Spent \(\text {Ag}\) / \(\alpha \) - \(\text {Al}_{2}\text {O}_3\) catalysts, widely used in ethylene epoxidation, are promising secondary sources of silver. Most existing methods for \(\text {Ag}\) extraction from spent \(\text {Ag}\) / \(\alpha \) - \(\text {Al}_{2}\text {O}_3\) are complex, environmentally polluting, and have low recovery rates. Additionally, chlorination inhibitors introduced during epoxidation reduce the silver recovery rate owing to the formation of silver chloride on the catalyst surface. This study addresses these challenges via a novel approach for the efficient recovery of silver from metallic silver and silver chloride, which combines leaching via cerium oxidation and ammonia complexation with electrodeposition, affording a total silver recovery rate of 98.26%. An orthogonal experimental approach was used to assess the effect of leaching conditions on the \(\text {AgCl}\) leaching ratio and to determine the individual impact of various experimental parameters on the reaction. Orthogonal analysis indicated that ammonia concentration had a more significant effect than stirring speed or temperature. The optimal leaching parameters yielded an \(\text {AgCl}\) leaching rate of 98.71%, resulting in a total silver recovery rate of 99.87%. The electrodeposition efficiency of the ammoniacal silver solution reached 99.99% under optimized conditions. This process enables closed-loop recycling of ammonia and cerium solutions, achieves near-zero liquid discharge, and demonstrates environmental and economic advantages.
