiberboard and FRP boards is MDF. The abbreviation MDF is a tracing paper from English - MDF - Medium Density Fiberboard (medium density fiberboard). When wood is heated, lignin is released, which acts as a binding element. It should be noted that the production of MDF panels does not use resins harmful to humans, so they can be used to decorate any premises, including children's rooms. In addition, they are distinguished from other finishing materials by a high level of sound absorption, sound and heat insulation.

Danger number 2. Phenol
Reason: The use of varnishes, paints and linoleum leads to a 10-fold excess of the maximum permissible concentration of phenol. Especially dangerous is the use of indoor varnishes and paints intended only for outdoor use, permitted for outdoor use.

Possible consequences: Damage to the kidneys, liver, changes in blood composition.

Alternative: For painting work, choose natural-based varnishes and paints. Of modern materials, alkyd or polyester paints have won a good reputation among hygienists, environmentalists and builders. They possess a high degree adhesion to metal and any kind of surfaces on a mineral and organic basis (wood, brick, concrete, fiberboard, plaster). During application and subsequent polymerization, such paints do not emit a toxic odor or highly toxic substances and have a short drying time compared to oil paints. Also, they are not as aggressive to human health as organic - water-based or, which is the same thing, water-dispersed paints. The service life of such coatings is determined primarily by the quality of the binder. At present, PVA and whitewash "talkers" have been replaced by modern paints, where the main components are latex and acrylic copolymers. Polyacrylate dispersions give the necessary wear resistance and hardness to the surface film formed during drying, and the presence of latex imparts the necessary elasticity to the system. But putting linoleum in a nursery is undesirable. Of course, the floor covered with linoleum is easy to use. But it is much safer to replace it with laminate, parquet or wood flooring.

Danger number 3. radioactive radiation
Quite often, in residential premises, an excess of radiation standards for RADON-222, the most dangerous radioactive inert gas for human health, is found.

Cause: Some building structures may include natural materials with radionuclide content far in excess of current radiation safety standards. Quite often, when repairing houses, a mixture of concrete and crushed granite is used, which has a high radiation background. In addition, some types of phosphorescent wallpaper (with elements glowing in the dark) that are currently common can be the cause of excess radioactive radiation.

Possible consequences: Oncological diseases especially at risk of developing lung cancer.

Alternative: A mixture of concrete and crushed granite is often used by builders when restoring walls and floors. This is one of the cheapest materials. But in order not to pay for cheap health repairs later, it is advisable to use a variety of putties, plasters and hinged panels to restore walls and floors. And before sticking wallpaper and laying floors, it is desirable to cover all cemented surfaces with a thin layer of putty, which will reduce possible radiation radiation. Also, if possible, get rid of the dense reinforcing cage, which changes the level of natural radiation in the room. As for the wallpaper, high-quality phosphorescent wallpaper must be tested for the presence of radiation. Therefore, in large specialized stores, the risk of buying wallpaper - "pests" is minimized. But in various markets, quite “dangerous” rolls often come across. It is impossible to determine the quality and presence of background radiation on wallpaper without special instruments. Therefore, for your own safety, purchase finishing materials only in large specialized stores.

Danger number 4. Styrene molecules
Reason: The main sources of styrene release are thermal insulation foams, facing plastics, linoleum, as well as varnishes, paints and adhesives. In addition, the concentration of styrene in the air significantly increases the decoration of walls and ceilings with dry clapboard.

Possible consequences: Irritation of mucous membranes, eyes, headache, nausea, vasospasm.

Alternative: To reduce the concentration of styrene molecules in the air, absolute vapor barrier of the walls from the side of the premises is necessary. A good way to vapor barrier is to use vinyl wallpaper. To ensure thermal insulation, use only natural-based materials. Styrofoam is not recommended for use in a nursery. It is also undesirable to install suspended ceilings made of foam and plastic panels in the room where the baby lives. It is much safer to paint the ceiling with water-based (water-based) paint or paste over with paper wallpaper. In addition, try to minimize the amount of building material used. From the fact that you paint the battery with three layers of paint, beauty will not increase, and the concentration of styrene molecules in the air will increase significantly.

Danger number 5. Aerosols of heavy metals
The daily concentrations of many metals indoors significantly exceed their content in the atmospheric air. For lead, this difference is 2.3 times, cadmium - 3.2 times, chromium - 10%, copper - 29%.

Reason: Some types of wallpaper and carpets accumulate a huge amount of heavy metal aerosols. In addition, concrete, cement, putties and other materials with the addition of industrial waste are distinguished by a high content of heavy metals.

Possible consequences: Diseases of the cardiovascular system, liver, kidneys and allergic reactions.

Alternative: Try to redecorate the room at least once every five years with the replacement of wallpaper and baseboards. Heavy metal aerosols have the unpleasant property of accumulating over time. Therefore, the more often you change wallpaper and skirting boards, the cleaner the air in the room will be. Just before proceeding with the repair, carefully remove old materials (wallpaper, plaster). Some builders prefer to glue new wallpaper on top of old ones, explaining that this way they will stick better. In fact, they are driven by ordinary laziness, and not by the desire to make high-quality repairs. Well-prepared walls will not only provide cleaner air in the room, but the wallpaper on them will also hold up well.

In the nursery, it is undesirable to put carpet under the baseboard. You should always be able to wipe the floor underneath.

Danger number 6. PVC
PVC products are made from polyvinyl chloride, a dangerous poison that can damage the nervous system and cause cancer. The release of vinyl chloride into the environment increases even with slight heating.

Unfortunately, PVC is a very common plastic. You can find it everywhere. In an apartment, it is most often found in the form of linoleum (excluding some expensive brands), vinyl wallpaper, plastic window frames, plastic toys (from dolls to children's dental rings). Also made from pvc different kinds packaging, including food products: bottles, bags, etc.

When buying something made of PVC, remember:
- To make PVC elastic, so-called plasticizers are often added to it - phthalates or phthalate esters, the entry of which into the body can cause damage to the liver and kidneys, a decrease in the protective properties of the body, infertility, cancer. PVC may also contain other hazardous substances: cadmium, chromium, lead, formaldehyde.

- PVC is especially dangerous when burned. It is known that when burning 1 kilogram of PVC, up to 50 milligrams of dioxins are formed. This is quite enough for the development of cancerous tumors in 50,000 laboratory animals.

— There are no safe technologies for PVC processing. It is virtually non-recyclable and goes to incinerators (ITW) or landfills. Dioxins, relentlessly produced by incinerators, are distributed over hundreds and thousands of kilometers.

- The production of one window from PVC leads to the formation of about 20 grams of toxic waste. And the renovation of the entire apartment using materials made of PVC entails the formation of 1 kg (!) of toxic waste.

“In one year, PVC plants emit several thousand tons of vinyl chloride into the atmosphere, endangering the health of workers and residents of nearby communities.

- At PVC production chlorine is also used, therefore, during its manufacture and disposal, a large amount of dioxins, highly toxic substances that cause cancer and undermine immunity, are released into the environment.

How to identify a PVC product?
In civilized countries, PVC goods are usually marked with a special marking - the number "3" surrounded by arrows. Some manufacturers just write PVC or Vinyl. In Russia, unfortunately, plastic goods are practically not marked. However, PVC can be distinguished by a number of features:
when the package is bent, a white stripe appears on the bend line;
PVC bottles are bluish or blue in color;
Another distinguishing feature of PVC containers is the seam on the bottom of the bottle with two symmetrical influxes.
Control and certification.
Only a system of hygienic and environmental certification can protect the average consumer from environmentally hazardous and low-quality construction products, which in our country began to fully operate only in recent years. Now in Russia it is legally prohibited to use materials in construction that do not have a special hygienic certificate. These materials include facing slabs made of natural stone, ceramic granite, slag concrete, crushed stone, sand, cement, brick and many others.
Hygienic assessment of products includes:
determination of the possible adverse effects of products on human health;
establishment of permissible areas and conditions for the use of products;
formation of requirements for the processes of production, storage, transportation, utilization of products that ensure safety for humans.

The hygienic certificate is issued by the State Sanitary and Epidemiological Surveillance Service.
When purchasing any building or finishing material, the buyer should ask the seller if the seller has a hygiene certificate for the product. Two, at first glance, completely identical rolls of linoleum or wallpaper, made by different manufacturers with slight changes in technology, can differ in the level of release of toxic substances by several tens of times. And only competent organizations are able to solve the issue of their environmental safety.

Biopositivity of materials
Building materials have a great influence on the formation of the quality of the near environment of life. The concept of environmental friendliness of building materials is broader than their environmental friendliness.

Completely ecological (biopositive) materials include building materials from renewable natural resources that do not have a negative effect on humans (and even have a positive impact on human health), do not pollute the environment during their manufacture, require minimal energy consumption in the manufacturing process, are completely recyclable or decomposing after performing their functions like materials of living nature. Very few natural materials meet all these requirements: wood (and other plant materials - bamboo, reed, straw, etc.), wool, felt, leather, cork, coral sand and stones, natural silk and cotton, natural drying oil, natural rubber, natural adhesives, etc.

Conditionally environmentally friendly building materials can be considered materials obtained from minerals widely represented in the earth's crust, or almost completely recyclable materials (therefore, they experience a slight loss and, moreover, allow saving up to 80 ... 90% of energy for their production). These include products made of clay, glass, aluminum. The rest of the materials are not environmentally friendly, although they are used in construction (this includes plastic-based artificial materials, products that require significant energy consumption in their manufacture, etc.).

Eco-friendly materials are those materials that satisfy the principles of environmental friendliness: they use renewable resources in their manufacture, they are amenable to self-degradation after performing functions without polluting the environment; as partially biopositive, fully recyclable materials can be considered, made from a mineral widely represented in the earth's crust (aluminum, silicon). Improvement of materials in the direction of their biopositivity will apparently be carried out both in accordance with modern trends (the use of recycled materials, reducing material consumption, increasing their durability, etc.), and in the direction of a more complete use of natural reproducible materials, the creation of new materials with desired properties and biosimilar materials that could be powered by energy.

The factors affecting the environmental safety of a person's home include the quality of building materials - what the house is made of. The functional purpose of a residential building is to meet the needs of a person in housing. Depending on the type of material from which the main load-bearing elements of residential buildings are made and their constructive solution, buildings are combined into the following groups:

Stone, especially capital, brick walls with a thickness of 2.5-3.5 bricks or brick with a reinforced concrete or metal frame, reinforced concrete and concrete floors;
The walls are large-block, the floors are reinforced concrete;
The walls are brick with a thickness of 1.5-2.5 bricks. Reinforced concrete, concrete or wood floors;
Walls - large-panel, reinforced concrete floors;
Lightweight masonry walls made of bricks, monolithic concrete, cinder concrete, reinforced concrete or concrete ceilings;
Large-block or lightweight masonry walls made of brick, monolithic concrete, cinder concrete, small cinder blocks, shell rock, wooden floors;
The walls and ceilings are mixed, wooden chopped or block-beamed;
Raw, prefabricated panel, frame-fill, etc.

