While I’m not entirely familiar with silver recovery from regular
film I am pretty well versed in the recovery from x-ray film. There
are primarily 2 available methods:
-
bath to remove silver (bath contains cyanide
mixture)>cartridge>refine -
bath to remove silver (bath contains a relatively non-toxic
protease based detergeant)>precipitation of silver>decant liquid
from silver sludge>dry silver sludge>smelt
The second method is the one now widely used in the industry as it
is less toxic. Silver is adhered to x-ray film by a gel formed from
animal fat rendering. A protease based detergeant dissolves this
layer fat allowing the silver to precipitate to the bottom of the
bath. The silver can then be recovered. The drying and smelting
process burns off any clinging gel leaving a pure silver product. I
do not recall the name of the protease based detergeant right off
but I do know that Eastman Kodak can tell you how to obtain it.
Good Luck! Liz PS. I am well versed in this because as an
environmental enforcement officer I have shut down one and helped to
straighten out several of these type facilities (commercial not DIY).