Impacts of Phosphorous Source on Organic Acid Production and Heterotrophic Bioleaching of Rare Earth Elements and Base Metals from Spent Nickel-Metal-Hydride Batteries

• DOI: 10.1007/s12649-021-01398-x
• Publication Date: 2021-03-01T12:04:22Z
• Authors: Payam Rasoulnia; Robert Barthen; Kati Valtonen; Aino-Maija Lakaniemi
• Keywords: Base metal; Gluconic acid

Abstract This study investigated heterotrophic bioleaching of rare earth elements (REEs) and base metals from spent nickel-metal-hydride (NiMH) batteries. Furthermore, the impacts phosphorous source [Ca 3 (PO 4 ) 2 , KH PO K HPO ] its concentration on organic acid production by Gluconobacter oxydans Streptomyces pilosus were evaluated. Phosphorous affected microbial metal leaching. Among studied sources, use resulted in highest both bacteria. Increasing 2.7 to 27 mM enhanced pyruvic S. 2.2 10.7 mM. However, no was leached NiMH batteries with using either one-step, two-step or spent-medium bioleaching. With G. gluconic 45.0 produced at lowest When higher leaching efficiencies obtained for (88.0% vs. 68.0% Fe, 41.5% 35.5% Co, 18.5% vs 16.5% Ni), while more REEs (9.0% 6.0% total REEs). methods, faster than that REEs. Surplus should be avoided cultures as precipitation especially is possible. Graphic