RU2520978C2 - Charge for production of silicate glass - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to compositions of charges for production of glass and can be used for manufacturing products of industrial and decorative-artistic purpose, as well as in production of ceramic products. A charge for production of silicate glass is obtained by mixing wastes of trotyl and nitrobenzene production - a mixture of trotyl and nitrobenzene mother liquor and their cinder with silica, chalk, dolomite, kaolin, accelerating, reducing and clarifying additives with the following component ratio, wt %: quartz sand 42.4-45.6; chalk 1.0-1.2; dolomite 10.2-10.5, kaolin 2.3-2.5; cinder of trotyl and nitrobenzene mother liquor 28.5-30.8; mixture of trotyl and nitrobenzene mother liquors, solid substance 10.8-11.8; coal 1.2-1.4. The charge melting is performed at 1350-1400°C.

EFFECT: improvement of the environment ecology; increased quality and reduction of cost of silicate glass production due to utilisation of wastes of trotyl and nitrobenzene production.

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Description

The invention relates to compositions of mixtures for producing colorless, colored in mass and other types of glasses, and can be used for the manufacture of products for industrial and decorative purposes, as well as in the manufacture of ceramic products.

The raw materials used for the manufacture of glass are divided into main and auxiliary. The main raw materials include substances with the help of which acid, alkali and alkaline earth oxides are introduced into the glass, which are the basis of the composition of modern glasses. Auxiliary raw materials include various substances that are used to improve the quality of glass melt, dye it and extinguish it, and also to accelerate the time of its manufacture (Butt L.M., Polyak V.V. Glass technology. - M .: State ed. in the literature on construction, architecture and construction, 1960, p. 67).

The basis of the chemical composition of silicate industrial glasses - window, architectural, construction, packaging and others - are various combinations of oxides of Na ₂ O, CaO, SiO ₂ . In addition, to reduce the tendency to crystallization and increase the chemical resistance of glasses, magnesium and aluminum oxides are additionally introduced into their composition. So, for example, back in the mid-30s II. Kitaygorodsky developed and introduced into the industry alumina-glass composition, wt.%: SiO ₂ 71.5-72; Al ₂ O ₃ 1.5; CaO 8-8.5; Na ₂ O 15; MgO 3,5 (Chemical technology of glass and glass materials. Artamonova M.V., Aslanova M.S., Buzhinsky I.M. et al. / Edited by N.M. Pavlushkin. - M., Stroyizdat, 1983, p. .211).

Sodium carbonate or sodium sulfate is used to introduce sodium oxide into the glass. In this regard, there are two options for glass blends containing sodium sulfate.

Sulfate charge - sodium oxide in whole or in an amount of more than 25% is introduced into the charge using sodium sulfate (Chemical technology of glass and glass metals. Artamonova M.V., Aslanova M.S., Buzhinsky I.M. et al. / Ed. N.M. Pavlushkina. - M., Stroyizdat, 1983, p. 106). However, the process of making glass from a sulfate charge becomes longer and requires higher temperatures. In this case, in order to accelerate the process of silicate formation and reduce the temperature, pre-decomposition of sodium sulfate to sodium oxide is resorted to. To do this, a certain amount of carbon-containing materials is introduced into the glass charge - coal or charcoal, sawdust or shavings (Glass Technology. Butt L.M., Polyak V.V. - M., State Publishing House of Literature on Construction, Architecture and construction, 1960, p.64) or any organic substances (P.N. Grigoriev, M.A. Matveev. Soluble glass (preparation, properties and applications). - M .: State ed. of literature on building materials, 1956, 444 pp.), Acting as sodium sulfate reducing agents. A method of producing glass from a sulfate charge is resorted to if it is necessary to reduce the cost of production, since the original sodium sulfate is a cheap substitute for soda. The disadvantages of producing glass by the sulfate method are the complexity of the process, the need to use carbon-containing materials, reducing the quality of the products and the need to heat the mixture in the manufacture of ordinary glasses to 1500-1600 ° C (Chemical technology of glass and glass materials. Artamonova M.V., Aslanova M. S., Buzhinsky I.M. et al. / Under the editorship of N.M. Pavlushkin. - M., Stroyizdat, 1983, p.105).

