Solvent extraction of La, Nd, and Eu using a newly designed solutions spray system

• Published in: Minerals engineering Vol. 216; p. 108909
• Main Authors: Zubair Rahim, Muhammad, Ihsan Arol, Ali
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 15-09-2024
• Subjects: DEHPA; Rare earth elements; Solutions spray system; Solvent extraction; Solutions spray system; Rare earth elements; Solvent extraction; DEHPA
• ISSN: 0892-6875
• DOI: 10.1016/j.mineng.2024.108909

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•A setup is designed to overcome the problems faced by conventional SX techniques.•Micro-sized droplets enhanced the mass transfer between the immiscible phases.•Settling column design improved the phase separation time.•Overall product recovery and kinetics of the SX process were escalated.
This research covers a new continuous solvent extraction “solutions spray system” technique to extract lanthanum (La), neodymium (Nd), and europium (Eu) from chloride solution using DEHPA. This setup enhanced the extraction kinetics and mass transfer compared to the conventional mixer-settler by generating micro-sized droplets of the feed streams in the mixing chamber, causing speedy and better mass transfer, and the special design of the settling column boosted the separation process with improved quality products. Variables like pH, DEHPA concentration, ionic strength, and aqueous/organic phase ratio were studied to determine the performance of this setup. At the optimum values of these variables (2.0 pH, 0.303 M DEHPA, and 1.54 mol/L ionic strength), the percent extraction of La, Nd, and Eu was 95.03 %, 99.36 %, and 99.98 %, and the distribution ratio was 19.14, 155.25 and 4165 respectively, which showed the extraction in a single stage. Furthermore, the values of separation factors, SFEu/La = 6.69, SFEu/Nd = 5.33, and SFNd/La = 1.26 at 0.50 pH, showed the selectivity of these elements. Later on, McCabe Thiele diagrams were plotted for extraction and stripping sections to see the minimum number of theoretical stages for the complete recovery of REEs and their selective separation from each other.