Recycling of Zn-C and Ni-Cd spent batteries using Cyphos IL 104 via hydrometallurgical route

Abstract

The study suggests hydrometallurgical routes for the recovery of zinc and cadmium from spent battery leachates using a novel extractant Cyphos IL 104 diluted in toluene and synthesis of zinc and cadmium oxides from the loaded organic phases. Leaching is carried out using 5 mol/L HCl and the composition of the leach liquors obtained from Zn-C and Ni-Cd spent batteries in g/L is Zn- 2.400, Mn - 4.870, Fe - 2.655 × 10−3, and Cd- 4.280, Ni- 89.60 × 10−3, Fe- 148.2 × 10−3, Co- 3.765 × 10−3, respectively. McCabe Thiele diagrams are drawn to determine the number of theoretical stages required for the quantitative extraction and stripping of zinc and cadmium and the data has been confirmed by counter current simulation studies. McCabe Thiele diagrams indicate two extraction stages for both zinc and cadmium at A/O = 1/1 and A/O = 3/2, respectively. EDTA (0.1 mol/L) and HNO3 (1.0 mol/L) are used as strippant for zinc and cadmium, respectively. Quantitative stripping of zinc and cadmium requires two and three counter current stripping stages, respectively at O/A = 1/1. Results of counter current extraction and stripping show quantitative recovery (>99%) of zinc and cadmium with high purity. Zinc and cadmium oxides have been synthesized from the loaded organic phase using precipitation followed by thermal decomposition of precursors at 400 °C. Synthesized materials were characterized by XRD, FE-SEM and EDX techniques. Zinc and cadmium oxide particles correspond to hexagonal zincite and cubic monteponite structures, respectively. The average particle size of zinc and cadmium oxides is 43 ± 13 nm and 55 ± 14 nm, respectively. The morphology of zinc and cadmium oxide particles is considered to be globular with particle agglomeration. The proposed methods are selective for zinc and cadmium. Results of present study have been compared with the reported data.