In order to achieve deeper understanding of rare earth elements（REEs） behaviors during phosphate rock processing with H3PO4. The solubility of REEs in Ca（H2PO4）2-H3PO4 solutions with various concentrations of Ca（H2PO4）2 at different temperatures were tested. The results demonstrate that REEs solubility decreases sharply with the increasing concentration of Ca（H2PO4）2. Equations between [REE3+] and [H+],[H+] and [Ca2+] in Ca（H2PO4）2-H3PO4 solutions were built based on the precipitation-dissolution equilibrium of rare earth phosphates and the ionization equilibrium of H3PO4. According to the equations, the decreasing mechanism of REEs solubility caused by elevated concentration of Ca（H2PO4）2 was determined. The mechanism can be illustrated as that the elevated concentration of [H2PO4-] decreases the concentration of hydrogen ion by retarding the ionization process of H3PO4 and directly promotes the precipitation of rare earth phosphates. Furthermore, it can be easy deduced that similar effect would be caused by the other cation impurities(Fe3+, Al3+, etc.) on REEs solubility based on the mechanism. In addition, superimposed reduction effect on REEs solubility caused by the elevated concentration of Ca（H2PO4）2 and the elevated temperature is found. This superimposed effect leads to a super low solubility of REEs in Ca（H2PO4）2-H3PO4 solution. On the basis of the experimental study, outlooks and suggestions for further development of REEs recovery method are given.
类型: 期刊论文
作者: Shengxi Wu,Longsheng Zhao,Liangshi Wang,Xiaowei Huang,Yunhan Zhang,Zongyu Feng,Dali Cui
来源: Journal of Rare Earths 2019年05期
年度: 2019
分类: 工程科技Ⅰ辑
专业: 冶金工业
单位: National Engineering Research Center for Rare Earth Materials, General Research Institute for Nonferrous Metals,School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing (USTB)
基金: Project supported by National Natural Science Foundation of China(51674036),Beijing Nova Program(Z161100004916108)
分类号: TF845
页码: 520-527
总页数: 8
文件大小: 4078K
下载量: 13
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