A selective recovery of zinc and manganese from the spent primary battery black mass as zinc hydroxide and manganese carbonate

The major challenge in zinc–carbon battery recycling lies in achieving selective separation of zinc and manganese while producing high-purity materials suitable for advanced applications. This study aims to develop a selective hydrometallurgical approach for recovering high-purity zinc and manganese from spent primary zinc–carbon battery black mass (BM), addressing environmental concerns from improper battery disposal. A three-stage sequential leaching process was employed, consisting of water leaching for impurity removal, alkaline leaching for selective zinc extraction as zincate ions, and glucose-assisted reductive acid leaching for manganese recovery. The BM composition was characterized using scanning electron microscope (SEM)–energy-dispersive X-ray (EDX) analysis, while recovered products were precipitated as Zn(OH) 2 and MnCO 3 and characterized using X-Ray diffraction (XRD), Fourier transform-infra red (FTIR), SEM–EDX, and elemental mapping techniques. SEM–EDX analysis revealed that BM contains high concentrations of Zn, Mn, C, Na, and K. The sequential leaching achieved excellent metal recovery with 98.2% zinc extraction efficiency and 91.2% manganese recovery, demonstrating high selectivity with minimal cross-contamination. XRD analysis confirmed the formation of crystalline ZnO/Zn 3 (OH) 4 (NO 3 ) 2 and pure rhodochrosite MnCO 3 . SEM analysis revealed spherical morphologies for both products, with high purity confirmed by FTIR and EDX mapping. This work presents the first comprehensive study combining glucose-assisted reductive leaching with alkaline selective extraction for simultaneous zinc and manganese recovery from Zn–C batteries, achieving superior separation efficiency compared to conventional single-stage approaches. The as-obtained high-purity products show promising potential for advanced applications in catalysts, Li-ion batteries, and supercapacitors.