Industrial & Engineering Chemistry Research, Vol.51, No.15, 5596-5607, 2012
Purification of Leachate from Simultaneous Leaching of Galena Concentrate and Pyrolusite and Preparation of PbSO4 and Mn3O4
This paper presents the results of investigation on simultaneous leaching of galena concentrate and pyrolusite in acid medium. It has been confirmed that the leached products as the raw materials-PbCl2, MnCl2 for the PbSO4 and Mn3O4 preparations could be obtained during the leaching processes. Special emphasizes are placed on the purification of the simultaneous leaching solution including removals of Fe2+, Pb2+, Zn2+, Ca2+, and preparations. The factors affecting the purification, such as pH, temperature, agitation rate, and dosages of Cl- and Na2S are investigated in leaching cells. The results show that, at appropriate conditions, iron is removed in the form of FeOOH, Pb2+ and Zn2+ are vulcanized by Na2S, and Ca2+ is removed in the form of CaF2 precipitation. After purification and crystallizing-out of PbCl2 (97.17%), the effects of pH, temperature, reaction time, concentration, stirring rate, and drying methods on preparations are examined. The mechanisms are addressed by theoretical calculations and experiments. The results indicate that the content of PbSO4 is 99.46% characterized by elemental analysis, XRD, and SEM. The purity of Mn3O4 is identified by TG-DSC, chemical analysis, and XRD, and the Mn in the Mn3O4 product accounts for 71.7%.