RU1787980C - Method of producing refractory heat insulating material - Google Patents

Abstract

Usage: refractory coating technology for protecting engineering products from high temperatures. SUMMARY OF THE INVENTION: A pre-dispersed mineral aggregate is mixed with a binder-colloidal alumina solution, the liquid phase is separated, dried and calcined at a temperature of 600-900 ° C. The resulting products are characterized by heat resistance of 1500-1600 ° C and a compressive strength (at 10% strain) of 20-30 kg / cm2. 2 tab.

Description

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The invention relates to the field of chemical technology, namely to the production of heat-protective coatings having high thermal stability and low bulk density. The developed method for manufacturing a refractory heat-shielding material can be used in various fields of engineering to protect critical products from high temperatures.

A method for producing aluminum oxide ceramics is known, comprising mixing a mineral aggregate (deep calcined low alkaline alumina) with an aqueous solution of aluminum oxynitrate and magnesium salt, separating the liquid phase and heat treating.

The disadvantage of this method is the high heat treatment temperature.

The closest in technical essence and the achieved result is a method for producing a heat insulating material consisting of aluminosilicate fiber and silica sol.

In this method, aluminosilicate fiber in an amount of 95.5-98% is mixed - with a silica sol in an amount of 2-4.5% based on dry SI02, the liquid phase is separated and the resulting material is calcined.

The disadvantage of this method is that the materials obtained by it have insufficiently high thermal stability associated with the melting of silicon oxide and aluminum silicates at a temperature of 1400-1600 ° C.

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The aim of the invention is to increase the heat resistance and strength of the resulting heat-shielding materials.

This goal is achieved by the fact that in the known method of manufacturing a refractory heat-shielding material, comprising mixing a mineral fiber and a binder, separating the liquid phase. And heat treating as a binder a colloidal solution of alumina (al; omosol) with the following characteristics: A1 / ratio MO 3 (4-8) / 1, concentration 3-10%.

The method is carried out as follows:; . . . :. V.

At the first stage, dispersion of coal wool in hot water is carried out at a temperature of 60-80 ° C. Dispersion is carried out in a jacketed reactor using high-speed screw or paddle mixers. Dispersion is carried out for 10-30 minutes. After that, the suspension obtained is sedimented, and agglomerates and large fibers are deposited on the bottom of the reactor. Subsequently, the fibers are mixed with a colloidal solution of alumina, the liquid phase is separated, dried and calcined at a temperature of 600-800 ° C. ,: .-, f,:. -,:. ,,,, -.-:

Example 1. In 1 liter of distilled water at a temperature of 90 ° C disperse 50 g of cotton wool. Dispersion is carried out for 30 minutes. The resulting suspension is left to stand for T min and the agglomerates and coarse fibers that settle to the bottom are removed, and the liquid phase is removed. The resulting fiber was mixed with 1 L alumrzole with a ratio of A1 / LOZ 8/1 and a concentration of 6%. Then, the liquid phase was separated, dried and calcined at a temperature of 800 ° C.

Analogously to Example 1, we carry out a test for aluminosols with other characteristics. The results are shown in table 1.

Based on the results of the experiments shown in Table 1. It can be concluded that it is preferable to use alumozole with the following characteristics: A1 / LO3 ratio 8/1, concentration 6%.

As can be seen from table 1, the concentration of alumozole below 3% leads to a significant

reduction in compressive strength, and the use of ashes with a concentration above 10% leads to an increase in the density of samples, which affects the thermal properties of the material.

When using the AI / NOa ratio of less than 4/1 and above 10/1, a significant decrease in the compression limit is observed. ; :. -::

Obtaining alumozole with a concentration

above 10% is associated with a significant complication of the process. For the same reason, as well as due to the excessive stability of the resulting sols, the AI / NOa ratio should not be increased above

8 / 1.- -, ...:. V, -. :;. / .. Example 2. Comparative tests of the properties of the described materials made according to the prototype method are carried out. The comparison results are presented in

Table 2U -:; v: - 1-.:/ i:.; ;. ;: ..:

As can be seen from table 2, the resulting material has great strength and heat resistance.

Thus, the proposed method

The production of refractory heat-shielding material provides, in comparison with the prototype, an improvement in the operational properties of the material due to an increase in strength by 30-50% and heat resistance at 200,000 ° C.

Claims (1)

SUMMARY OF THE INVENTION A method for producing a refractory insulating material, comprising mixing a mineral filler and a binder, separating the liquid phase and heat treating, characterized in that, for the purpose of increasing heat resistance and strength, a colloidal solution of alumina is used as a binder with a concentration of 3-10% and a ratio of A1 / MOH equal to (4-8): 1. Table 1 table 2