Patent RU-2280016-C2 (RU)
Inventor: IVANITSKIJ MIKHAIL ANTONOVICH
IPC: C04B35/101
Filed: 2004-10-12
Granted: 2006-07-20
Abstract: FIELD: refractory materials industry; charges and the methods of production of the corundum refractory materials. 
     SUBSTANCE: the invention is pertaining to the refractory materials industry and may be used at manufacture of the high-density special-purpose corundum refractory materials for the critical blocks of the lining of the heat aggregates working in the conditions of the variable oxidative-reducing or the reducing gas medium. The technical result of the invention is the increased heat resistance, erosion resistance and the reduced porosity, reduction of the reject during their heating and the following cooling within the whole temperature range of the furnace operation. The charge for production of the corundum refractory materials includes the components in the following ratio (in mass %): the filling material: the electrocast corundum of the fraction of 3-1 mm - 20-25 %, the electrocast corundum of fraction of 1-0.5 mm - 30-35 %, the electrocast corundum of fraction of 0.5-0.1 mm - 20-25 %; the binding component of the charge: aluminum oxide with the particles size of less than 5 microns - 15-20 %, aluminum oxide dispersible with the particles size of less than 1 micron containing magnesium oxide with the particles size of less 1 micron - 5-10 %; the binding material - 2.5-2.8 % of the dry charge. At that the charge contains: AL 2 O 3  - no less than 99.0 %, Fe 2 O 3  - no more than 0.05 %, SiO 2  - no more than 0.5 %. As the binding material use hydrosol AL 2 O 3  in the combination with lignosulfonate and the polyvinyl alcohol taken in the ratio of 70-74.8 : 25-29 : 0.2-1,0 %. The method of manufacture of the corundum refractory materials includes: the charge preparation by mixing of the components of the filling material with the binding component, the subsequent connection with the refractory bond, molding of the products including the filling of the charge in the press-mould, pressing, the seasoning, the drying, the  roasting and refrigeration. All the stages of the products molding are conducted under action of the vibrating tool  mounted directly on the press mold body. At that at the stage of the charge filling the amplitude of the vibrations is set equal to 0.5-1 mm and the vibrations intensity - λ < 1, the products pressing is conducted at the pressure of 80-100 MPa, the amplitude of the vibrations of 0.25-2 mm and at the vibrations intensity - λ > 1, the release of the products from the moulds is exercised at the amplitude of the vibrations of 0.1-0.5 mm and the vibrations intensity - λ < 1. The roasting conduct in the batch furnace at the rarefaction of no less than 50 Pa during its heating up to the temperature of 1730-1750°C, and refrigeration of the refractory materials is conducted in the furnace simultaneously with its cooling-down by the natural convection till achievement of the internal temperature of the furnace of 600°C and further - till the final cooling-down with the help of the forced feeding of the atmospheric air from the furnace section. 
     EFFECT: the invention ensures the corundum refractory materials increased heat resistance, erosion resistance, reduced porosity, reduction of the reject during their heating and cooling. 
     9 cl, 3 tbl, 1 ex