It has been established that metals are the least desirable as a structural material, the next group includes concrete, stones with crystalline components, glass, various plastics, clay bricks, soft stones of sedimentary origin are more preferable. The best are materials of biogenic origin - wood, straw and other plant materials, unburned soil blocks, etc.

Now in urban construction, houses made of a set of reinforced concrete products with brick-monolithic enclosing structures, with a “wide step”, with free-planning and increased comfort apartments, improved heat and sound insulation, fire resistance and architectural and construction solutions that meet modern requirements are most widely used.

Concrete is one of the oldest building materials and is the most widely used building material today. Research and development of scientists give reason to believe that concrete and reinforced concrete will not give up their leading positions in the near future.

The building materials market is huge. New materials and technologies are constantly appearing, but often a person, before buying one or another, has no idea about the quality, composition and safety for his health.

Hazardous building materials include:
plywood, chipboard (chipboard), fibreboard (MDF) produced using phenol, formaldehyde and urea, decorative sheets and boards from polymer compositions;
vinyl and other types of self-adhesive wallpaper (synthetic-based films - isoplene, devilon, seinex, baseless polyvinyl chloride decorative films);
solid carpets made of synthetic fibers on an adhesive composition, linoleums based on polyvinyl chloride, synthetic tiles;
vinyl chloride, epoxy and other synthetic varnishes and paints;
plastic windows.

Wood and its derivatives are the most widely used biopositive building material, which makes it possible to obtain light, durable, non-combustible, non-rotting structures (with the help of special processing). A tree during its growth period is also a natural filter for pollution, releases substances useful to humans into the air, enriches the atmosphere with oxygen, and the soil with humus, creates niches for the existence of various animals. The forest used for the manufacture of building materials is fully restored, and the natural environment "does not notice" the removal of a small part of the forest. Modified wood is an excellent and fairly high-strength material that can be reinforced. Walls made of wood "breathe" and provide a favorable microclimate inside the premises. Therefore, wood can be considered one of the most promising biopositive building materials.

The next in terms of environmental friendliness are building materials and clay products: baked ceramic products (bricks, large-sized hollow stones for walls and floors, tiles, tiles, unbaked clay bricks mixed with straw and fishing line, etc.) - The least energy-intensive bricks made from dried clay in a mixture with straw reinforcing it, they have been used for many centuries in the construction of buildings of different heights in a dry climate or with reliable protection from moisture. A quarter of all the inhabitants of the Earth live in houses built from sun-dried mud bricks, and these buildings in countries with dry climates stand for hundreds of years.

The undoubted advantage of this building material is its complete recyclability, and the disassembled material can also be used as an additive to the soil for growing plants. It is interesting that two-three-story residential buildings made of dried clay have been successfully operated for many centuries in highly developed countries, for example, in France. The main problem of ensuring the durability of such buildings is protection from moisture with the help of a reliable roof and waterproofing from groundwater.

Among the non-renewable materials, aluminum and glass can be distinguished as almost completely (90%) recyclable materials, moreover, their re-manufacturing requires much less energy. Reducing energy consumption in the production of biopositive building materials is a very important task, as it allows not only to reduce their cost and reduce energy consumption, but also to pollute the environment less. So, in the primary production of 1 m3 of aluminum, a very large energy consumption is required - 7250 kW. h (for comparison, to obtain 1 m3 of cement, 1700 kWh is required, fibreboard - 800, brick - 500, aerated concrete - 450, wood - 180 kWh).

Such a high energy consumption, it would seem, makes aluminum a non-environmental material, however, when re-manufactured from scrap, energy costs will be about 600 kW. h, which allows us to consider aluminum an environmentally friendly material. It is necessary to gradually limit the use of building materials from non-renewable resources (cement, steel, concrete, reinforced concrete, plastics, etc.), which, moreover, require significant energy costs, are poorly recycled, do not allow creating a favorable indoor climate, and significantly pollute the environment when manufacturing. Each time you choose a building material, you need to compare options, taking into account the environmental friendliness of the materials and local experience.

The concept of environmental friendliness (biopositivity) of building materials also includes the impossibility of releasing harmful substances during the period of operation: for example, some natural stone materials (granite, syenite, porphyry) have an increased radioactive background; plastics or building materials with their use (fibreboard, linoleum, synthetic paints, synthetic tiles for flooring and cladding, various synthetic additives to concrete, mortar, synthetic adhesives, synthetic-based insulation, etc.) emit dangerous gases into indoor air for a long time ; asbestos-containing products, especially those subject to weathering with the release of asbestos fibers into the air, are recognized as unacceptable in a number of countries. All this can be very harmful to people in the premises, especially children.

It is impossible to choose completely sustainable materials for all building structures and finishes, except for small houses. Therefore, when choosing materials and comparing options, preference is given to more environmentally friendly materials (for example, clay bricks and ceramic products, gypsum-based materials, organic-based linoleum, paper-based or foam concrete insulation, wooden windows and doors, organic paints, etc.). ).

The impact of electric and magnetic fields on health:
Exposure (that is, being exposed to something) to the influence of the fields occurs everywhere: at home, at work, at school and in vehicles driven by electricity. Wherever there are electrical wires, motors and electronic equipment, electrical and magnetic fields.

Many people are similarly exposed to higher levels of fields, albeit for shorter periods of time, in their homes (through electric radiators, shavers, hair dryers and other household appliances, or stray currents due to imbalance in the building's electrical earthing system), at work (in certain industries and offices requiring proximity to electrical and electronic equipment) or even while traveling on trains and other electrically powered vehicles.

The fields cause physiological changes such as slow heart rate and electroencephalogram (EEG) readings, as well as a wide variety of symptoms and ailments, mainly related to the skin and nervous system. There may be scattered lesions of the facial skin, such as redness, pinkness, roughness, fever, warmth, tingling sensations, dull pain and "tightness". Symptoms related to the nervous system may occur, such as headache, dizziness, fatigue and lightheadedness, tingling and tingling sensations in the extremities, shortness of breath, rapid heart rate, profuse sweating, depression, and memory problems.

There are two possible mechanisms that may somehow be implicated in cancer activation and therefore deserve special attention. One of them is associated with a magnetic field-induced reduction in nocturnal melatonin levels, and the other is associated with the detection of magnetite crystals in human tissues.

From animal studies, it is known that melatonin, through its effect on the level of circulation of sex hormones, has an indirect oncostatic effect. Animal studies have also found that magnetic fields suppress the production of melatonin in the pineal gland. This finding suggests a theoretical mechanism for the marked increase in (for example) breast cancers that may be due to exposure to such fields. An alternative explanation for the increased risk of cancer has recently been proposed. Melatonin has been shown to be one of the most potent hydroxyl radical scavengers, and therefore the extent of the damage that free radicals can cause to RNA is markedly reduced by melatonin. If the level of melatonin is suppressed, for example, by a magnetic field, then RNA remains more vulnerable to oxidative attacks. This theory explains how the inhibition of melatonin by magnetic fields can lead to a higher incidence of cancer in any tissue.

But does the level of melatonin in human blood decrease when a person is exposed to weak magnetic fields? There are some indications that this may be the case, but this issue still requires further research. It has been known for some time that the ability of birds to navigate seasonal migrations It is mediated by the presence of magnetite crystals in the cells, which react to the Earth's magnetic field. Now, as discussed above, magnetite crystals have also been found in human cells at concentrations theoretically high enough to respond to weak magnetic fields. Thus, the role of magnetic iron crystals must be taken into account in all discussions about possible mechanisms that can be proposed to explain the potentially dangerous (harmful) effects of exposure to electric and magnetic fields on the human body.

General Tips:
In the first place, attention should be paid to how to avoid the influence of electromagnetic fields. The basic rule here is: protect, turn off and keep your distance!

An experienced professional, such as an electrician or a building biologist, can take measurements. Such specialists can give guidance on whether something needs to be changed or will do it themselves.

Keep your distance!
Electric and magnetic fields are very quickly released from the current source. The distance from the bed to electrical appliances and wires should be approximately 1-1.5 m. From the wall near which there is a cable (even hidden) or sockets, electric fields also emanate, even if no devices are working.
If possible, keep your head away from heat pipes and water pipes.
TV/computer
Televisions, receivers, video equipment and computers should not be in the bedroom.
Stay away from electrical appliances.
Remove the plug from the socket when the device is not in use.

Lamps
With a very high current alternating current, huge magnetic fields are created, which can have an effect on people located on another floor.
Transformers and dimmers must be disconnected from the network completely during the period when they are not in use. The so-called electronic transformers generate a frequency of 40 kHz and it is advisable not to use them at all.
home electrical appliances
Use as few electrical appliances and cables as possible.
Do not locate the bedroom near the wiring risers and protective shields.
There should not be wires near the wall near which the bed is located, and they should not be on the other side in the next room.
Discard the extension cord or, if necessary, use with as short a cord as possible.
Do not place electrical appliances near a wall if there is a bed on the other side of the same wall.

For all electrical appliances, there is a rule: after using them, the plug must be removed from the socket, because. This is the only way to stop the flow of current.

Use only regular telephones with cable attached. Cordless phones can cause strong high frequency fields.
Cell phones should not be in the bedroom.

Room planning.
Bedrooms and living rooms should be located as far as possible from the kitchen, laundry and boiler room.
Wiring risers and switchgears should not be located on the walls of living rooms or bedrooms.

When carrying out electrical installation, take care of grounding.
When running the cable, leave free space where you sleep or sit.
Do not place a boiler, washing machine, electric stove and other similar electrical appliances in close proximity to living quarters.

Besides:
Remove heating pads from bed before bed.
Avoid electric underfloor heating if possible.

Ministry of Education and Science of the Russian Federation

federal state budgetary educational institution higher professional education

"NATIONAL RESEARCH TOMSK POLYTECHNICAL UNIVERSITY"

Faculty - Institute of Natural Resources

Direction (specialty) - Chemical technology and biotechnology

Department - TOV and PM

Environmental problems of polymer production

by discipline " Innovative development chemical technology of organic substances"

Executor

E.V. Zenkova student gr.5a83

Supervisor

L.I. Bondaletova Senior Lecturer, Ph.D.

TOMSK 2012

Introduction

.Ecological problems in the chemistry and technology of polymeric materials

.Classification of polymer waste

3.Methods for recycling and neutralization of polymeric materials

.Waste water treatment and gas emissions

4.1Wastewater Treatment Methods

4.2Methods for cleaning gas emissions from polymer industries

5.Basic principles for the development of non-waste technologies

Conclusion

Introduction

Polymer production is one of the most dynamically developing industries. The world production of polymers in 2010 amounted to 250 million tons and is growing by an average of 5-6% annually. Their specific consumption in developed countries has reached 85-90 kg/person. per year and continues to grow. This interest of polymer manufacturers is primarily associated with the possibility of obtaining a variety of technically valuable materials based on them.

Due to the unique physicochemical, structural and technological properties, polymeric materials (PM) based on various plastics and elastomers are widely used in various fields of the national economy and medicine.

