Laterite ore processing with hydrogen via mild chemical pressure leaching or bioleaching

Limonitic laterites consist of a high amount of iron oxides/hydroxides, such as goethite and hematite, being recalcitrant in hydrometallurgical processing for nickel and cobalt recovery. High pressure acid leaching (HPAL) is the currently most applied processing technology for limonitic laterites. Still, research is ongoing to develop technologies with less energy consumption and a lower carbon footprint. Among these, chemical leaching under mild conditions and bioleaching were investigated, as well as using hydrogen gas as a reductant. In this study, these approaches were combined. Bioleaching of laterite ore using hydrogen was shown for the first time, and anaerobic batch incubation with Acidithiobacillus ferrooxidans showed that bioleaching with hydrogen was as efficient in metal extraction as with addition of elemental sulfur. Chemical laterite leaching with hydrogen under pressure at 50 bar and ambient temperature also succeeded in metal extraction; however, the leaching efficiency strongly depended on the laterite mineralogical composition. • Bioleaching of laterite ore using hydrogen was shown for the first time. • Hydrogen was as efficient as elemental sulfur with Acidithiobacillus ferrooxidans. • Successful chemical laterite leaching with hydrogen at 50 bar and ambient temperature. • Leaching efficiency strongly depended on laterite mineralogical composition.