Optimizing Silver Extraction Potential from Waste X-Ray Films Using Acid and Alkaline Leaching Agents

Abstract In this study, the silver extraction potential from waste x-ray films using sodium hydroxide and nitric acid was studied. Sodium hydroxide and nitric acid of different concentrations were used as stripping solutions to determine the optimum leaching concentration. Optimum leaching time and leaching temperature were also investigated by varying the time and temperatures, respectively. The stripped solutions were analysed for silver concentration using Flame Atomic Absorption Spectrophotometer. Results obtained revealed that, for sodium hydroxide stripping, 26.6 mg kg −1 of silver ion was obtained at an optimum leaching concentration, time and temperature of 1.5 M, 900 minutes and 30 °C. For nitric acid stripping, a maximum concentration of 9830.6 mg kg −1 was obtained at optimum concentration, time and temperature of 4 M, 1,440 minutes and 30 °C. The result revealed that the concentration of leaching agent was a significant factor affecting silver recovery, with nitric acid possessing a much higher recovery rate compared to sodium hydroxide.