CS267149B1 - Refractory laminated ceramic shaped bricks - Google Patents

Abstract

refractory layered fittings o the same thermal expansion of the layers formed by internal working and external thermal insulation layer that are integrally combined. The inner layer contains 70-30% vol claystone up to 3 mm, with a proportion of 10% below 0.09 mm and 30 to 70 »refractory clay grit with a residue of 10% on nets 0.1 mm. Outer thermal insulation layer contains 20 to 30% by volume of lupine, 20 up to 40% refractory clay and 30-60% expanded perlite with grains up to 1 mm. If desired, the inner layer may be with a layer of abrasion resistant refractory ceramic material. Product falls into the refractory ceramic industry material and is intended for use up to 1400 ° C.

Description

The invention relates to refractory layered ceramic fittings with two to three layers, the inner of which is working, optionally provided with another layer of abrasion-resistant ceramic material, and the outer of which is thermally insulating. All layers are firmly and permanently connected to each other into a single integral whole. The connection takes place by compression with subsequent firing, during which the physicochemical transformations of the mixtures take place, which further intensify the connection. The mutual connection is aided by the presence of expanded perlite in the mixture of the thermal insulation layer, which acts with its sintering effect at the points of contact of the layers ·

The fittings are designed for linings of thermal equipment operating at temperatures up to 1400 ° C, where their thermal insulation properties are economically applied. In this case, the layers are joined with mortar or glued. However, this method has the disadvantage that the materials of the layers thus composed generally do not have the same thermal expansion. This causes tension in them during operation. This tension usually results in the mortar being chipped and the mutual incoherence of the expansion joints causes the integrity of the lining to be damaged. Sometimes the layer materials react chemically together, which is always unfavorable.

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Another method of layering materials with different properties is known from the use of granular refractory materials for monolithic masonry. Even here, however, the problems of different thermal expansion and thus the problems of permanent mutual cohesion of the layers remained unresolved. · The first heating of the lining of unfired, unshaped materials is also a problem. Attempts have been made to solve problems with different extensibility by inserting compensators between layers. This is the case with DEi.310 5595 using ceramic fibers in conjunction with clay and chemical bonding. However, problems with fiber corrosion have emerged. Attempts to solve problems by incorporating fibers directly into the molding composition are also known. However, it has been shown that ceramic fibers undergo structural changes at high temperatures, under the influence of the kiln atmosphere, which disrupt the lining. The attempts of the American authors of EU-patent no. 0086501 based on the use of suspensions to form layers. Technical solutions based on the use of layered fittings are also known. Combinal fittings are produced on their basis in the GDR. The same is true of the Japanese invention No. 57-170881, where layers with different bulk densities were also used. These products have not been used due to the persisting problems of varying extensibility and also because they are materials of high temperature classes and therefore expensive. In the USSR was awarded the author's certificate no. AO 637 391, solving the production of layered fittings by casting from ceramic suspensions. A method according to the patent DE £ 110 8130 is also known, which solves the production of layered fittings by pressing a fired fitting into a granular unfired ceramic mass. Other solutions, for example according to DE-234 6113 and Japs. 57-205384, are based on the use of a fiber core in a thermal insulation material which is pressed or embedded in a ceramic suspension to form a working layer.

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A wider application of such composite materials preventing complicated and expensive technology · Při_tom market lacked ^ ruh stratified material manufacturing nenákl whatsoever, _and in wide use up to temperatures of 1400 ° C. It is also the case that the fittings guarantee a firm and permanent connection of ordinary SI fireclay in combination with cheap lightweight fireclay. · Such a product is the subject of the invention. The way of its technical solution eliminates the problems of integral connection without the risk of breaking the lining. During the development of this layered material, the assumption that the expanded perlite used in the thermal insulation layer composition contributes at the interfaces between the dense and expanded material to the firm bonding of the layers by diffusion interweaving and its sintering effect was confirmed.

The invention relates to refractory ceramic laminate fittings consisting of an inner working layer and an outer heat-insulating layer. up to 30% by volume of shale or claystone in a grain size of up to 3 mm, with a proportion of 10% below 0.09 mm, 30 to 70% of refractory clay in a grain size of 10% on 0.1 mm nets, both components containing at least 39 wt. % alumina and their heat resistance is 1,730 ° C.

The outer layer contains up to 30% by volume of shale, 20 to 40% of refractory clay, 30 to 60% of expanded perlite with a grain size of up to 1 mm.

