Comprehensive Recovery of Tin and Associated Metals from Tin Tailings in the Gejiu Area, China, by a Combined Beneficiation and Metallurgical Route

摘要

Tailings from tin beneficiation are important resources in the Gejiu area, Yunnan Province, China. Their properties lead to difficulties in separation: for example, they are low-grade and fine-grained, cassiterite being closely intergrown with limonite. It is difficult to obtain a high-grade concentrate by conventional beneficiation. The development of volatilization has proved promising and a specific method that combines beneficiation with metallurgical treatment has now been put into effect. The feed (tailings) is classified into two fractions by hydrocyclones. The +19 micrometers fraction is subjected to gravity and magnetic concentration. The -19 micrometers fraction is sent to flotation after desliming by selective flocculation and other methods. Both circuits can produce rich tin middlings, lower-grade tin middlings and tailings. The products of beneficiation are treated by volatilization. The rich tin middling is volatilized by sulphidization fuming and the lower-grade by high-temperature chloridization, associated metals being comprehensively recovered in this way. The slag from sulphidization fuming and roasted pellets from chloridization can be used as feed for a blast-furnace to recover the iron values. The total recovery from the tailings feed to metal is about 45-55% of the tin.