Abstract: Cyanide tailings from a gold smelter in Hunan contains more than 5 g/t of gold,and its main phase is hematite,quartz and muscovite.The intergrowth of quartz with inclusion of pyrite and gold is the important reason that gold can not fully contact with cyanide.In order to solve this problem,the conditioning tests of alkaline hydrothermal leaching for desilication of cyanide tailings are carried out.The results show that under the concentration of sodium hydroxide 25%,the volume mass ratio 2 L/kg,the leaching temperature at 160 ℃,the stirring speed 400 r/min,and the leaching time for 3 h,the desilication rate reached 57.6%.Through the process of desilication,the leaching rate of gold is increased from 4.7% to 38.4%.

Key words: Cyanide tailings, Alkaline hydrothermal process, Quartz, Physical inclusion