Статья опубликована в рамках: Научного журнала «Студенческий» № 19(231)
Рубрика журнала: Технические науки
Секция: Архитектура, Строительство
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THE USE OF GLASS WASTE IN THE PRODUCTION OF BUILDING MATERIALS
ИСПОЛЬЗОВАНИЕ СТЕКОЛЬНЫХ ОТХОДОВ В ПРОИЗВОДСТВЕ СТРОИТЕЛЬНЫХ МАТЕРИАЛОВ
Боев Сергей Романович
студент, Национальный Исследовательский Московский Государственный Строительный Университет
РФ, г. Москва
Кондратьева Елизавета Александровна
студент, Национальный Исследовательский Московский Государственный Строительный Университет,
РФ, г. Москва
Юдина Ирина Ивановна
преподаватель, Национальный Исследовательский Московский Государственный Строительный Университет,
РФ, г. Москва
This article deals with the issue of recycling glass waste and the manufacture of new building materials from them; it gives a description of the processes of production of new building materials and the examples of the operational characteristics of these materials, taking into account their advantages and disadvantages.
Данная статья затрагивает вопрос утилизации стекольных отходов и изготовления из них новых строительных материалов; даётся описание процессов производства новых строительных материалов, приводятся примеры эксплуатационных характеристик данных материалов, с учётом их преимуществ и недостатков.
Keywords: glass fight, foam glass, recycling, building materials, ceramics, recycling, charge, production process.
Ключевые слова: стекольный бой, пеностекло, переработка, строительные материалы, керамика, утилизация, шихта, процесс производства.
The number of new construction companies in Russia is increasing every year. The number of new capital and housing construction projects is also constantly increasing. Such a situation on the market requires a constant increase in the growth of production of building materials, which must meet modern criteria: durability, strength, relative cheap cost have good thermal insulation properties.
In the construction materials industry, materials made from recycled materials, in particular from glass industry waste, are increasingly being used.
Glass fighting is, first of all, a valuable raw material. It can be introduced into the composition of the charges of various ceramic products. This will significantly reduce the part of raw materials, many of which (for example, soda ash) are expensive and rare. Due to the content of cullet, the charge greatly reduces the use of energy during the firing of ceramics, since the glass is fused faster.
A huge number of building materials are also made on the basis of glass fighting. These include: foam glass, glass-silica, foam concrete, self-glazing ceramics, perlite-silica, fiberglass-silica, foam-glass-crystalline materials, etc. Let us list the main advantages of all these materials.
Foam glass is a vitreous material permeated with many uniform pores. Its main properties are low water absorption, low volume weight, low coefficient of thermal conductivity. In appearance, foam glass can be completely different: painted, colorless, coated with glaze for facing facades of buildings. It is produced in the form of plates of different sizes. The raw material for the production of foam glass is glass production waste - cullet and erklez, which are pre-subjected to coarse crushing in a jaw crusher, and then finer grinding in a hammer mill.
The production process of foam glass begins with the production of a charge consisting of 97 percent crushed glass and 3 percent of gas-forming agents (such as limestone, carbon, charcoal, coke, soot), followed by its heating to a temperature of 850-875 degrees Celsius. At this temperature, the glass grains are sintered with each other, and the gases that are formed as a result of the decomposition of additives of gas-forming agents foam the highly viscous glass mass. After the mass is annealed and cooled, a thermal insulation material with high mechanical strength is obtained. In modern production, foam glass is improved by introducing sodium hydroxide into the composition. To do this, the cullet is crushed to very small particles (0.5-0.1 millimeters). Then a foaming mixture is prepared. This is done by adding a 20 percent sodium hydroxide solution to the glass powder. The consumption of sodium hydroxide should be 1-4 percent of the weight of the glass powder. After all the procedures, the mixture is kept for 50-70 hours then it is dried to a humidity of 5-8 percent. From the resulting mixture, raw granules with a diameter of 5-10 millimeters are obtained, which are treated with a solution of nitric acid, dried again and foamed at 850-875 degrees Celsius in a rotating furnace.
Foam glass has high performance characteristics: it is durable, has low thermal conductivity, non-flammable, non-toxic.
Foam glass is an excellent thermal insulation material. The organization of foam glass production helps to effectively solve the problem of cullet recycling.
Another material produced from glass waste is glass silica for construction purposes. It is a decorative finishing material. The process of its production begins with a special preparation of cullet and its subsequent granulation, for introduction into the composition of working mixtures. To obtain the glass granulate, the glass fight is crushed in a crusher, separating a fraction of 1-5 millimeters, since the cullet of such a fraction is usually illiquid for use by glass factories. Various inclusions, labels, metal and ceramic inclusions are separated during the processing of glass into glass granulate. Then the mixture is sintered in an oven at 850-970 degrees Celsius, after which it is crushed to obtain the glass granulate of the required fraction.
This is followed by the process of obtaining glass silica. To do this, a 3 mm layer of quartz sand is poured into a ceramic refractory mold, followed by a layer of a moistened mixture of quartz sand and glass granulate, in a ratio of 1 to 5 with a thickness of about 10 millimeters (the amount of water is not more than 5 percent by weight). In the remaining part of the mold there is a layer of colored or colorless glass granulate mixed with a dye. Then the molds are subjected to heat treatment in a furnace, after which the glass-silica tiles are removed from the molds.
In this method of glasscremsenite production, the use of granular glass waste in the working mixture reaches 60-75 percent. Due to the use of granular cullet, rather than silenced glass granulate the cost of the material is greatly reduced.
Glasscremsenite is usually produced in the form of slabs with a thickness of 10-20 millimeters and an area of 100-150 square centimeters. It is an excellent decorative facing material for finishing both internal and external walls.