The vital activity of society is inevitably associated with the formation of waste at all stages of the production and processing of polymeric materials. Therefore, the urgency of the problem of their disposal, as well as the harm caused to human health and the environment, remains acute.

1. Environmental problems in the chemistry and technology of polymeric materials

Polymer materials, as a rule, are multicomponent systems, since, in addition to the polymer, various components (ingredients) are used to create them. Obtaining polymeric materials that meet the operational requirements for various industries, agriculture, and everyday life is the task of the technology for the production of polymeric materials. The multicomponent nature of polymers often leads to the fact that their production, as well as practical use in some cases, is complicated by the undesirable process of isolation of harmful low molecular weight substances from the material. Depending on the operating conditions, their amount can be up to several mass percent. Dozens of compounds of various chemical nature can be found in media in contact with polymeric materials.

The creation and use of polymers is directly or indirectly associated with the impact on the human body, on the surrounding production environment and human habitat, as well as on the environment as a whole. The latter is especially important after the use of polymers and products made from them, when waste materials are buried in the soil, and harmful substances released during the decomposition of the polymer material pollute the soil and wastewater, thereby worsening the state of the environment. Problems of ecology of production and application of polymeric materials.

What are the consequences of pollution, for example, of the earth? First of all, to the direct reduction of the natural habitat of living beings. Secondly, the pollution of some area creates a danger to neighboring territories due to the migration of pollution, for example, through subsoil aquifers. Thirdly, air pollution with harmful gases, including methane and carbon dioxide, which creates a greenhouse effect, can lead to global environmental changes.

The production of polyethylene, polypropylene, polyvinyl chloride brings considerable environmental problems to the environment. This is the use of various toxic monomers and catalysts, the formation of wastewater and gas emissions, the neutralization of which is associated with large energy, raw materials and labor costs and is not always carried out in good faith by manufacturers.

Consider some examples related to the ecology of the production of basic polymers.

The production of polyethylene and other polyolefins is classified as flammable and explosive (category A): ethylene and propylene form explosive mixtures with air. Both monomers have a narcotic effect. MPC in the air for ethylene is 0.05*10-3 kg/m3, for propylene - 0.05*10-3 kg/m3. The production of high-pressure polyethylene (LDPE) is especially dangerous, since it is associated with the use of high pressure and temperature. Due to the possibility of explosive decomposition of ethylene during polymerization, the reactors are equipped with special safety devices (membranes) and installed in boxes. Process control is fully automated. in the production of polyethylene low pressure and polypropylene, diethylaluminum chloride used as a catalyst is of particular danger. It is highly reactive. Explodes on contact with water and oxygen. All operations with organometallic compounds must be carried out in an atmosphere of pure inert gas (purified nitrogen, argon). Small amounts of triethylaluminum can be stored in sealed glass ampoules. Large quantities should be stored in hermetically sealed vessels, under dry nitrogen, or as a dilute solution in some hydrocarbon solvent (pentane, hexane, gasoline - so as not to contain moisture). Triethylaluminum is a toxic substance: when inhaled, its vapors act on the lungs, and on contact with the skin, painful burns occur. Gasoline is also used in these industries. Gasoline is a flammable liquid, the flash point for different grades of gasoline ranges from -50 to 28 °C. The concentration limits of ignition of a mixture of gasoline vapors with air are 2-12% (by volume). It has a narcotic effect on the human body. MPC of gasoline in air = 10.3*10-3 kg/m3. Powdered polyolefins form explosive mixtures. MPC for polypropylene is: 0.0126 kg/m3. When transporting powdered polyolefins, aerosols are formed and charges are inevitably accumulated. static electricity, which can lead to sparking. Transportation of polyolefins through the pipeline is carried out in an inert gas atmosphere. A related polymer is polyvinyl chloride. The production and use of vinyl chloride is also classified as explosive and flammable (category A). Vinyl chloride in the gaseous state has a narcotic effect, a long stay in a room, the atmosphere of which contains a large amount of vinyl chloride, causes dizziness and loss of consciousness. MPC in working premises is 3*10-5 kg/m3. At a concentration of 1*10-4 kg/m3 it causes irritation of the mucous membranes, and the smell begins to be felt even at 2*10-4 kg/m3. Inhalation of vapors during open evaporation of the monomer causes acute poisoning. Other monomers used in the production of polytetrafluoroethylene, polytrifluorochlorethylene, polyvinyl fluorides are also no less toxic.

In this regard, it is necessary to ensure the control of environmental safety of the process of creating polymers and polymeric materials, their operation and destruction of PM waste after their use by humans.

2. Classification of polymer waste

According to the sources of formation, all polymeric wastes are divided into three groups:

technological production waste;

industrial consumption waste;

public consumption waste.

Technological wastes of polymeric materials arise during their synthesis and processing. They are divided into non-removable and disposable technological waste. Edges, cuttings, sprues, fragments, burrs, etc. are irremovable. From 5 to 35% of such waste is formed. Non-disposable waste is a high-quality raw material that does not differ in properties from the original primary polymer. Its processing into products does not require special equipment and is carried out at the same enterprise. Disposable technological production wastes are formed in case of non-compliance with technological regimes in the processes of synthesis and processing, i.e. this is a technological defect that can be minimized or completely eliminated. Technological production waste is processed into various products, used as an additive to the feedstock, etc.

Industrial consumption waste accumulates as a result of the failure of products made of polymeric materials that are not used in various industries (tires, containers and packaging, agricultural film waste, fertilizer bags, etc.). These wastes are the most homogeneous, least polluted and therefore are of the greatest interest in terms of their recycling.

Public consumption waste accumulates in our homes, food establishments, etc., and then ends up in city dumps. Ultimately, they move into a new category of waste - mixed waste. These wastes make up more than 50% of the waste of public consumption. The amount of such waste is constantly growing and in Russia is about 80 kg per capita. The greatest difficulties are associated with the processing and use of mixed waste. The reason for this is the incompatibility of thermoplastics that are part of household waste, which requires a step-by-step selection of materials.

The volumes of industrial and domestic waste in the form of obsolete polymer products are significant and are gradually increasing, taking into account progressive packaging materials for technical and household items: food, soft drinks, medicines; decommissioning of polyethylene film, greenhouse farms, fodder production; bags of mineral fertilizers, household chemicals, nylon nets, household items, social and cultural life, children's toys, sports equipment, carpet floor coverings, linoleum, shipping containers, containers; waste production and operation of cables, polymer pipes, etc.; PET containers and packaging and other products based on PET.

In addition, mass imports of industrial, food products, medical supplies, cosmetics, etc. in polymer packaging increase the volume of these wastes.

These wastes are specific, since they are not susceptible to decay, self-destruction, accumulate, occupying land areas, polluting settlements, water bodies, and forest plantations. When burned, toxic gases are emitted; in landfills they are a favorable environment for the life of rodents and insects.

Thus, industrial and domestic wastes of polymer products represent an environmental hazard.

waste water recycling polymer

3. Methods for recycling and neutralization of polymeric materials

What approaches are used to combat environmental pollution associated with the production of polymers?

.Thermal methods of recycling and neutralization of waste polymeric materials. It would seem that the most natural could be the oxidation of these organic substances during high temperatures or simply burning them. However, in principle, valuable substances and materials are destroyed. combustion products in best case are water and carbon dioxide, which means that it is not possible to return even the original monomers, the polymerization of which produced destroyable polymers. In addition, as mentioned above, the release of large amounts of carbon dioxide CO2 into the atmosphere leads to global undesirable effects, in particular, to the greenhouse effect. But even worse, when burned, harmful volatile substances are formed that pollute the air and, accordingly, water and land. Not to mention numerous additives, including dyes and pigments, various compounds are released into the environment, including heavy metals used as catalysts in the synthesis of polyethylene, which are extremely harmful to human health.

Thermal methods for processing polymer waste can be conditionally divided into:

for thermal degradation of polymeric materials to obtain solid, liquid and gaseous products;

to incineration or inhalation leading to the formation of gaseous products and ash.

In turn, thermal destruction is conditionally divided:

on shallow thermal decomposition of polymers at relatively low temperatures with the formation of mainly low molecular weight substances;

to pyrolysis at elevated temperatures, resulting in liquid and gaseous products and a small amount of solid residue.

With the help of pyrolysis, you can get whole line useful products, however, this method is considered to be very energy-intensive and requires the use of expensive equipment. There is such a method as depositing polymer waste at landfills, which is clearly inappropriate, since most plastics do not decompose for decades, causing great damage to the soil. Thus, the traditional methods of waste disposal - deposition and incineration for polymers are unacceptable. In the first case, as a result of exposure to water, harmful amine-containing products are formed, in the second, toxic gases are released, such as hydrogen cyanide, nitrogen oxides, etc.

.Creation of polymeric materials with controlled service life. In recent years, new ideas for the synthesis of "environmentally friendly" polymers and products from them have arisen and have begun to be put into practice. We are talking about polymers and materials from them, capable of more or less quickly decomposing in natural conditions. It should be noted that all biological polymers, that is, polymers synthesized by plants and living organisms, which primarily include proteins and polysaccharides, are more or less susceptible to degradation, which is catalyzed by enzymes. Here the principle is observed: what nature creates, it is capable of destroying. If this principle did not work, then the same polymers, produced in huge quantities by microorganisms, plants and animals, would remain on the earth after their death. It's hard to even imagine, because it would be a fantastic world dump of corpses of all organisms that existed on earth. Fortunately, this does not happen, and highly efficient biological catalysts - enzymes - do their job and successfully cope with this task. Three types of degradable polymeric materials are known, namely:

photodegradable;

biodegradable;

water soluble.

All of them have sufficient stability under normal operating conditions and are easily decomposed. To give polymeric materials the ability to break down under the influence of light, special additives are used or they are introduced into the composition of a photosensitive group. In order for such polymeric materials to be found practical use, they must meet the following requirements:

as a result of the modification, the operational characteristics of the polymer should not significantly change;

additives introduced into the polymer should not be toxic;

polymers must be processed by conventional methods without being subjected to degradation;

it is necessary that products obtained from such polymers can be stored and operated for a long time in the absence of direct penetration of UV rays;

the time to failure of the polymer must be known and vary widely;

Known polymers decomposing under the influence of microorganisms. In this case, substances were introduced into the polymer, which themselves are easily destroyed and absorbed by microorganisms. Grafted copolymers of starch and methyl acrylate, films of which are used in agriculture for soil mulching, have found practical importance. Unbranched paraffinic hydrocarbons are very well absorbed by microorganisms. Biodegradable additives include carboxycellulose, lactose, casein, yeast, urea, and others.

.Compositions containing waste polymeric materials.

Waste polymer materials are widely used in construction. In most asphalt pavements, bitumen of various nature is the main binder component. They are not water resistant. All this significantly worsens the properties of asphalt pavements and reduces their service life. The use of polyolefins in the composition with bitumen is one of the traditional ways to modify the properties of coatings. It has been experimentally established that it is not advisable to introduce more than 30% of waste into polyolefins, since this can cause delamination of the system. Compositions are obtained by mixing bitumen with polyolefin waste at 40...100 °C, and the mixture is unloaded into special molds, in which cooling occurs at room temperature.

