Release Kinetics of Ba and Pb Contained in WPCBs During the Traditional Hydrometallurgical Process

The release kinetics of heavy metals (Ba and Pb) contained in WPCBs, during the traditional hydrometallurgical process, were investigated in this study. The effects of different conditions, i.e. particle size, solid/liquid ratio, amount of H2O2 and HNO3, HNO3 concentration, react time and temperature, on Ba and Pb release were examined. The highest release rates of Ba and Pb were obtained. For Ba, particle size was <100 mesh, solid/liquid ratio was 1:2, HNO3 concentration (HNO3:H2O, v/v) was 1:2, amount of both H2O2 and HNO3 were 6 mL, react time was 4 h and temperature was 50 °C For Pb, particle size was 40-20 mesh, solid/liquid ratio was 1:3, HNO3 concentration was 1:3, amount of both H2O2 and HNO3 were 4 mL, react time was 2 h and temperature was 50 °C. The results showed that the highest release concentration of Ba and Pb were up to 76.89 g/L and 2.18 g/L, respectively.