CS269680B1 - A blend for producing a periclasospinel refractory builder - Google Patents

Abstract

The solution relates to a forming mixture for the production of periclase-spinel refractory building material containing 6 to 24% by weight of aluminum spinel MgAl^O. and using sintered magnesia β containing 4 to 8% iron oxide) Building materials are used for lining furnaces in the production of cement and lime. The forming mixture consists of sintered magnesia, fused or sintered aluminum spinel and granular corundum. The formation of aluminum spinel by the reaction of corundum with a grain size of 0.1 to 1.2 mm with the periclase environment is evident from the increase in volume. This process is contradictory to the excessive shrinkage of the solutions circulating in the iron-! (if corundum is not present) By supplying corundum in a specified grain size and in limited quantity, it will be possible to use } ferric magnesia for the production of periclaeospinel sulfur-resistant building materials

Description

EN 269 68ο B1 1

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composition for the manufacture of a heat-resistant pearlospinel-containing heat-treated composition comprising from 10 to 35 wt. aluminum spinel MgAl 2 O 4 - with respect to the use of aline magnesia and the addition of 4 to 8% iron oxide attracted from natural breuneritic magnesite. Construction material and uses hemp for alinace furnace lining in cement production and lime. In the prior art and in the manufacture of periclase-spinel constituents, the mixture is made of alumina and fused or sintered aluminum apinel. The extracts made from a mixture of said base materials in a ratio ensuring the desired composition in said solution and fired in tunnel, vesicle or other containers at a temperature of 1600-160 ° C. Aluminum spinel is obtained either by melting the magnesium oxide / alumina mixture, or by sintering the particles at a molar ratio of aluminum oxide of 1 to 1.5. At a molar ratio of more than 1, the product of the olination in addition to the aluminum cell also contains periclase and is referred to as periclaspinel double strand (hereinafter ADS).

If sintered magnesia made from breuneritic natural homognesite is used for the production of the building materials, it contains 4 to 8 wt. iron oxide, there is a significant shrinkage to dofermation during the firing of the compacts and an excessive dispersion of the product dimensions. One reason is the very nature of magnesia made from breuneritic magnesite, where the presence of iron oxides in a given set of multiple components induces the continued growth of peri-cob crystals during firing of moldings. It is associated with their shrinkage to a considerable extent and to the use of low-iron magnesia. The cause, which increases the effect, is the pressure at which the moldings loaded in the baking furnace are exposed to each other in the trays. The insignificant cause is the occurrence of the flowing phase, the essence of which is the brownmilerite mineral and the dicalciumsilicates. In the current system, into which the mixture, respectively. the periclasospinel builder is formed, the resulting mass at 1300 ° C, and its increasing temperature increases. Of these, the production of periclasospinel builders and the use of ferric magnesia is not well developed. Usually, the process is carried out in such a way that the compacts are fired in a temperature mode in order to keep the shrinkage and thus the variations of the product dimensions in the prescribed positions. The disadvantage is then the unfavorable thermotechnical parameters of the products, the considerable flow, the low volume stability at high temperatures and the low high-temperature strength.

The above described drawbacks are eliminated by the present invention, which is based on the production of a blend of pearl-spininel refractory builders comprising aluminum and saline magnesium spinel, characterized in that it comprises 6 to 24 wt. a molten spinel of aluminum or perllasospinel bilayer containing 50 to 72 wt. % alumina, from 90 to 70 wt. other magnesium containing 4 to 8 wt. % iron (III) oxide, 86% by wt. magnesium oxide and from 4 to 6% by weight of fused or sintered corundum in a grain size of 0.1 mm and below 1.2 mm. In the molding process, the mixture is moistened, provided with a conventional bond, and compressed to a pressure of 90 to 150 MPa for moldings which are fired at 1600 to 1700 ° C.

