Improvement in the performance of solvent extraction operation using solutions spray system

The solvent extraction (SX) method is a widely used hydrometallurgical technique for extracting metals from leach solutions. SX helps in the recovery and selective separation of rare earth elements (REEs), which is not possible in the case of physical separation techniques. However, traditional SX processes face challenges such as limited mass transfer between immiscible liquids and slow mixing and separation kinetics. To address these issues, a new solution spray system was developed to enhance mass transfer during extraction while also reducing mixing and separation times. This system generates uniform micro-droplets in the mixing column, creating a well-mixed emulsion of the two immiscible phases and improving mass transfer efficiency. Additionally, its redesigned settling section enhances phase separation, consistently producing a high-quality final product that is fully separated from the raffinate. The newly-designed solutions spray system and the conventional mixer-settler system were analyzed in extracting La, Nd, and Eu from the chloride solution using organic solvent DEHPA. It was found that the maximum extractions were 95.03%, 99.36%, and 99.98% for La, Nd, and Eu respectively from a feed solution having 2.0 pH with 0.303 M DEHPA, using solutions spray system. On the other hand. The maximum extractions were 98.60% for Eu, 89.25% for Nd, and 73.68% for Eu in the case of mixer-settler system. The solutions spray system showed better performance because of the production of mono-sized micro droplets of the feed streams. McCabe Thiele diagrams were also plotted to see the theoretical counter-current stages for extraction and stripping stages.