Separation and recovery of arsenic from As, Cu, and Zn rich leaching liquor using a reduction-crystallization approach

As, Cu, and Zn rich leaching liquor is generated in the leaching process of copper dust, which contains various metals with high recovery value. Herein, an approach for the direct separation and recovery of arsenic from As, Cu, and Zn rich leaching liquor was proposed. The approach includes two steps, namely SO2 reduction and arsenic crystallization. The factors affecting the reduction of As(v) to As(iii) were investigated, including the pH, SO2 dosage, and reduction temperature. In the crystallization stage, the impacts of sulfuric acid consumption and temperature on the crystallization of arsenic (As2O3) were studied. The results show that the optimal H+ concentration, temperature, and SO2 input for the arsenic reduction were 3.95 mol L-1, 45 degrees C, and 1.14 L g(-1) As(v), respectively. While the optimal temperature and sulfuric acid dosage in As recovery process were 5 degrees C and 0.1 L L-1 leaching liquor, respectively. Under these conditions, the As2O3 recovery percentage reached 96.53%, and the losses of Cu and Zn were only 3.12% and 0.75%, respectively. The precipitate contained 96.72% of As2O3, 0.83% of Cu, and 0.13% Zn. Compared with the traditional technologies, this new method can improve the recovery efficiency of As2O3 and reduce the loss percentage of other valuable metals (Cu and Zn).

Automated summary

A method for the direct separation and recovery of arsenic from As, Cu, and Zn rich leaching liquor was proposed, which includes two steps: SO2 reduction and arsenic crystallization. Optimal conditions for arsenic reduction and recovery were determined, leading to high recovery efficiency of As2O3 and low loss percentage of Cu and Zn. Compared with traditional technologies, this new method offers improved recovery efficiency and reduced loss of valuable metals.