Technology status and prospect of efficient tin recovery from tin secondary resources

As an important strategic resource, tin has irreplaceable applications in various fields due to its excellent physical and chemical properties. The gradual depletion of easily beneficiable tin resources and the low recovery efficiency of refractory tin ores increasingly aggravate the supply pressure of tin resources. Improving the comprehensive recovery and utilization efficiency of tin-bearing secondary resources can not only relieve the supply pressure of tin resources, but also reduce the corresponding environmental impact. This paper focuses on typical tin-bearing secondary resources, including tin middlings and tailings, waste printed circuit boards, tungsten smelting slag, tin alloy waste, and tin anode slime. The global distribution and consumption characteristics of tin resources are analyzed, and the current technical status of tin recovery processes for different tin secondary resources is comprehensively reviewed. Combined with the corresponding reaction mechanisms, the advantages, disadvantages and industrial application status of hydrometallurgy, pyrometallurgy, microbial leaching and combined processes are systematically compared. The development of short-process and high-efficiency tin recovery technologies helps improve the economic benefits of enterprises. On this basis, this study summarizes the major technical bottlenecks restricting the sustainable development of the tin secondary resource utilization industry, including lengthy technical processes and high processing costs in tin smelting, refining and purification. Future development directions of tin secondary resource utilization focus on the preparation of high-value-added products and high-purity products such as sodium stannate and stannous sulfide, so as to improve the utilization benefit of tin waste materials. This research provides a reference for the virtuous cycle and sustainable development of the tin industry.