The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 03, 2000
Filed:
Aug. 13, 1998
Hailing Duan, Ridgewood, NJ (US);
William Lovell, St. Petersburg, FL (US);
Fuji Hunt Photographic Chemicals, Inc., Paramus, NJ (US);
Abstract
Process and apparatus for treating an aqueous effluent with high concentrations of silver and ferric/ferrous complexes using multiple additions of one or more water-soluble sulfur containing polymer chelating agents, with optional additions of non-polymeric sulfur containing compounds. The presence of a high concentration of both dissolved silver and ferric/ferrous complexes prevents efficient silver removal by precipitation and the achievement of a very low residual silver concentration. By using multiple additions of the chelating agent(s), a higher degree of silver removal can be achieved than would be possible with the same amount of chelating agents added in a single stage. Effluent from photo finishing operations, particularly minilabs, can be effectively treated so that there is essentially no silver remaining in the treated effluent.