Experimental Researches On Recovering Gold And Silver From Cyanide Residue

With the gold mining scale being expanded and the time being prolonged, the gold resources in China have been exhausted, high-grade gold become scarce, while the accumulation of cyanide residue as the gold tailings increased year by year, which contain residual valuable elements such as gold and silver etc., causing serious waste of resources. With the development of technology of gold extraction, the residual gold in cyanide residue as secondary resources can be comprehensive recovered, which is obvious economic benefit.The gold grade in the cyanide residue is 3~5 g/t in a certain gold mine in Gansu, which is of great recovery value, floatation experiments are carried out to recover gold and silver from it. The oxidization level of sulfide ore in cyanide residue is high as long-term storage, and cyanide residue contains a large amount of inhibitor sodium cyanide of sulfide ore. As a result, with only sulfide collecting agents, the recovery of gold is only around 60%. In order to strengthen the floatation of the oxidized ore, further improve the recovery, effective collecting agent XJD-10 of oxidized ore in cyanide floatation has been developed. The experimental results show that butyl xanthate compounded with XJD-10 can obviously enhance the floatation efficiency; with regrinding fineness -200 mesh of more than95%, copper sulfate as activator, only butyl xanthate in roughing, butyl xanthate compounded with XJD-10 in scavenging, through one roughing floatation, two cleaning floatation and four scavenging floatation flowsheet, the gold concentrate with the grade of 104.69g/t, the gold recovery of 84.13% and the silver recovery of 73.42% was obtained; the flotation indices is very good. Study on the cyaniding process used to recovery gold and silver from cyanide residue has been taken at the same time. The results show that with regrinding fineness -200 mesh of 99.45%, slurry density 40%, the dosage of protective alkali lime 4000g/t, dosage of sodium cyanide 2000 g/t, the leaching rate of gold is around 80%, which is about the same as the result of floatation, while cyaniding process having the large power consumption, high cost and more difficulty to deal with environmental protection, so the floatation recovery of gold and silver being recommended.The floatation flowsheet developed for the cyanide residue from a certain gold mine in Gansu was technologically advanced and economically reasonable, which has reference values for the recovery of gold and silver from other cyanide residue.