Pressure Acid Leaching Method Of Dealing With The Trials Of High Indium Iron Zinc Sulfide Concentrates

Zinc and indium are one of the important nonferrous metals, China is rich of zinc resource, most of which exist in forms of sphalerite of high iron and high indium especially in Yunnan. The zinc smelt researchers have been studying a series technology on sphalerite of high iron for long time, but they just took into account recovery of zinc in those researches, they didn't research recovery of indium. Therefore, we carried out the experimental study on dealing with zinc sulfides concentrate bearing high content of indium and iron by acid leaching under oxygen pressure. This technology has the advantages of short flow, low-energy consumption, low-pollution, high metal recovery and comprehensive recovery of zinc and indium and so on, and sulfur in concentrate can be recovered as elemental sulfur.In order to obtain high leaching rate of zinc, indium, copper, cadmium and low leaching rate of iron after zinc sulfides concentrates bearing high content of indium and iron are dealing by acid leaching under oxygen pressure, this paper puts forward one-stage and two-stage leaching technologies of acid leaching under oxygen pressure to dealing with zinc sulfides concentrate bearing high content of indium and iron by experimental study on the basis of the analysis of thermodynamics and kinetics of zinc sulfides concentrate, and discusses the effects of every factor on acid leaching under oxygen pressure, finally obtain optimal leaching conditions. The material conditions are particularized at foot:(1) The optimal leaching conditions of one-stage leaching under oxygen pressure: liquid to solid ratio is 5.5: 1, leaching temperature is 145¹55℃, oxygen pressure is 1.4MPa, leaching time is 90min, stirring rev is 750r/ min(linear velocity is 94m/min), mol ratio of H₂SO₄: Zn is 1.2: 1, the dosage of surface active material(sodium lignosulfonates) is 0.1% of zinc sulfides concentrates, granularity of concentrate is more than 99.70% of -320 screen mesh. Leaching zinc sulfides concentrates bearing high content of indium and iron in these conditions, every metal leaching rate is:Zn>99°/c^ Cu⁸8%> Cd>97%, In>90%^ Fe²3%, and elemental sulfur transformation ratio is about 80%.(2) The optimal leaching conditions of two-stage leaching under oxygen pressure: liquid to solid ratio is 6.0: 1, leaching temperature is 145¹551C, oxygen pressure is 1.4MPa, stirring rev is 750r/ min(linear velocity is 94m/min), the dosage of surface active material(sodium lignosulfonates) is 0.1% of zinc sulfides concentrates, granularity of concentrate is more than 99.70% of —320 screen mesh, mol ratio of H2SO4: Zn of first stage is about 0.45: 1, leaching time of first stage is 50min, leaching time of second stage is 50min, the total dosage of H2SO4 is 51 53mL per lOOg concentrates. Leaching zinc sulfides concentrates bearing high content of indium and iron in these conditions, every metal leaching rate is: Zn>99^ Cd>99N In⁹4^ Cu⁹0> Fe²5, and elemental sulfur transformation ratio is about 75%.All these study results and experimental data can provide theoretical foundation and experiment guarantee on the industrialization of the technology of disposing zinc sulfides concentrate bearing high content of indium and iron by leaching under oxygen pressure.