The following areas of use of waste in construction can be distinguished:

use in compositions with traditional building materials in order to modify their properties;

obtaining soundproof plates and panels;

creation of sealants used in the construction of buildings and hydraulic structures.

.Use of waste polymer materials through recycling. A much more promising and reasonable way to reduce environmental pollution with polymers is the recycling of used polymers and products made from them. This problem, however, is not as simple as it might seem at first glance, if only because we are dealing, as a rule, with dirty waste, which includes, for example, sand particles. This excludes the possibility of using high-performance and high-tech equipment used in the primary processing of initial polymers. This equipment would simply fail quickly due to the abrasive action of mineral solids. But even during processing, if it is possible in principle, "dirty" products are obtained, marketable condition And consumer properties which cannot compete with the original products. Here, however, there is an opportunity to use recycled products for other purposes, which require significantly lower requirements. In particular, contaminated polyethylene products can be processed into sheets several millimeters thick for use as a roofing material having a range of undeniable advantages before traditional ones, such as low density, which means low weight, flexibility and corrosion resistance, as well as low thermal conductivity, which means good thermal insulation properties.

General scheme recycling of polymeric materials includes the following stages:

pre-sorting and cleaning;

grinding;

washing and separation;

classification by type;

drying, granulating and processing into a product.

The greatest success in this has been achieved in the recycling of large-tonnage rubber products, such as tires, including automobile tires. They are prepared from vulcanized rubbers filled with soot, the content of which in tires, which are therefore black, reaches 40% by weight. At the end of their service life, such tires are not thrown away, but crushed, getting a crumb. Crushing using inexpensive equipment allows you to get large particles, the size of which reaches one millimeter or more. These large particles are added to pavement materials, which greatly improve their mechanical performance and durability. Special machines make it possible to obtain fine dispersions, the particles of which have a size of about 0.01 millimeters. This crumb is added to rubbers in the production of new tires, significantly saving raw materials. At the same time, the quality of the tires obtained in this way is practically not inferior to the original ones. This approach allows at the same time to significantly reduce the harm to the environment due to its littering with useless products and at the same time significantly save the consumption of rubbers obtained either by polymerization of oil refining products or from the latex sap of hevea trees.

4. Wastewater treatment and gas emissions

1 Wastewater treatment methods

Most of the enterprises producing synthetic polymers and plastics generate a large amount of wastewater containing pollutants of various origins. They are discharged without deep purification into rivers, water bodies and thereby pollute them, which leads to environmental degradation. At present, this problem has become so urgent that in the future it is necessary to completely exclude the formation of wastewater up to their complete elimination on the basis of cyclic processes. The most economical use of water will reduce the volume of wastewater; their complete elimination and minimal consumption of fresh water is possible only through the creation of closed-loop processes operating in a closed cycle. The experience of designing such facilities has shown that, in addition to all other advantages, it is also more economical than an open scheme with wastewater discharge and treatment.

The following are the most commonly used methods:

· to remove coarse particles - settling, flotation, filtration, clarification, centrifugation;

· to remove fine and colloidal particles - coagulation, flocculation, electrical precipitation methods;

· for purification from inorganic compounds - distillation, ion exchange, cooling methods, electrical methods;

· for purification from organic compounds - extraction, absorption, flotation, biological oxidation, ozonation, chlorination.

· for cleaning from gases and vapors - stripping, heating, reagent methods;

· for the destruction of harmful substances - thermal decomposition.

The treatment methods used are determined by the volume of wastewater, the amount, dispersion and composition of impurities. Due to the numerous impurities and their layered composition, as a rule, cleaning methods are used in a complex manner.

The creation of efficient treatment plants at enterprises is intended for:

· prevention of pollution of natural waters by industrial effluents;

· reduction in water consumption, as the return of purified water to the production cycle allows you to organize the water cycle at the enterprise.

2 Methods for cleaning gas emissions from polymer industries

The production of polymeric materials is accompanied by the release of toxic substances contained in gas emissions. Depending on the volume and composition of gas emissions, various methods their purification from toxic substances: fire, thermal catalytic, sorption-catalytic.

fire method. Direct combustion of gas emissions can be carried out both in drying plants and in boiler furnaces, in the latter the degree of neutralization is 99% at temperatures of 1000 ... 2000 ° C.

The thermal catalytic method of neutralization occurs at temperatures up to 400 °C. Purification of emissions consists in the oxidation of organic substances at 360...400 °C in the presence of platinum group catalysts. Oxidation of organic compounds goes to the formation of carbon dioxide and water. The degree of purification is 95…97%. The sorption-catalytic method is used to clean gas emissions with a low content of organic compounds.

5. Basic principles for the development of non-waste technologies

A waste-free process is a way of producing products in which raw materials and energy are used most rationally and comprehensively in the cycle: raw materials - production - consumption and secondary raw materials in such a way that any impact on the environment does not disrupt its normal functioning.

The most important principles underlying the BOP include the following:

consistency;

integrated use of raw materials and energy resources;

cyclicity of material flows;

environmental Safety;

rational organization;

combination and intersectoral cooperation.

The main thing in low-waste and even more so in waste-free production is not waste processing, but the organization of technological processes for processing raw materials in such a way that waste is not generated in the production itself. After all, production waste is part of, for one reason or another, unused raw materials: semi-finished products, defective products, etc., which are not utilized for a given period of time and enter the environment. However, in most cases, waste is a raw material for other industries and industries. Fundamentals of plastics processing technology.

The main requirements for the development of the BOP can be formulated as follows:

unconditional compliance with the standards of the content of substances in the air and water basins;

effective implementation technological process;

the use of the most economical (taking into account the observance of the first two requirements) technological schemes for cleaning gases and liquids.

The combination of the above three requirements poses the problem of choosing optimal solutions in a new way. Thus, from a purely technological point of view, the decommissioning of an enterprise operating using old technology, which is inevitably associated with significant emissions, may turn out to be premature. However, with an integrated approach to solving this problem, it may be justified to build a new workshop as soon as possible and liquidate the existing one. The lack of a rigorous economic assessment of the damage caused to the environment by harmful emissions still complicates the search for the optimal path. The most rational approach to solving the problem is, first of all, to improve the main technological process, which involves reducing the volume of circulating materials and eliminating possible gas and liquid emissions.

Conclusion

The current generation of people has finally become convinced that the environment around us - earth, water and air - does not have endless immunity against chemical exploitation. And although careless and careless handling of nature is still manifest today, people have already begun to understand and re-evaluate the catastrophic consequences of this.

The importance of solving environmental problems has led to stringent requirements for polymers and technologies for their production: the production of polymers must be environmentally friendly or at least have a minimal impact on the environment; polymers must be technologically recyclable after the end of their operation or biodegradable.

The widespread introduction of polymeric materials in various fields of human activity has posed a number of important problems for polymer specialists, including the problem of environmental protection. In order to competently solve these problems, it is necessary to know the methods of recycling and neutralization of polymeric materials. When introducing products from plastics into the national economy, for food and medical purposes, a mandatory qualified examination of the composition of released toxic substances and their quantitative assessment using highly sensitive and selective methods is necessary. Of particular importance in terms of reducing the amount of waste, their rational use, the creation of waste-free technologies, are the processes of processing secondary polymeric materials due to the shortage of primary polymers. Recycled polymeric materials occupy the same place in recycling processes as now occupies secondary raw materials in metallurgy.

List of sources used

1.Russian market for polymer waste processing. Analytical review. Moscow, 2010.

.Technology of plastics. Ed. V.V. Korshak. Moscow: Chemistry, 1985, 560s.

3.Problems of ecology of production and application of polymeric materials. Lirova B.I., Suvorova A.I., Uralsky State University, 2007, 24 p.

.A. B. Zezin, Polymers and the environment. Sorov Educational Journal, 1996, No. 2

5.Bystrov G.A. Equipment and waste disposal in the plastics industry. Moscow: Chemistry, 1982

.Sheftel V.O. polymeric materials. toxic properties. L., Chemistry 1982, 240s.

.#"justify">. Fundamentals of plastics processing technology. Ed. V.N.

Kulezneva, M.: Higher School, 1995, 527 pp., 2004, 600 pp.

.General chemical Technology polymers: textbook / V. M. Sutyagin, A. A. Lyapkov - Tomsk: Publishing House of Tomsk Polytechnic University, 2007. - 195 p.

10.Lyapkov A.A., Ionova E.I. Environmental protection technology. Tutorial. - Tomsk: Ed. TPU, 2008. - 317 p.

Similar works to - Environmental problems of polymer production

Usov Boris Aleksandrovich, Candidate of Technical Sciences, Associate Professor of the Department of Industrial

and Civil Engineering” Moscow State Engineering University (MAMI), boris_40@list.ru

Okolnikova Galina Erikovna, professor, Ph.D.,

Akimov Sergey Yurievich Lecturer, Department of Industrial and Civil Engineering, Moscow State University

Engineering University (MAMI)

ECOLOGY AND PRODUCTION OF BUILDING MATERIALS

Ecology as the science of the relationship between man and the natural environment arose at the end of the 19th century and since then has become increasingly important with every decade.

Keywords: ecology, building materials, industry

Ecology as the science of the relationship between humans and the natural environment had arisen at the end of the 19th century and since then, every decade has become increasingly important.

Keywords: ecology, construction materials, industry.

Environmental problems with industrial waste

The state of the environment and ecological problems are directly related to the volume of industrial production, which has increased more than 50 times over the 20th century, and 4/5 of this growth has occurred since 1950.

Almost any production is based on the extraction of natural raw materials from the bowels of the earth and its processing into the required product, accompanied by the formation of man-made waste and their pollution of natural resources.

environments. The amount of man-made waste generated is directly related to the volume of production of the main type of product and the perfection of the technology for its production.

Technogenic wastes pollute the atmospheric air, occupy and pollute the earth, groundwater. All wastes, depending on their toxicity, are divided into four classes: I - an extremely hazardous substance; II - highly hazardous substance; III - moderately dangerous substance; IV - low-hazard substance. Hazard class I waste is directed

are disposed of in "burial grounds" for indefinite disposal, less dangerous - in sludge - storage tanks, tailings, dumps, etc., under which more than 100 thousand hectares of land are occupied. Total amount waste accumulated on these dumps cannot be accounted for.

The emission of harmful substances into the atmosphere by enterprises of the building materials industry is carried out in the form of dust and suspended particles (more than 50% of the total emission), as well as carbon monoxide, sulfur dioxide, nitrogen oxides and other substances.

Of the emissions from building materials enterprises, more than 40% are accounted for by the cement industry, 18-20% - by the production of roofing and insulation materials, 10% - by asbestos-cement production, 15% - by non-metallic building materials, less than 10% - by the production of concrete and reinforced concrete structures and products.

