| 摘要 |
PURPOSE:To reduce both costs of a raw material and production in a purification step, by treating an aqueous solution after forming precipitates with NH3 gas in a process for producing the titled oxide by reacting the respective component elements in an aqueous solution with oxalic acid in the presence of ethanol and thermally decomposing the resultant precipitates. CONSTITUTION:An aqueous solution containing ions of elements to constitute a perovskite type oxide expressed by the formula ABO3 (A is one or more of Ba, Sr, Ca and Pb; B is one or more of Ti and Zr) is reacted with oxalic acid in the presence of ethanol and/or isopropanol to give a precursor of the above-mentioned oxide as coprecipitates. The resultant aqueous solution con taining the coprecipitates is stirred to keep the coprecipitates in the suspended state, and NH3 contained in a gas cylinder is returned to almost ordinary pres sure and blown into the above-mentioned aqueous solution containing the suspended coprecipitates. According to this process, nitric acid produced in the formation of oxalates, TiO(NO3)2, etc., and the unreacted oxalic acid are neutralized, and the required amount of the element (B) ions can be reduced to almost equivalent amount. Problems in corrosion of distillation columns, etc., are eliminated.
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