Reduction Leaching of Arsenic from Copper Smelting Flue Dust
摘要
As the high-pollution material produced in the copper smelting process, the treatment of flue dust has received more attention in recent years, but has mainly focused on the recovery of valuable metals such as copper and lead; the behavior of arsenic has been neglected. Extraction is mainly carried out under high acidity, which limits treatment of the solution. The arsenic in leaching residue not only causes the transfer of contaminants but also reduces the price of the lead sulfate residue. With the improvement of copper smelting technology in China, the characteristics of flue dust have changed significantly. In this study, the effects of factors on the extraction of Cu, Zn, As, and Cd from bath-smelting flue dust were studied, including sulfuric acid concentration, reaction time, and temperature. Based on the mineralogical analysis results, copper and zinc mainly exist as sulfates and oxides, and arsenic mainly exists as oxide and arsenate in the bath-smelting flue dust. Under normal temperature, with initial H2SO4 of 180 g/L and reaction time of 1 h, the extraction of Cu, Zn, As, and Cd was 99.27%, 98.80%, 90.13%, and 90.39%, respectively. To decrease the arsenic content in the lead residue and reduce the acidity of the solution, a two-stage reduction leaching technology was introduced. At 110°C, with initial acidity < 20 g/L and the reduction of SO2, the extraction of Cu, Zn, As, and Cd can reach 98.42%, 98.95%, 96.52% and 90.62%, respectively.