The mixture for the manufacture of refractories with an irregular grain structure
(57) Abstract:The inventive mixture contains, wt%: granular refractory filler fractions of more than 0.5 mm in the number of 40 - 60% and the rest is finely dispersed mixture of a joint grinding particles less than 0.09 mm, and finely dispersed mixture comprises, by wt.%: corundum 40 - 63,5; alumina 0.5 to 25; kaolin 20 - 30; zirconium dioxide - the rest, but not less than 5. From the prepared mass is pressed blanks and burn them at 1520 - 1600oC. 1 table. The invention relates to the technology of refractories that can be used in ferrous and nonferrous metallurgy, steklovatnojj, chemical and other industries.Known mixture for the manufacture of corundum refractories containing 45% of the grains of 0.5 to 3 0.5 to 2 mm), 10% of the grains fraction 0.06 to 0.5 mm and 45% of the grain fraction of less than 0.06 mm, and part of it is connecting part includes chamotte, corundum (or oxide), alumina and Distin-sillimanite concentrate 
The disadvantages of such structure shall be considered its low manufacturability due to the lack of mineral plasticizer (clay, kaolin), for pressing such refractories, it is necessary to introduce organic plasticizer and high specific pressure presses and dispensing components, pressing raw.Closest to the proposed charge on a set of attributes (the prototype) is the mixture for the manufacture of refractory products with an irregular grain structure that includes the following components, wt.Granular refractory filler fraction 0.5 mm 40 80
Binder 5 10
Mix joint grinding faction 0.09 mm 15 50
the mixture of a joint grinding contains, by weight. corundum 55 80, alumina 2 15 and clay 15 30 
Improving manufacturability, the authors introduce the composition of the charge of the clay component (mineral plasticizer). It is well known that the introduction of the clay component in the manufacture of corundum refractories reduces their technical properties: building strength and volume stability at high temperatures. In the invention it is proposed to link the free silica formed during thermal decomposition of kaolinite clay component (education primary mullite) in the secondary mullite. The reaction of formation of secondary mullite begins at temperatures above 1450oC, therefore, for the completion of all physical and chemical processes firing refractories should be carried out at 1560 - 1620oC.The invention in comparison with the prototype allows acteristic refractories. This result is achieved by the fact that in the charge for the manufacture of refractories with discontinuous grain composition contains, by weight.Granular refractory filler fraction 0.5 mm 40 60
Mix joint grinding faction Rest of 0.09 mm
the mixture of a joint grinding contains, by weight. corundum 40 63,5, alumina 0,5 25, refractory clay or kaolin 20 30, zirconium dioxide else (but not less than 5).Mix joint grinding produced in a pipe or vibratory mill (size fraction of less than 0.09 mm).The mechanism of formation of mullite ligament in corundum refractories of the proposed structure is that the formation of zircon from the free silica formed during thermal decomposition of kaolin,
3(Al2O32SiO22H2O) - 3Al2O32SiO2+ 4SiO2< / BR>and added zirconium dioxide is an intermediate stage of initiation:
ZrO2+ SiO2ZrO2SiO2< / BR>Further, decomposing at temperatures above 1450oC zircon supplies free silica for education in conjunction secondary mullite with more active participation in the chemical ratio (compared to corundum alumina.Rasenia 30% kaolin in the mixture of a joint grinding (the maximum amount of kaolin in the mixture).In the kaolin contains, wt.Al2O340
In a mixture of a joint grinding:
40 0,30=12% Al2O3< / BR>56 0,30=16.8% of SiO2< / BR>Part of SiO2will be spent on the education of primary mullite. The ratio of the mullite Al2O3/SiO22,55.In primary mullite contact SiO212/2,55 4,71%
Remains unbound SiO2: 16,8 4,71 12,09
For binding in zircon (ratio of ZrO2/SiO22,03) will 5/2,03 2,46% SiO2remains 12,09 2,46 9,63% unrelated SiO2.To tie it in the mullite will need 2,559,63 24,56% alumina.2. The introduction of 20% kaolin in the mixture of a joint grinding (the minimum amount of kaolin in the mixture).In the kaolin contains, wt.40 0,20=8% Al2O3< / BR>56 0,20=11.2% of SiO2< / BR>Part of SiO2will be spent on the education of primary mullite. The ratio of the mullite Al2O3/SiO22,55.In primary mullite contact SiO28/2,55 3,14%
