Extraction of Silver from Waste X-ray Films by Thiosulphate Leaching

In this study, the recovery of silver from waste X-ray films (0.7% Ag) by ammoniacal copper thiosulphate leaching was studied. The experiments were designed using Taguchi L9 (3 3 ) experimental design. The effects of concentration of thiosulphate, (0.005-0.5 M S2O3 2), copper (0.005-0.5 M Cu 2+ ), and ammonia (0.005-1 M NH3) on the extent of silver recovery from X-ray films were investigated at three levels. The experimental data were analysed using a statistical software. The findings revealed that the concentration of ammonia (NH3) and thiosulphate (S2O3 2) were statistically the most significant factors affecting the recovery of silver, while the effect of concentration of copper (Cu 2+ ) was found to be insignificant over a reaction period of 0.5 h.