Rare Earth Metal Ion-Associates in Ln<sup>3+</sup>—CO<sub>3</sub><sup>2−</sup>—H<sub>2</sub>O System
This study focused on the nature of rare earth metal complex compounds that can form during the carbonate–alkaline processing of industrial waste materials, such as phosphogypsum and red mud, at 70–100 °C and 1–10 atm. Experimental findings revealed that the dissolution of synthetic carbonates of ra...
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2025-02-01
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| author | Tatiana Litvinova Stepan Gerasev Vasiliy Sergeev Egor Lidanovskiy |
| author_facet | Tatiana Litvinova Stepan Gerasev Vasiliy Sergeev Egor Lidanovskiy |
| author_sort | Tatiana Litvinova |
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| description | This study focused on the nature of rare earth metal complex compounds that can form during the carbonate–alkaline processing of industrial waste materials, such as phosphogypsum and red mud, at 70–100 °C and 1–10 atm. Experimental findings revealed that the dissolution of synthetic carbonates of rare earth elements (REEs) in a concentrated carbonate-ion medium (3 mol/L) leads to the formation of ion-associates of varying strengths. Light (lanthanum, praseodymium, and neodymium) and medium (samarium) REE groups exhibited a tendency to form loose ion-associates, whereas heavy REEs (terbium, dysprosium, holmium, erbium, thulium, lutetium, and yttrium) formed close ion-associates. To confirm the existence of these ion-associates, the specific conductivity of solutions was measured after dissolving thulium (III) and samarium (III) carbonates at phase ratios ranging from 1:2000 g/mL to 1:40 g/mL in a potassium carbonate medium. The decay of ion-associates, leading to the precipitation of rare earth metal (III) carbonates, was tested in an ammonium carbonate medium. Thermal decomposition of ammonium carbonate at 70–75 °C during 1–4 h was accompanied by full rare earth carbonates’ sedimentation and its in-the-way separation into groups because of the varied strength of ion-associates. The results of this study provide a basis for developing processes to separate rare earth metals into groups during their carbonate–alkaline extraction into solution. |
| format | Article |
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| institution | OA Journals |
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| language | English |
| publishDate | 2025-02-01 |
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| spelling | doaj-art-7093ce8c960c4851a27a60f00a05bf672025-08-20T02:10:23ZengMDPI AGMetals2075-47012025-02-0115323910.3390/met15030239Rare Earth Metal Ion-Associates in Ln<sup>3+</sup>—CO<sub>3</sub><sup>2−</sup>—H<sub>2</sub>O SystemTatiana Litvinova0Stepan Gerasev1Vasiliy Sergeev2Egor Lidanovskiy3The Department of General and Physical Chemistry, Empress Catherine II Saint Petersburg Mining University, 199106 Saint Petersburg, RussiaThe Metallurgy Department, Empress Catherine II Saint Petersburg Mining University, 199106 Saint Petersburg, RussiaThe Department of General and Physical Chemistry, Empress Catherine II Saint Petersburg Mining University, 199106 Saint Petersburg, RussiaThe Department of Chemical Engineering and Energy Processing, Empress Catherine II Saint Petersburg Mining University, 199106 Saint Petersburg, RussiaThis study focused on the nature of rare earth metal complex compounds that can form during the carbonate–alkaline processing of industrial waste materials, such as phosphogypsum and red mud, at 70–100 °C and 1–10 atm. Experimental findings revealed that the dissolution of synthetic carbonates of rare earth elements (REEs) in a concentrated carbonate-ion medium (3 mol/L) leads to the formation of ion-associates of varying strengths. Light (lanthanum, praseodymium, and neodymium) and medium (samarium) REE groups exhibited a tendency to form loose ion-associates, whereas heavy REEs (terbium, dysprosium, holmium, erbium, thulium, lutetium, and yttrium) formed close ion-associates. To confirm the existence of these ion-associates, the specific conductivity of solutions was measured after dissolving thulium (III) and samarium (III) carbonates at phase ratios ranging from 1:2000 g/mL to 1:40 g/mL in a potassium carbonate medium. The decay of ion-associates, leading to the precipitation of rare earth metal (III) carbonates, was tested in an ammonium carbonate medium. Thermal decomposition of ammonium carbonate at 70–75 °C during 1–4 h was accompanied by full rare earth carbonates’ sedimentation and its in-the-way separation into groups because of the varied strength of ion-associates. The results of this study provide a basis for developing processes to separate rare earth metals into groups during their carbonate–alkaline extraction into solution.https://www.mdpi.com/2075-4701/15/3/239rare earth metalslanthanidesion-associatescarbonate complexesrare earth carbonatessolubility |
| spellingShingle | Tatiana Litvinova Stepan Gerasev Vasiliy Sergeev Egor Lidanovskiy Rare Earth Metal Ion-Associates in Ln<sup>3+</sup>—CO<sub>3</sub><sup>2−</sup>—H<sub>2</sub>O System Metals rare earth metals lanthanides ion-associates carbonate complexes rare earth carbonates solubility |
| title | Rare Earth Metal Ion-Associates in Ln<sup>3+</sup>—CO<sub>3</sub><sup>2−</sup>—H<sub>2</sub>O System |
| title_full | Rare Earth Metal Ion-Associates in Ln<sup>3+</sup>—CO<sub>3</sub><sup>2−</sup>—H<sub>2</sub>O System |
| title_fullStr | Rare Earth Metal Ion-Associates in Ln<sup>3+</sup>—CO<sub>3</sub><sup>2−</sup>—H<sub>2</sub>O System |
| title_full_unstemmed | Rare Earth Metal Ion-Associates in Ln<sup>3+</sup>—CO<sub>3</sub><sup>2−</sup>—H<sub>2</sub>O System |
| title_short | Rare Earth Metal Ion-Associates in Ln<sup>3+</sup>—CO<sub>3</sub><sup>2−</sup>—H<sub>2</sub>O System |
| title_sort | rare earth metal ion associates in ln sup 3 sup co sub 3 sub sup 2 sup h sub 2 sub o system |
| topic | rare earth metals lanthanides ion-associates carbonate complexes rare earth carbonates solubility |
| url | https://www.mdpi.com/2075-4701/15/3/239 |
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