EXTRACTION AND SEPARATION OF SCANDIUM FROM RARE-EARTHS BY ELECTROSTATIC PSEUDO-LIQUID MEMBRANE

Electrostatic pseudo liquid membrane (ESPLIM), developed in this laboratory, is a novel chemical separation technique. In this paper, a study has been conducted on extraction, preconcentration and separation of scandium from dilute aqueous solution and multicomponent mixtures by ESPLIM. The effects were studied on the scandium extraction by the type of extractant and its concentration, applied field, the materials of the baffle plate, the pH value and the flow rate of feed solution, and scandium concentration in the feed. A useful way of representing the leakage and ''swelling'' rates in ESPLIM is proposed, in such a way that the leakage rate and swelling rate can be easily detected. The separation of scandium from aluminium, rare earths, iron, and other elements was performed with satisfactory separation factors. The experimental results demonstrated that the concentration of scandium in the organic phase in the ESPLIM process was much lower than its equilibrium concentration in the solvent extraction, which confirms the nonequilibrium feature of the ESPLIM process. ESPLIM seems to be a very convenient, effective and economic method for separating and preconcentrating scandium.