Purification of Leachate from Simultaneous Leaching of Galena Concentrate and Pyrolusite and Preparation of PbSO₄ and Mn₃O₄

Abstract

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PbCl 2 , MnCl 2 for the PbSO 4 and Mn 3 O 4 preparations could be obtained during the leaching processes. Special emphasizes are placed on the purification of the simultaneous leaching solution including removals of Fe 2+ , Pb 2+ , Zn 2+ , Ca 2+ , and preparations. The factors affecting the purification, such as pH, temperature, agitation rate, and dosages of Cl − and Na 2 S are investigated in leaching cells. The results show that, at appropriate conditions, iron is removed in the form of FeOOH, Pb 2+ and Zn 2+ are vulcanized by Na 2 S, and Ca 2+ is removed in the form of CaF 2 precipitation. After purification and crystallizing-out of PbCl 2 (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 PbSO 4 is 99.46% characterized by elemental analysis, XRD, and SEM. The purity of Mn 3 O 4 is identified by TG-DSC, chemical analysis, and XRD, and the Mn in the Mn 3 O 4 product accounts for 71.7%.

Dissolution Kinetics of Cerussite in Acidic Sodium Chloride Solutions

“…Various leaching agents, such as acids, sodium hydroxide, and chloride solutions, are used in the hydrometallurgical process of lead. [10][11][12][13][14] An acidic medium, such as hydrochloric, sulfuric, nitric, fluoboric, fluosilicic, or other organic acid, cannot serve as the leaching agent for extracting lead from materials because of their low boiling temperatures, high corrosion, low solubility, easy decompositions, and hydrolysis. 15,16 Furthermore, lead dissolves along with many other metals such as Fe, Ca, and Mg, resulting in high acid consumption and complex purification process.…”

“…in the leachate through various methods, such as cementation, electrowinning, ion exchange, and crystallization of PbC1 2 by cooling the leachate. 14,26 Most studies [27][28][29] have shown that the solubility of lead-bearing materials in chloride systems increases with an increase in temperature and the chloride ion concentration. At lower concentration of chloride ions, the precipitation of PbCl 2 would occur, decreasing the lead leaching fraction.…”