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Title: Bioleaching of rare earth elements from waste phosphors and cracking catalysts

Four microbial cultures were evaluated for organic acid production and their potential utility for leaching of rare earth elements (REE) from retorted phosphor powder (RPP) and spent fluidized cracking catalyst (FCC). Three of the cultures (2 bacterial, 1 fungal) were isolated from environmental and industrial materials known to contain rare earth elements. The other was the well-known and industrially important bacterium Gluconobacter oxydans. Gluconic acid was the predominant identified organic acid produced by all of the cultures; citric and acetic acid were among the other acids detected. There was also maximum REE leaching by cell free culture supernatants obtained with Gluconobacter and the FCC; 49% of total REE was recovered, with preferential recovery of lanthanum over cerium. The phosphor powder was more difficult to leach; only ~2 % total REE was leached from RPP with Gluconobacter. Tests with the RPP indicated that the extent of REE solubilization was similar whether whole cell cultures or cell-free supernatants were used. However, Gluconobacter cell-free culture supernatants with 10-15 mM gluconic acid outperformed abiotically prepared leaching solutions with 30 mM gluconic acid concentrations. Abiotic tests showed that increasing gluconic acid concentrations increased leaching efficiency; for example, total REE leaching from FCC increased from 24more » to 36 to 45% when gluconic acid was increased from 10 to 30 to 90 mM. Our research shows that utilizing microorganisms that produce gluconic acid can result in effective leaching of REE from waste materials, and optimizing gluconic acid production will improve recovery.« less
 [1] ;  [1] ;  [1] ;  [2] ;  [1]
  1. Idaho National Lab. (INL), Idaho Falls, ID (United States). Biological and Chemical Processing Dept.
  2. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). Biosciences and Biotechnology Division
Publication Date:
Report Number(s):
Journal ID: ISSN 0304-386X; PII: S0304386X16305473
Grant/Contract Number:
AC07-05ID14517; AC52-07NA27344
Accepted Manuscript
Journal Name:
Additional Journal Information:
Journal Volume: 166; Journal Issue: C; Journal ID: ISSN 0304-386X
Research Org:
Idaho National Lab. (INL), Idaho Falls, ID (United States)
Sponsoring Org:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Advanced Manufacturing Office (EE-5A)
Country of Publication:
United States
60 APPLIED LIFE SCIENCES; 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; heterotrophic bioleaching; urban biomining; rare earth elements; gluconic acid; retorted phosphor powders; fluid catalytic cracking catalyst
OSTI Identifier:
Alternate Identifier(s):
OSTI ID: 1359167