Closest to the proposed invention (prototype) is a carbonate-sulfate mixture, currently used to produce glass. In this case, 80-95% sodium oxide is introduced into the molten glass using soda ash, the rest with sodium sulfate, which plays the role of a clarifier (Chemical technology of glass and glass metals. Artamonova M.V., Aslanova M.S., Buzhinsky I.M. . and others / Under the editorship of N.M. Pavlushkin. - M., Stroyizdat, 1983, p. 106). The main disadvantage of making glass from such a mixture is the relatively high cost of soda and its scarcity, since soda is a raw material that has huge demand from various industries (Kukushkin Yu.N. Chemistry around us: Reference book. - M .: Higher school ., 1992, p. 46), and the need to use additional carbon fuel.

The technical result, the solution of which the invention is directed, consists in the utilization of wastes from the production of TNT and nitrobenzene, improving the quality of glass and reducing the cost of its production.

The technical result is achieved by the fact that in a charge for producing glass, including quartz sand, calcium-containing and alkali-containing components, accelerating, clarifying and reducing additives, alkali-containing components, accelerating, clarifying and reducing additives use a mixture of wastes from trotyl and nitrobenzene production - a mixture of mother liquors from trotyl production and nitrobenzene, and their cinder, in the following ratio of components, wt.%: quartz sand 42,4-45,6; chalk 1.0-1.2; dolomite 10.2-10.5; kaolin 2.3-2.5; cinder of mother liquors of trotyl and nitrobenzene 28.5-30.8; a mixture of mother liquors of TNT and nitrobenzene 10.8-11.8 (30-40% solution), coal 1.2-1.4, and the charge is melted at 1350-1400 ° C.

The production of energy-intensive compounds, such as TNT and nitrobenzene, is accompanied by the formation of a significant amount of waste. So, for example, during the purification of raw trotyl (E.Yu. Orlova. Chemistry and technology of blasting explosives. - Chemistry, 1973. - 688 p.), Tens of thousands of tons of sulfite liquor, the mother liquor for the production of trotyl, containing sodium salts of sulfonic acids of asymmetric isomers TNT, nitrophenols, nitro acids, nitrite and sodium nitrate, soda, sodium sulfate and sodium sulfite, sulfide and sodium chloride.

Hydrolysis of sodium salts present in sulphite liquor leads to the fact that the pH of its solution rises to 9.0-9.5, which corresponds to slightly alkaline environments.

Often, the production of TNT and nitrobenzene are located at the same enterprises.

After receiving nitrobenzene, it is separated from the nitrating mixture of acids (nitric and sulfuric), and then washing with ammonia water. The nitrobenzene production mother liquor contains about 8-10% of organic (nitro derivatives of benzene) and inorganic compounds dissolved in water, the main of which is ammonium sulfate.

According to the current regulations, the neutralization of the toxic mother liquor of nitrobenzene production is allowed to be carried out together with sulfite liquors of TNT production. For this, the mother liquor of nitrobenzene is drained into the storage with the mother liquor (sulfite liquor) of TNT. According to the technology currently adopted, the mixture of mother liquors of trotyl and nitrobenzene after preliminary evaporation to a 30-40% concentration by solid residue is sent to incineration, and the resulting ash is dumped. Under the influence of precipitation, it turns into toxic effluents that pollute groundwater, which leads to a significant deterioration of the ecological situation.

Disposal of large-scale chemical production wastes by using them in the production of glass improves the environmental situation in the areas of TNT and nitrobenzene production and significantly reduces the cost of glass production.

