| 摘要 |
PURPOSE:To obtain an excellent grinding material and a fire resistant material excellent in strength and heat resistance by heating an electrofused alumina granule at a high temp. to deposit titanium forming a solid solution and to form aluminum titanate on the surface and quenching. CONSTITUTION:The electrofused alumina small in impurities except 0.1-1.5wt.% Ti expressed in terms of TiO2 and Cr and high in alumina purity is obtained by adding a TiO2 source such as titanium oxide (rutile type or anatase type), a titanium slug (TiO2=80wt.%) into an alumina by Bayer method and fusing in a electric furnace or by melting and strongly reducing bauxite with a reducing material. The surface of the electrofused alumina granule is coated with aluminum titanate having 5-15mum thickness by pulverizing the electrofused alumina high in alumina purity, feeding to a vessel after adjusting the granule to a prescribed particle size, heating at 1300-1700 deg.C in an electric furnace, tunnel continuous furnace, rotary kiln or the like, holding at 1400 deg.C for 30min and at 1600 deg.C for >=10min and quenching from 1300 deg.C to 750 deg.C in the rate of >=300 deg.C/hr to prevent decomposing aluminum titanate formed on the surface of the granule. |
