Silver recovery from spent silver oxide button cells

The present work investigates a hydrometallurgical process for silver recovery from spent silver oxide button cells. The effects of acid concentration, reaction temperature, reaction time and shaking rate on the silver dissolution are investigated in detail. In addition, an investigation regarding the dissolution kinetics of silver is undertaken, and the activation energy is found to be 26 kJ/mol. Silver is selectively precipitated as silver chloride using potassium chloride solution, ensuring that other impurities remain in the solution. Silver chloride is subsequently reacted with metallic zinc powder in 1.0 M HCl to yield metallic silver of 99.99% purity. The process is proven to be easy, straightforward and environmentally friendly. (C) 2010 Elsevier B.V. All rights reserved.