The share of polluting emissions into the atmosphere from the building materials industry in Russia is 3.2% of the total amount of polluting emissions. The main volume of which falls on the fuel and energy complex (48.4% of atmospheric emissions, 26.7% of polluting wastewater discharges and over 30% of solid waste). For non-ferrous metallurgy - 21.6%, consisting of

solid waste (dump metallurgical slag, tailings of ore dressing, overburden); ferrous metallurgy (15.2% in the form of 90 million tons, including - 50 million tons of blast-furnace slags, 22 million tons of steel-smelting, 4 million tons of ferroalloys) some chemical production- in the form of sludge, spent hydrochloric and sulfuric acids, dither liquids and sludge from ammonia-chloride production, soda ash, phosphogypsum, fluorogypsum, etc. - that is, mainly waste of the fourth class, which allows their placement in the production of building materials.

And in general, from the above waste - leads to the need to create "secondary", but already man-made deposits.

Cement production is a major source of carbon monoxide formation: for 1 ton of cement - 1 ton of CO2, for 1 ton of clinker - from 1.5 to 9.5 kg of nitrogen oxides, solid particles with flue gases - from 0.3 to 1.0 kg / T. Although a significant part of the cement dust is captured by filters and sent back to the kiln.

Research has established that many man-made wastes are similar in their chemical and mineralogical composition to natural mineral raw materials and can be partially or completely used in the production of cements, without clinker.

binders, aggregates, which will save natural resources. However, in a number of industries, only an insignificant part of the consumed natural resources is converted into the required final product, and the main amount goes into industrial waste.

For their removal, an average of 8-10% of the cost of manufactured products is spent on the storage of solid waste. Only Moscow enterprises in the region are required to allocate up to 20 hectares of land annually. And besides, their transportation and warehousing consumes billions of rubles.

Therefore, the use of such wastes is becoming a top-priority global problem of resource conservation of natural raw materials.

At the same time, the problem of the presence of waste can also be considered as a huge additional wealth, if used correctly.

This priority is supported by the fact that - the most capacious consumer of industrial waste from various industries are large volumes of production of building materials, since many wastes are similar in composition and properties to natural raw materials for their production. The share of raw materials from them reaches more than 50%.

It has been established that industrial waste can cover up to 40% of the construction needs for raw materials. In addition, industrial waste in some cases can reduce the cost of manufacturing building materials by 10-30% compared to production from natural raw materials. It is possible to create new building materials with high technical and economic indicators from industrial waste.

However, the increase in the mass of processed materials is accompanied by a significant increase in the amount of waste that has a negative impact on the biosphere.

Therefore, the environmental criterion in the selection of the most advanced technologies becomes decisive.

At the same time, it is important to search not only for economically and environmentally efficient production, but most importantly, their optimal combination.

The solution of environmental environmental problems in the production of building materials is carried out in the following areas:

the first is to identify the volumes and study the nature of production wastes that pollute the environment, and their storage with the establishment of ways to eliminate them by actions aimed at their further processing.

the second is the capture and disposal of environmentally harmful solid waste with the introduction of technological solutions for the complex processing of such raw materials or the use as secondary products of other industries.

the third is the creation of environmentally "clean" non-waste technologies with the complete exclusion of environmental pollution.

Measures in the first direction are basically determined. Waste is either prepared for recycling or landfilled.

Works on environmental protection in the second direction are widely deployed: the energy intensity of production is reduced by equipping the main technological units with heat recovery units and extensive preparation of various wastes (sludge, slag, ash, etc.) for reuse. That is, in relation to industrial waste, a new stage of environmental protection is already being embodied in material production - the idea of ​​complex processing of raw materials. For example, when creating large metallurgical or energy complexes, it is also planned to prepare waste for use in the production of building materials. So there were also widely

However, granulated metallurgical slags are used for the production of Portland slag cement, slag pumice, slag wool, etc. There is experience in the use of dump slags, flotation tailings, etc. for these purposes.

The positive experience of using slags as a concrete filler, and concrete waste as a low-grade binder or in the form of crushed aggregate for producing concrete grades up to 200 kg/cm2 was determined. But the complex use of raw materials in the production of building materials and especially in the manufacture of the most common and versatile material - ordinary concrete is still not enough.

Thus, construction technologists from mass inorganic industrial waste are primarily attracted by metallurgical slag, fuel waste (ash, slag), as well as waste coal-bearing rocks - waste from coal mining. Today, various wastes of pulverized microsilica in the form of ferrosilicon and other compounds, even non-ferrous metallurgy, are successfully used. In the production of 1 ton of pig iron, about 0.7 tons of blast-furnace (slag) melts are formed.

However, unfortunately, in the production of building materials

only about half of the slag waste is used; the rest is sent to the dump. Part of the waste slag is used as crushed stone in the construction of roads. However, due to the slow cooling of direct waste - slag melts in dumps, which also contain impurities of molten iron and therefore acquire high strength, the production of crushed stone is associated with very high costs (explosive work and very expensive crushing).

On the other hand, it is possible to cast various products from slag melts: crystallized paving stones, slabs for paving streets and sidewalks, curbstones, etc. They also produce porous aggregates (slag pumice), and by controlled crystallization, valuable materials - slag-ceramics. For example, sitalls are glass-crystalline materials or synthetic stones that differ from natural ones in a fine-grained uniform microstructure, which contributes to the creation of materials of high durability and strength. That is, by adjusting the compositions of only melts, it is possible to obtain synthetic materials with a given set of physical and chemical properties. Since the technology of slag-smelting is similar to the technology for the production of glass products, then for them

production equipment suitable for the glass industry. In addition, slabs for wall and floor finishing, panels for combined roofs, hinged and self-supporting panels of external walls, sanitary equipment, pipes for gasification, heating, for chemical industry and agriculture; pillars, fences, durable sculptures.

Expanded slag-sitall - foam-slag-sitall is a good and cheap heat-insulating material. Combining slag pumice (thermosite) with melts, large blocks and products (slag stone) are cast.

The use of slag melts for the manufacture of various profiled products instead of products from specially melted basalts is very promising.

From an incomplete list of slag materials, it follows that metallurgical slags are indeed a particularly valuable type of raw material.

Other waste: ashes and fuel (boiler) slags are formed from the burning of hundreds of millions of tons of coal, oil shale and peat, saturating the atmosphere with acidic products. Only from burning 1 ton of coal, from 100 to 250 kg of fuel waste is obtained. Although many industries are switching to natural gases, as well as to

gas obtained by gasification of various coals. But even after gasification from 1 ton of coal, from 0.2 to 0.4 m3 of slag and ash remains.

All this requires huge areas for burial.

At the same time, fuel waste (slag and ash) is a good raw material for the manufacture of many building materials. For example, some ash from the combustion of oil shale are binders, other ash and slag are used to produce lightweight concrete (slag concrete, ash concrete, especially light "cellular" concrete - aerated concrete and foam concrete).

Waste of "blank" rocks extracted from coal mines and consisting of coal-clay shale with a content of 10-15% of coal and sulfur impurities form from spontaneous combustion (with an increase in temperature up to 800-1000 ° C) - "burnt rocks" - waste heaps. Spoil heaps smoke for a long time, transforming from waste rocks into a kind of slag, which are used like fuel waste. But most often they are burnt and swollen clays, from which it is possible to obtain agloporite by crushing.

Another type is organic waste and, in particular, wood waste. In our country annually cuts down-

about 1/3 of the annual growth of wood is about several hundred million cubic meters. At the same time, about 4 m3 of logs are taken out of the forest for every 5 m3 of cut wood, and after sawing them, less than 3 m3 of lumber is obtained, the rest is waste (longevity, short, slabs, slats, shavings, sawdust). The output of lumber, taking into account shrinkage, averages 55-60% of the volume of the log. The total amount of wood waste annually is more than 150 million m3. Of these, in the form of slabs and slats - up to 25%, and sawdust - 10%. Another part is used as fuel, the rest is not used.

If these wastes are converted into shavings or cellulose fibers and mixed with synthetic resins, particle boards or fibreboards and a valuable addition to concrete in the form of fibers can be obtained.

Agricultural waste - fire (tow) of bast plants (flax, hemp, etc.), straw, etc. can be used to obtain heat-insulating and sound-proof boards, sheets and plates for finishing works(floors, walls).

1. The use of waste in the production of reinforced concrete

Today, a huge industry of building materials is reinforced concrete, for which there are already not enough natural components - quartz sand and crushed granite.

The coming 21st century should be the century of concrete based on man-made waste, which will allow not only the disposal of man-made waste, solve environmental, energy and environmental problems, but also raise concrete technology to a new ecological and economic stage of development.

The contribution of concrete science to solving environmental problems is considered in the following areas:

Reducing emissions of substances associated with the production of Portland cement and energy costs;

Reducing the consumption of clinker cement per 1 m3 of concrete without compromising its quality;

Replacement of the clinker part of cement, as well as natural aggregates, with industrial waste from other industries, including those containing toxic elements, due to their conversion into insoluble substances and conservation.

Today, waste is the basis of a new industry direction - chemicalization of concrete with the achievement of

him new technical indicators. So, ash, slag and ash and slag mixtures, used in concrete only to replace part of the cement, improve the workability of mixtures, provide the required strength and frost resistance of concrete up to F = 100-300, reduce shrinkage and water permeability. Ash increases the corrosion resistance of reinforced concrete and sulfate resistance of ordinary concrete, without affecting its creep deformation, shrinkage and modulus of elasticity.

The prepared ash and slag mixture (2) and slag are used instead of heavy aggregates of natural origin (sand, gravel and crushed stone), light (porous) aggregates of artificial manufacture (expanded clay, agloporite, etc.), natural origin (pumice, tuff, etc.) or in combined with them.

Dense slag - separate removal with subsequent cooling of the melt with water is applicable for enrichment of fine natural sands or as crushed stone of fine fraction - for heavy concrete.

Porous slag - solid removal can serve as a large aggregate in lightweight concrete.

At present, the classification and indicators of waste properties are included in regulations. So, in accordance with GOST 25818, according to the type of fuel burned, fly ash (dry ash selection) is subdivided

yut on anthracite (A), coal (CU) and brown coal, formed as a result of combustion brown coal(B).

Fly ash (FL) from thermal power plants is also used as a component for the manufacture of heavy, light, cellular concretes and mortars, as well as a finely ground additive for heat-resistant concretes. And depending on the field of application, they are divided into 4 types: I - for reinforced concrete structures made of heavy and light concrete; II - for concrete structures and products made of heavy and light concrete, mortar; III - for products and structures made of cellular concrete; IV - for concrete and reinforced concrete products and structures operating in particularly difficult conditions (hydraulic structures, roads, airfields, etc.).

According to the chemical composition of fly ash, they are divided into 2 types: acidic (K), containing calcium oxide (CaO) up to 10% by mass and basic (O), containing CaO more than 10% by mass, including in the memory of fuel B free CaOsv - not more than 5% for types I and II of ash and not more than 3% - for type IV. For type III CaOsv is not standardized.

The designations of ash grades take into account the above abbreviations.

