GB2226153A - Stripping silver halide emulsions from supports - Google Patents
Stripping silver halide emulsions from supports Download PDFInfo
- Publication number
- GB2226153A GB2226153A GB8828594A GB8828594A GB2226153A GB 2226153 A GB2226153 A GB 2226153A GB 8828594 A GB8828594 A GB 8828594A GB 8828594 A GB8828594 A GB 8828594A GB 2226153 A GB2226153 A GB 2226153A
- Authority
- GB
- United Kingdom
- Prior art keywords
- water
- wash tank
- silver halide
- coated
- tank
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 229910052709 silver Inorganic materials 0.000 title claims abstract description 19
- 239000004332 silver Substances 0.000 title claims abstract description 19
- 239000000839 emulsion Substances 0.000 title claims abstract description 17
- -1 silver halide Chemical class 0.000 title claims abstract description 11
- 238000000034 method Methods 0.000 claims abstract description 22
- WQYVRQLZKVEZGA-UHFFFAOYSA-N hypochlorite Chemical compound Cl[O-] WQYVRQLZKVEZGA-UHFFFAOYSA-N 0.000 claims abstract description 15
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 14
- 239000000463 material Substances 0.000 claims abstract description 13
- 239000000523 sample Substances 0.000 claims abstract description 11
- 102000004190 Enzymes Human genes 0.000 claims abstract description 8
- 108090000790 Enzymes Proteins 0.000 claims abstract description 8
- 229940088598 enzyme Drugs 0.000 claims abstract description 8
- 102000013142 Amylases Human genes 0.000 claims abstract description 3
- 108010065511 Amylases Proteins 0.000 claims abstract description 3
- 235000019418 amylase Nutrition 0.000 claims abstract description 3
- 229940025131 amylases Drugs 0.000 claims abstract description 3
- 102000004882 Lipase Human genes 0.000 claims abstract 2
- 108090001060 Lipase Proteins 0.000 claims abstract 2
- 239000004367 Lipase Substances 0.000 claims abstract 2
- 235000019421 lipase Nutrition 0.000 claims abstract 2
- SUKJFIGYRHOWBL-UHFFFAOYSA-N sodium hypochlorite Chemical compound [Na+].Cl[O-] SUKJFIGYRHOWBL-UHFFFAOYSA-N 0.000 claims description 2
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical group C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 claims 1
- 229910052708 sodium Inorganic materials 0.000 claims 1
- 239000011734 sodium Substances 0.000 claims 1
- 239000003643 water by type Substances 0.000 claims 1
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 abstract description 9
- 108091005804 Peptidases Proteins 0.000 abstract description 6
- 239000004365 Protease Substances 0.000 abstract description 4
- 102000035195 Peptidases Human genes 0.000 abstract description 3
- 238000010438 heat treatment Methods 0.000 abstract 1
- 239000002585 base Substances 0.000 description 12
- 102100037486 Reverse transcriptase/ribonuclease H Human genes 0.000 description 3
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 2
- 108010010803 Gelatin Proteins 0.000 description 2
- 239000000460 chlorine Substances 0.000 description 2
- 229910052801 chlorine Inorganic materials 0.000 description 2
- 239000011248 coating agent Substances 0.000 description 2
- 238000000576 coating method Methods 0.000 description 2
- 229920000159 gelatin Polymers 0.000 description 2
- 239000008273 gelatin Substances 0.000 description 2
- 235000019322 gelatine Nutrition 0.000 description 2
- 235000011852 gelatine desserts Nutrition 0.000 description 2
- 108091005508 Acid proteases Proteins 0.000 description 1
- 239000005708 Sodium hypochlorite Substances 0.000 description 1
- 229910052783 alkali metal Inorganic materials 0.000 description 1
- 238000010009 beating Methods 0.000 description 1
- 238000004061 bleaching Methods 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 239000012141 concentrate Substances 0.000 description 1
- 239000010970 precious metal Substances 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 102000004169 proteins and genes Human genes 0.000 description 1
- 108090000623 proteins and genes Proteins 0.000 description 1
- 229940024999 proteolytic enzymes for treatment of wounds and ulcers Drugs 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 239000013049 sediment Substances 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
Classifications
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03C—PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
- G03C11/00—Auxiliary processes in photography
- G03C11/24—Removing emulsion from waste photographic material; Recovery of photosensitive or other substances
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Silver Salt Photography Or Processing Solution Therefor (AREA)
Abstract
A method of treating material coated with a gelatino silver halide emulsion to strip the emulsions therefrom comprises passing the coated material into a wash tank which comprises water and either a water-soluble hypochlorite or an enzyme selected from proteases, lipases or amylases, the water in the bath being acted on by a plurality of ultrasonic probes to exceed the cavitation threshold. This method removes all layers from the support and silver can be recovered from the residue collected at the bottom of the task by a heating process. If ultra-sonics are not used, the support remains tacky and stripping takes far longer.
