Kinetics of Co（II） extraction from sulfate aqueous solution by the sodium salt of di-decylphosphinic acid （Na-DDPA） was studied using a modified Lewis cell to disclose the mechanism of extraction. Parameters affec...Kinetics of Co（II） extraction from sulfate aqueous solution by the sodium salt of di-decylphosphinic acid （Na-DDPA） was studied using a modified Lewis cell to disclose the mechanism of extraction. Parameters affecting the extraction rate, such as stirring speed, temperature, interfacial area, Na-DDPA concentration and Co（II） concentration, were investigated, respectively. The effect of diffusion resistance on extraction rate was negligible when the stirring operation was conducted in a plateau region of 95-110 r/min. Extraction rate increased with the increase in the temperature or specific interfacial area. The activation energy E was calculated to be 32.75 kJ/mol. These suggested that rate controlling mechanism of Co（II） extraction by Na-DDPA was chemical reaction regime and the rate-determining step of Co（II） extraction was chemical reaction at the interface. The initial extraction rate also increased with the increase in the concentrations of Na-DDPA and Co（II）. The extraction rate equation and mechanism of Co（II） extraction by Na-DDPA were proposed.展开更多
基金Projects (50734005, 51074096) supported by the National Natural Science Foundation of ChinaProject (2012AA06A110) supported by the Hitech Research and Development Program of ChinaProject (2012BAB07B01) supported by the National Key Technology R&D Program, China
文摘Kinetics of Co（II） extraction from sulfate aqueous solution by the sodium salt of di-decylphosphinic acid （Na-DDPA） was studied using a modified Lewis cell to disclose the mechanism of extraction. Parameters affecting the extraction rate, such as stirring speed, temperature, interfacial area, Na-DDPA concentration and Co（II） concentration, were investigated, respectively. The effect of diffusion resistance on extraction rate was negligible when the stirring operation was conducted in a plateau region of 95-110 r/min. Extraction rate increased with the increase in the temperature or specific interfacial area. The activation energy E was calculated to be 32.75 kJ/mol. These suggested that rate controlling mechanism of Co（II） extraction by Na-DDPA was chemical reaction regime and the rate-determining step of Co（II） extraction was chemical reaction at the interface. The initial extraction rate also increased with the increase in the concentrations of Na-DDPA and Co（II）. The extraction rate equation and mechanism of Co（II） extraction by Na-DDPA were proposed.
