Thermodynamic Analysis and Experimental Investigation of Al and F Removal from Sulfuric Acid Leachate of Spent LiFePO<sub>4</sub> Battery Powder
The co-precipitation thermodynamics of the Li<sup>+</sup>–Fe<sup>2+</sup>/Fe<sup>3+</sup>–Al<sup>3+</sup>–F<sup>−</sup>–SO<sub>4</sub><sup>2−</sup>–PO<sub>4</sub><sup>3−</sup>–H<sub>2<...
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2021-10-01
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| author | Yafei Jie Shenghai Yang Pengfei Shi Di Chang Gang Fang Caixuan Mo Jiang Ding Zhiqiang Liu Yanqing Lai Yongming Chen |
| author_facet | Yafei Jie Shenghai Yang Pengfei Shi Di Chang Gang Fang Caixuan Mo Jiang Ding Zhiqiang Liu Yanqing Lai Yongming Chen |
| author_sort | Yafei Jie |
| collection | DOAJ |
| description | The co-precipitation thermodynamics of the Li<sup>+</sup>–Fe<sup>2+</sup>/Fe<sup>3+</sup>–Al<sup>3+</sup>–F<sup>−</sup>–SO<sub>4</sub><sup>2−</sup>–PO<sub>4</sub><sup>3−</sup>–H<sub>2</sub>O system at 298 K is studied, aiming to understand the precipitation characteristics. Based on the principle of simultaneous equilibrium and the mass action law, the missing <i>Ksp</i> values of AlF<sub>3</sub> and FeF<sub>3</sub> were estimated. The results of thermodynamic calculation demonstrate that Al<sup>3+</sup> and F<sup>−</sup> in the sulfuric acid leachate could be preferentially precipitated in the form of AlPO<sub>4</sub> and FeF<sub>3</sub> by the precise adjustment of the final pH value. Only a small amount of P and Fe was lost by the precipitation of Fe<sub>3</sub>(PO<sub>4</sub>)<sub>2</sub>·8H<sub>2</sub>O, FePO<sub>4</sub>, and Fe(OH)<sub>3</sub> during the purification process. Controlling the oxidation of ferrous ions effectively is of critical significance for the loss reduction of P and Fe. Precipitation experiments at different pH value indicated that the concentration of Al<sup>3+</sup> and F<sup>−</sup> in the leachate decreased as the final pH value rose from 3.05 to 3.90. When the final pH value was around 3.75, aluminum and fluoride ion impurities could be deeply purified, and the loss rate of phosphate ions and iron ions could be reduced as much as possible. Relevant research results can provide theoretical guidance for the purification of leachate in the wet recycling process of lithium-ion batteries. |
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| last_indexed | 2024-03-10T06:23:36Z |
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| spelling | doaj.art-feeb5317256748918edbb1dcce1dc8bf2023-11-22T19:10:00ZengMDPI AGMetals2075-47012021-10-011110164110.3390/met11101641Thermodynamic Analysis and Experimental Investigation of Al and F Removal from Sulfuric Acid Leachate of Spent LiFePO<sub>4</sub> Battery PowderYafei Jie0Shenghai Yang1Pengfei Shi2Di Chang3Gang Fang4Caixuan Mo5Jiang Ding6Zhiqiang Liu7Yanqing Lai8Yongming Chen9School of Metallurgy and Environment, Central South University, Changsha 410083, ChinaSchool of Metallurgy and Environment, Central South University, Changsha 410083, ChinaSchool of Metallurgy and Environment, Central South University, Changsha 410083, ChinaSchool of Metallurgy and Environment, Central South University, Changsha 410083, ChinaSchool of Metallurgy and Environment, Central South University, Changsha 410083, ChinaSchool of Metallurgy and Environment, Central South University, Changsha 410083, ChinaSchool of Metallurgy and Environment, Central South University, Changsha 410083, ChinaInstitute of Rare Metals, Guangdong Academy of Science, Guangzhou 510651, ChinaSchool