Abstract: Silver is recovered from aqueous silver-bearing compositions such as seasoned photographic bleach-fixing compositions or other photoprocessing effluent that comprise certain aliphatic or aromatic sulfur-containing compounds that include a —N═C(SH)— group. The presence of these compounds in the silver-bearing compositions provides effective silver recovery, extended life for the silver recovery apparatus, and reduced maintenance.

Abstract: Spent solutions from photographic processors are fed into a conduit (18) to which subsequently are added precipitating agents from a first source (22) and flocculating agents from a second source (28); so that, well grown or ripened clumps of flocculated solids are formed along the conduit before being emptied into a gravity collecting vessel and shipping container (38) from which clarified liquids are displaced by a mass (50) of accumulated flocculated solids, typically through a filter (58, 142, 150, 158, 162, 166, 220)for removal of any unsettled fines. Many of the clumps of flocculated solids become enlarged enough to individually extend across and substantially fill a cross-sectional area of the conduit. As a result, the enlarged clumps substantially block passage of and strain from the solution remaining fine particles which then adhere to the clumps.

Abstract: Spent solutions from photographic processors are fed into a conduit (18) to which subsequently are added precipitating agents from a first source (22) and flocculating agents from a second source (28); so that, well grown or ripened clumps of flocculated solids are formed along the conduit before being emptied into a gravity collecting vessel and shipping container (38) from which clarified liquids are displaced by a mass (50) of accumulated flocculated solids, typically through a filter (58, 142, 150, 158, 162, 166, 220) for removal of any unsettled fines. Many of the clumps of flocculated solids become enlarged enough to individually extend across and substantially fill a cross-sectional area of the conduit. As a result, the enlarged clumps substantially block passage of and strain from the solution remaining fine particles which then adhere to the clumps.

Abstract: Spent solution from photographic processors are fed into a conduit (18) to which subsequently are added precipitating agents from a first source (22) and flocculating agents from a second source (28); so that, well grown or ripened clumps of flocculated solids are formed along the conduit before being emptied into a gravity collecting vessel and shipping container (38) from which clarified liquids are displaced by a mass (50) of accumulated flocculated solids, typically through a filter (58, 142, 150, 158, 162, 166, 220) for removal of any unsettled fines.

Abstract: Anions containing sulfur and oxygen, e.g. thiosulfate, can be catalytically reduced using a protonated anion ion exchange resin as a catalyst. The process is preferably conducted in an aqueous system and at a pH below about 8.