The development of low-cost compound eluent for the efficient removal of the residual ammonium from the weathered crust elution-deposited rare earth tailings, is highly attractive to meet the growing demands for green metallurgy. Herein, a ternary compound eluent composed of K, Mg, and Na was prepared for the first time, and its elution behavior and mechanism for the residual ammonium were investigated in detail. Results showed that the maximum ammonium elution amounts of 1702.9 mg/kg was achieved at a K/Mg/Na molar ratio of 5:6:4, which was much higher than the single eluents of K (1264.9 mg/kg), and Mg (1105.6 mg/kg), and Na (925.9 mg/kg). In addition, higher eluent concentration and faster flow rate would help to improve the elution efficiency. Besides, the dynamic kinetic study revealed that the residual ammonium elution was controlled by internal diffusion. Moreover, XPS analysis demonstrated that K, Mg, and Na ions were all involved in and promoted the residual ammonium elution. The novel ternary compound eluent had great potential application in the residual ammonium removal from the rare earth tailings.

中文翻译：

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三元复合淋洗液高效去除风化壳淋积稀土尾矿中残留铵

开发低成本复合淋洗液，有效去除风化壳淋积稀土尾矿中的残留铵，对于满足日益增长的绿色冶金需求具有很大的吸引力。在此，首次制备了由K、Mg、Na组成的三元复合洗脱液，并详细研究了其对残留铵的洗脱行为和机理。结果表明，当 K/Mg/Na 摩尔比为 5:6:4 时，铵的最大洗脱量为 1702.9 mg/kg，远高于 K（1264.9 mg/kg）和 Mg 的单一洗脱液。 （1105.6 毫克/千克）和钠（925.9 毫克/千克）。此外，较高的洗脱液浓度和较快的流速将有助于提高洗脱效率。此外，动态动力学研究表明残留铵洗脱是受内部扩散控制的。此外，XPS分析表明K、Mg和Na离子均参与并促进了残留铵的洗脱。新型三元复合洗脱液在稀土尾矿残铵脱除方面具有巨大的应用前景。