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:
Aug. 04, 1998
Filed:
Dec. 13, 1995
Yoshito Wakui, Sendai, JP;
Osamu Itabashi, Sendai, JP;
Abstract
Proposed is an efficient method for the highly selective recovery of silver value in an aqueous solution containing silver ions in a low concentration, such as depleted photographic fixing solutions, by extracting the silver ions from the aqueous phase with an organic solution containing 0,0-bis(2-ethylhexyl) hydrogen thiophosphate as an extractant solution and the silver ions contained in the extract solution are back-extracted with a hydrochloric acid solution containing thiourea. Alternatively, the silver-containing starting aqueous solution is contacted with beads of a porous resin bearing the thiophosphate compound so that the silver ions are selectively adsorbed on the resin beads and then the silver ions are leached out of the resin beads with an organic solvent.