Method for treating iron in a silver recovery process
US8114189B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 14, 2008 |
| Grant date | Feb 14, 2012 |
| Priority date | — |
| Expiry date | Jun 22, 2030 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03C5/3956
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A method of reducing or preventing the amount of iron sludge or precipitate that forms as a result of the recovery of silver from chemical solutions, such as a standard photographic solution. The method generally involves the introduction of a source of a conjugate organic base, such as a weak organic acid like citric acid or a salt of the conjugate organic base like a citrate salt, to the chemical fluid either before or during the silver recovery process. Preferably the source of conjugate organic base is introduced by combining it with a binder to form a time release cake or placing it in a container that has a semipermeable membrane that maintains the concentration of the conjugate organic base in the chemical fluid from about 0.2 to about 78 milimolar over a period of time.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.