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Effects of contaminant metal ions on precipitation recovery of rare earth elements using oxalic acid
- Source :
- Journal of Rare Earths. 40:482-490
- Publication Year :
- 2022
- Publisher :
- Elsevier BV, 2022.
-
Abstract
- Solution equilibrium calculations were performed in this study to understand the impact of contaminant metal ions on the precipitation efficiency of selected rare earth elements (Ce3+, Nd3+, and Y3+) using oxalic acid as a precipitant. Trivalent metal ions, Al3+ and Fe3+, were found to considerably affect the precipitation efficiency of REEs. When Al3+ and Fe3+ concentrations were increased by 1 × 10−4 mol/L, in order to achieve an acceptable cerium recovery of 93% from solutions containing 1 × 10−4 mol/L Ce3+, oxalate dosage needed to increase by 1.2 × 10−4 and 1.68 × 10−4 mol/L, respectively. Such great impacts on the required oxalate dosage were also observed for Nd3+ and Y3+, which indicates that oxalic acid consumption and cost will be largely increased when the trivalent metal ions exist in REE-concentrated solutions. Effects of the divalent metal ions on the oxalate dosage is minimal. Furthermore, solution equilibrium calculation results showed that the precipitation of Fe3+ and Ca2+ (e.g., hematite and Ca(C2O4)∙H2O(s)) likely occurs during the oxalate precipitation of REEs at relatively high pH (e.g., pH 2.5), which will reduce rare earth oxalate product purity. In addition to the metal ions, anionic species, especially SO42−, were also found to negatively affect the precipitation recovery of REEs. For example, when 0.1 mol/L SO42− occurs in a solution containing 1 × 10−4 mol/L Ce3+ and 4 × 10−4 mol/L oxalate, the pH needed to be elevated from 2.0 to 3.3 to achieve the acceptable recovery. Overall, findings from this study provide guidance for the obtainment of high-purity rare earth products from solutions containing a considerable amount of contaminant metal ions by means of oxalic acid precipitation. Accepted version
- Subjects :
- Precipitation (chemistry)
Metal ions in aqueous solution
Rare earth
Oxalic acid
Inorganic chemistry
chemistry.chemical_element
0914 Resources Engineering and Extractive Metallurgy
02 engineering and technology
General Chemistry
Hematite
010402 general chemistry
021001 nanoscience & nanotechnology
01 natural sciences
Oxalate
0104 chemical sciences
chemistry.chemical_compound
Cerium
chemistry
Geochemistry and Petrology
visual_art
Mole
visual_art.visual_art_medium
0210 nano-technology
Materials
Subjects
Details
- ISSN :
- 10020721
- Volume :
- 40
- Database :
- OpenAIRE
- Journal :
- Journal of Rare Earths
- Accession number :
- edsair.doi.dedup.....fcccbeb1ffc614101f222e321a041843