Study on the mechanism of ultrasonic enhanced removal of zinc and germanium from lead residue

Lead residue is the residue from the leaching process of zinc oxide dust containing germanium, which comprises a certain amount of valuable elements such as zinc and germanium. Conventional water washing treatment cannot effectively remove zinc and germanium from lead residue, resulting in a backlog of zinc and germanium in the system and raising production costs for enterprises. By using a dilute sulfuric acid solution and introducing ultrasonic waves for enhanced washing, the easily separated zinc and germanium are basically removed, while the residual zinc occurred as ZnS and germanium wrapped in lead sulfate are difficult to elute. The removal efficiency of zinc and germanium can reach 53.82% and 50.24%, respectively, which are 12.67% and 6.10% higher than conventional acid washing efficiency, and 31.10% and 22.51% higher than conventional water washing efficiency. During water washing, the hydrolysis of Zn2+ and Fe3+ results in low elution efficiency. While in pickling process, hydrolysis can be effectively inhibited. When use ultrasonic to enhance sulfuric acid washing, some ZnS dissolves, while the silica gel colloid that adsorbs germanium is destroyed, and germanium is released into the solution again, thus improving the removal efficiency of zinc and germanium. This article has reused more than half of the residual zinc and germanium in lead residue, and points out the direction for further reducing zinc and germanium residues in lead residue. It is of great significance for the comprehensive utilization of zinc and germanium resources.