SELECTIVE SEPARATION of LANTHANUM USING DEHPA: INVESTIGATING THE POTENTIAL of EXTRACTING RARE EARTH ELEMENTS from ESKISEHIR BEYLIKOVA ORES

Abstract
Rare Earth Elements (REEs) are essential components of advanced technology applications such as renewable energy, electronics, and defense. Their unique magnetic, catalytic, and luminescent properties render them essential for the development of high-performance materials. However, efficient and selective separation of individual REEs is a significant challenge owing to their chemical and physical similarities. This study focuses on the selective separation of lanthanum (La) from complex mixtures of REEs as it is crucial for the sustainable extraction of Eskişehir Beylikova Rare Earth Ore. In this study, solvent extraction (SX), a critical method for separating REEs, was carried out by using di (2-ethylhexyl) phosphoric acid (DEHPA) as the extractant. The selection of DEHPA was done based on its proven efficiency in REE SX processes, which offers a balance between selectivity and extraction capacity. For this purpose, various DEHPA concentrations in the organic phase were studied to obtain the optimal conditions for the selective separation of La from the leach liquor. The synthetically prepared leach liquor contained 5000 ppm La, 400 ppm Pr, 800 ppm Nd, and 200 ppm Sm. Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) was utilized to determine the precise ion concentrations in the initial and extracted aqueous phases which ensured the accurate assessment of the extraction efficiency and selectivity. These initial findings revealed that the loading pattern is as follows: initial larger ionic radius La3+ (1.16 Å) loaded than after Pr3+ (1.13 Å), Nd3+ (1.11 Å), and Sm3+ (1.08 Å) came. The organic concentration was prepared ranging from 0.03M to 0.9M in kerosene. The loading efficiencies for La varied from 1.95% to 84.5%, whereas those for Sm, Pr, and Nd varied from 77.61% to 100%, from 41.69% to 99.17%, and from 27.78% to 97.68%, respectively, with increasing DEHPA concentrations. The outcomes demonstrated the feasibility of selective separation of La from other REEs using 0.03M DEHPA. The obtained results could be potentially adopted for the domestic production of REEs in the Eskişehir Beylikova Rare Earth Ores.
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Keywords
Rare Earth Elements, Solvent Extraction, Selective Separation, Lanthanum
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