Scandium Extraction from Nickel Processing Waste Using Cyanex 923 in Sulfuric Medium

Extraction of scandium (Sc) from nickel processing residue using Cyanex 923 was studied. Cyanex 923 showed better selectivity for Sc compared with the other metallic components in the residue. Scandium was extracted by solvent extraction via a solvation mechanism. The aqueous-to-organic (A/O) phase ratio was set at 1:2. An increase in the scandium extraction rate was observed when increasing the concentration of H + . Cyanex 923 was shown to be more selective for Sc than Fe. Coextracted Fe was removed from the organic phase by 3 mol L −1 H 2 SO 4 scrubbing with Sc loss of 1.3%. Stripping of scandium from the organic phase of 84.3% was achieved using 4% oxalic acid solution. The precipitated scandium oxalate was recovered by filtration and calcination. The obtained scandium oxide presented minimum purity of 99.0%.