Description
REOOVERY OF SILVER FROM PHOTOGRAPHIC MATERIAIS This. in?ecri relates to a method of stripping gelatino emulsions fran the materials coated therewith. Silver is a precious metal and as considerable quantities of both coated photographic paper and film are produced year by year photographic films and a proportion of such coated material is waste material because of coating faults. On converting faults it is advantageous to be able to recover the silver from these coated materials as cheaply as possible.Further film base and also photographic paper base are expensive commodities and if these bases can be cleaned effectively they could be reused as photographic bases or in any event used for non-photographic prrposes. It was proposed in the early part of this century in U.S.P.
1065115 to treat coated photographic film base with proteolytic enzymes to remove the gelatino silver halide emulsion therefrom and recover the silver fran the removed emulsion. Further suggestions involving the use of enzymes for this purpose have been made more recently in B.P. 1396928 and in B.P. 1539610.
In B.P. 1199586 it states that attempts have been made to remove gelatino silver halide emulsions from film base by subjecting the film base to a bleaching process using chlorine or a chlorine yielding compound such as hypohlorite.
However none of the proposed methods have found Irucfi favour commercially because they are slow and the emulsion is not strip off the base very cleanly. In fact the old process of incinerating the base to recover the silver values from the ash is still employed.
However we have found a method of removing silver halide emulsion from photographic bases which is quicker than the prior art methods and yields a very clean base which could be reused.
Therefore according to the present invention there is provided a method of treating material coated with a gelatino silver halide emilsion to strip the emulsions therefrom which comprises passing the coated material into a wash tank which comprises water and either a water-soluble hypochlorite or an enzyme selected from proteases, lipaees or amylases, the water in the bath being acted on by a plurality of ultrasonic prcbes to exceed the cavitation threshold.
The cavitation threshold varies depending on temperature and other factors but an intensity of 0.35 Watts/cm2 produced by the ultrasonic prabes is usually sufficient to produce cavitation.
Thus a useful intensity range isfrom 0.35 tp 1.0 Watts/cm2 in the centre of the tank.
Preferably the temperature of the water in the wash tank is at an elevated temperature and most preferably within the range of 15 to 300C.
The preferred water-soluble hypochlorite is an alkali metal hypochlorite and in particular sodium hypochlorite.
A useful concentration to be present in the wash tank is from 0.5 to 2.0 % hypochlorite by weight.
The preferred enzymes are prcteases which are protolytic enzymes. These enzymes attack the central bads of protein nlecuIes. A particularly suitable prasease is Acid Protease marketed by B.D.H.
A useful amount of protease to be present in the wash tank is from 0.1 to 1 g/litre.
The preferred pH of the wash tank when protease enzymes are used is about 7.
coated film material is being treated it is preferred to use an enzyme in the wash tank. When coated paper material is being treated it is preferred to use a hypochlorite in the wash tank.
It is an important feature of the present invention that not only is the gelatino emulsion stripped off the film or paper base but so is any subbing layer. Thus clean non-tacky film and paper is obtained after applying the method of the present invention.
In the method of the present invention the gelatin which contains the silver or silver halide sinks to the bottom of the tank and concentrates there. Periodically this sediment can be drawn off fran the bottom of the tank and be sent away for recovery of the silver by a beating process.
In one test to illustrate the method of the present invention a stainless steel tank was used having a working capacity of 20 litres. This tank was 0.5 metres long by 0.2 metres wide and 0.2 metres deep. Three pairs of ultrasonic probes Robtained from case Ultrasonics of Runcorn) of 47 KH@ output were placed in the long side of the tank 0.1 metre below the top of the tank. Three along each side in pairs. The power output of each of these probes was 25 Watts. Thus the peak intensity along the axis of the tank when the probes were switdied was about 0.6 Watts/cm2. 20 litres of water heated to 300C was placed in the tank together with 10 g of prctease.
the the current was switched on cavitation of the water was observed and especially at the nodal point of each pair of probes.
