Use of Phosphate Solubilizing Bacteria to Leach Rare Earth Elements from Monazite-Bearing Ore

Minerals

Doyun Shin¹  Jiwoong Kim¹  Byung-su Kim¹  Jinki Jeong¹  Jae-chun Lee¹ 

[1]Mineral Resources Resource Division, Korea Institute of Geoscience and Mineral Resources (KIGAM), Gwahangno 124, Yuseong-gu, Daejeon 305-350, Korea

[2] E-Mails:

关键词: bioleaching;    monazite;    phosphate solubilizing bacteria;    rare earth element;   

DOI  :  10.3390/min5020189

来源: mdpi

【 摘 要 】

In the present study, the feasibility to use phosphate solubilizing bacteria (PSB) to develop a biological leaching process of rare earth elements (REE) from monazite-bearing ore was determined. To predict the REE leaching capacity of bacteria, the phosphate solubilizing abilities of 10 species of PSB were determined by halo zone formation on Reyes minimal agar media supplemented with bromo cresol green together with a phosphate solubilization test in Reyes minimal liquid media as the screening studies. Calcium phosphate was used as a model mineral phosphate. Among the test PSB strains, Pseudomonas fluorescens, P. putida, P. rhizosphaerae, Mesorhizobium ciceri, Bacillus megaterium, and Acetobacter aceti formed halo zones, with the zone of A. aceti being the widest. In the phosphate solubilization test in liquid media, Azospirillum lipoferum, P. rhizosphaerae, B. megaterium, and A. aceti caused the leaching of 6.4%, 6.9%, 7.5%, and 32.5% of calcium, respectively. When PSB were used to leach REE from monazite-bearing ore, ~5.7 mg/L of cerium (0.13% of leaching efficiency) and ~2.8 mg/L of lanthanum (0.11%) were leached by A. aceti, and Azospirillum brasilense, A. lipoferum, P. rhizosphaerae and M. ciceri leached 0.5–1 mg/L of both cerium and lanthanum (0.005%–0.01%), as measured by concentrations in the leaching liquor. These results indicate that determination of halo zone formation was found as a useful method to select high-capacity bacteria in REE leaching. However, as the leaching efficiency determined in our experiments was low, even in the presence of A. aceti, further studies are now underway to enhance leaching efficiency by selecting other microorganisms based on halo zone formation.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.