of Metallurgy and Environment, Central South University, Changsha 410083, ChinaSchool of Metallurgy and Environment, Central South University, Changsha 410083, ChinaThe co-precipitation thermodynamics of the Li<sup>+</sup>–Fe<sup>2+</sup>/Fe<sup>3+</sup>–Al<sup>3+</sup>–F<sup>−</sup>–SO<sub>4</sub><sup>2−</sup>–PO<sub>4</sub><sup>3−</sup>–H<sub>2</sub>O system at 298 K is studied, aiming to understand the precipitation characteristics. Based on the principle of simultaneous equilibrium and the mass action law, the missing <i>Ksp</i> values of AlF<sub>3</sub> and FeF<sub>3</sub> were estimated. The results of thermodynamic calculation demonstrate that Al<sup>3+</sup> and F<sup>−</sup> in the sulfuric acid leachate could be preferentially precipitated in the form of AlPO<sub>4</sub> and FeF<sub>3</sub> by the precise adjustment of the final pH value. Only a small amount of P and Fe was lost by the precipitation of Fe<sub>3</sub>(PO<sub>4</sub>)<sub>2</sub>·8H<sub>2</sub>O, FePO<sub>4</sub>, and Fe(OH)<sub>3</sub> during the purification process. Controlling the oxidation of ferrous ions effectively is of critical significance for the loss reduction of P and Fe. Precipitation experiments at different pH value indicated that the concentration of Al<sup>3+</sup> and F<sup>−</sup> in the leachate decreased as the final pH value rose from 3.05 to 3.90. When the final pH value was around 3.75, aluminum and fluoride ion impurities could be deeply purified, and the loss rate of phosphate ions and iron ions could be reduced as much as possible. Relevant research results can provide theoretical guidance for the purification of leachate in the wet recycling process of lithium-ion batteries.https://www.mdpi.com/2075-4701/11/10/1641spent LiFePO<sub>4</sub> batterysulfuric acid leachate purificationco-precipitation thermodynamicsaluminum precipitationfluorine removal |
| spellingShingle | Yafei Jie Shenghai Yang Pengfei Shi Di Chang Gang Fang Caixuan Mo Jiang Ding Zhiqiang Liu Yanqing Lai Yongming Chen Thermodynamic Analysis and Experimental Investigation of Al and F Removal from Sulfuric Acid Leachate of Spent LiFePO<sub>4</sub> Battery Powder Metals spent LiFePO<sub>4</sub> battery sulfuric acid leachate purification co-precipitation thermodynamics aluminum precipitation fluorine removal |
| title | Thermodynamic Analysis and Experimental Investigation of Al and F Removal from Sulfuric Acid Leachate of Spent LiFePO<sub>4</sub> Battery Powder |
| title_full | Thermodynamic Analysis and Experimental Investigation of Al and F Removal from Sulfuric Acid Leachate of Spent LiFePO<sub>4</sub> Battery Powder |
| title_fullStr | Thermodynamic Analysis and Experimental Investigation of Al and F Removal from Sulfuric Acid Leachate of Spent LiFePO<sub>4</sub> Battery Powder |
| title_full_unstemmed | Thermodynamic Analysis and Experimental Investigation of Al and F Removal from Sulfuric Acid Leachate of Spent LiFePO<sub>4</sub> Battery Powder |
| title_short | Thermodynamic Analysis and Experimental Investigation of Al and F Removal from Sulfuric Acid Leachate of Spent LiFePO<sub>4</sub> Battery Powder |
| title_sort | thermodynamic analysis and experimental investigation of al and f removal from sulfuric acid leachate of spent lifepo sub 4 sub battery powder |
| topic | spent LiFePO<sub>4</sub> battery sulfuric acid leachate purification co-precipitation thermodynamics aluminum precipitation fluorine removal |
| url | https://www.mdpi.com/2075-4701/11/10/1641 |
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