Production of lead concentrate from bioleached residue tailings by brine leaching followed by sulfide precipitation

Abstract

Abstract This study investigated a process for the production of lead (Pb) concentrates from bioleached residue by brine leaching, followed by sulfide precipitation of lead sulfides. Bioleached residue characterization indicated that the Pb was in the form of anglesite (PbSO4). The bioleached residue was extracted by leaching it in a sodium chloride (NaCl) solution at room temperature for 200 r/min. This effectively extracted Pb. More than 84% of the lead was extracted from the bioleaching residues at a NaCl concentration of 150 g/dm3. Pb concentrate was quantitatively produced from the brine leaching solution by adding sodium sulfide as a precipitant. The optimum conditions for Pb precipitation were: 0.6 g/dm3 sodium sulfide (Na2S); and 10 min leaching time in the solution. X-ray diffractometer (XRD) or scanning electron microscopy (SEM) analysis was used characterize the raw materials, brine leached residues, and precipitation. The study also investigated the mechanism involved in brine leaching and precipitation of Pb from the bioleached residue. Finally, a scale-up experiment found that total Pb extraction exceeded 88%, and the quality of the Pb concentrate could meet industrial requirements for roasting processes. This process provides an eco-friendly and economic alternative for treating solid waste containing PbSO4.