ENHANCED CERIUM RECOVERY FROM ACIDIC CHLORIDE VIA SYNERGISTIC EXTRACTION

Abstract

The increasing demand for light rare earth elements (LREEs), particularly cerium (Ce), has intensified the need for efficient and environmentally sustainable extraction methods. Conventional solvent extraction systems using single extractants often suffer from limited efficiency and raise environmental concerns due to the use of volatile organic compounds (VOCs). Therefore, improving extraction performance while minimizing environmental impact remains a significant challenge. This study aims to evaluate the effectiveness of synergistic extractant systems in enhancing the extraction efficiency of cerium from an acidic chloride medium. The extraction of Ce from an acidic chloride solution was carried out using binary combinations of trihexyl(tetradecyl)phosphonium bis(2,4,4-trimethylpentyl)phosphinate (Cyphos IL), di-(2-ethylhexyl) phosphoric acid (D2EHPA), tributyl phosphate (TBP), and trioctylmethylammonium chloride (Aliquat 336), all dissolved in kerosene. Equal volumes of the organic and aqueous phases were mixed at room temperature to assess Ce extraction efficiency. Results showed that all synergistic systems substantially improved Ce extraction over single extractants. The D2EHPA/Cyphos IL system exhibited the highest enhancement in extraction efficiency, achieving a 94.1% improvement, followed by TBP/D2EHPA (70.7%),  TBP/Cyphos IL (66.2%), D2EHPA/Aliquat 336 (51.6%), Aliquat 336/Cyphos IL (51.2%), and TBP/Aliquat 336 (42.0%). The superior performance of the D2EHPA/Cyphos IL system can be attributed to strong synergistic interactions between the ionic liquid and acidic extractant, which enhance metal complexation and transfer into the organic phase. In conclusion, synergistic extractant mixtures provide a highly effective and potentially greener approach for cerium recovery under ambient conditions, offering improved efficiency over conventional single-extractant systems while addressing environmental concerns associated with VOC emissions.