JPS6115425B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for regenerating a bleach-fix solution. In particular, it relates to the reclamation of used bleach-fix solutions by improved aeration methods. Image-exposed silver halide color photographic materials are
When color development is performed with an alkaline aqueous solution containing an aromatic primary amine compound or its derivative, a silver image and a dye image are formed. Silver produced during development and unreacted silver halide are dissolved and removed from the color photographic material in a bleach-fixing step. This bleach-fix step is carried out using a bleach-fix solution containing an iron() chelate compound and a silver halide solvent. The iron() chelate compound in the bleach-fix solution oxidizes the developed silver during processing and is itself reduced to a divalent ferrous salt. On the other hand, the silver ions produced by oxidation are dissolved by the fixing agent, so as processing continues, ferrous salts and silver complex salts gradually accumulate in the bleach-fixing solution, reducing its activity. It can no longer be used in the bleach-fixing process. To prevent this, the bleach-fix solution with reduced activity is drained from the tank as an overflow solution, and an appropriate amount of replenisher is added to the remaining solution. Disposal is not desirable from the point of view of environmental pollution or from an economic point of view. Several methods have been proposed for restoring the activity of such used bleach-fix solutions to a level that allows them to be reused. For example, methods are known in which an oxidizing agent such as hydrogen peroxide, ozone, persulfate, etc. is added to a used bleach-fix solution, or a method is introduced in which air is introduced. These methods are described in Japanese Patent Application Laid-Open No. 46-781.
No. 47-13933, No. 48-66838, No. 50-
It is described in publications such as No. 78328 and No. 50-101027. Other methods include a method in which a used bleach-fix solution is brought into contact with iron wool and air (Japanese Unexamined Patent Publication No. 48-3624), an electrolytic oxidation method (Unexamined Japanese Patent Publication No. 48-3624),
18191, 50-87029, and 51-19535). Among these methods, the regeneration method by aeration is the most commonly used. In the method of adding an oxidizing agent, sulfite ions and thiosulfate ions in the liquid are oxidized and unnecessary substances are accumulated in the regenerating liquid, so it is necessary to replenish the amount and at the same time remove the accumulated Must be disposed of. Iron wool contact methods or electrolytic oxidation methods are less common because they require long reactions to regenerate the liquid. The regeneration method by aeration has the advantage that it can be carried out with relatively simple equipment, the regeneration proceeds quickly, and there is little decomposition of sulfite ions and thiosulfate ions. However, since such a regeneration method using aeration generates a very large amount of foam, it is necessary to add various antifoaming agents to the liquid regenerated by this method. Various types of antifoaming agents are known, but one must be selected from among these that provides sufficient antifoaming effects without adversely affecting the bleach-fixing solution. Further, when a large amount of antifoaming agent is used, the desilvering ability usually decreases. SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for regenerating used bleach-fix solutions by improved aeration with less foam generation. Another object of the present invention is to provide a bleach-fix solution regenerated by highly efficient aeration. Such an object of the present invention is to direct the used bleach-fix solution, which is cyclically supplied from the storage tank by a popper, toward the liquid level of the liquid storage tank filled with the used bleach-fix solution. This is achieved by aerating the used bleach-fixing solution by injecting it as a jet solution from above and injecting the jet solution together with air and bubbles generated at this time into the solution in the reservoir tank. Spent bleach-fix solution is generated when imagewise exposed color photographic material is processed with a bleach-fix solution after color development. A method of employing this bleach-fixing process in a color processing process is described, for example, in US Patent No.
It is described in Publication No. 3582322, etc. In this case, the color developer is generally used, and is an alkaline aqueous solution containing an aromatic primary amine compound or a derivative thereof as a developing agent, preferably containing benzyl alcohol. As the developing agent, for example, N.N-diethyl-P-phenylenediamine,
4-Amino-N-ethyl-N-β-hydroxyethylaniline, 3-methyl-4-amino-N-ethyl-P-methanesulfamide ethylaniline sesquisulfate monohydrade, 3-methyl-
4-amino-N-ethyl-N-β-hydroxyethylaniline, 3-methyl-4-amino-N・N
- Sulfate or hydrochloride of diethylaniline can be mentioned. Other known additives such as alkali metal salts of sulfite, carbonates, bisulfites, bromides, iodides, antifoggants, and development accelerators may be contained. The bleach-fix solution contains an iron chelate compound and a silver halide solvent. As the iron chelate compound, a ferric complex salt of an aminopolycarboxylic acid or a polycarboxylic acid can be used. Examples of aminopolycarboxylic acids include nitrotriacetic acid, ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, ethylene glycol bis(aminoether)tetraacetic acid, diaminopropanoltetraacetic acid, N-hydroxyethylethylenediaminetriacetic acid, ethyliminodipropionic acid, and the like. Polycarboxylic acids include malonic acid, ethylmalonic acid, tartaric acid, malic acid,
Diglycolic acid and the like can be mentioned. Examples of silver halide solvents to be coexisted with these bleaching agents include sodium thiosulfate, ammonium thiosulfate, sodium thiocyanate, ammonium thiodianate, thioureas, thioglycols, and organic diols. These bleach-fix solutions may contain known additives such as PH buffers, sulfites, and the like. When aerating a used bleach-fix solution, it is usually preferable to aerate the solution after removing some or all of the dissolved silver complex salts as metallic silver or water-insoluble silver salts by an appropriate method. Methods for recovering silver from bleach-fix solutions are well known in the art, such as silver precipitation, metal displacement, electrolytic recovery, and the like. These methods are described in “Present
Status of Silver Recovery in Motion Picture
Lavoratories”, Journal of the SMPTE, No. 74
Volume (June 1965), pages 505-513. The metal replacement method uses iron wool as the metal,
This is achieved by the device described in US Pat. No. 3,369,801. In addition, the electrolytic recovery method has been patented in the UK.
