RU2497771C1 - Raw material mixture for production of silicate brick - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to industry of building materials, namely to production of silicate brick. Raw material mixture for production of silicate brick contains wt %: quartz sand 67, lime 8, waste, accumulated in dust-collecting systems in drying of clayite granules and representing powder-like material, clayite dust with specific surface area 670 m²/kg, 25.

EFFECT: increase of air brick strength, improvement of mouldability, increase of strength, frost resistance, coefficient of softening.

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Description

The invention relates to the construction materials industry, namely the production of silicate brick.

In the building materials industry, raw materials are widely used for the manufacture of silicate bricks, which include, in certain proportions, pure quartz sand and air lime.

The known composition of silicate brick from a mixture of quartz sand (92-94% by weight of the dry mixture) and quicklime or hydrated lime (6-8) [L. Havkin Technology of silicate brick / L.M. Khavkin. - M., 1982. - S.108-114]. A disadvantage of the known technical solution is the low strength of the finished product. In addition, currently manufactured silicate products have high water absorption and water saturation, which leads to fragility. In recent years, there has been a significant increase in interest in the use of by-products and industrial wastes in the production of building materials, and this path is promising and relevant, as it allows solving not only technical, economic, but also acute environmental issues. A known composition of the manufacture of silicate brick from a semi-product of alumina production of petroleum sludge [US Pat. 2059588 Russian Federation. A method of producing silicate brick / Sizyakov V.M., Korneev V.I .; applicant St. Petersburg State University named after G.V .. 09/06/1995]. The disadvantage of this composition is the impossibility of obtaining a brick of a strength grade above M150.

The closest analogue to the proposed invention, adopted as a prototype, is a composition based on quartz sand, lime, clay salt sludge and ash additives [A.S. 660954 USSR. A method of obtaining silicate brick / Kisel I.I., Mazurenko V.D .; applicant Belarusian Technological Institute named after S.M. Kirov. - declared. 05/05/1979.], Which can significantly increase the strength. The disadvantages of this composition are the high cost of time, electricity and steam for autoclaving, low frost resistance and thermal properties of silicate brick.

The essence of the invention is to increase the physico-mechanical and aesthetic characteristics of silicate brick, reduce the energy intensity of production through the use of technogenic raw materials, reduce the consumption of lime-siliceous binder and reduce the parameters of autoclave processing (pressure during autoclaving from 10 to 6 MPa).

The technical result of the invention is to increase the raw strength and, as a consequence, improve formability, reduce rejects during production and obtain products with a clear geometry, increase compressive strength, frost resistance, softening coefficient, as well as improve aesthetic characteristics.

The technical result is achieved due to the fact that the raw material mixture, in addition to calc-siliceous binder and quartz sand, contains waste that accumulates in dust-collecting systems at the stage of drying expanded clay granules and is a finely dispersed material - expanded clay dust.

The waste under consideration is an aluminosilicate technogenic raw material formed at the stage of drying granules at a temperature of 400-500 ° C and representing a fine powder material with a specific surface of about 670 m ² / kg.

The initial rock for the production of expanded clay gravel is clay of the Yastrebovskoye deposit, which is characterized by a high content of silica. Analysis of the mineral composition of clay and claydite production wastes showed that the aluminosilicate raw material formed at a temperature of 400-500 ° C is represented by incomplete structural formation phases, and, unlike the initial rock, contains glass phase (Table 1).

Table 1 Title Content% Illitmontmorillonite Quartz Glass phase Clay 59.9 40.1 - Expanded clay dust 51,2 39.3 9.5

Expanded clay dust is introduced instead of part of the sand in the following ratio of components, wt.%:

lime 8

silica sand 67

expanded clay dust 25

table 2 Characteristics of quicklime Indicator Value Active CaO + MgO content, not less 80% Active MgO, no more 5% СО ₂ , no more 5% Unextinguished grains, no more eleven% The content of hydrated water, not more 2% Extinguishing time, no more 8 min

Table 3 The chemical composition of quartz sand SiO ₂ Al ₂ O ₃ SO ₃ Fe ₂ O ₃ Cao MgO K ₂ O + Na ₂ O ppp 93.02 0.92 0.02 0.98 0.62 0.08 0.46 0.86

Sand meets the requirements of GOST 8736-93 "Sand for construction work. Technical conditions. "

The introduction of waste claydite production into the mixture helps to increase the raw strength of silicate brick 3.4 times. This is due to the fact that the developed surface of expanded clay dust determines the increase in the number of contacts between particles during compaction and the associated increase in adhesion and mechanical engagement. This will improve the formability of the raw material mixture, reduce rejects during molding and will produce highly efficient multi-hollow products with a clear geometry.

In samples using expanded clay production waste steamed at a pressure of 6 MPa, a decrease in the size of neoplasms is observed in comparison with control samples made according to the traditional recipe and technology, which contributes to an increase in the number and area of contacts between individual crystals of neoplasms in intergrowths and with grains filler, providing good adhesion and durability of products. This, in turn, is explained by the high dispersion of dust, which determines its rapid activation in the CaO-SiO ₂ -H ₃ O system, and contributes to the formation of polymineral neoplasms with an optimal ratio of low and high basic calcium hydrosilicates, which increase the frost and water resistance of autoclaved pressed products, while reducing energy and material costs by 40%, and an increase in the strength characteristics of products by 100%.

In addition to improving the physico-mechanical characteristics, the introduction of expanded clay production wastes contributes to giving a stable color.

Examined claydite production wastes have a dark brown color, which affects the color of the samples. Color saturation increases with an increase in the content of expanded clay dust in the mixture and a decrease in the CaO _act content. The color of the samples does not change after they undergo hydrothermal treatment at elevated pressure.

An example of the composition and physico-mechanical properties of the proposed raw material mixture for the manufacture of silicate brick are shown in the table in table.4.

Claims (1)

A raw material mixture for the manufacture of silicate brick, containing quartz sand and lime, characterized in that it contains waste that accumulates in dust-collecting systems when drying expanded clay granules, which is a powdery material - expanded clay dust with a specific surface of 670 m ² / kg, in the following ratio of components, wt.%:
lime 8 quartz sand 67 expanded clay dust 25.