Study On Zinc Hydrometallurgy "Two-phase Jarosite Precipitation-Pb And Ag Enrichment From The Leached Residues" Process

With regarding to the properties of high iron zinc concentrate, the technology of having iron prematured was adopted to meet the requirement of iron concentration after the jarosite had been precipitated, The advantages and limits of which were further analyzed and then a new techology named as’two-phase jarosite precipitation-Pb and Ag enrichment from the leached residues’was proposed to fully resolve the removal of iron in solution and develop the technology of Pb and Ag enrichment from leached residues. Then, the principles and facts of the processes involved were analyzed to get their optimized conditions. The optimized condition for leaching at neutral environment was as following: An initial20-60g/L H2SO4was added to reach pH5.1-5.4, reaction temperature was in the range from65℃to85℃, the duration of reaction time was in the range from1.5to2h, and the liquid to solid ration was in the range of7-9:1; The optimized condition for leaching at low acid concentration was as following:Final acid concentration15-25g/L, reaction temperature60℃-70℃, and the reaction time1.5h-2h; The optimized condition for leaching at high acid concentration was as following:Final acid concentration100g/L, reaction temperature90℃ ～95℃, and duration time2.5-3.5h; The condition for the first phase of jarosite precipitation was as following:initial acid15g/L, reaction temperature90℃, duration time1～1.5h; The condition for the first phase of jarosit precipitation was as following:initial iron content20-25g/L, Initial acid concentration18-25g/L, reaction temperature≥95℃, and the duration time≥3h. Results of pilot-scale experiments indicates that iron concentration after jarosite precipitation was less than4.5g/L, Ag content in leached residue was over600g/t, Pb content was over20%, and the zinc recover was more than97%。...