RU1787965C - Process for producing porous vitrified block - Google Patents

Abstract

SUMMARY OF THE INVENTION: In the method for producing a porous vitrified block by continuously loading a charge, simultaneously foaming it and forming a block, quartz-containing loams are used as a charge, and they are fed into a zone with a temperature of 1060-1300 ° C at a speed that ensures speed. heating 180-400 ° C / min. Block characteristic: density 400-900 kg / m3, strength 8.4-15.3 MPa. 1 tab.

Description

The invention relates to the production of building materials and can be used in the production of heat-insulating, large-block wall and decoration elements and parts, fillers of lightweight concrete.

Known methods for producing foam glass by preparing the mixture, glass melting, molding and annealing, when reducing agents are introduced into the mixture, the molten glass is boiled in a controlled atmosphere at 1350-1510 ° C (1-2 hours) and additional heat treatment is performed in the temperature range before annealing softening 700-800 ° C, or another technological step is used - granulation of the finished glass melt and its subsequent grinding together with a blowing agent before secondary heat treatment,

These methods require significant energy costs for mixing the starting components and preparing the charge, its heat treatment and additional technological operations, including the formation of blocks, their compaction, etc.

The closest in technical essence and the achieved result is a method for producing foam glass by foaming a mixture represented by natural types of raw materials (clay, rocks such as quartz sand), as well as industrial waste (pyrite cinder) and gasifier - coke residues from TPP ashes. The essence of the technical solution lies in. the fact that the mixture is dried, crushed, filled up in refractory forms and foamed at 1180-1200 ° C. The duration of heating, sintering and foaming is 1 hour, and annealing is 9 hours. The disadvantage of the prototype is the great complexity and energy consumption of the process, due to the need for the preparation of a multicomponent charge, including drying, grinding, weighing, mixing, as well as prolonged heat treatment of a previously formed charge .

The aim of the invention is to simplify the technology for producing porous vitrified material.

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The goal is achieved in that in a method for producing a porous vitrified material from a mineral glass-forming raw material. As the latter, widespread sedimentary rocks such as quartz-containing loams without any undercuts and without pretreatment (mechanical or thermal) are used. Loams have gaseous losses when calcining from 3 to 9 mass percent, which are due to the presence of carbamate and chemically bound water. The process of foaming the material a and forming products from it is carried out simultaneously and continuously, adding the initial charge to the foaming zone in such a way as to ensure its heating at a speed of 180-400 degrees per minute to the sintering temperature, but not higher than the temperature of the charge.

The use of sedimentary rocks such as loams as the initial non-deficient raw material; in which, when heated at the indicated rate, the processes of degassing and the formation of glass phases coincide in time, and the formation of higher-temperature crystalline phases is insignificant, you can use the proposed method to reduce the cost of scarce components used as blowing agents, oxidizing agents and fluids; reduce the energy intensity of the technology and simplify it due to the lack of operations for the preparation of the mixture, compaction of the blocks, etc. In addition, due to the continuity of the process, effective conditions for self-annealing of the material are achieved, which also reduces energy consumption and simplifies the process. The result is a porous vitrified material that is reinforced with relict crystalline grains and is characterized by low bulk density, significant specific strength and ultra-high frost resistance.

In the absence in the initial charge (for example, in igneous rocks or granular glass) in a sufficient amount of components dissociating upon heating with gas and vapor formation (in the form of CO2, H2, Oa, etc.) for foaming, of course, a suitable addition of blowing agents is needed, as is the case in the prototype. Sedimentary rocks, including loam, as a rule, possess such components in the form of carbonates of alkaline-earth elements and chemically bound water, which made it possible to develop a method for foaming them without preliminary preparation.

The choice of a heating rate of 180-400 ° C / min is due to the fact that the above combination of dissociation processes with the release of gaseous and vaporous components and the formation of a glass phase are realized. When the heating rate is less than 180 ° C / min, dissociation processes practically end by the beginning of the intense formation of the glass phase (refractory temperature), which leads to an increase in bulk mass (decrease in porosity). At the same time, the process of glass phase formation is accompanied by its consumption for the formation of new crystalline phases having a high melting point, which leads to an increase in energy consumption and the fundamental impossibility of producing foamed material.

At a heating rate above 400 ° C / min, it is not possible to achieve uniformity of the porous structure in the real volume of the material, since an abundant, low-viscosity glass phase is formed, and a high dissociation rate leads to unlimited growth of pores and breakthrough of their walls. The same is observed when refractory temperatures are exceeded, resulting in a decrease in strength and other performance properties.

At an insufficient temperature of the heating zone (lower sintering temperature), the formation of the glass phase is insignificant and, due to intense vapor and gas evolution, a loose, scattering material is formed.

Comparative analysis with the prototype allows us to conclude that the claimed method differs from the known expressness based on the use of extreme thermal shock during foaming (180-400 ° C / min) instead of smooth heating and longer heat treatment of the prototype (1 h) . A one-component charge (loam) is proposed instead of a multi-component charge in the prototype,

The implementation of the proposed method is as follows.

A mold made of refractory material was placed in the heated space of a special. Raw materials (loams) were continuously fed into the mold at a speed that ensured a given rate of their heating. Lump sizes were selected based on preliminary experiments on discrete foaming. The feed rate of the mixture was selected so that the change in the set temperature did not exceed 2 degrees. Blocks of porous glassy material with dimensions of 80 x 100 x 140 mm were obtained. Loams of the Markovsky, Kedrovsky and Oktbrsky deposits of the Tomsk region were used. Technological parameters and properties of the materials obtained are given in the table. Situations when the heat treatment temperature was lower than the sintering temperature and higher than the refractory temperature did not lead to positive results at any heating rates and are not shown in the table. Examples with heating rates of 150 and 450 degrees per minute for all materials are prohibitive in the proposed method. The upper and lower limits of bulk density and compressive strength correspond to the extreme values for a series of measurements on four samples cut from each block obtained. The absence of some data in the table corresponds to cases of impossibility to obtain them due to self-destruction of the samples.

Bulk density was defined as the ratio of the mass of the sample to its geometric volume. The compressive strength was determined by crushing samples of a cubic shape by a known method. Correction of the data taking into account partial destruction of the samples during sawing was not carried out.

The proposed extreme method allows you to use any quartz-containing loam (non-deficient raw materials), simplify the technology and, accordingly, reduce the cost of obtaining porous vitrified material, which can be used as thermal insulation, wall and decoration elements in construction, as well as fillers lightweight concrete. The method also makes it possible, due to the continuity of the process, to realize the production of large-sized elements.

Claims (1)

SUMMARY OF THE INVENTION A method for producing a porous glazed block by continuously loading a charge, simultaneously foaming it and forming a block, characterized in that, in order to simplify the technology, quartz-containing loams are used as a charge, and they are fed in a zone with a temperature of 1060-1300 ° C at a speed that provides a heating rate of ISO-4000 / min. Loam Map- 1200 Kovskoe place- T556 birth 1060 Loam Ked- JJ60 Rovskogo place- TlOO birth 1100