Patents Assigned to Photographic Silver Recovery Limited
  • Patent number: 4299676
    Abstract: A process is provided for recovering silver and plastics material from photographic film. For exposed film, film is shredded or chopped, subjected to bleach treatment, washed, and subjected to fixing treatment, the fixing solution being circulated in closed circuit through an electrolytic silver recovery plant in which silver is deposited on one or more cathodes. For unexposed film, the bleach and washing steps can be omitted. For high silver recovery, the main fixing treatment is followed by a tailings treatment in fix solution, the tailings solution being circulated through a separate silver recovery unit of lower capacity and lower power. To maintain the fixing solution pH, a first wash in plain water is followed, before fixing, by a second wash in water treated with an alkaline chemical to raise its pH.
    Type: Grant
    Filed: March 27, 1980
    Date of Patent: November 10, 1981
    Assignee: Photographic Silver Recovery Limited
    Inventors: John H. Skinner, James S. Bentley