Remains unbound SiO2: 11,2 3,14 8,06%
For binding in zircon (ratio of ZrO2/SiO22,03) will 5/2,03 2,46% SiO2remains of 8.06 2,46 5,6% unrelated SiO2.To bind it all into a mullite patrimony technological bunch (technical solution of lignosulfonate density of 1.18 1.24 g/cm2), mix and add it to the mixture (the size fraction less 0,088 mm) composition, wt.Oxide 55
Zirconium dioxide 10
the resulting joint grinding of these components into a tubular ball mill or a vibration mill for 1 to 1.5 h at a ratio of balls material 10 to 1.The cooked mass is pressed and fired at 1520 1600oC.The calculation of the phase composition of the bundles shown in the example of the charge, the following.The amount of silica to be associated in zircon is calculated as follows.In the kaolin contains, wt.Al2O340
In a mixture of a joint grinding:
40 0,25=10% Al2O3< / BR>56 0,25=14% SiO2< / BR>Part of SiO2will go to the formation of mullite. The ratio of the mullite Al2O3/SiO22,55.SiO210/2,55 to 3.92%
Remains unbound SiO2: 14 3,92 10,08%
In the presence of 10% ZrO2in zircon contact (the ratio in zircon ZnO2/SiO22,03) 10/2,03 4.93 per cent silica.In the reaction of formation of secondary mullite will take only 10,08 is 4.93 5.15 silica. The ratio of the mullite Al2O3/SiO2 in the form of alumina, and the rest is in the form of corundum.At temperatures above 1500oC, after the dissolution of zircon in combination products is the following correlation phase, wt.ZrO2Tetragonal 10
Mullite 142,55 35,7
Corundum 100-10-35,7 54,3
The table shows the properties of the samples obtained for different compositions of the mixture. The mixture for the manufacture of refractories with an irregular grain structure that includes granular refractory filler fraction larger than 0.5 mm, and dispersed mixture of a joint grinding particles less than 0.09 mm, containing corundum, alumina and clay component, characterized in that the finely dispersed mixture contains as kaolin clay component and optionally Zirconia in the following ratio, wt.Corundum 40 63,5
Alumina 0,5 25
Kaolin 20 30
The Zirconia Else, but not less than 5
moreover, the mixture contains components in the following ratio, wt.Granular refractory filler fractions of more than 0.5 mm 40 60
Finely dispersed mixture of a joint grinding of the specified structure Ostalnoe
FIELD: refractory industry, in particular corundum parts for ferrous and non-ferrous metallurgy.
SUBSTANCE: on the step of batch preparation surface of fused corundum filler spheroid particles is damped with oleic or stearic acid in amount of 0.5-0.0 mass % in respect to total mass of phosphate binder. During agitation fine dispersed intergrinding mixture containing (mass %): Al2O3 47-80, ZrO2-SiO2 20-53, and phosphate binder (e.g. phosphoric acid or aluminum phosphate) is added. Batch contains (mass %): fused corundum filler 50-70; fine dispersed intergrinding mixture 30-50; phosphate binder over 100 % 5-10. Batch is homogenized, formed, solidified in air, baked at decomposition temperature of zircon concentrate, and cooled with isothermal holding at 1100-9000C.
EFFECT: corundum-based articles with improved strength and heat resistance.
7 cl, 2 tbl
FIELD: designs of glass melting furnaces.
SUBSTANCE: melt and cast materials on base of alumina-zirconium - silica contain, mass %: Al2 O3, 45 - 65; Zr02, 10.0 - 29.0;SiO2, 20.0 - 24.0 at relation SiO2/(Na2O + K2O), 4.5 - 8.0, the balance matters, 0.5 - 4.0. Such materials may be made of rejected products or from recovered waste materials and they may be used for making construction of glass melting furnaces, namely cross like members of regenerators.
EFFECT: lowered cost of raw materials, high operational properties of products.
11 cl, 4 tbl
FIELD: production of ceramic materials; methods of treatment of ceramics by high-temperature deformation; electrical engineering; mechanical engineering; manufacture of ceramic articles working at high temperatures under load.
SUBSTANCE: proposed method includes preparation of blank from ultra-dispersed powders of zirconium dioxide and aluminum oxide, preliminary sintering at temperature of 1300-1550C for no more than 1 h, high-temperature deformation at temperature of 1400-1600C and pressure of 3-10 Mpa and recrystallization annealing in vacuum at residual pressure of 5·10-5 mm Hg and temperature of 1500-1700C.
EFFECT: improved thermo-mechanical properties of ceramic articles.