The process of preparing the mixture and making glass according to the invention is as follows. Waste from the production of energy-intensive compounds - a mixture of mother liquors from the production of TNT and nitrobenzene after chemical analysis is mixed with the required amount of silica. The introduction of water with the mother liquor solution into the mixture facilitates its hydration, which, along with the presence of weak alkalis in the solution, leads to the formation of a uniformly distributed film of alkaline compounds on the surface of quartz sand particles, and this, in turn, favorably affects the processes of silicate formation. In addition, the moistening of raw materials also has a beneficial effect on the homogeneity of the charge (Chemical technology of glass and glass. Artamonova M.V., Aslanova M.S., Buzhinsky I.M. et al. / Edited by N.M. Pavlushkin . - M., Stroyizdat, 1983, p.65). The temperature of the mother liquor should be 50-60 ° C. Silica prepared in this way is mixed with other ground components of the charge, one of which is solid waste from the production of TNT and nitrobenzene, a cinder of mother liquors of energy-intensive compounds. It is worth noting that, thanks to the existing technology for neutralizing the mixture of mother liquors for the production of TNT and nitrobenzene by burning, the cinder formed is a finely divided homogeneous composition that does not require additional grinding. A typical chemical composition of a calcine mixture of mother liquors of trotyl and nitrobenzene is given in table 1.

Table 1 The chemical composition of the cinder mother liquor of TNT and nitrobenzene Component The content of components,% Sodium sulfate 55.5 Sodium carbonate 24.6 Ammonium sulfate 9,4 Sodium chloride 8.0 Iron Oxide (Fe ₂ O ₃ ) 1,1 Carbon 1.3 Moisture 0.1 Quality response to TNT Positive

The resulting mixture is loaded into crucibles, which are fed into the furnace at a temperature of 1100-1200 ° C. Glass is melted in pot furnaces at a temperature of 1350-1400 ° C. Due to the presence of sodium, magnesium, and ammonium sulfate carbonates in the charge, chemical processes in the charge begin at relatively low temperatures (330-350 ° C).

At 780-880 ° C, the liquid phase appears due to eutectics of magnesium and sodium silicates with silica and double carbonic salts with Na ₂ CO ₃ (Chemical technology of glass and glass metals. Artamonova MV, Aslanova MS, Buzhinsky I. M. et al. / Under the editorship of N.M. Pavlushkin. - M., Stroyizdat, 1983, p. 107). However, the presence of various salts of sodium and ammonium (cooking accelerators) in the waste composition leads to the appearance of fusible compounds, the melts of which are formed earlier (Glass technology. Butt L.M., Polyak V.V. - M., State Publishing House of Literature on construction, architecture and construction, 1960, p.132-133).

The carbon (in the form of soot), which is present in the cinder (from 1.1 to 5%), as well as organic reducing agents introduced into the charge as part of the mother liquor of energy-intensive compounds and gaseous products of its decomposition CO, are directly involved in the reduction reactions of sodium sulfate, H ₂ , CH ₄ , etc., which create a reducing atmosphere in the mixture. In the case of a low soot content in the cinder, a carbon-containing material in the form of coal or sawdust is additionally introduced into the charge.

The recovery of sodium sulfate begins at 740-800 ° C according to the reaction:

Na ₂ SO ₄ + 2C = Na ₂ S + 2CO ₂

It is worth noting that the water present in the cinder and the mother liquor accelerates the formation of silicates. This is due to the formation of caustic soda, which interacts with silica more energetically than soda:

Na ₂ S + 2H ₂ O = 2NaOH + H ₂ S

2NaOH + SiO ₂ = 2Na ₂ SiO ₃ + H ₂ O

At 865 ° C, silicate formation processes begin:

Na ₂ SO ₄ + Na ₂ S + ₂ SiO ₂ = ₂ Na ₂ SiO ₃ + SO ₂ + S

CaO + SiO ₂ = CaSiO ₃

Clarification of the glass melt and its homogenization require an increase in the temperature of the glass melt to 1350-1400 ° C. The presence of sodium sulfate, sodium chloride and ammonium sulfate (up to 3%) (Handbook for the production of glass. / Under the editorship of I.I.Kitaygorodsky. A.I. Berezhnoy, Yu.A. Brodsky, Z.I. Bronstein and others. - M., State Publishing House of Literature on Construction, Architecture and Construction, 1963, p.160-162) in a mixture helps to accelerate the process of manufacturing glass melt, its clarification and homogenization, after which the student process is carried out when the temperature of the mass decreases (by 300-400 ° C) to the temperature necessary for the formation of products.

