Extraction of valuable metals from minerals and industrial solid wastes via the ammonium sulfate roasting process: A systematic review

The concept of a "low-carbon economy" will drive the accelerated deployment of clean energy technologies, which, in turn, will lead to rapid growth in demand for metal resources. In addition to traditional mineral re-sources, industrial solid wastes commonly contain numerous valuable metals, however, owing to their complex composition, improper treatment may cause serious environmental pollution. Considering the requirement for sustainable development of society, there is an urgent need for a clean, efficient, economical, and sustainable technology for the extraction of valuable metals from various minerals (especially low-grade mineral resources and tailings) and industrial solid wastes. The ammonium sulfate roasting method has the advantages of high metal recovery, good reaction selectivity, environmental friendliness, and low energy consumption, which is a promising roasting technique. Nevertheless, its promotion is hampered by the absence of a comprehensive and systematic understanding. This article provides a comprehensive overview of recovering valuable metals from various minerals and industrial solid wastes by ammonium sulfate roasting, the mechanism of extracting valu-able metals is summarized, and the potential of the method is discussed. Furthermore, based on the above comprehensive discussion, future research is suggested to focus on improving the utilization of ammonium sulfate and the recovery of ammonia and sulfur. This technology provides new ideas for the effective treatment of low-grade mineral resources, tailings, and industrial solid wastes, and is of great significance to the clean pro-duction of society.