Method for extracting germanium from high-impurity low-grade complex zinc oxide powder

The invention provides a method for extracting germanium from high-impurity low-grade complex zinc oxide powder, and belongs to the technical field of hydrometallurgical processes. The method comprises the following steps of: under the process conditions that the PH value is 0.5 to 1.5 and the temperature is 55 to 75 DEG C, adding sulfite into aqueous solution of zinc sulfate which contains 8,000to 15,000mg/L iron, 300 to 1,000mg/L Fe , and 30 to 135mg/L germanium so as to convert Fe into Fe , complexing and precipitating the germanium by adopting tannic acid to ensure that the germanium in the aqueous solution of zinc sulfate is subjected to a phase change reaction to form [GeO(C75H52O46)2 ], pretreating, and calcining in a calcining kiln to obtain a germanium concentrate with the germanium content of between 8 and 22.36 percent which is used for producing germanium series products; and removing iron from solution of zinc sulfate obtained after the separation, and feeding into the conventional electrolytic zinc production system to recover valuable metals such as zinc, cadmium, indium and the like. By the method, the interference of the Fe to a multi-metal recovery system can be effectively avoided, the production cost is reduced, and the smooth production process flow is ensured. The method has great significance for comprehensively recovering and recycling the valuable metals in low-grade high-impurity complex zinc oxide raw materials.