VIABILITY OF THE SEPARATION OF CD FROM HIGHLY CONCENTRATED NI-CD MIXTURES BY NONDISPERSIVE SOLVENT-EXTRACTION

The separation of nickel and cadmium from highly concentrated solution s by means of non-dispersive solvent extraction (NDSX) has been studie d in this work. Extraction and back-extraction processes were carried out simultaneously in a batch mode using two parallel modules and the organic phase flowing in a closed circuit. Starting with concentration s of 0.37 M of Cd and 0.37-0.68 M of Ni in the feed aqueous phase, 1 M of H2SO4 in the back-extraction phase, and using D2EHPA as extractant , the viability of the separation-concentration of Cd from that mixtur e has been confirmed. Under the experimental conditions, the separatio n process was run at a constant rate of mass transport, thus leading t o a selectivity factor in the concentration step rho=67 mol Cd/mol Ni. (C) 1998 Elsevier Science S.A. All rights reserved.