Another building material made from glass waste is carpet-mosaic tiles. These plates find their application in the decoration of buildings and structures, in interior and exterior decoration. They are made by rolling or pressing cullet, crushed to very small fractions. The cullet can be absolutely anything: colored, white, colorless. Sand is also, added to the mixture as a filler. The most economical and fastest way to produce carpet-mosaic tiles will be pressing, since it is in it that the cullet is used in the basis. The pressing process itself is much faster compared to the analog, and the fuel consumption in it is lower than if the tiles were made by cooking in a glass oven and then rolled.
With the help of cullet, a special type of ceramics is also produced – self-glazing facing ceramics. The main function of cullet in it is the role of a flux-strengthening additive, which serves to increase the strength and reduce the water absorption of the material. Additionally, a melt is introduced into the composition of the charge, which acts as boric acid and polymer waste, acting as a burn-out additive to increase porosity and reduce the thermal conductivity of the material.
Self-glazing ceramics are produced by semi-dry pressing. For the production of the charge, a mixture of low-plastic clay and waste is used in the ratio of 60 percent clay, 40 percent waste. The mixture is crushed a fraction with particles no larger than 0.5 millimeters is selected and dried to a constant mass. Then, 8 percent (of the total weight) is added to the finished dry mixture water and mix until a homogeneous molding substance is obtained. After that, the mixture is evenly distributed over the molds and put under a press with a pressure of 17 megapascals, followed by firing at a temperature of 1000-1100 degrees Celsius. At the end of all production procedures, the plates are removed from the molds.
Due to the use of glass fighting in the material, its strength becomes greater. This is due to the fact that the cullet in the material, when heated, forms a strong frame of ceramic particles that are interconnected by layers of glass - the vitreous phase. The presence of boric acid causes an increase in the amount of the formed vitreous phase and reduces the temperature of the beginning of its formation. When these components are added, water absorption decreases. This is due to the fact that the forming vitreous phase fills most of the pores and voids in the material. At the same time, the remaining pores move from open to closed, or their size decreases to the size where water does not penetrate.
Cullet is used in building materials not only as the main component, but also as a special additive. An example of the successful use of such an additive is the addition of a glass fight to a brick. If the cullet in the charge is 40-50 percent, then the temperature of the kiln can be lowered from 1170 degrees Celsius to 880 degrees Celsius. At the same time, the furnace capacity will increase by 35 percent, and fuel use will remain the same. The most high-quality bricks with this method will be from a mixture: 30 percent glass fight, 50 percent brick waste, 20 percent clay. Such bricks are durable and unpretentious they can withstand extreme weather conditions. Their only disadvantage will be a relatively large thermal conductivity.
Glass waste is suitable for improving the properties of paints. When glass powder is introduced into the paint, it increases such parameters as: chemical resistance, resistance to mechanical abrasion.
Glass powder is also an excellent additive for rubber. Its addition increases the abrasive resistance and hardness. Also, glass powder can be a strengthening filler for plastics. The most effective in all cases is the addition of fine glass powder.
Cullet can be used as, a filler for polyester resins. Complex parts, such as flanges, can be obtained from such a mixture. To do this, take a cullet with a diameter of 0.11-0.13 millimeters. Such particle size limits are chosen specifically to obtain the best value of tensile and compressive strength. They are usually 1270 and 400 kilograms per centimeter. This is marginally lower compared to using fiberglass. But in most cases, the quality of products suits consumers, since parts with glass chips are much cheaper to produce than with fiberglass. Technologically, the process of manufacturing such fiber parts is more labor-intensive and time-consuming. To achieve a thickness of 10-12 millimeters, it is necessary to lay 20-25 layers. Between the layers, in order to remove the heat of the hardening polyester resin, it is necessary to make extracts.
Another advantage of products with glass chips over fiberglass products is their water resistance. Since the particles are located separately from each other, the material practically does not pass water, unlike the fiberglass material. It's all about diffusion: water penetrates into the part along the fibers, from where it is very difficult to extract it. When combined with cullet polymers or cements, it can be used for the manufacture of floor slabs by pressing.
The color and appearance of the tiles is regulated by the addition of dry or liquid dyes to the not yet solidified composition. Due to the absorption of dye molecules on glass particles, the color becomes more stable, it can no longer be removed by exposure to water or ordinary solvent. The surface of the tiles is set primarily by the texture of the shape itself. It can be grooved, rough, matted. If the tiles are used for wall cladding, they can be sanded after pressing. Such tiles are used for covering the floor and lining the walls of industrial structures.
To do this, they have all the necessary characteristics: strength, resistance to abrasion and scratching, cheapness, slip resistance, which is especially important for the floor of an industrial building. The slip coefficient is measured in conventional units. For industrial buildings, it is divided into the following categories: 29 and below – dangerous unusable, 30-49 – the lower permissible limit, 50-65 normal values, 66-79 good values, 80-100 – very good. The resistance of concrete tiles with the addition of cullet reaches values from 75 to 100.
Another application of the cullet was found in a solution for bonding foam glass slabs and blocks. A finely ground powder is obtained from it (the particle size should be less than 0.05 millimeters), to which binders in the form of silicic acid and an inert filler are added. Quartz sand or large glass waste that does not enter into a strong chemical reaction with the binder can serve as, a filler. The blocks on this solution have bending strength, heat resistance and increased mechanical strength.
But the most important way of recycling glass waste remains its reuse in glass cooking. The introduction of cullet into the composition of the charge up to 85-95 percent greatly saves raw materials and reduces the heating temperature of the furnace.
In conclusion, it should be said that the disposal of cullet solves a large number of production problems, improves the environmental situation, and is a source of many valuable building materials.
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