China Nonferrous Metallurgy

Gallium and germanium are important rare metals, and the comprehensive recovery of gallium and germanium from the zinc metallurgy process has become an important source for the metals. At present, acid leaching process is mainly used to recover gallium and germanium, with low recovery rate and resource utilization rate. In this paper, based on the properties of gallium and germanium amphoteric substances, the experimental study on the recovery of gallium and germanium from zinc refinery residues was carried out by alkali leaching-reduction volatilization process,andthe following main conclusions are obtained.The single factor optimum process conditions of alkali leaching test are as follows, NaOH concentration 4mol/L, reaction temperature 90℃, liquid-solid ratio 8mL/g, stirring speed 400r/min. Under these conditions, the leaching rates of gallium and germanium of zinc refinery residues reach 91.25% and 78.95%, respectively.Enhanced ball milling leaching does not improve the leaching rate of gallium and germanium.The single factor optimum process conditions of reduction volatilization test were as follows, temperature 1200℃, pulverized coal dosage 30%, volatilization time 4h. Under these conditions, the volatilization rate of germanium in alkaline leaching residue reached 91.02%.The volatile residue and calcium arsenate residue produced by the process are returned to the pyrometallurgical lead smelting system to comprehensively recover valuable metals such as copper and arsenic, and the harmless treatment of the residue is realized.The volatile residue and calcium arsenate residue produced by the process are returned to the pyrometallurgical lead smelting system to comprehensively recover valuable metals such as copper and arsenic.The method of recovering gallium and germanium in this paper can provide reference for similar enterprises to recover gallium and germanium from zinc metallurgy process.