| 摘要 |
PURPOSE:To obtain sintered particles of alumina having uniform spherical shape and size, high quality and high strength with high yield by sintering spherical particles obtd. by injecting a slurry comprising Al2O3 and aq. soln. of a binder into a soln. of a curing agent. CONSTITUTION:Al2O3 having <=30 mean particle size and/or Al(OH)3 is mixed with aq. soln. of binder comprising a water-soluble polymer such as sodium alginate, and a slurry having 0.5-5.0wt% concn. of the binder and 20-2,000cp viscosity is obtd. The slurry is injected or dropped into a soln. contg. 0.5-5.0wt% curing agent [e.g. Al2(SO4)3] for curing said binder to form spherical particles having 0.05-10mm particles size, whereby a cured film is formed on the spherical particle by allowing the binder to react with the curing agent on the surface of the spherical particle. The particles are then, if necessary, washed with water and mineral acid to remove Na component, dried and sintered at 1,400-1,900 deg.C. |
