Removing arsenic from anode slime by vacuum dynamic evaporation and vacuum dynamic flash reduction

In crude lead or copper electrorefining, the by-product anode slime is an important material of recycling precious metals. However, the existing methods for treating arsenic-rich anode slime are less than satisfactory not only for the removal effect of arsenic but also for the environment protection. Therefore, a new technology for treating arsenic-rich anode slime was proposed in this paper, namely the two-step process of vacuum dynamic evaporation (VDE) and vacuum dynamic flash reduction (VDFR). Through this two-step process, silver from the anode slime was left behind in distilland as the silver alloy, and the trivalent oxide of arsenic was evaporated in the distillate. The experimental results showed that the removal ratio of arsenic was 99.96%. Moreover, these vacuum technologies offer improvements in metallurgical and environmental performance. (C) 2011 Elsevier Ltd. All rights reserved.