CS241386B1 - Mixture for acid plastic refractory materials' surface treatment - Google Patents

Abstract

The purpose of the solution is to ensure the use of acidic refractory materials with chemical bonding even in alkaline formulations. Listed purpose is achieved by making the surface functional the product blank or the product provided with a mixture containing 1 to 90 wt. percent fillers, preferably coupé drift and from 10 to 99 wt. percent plasticizing 3 to 15 wt. percent % of water glass, 20 to 40 wt. percent water and 45 to 70 wt. percent kaollin. The composition may contain 0.5 to 70 wt. percent inert carbon-based constituents.

Description

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The purpose of the solution is to ensure the use of acid-resistant refractory materials with chemical bonding even in basic agents. This is accomplished by providing the surface of the functional blank of the article, or by providing the composition with a mixture of 1 to 90 wt. percent filler, preferably bulk drift, and from 10 to 99 wt. percent plasticizer component of a suspension of 3 to 15 wt. percent water glass, 20 to 40 wt. percent water and 45 to 70 wt. percent kaolin.

The composition may contain 0.5 to 70 wt. percent of the carbon-based inert component.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composition for surface treatment of acidic refractory plastics with chemical bonding for use in basic environments.

At present, acid refractory materials, in particular with a chemical acid bond, are used only in acidic or neutral environments. They are unsuitable for alkaline environments due to interactions that accelerate corrosion, especially when temperature fluctuations occur. This prevents the use of other, positive properties of these materials, in particular their low temperature dilatation changes. In direct contact of acid-resistant refractory materials with alkaline blast furnace slag, foundry operations, lining furnaces for the combustion of high-alkali fuels, for example in wood waste incineration, as well as in burners where dusts with a higher percentage of alkali or alkaline earths are entrained, they are formed on the contact surfaces at high melt temperatures, which react with the acidic components of the refractory. First it dissolves the phosphate component, then the aluminum amphoteric component. These melts penetrate relatively quickly through the shard mass of the refractory material and exhibit significantly different thermal dilatation changes from the original material, so that stress fluctuations occur between them, the values of which usually exceed the strength of the original lining, and thereby develop cracks that help further melt penetration resulting in accelerating corrosion. Therefore, materials which react with the melt considerably slower, but have inferior mechanical properties and are much less well tolerated by rapid temperature changes, are used for the environment, so that their service life is low in the environment. In addition, tars are used as a binder for these compositions, such as anhydrous chute compositions, which distil them at high temperatures and contaminate the working environment with carcinogenic substances and combustion products of incomplete combustion, in particular carbon monoxide.

The aforementioned drawbacks are eliminated by the surface treatment composition of acidic refractory plastics according to the invention, which consists of containing from 1 wt. percent to 90 wt. % filler, preferably flake dust, and from 10 wt. percent to 99 wt. percent plasticizer component. The plasticizing component consists of a suspension of 3 to 15 wt. percent water glass, 20 to 40 wt. percent water and 45 to 70 wt. percent kaolin. The surface treatment composition of acidic refractory plastics may contain from 0.5 to 70 wt. percent of an inert component consisting of carbon or its compounds, for example graphite or carbides, in particular silicon carbide.

This mixture is alkaline and therefore adheres perfectly to the surface of the acidic refractory at higher temperatures and does not react with the alkaline melts. Its temperature dilatation changes are identical to the temperature changes of acidic refractory material and therefore there is no breaking of the connection between them during severe temperature fluctuations. On the contrary, these fluctuations release the melt from the lining, which facilitates their removal. The alkali content of this protective layer must be such that there is no deeper penetration of the alkali into the acid mass, and vice versa that the alkali content of this mass safely prevents the penetration of other alkali from the melt.

The base of the mixture is kaolinite or alkaline silicate kaolinitic clay which forms a plasticizer component with water and a protective layer base. The effect of this layer is enhanced by the addition of an inert carbon-based component or its compounds. On the one hand, the inert component is neither wetted nor reacted with the melt, but its surface decomposes slightly with the evolution of gases, thereby forming an insulating microlayer and preventing the melt from adhering to the refractory lining.

An illustrative composition of the surface treatment composition of acidic refractory plastics is given in the Examples.

To protect the embossed burnt pieces of acid-resistant refractory in the lining of a wood-burning furnace, a trowel finish is used:

wt. percent kaolin, wt. percent flak drift, wt. percent of a 30% potassium waterglass solution having a molar modulus of 2.5 wt. % by weight of silicon carbide having a grain size of from 0.01 mm to 5 mm; percent water.

The layer of the mixture is applied with a thickness of min. 1 and max. 3 mm.

In the second example, a mixture layer consisting of the following is applied to a blast furnace trough lined with burnt-out acid refractory shaped pieces.

wt. percent of ground graphite, wt. percent kaolinitic clay, wt. percent by weight of a water glass solution having a molar modulus of 4 and a wt. percent flak drift.

Water is added to the mixture until a consistency suitable for coating is achieved.

Claims (2)

SUBJECT CLAIMS 1. A composition for treating a surface of acidic refractory plastics, characterized in that it comprises from 1 wt. percent to 90 wt. and from 10 wt. percent to 99 wt. % of a plasticizing component consisting of a suspension of 3 to 15 wt. percent water glass, 20 to 40 wt. percent water and 45 to 70 wt. percent kaolin. VYNALEZU 2. A composition for treating a surface of acidic refractory plastics according to claim 1, comprising 0.5 to 70 wt. percent of an inert component consisting of carbon or its compounds, for example graphite or carbides, in particular silicon carbide.