Extracellular Precipitation for Critical Raw Materials Recovery

Europe is confronted with an increasing supply risk of critical raw materials (CRMs). CRMs can be defined as materials of which the risks of supply shortage and their impacts on the economy are higher compared to most of other raw materials. The European Commission has created the three lists of critical raw materials for the EU (in 2011, 2014 and 2017). To tackle the supply risk challenge, innovation is required with respect to sustainable primary mining, substitution of critical metals, and urban mining. In these three categories, bio-hydrometallurgy can play a crucial role. The natural biogeochemical cycles of elements under the microorganisms influence are the base of the bio-hydrometallurgical methods. Indeed, microbe-metal interactions have been successfully applied on full scale to win materials from primary sources, but are not sufficiently explored for metal recovery or recycling. Bio-hydrometallurgy is the advanced technology of the mineral raw recovery and processing as well as the environmental protection. This paper focuses on one of the basic processes of bio-hydrometallurgy - the extracellular precipitation of metals with biogenic compounds.