On the cementation of silver with copper in nitrate solutions

Abstract

In this study, the effects of experimental parameters (required amount of cementator copper, concentration, pH, and temperature of the electrolyte, cementation duration, speed and type of stirring, etc.) on the recovery of silver from nitrate solutions by cementation with copper were investigated. Following results were obtained by the experimental work, carried out to find out the optimum conditions: The necessary amount of copper for the cementation was more than 2.5 times the theoretically required and there was no direct effect of initial silver concentration on the cementation efficiency, however it affected the morphology of the final cement silver. Cementation speed increased with increasing temperature, and the silver obtained was fine-grained showing good adhesion characteristics. Thickness of the silver layer formed atop the copper particles determined the diffusion rate (and thus, the cementation efficiency). Cementation efficiency was independent of pH, while between 1 and 3. Although increased, when pH = 0.5, but causing an increase in copper consumption due to the chemical dissolution and the purity of silver obtained linearly increased by rinsing, depending on its grain size and morphology.