Hot Filtration:A Way to Enhance the Recovery of Chromite in Sulfuric Acid Leaching,with or without the Addition of Perchloric Acid

摘要

A high grade chromite concentrate obtained from the Pmarbasi region of Kayseri province in Turkey was reacted with a solution of sulfuric acid and perchloric acid at atmospheric pressure.The effects of temperature,duration,sulfuric acid concentration and perchloric acid addition on leach recovery were determined in several experiments.Hexavalent chromium contents of the final solutions were also analyzed after the experiments and it was found that at the end of leach reaction chromium appeared in the solution as Cr3+and it did not change into environmentally hazardous Cr6+.The final product in the solution was chromium(III) sulfate obtained with about 98.7% maximum recovery,under the optimum leaching conditions of 175 °C,2 h,84.6 wt % H2SO4 and 1/2 perchloric acid/chromite ratio.