Low Grade Silver Concentrate Pre-oxidation Leaching Of A Pilot Study

Silver is a kind of important precious metal element. In the world and even the long historyof our country, not only served as a international currency, jewelry and accessories, but also inthe process of industrial development is now also serve as an important role, for our nationaleconomy has an important role. The whole of human society's political, economic, trade made asignificant contribution.The current situation of leaching silver in domestic and international silver mineral wassummarized up in this study. In order to improve the utilization, and to achieve maximumdevelopment of mineral resources, here we propose two low-grade silver concentrate leachingprocess.(1)Cyanide Leaching ,Based on the analysis of low-grade silver ore mineralogy andchemical . The effects of grinding fineness, stirring speed, cyanide concentration, liquid to solidratio, leaching time and ammonium sulfate pretreatment—cyanide leaching experiment on theleaching rate of silver concentrate. the optimum conditions are obtained as follows: the grindingfineness of -0.038mm 80% ,10h alkaline pretreatment of ammonium sulfate. the first stage: thestirring speed 500r/min, liquid to solid ratio 2:1, the leaching time 48h, cyanide concentration0.15mol/L. The second stage:liquid-solid ratio of 2:1, the leaching time 24h, cyanideconcentration of 0.1mol/L, the silver leaching rate is about 81.65%..(2)Thiosulfate leaching, In low-grade silver concentrate thiosulfate leaching test process,The effects of concentrations of thiosulfate, ammonia concentration, copper sulfate concentration,solid to liquid ratio, stirring speed, extraction time on the leaching rate of silver concentrate。theoptimum conditions are obtained as follows: the first stage: stirring speed 500r/min, the grindingfineness of -0.038mm accounted for 80%, sodium thiosulfate 0.2mol / l, ammonia 1mol / l,copper sulfate 0.01mol / L, stirring speed 500r/min, liquid to solid ratio of 4:1, Leaching time 12h,leaching temperature 55℃. The second stage: sodium thiosulfate 0.1mol / l, ammonia 0.5mol / l,copper sulfate 0.005mol / L .liquid to solid ratio of 4:1, extraction temperature 55℃, extractiontime of 2h. the silver leaching rate is about 88.85%.In the experiment, thiosulfate leaching kinetics of low-grade silver concentrate was topreliminary explored. the conclusion that the leaching process of silver from the concentrate isunder the control of mass-transfer of solid .and the velocity equation of leaching silver is(?), a lot of work in the experiment must be done to make sure of thek'. the leaching high-point velocity of stir is 500r/min, the leaching apparent activation energy is29658J/mol .