采用Na2SO3溶液从硒渣中选择性浸出Se及其动力学

采用SO2还原沉金后液制得硒渣,再用Na2SO3选择性浸出硒渣,使Se得到有效分离;通过研究浸出过程中Se浸出率随时间的变化,建立该反应的动力学方程,确定Na2SO3溶液浓度、液固比、搅拌速度及反应温度对Se浸出率的影响,并计算相应的表观活化能。结果表明:增加Na2SO3溶液浓度和升高反应温度可以较大幅度提高Se的浸出率,液固比和搅拌速度对浸出Se的影响较小;Na2SO3浸出Se过程为Avrami模型混合控制,其特征参数n和表观活化能E分别为0.235和20.847 kJ/mol,Se的浸出率受反应温度的影响较大。

Selective leaching Se from selenium residue by Na2SO3 solutions and leaching kinetics

Selenium was effectively separated from selenium residue.The selenium residue was prepared from the solution after precipitating gold by SO2 reduction,followed by Na2SO3 selective leaching.The effects of Na2SO3 concentration,liquid and solid ratio,stirring speed and reaction temperature on Se extraction were confirmed with the change of Se leaching ratio during the leaching process of Se by Na2SO3.The kinetics equation was established and the corresponding apparent activation energy was calculated.The results indicate that Se leaching ratio increases greatly with increasing Na2SO3 concentration and reaction temperature.The liquid and solid rate and stirring speed have little influence on Se extraction.The kinetics of leaching Se from selenium residue follows the Avrami model and the leaching process is hybrid controlled.The apparent activation energy of leaching Se and the feature parameter of Avrami equation are determined to be 20.847 kJ/mol and 0.235,respectively.The reaction temperature has great influence on Se leaching rate.