Yozo Ishizumi* and Hisao Imai**

(*Yonago Technical High School, Course of Materials Chemistry and
**Research Laboratory of Engineering Materials, Tokyo Institute of Technology)

Abstract

The silver deposits were examined in the three silver collection methods from the waste fixing solution of X-ray photograph,hydrogen peroxide method, electrolytic method and copper plate immersion. The deposit was identified as silver sulfide in the former two methods, but as mixture of silver and copper oxide (I) in the last method. Pure silver could not be obtained by the direct hydrogenation of silver sulfide, but it was obtained by a low temperature (400*C[Celsius degeree]) of silver chloride, which had been obtained by a nitric acid treatment followed by a sodium chloride treatment. The immersion method using copper plate was economical, but the silver was contaminated wiht the metal.

Key words: waste fixing solution, Bis (thiosulfat) silver (I) acidic ion Deposit, Composition, Hydrogenation