Recovery of silver from an refractoriness silver ore by thiosulphate leaching

Free milling gold and silver ores are exhausted gradually, and instead there is a tendency towards the utilization of refractory ores. Especially Silver ores have distinct mineralogical prosperties and complex forms which makes of Ag from these ores difficult. The cyanide leaching used conventionally in gold and silver ores for less efficient in this type of refractory ores, and because of the toxic effect of cyanide. Thiosulfate (S2O3-2) leaching is often considered as an alternative promissimg from a refractory silver ore which is affective to a limited extent by foreign cations/anions has been projected as an alternative. In this study, high silver recovery is aimed thiosulfate leaching as an alternative to cyanide leaching. The effects of parameters were investigated after fine grinding by means of stirred mill to enable more contact with the silver phases. Experimental design techniques were utilised. The result have shown that as 98% silver from refractory ore could be extracted as a result of thiosulfate leaching after ultra-fine grinding as pre-treatment. Also, the thiosulfate consumption was determined to be 93.8 kg/ton. In cyanide leaching, the silver recovery was %72.6 with a cyanide consumption of 4.81 kg/ton. Can be concluded that thiosulfate is more effective in silver recovery but at the expense of high reagent comsumption.