Abstract:
China has maintained the world’s highest zinc production for many years, which has generated a tremendous amount of zinc slag, and 60% of which has not been effectively treated. Most of this slag is zinc leaching residue produced by the hydrometallurgical processing of zinc. The accumulation and storage of zinc leaching residue requires large tracts of land and harmful elements like arsenic and cadmium in the residue contaminate the surrounding soil and groundwater. From another perspective, zinc leaching residue represents a solid waste resource with a very high comprehensive utilization value. For example, many valuable metals are present in zinc leaching residue, including zinc, lead, and silver, which have high recovery values. In addition, zinc leaching residue can be fully utilized to produce cement, glass, ceramics, and a range of chemical materials. The comprehensive recovery and total material utilization of zinc leaching residue would help to significantly reduce the burden of its storage. This paper summarized research progress on the recovery of valuable metals from and the total material utilization of zinc leaching residue. Two main methods were used to recover valuable metals from this residue: pyrometallurgical and hydrometallurgical processes. Based on a detailed comparative analysis of the advantages, disadvantages, and feasibility of various typical recovery processes, this paper proposed a combined method of bioleaching and chloride leaching for the efficient extraction of zinc, lead, and silver from zinc leaching residue. This combined method has good applicability to different types of zinc leaching residue and good prospects for industrial application. In addition, this paper introduced the progress achieved in the total material utilization of zinc leaching residue and the future development prospects for utilization technologies. The total material utilization of zinc leach residue should be developed to product high-performance, sophisticated, environment-friendly and energy-efficient materials. Greater economic benefit can be gained while realizing clean production in the zinc industry.