High-gravity reactive precipitation process for the preparation of barium titanate powders

Abstract

The invention relates to a process for the preparation of fine barium titanate (BaTiO) powders. The process comprises introducing an aqueous solution (I) containing salts of barium and titanium, and an aqueous basic solution (II) containing an inorganic or organic base separately and simultaneously into a high-gravity reactor with the high-gravity level of 1.25G to 12,500G and performing the reaction of the solution (I) with the solution (II) at a temperature of from 60 to 100° C. The solution (I) is preheated to a temperature ranging from 60° C. to 65° C. and the solution (II) is preheated to a temperature ranging from 60° C. to 100° C. respectively prior to the reaction, in which the Ba/Ti molar ratio in the solution (I) is more than 1 and the concentration of the base in the solution (II) is such that the reaction mixture is maintained at a constant OHconcentration, preferably a pH value of about 14. The reaction product is separated by filtering and washed with deionized water to remove the impurity ions and excessive barium ions, and then dried to obtain BaTiOpowders. Said powders consist essentially of crystalline, primary particles having a uniform particle size ranging from 5 to 200 nm, an approximately spherical morphology and a high sintering activity.