Example: ZU KUK-1 GOST 25818 - coal (KU), sour (K),

fly ash (FL) for the manufacture of reinforced concrete structures must meet the following requirements:

I I I - 6% and IV - 3%;

II and IV types - no more than 1.5% and III - 3.5%; - PPP for sour storage from KU: I type - no more than 10%, II - 15%, III - 7% and IV - 5%; from A: type I - no more than 20%, II - 25%, III and IV - 10%; from B: type I - no more than 3%, II - 5%, III - 5% and IV - 2%; for the memory of the main ones from B: I,

III and IV types - no more than 3% and II - 5%. Specific surface of ash, m2/kg,

should be no more than 250 for acidic type I and III, for acid type II - 150 and for acidic

IV type - 300; for the main memory of type I - 250, the memory of the main type II - 200, the memory of the main III type - 150 and the memory of the main type IV - 300. The residue on the sieve No. more than 20%, ZU K II type - no more than 30% and ZU K IV type - not more than 15%; for memory about I and II types - no more than 20%,

I I I type - no more than 30% and IV type - no more than 15%.

Unfortunately, in Russia, out of (50 million tons) of the total volume of ash and slag waste generated, only no more than 11% falls on the share of fly ash.

However, in world practice, ash from thermal power plants from thermal power plants is an effective component of concrete in increased quantities (50-200 kg / m3) (and for high-strength concrete - microsilica or its combination with ash) is introduced into the vast majority of concrete and is considered as an obligatory component.

Ash introduced in large quantities requires a reduction by the same amount of certain components of concrete. The introduction of ash into the concrete mixture is possible instead of cement or instead of sand. These methods are interrelated (table 1).

Table 1

No. of composition Consumption of materials, kg/m3 yszh, MPa

water cement sand rubble ash

1 190 330 650 1200 - 25

2 200 230 590 1200 100 18,7

3 190 230 730 1200 - 13,6

4 200 229 531 1200 100 25

Concrete with an ash consumption of 100 kg/m3 of concrete (composition 2) can be obtained by introducing it by volume both instead of cement into composition 1 with a cement consumption of 330 kg/m3, and instead of sand into composition 3 with a cement consumption of 230 kg/m3.

Changes in volumes due to an increase in the water demand of the mixture with ash and a lower density of ash (р3 = 2.1 g/cm3) are compensated by an increase in sand consumption. In this case, the introduction of ash instead of cement can lead to a decrease in strength. The introduction of ash instead of sand is more effective: if the ash is effective, the strength increases (in the composition of 4 - by 14%). In practice, as a rule, it is usually required to keep the strength at a constant level. Why parts of the ash replace cement and sand.

The replacement proportions depend on the efficiency of the ash, the quality of which is quantified by the efficiency factor (Ke). Its physical meaning is the ratio of the masses of the reduced cement and the introduced ash, while maintaining a constant strength of concrete. When using Ke, the purpose of the composition of concrete with ash becomes clear. So, Ke = 0.5 means that when introducing into concrete, for example, 100 kg of ash to maintain strength, it is possible to reduce the consumption of cement by 50 kg and another 50 kg - the consumption of sand (when replacing by weight). If ash is introduced into composition 1 (Table 2) in order to obtain equal-strength concrete, then, assuming Ke = 0.31, we obtain composition 4 (replacement by volume).

Table 2. Effectiveness ratio of some evils

Consumption of cement, kg/m3 Type of ash/curing conditions

Angarskaya TPP(2) Bushtyrskaya TPP(3) Uglegorskaya TPP(4)

steaming normal reduction steaming steaming

240 0,39 0,46 0,5 0,39

300 0,31 0,36 0,4 0,42

350 0,2 0,79 0,33 0,45

400 0.2 0,25 0,5

Sometimes the “strength” interpretation of Ke is more useful: the ratio of the increase in strength with the introduction of any amount of ash and the same amount of cement. In this case Ke is defined more simply. Since the strength effect of increasing the consumption of cement in each production is known, it remains to establish the strength effect of the introduction of ash (instead of sand). As an example, you can use the data in Table. 1. The strength effect from 100 kg of cement is 11.4 MPa, and from 100 kg of ash -

5.1 MPa, whence: Ke = - = 0.45.

When using Ke, there are also difficulties associated with the dependence of its value on the consumption of cement, the amount of ash, the hardening mode (the above values ​​of Ke are valid for a certain consumption of cement).

Most Russian evils have an increased water demand,

Therefore, Ke decreases with an increase in cement consumption, and for low water demand ashes that plasticize the concrete mixture, it can also increase. In general, the data on the dependence of Ke on the consumption of cement are somewhat contradictory, so it is better to determine it experimentally.

With an increase in ash consumption, its efficiency decreases and the establishment of the dependence under consideration becomes laborious. Then it is possible to limit oneself to one ash consumption (for example, 100-150 kg/m3), and to consider a larger Ke at lower ash consumption as a certain safety factor. Such compositions can be further adjusted according to the results. production control strength of concrete.

The main type of ash introduced into concrete is low-calcium dry-disposal TPP ash. It is predominantly silicate glass, and the amorphous silica composing it is chemically active with respect to Ca (OH) 2 released during cement hydration (the so-called pozzolanic activity). The reaction between them leads to the formation of highly dispersed hydrosilicates

calcium (CaO8Yu^H2O type) with high astringency instead of low-strength Ca(OH)2, and grinding of particles leads to a decrease in pore size and permeability. All this improves the structure of concrete. Unfortunately, the pozzolanic reaction (with amorphous silica) starts late (at about 7 days of age) and proceeds slowly; its main effect during normal hardening of concrete is manifested by the age of 3 months, and intensive hardening of concrete with ash is observed at a later age - up to a year or more. As a result, the strength effect from the introduction of ash and cement savings, determined by 28-day strength, are lower than for older concrete. Nevertheless, this “ageing” effect is not lost, but will cause both an additional margin of safety and reduced permeability, and, consequently, increased durability of such concrete (of course, under conditions conducive to continued hydration at a later age).

In addition to the pozzolanic effect, ash also has a significant physical effect on concrete, which is commonly called the “microfiller effect”. In its pure form, it manifests itself in an increase in strength when inert powders are introduced into concrete, for example, ground sand, dusty crushing waste and

etc. Its basis can be considered an increase in the concentration of dispersed particles in the cement paste-stone, which causes a decrease in its porosity. Another aspect of this effect is manifested in concrete mixtures with low cement consumption, where there is a clear deficit of dispersed particles. The introduction of ash weakens or eliminates it, as a result, the grain composition of the cement-sand component improves, the delamination of the concrete mix decreases and the homogeneity of concrete increases. It should be noted that the "stabilizing" role of ash increases due to the trend of using highly mobile mixtures in monolithic construction, with an increased tendency to delamination.

With an increase in the consumption of cement, the delamination of the concrete mixture decreases, but the heat release of the hardening concrete increases, which can lead to the formation of microcracks already in the early stages of hardening. Reducing the consumption of cement with the introduction of ash reduces heat generation and the likelihood of thermal microcracks, which also improves the structure of concrete. In massive concrete, the risk of microcracks increases significantly, and the positive role of ash manifests itself in the entire range of cement consumption.

Ashes from thermal power plants that meet certain requirements can be introduced into concrete.

requirements, primarily to their chemical composition. GOST 2581891 normalizes: the content of CaO, MgO, BO3, alkalis, as well as losses on ignition. Of the indicators that determine the effectiveness of ash, in concrete for reinforced concrete products, only the specific surface is normalized.

Abroad, dispersion is used as the main characteristic of ashes for concrete. It is generally accepted that it is dispersity that determines such important properties of ashes as water demand, pozzolanic activity, micro-filling effect, loss on ignition. It is estimated by the residue on a sieve of 45 microns, considering that the specific surface of the ashes containing porous particles is not determined accurately. But foreign standards, for example, the European norms EN-450 "Ash for concrete", along with chemical composition, normalize not only dispersion, but also the activity index, which characterizes the strength effect of ash in a mixture with cement. In a number of standards, the water demand of ash is also normalized. By general principle- ash should not increase the water demand of the concrete mixture.

At the same time, ashes with increased water demand can remain quite effective in concrete. So the introduction of 100 kg of ash per 1 m3 of concrete instead of sand increased the strength

by 14%, despite the increase in the water demand of the mixture by 10 l/m3.

Of course, ashes with reduced water demand are more effective, especially in concretes with increased cement consumption.

The introduction of ash improves a whole range of properties of the concrete mix and concrete. It should be noted that this occurs simultaneously with a decrease in the consumption of cement in concrete with ash in accordance with Ke. A concrete mixture with ash, with the same mobility, is more plastic, easier to pump and fills the formed space, which is especially important under "difficult" laying conditions. Hardened concrete with ash, having a reduced permeability, increases durability, protective action in relation to reinforcement, hindering the diffusion of chlorine ions into concrete, as well as corrosion resistance. Sulfate resistance increases especially sharply. But these effects are achieved with prolonged moisture treatment, which provides a pozzolanic reaction in the surface layer of concrete, which is responsible for the listed properties.

At the same time, some negative consequences of introducing ash into concrete should also be taken into account. First of all, concrete hardening slows down in the early stages, especially at low temperatures. In some cases, especially with significant

ash consumption, it is possible to reduce the frost resistance of concrete, which is a complex function of ash consumption, the duration of concrete curing and the age at which frost exposure begins. Finally, it should be taken into account that the interaction of ash with Ca (OH) 2 during the pozzolanic reaction leads to a decrease in the alkaline reserve in concrete; at high ash consumption, there may be a danger of its complete binding and corrosion of the reinforcement. Therefore, the amount of ash introduced is limited.

GOST 25818-91 provides for the maximum allowable ratio of ash: cement as 1:1 by weight.

TPP slags, whose reserves amount to millions of tons, are an excellent raw material for the production of concrete. They are formed from the mineral part of coals burned in the pulverized state in the furnaces of boiler units.

Many areas of the country are experiencing an acute shortage of natural sands that meet the requirements of current standards, so builders are forced to use very fine sands with Mcr = 1,...1,2. This inevitably leads to excessive consumption of cement and a decrease in the quality of reinforced concrete structures. Recently, fine natural sands have been enriched with by-products and production waste. Rational use waste expands

raw material base of construction and reduces its cost.

According to the grain composition, slags are a mechanical mixture of slag sand (grain size 0.14-5 mm) and crushed slag (grain size more than 5 mm). The density of slag grains formed in the furnaces of boilers, units with liquid slag removal, is mainly in the range of 2.3-2.5 t/m3; the crushability of fraction grains 5-10 mm according to the GOST 8269 method is 20-25%, and the strength of cube samples with an edge of 2 cm, sawn from a piece of slag, reaches 150-200 MPa. That is, TPP slags are applicable as fillers for high-grade concrete, up to M700.

Given the high value of the particle size modulus (Mcr) of slag sand (3.05-3.96), it is advisable to use separate removal fuel slag as a component that improves the granulometry of fine sands.

Slag sand does not have the disadvantages inherent in many types of industrial waste - it practically does not contain flaky and needle grains, silty, clay and other harmful impurities. A certain amount of dust-like fractions, which can be contained in slags, without deteriorating the properties of concrete, significantly improves the rheological characteristics of the concrete mix.

