Selective extraction of dysprosium from acidic solutions containing dysprosium and neodymium through emulsion liquid membrane by Cyanex 572 as carrier

Abstract

The selective extraction of Dysprosium (Dy) from acidic solutions also containing Neodymium (Nd) was studied using an Emulsion liquid membrane (ELM). Cyanex 572 was successfully applied as carrier. The liquid membrane phase consists of kerosene as diluent, Span 80 as surfactant, Cyanex 572 as carrier, and hydrochloric acid solution as stripping phase. Initially, the effects of different parameters such as carrier concentration, stirring speed, feed phase pH, surfactant concentration and their interactions on Dy extraction were investigated and the values of them were optimized by response surface methodology. Based on the results, the role of pH is very important in the ELM process for extraction of Dy by Cyanex 572. Thereafter, the selectivity of the membrane, represented by extraction, enrichment, and separation factor, was analyzed systematically with a view to optimizing the emulsion stability. The effect of important operating parameters governing the extraction and selectivity in ELM process namely feed phase pH; carrier and stripping phase concentration, initial concentration of Dy and Nd, and time of extraction have been investigated. It was found that it is possible to selectively extract 98.99% of Dy from the acidic feed solution containing Dy and Nd though ELM after 10min and maximum enrichment and separation factor can be achieved under the optimum conditions.