A review of mechanism and technology of vanadium extraction from strategic mineral black shale

Black shale represents a unique and strategic vanadium resource in China, accounting for ~ 90% of the nation’s vanadium reserves. The complex forms of occurrence of vanadium in black shale, particularly its incorporation into aluminosilicate mica via isomorphism, render it tightly bound and challenging to extract. Against the backdrop of green metallurgy and the “Double Carbon” initiative, methodologies such as the new roasting process, the whole hydrometallurgical process, and biological leaching have been developed, with their mechanisms thoroughly examined. This review examines the mechanisms of each process, highlighting that enhanced vanadium leaching is primarily achieved by disrupting the covalent bonds in vanadium-containing mica or by oxidizing lower-valence vanadium. However, the leaching mechanism of autotrophic microorganisms for black shale remains unclear. Drawing from various studies, a mechanism involving the cooperative action of iron-oxidizing and sulfur-oxidizing bacteria in the leaching of black shale is proposed. A comparative analysis of these enhancement processes reveals that microbial technology offers benefits such as environmental sustainability, low carbon footprint, minimal pollution, and scalability, marking it a promising area for research and application. However, the technological processes and mechanisms underlying microbial leaching of black shale require further elucidation. Future studies should focus on developing highly efficient leaching bacteria, exploring the synergistic effects between microorganisms and examining the mechanisms of biological leaching to provide technical and theoretical foundations for efficient and eco-friendly microbial extraction of vanadium from black shale.

Graphic abstract