RU2326841C2 - Method of obtaining granulate for making foam glass and foam glass crystal materials - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: fraction of high-silica raw materials is prepared with percentage mass content of SiO₂ of more than 60% through heating at 200-450°C. Calcium carbonate with percentage mass content of 12-16% is then added. The obtained mixture is condensed in a mould made from heat-resistant steel. The mould is put into a continuous running furnace and is thermally treated at maximum temperature for 10-20 minutes, and the obtained sinter is ground up.

EFFECT: design of a method of obtaining a granulate used for making foam glass crystal materials without boiling the glass.

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Description

The invention relates to the field of technology of foam silicate materials obtained by foaming at temperatures above 800 ° C - foam glass, expanded clay, petrozites, including penoceolites, and can be used for the manufacture of heat-insulating materials with a density of 150-350 kg / m ³ . Before foaming the initial mixture, granulate or granules are obtained, which in some cases are crushed to a powder with a specific surface of 6000-7000 m ² / g.

A known method of producing granules for foaming by molding plastic masses on screw or roller presses, followed by drying at a temperature of 100-120 ° C, while foaming of the material proceeds at temperatures of 1180-1200 ° C. The disadvantage of this method is the limited applicability - only for clay-containing blends upon receipt of granular porous material (Onatsky S.P. Production of expanded clay. - M .: Stroyizdat, 1987). Obtaining the initial foaming mixture, for example, from cullet, this method is impossible.

A known method of producing glass granulate by mixing the components of the mixture of the required composition and melting the glass at temperatures above 1400 ° C, cooling the glass with subsequent crushing and grinding to a specific surface of 6000-7000 m ² / g (Kitaygorodsky I.I., Keshishyan T.N. Foam glass . - M., 1958; Demidovich V.K. Foam glass. - Minsk, 1975). The disadvantage of this method is the need to organize the process at high temperatures with high energy consumption.

Closest to the proposed solution in technical essence is a method for producing granulate, which includes preparing a fraction of high siliceous raw materials, adding soda ash, mixing powders and firing in continuous furnaces at a temperature of 750-850 ° C (Ivanenko V.N. Building materials and products made of silicon breeds. - Kiev: Budivelnik, 1978, pp. 22-25). The disadvantage of this method is the limited applicability - get thermoliths used as porous aggregates for concrete, which are made only of siliceous opal rocks (diatomite, tripoli, flask).

The objective of the invention is the preparation of granules based on heat treatment of a mixture of components: a) raw materials with SiO ₂ more than 60 wt.%, For example zeolite tuffs, marshallites, diatomites, tripoli, etc. and b) technological additives providing processes of silicate formation without glass melting.

The task is achieved as follows:

1. Siliceous rock containing SiO ₂ more than 60 wt.%, Crushed, crushed, sieved (fraction less than 0.3 mm);

2. Silica rock powder is activated by heating at a temperature of 200-450 ° C to remove the so-called "Molecular water";

3. To prepare the raw mix, add soda ash in an amount of 12-16 wt.%;

4. The resulting mixture is compacted in a form of heat-resistant steel and heat treated in continuous furnaces at a temperature of 750-850 ° C with exposure at a maximum temperature of 10-20 minutes;

5. The obtained cake is crushed to a fraction of less than 0.15 mm and is used to prepare a mixture with a blowing agent and other additives for the production of foam glass and foam glass materials by known technological processes.

The proposed method for producing granulate is illustrated by an example:

1. As a siliceous raw material, the zeolitized tuff of the Sakhaptinskoye field (Krasnoyarsk Territory) of the following chemical composition was used, wt.%: SiO ₂ - 66.1; Al ₂ O ₃ - 12.51; Fe ₂ O ₃ - 2.36; CaO - 2.27; MgO - 1.66; Na ₂ O - 1.04; K ₂ O - 3.24; TiO ₂ 0.34; loss on ignition - 10.28.

2. The prepared sample - crushed, sieved with a fraction of less than 0.3 mm, is activated by heating in an oven at a temperature of 400 ° C for 10 minutes.

3. The calculation of the amount of soda ash is carried out from the premises of the maximum formation of Na ₂ SiO ₃ during solid-phase interaction of SiO ₂ and Na ₂ CO ₃ - so per 100 g of activated sample, 18.62 g of soda ash is added.

4. For sintering using molds made of heat resistant steel. The inner surface of the mold is coated with kaolin slurry to prevent sticking from sticking to the metal.

5. The prepared powder mixture is compacted in a mold, placed in a muffle furnace and heated to a temperature of 800 ° C and held for 15 minutes.

6. The obtained cake with a glass phase content of 65-85% is cooled, crushed and is a semi-finished product for the preparation of a mixture for the production of foam glass.

The granulate obtained by this method is tested in the foam glass manufacturing process:

- the granulate was crushed to a fraction of less than 0.15 mm;

- a gasifier — coke, anthracite, liquid hydrocarbons in an amount of 1% by weight — was introduced into the obtained powdery mixture;

- the mixture was compacted in molds and thermally processed in a muffle furnace at a temperature of 820 ° C with a holding time of 15 minutes. After exposure, the molds were removed from the furnace to cool and stabilize the cellular structure.

Received foam glass material with the characteristics shown in the table.

Thus, the authors propose a method for producing granulate for the production of foam glass material, which allows the use of natural raw materials instead of scarce cullet. The technological process does not require high temperatures, which makes production cost-effective.

The main characteristics of the method and properties of foam glass material Type of granulate Processing Mode, Parameter Properties of foam glass crystallite Processing temperature, ° С The particle size of the granulate for the preparation of the mixture The temperature of the foam glass and foam glass, ° C Holding temperature, min The amount of glass phase, wt.% Density kg / m ³ Compressive strength, MPa Glass granulate (melt of a mixture of zeolite + soda) 1480-1500 ≥6000 cm ² / g 820 fifteen one hundred 300 08, -1.5 Solid phase sintering of a mixture of zeolite + soda 750 ≤0.15 mm 820 fifteen 65 350 3-4 Also 800 ≤0.15 mm 820 fifteen 70 300 2.5-3.5 Also 850 ≤0.15 mm 820 fifteen 80 300 2.5-3.5 Cullet 1500 ≥6000 cm ² / g 750-850 fifteen one hundred 150-200 0.8-2.0

Claims (1)

A method of producing granulate for the production of foam glass and foam glass materials, comprising preparing a fraction of high siliceous raw materials with a SiO ₂ content _of more than 60 wt.%, Adding soda ash, mixing powders and firing in continuous furnaces at a temperature of 750-850 ° C, characterized in that the obtained the high-siliceous fraction of the raw material is activated by heating at a temperature of 200-450 ° C, then soda ash is added in an amount of 12-16 wt.%, the resulting mixture is compacted in the form of heat-resistant steel, put the mold in a continuous furnace, heat treat with exposure at a maximum temperature of 10-20 minutes and the resulting cake is ground.