Recent advances in the recovery of germanium during the zinc refining process

Germanium plays an essential role in many high-tech fields because of its excellent electrical and optical properties. For germanium from primary resources, approximately 51.7% of it was sourced from zinc concentrate, which is one of the most important sources of germanium recovery. The germanium recovery process is mainly divided into two parts: leaching and separation, including acid-base leaching, tannin precipitation, extraction, ion exchange, supporting liquid membrane and chlorination. However, the total recovery efficiency for germanium is low, accompanied by high energy consumption and high impurity content. Therefore, there is an urgent need to utilize germanium in zinc concentrate globally using efficient and low-consumption green processes. Detailed analysis of the nature of insoluble phases in minerals and mechanisms such as coordination, external field enhancement, precipitation, and extraction are crucial to solving the low recovery rate of germanium. Accordingly, this paper provides a systematic overview of the basic properties, key technologies and recent advances for leaching and separation of germanium, with particular emphasis on the study of germanium species and coordination reactions. Finally, some recommendations are provided to promote the development of the comprehensive utilization of germanium in the zinc refining process.