Recovery of cobalt from secondary sector using extraction in Cyanex 923

Abstract

A process for the recovery of pure Co(II) from spent Co-Mn and Co-Mo catalysts by its extraction in Cyanex 923 is described. The metal ion is partitioned in the organic phase as H2CoCl₄.2 Cyanex 923 and stripped with a solution of 1×10^-3 molL^-1 H₂SO₄. The extractant is stable towards prolonged contact with HCl and shows negligible loss in extraction capacity even after recycling for twenty cycles. The partition data have been utilized for developing conditions for the separation of Co(II) from other metal ions, viz., Mo(VI), AI(III), Cr(III), Fe(III), Mn(II), Ni(II), Cu(II), Zn(II) and Cd(II). The separation technique has been extended for the recovery of ~95% Co(II) from spent catalysts. The purity of the metal ions thus obtained approximates to 99%.