Ferric methanesulfonate as an effective and environmentally sustainable lixiviant for Zn extraction from sphalerite (ZnS)

Zinc is currently extracted from sphalerite (ZnS) by either sintering-smelting or roasting-leaching. These high-temperature processes produce environmentally hazardous sulfur dioxide gas. Hence, sustainable zinc extraction calls for direct leaching at low temperatures. Here, we show that ferric methanesulfonate a high performing lixiviant this purpose. Using 0.8 M methanesulfonate, 99.3% Zn was 106−150 μm particles after 70 °C 96 h. Elemental sulfur, rather than dioxide, produced as by-product. When compared to common inorganic lixiviants such sulfate chloride, demonstrates greater efficiency and less corrosive, toxic, does not release harmful gases. Mineralogical, microscopical, compositional characterization of reaction products confirmed the formation core–shell structure consisting core shell, manifestation coupled dissolution-reprecipitation mineral replacement mechanism. Efficient facilitated interconnected pores in which provided pathways mass transfer between core. The precipitation anglesite (PbSO4), some instances caused surface passivation through infilling shells, suggests Pb2+ concentration should be controlled when applying extraction.