US 5,688,401 AGranted

Apparatus for removing silver from spent photoprocessing solution

AssigneeEastman Kodak Company

InventorsThomas W. Bober, Terry W. Pearl, Dominick Vacco, David C. Yeaw

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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.

Claims33

Dependent claims

Apparatus for removing silver from spent photoprocessing solution, comprising:

means for providing a spent photoprocessing solution containing silver to be removed;
conduit means for receiving and passing the spent photoprocessing solution, the conduit means defining a mixing path and having a cross sectional flow area, an inlet end and an outlet end;
first means for delivering the spent photoprocessing solution at a first flow rate into the inlet end;
a source of precipitating agent for silver;
second means for delivering the precipitating agent at a second flow rate into the conduit means;
a source of flocculating agent for a precipitate formed by mixing the solution and the precipitating agent;
third means, located downstream of the second means by a first distance providing a first residence time sufficient for mixing of the solution and the precipitating agent and for forming a silver precipitate for flocculation, for delivering the flocculating agent at a third flow rate into the conduit means;
the outlet end of the conduit means being located downstream of the third means for delivering by a second distance, such that the first, second, and third flow rates, the cross sectional flow area, and the second distance provide a second residence time sufficient for forming clumps of flocculated particles of the silver precipitate;
the second residence time, the precipitating agent and the flocculating agent being such that the clumps of flocculated particles grow and agglomerate during movement of the solution and clumps through the second distance into enlarged clumps many of which individually extend across and substantially fill the cross sectional flow area, whereby individual enlarged, moving clumps substantially block passage of and strain from the solution remaining fine particles which then adhere to the enlarged, moving clumps as the enlarged clumps move to the outlet end;
and
a settling vessel for receiving clumps and solution from the outlet end and allowing the clumps to settle from the solution.

8 more elements

Apparatus for removing silver from spent photoprocessing solution, comprising:

means for providing a spent photoprocessing solution containing silver to be removed;
a mixing vessel;
first means for delivering the spent photoprocessing solution into the mixing vessel;
a source of precipitating agent for silver;
second means for delivering said precipitating agent for silver into the mixing vessel;
a source of flocculating agent for a precipitated formed by mixing the solution and the precipitating agent;
third means for delivering said flocculating agent for the precipitate into the mixing vessel, whereby flocculated particles are formed by the precipitate and the flocculating agent;
a settling vessel for receiving flocculated solids and any remaining liquid from the mixing vessel, the settling vessel having a sloped bottom wall and a bottom outlet for liquid and flocculated solids;
an inlet passage within the settling vessel, the inlet passage extending near the bottom wall and having a length providing a residence time sufficient for forming clumps of flocculated particles of the precipitate;
an outlet for clarified liquid on an opposite side of the settling vessel from the inlet passage and near an upper end of the settling vessel;
fourth means for delivering flocculated solids and liquid from the mixing vessel into the inlet passage;
and
beneath the settling vessel, a collecting and shipping vessel having an inlet, releasably connected to the bottom outlet of the settling vessel, for receiving the flocculated solids and any remaining liquid from the bottom outlet, for permitting the flocculated solids to settle to a bottom of the collecting and shipping vessel and the remaining liquid to move toward an outlet of the collecting and shipping vessel, whereby the settled flocculated solids gradually will agglomerate and compact to fill substantially the collecting and shipping vessel while at least a substantial part of the remaining liquid gradually will rise to an increasingly higher level and eventually pass from the collecting and shipping vessel, thereby permitting a filled collecting and shipping vessel to be disconnected from the bottom outlet of the settling vessel and replaced with an empty collecting and shipping vessel.

10 more elements

Apparatus for removing silver from spent photoprocessing solution, comprising:

a mixing vessel;
first means for providing into the mixing vessel a spent photoprocessing solution containing silver to be removed;
a source of precipitating agent for silver;
second means for delivering the precipitating agent into the mixing vessel;
conduit means, defining a mixing path and having a cross sectional flow area, an inlet end and an outlet end, for receiving and passing mixed solution from the mixing vessel;
a source of flocculating agent for a precipitate formed by mixing the solution and the precipitating agent;
third means for delivering the flocculating agent into the conduit means;
the outlet end of the conduit means being downstream of the third means for delivering by a distance providing a residence time sufficient for forming clumps of flocculated particles of the precipitate, the residence time, the precipitating agent and the flocculating agent being such that clumps of flocculated particles grow and agglomerate during movement of the solution and clumps through the distance into enlarged clumps many of which individually extend across and substantially fill the cross sectional flow area, whereby individual enlarged, moving clumps substantially block passage of and strain from the solution remaining fine particles which then adhere to the enlarged. moving clumps as the enlarged clumps move to the outlet end;
and
a settling vessel for receiving clumps and solution from the outlet end and allowing the clumps to settle from the solution.

7 more elements

Dependencies are inferred from the claim text.

Facts

Application: 08/648,477Filed 16 May 1996 · continuation in part
Priority: 4 Mar 1994
Granted: 18 Nov 1997
Term ends: Not estimatedThe source records don’t support an estimate.

Classification19 codes

B01F 25/4314
Straight mixing tubes with baffles or obstructions that do not cause substantial pressure drop; Baffles therefor: with helical baffles
B01F 25/4331
Mixing tubes wherein the shape of the tube influences the mixing, e.g. mixing tubes with varying cross-section or provided with inwardly…
B01J 19/243
Tubular reactors: spirally, concentrically or zigzag wound
C02F 1/5281
By flocculation or precipitation of suspended impurities: installations for water purification using chemical agents