Extraction of rare earth elements from upgraded phosphate flotation tailings
Phosphate rock contains traces of rare earth elements (REEs) and can be a secondary source of these critical materials as large tonnages of phosphate rock are mined annually. Attention has mostly focused on the extraction of REEs from phosphogypsum, which contains more than 70 percent of the REEs reporting to phosphate concentrate, with only limited work conducted on REE extraction from sand tailings and slime even though they account for 16 percent and 15 percent, respectively, of REEs mined with phosphate matrix.
In this work, phosphate flotation tailings were upgraded by gravity separation and froth flotation. Gravity separation was conducted using a laboratory shaking table, while flotation was conducted in a Denver D-12 flotation cell. The concentrated tailings were then leached by nitric acid followed by REE extraction with solvent and ion-exchange resin.
The sand tailings were assayed as having 2.6 percent phosphate (P2O5) and 198.1 µg/g REEs. It was found that the shaking table could produce tailing concentrate assayed as having 8.6 percent P2O5 and 616 µg/g REEs but with only 20 percent REE recovery, while the froth flotation produced froth concentrate assayed as having 8.1 percent P2O5 and 368.2 µg/g REEs with 63.5 percent REE recovery. Leaching the flotation concentrate with 5.2 M (25 percent) nitric acid followed by extraction with solvent and ion-exchange resin yielded precipitates with REE contents of 0.926 and 0.314 percent, respectively, compared with 0.716 and 0.213 percent when table concentrate was used.
Key wordsGravity separation Ion-exchange resin Solvent extraction Rare earth elements Flotation tailings
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- Becker, P., 1987, Phosphates and Phosphoric Acid: Raw Materials, Technology, and Economics of the Wet Process, 2nd edition, Marcel Dekker Inc., New York, NY.Google Scholar
- Chung, D., Kim, E., Lee, E., and Yoo, L., 1998, “Solubility of rare earth oxalate in oxalic and nitric acid media,” Journal of Industrial Engineering Chemistry, Vol. 4, No. 4, pp. 277–284.Google Scholar
- Guan, C., 2009, “Theoretical background of the Crago phosphate flotation process,” Minerals & Metallurgical Processing, Vol. 26, No. 2, pp. 55–64.Google Scholar
- Habashi, F., 1985, “The recovery of the lanthanides from phosphate rock,” Journal of Chemical Technology and Biotechnology, Vol. 35(A), pp. 5–14.Google Scholar
- Jorjani, E., Bagherieh, A., Mesroghli, Sh., and Chehreh Chelgani, S., 2008, “Prediction of yttrium, lanthanum, cerium and neodymium leaching recovery from apatite concentrate using artificial neural networks,” Journal of University of Science and Technology Beijing, Vol. 15, No. 4, pp.367–374.CrossRefGoogle Scholar
- Lambert, J., and Tognet, J., 1987, “Essentially Complete Recovery of Uranium, Yttrium, and Thorium, and Rare Earth Values from Phosphate Rock during Wet Process Production of Phosphoric Acid,” U.S. Patent 4636369.Google Scholar
- Lin, C.L., Hsieh, Ching-Hao, and Miller, J.D., 2013, “Characterization of rare-earth resources at Mountain Pass, CA, using high-resolution X-ray microtomography (HRXMT),” Minerals & Metallurgical Processing, Vol. 30, No. 1, pp. 10–17.Google Scholar
- Pradip, and Fuerstenau, D.W., 2013, “Design and development of novel flotation reagents for the beneficiation of Mountain Pass rare-earth ore,” Minerals & Metallurgical Processing, Vol. 30, No. 1, pp. 1–9.Google Scholar
- Zhang, X., Xiao, W., and Zhang, P., 2015, “Enrichment of Rare Earth Elements from Phosphate Flotation Tailings,” Beneficiation of Phosphate VII, March 29-April 3, Melbourne, Australia.Google Scholar