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Microbial leaching of low grade copper ore hydrometallurgical copper in the leaching process , due to the action of acid , in addition to copper , Fe and other impurities also will be dissolved and the gradual accumulation of normal when Fe3 reaches a certain concentration , harm leaching process . In this study, the mechanically activated pyrite bio- heap leaching solution of sodium thiosulfate processing high-speed rail , and recovered by processing the copper sulfate . Mechanically activated pyrite , reaction temperature 80 ° C , the liquid to solid ratio 6:1 , the pyrite ball milling activation time 3h, copper precipitation rate was 11.6 % , Fe3 restore the rate of 76.4% . Sodium thiosulfate processing , high-speed rail biological heap leaching solution Cu2 7.41 g · L- 1 the TFe to 27.9g L -1 Fe3 14.68g · L-1 Shi , at a reaction temperature of 80 ° C , thio sodium sulfate and used in an amount of 18 g · L-1, the reaction time was 60 minutes under conditions of Fe3 reduction rate reached 99.68% , iron precipitation rate reached 17.52% , 99.96% of the copper precipitation rate . Thiosulfate processing obtained precipitate slag Cu , S , Fe mass percentage content of 46.61% , 27.85% , 3.23% , the main phase of CuS and S . The high the iron stack immersion residue treatment with sodium thiosulfate , added concentrated sulfuric acid and hydrogen peroxide at 50 ℃ , the dissolution of copper in the residue obtained copper sulfate solution, the copper recovery reached 93.1% . After evaporation and crystallization copper sulfate pentahydrate crystals , copper sulfate yield of 85.37% . Heap leaching solution with sodium thiosulfate processing high-speed rail biological treatment 10000 m3 monthly output of 232.5 tons of copper sulfate pentahydrate , direct profits of up to 843,000 yuan . Sodium thiosulfate after the sedimentation process XRL heap immersion Fe3 reduced into Fe2, to heap immersion acidity increases , the copper to be recovered , after treatment solution is returned to the heap leach effluent discharge, greatly reducing the savings of water and sulfuric acid required by the leaching , with good economic and social benefits .
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