1. Extraction of Rare Earth Elements from the Phosphate Concentrate of Apatite Processing.
- Author
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Val'kov, A. V. and Mesyats, E. A.
- Subjects
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APATITE , *CERIUM group , *RARE earth metals , *TRIBUTYL phosphate , *PHOSPHATES , *ORGANIC acids , *NITRIC acid - Abstract
The industrially important rare-earth elements (REE) are contained in pronounced quantities (up to 1 wt %) in the apatite of the Kola Peninsula, which dictates interest in their extraction. The extraction of rare-earth elements with 100% tributyl phosphate from solutions obtained by dissolving the phosphate concentrate of REE isolated from the nitrogen phosphate solutions of apatite processing has been considered. It was found that to prevent precipitation, the extractant (100% tributyl phosphate) should be preliminarily saturated with nitric acid to a concentration C1 = (αC3–C2 + C4)/α, where C2, C3, and C4 are the nitric acid concentrations (mol/dm3) in the initial solution, saturated extract, and raffinate, respectively; α is the flow rate ratio of the organic and aqueous phases; and C1 is the minimum concentration of nitric acid in the fresh organic phase at which there is no precipitation of REE phosphates at the first stages along the course of the organic phase. A combined technology has been proposed, including the stage of REE extraction from a nitrogen phosphate solution, followed by the transfer of some part of the extract saturated with REE oxides to 150–160 g/dm3 as an initial solution for separation of REEs into groups (at the Pr–Nd or Nd–Sm boundary). The cerium group elements are concentrated in the raffinate of the separation cascade (wt %): La2O3 38.1, CeO2 61.2, Pr6O11 0.7; the didymium concentrate Pr6O11 + Nd2O3 is concentrated in the extract. [ABSTRACT FROM AUTHOR] more...
- Published
- 2023
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