Practice has shown that stable uniformity and strength of concrete can only be obtained with optimal dosing, taking into account the granulometry of the original sand and added slag. The method for calculating the composition of concrete, which ensures obtaining the optimal granulometry of aggregates and increasing the density and strength of concrete, takes into account that the fuel slag contains not only sand fractions, but also larger grains that replace crushed stone. In addition, the grain density of slag is lower than that of traditional hard rock aggregates, so the amount of slag aggregate should be less than the amount masses of quartz sand and crushed granite.

Structures of cement stone with silica waste with micro- and nano-sized particles

Today, the wide attention of technologists is attracted by environmentally very undesirable waste from ferrous, non-ferrous metallurgy in the form of silicate "smoke", which has even nanosized particles in its fractional composition. Their burial requires, in addition to the technological operations of preparation and storage, also covering the surface with humus with a lawn in order to prevent further dusting of waste in dry or hot weather.

With micro- and nanosized cement stone fillers, the phenomena and mechanisms involved in structure formation from their introduction as a modifier are relevant. The role of micro- and nano-sized particles in the processes of modifying the structure of cement stone and concrete is considered in the context of the influence of inclusions of their other size scales.

In technological materials science, each dimensional scale of "inclusion" of particles is correlated with its corresponding scale level of the structure, represented as a two-component subsystem "matrix - inclusion". This consistently applies to coarse, fine aggregates, microfillers, ultramicro- and nanosized particles. Each type of inclusion, “working” within its scale structure level, affects the structure of the entire material (as a composite). The last, and this is important, is the synergy of the effects obtained.

The need for systematic quantitative balance of the content of inclusions of different size scales is obvious. This problem is also related to the optimization of the dosage of micro- and nano-modifying particles.

The dimensional scale should be considered as the initial

th identification parameter of inclusions. Many identification characteristics of inclusions are associated with the dimensional-geometric and visually expressible feature - the specific surface area, specific surface energy, the number of particles and the number of particle contacts per unit volume (see Table 3), quantum-size effects and particle states, predetermining the manifestation of mechanical, physical and chemical effects on the processes of structure formation and the effects of transformation of the structure of materials.

Considering the possible mechanisms of participation of micro- and nano-sized particles in the processes of structure formation of cement stone and concrete, it is necessary to consider the system in which they initially find themselves.

These are polydisperse multiphase cement paste systems with the addition of initial dispersed particles into packages of a certain density. They develop the processes of wetting, adsorption, chemisorption, peptization, dissolution, hydration, colloidation, nucleation and phase formation with crystallization and recrystallization.

The “life cycle” of micro- and nano-sized particles is determined by the nature and degree of their involvement in these phenomena and processes of structure formation. It depends on the dimensional geometric and substantive characteristics, the dosage of micro- and nano-sized particles. IN general case structure-forming participation and transforming their influence become the result of the following interrelated mechanisms.

Table 3

Estimated characteristics of ions introduced into the structure of concrete

Name of inclusions Size, Specific surface area, m2/kg Specific surface energy, J/kg Number of particles per unit volume (in 1m3) Number of particle contacts per unit volume (in 1m3)

Coarse aggregate 510_3-4^10-2 Up to 0.5 Up to 0.6 Up to 1104 Up to 9104

Fine aggregate 510_4-5^10"3 Up to 24 Up to 30 Up to 5-106 Up to 4107

Microfiller 510_6-2^10-4 Up to 300 Up to 400 Up to 11012 Up to 91012

Microsilica 110"7-210-7 Up to 20,000 Up to 18,000 Up to 6-1018 Up to 4-1019

Nanosized particles 210_9-4^10-8 Up to 200,000 Up to 250,000 Up to 2-1022 Up to 11023

The first and well-known is the mechanism that determines the increase in the packing density of the system of addition of dispersed particles, the decrease in its total porosity, and the change in the porosity structure.

At the stage of development of wetting, adsorption, and chemisorption processes, the micro- and nanosized particles present in the system are able, by increasing the volume of adsorption and chemisorption bound water, to reduce the volume of capillary-bound and free water, resulting in a change in the technological rheological properties of the cement paste and concrete mixture, to increase their viscosity and plastic strength.

At the stage of colloidation, nucleation, and phase formation, micro- and nanosized particles are capable of acting as crystallization centers and lowering the energy threshold of this process and accelerating it.

Simultaneously manifesting effect of the influence of particles as crystallization centers will be the "zoning" of the hardening structure. Microvolumes of the hardening structure will be in the field of energy, thermodynamic influence of individual micro- and nanoparticles, which will be accompanied by the formation of agglomerates and crystallites from new hydrated phases. Size,

volume, the number of agglomerates and crystallites per unit volume will be determined by the quantum-dimensional state of the particles, their quantitative content (dosage) per unit volume of cement stone and concrete.

Zoning - as a process and as a result of the process of transforming the structure of cement stone, provides positive phenomena for the properties of concrete, since it is directly related to the characteristics of uniformity - the heterogeneity of the structure, the area of ​​​​the phase boundaries and, accordingly, to a change in the working conditions of the material under load in terms of concentration and localization , the formation of stresses and strains in it, the conditions for the initiation and propagation of cracks.

Another fundamentally important mechanism for modifying the structure of cement stone with the introduction of micro- and nanosized particles is associated with the possibility of their direct chemical participation in heterogeneous processes of phase formation of hydrated compounds. This possibility is determined both by the substantial sign (chemical and mineralogical composition) of the particles, and by the increased values ​​of their specific surface area and specific surface energy.

Thus, characterizing the mechanisms of the transformative influence of micro- and nanosized particles on

structure formation and structure of cement stone and concrete, one should generally keep in mind the spatial and geometric aspect (parameters of the system for adding dispersed particles, their packing density, porosity and porosity structure, zoning of the formation of a new phase), thermodynamic and kinetic aspect (energy facilitation of hydration processes and hardening, their acceleration), the crystal-chemical aspect (manifestation of the role of the crystal seed by the particles, the zoning factor of the amorphous-crystalline structure, the participation of the particle substance in the chemical-mineralogical processes of phase formation), and finally, the technological aspect (the effect on water demand, change rheological characteristics of molding sands).

However, the possibilities and measure of implementation of these mechanisms of structural transformation of cement stone should be determined by the type, characteristics and dosage of micro- and nanosized particles.

In this series, one of the most acceptable options is the use of nanosized silica particles due to their availability, the possibility of a relatively simple and inexpensive synthesis.

With the generality of the considered mechanisms of transformation of the structure of cement stone by microsized

and nanosized silica particles, there is a fundamental difference in the effectiveness of their application. This is primarily due to a significant difference in the size of micro- and nanosized silica particles, while micro- and nanosized silica particles are similar in their substantial nature.

The microsilica used today in practice (MS) (Fig. 1) is a by-product of the production of silicon and ferroalloys, consisting of 80-98% of amorphous silicon dioxide; the particles are spherical with an average diameter of 200nm; the specific surface area measured by the nitrogen adsorption method is 15,000 - 25,000 m2/kg; specific surface energy can reach 18 kJ/kg, and the number of particles per unit volume - 1018 pieces/m3.

Rice. 1. The main characteristics of silica dust: a - the shape and size of the grains (from a microphoto); b - particle size distribution curve

Sizes of silica nanoparticles are two orders of magnitude smaller

particle sizes of micro-silica and range from 1 to 20 nm; the specific surface area of ​​nanosized SiO2 particles can reach 200,000 m2/kg, and the specific surface energy - up to 250 kJ/kg. This creates a situation where most of the atomic bonds of nanoparticles come to the surface, thereby providing an extremely high specific surface energy related to the particle mass. The volume of capture of microsilica in Russia is 30-40 thousand tons. This is the most valuable superpozzolanic waste used for the production of superhigh-strength concretes.

An X-ray study of the kinetics of the process of structure formation of cement stone modified with SiO2 nanoparticles revealed the following regularities: the process proceeds much faster, since a significant amount of hydrosilicate phases is already present at a hardening time of 1 hour; the process of phase formation is characterized by the fact that the dominant phase in this case is more low-basic calcium hydrosilicates. With an increase in the duration of hardening, the content of this phase increases, while the number of 3CaO SiO2 phases decreases, and the content of the 2CaO2SiO2H20 and

(CaO) x ^ 102-pH2O. And this is due precisely to the introduction of SiO2 nanosized particles into the cement-water system. A significant difference between the use of nanosized particles is that their presence in the system is observed only in the initial period of hardening (8-24 hours); then they are not fixed. This is due to their extremely high chemical activity and ability to participate in reactions, probably also by the topochemical mechanism.

The high specific surface energy of microsilica particles and, especially, Si02 nanoparticles, changes the thermodynamic conditions chemical reactions and leads to the appearance of hardening products of a modified mineralogical, morphological and dispersed composition compared to the hardening system without additives.

2. Environmental assessment of waste from industrial enterprises (on the example of sulfur-containing waste)

There are solid theoretical scientific studies on the disposal of specific wastes (3), for example, sludge, ashes and slags from thermal power plants directly for the production of certain materials. Thus, technologies for obtaining waste from metallurgical, oil refining and petrochemical, chemical, energy enterprises have been developed and tested.

yatiya expensive aluminous and expanding cements, heat-resistant concrete, highly effective additives - for expanded clay, ceramic bricks and other materials.

However, despite the variety of building materials from industrial waste, waste recycling to the total mass of their generation is still low. And therefore, construction industry enterprises, comprehensively and stably using technogenic raw materials with valuable components, have not gained a mass character.

This is explained by a rather complex step-by-step integrated approach to the problem of waste disposal, but, of course, mandatory from the standpoint of protecting human health and the environment. In addition, it is supplemented by an economically feasible assessment of the use of technogenic raw materials, which ultimately determines - by all means increasing the coefficient of its useful use in comparison with existing industries - direct consumers of natural raw materials.

Technologically, the staged validity of the transformation of waste into technological raw materials for the production of building materials and their service in the operational conditions of building structures is determined by:

Establishing the suitability of technogenic raw materials for the needs of the construction industry;

The choice of technology for processing raw materials for the production of building materials.

At the same time, the determination of the suitability of classifying man-made waste as a “consumer” raw material also includes several stages of evaluation according to various criteria.

Stage I - Assessment of toxicity.

Waste toxicity is assessed by comparing the composition with MPC (maximum permissible concentration) of carcinogenic (toxic) substances and elements. There are three options here:

The waste contains a significant amount of toxic substances exceeding the MPC;

The waste contains small amounts of heavy metals;

There are no harmful substances in the waste.

In the first case, waste without special cleaning measures cannot be used in the production of building materials and is sent to landfill.

If there are impurities of heavy metals in the composition of the waste, it can be recommended for use in roasting technologies, provided that a melt sufficient for conservation (encapsulation) of heavy metals is formed in the mass.

In the absence of toxic elements, the considered waste is recommended for the second stage of the assessment.

Stage II - Radiation safety.