The sweep is based on the finding that the reaction between corundum and magnesium oxide at temperatures of 1600 to 1700 ° C produces spinel while increasing volume as a result of densities. According to the washing operations, the volume of the above reaction will be changed in real moldings if the corundum particles were greater than 0.1 mm. If they are smaller, the bippinel is formed on the matrix porosity task. Also, the formation of voids in each initially corundum bead contributes to the increase in volume, if it was greater than 0.1 mm and less than 1.2 mm. This is attributed to the unequal upstream diffusion rate of aluminum and magnesium ions during the reaction. The volume increase increases with increasing corundum particle size as well as with its content. By using particles larger than 1.2 mm, the lining of the building material is disrupted by increasing the crown content above 6% to excessively increase the porosity. The above-described action provides for sintering of the periclase substance with the anticreep of the molded parts, and it can be used to control the total change in the volume of the moldings by firing using ferric magnesia.

Periclasospinel conglomerates for lining kilns in the production of cement and lime are produced in. 2 CS 269 680 B1 with several species, and with a spinel content of 10 to 35% by weight. The maximum content of corundum in the forming composition is 6%. 8.4 wt. spinel in the product. Therefore, the pre-synthesized fused spinel or periclasospinel double strand is included. It is also an advantage of the present invention to be able to replace the sintered magnesium part with a content of 4 to 8% by weight. of magnesium oxide containing 96 to 99.5 wt. of magnesium oxide and 0.1 to 2 wt. iron oxide. This replacement is important in the preparation of the molds that will be used for building materials used in the production of white cement. Execution Examples »'

Model builders made of basic materials with properties! according to Tab. I. Preparation mixtures were prepared in the kits according to Tab. II. The binder used was a saturated magnesium sulfate solution and a solid sulfite leachate. The moisture of the blends was 1.9% by weight. The compression was 100 MPa for 250x125x65 mm. The compacts were fired at 600 ° C for 5 hours at the indicated temperature. The properties of model builders and firing is summarized in Tab. II. The builders according to the invention correspond to the models designated D and E, the others have looked at the effect of the invention.

Properties of used basic materials

Tab. I Periclase-Aluminous Ferric Magnesium Magnesium HJH Double Leaf "LiADS" Silica / SiOg / / / 0,16 0,60 0,90 Aluminum Oxide / Al20 ^ / /% / / 0,04 '0,24 58,00 Ferric Oxide / PegOy /% / 0,46 8,00 3,58 Calcium Oxide / CaO / / / 0,40 2,30 0,96 Magnesium Oxide / MgO / / ^ / 98,48 88,62 35,70 Bulk Density ? /g.cm"^3 3.33 3.34 3.25

Tab. II

Composition of the blend, shrinkage, product properties. AB ”CDE Mass / Magnesia T Compound 1-3 mm 30 32 40 35 35 Magnesium" J "0.5-1 mm 10 10 15 10 1C Magnesium" J "-0.1 mm - - 35 35 - Magnesia "li" -0.1 mm 35 35 - - 35 Spinel -MABS 25 20 10 20 16 Corundum fused 0.5-0.63 mm - - - 4 4 Tabular alumina -0.1 mm 3 - - - Products construction Bulk Density * / g.cm - ^ / 3,04 3,06 3,07 2,93 2,90 Apparent Density / £ / 15,2 14,4 14,1 17,9 18,6 Cold Compressive Strength / MPa / 45 77 62 39 38 Bending strength at 1500 ° C / MPa / 1,1 1,7 0,4 1,1 1,3 Shrinkage molding at 1600 ° Cz% vol / 5,8 5,8 6'5 2.3 1.2

Claims (3)

EN 269 680 B1 3 OBJECT OF THE INVENTION 1. A blend for producing periclase-spinel refractory aluminosilicate (MgAl2O3) and sintered magnesium, characterized in that it comprises 5 to 24 wt. fused aluminum spinel or periclasospinel bicarbonate containing 50-72 $ alumina and 90-70% w / w alumina; % sintered magnesia containing 4 to 80 wt% ferric oxide, 86 to 91 wt. of magnesium oxide and from 4 to 6 wt. fused or corundum alumina in grain size above 0,1 mm and below 1,2 mm. 2. A blend for producing a periclasospinel refractory building material according to claim 1, wherein 30 to 44 wt. sintered magnesia containing 4 to 8 wt. of ferric oxide is replaced by sintered magnesia containing 0.1 to 2 wt. % iron oxide and 96 to 99.5 wt. of magnesium oxide. 3. A blend for producing a periclase-resin refractory composition according to claim 1, wherein the fused or sintered corundum is in the grain size class above 0.2 mm and 0.7 mm. >