Preparation of silver powders in micron size from used photographic films via leaching–cementation technique

The results of a leaching study of used photographic films containing silver with nitric acid are presented. Effect of reaction time, reaction temperature and acid concentration on silver dissolution efficiency was determined. The results obtained show that leaching of about 98% of silver is achieved using − 2 mm spent (used) photographic film size at a reaction temperature of 90 °C for 50 min reaction time with 6% nitric acid concentration. Different solid:liquid ratios of 1:10 to 1:50 g/ml were also studied. Cementation study indicates that practically 100% of silver is deposited with addition of Zn metal powder. SEM photomicrographs show that sphere particles of about 1 μm diameter were obtained.