At present, the established practice of building construction, taking into account radiation safety, provides for monitoring the effective specific activity (Aef) of natural radionuclides (NRN)<К, <Ка, <ТП. Техногенное сырье, имеющее удельную активность ЕРН Аэф<370 Бк/кг (в соответствии с НРБ-96 ГН 2.6.1.054-96) относится к I классу материалов. Это сырье возможно применять для материалов, использующихся во вновь строящихся жилых и общественных зданиях.

If the specific activity NRN Aeff<740 Бк/кг, то такой отход можно отнести ко II классу материалов, и он должен использоваться только в дорожном строительстве в пределах территории населенных пунктов и зон перспективной застройки, а также при возведении производственных сооружений.

If the specific activity of the NRN of technogenic raw materials is Aeff<2,8 кБк/кг - III класс материалов. То отход следует применять для производства материалов, используемых только в дорожном строительстве вне населенных пунктов.

When Aeff>2.8 kBq/kg, the issue of the use of materials is resolved in each case separately in agreement with the federal agency of the State Sanitary and Epidemiological Supervision.

Stage III - Assessment of the chemical and mineralogical composition

The chemical and mineralogical composition is the determining factor for choosing the direction of waste use. For an objective assessment, it is necessary to determine:

Organic and mineral part;

Type of organics (oils, resins, tar, plant residues, etc.);

In the mineral part, in addition to the content of basic oxides (SiO2, Al2O3, Ge2O3, GeO, CaO, MgO, etc.), it is also necessary to determine the elemental (qualitative) composition in order to identify the presence of rare earth metals.

According to the ratio of the organic and mineral parts, all wastes are divided into organic, organo-mineral and mineral. Computer method for assessing mineral raw materials for the production of building materials by Professor V.I. Solomatova allows you to determine the qualitative composition of the diagram Si02-A1203-(R1R2)0. The evaluation is carried out according to the chemical composition of the raw materials, the amount of eutectic melt and the ratio between the melts. Keeping in mind - also, the frequent variability of the chemical composition of technogenic raw materials, it is advisable to extend this method to determine the degree of mineralization of such raw materials.

Rice. 2. Diagram of SiO2-Al2O3(R1R2) O. Regions of chemical composition

technogenic raw materials: 1 - silica, 2 - alumina, 3 - aluminosilicate, 4 - alkali-containing, 5 - alkali-silicate, 6 - alkali-aluminate, 7 - alkali-aluminosilicate.

IV stage - Volume of education.

The volume of generation (large-, low-tonnage) determines the use of waste in the form of the main raw material, or as additives.

Industrial waste, after a phased assessment, acquires a certain status that allows builders to use it in the production of building materials.

However, when preparing technogenic raw materials for the production of building materials, it is necessary to take into account the laboriousness of the process.

extraction of a valuable component from waste or its purification from toxic impurities.

Therefore, all costs for the processing of technogenic raw materials for its transformation into conditioned raw materials are preliminarily taken into account.

All this determines the economic efficiency of using waste for the production of cheap building materials.

All the necessary information for the further use of technogenic raw materials is developed by specialists of special services. This contributes to a serious solution of the problem of waste accumulation and improvement of the environmental situation.

3. Ecological and hygienic requirements in the production of building materials

For the purposes of environmental and hygienic safety at enterprises (1) must:

A regulatory and technical set of documents on labor safety when working with finely dispersed waste from various industries should be developed;

Apply a technological method for the manufacture of materials, for example, concrete, which maximally excludes the contact of working people with fine waste;

Maintain an indicator of the parameters of technological equipment

vaniya, providing the required concentration of harmful substances in the air of the working area;

Careful control over the content of harmful substances in the air of the working area of ​​the enterprise's workshops was organized;

The enterprise provides for the procedure for providing working people with personal protective equipment against dust, noise and vibration;

Regular medical and preventive examination of workers who have contact with production waste is carried out;

Controlled by a state document on the compliance of an enterprise for the production of concrete of various types based on man-made waste to all sanitary and hygienic requirements;

A duly approved list of requirements for the presence of all substances that make up concrete, toxicological characteristics and their compliance with the requirements for the content of NRN;

Any case of the possibility of operational and climatic impact, leading to the release of harmful substances above hygienic standards and causing the materials to become allergenic, carcinogenic and other hazardous properties, is excluded.

For example, concrete is considered environmentally friendly if it meets the requirements for the content of natural radionuclides and the release of harmful substances into the atmosphere under different operating conditions in accordance with the current MPCs.

LITERATURE:

1. Gusev B.V. and others. The use of solid waste foundry production in the construction industry. Ecology and Industry of Russia, No. 2, 2005 p. 12-15.

2. A.I. Zvezdov, L.A. Malinina, I.F. Ru-denko. Concrete technology in questions and answers. M., 2005.

3. B. A. Usov, A. N. Volgushev. Technology of modified sulfur concretes. M., MGOU publishing house, 2010.

One of the main environmental problems in the production of construction The production of materials is associated with huge volumes of production, extraction and processing of more than 2 billion tons of natural materials. Associated with this is widespread expropriation, disturbance, and pollution of agricultural land, since raw materials for building materials are usually mined as close to the construction area as possible to reduce transportation costs. And areas of intensive construction are densely populated areas that are convenient for growing crops. One of the ways to solve the problem is to recultivate disturbed lands, build ponds at the site of quarries and use them for cultural purposes, fish farming, etc.

The general direction is the use of waste from mining and processing industries as raw materials for the industry of building materials. According to tentative estimates, more than 3 billion tons of mining dumps are annually formed in the country, including all the main components of the raw materials used in the production of building materials. Only 6-7% are used, and most of them are used for planning territories, backfilling roads and, to a much lesser extent, for the production of building ceramics and other building materials.

Only blast-furnace slags were widely used in the production of building materials. Of the 37 million tons of blast-furnace slag sold (14 million tons went to dumps), 26 million tons were granulated and the bulk was used to produce Portland slag cement, 6 million tons were processed into slag pumice, cinder blocks, mineral wool, crushed stone and other materials, and about 5 million tons were transferred to construction and other organizations for direct (without pre-treatment) use as an additive to concrete, for heat-insulating backfills, for laying road foundations, for producing local binder, etc.

According to research institutes, about 67% of overburden rocks are suitable for the production of building materials. Of this amount of waste, 30% is suitable for the production of crushed stone, 24% for cement, 16% for ceramic materials and 10% for silicate materials.

In general, the building materials industry, like no other industry, can and should organize its raw material base at the expense of waste from the mining and processing industries of the national economy. In the meantime, the use of KMA overburden does not exceed 8% (although in this case, the economic effect of their sale increases annually).

Another major environmental problem enterprises of the construction industry is a significant dust emission, especially in factories for the production of cement. Approximately 20% of the cement produced is thrown into the chimney if the dust removal is not working. Most dust is emitted with exhaust gases from rotary kilns. Along with this, dust is released in large quantities during crushing, drying and grinding of raw materials (not only in the production of cement, but also in the production of ceramics, glass and other building materials), as well as during cooling of clinker, during packaging, during loading and unloading operations. in warehouses of raw materials, coal, clinker and various additives.

To reduce the formation and release of dust, primarily by reducing fugitive emissions, it is necessary to ensure complete sealing of production units and vehicles and create a vacuum inside the apparatus. To reduce dust formation, in addition to sealing factory equipment, it is advisable to reduce the fall height of dusty materials, moisten the poured and transported materials. All gases sucked out by smoke exhausters from rotary kilns and drying drums, as well as air taken from ventilation units, are sent to dust collectors. Here, dust is released from them, which is returned to production, and the purified gases are emitted into the atmosphere and must comply with sanitary standards. The plants provide for air extraction from all dust-forming units, including bunkers, chutes, crushers, conveyors, etc. Natural and forced ventilation is organized in the premises.

42. "Environmentally friendly" technologies of food industries. The problem of ecological food safety. Environmentally friendly food packaging materials.

Ecologically safe food products are products obtained from environmentally safe raw materials using technologies that exclude the formation and accumulation of chemical and biological substances potentially hazardous to human health in products and that meet medical and biological requirements and sanitary standards for the quality of food raw materials and food products. Food safety is guaranteed by establishing and maintaining regulated levels of any contaminants. The central link in the food safety system is the organization of control and monitoring of their contamination.

Monitoring objectives:

Determination of the initial level of contamination of food products with toxicants and the study of the variability of these levels over time;

Determination and confirmation of the effectiveness of measures to reduce the level of food contamination with foreign substances;

Ensuring constant monitoring of the degree of contamination of food products, not allowing the established MPC to be exceeded.

According to the degree of intensity of the negative impact of food industry enterprises on environmental objects, water resources occupy the first place.

In terms of water consumption per unit of output, the food industry occupies one of the first places among the branches of the national economy. The high level of consumption causes a large volume of wastewater generation at enterprises, while they have a high degree of pollution and pose a danger to the environment. The discharge of sewage into water bodies quickly depletes oxygen reserves, which causes the death of the inhabitants of these water bodies.

The most harmful substances, entering the atmosphere from food industry enterprises - organic dust, carbon dioxide, gasoline and other hydrocarbons, emissions from fuel combustion. The problem of atmospheric air protection for processing enterprises is also relevant.

The composition of wastewater makes it possible to use it for irrigation of agricultural crops, which solves the problems of cleaning and increasing soil fertility. However, this process is expensive, complex and not efficient enough (wastewater treatment is 35-90%).

A radical solution to the problem is the use of wasteless production. This direction is the main one in improving the water management of enterprises.

Eco-friendly product packaging.

Package- items, materials and devices used to ensure the safety of goods and raw materials for movement and storage (containers); also the process itself and a set of measures to prepare subjects for it.

After the Second World War, the forced development of new materials began, primarily polymers. Industrial production has been mastered: polystyrene (by the method of thermal polymerization); polyethylene, including high and low pressure (LDPE and HDPE); polyvinyl chloride (PVC); polyethylene terephthalate (PET).

Cardboard packaging, as before, remains one of the most popular types of packaging material and is used in a variety of industries. It is by the packaging, first of all, that the buyer of this or that product judges, which means that it must be done at a decent level.

Corrugated board presents is a high-quality and versatile packaging material that combines such important qualities as high physical performance and more than affordable price.

Today, corrugated packaging and corrugated cardboard are in high demand among Russian manufacturers, ordinary citizens are sometimes faced with the need to buy a corrugated box, corrugated tray or corrugated box, because such types of packaging perfectly protect fragile things, for example, when moving. Corrugated packaging preserves fruits and vegetables well, perfectly protects electronics and household appliances

Parameters: Low price, practicality, reliability. But the environmental factor is also important. Only environmentally friendly materials can ensure the safety of certain types of products.

Another important point is strength characteristics. Corrugated cardboard this is a material consisting of several wavy and straight sheets that replace each other: this structure allows the material to provide excellent cushioning properties and sufficient rigidity, which distinguishes it favorably from packaging materials with similar parameters. Corrugated cardboard is ideal when high impact, pressure and compression resistance is required from the material. Depending on the requirements for resistance to external influences, the plant produces corrugated packaging using from two to seven successive straight sheets of cardboard and corrugations.