Recovery of Metals from Leach Liquors: Biosorption versus Metal Sulfide Precipitation

Abstract

Extraction of metals (leaching) is chemical or biochemical processes that utilize acids or microorganisms to enhance the suspension of metals from the primary and secondary sources by making them more amenable to dissolution in aqueous solutions (leachate). Recovery of metals from the leachates is an essential stage supported by additional purification processes such as precipitation of impurities, electrowinning, solvent extraction, chemical or biological adsorption, and ion exchange. In this study, especially biosorption and metal sulfide precipitation are overviewed and discussed. Biosorption is a process by which particular biomass such as bacteria, fungi, yeast, agricultural wastes, algae, and biowastes can able to bind with specific ions or other molecules from aqueous solutions. Metal sulfide precipitation can be highly effective in obtaining a high degree of separation of metal cations from complex leachates. Each of these techniques has advantages and drawbacks. Sometimes, a technique may not be effective in attaining higher metal recovery. Therefore, different recovery techniques are needed to recover the target elements from the complex leachates. Maybe a combination of two or three recovery techniques is required to recover metals from complex leachates. Additionally, the research activity highlighted that metal sulfide precipitation and biosorption processes have to limit factors that could hinder the process scale-up. Thus, more research is needed to evaluate the environmental impacts of metal recovery from leach liquors. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2024.