SU1079638A1 - Refractory composition - Google Patents

Abstract

Refractory mass, including refractory filler and slag-made carbon-free ferrochrome, characterized in that, in order to increase heat resistance and reduce shrinkage, it contains fireclay containing AEg as fire resistant filler. 0% 33-8O wt.% In the following ratio, wt.%; Fireclay with the content of Al2O 33-80 wt.% 60-85 Slag production of carbon-free ferrochrome 15-4O (L

Description

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00 The invention relates to the refractory industry and can be used in the manufacture and repair of monolithic liquid and printed refractory linings of metal heat units; Chemical, mining, chemical, cement and other industries. A heat resistant concrete mixture is known, including alumina cement, chamotte, water, and kalshsh nitrate crystalline hydrate il. The disadvantage of this mixture is a slower rate of hardening, which significantly lengthens the duration of the manufacture and repair of linings. This is due to the absence or insufficient content of highly active calcium aluminates in the composition of the alumina cement used. The closest technical solution to the invention is a refractory mass for the production of refractory concrete, in which 8O-S5 wt.% Of metallic chromium slag with A content 81-86 wt.% Is used as the aggregate, and 15-20 wt. .% ground slag from carbon-free ferrochrome sfj production. This material has high refractoriness and deformation temperature under load, one low thermal resistance and insufficient volume, the mass of the mass excludes its use in thermal units with alternating hydrochloric operating temperature. The low thermal resistance of the mass is mainly due to the corundum composition of the aggregate, which has a relatively high thermal expansion coefficient of 8.0. Insufficient volume state is associated with shrinkage of the mixture due to phase transformations in the interaction of cement with aggregate during heating. The aim of the invention is to increase the heat resistance and reduce shrinkage. The goal is achieved by the fact that the refractory masses, including the refractory filler and slag for the production of carbon-free ferrochrome, as a refractory filler soda | chamotte with a content of 33-80 wt.% with the following ratio of components, wt.%: Chamotte with a content of A1203 33-80 wt.% 60-85 Slag of carbon-free ferrochrome15-4O production Replacing corundum aggregate containing 81-86 wt.% Pi. , on fireclay, having a mullite-siliceous composition, almost 2 times reduces the coefficient of thermal expansion, which leads to an increase in the thermal stability of refractory concrete, obtained from the proposed mass by 10 times. The decrease in the coefficient of thermal expansion of the mass is due to the formation in the composition of the ceramic binder, which is formed when the mass is heated, the cordierite mineral, which is characterized by low thermal expansion (2, О1О degrees). The high-temperature synthesis of cordierite and partially other aluminosilicates as a result of the interaction of chamotte with finely ground slag of carbon-free ferrochrome is accompanied by a positive change in volume, which largely compensates for shrinkage and ensures the bulkiness of the material. The slag of carbon-free ferrochrome, which performs the functions of hydraulic propulsion, is 15-4 O wt.%. With a lower content of this component, the strength after hardening dramatically drains, and with its higher quantity, the thermal resistance and refractoriness of the mass decrease. The optimal concentration of chamotte aggregate was 3380% by weight. When the content of this ingredient is less than 33 wt.%, The thermal stability of the mass is reduced. The increase in the content in the aggregate more than 80 wt.% Also impractical because it leads to an increase in porosity and reduced mechanical strength of refractory concrete when heated. PRI me R. As raw materials, waste slag from the production of carbon-free ferrochrome by the aluminothermic method and chamotte aggregate of a fraction less than 5 mm according to TU 14-8-145-75 (grade ЗМКР) are used. The chemical composition of the slag is as follows, wt%: CaO 18.9-, 5; 5i02 2.3; re 20 1.6; A120 the rest. For the preparation, the slag is subjected to TOHKj iy grinding to a specific surface area of 0.4. Samples of chamotte and slag are prepared using conventional ceramic technology and subjected to exposure; They are fired at 14AS. The material composition of samples from the known and proposed refractory masses of lead; den in table. 1. In table. 2 presents the properties of the proposed and known refractory masses.

As can be seen from the table. 2 data, the indices of thermal stability and & of the impedance of the proposed refractory mass substantially exceed the values of the analogous properties of the prototype.

The proposed refractory mass allows efficient disposal of waste slag from the production of carbon-free ferrochrome by aluminothermic-KIM method, makes it possible to entrust the economy of mecKfdi economy from using one ton of material in the amount of 45-5O rubles; and also allows to increase the resistance of the lining of the pumping aggregates by 1.3 times in comparison with the applied refractory mass based on fireclay and ordinary aluminous cement.

I.T a b L and rS 1

Fireclay fraction less than 5 mm. with content

Compositions outside the proposed limits.

Table 2

Claims (1)

REFRACTORY MASS, including refractory filler and slag, production of carbon-free ferrochrome, characterized in that, in order to increase heat resistance and reduce shrinkage, it contains chamotte containing AE2 as a fire of persistent filler. 0¾ 33-80 wt.% In the following ratio of components, wt.%? Chamotte with content A1z0 ^ 33-80 wt.% 60-85 Carbon-Free Ferrochrome Slag ’15-40 In (L with about m