3 cl, 3 ex
SUBSTANCE: invention pertains to production of fireproof products, mainly for glass-melting furnaces. The charge mixture consists of the following components in the given percentage mass ratios: ZrSiO4 8.5-10.5; Al2O3 72.0-75.0; TiO2 5.0-6.5; Cr2O3 5.5-7.0; ZnO 3.5-5.0; H3BO3 0.5-1.0. The products reach breaking point under pressure of 123-128 MPa, and have effective porosity of 0.15-0.2%.
EFFECT: increased durability and lower effective porosity of the products.
SUBSTANCE: invention pertains to composition of charge materials for production of stoves, thermal generating units, and metallurgical equipment. Charge material for production of refractory products contains the following components, wt %: mullite 31.0-34.0; corundum 30.0-32.0; kaolin 21.0-23.0; caustic magnesite 3.0-4.0; zircon 10.0-12.0.
EFFECT: enhanced heat stability of refractory products.
SUBSTANCE: method for production of heat resistant zircon-containing material includes mixing powder of zircon and aluminium represented by powder with fraction of less than 80 micrometre, in ball mill in liquid glass for 1-3 hours, moulding initial stocks and sintering at the temperature of 1600°C. Components in charge are in the following ratio, wt %: zircon concentrate 80-90, aluminium powder 10-20.
EFFECT: moulding certain phase composition in ceramic material, providing for high resistance to corrosion.
1 tbl, 3 dwg
SUBSTANCE: charge for production of an alloyed spinel material contains alumina, periclase, magnesium-alumina spinel, chrome oxide and zirconium dioxide, at the following ratio of components, wt %: alumina - 52.8-64.3; periclase - 22.7-25.2; magnesium-alumina spinel - 8.0-10.0; chrome oxide - 2.0-6.0; zirconium dioxide - 3.0-6.0. The alloyed spinel material contains a phase of alloyed spinel with the following composition Mg0.91-1.08(Al0.91-1.01Cr0.019-0.061)2O4 and phase of zirconium dioxide ZrO2, at the following ratio of phases, wt %: Mg0.91-1.08(Al0.91-1.01Cr0.019-0.061)2O4 - 94.0-97.0; ZrO2 - 3.0-6.0.
EFFECT: increased density and strength and reduced porosity of items.
2 cl, 5 ex, 1 tbl
SUBSTANCE: invention relates to a method of making articles from refractory ceramic material for use in microwave electronic equipment: furnace muffler, trays and components thereof. The surface of aluminium oxide particles is moistened with a surfactant, the aluminium oxide particles are mixed with kaolin in ratio of 3:1 (by weight) to obtain a homogeneous mixture of given composition, workpieces of the articles are formed by cold moulding, dried at normal temperature and fired in an oxidative medium as follows: raising temperature to 1650±20°C at a rate of 50±5°C/h, isothermic aging at that temperature for 3.0±0.5 hours and cooling to normal temperature at the same rate. Zirconium hydroxide sol with density of 1100-1180 kg/m3 and thickness of 1-3 mcm is applied onto the fired workpieces, completely dried at normal temperature and fired in an oxidative medium as follows: raising temperature to 1650±20°C at a rate of 100±5°C/h, isothermic aging at that temperature for 3.0±0.5 hours and cooling to normal temperature at the same rate.
EFFECT: high thermomechanical strength and, consequently, longer life of articles made from refractory ceramic material when used in microwave electronic equipment and ensuring stability of electrical properties thereof.
4 cl, 11 ex, 1 tbl
SUBSTANCE: invention relates to the fireproof industry. It can be applied for making of protective plasters, as well as monolithic linings of high temperature heat units. A fireproof mass for lining of the heat units includes electrocorundum, high-aluminous cement, zircon concentrate, a water solution of sodium polysilicate with the silicate modulus 6.5 with the following component ratio, wt %: electrocorundum 65-87.5; high-aluminous cement 5-10; zircon concentrate 5-20; water solution of sodium polysilicate 2.5-5.
EFFECT: increase of the thermal stability and mechanic properties.
SUBSTANCE: method involves anodic dissolving the metallic aluminium in the sodium chloride solution with the concentrationof 29±0.5 g/l in a coaxial electrolytic cell with electrode areas differing on two or more orders with the anodic current density of 20-160 A/m2 in the presence of zirconium ions in an amount providing the zirconium oxide content in the formed precipitate from 5 to 20 wt %, maintaining the resulting precipitate in the mother liquor for at least 48 hours, filtering and drying the sediment.
EFFECT: method allows to obtain highly dispersed aluminium-zirconium oxide systems with an average particle size of 20-50 nm, which can be used for producing ceramics of special purpose.
2 cl, 1 dwg, 1 ex, 1 tbl