SU1738791A1 - Stock for producing refractories - Google Patents

Abstract

FIELD OF THE INVENTION The invention relates to a refractory industry, namely to compositions of high alumina refractories. The mixture contains, wt%: aluminum-chromophosphate binder (AHFS) 6-9. alumina 32-36. quartzite containing component 14-22, dispersed aluminum-chromium catalyst waste of petrochemical production 5-10 and the corundum-containing component the rest. The mixture is prepared as follows. Initially, coarse corundum and aluminum-chromium wastes are mixed with moisture to 3.5%, then crystalline silica and alumina are loaded and mixed for 2-3 minutes. Then, AHFS is supplied and additional mixing is carried out for 2-3 minutes. The mass is pressed at a pressure of 80-100 N / mm2, then, after two hours of drying at the workshop temperature, the product is sent to the firing vessel at a temperature of 1600-1700 ° C. The compressive strength of the newly formed raw material is 3.5–5 N / mm, after drying it is 75–85 N / mm2. Heat resistance of 24-29 water heat changes. Deformation temperatures under a load of 0.2 N / mmg 1700-1725 ° C. Product wear after service in an induction channel furnace from 73-100 to 80-108 mm. 1 tab.

Description

The invention relates to the refractory industry, in particular to compositions of high-alumina refractories intended to serve under conditions of variable temperatures or intense exposure to slags, for example, in the arches of electric furnaces, as well as in immersed tuyeres when blowing metal through gases and powders.

The known charge for the manufacture of refractories of the composition, wt.%: Alumina hydrate 5-10, orthophosphoric acid 3-5, an aluminum-chromophosphate bond 3-15 and electrocorundum the rest. Products based on the known charge have insufficient

strength and heat resistance, which limits their field of application.

Closest to the invention is the mixture for the manufacture of refractories composition, wt.%: Electrocorundum 22-33.2, alumina 38-51. crystalline quartzite 18.5-28, orthophosphoric acid 4.8-7.5.

The disadvantages of the known charge are the relatively low strength of both the compressed raw and after drying, which leads to an increase in the rejects during the pressing of products and complicates the process of automating the removal of products; relatively low temperature resistance and wear resistance of products during operation in the arches

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electric furnaces, out-of-furnace steel processing units, etc.

The purpose of the invention is to increase the compressive strength of the compressed raw material and the product after drying, as well as improving the heat resistance and wear resistance of products in steelmaking units.

The goal is achieved by the fact that the mixture for the manufacture of refractory materials, including phosphate binder, corundum-containing component, alumina and quartzite, contains, as a phosphate binder, an aluminum-chromophosphate binder and additionally dispersed aluminum-chromium wastes of a petrochemical catalyst in the following ratio of components, wt.%: Al hummochrome phosphate binder. 6-9

Alumina32-36

Quartzite-containing component14-22 Dispersed aluminum-chromium catalyst waste of petrochemical production 5-10 Corundum-containing component Rest Aluminum-chromium catalyst waste of petrochemical production (AXO) is a dispersion (less than 0.06 mm, the prevailing particle size of 70-20 microns) high clay material with a fire resistance of 1760 ° С following chemical composition. wt.%: 75 A1aOz; 11.6 SpgOz: 10.2 SiOr, 0.78 TiO2; 0.5 Rv20z; 0.3 CaO; 1.62 R20.

Alumochromophosphate binder (AHPS) is a solution of orthophosphoric acid with alumina hydrates and chromium oxides (TU 6-18-166-83) with a density of 1.60-1.74 g / cm3 and composition of AteOs 0.8 of Co2O3 PaOsThe mechanism of the hardening of the mixture of the specified composition due to the bonding of particles of refractory aggregates (crystalline silica and granular corundum) and the formation of hydrogen bonds of phosphate anions with their surface at relatively low temperatures. To a considerable degree, it is intensified by the presence of the Cr + 3 cation in the aluminophosphate solution, solid dispersed particles of chromium, aluminum, silicon oxides included in the AChO, and the finely dispersed state of the alumina component. Chromium cations, the bulk of alumina and fine particles of chromium oxides, silica and alumina accelerate the chemical interaction of coarse corundum and silica with a phosphate binder, the product of which is

the formation of acidic one- and two-substituted aluminum and silicon phosphates, as a result of which, during the formation period, the mechanical strength

raw material, which makes it possible to automate the removal of products and their load on the kiln car for firing, and also the ultimate strength of products after drying increases dramatically.

When heated, crystalline phases of mullite, cristobalite, trisubstituted aluminum phosphate are formed from these components, and a solid solution of corona in corundum is formed along the boundaries of corundum grains. The total specified

5 phases and their distribution in the refractory provide resistance to abrupt temperature changes. Cr20z solid solution in corundum and cristopalite form AIP04 with a relatively low coefficient of thermal linear expansion, hard

cementing refractory phases provide products with high thermal stability.

