Poster (EARTH)

[PE1-032] Enhancement of Ag leaching from waste X-ray film in HNO₃ solution by adding methyl ethyl ketone(MEK)

○Hyeonji JO¹, Keoungkeun YOO¹ (1. Korea Maritime and Ocean University)

Keywords:waste X-ray film, silver, HNO3 leaching, MEK

X-ray film contains polyester and 1.5-2% silver which is recovered and reused. It is possible to leach the silver using HNO_3, because silver is linked to gelatin in the emulsion layer. In the conventional HNO₃ leaching process, since all silver was not leached even at high temperature and concentrated HNO₃, further processes such as incineration followed by leaching must be required. This study is performed to improve the leaching efficiency of silver by adding MEK, which could increase specific surface area by detach emlusion layer from waste X-ray film. Two leaching experiments set were conducted in this study. First experiment was leaching of X-ray after separating emulsion layer from X-ray films by MEK. Second leaching experiment was performed by adding MEK in HNO₃ solution. In the first leaching tests, 100% of silver was leached, within 120 minutes, in 1M HNO₃ at 50 °C and 400 rpm with 10 g/L pulp density after separating. In the second tests, 95% of silver was leached in 1M HNO₃ solution at 50 °C and 400 rpm with 10 g/L pulp density and 5% MEK addition. These results indicate that the addition of MEK enhanced the leaching efficiency of silver from waste X-ray films compared with the conventional process.