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The Chinese Journal of Process Engineering ›› 2023, Vol. 23 ›› Issue (12): 1676-1684.DOI: 10.12034/j.issn.1009-606X.223056

• Research Paper • Previous Articles     Next Articles

Study on performance and mechanism of replaced stripping of light rare earth by Ce(Ⅳ) in nitrate solution

Yi WANG1,2,  Jian LI2,3,  Mengling HUANG1,2,  Xuxia ZHANG2,3,  Hui ZHANG1,2,3,4*,  Tao QI1,2,3,4*   

  1. 1. School of Rare Earths, University of Science and Technology of China, Hefei, Anhui 230026, China 2. Ganjiang Innovation Academy, Chinese Academy of Sciences, Ganzhou, Jiangxi 341000, China 3. Jiangxi Province Key Laboratory of Cleaner Production of Rare Earths, Ganzhou, Jiangxi 341000, China 4. Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China
  • Received:2023-02-28 Revised:2023-05-18 Online:2023-12-28 Published:2024-01-01

P507硝酸体系Ce(IV)置换反萃轻稀土的性能及机理研究

王怡1,2， 李建2,3， 黄梦玲1,2， 张旭霞2,3， 张绘1,2,3,4*， 齐涛1,2,3,4*   

  1. 1. 中国科学技术大学稀土学院，安徽 合肥 230026 2. 中国科学院赣江创新研究院，江西 赣州 341000 3. 江西省稀土清洁生产重点实验室，江西 赣州 341000 4. 中国科学院过程工程研究所，北京 100190
  • 通讯作者: 张绘 zhanghv@ipe.ac.cn
  • 基金资助:
    中国科学院重点部署项目;中国科学院赣江创新研究院自主部署项目;江西省自然科学青年基金;中国科学院绿色制造创新研究院;赣州市重点研发计划一般项目;江西省稀土清洁生产重点实验室开放基金;江西省双千计划;国家自然科学基金;国家重点研发计划;中国科学院江西稀土研究所项目

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Abstract: The traditional solvent extraction leads to a large amount of acid-alkali consumption and saline wastewater discharge. Herein, a new strategy was proposed according to the different extraction ability of Ce(IV) and RE(III) with P507, driven by the oxidation and reduction of Ce. As one of the key procedure, the performance and mechanism of replaced stripping of light rare earth elements (LREEs) by Ce(IV) in nitrate solution was investigated in this study. Pr(III) was selected as the representative element of LREEs for the follow-up experiments. Several operational parameters such as phase ratio, temperature, reaction time, concentration of nitrate and Ce(IV) in aqueous feed, and acidity were investigated. Results indicated that the stripping efficiency of Pr(III) increased significantly with increasing temperature, reaction time and Ce(IV) concentration, while it decreased with the increase of phase ratio. The stripping efficiency of Pr(III) was 98% by 0.56 mol/L Ce(IV) under the optimal conditions, which was higher than that by 1 mol/L HCl solution. This method was generally applicable on the stripping of the other LREEs. The mechanism was explored by slope method and FT-IR spectrometric analysis. The solvation mechanism was carried out, and the key complexes in the organic phase before and after stripping were determined to be Pr(NO3)(HA2)2·(HA) and Ce(NO3)2A2, respectively. From the FT-IR spectrometric analysis, it can be concluded that the H in P-O-H was replaced by the rare earth, which was bonded with P=O. Nitrate was also involved in the reaction because of the presence of the characteristic peaks of nitrate.

Key words: Light rare earth elements, stripping, Ce(IV), P507, nitrate-acid

摘要： 传统溶剂萃取法具有酸碱消耗大、含盐废水排放量大的缺点。以Ce的氧化还原为驱动力，根据P507对Ce(IV)和RE(III)的萃取能力不同，提出了一种新的反萃方法。研究了Ce(IV)在硝酸溶液中置换反萃轻稀土的反萃条件及机理。以Pr(III)作为轻稀土的代表元素探究了反萃相比、温度、反应时间、溶液酸度及Ce(IV)浓度、硝酸根浓度等因素对轻稀土反萃率的影响。结果表明，随着反应温度、时间及硝酸高铈铵溶液浓度增加，Pr反萃率不断增加，随着相比增大反萃率降低，使用0.56 mol/L硝酸高铈铵溶液反萃负载Pr的有机相，优化条件下Pr反萃率达98%，优于1 mol/L盐酸，该方法对轻稀土均有较好的反萃率。通过斜率法推测了萃合物形式及反应机理，FT-IR进一步验证了该机理。该反应为溶剂化机理，反萃前后有机相中组成分别为Pr(NO3)(HA2)2·(HA)和Ce(NO3)2A2。从FT-IR光谱分析可知，稀土元素置换了P-O-H中的H，并与P=O键配位，有机相中[NO3-]O的特征峰进一步证明了[NO3-]O参与反应。

关键词: 轻稀土元素, 反萃, Ce(IV), P507, 硝酸