Separation of Ag and Zn from Nitrate Leachate of Spent Silver Oxide Batteries by Solvent Extraction with Cyanex272

Abstract

The separation of Ag and Zn from the nitrate leachate of spent silver oxide batteries using Cyanex272 as an extractant was investigated. The extraction of Ag and Zn was affected by the concentrations of nitric acid and the extractant. Cyanex-272 selectively extracted Zn over Ag when the HNO 3 concentration was lower than 0.1 mol/L. The co-extracted Ag was removed by stripping with 1 mol/L thiourea. Stripping of Zn from the loaded Cyanex-272 was accomplished using 0.5 mol/L HNO 3 after the removal of Ag. The McCabe-Thiele diagrams for the extraction of Zn with Cyanex-272, the scrubbing tripping of Ag with thiourea, and the stripping of Zn with HNO 3 were constructed. The results were verified by simulated counter-current extraction and stripping experiments. Finally, a process for the separation of Ag and Zn from silver oxide batteries was proposed.