Ultrasound Emulsification for precipitation Stripping of Cobalt Oxalate from Cobalt-loaded Organic Solution

摘要

The precipitation stripping phenomena of cobaltoxalate from cobalt-loaded D2EHPA solution were investigatedwith and without ultrasound irradiation. Morphological variationof precipitated cobalt oxalate was examined with processingfactors such as pH value and C2H2O4 concentration under threekinds of mixing modes encountered in crystallization operation; 1)precipitation synthesis of cobalt oxalate in aqueous solution mixedwith an impeller, 2) precipitation stripping from cobalt-loadedorganic solution and 3) precipitation stripping from cobalt-loadedorganic solution under ultrasound irradiation. The shape ofprecipitate was rod-like and not significantly influenced by anymixing mode. The size of cobalt oxalate particles obtained withoutultrasound irradiation was at most 10?m in major axis. The aspectratio of rod-like particles, moreover, tended to increase withincreasing in H+ and C2H2O4 concentrations in the strippingsolutions. Meanwhile, the ultrasound irradiation significantlydecreased particle size of cobalt oxalate. It was less than 1?m inmajor axis, when the [C2H2O4]a concentration was lower. On theother hand, ultrasound irradiation induced fibriform precipitationwhen the [C2H2O4]a concentration was higher.