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<p>The presence of complex impurities in ion-adsorbed rare earth concentrates poses a significant challenge to producing high-purity leachates for downstream processing. This study introduces an effective activation pretreatment to enhance the leaching selectivity of a low-fluorine rare earth oxide concentrate (DF-1). The key innovation lies in transforming stable rare earth oxides into a rare earth hydroxychloride phase (RE(OH)ₓCl₃₋ₓ) with a more open structure and lower bond energy. This transformation enables highly selective dissolution of rare earth elements (REEs) over non-rare earth impurities (Al, Fe, Th, U, F) during subsequent pH-controlled acid leaching, by leveraging differences in their hydrolysis pH. Under optimized conditions (20 vol% activator, 80&#xa0;°C, 60&#xa0;min activation, leaching endpoint pH 2.4), the process achieved an exceptional REE leaching efficiency of 99.6%, while effectively suppressing the co-dissolution of impurities to remarkably low levels (1.13% for Al, 0.65% for Fe, 2.70% for Th, 10.5% for U, and 1.82% for F). However, the process efficacy was significantly compromised when applied to a high-fluorine concentrate (GF-1), attributed to the competitive formation of insoluble rare earth fluorides. This work presents a promising and selective hydrometallurgical strategy for treating low-fluorine rare earth concentrates, offering substantial potential for reducing environmental impact and operational costs.</p>

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Enhanced Acid Leaching of Low-Fluorine Rare Earth Oxide Concentrate Via an Activation Pretreatment

  • 期刊论文

  • 发表日期：

    2026年2月7日

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  • Di Wu,
  • Qiaofa Lan,
  • Xinjin Xiao,
  • An Guo,
  • Liusheng Ge,
  • Xiaoqiang Wen,
  • Sheng Zhong,
  • Lingdong Sun,
  • Chunsheng Liao

摘要

The presence of complex impurities in ion-adsorbed rare earth concentrates poses a significant challenge to producing high-purity leachates for downstream processing. This study introduces an effective activation pretreatment to enhance the leaching selectivity of a low-fluorine rare earth oxide concentrate (DF-1). The key innovation lies in transforming stable rare earth oxides into a rare earth hydroxychloride phase (RE(OH)ₓCl₃₋ₓ) with a more open structure and lower bond energy. This transformation enables highly selective dissolution of rare earth elements (REEs) over non-rare earth impurities (Al, Fe, Th, U, F) during subsequent pH-controlled acid leaching, by leveraging differences in their hydrolysis pH. Under optimized conditions (20 vol% activator, 80 °C, 60 min activation, leaching endpoint pH 2.4), the process achieved an exceptional REE leaching efficiency of 99.6%, while effectively suppressing the co-dissolution of impurities to remarkably low levels (1.13% for Al, 0.65% for Fe, 2.70% for Th, 10.5% for U, and 1.82% for F). However, the process efficacy was significantly compromised when applied to a high-fluorine concentrate (GF-1), attributed to the competitive formation of insoluble rare earth fluorides. This work presents a promising and selective hydrometallurgical strategy for treating low-fluorine rare earth concentrates, offering substantial potential for reducing environmental impact and operational costs.