The deep dispersion and activity of cata chromium in the solution of an alumina chromophosphate binder, as well as the dispersion of solid particles CrO2 of catalyst waste, help solid-phase diffusion processes to form a chemically stable compound xCr20z. protect the refractory (the main components of its crystalline phases mullite, residual cristobalite, corundum, aluminum phosphate) from metal and slag in the

5 operating conditions, as a result of which the refractories significantly increase the service life in the linings of metallurgical and high-temperature units, especially in the after-furnace treatment of steel

0 blowing powders silicocalcium.

When the content of the AHPS contains more than 9% (composition 5 in the table), the compressive strength of the newly formed raw material decreases, the product geometry is disturbed

5 in subsequent manufacturing operations; the content of AHFS less than 6% reduces the density of raw and degrades the quality of products.

When the content in the composition of the charge AXO more than 15% decreases the density of products

0 after firing as a result of loosening effect: when the content of the AChO is less than 5%, the amount of the chemically inert compound A120z Cg20z decreases.

With contents of more than 37%

5 fine alumina, compaction deteriorates (there may be repressive cracks), with a content of 32% alumina, the yield of mullite decreases, the porosity increases, and the refractory wear increases.

When the content of the silica-containing component is more than 22%, as a result of firing, more residual cristobalite (less corrosion-resistant phase) is formed and the heat resistance is reduced; when the content of the silica-containing component is less than 14%, the yield of mullite decreases and the amount of glass phase increases, which reduces the wear resistance of the refractory.

The proposed composition of the components provides a significantly greater increase in compressive strength and heat resistance of products compared to the known. In addition, the proposed composition has a high wear resistance during operation in steel-making units.

PRI me R. The starting components were granular corundum (electrocorundum or sintered corundum shamot), dispersed alumina of the GK brand, granular crystalline silica component (quartzite or chalcedony), aluminum chromophosphate binder according to TU 6-18-166-83, and chromcedon alumina chromidone, aluminum chromic acid, and aluminum chromic phosphate binder according to TU 6-18-166-83 and aluminum chrome waste catalyst. (AHO) TU 38-30-32-83.

Coarse-grained corundum and AXO are pre-mixed with moistening up to 3.5%, then quartzite and alumina are introduced and mixed for 2-3 minutes. Then served AHFS and again stirred for 2-3 minutes. The mass is pressed at a pressure of 80-100 N / mm2. then after two hours of drying at the workshop temperature, the products are sent directly to the load at

Pok.atheymm snaygte refractory it

Kiln car for burning at 1600-1700 ° С. Indicators of the density and strength of molded products, the properties of baked products and the results of their service in metallurgical aggregates are given in the table.

Claims (1)

Claims of the invention for the manufacture of refractories, including phosphate binder, corundum-containing component, alumina and quartzite, containing a component characterized in that, in order to increase the compressive strength of the compressed raw and the product after drying, as well as to increase the heat resistance and durability of the refractory when working in steelmaking aggregates, it contains, as a phosphate binder, an aluminum-chromophosphate binder and additionally dispersed aluminum-chromium wastes of a petrochemical catalyst Production in the following ratio, wt.%: Alumochromophosphate binder alumina Quartzite-containing component Dispersed aluminum-chromium wastes of a catalyst for petrochemical production Corundum-containing component 6-9 32-36 14-22 5-10 Rest Alumina 32 Quartzite 14 AHO 5 AHFS 6 Elgktrokund Alumina 36 Quartzite 22 AHO 10 AHFS 3 Electrocoruid 23 Gliesei Z1 Quartzite 18 AHO 7.5 7.5 Electrocorundum 33 Alumina 3I Quarite 13 AXO 4 AXOS 5 Electrocorundum 7 Alumina 37 Quartzite 23 AHO II AHOS 10 Electrocorundum 1E Alumina S1 Chalcedony 18 AHO 7.5 AHFS 7.5 Electrocorundum 33 |, 0 79.0 220 171026 1192, 80-100 15, 5.075.0 ha 172529 3,585,02JO 17ЭО24 892,880-10012, 1171.0880-1051 3,585,0225 17P525,01002,380-105I 3.7К215 17Ю25 982,080-10013 , 578225 17SU2795.0 2.078-10015 171026 1192, 80-100 15.0 892,880-10012,0 1171.0880-1051 982,080-10013 3.7 3.5 -five - "ABOUT five .7-1, in "-5 230Я 700 Z14-J35 17 "0 3 Table continuation .0 1081.5 "O-10813 $ 1002,380-10 $ It 15-17 8-7 3.3-, 7 115-130b-I 5-15