Method for treating iron in a silver recovery process

A method of reducing the amount of iron in a standard photographic solution that forms a sludge or a precipitate during the recovery of silver from the standard photographic solution comprising the steps of:

• providing a standard photographic solution containing an amount of silver;
• selecting a source of a conjugate organic base;
• contacting the source of a conjugate organic base with the standard photographic solution to provide a concentration of from about 0.2 to about 78 milimolar of conjugate organic base in the standard photographic solution;
• recovering the silver from the chemical fluid using a metal replacement medium containing iron;
• wherein the source of a conjugate organic base is formed in a time release cake further comprising a binder;
• and
• wherein the binder is a polyvinyl alcohol and the ratio of the binder to the source of a conjugate organic base in the time release cake is about 60:40 by weight.

A method of reducing the amount of iron in a chemical fluid that forms a sludge or a precipitate during the recovery of silver from the chemical fluid comprising the steps of:

• providing a chemical fluid containing an amount of silver;
• selecting a source of a conjugate organic base;
• contacting the source of a conjugate organic base with the chemical fluid;
• recovering the silver from the chemical fluid using a metal replacement medium containing iron;
• wherein the source of conjugate organic base is located inside a container comprising a semipermeable membrane that maintains a concentration of conjugate organic base in the chemical fluid over a period of time;
• and
• wherein the semipermeable membrane is low density polyethylene that is from about 2 to about 4 thousands of an inch thick.