A long length of 35 mm film having therean an essosed silver halide emulsion was then fed through the tank between the three pairs of probes.
The length of time for each metre of the length of film to be stripped of the emulsion was 45 seconds. The gelatin and silver sank to the bottom of the tank and the length of film was obtained free of all coating and non-tacky.
The ultrasonic prcbes where then switched off and another length of 35 mm film having thereon an exposed silver halide emulsion was then fed through the bath. This time it regquired 8 minutes residence time in the bath per metre to strip the gelatino mission off the film. Furthermore the film was very tacky after this time.
Prolonged treatment in the bath for example a further 10 minutes treatment time still did not yield a mon-tacky film.
The probes were then switched on again and a further length of coated film was fed three the tank between the three pairs of probes. Again only 45 seconds residence time per metre of film was required to strip the emulsion off the film and yield a non-tacky film. This shcws that the enqyme was still active.
Preferably before the protease is added to the water in the tank the probes are switched on for a few seconds to de-aerate the water.
Claims (9)
1. A method of treating material coated with a gelatino silver halide
emulsion to strip the emulsions therefran which comprises passing the
coated material into a wash tank which comprises water and either a
water-soluble hypochlorite or an enzyme selected from prateaees, lipases or amylases, the water in the bath being acted on by a
plurality of ultrasonic probes to exceed the cavitation threshold.
2. A method according to claim 1 wherein the ultrasonic probes produce an
intensity of from 0.35 to 1.0 Watts/cm2 in the centre of water wash
tank.
3. A method according to claim 1 wherein the temperature of the water in
the wash tank is from 15 to 300C.
4. A method according to claim 1 wherein the water-soluble hypochlorite
is sodium hypochloride is sodium hypoctlorite.
5. A method according to claim 4 wherein the concentration of hypcchlorate is from 0.5 to 2.0 % by weight of the water.
6. A method according to claim 4 wherein the material is photographic paper.
7. A method according to claim 1 wherein the concertration of en2yme in
the wash tank is fran 0.1 to lg/litre.
8. A method according to claim 7 wherein the pH of the waters in the wash
tank is substantially 7.
9. A method according to claim 7 wherein the material is photographic
film.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8828594A GB2226153B (en) | 1988-12-07 | 1988-12-07 | Stripping of silver halide emulsions from photographic supports |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8828594A GB2226153B (en) | 1988-12-07 | 1988-12-07 | Stripping of silver halide emulsions from photographic supports |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB8828594D0 GB8828594D0 (en) | 1989-01-11 |
| GB2226153A true GB2226153A (en) | 1990-06-20 |
| GB2226153B GB2226153B (en) | 1992-07-22 |
Family
ID=10648125
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8828594A Expired - Lifetime GB2226153B (en) | 1988-12-07 | 1988-12-07 | Stripping of silver halide emulsions from photographic supports |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2226153B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0745899A1 (en) * | 1994-07-30 | 1996-12-04 | BLUE-TECH GmbH | Process for making large scale transparent planar sheets from spent photographic films by physical and chemical-biological surface modification processes |
| CN105204286A (en) * | 2015-08-20 | 2015-12-30 | 陕西师范大学 | Secrete-associated black and white silver slat microfilm archive elimination method |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106244815A (en) * | 2016-08-31 | 2016-12-21 | 无锡中天固废处置有限公司 | A kind of method separating and recovering silver from photographic film |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1539610A (en) * | 1976-10-26 | 1979-01-31 | Ieronimo F | Process for stripping photographic materials |
-
1988
- 1988-12-07 GB GB8828594A patent/GB2226153B/en not_active Expired - Lifetime
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1539610A (en) * | 1976-10-26 | 1979-01-31 | Ieronimo F | Process for stripping photographic materials |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0745899A1 (en) * | 1994-07-30 | 1996-12-04 | BLUE-TECH GmbH | Process for making large scale transparent planar sheets from spent photographic films by physical and chemical-biological surface modification processes |
| CN105204286A (en) * | 2015-08-20 | 2015-12-30 | 陕西师范大学 | Secrete-associated black and white silver slat microfilm archive elimination method |
Also Published As
| Publication number | Publication date |
|---|---|
| GB8828594D0 (en) | 1989-01-11 |
| GB2226153B (en) | 1992-07-22 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 19931207 |