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The layered refractory ceramic materials according to the invention have a number of advantages in comparison with the types of fittings glued into layers with mortar or glue. using these fittings are lower than the costs associated with β by lining the individual layers · The number of joints is reduced »lining repairs are easier and the linings have a longer service life because they do not break down due to non-uniform chisels * Assembly of the lining is also facilitated ·

The invention is illustrated by 4 examples of possible embodiments and also indicate the possibility of choosing an economically optimal composition of fittings · Examples differ in the degree of lightening of the fitting table for examples ·

Example 1

A mixture intended for the inner layer A was prepared. W-special clay with a residue of 10% on 9.1 mm nets · Furthermore, a mixture was prepared for the outer layer B, composed by volume of 20% fired flake B / 2 up to 3 mm, then 20% refractory W-special clay and 60% expanded perlite with grain size up to 1 wound ·

A sheet metal, organ-shaped insert with 40 mnu teeth was inserted into the mold for C-32 bricks, with an internal diameter of 320 x 158 x 78 mm, 78 mm in height. of the free spaces, mixtures A, B were poured separately and after removing the insert, the whole was hydraulically compressed with a pressure of 30 MPa.

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The detected thermal insulation effect was 23%.

Example 2

Mixture A was prepared for the inner layer composed of by volume not% of burnt shale of the same kind as in Example 1, 40% of refractory grain clay as in Example 1 ·

For thermal insulation layer B, a mixture of volumetric flake%, burnt clay,% refractory clay,% expanded perlite, all in grades and grain sizes as in Example 1 was prepared. the inner space was divided by volume so that a space of 38% was created for the inner layer and 62% for the outer layer. After filling the mold and removing the insert, the following procedure was followed as in Example 1 · A thermal insulation effect of 13% was found on the fired fitting ·

Example 3

A ceramic mixture was prepared for the inner layer A with a volume composition of:

% burnt shale, 35% refractory clay ·

For the outer layer, mixture B was prepared with the composition of% burnt flake,% refractory clay,% expanded perlite, all in grades and grain sizes as in Example 1. · allowed volume volume A / B 1.5: $ 2.5 ie · 0.015 v? for indoor and 0.025 in? for the outer layer · Other procedure according to Example 1 · The thermal insulation effect was 18.6% ·

-cExample 4

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For the fitting with an abrasion-resistant layer on the inner side, the so-called large standard C 30 grinders 300 x 148 x 65 mm with a volume of 0.289 m was approved. The inner space of the mold was divided by two organ-shaped sheet metal inserts with partial volumes:

0.130 iP for inner layer A, • a *

0.130 nr for layer B "o"

0.029 nr for abrasion-resistant layer C. For layers A and B, the mixtures according to Example 1 b were used, with the difference that claystone of the same characteristics was used instead of fired shale. For the abrasion-resistant layer C, a mixture corresponding to the composition of STI hard fireclay was prepared, consisting of 70% by volume of slag and 30% W-special clay.

Table

Properties of physico-mechanical fittings according to the invention Example 1 Example 2 Example 3 Example 4

4.91 1 420 1 320 tn co 1 620 2 060 ocn \ OCM COt- * WHAT o o o o o * rcM CM Or- * •• H r- O> Fh AND σ \ r * O o 7.01 O 1 310 with 1 600 2 040 t-co iacm CO CM e » <n o oooo r- Μ · <Ό «* r- O AND 18.6 & a <0 o v— IN" 1 310 and 1 620 2 030 ιτ \ σ \ incu CO CM WHAT O o 00 o T- O CO M-COCM O «H> h AND Fitting weight, kg 7.09 Resistance to deformation in heat under load o OJ ϋ o aJ Š CM o • rl A CQ> layer B at 0.1 MPa 1,300 Apparent comparability% layer B 35 Bulk density kg m -1 layer B 1,600 layer A 2,050 Compressive strength MPa layer A 60 layer B 27 Length changes by burning% layer A 3 layer B 3.2 Specific thermal conductivity - layer A / 1400 ° C wm K 1,418 layer B 0,593 _Λ at 1200 ° 0. — ........- .. ... .......... - - - ______________________ Thermal insulation effect fittings% 23

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Claims (2)

Refractory first layered ceramic shaped six _t dripping from the inner and outer layers * are a mixture of sand and binding, wherein said inner layer comprises by volume 70 to 30% of lupins or claystones with a grain size of up to 3 mm, with a proportion of 10% of particles below 0.09 mm » 30 to 70% refractory clay in a grain size with the remainder 10% on 0.1 mm sieves, and the outer layer contains 20 to 30% dandruff, 20 to 40% of refractory clay and 30 to 60% of expanded beads with a grain size of up to 1 mm. 2. Refractory laminated ceramic fittings according to claim 1, characterized in that the inner layer is provided with a layer of abrasion-resistant refractory ceramic material, such as fireclay.