シュウ酸による含 Co 有機相からの晶析逆抽出への超音波の利用

抄録

The precipitation stripping phenomena of cobalt oxalate from cobalt-loaded D2EHPA solution were investigated with and without ultrasound irradiation. Morphological variation of precipitated cobalt oxalate was examined with processing factors such as pH value and C2H2O4 concentration under three kinds of mixing modes encountered in crystallization operation ; 1) precipitation synthesis of cobalt oxalate in aqueous solution mixed with an impeller, 2) precipitation stripping from cobalt-loaded organic solution and 3) precipitation stripping from cobalt-loaded organic solution under ultrasound irradiation. The shape of precipitate was rod-like and not significantly influenced by any mixing mode. The size of cobalt oxalate particles obtained without ultrasound irradiation was at most 10μm in major axis. The aspect ratio of rod-like particles, moreover, tended to increase with increasing in H+ and C2H2O4 concentrations in the stripping solutions. Meanwhile, the ultrasound irradiation significantly decreased particle size of cobalt oxalate. It was less than 1μm in major axis, when the [C2H2O4]a concentration was lower. On the other hand, ultrasound irradiation induced fibriform precipitation when the [C2H2O4]a concentration was higher.