To assess the quality of the molten glass obtained on the basis of waste from energy-intensive compounds, laboratory experimental melting of glass blends was carried out under rather severe conditions: the maximum temperature of heating the glass melt was 1350-1400 ° C, and the exposure time of the molten glass melt at the maximum heating temperature was 35-60 min. Glass blends were designed to obtain silicate glass composition, wt.%: SiO ₂ 72,0; Al ₂ O ₃ 1.5; CaO 7.0; Na ₂ O 16.5; MgO 3.0. For comparison, glass melt of the same composition was made from soda and carbonate-sulfate blends prepared using traditional raw materials. The ratio of sodium sulfate and sodium carbonate in the carbonate-sulfate mixture corresponded to the content of these substances in the cinder of waste energy-intensive compounds.

Table 2 shows the composition of the experimental glass mixture to obtain aluminum-magnesian glass mass. The content of ammonium sulfate in the mixture was 2.7%, and sodium chloride - 2.3%, which, along with the presence of sodium sulfate in the mixture, is quite enough to effectively accelerate the glass manufacturing process, its clarification and homogenization.

table 2 The composition of the experimental glass mixture Charge component The content of the component,% Charge 1 Charge 2 Charge 3 Silica 42,4 43.8 45.6 A cinder of sulfite liquors and mother liquor of nitrobenzene 30.8 29.3 28.5 a piece of chalk 1,0 1,1 1,2 Dolomite 10.5 10,4 10,2 Kaolin 2,3 2,4 2,5 TNT and nitrobenzene mother liquor (solid) 11.8 11.6 10.8 Coal 1,2 1.4 1,2

The quality of the obtained glass was evaluated by its specific gravity, solubility in water, uniformity and color. The results are shown in table 3.

Table 3 Characteristics of glass samples Glass melt Specific gravity, g / cm ³ / exposure, min Solubility in water,% / exposure, min Uniformity Color Bottle glass 2.59 2,8 Homogeneous, with single bubbles Light green, uniform color Glass melt made using sulphate-carbonate technology 2,43 / 35 7.5 / 35 The presence of bubbles Pale green uniform color Glass melt made on the basis of nitrobenzene and TNT waste 2,58 / 35 (charge 1) 2,5 / 35 (charge 1) Homogeneous, with single bubbles Bright green, uniform, intense color 2.59 / 35 (charge 2) 2.1 / 35 (charge 2) 2.62 / 60 (charge 3) 1.94 / 60 (charge 3)

Table 3 for comparison shows the results of assessing the quality of regular bottle glass used for bottling mineral water. As can be seen from the results obtained, the use of waste from the production of energy-intensive compounds improves the quality of the resulting glass melt while reducing the maximum melting temperature of the mixture.

The total content of TNT waste in the experimental mixture used to produce glass according to this invention is more than 40%, which significantly reduces the cost of the whole process and allows you to completely utilize TNT and nitrobenzene waste.

Claims (1)

A mixture for producing glass, including quartz sand, calcium-containing and alkali-containing components, accelerating, clarifying and reducing additives, characterized in that as alkali-containing components, accelerating, clarifying and reducing additives, a mixture of wastes from the production of trotyl and nitrobenzene is used - a mixture of mother liquors from the production of trotyl and nitrobenzene and their cinder, in the following ratio of components, wt.%: silica sand 42.4-45.6; chalk 1.0-1.2; dolomite 10.2-10.5; kaolin 2.3-2.5; cinder of mother liquors of trotyl and nitrobenzene 28.5-30.8; a mixture of mother liquors of trotyl and nitrobenzene, a solid substance of 10.8-11.8; coal 1.2-1.4, and the charge is melted at a temperature of 1350-1400 ° C.