This can be achieved by using the silver recovery electrolytic cells described in Publications No. 916348 and No. 1123168. In this case, the appropriate current density is about 80 amperes or more per square meter. The amount of silver recovered from the bleach-fix solution by these methods is such that the silver concentration in the bleach-fix solution is less than about 2 g of silver per solution, preferably 0.5 silver per solution.
It is preferred to recover an amount of silver that reduces the amount of silver to less than 1.5 g. The process of the invention can be carried out batchwise or continuously. In other words, the batch method is a method in which the used bleach-fix solution is regenerated separately from the bleach-fixing process, and the continuous method is a method in which the solution that overflows from the tank during the bleach-fix process is recycled after silver recovery. Then, a replenisher is added and this is returned to the bleach-fixing process. The term "color photographic material" as used herein refers to a color photographic material using silver halide, such as color photographic paper, color negative film, reversal film for color slides, and reversal color photographic paper for duplication. , general term for ordinary film such as color negative or positive film for motion pictures. The present invention will be explained below with reference to the drawings. Fig. 1 shows an embodiment of a liquid regeneration tank used in the method of the present invention, Fig. 2 shows an embodiment of a conventional liquid regeneration tank, and Fig. 3 shows an embodiment of a liquid regeneration tank used in the method of the present invention. 1 shows an embodiment of a continuous flowchart. In FIG. 1, the liquid regeneration tank according to the present invention is composed of a liquid storage tank 1, a liquid circulation device 2, and a jet nozzle 3. The injection hole of the jet nozzle 3 should be installed at a position above the liquid level 5 of the used bleach-fix solution 4 filled in the liquid storage tank 1. Furthermore, the position of the injection hole is preferably below the water level that rises when the replenisher is filled after the aeration of the used bleach-fix solution 4 is completed. In this case, the circulation device 2 can automatically stir the liquid. The jet liquid 6 jetted from the jet nozzle 3 is jetted toward the liquid surface 5 from a direction perpendicular to the liquid surface 5 or from a direction inclined at an appropriate angle. The liquid storage tank 1 is suitably made of glass, hard rubber, wood, metal or synthetic resin, particularly preferably polyvinyl chloride, polymethyl methacrylate, polyethylene, polypropylene, polystyrene, or formaldehyde resin.
In the case of metal, stainless steel is preferred. Generally, a liquid storage tank 1 having a capacity of 30 to 40 is suitable, but it may be larger or smaller than this. The circulation device 2 includes a pipe 7 installed below the liquid storage tank 1, a pipe 8 that introduces the liquid supplied from the pipe 7 into the jet nozzle 3, and a pump that can mechanically send the liquid from the pipe 7 to the pipe 8. Consists of 9. The output of the pump 9 is not limited by factors such as the size of the tank and the time required for regeneration, but a suitable range is 100W to 500W, and the circulation rate of the liquid in this case is 40/min to 200/min. minutes is appropriate. However, the preferred output of the pump is
100W to 150W, liquid circulation rate is 40/min to 80%
/minute. The jet nozzle 3 can be appropriately selected from metal, synthetic resin, or the like. The injection hole of the jet nozzle 3 has a slit shape, a circular shape,
A shape such as a rectangular shape can be appropriately used. The jet liquid 6 from the jet nozzle 3 has enough energy to jet the bubbles and air of the foam layer 10 generated above the liquid level 5 into the used bleach-fix solution 4, and therefore The area of the injection hole can be made as small as possible so that the supplied liquid becomes the jet liquid 6 with sufficient energy. Generally, when the liquid circulation rate is 40/min to 200/min, the appropriate area of the injection hole is 10 cm ² or less, preferably 2.5 cm ² or less, but the area is suitable for the amount of liquid supplied per unit time. The size of the injection hole can be changed depending on the capacity of the liquid storage tank 1, etc. Also, the jet nozzle described in Japanese Patent Application Laid-open No. 77406/1984 can also be used. The injection hole of the jet nozzle 3 should be installed at a position above the liquid level 5 of the used bleach-fix solution 4 as described above, but more generally, the jet solution is injected into the used bleach-fix solution 4. For example, 40
In the case of used bleach-fix solution 4, the water level is about 3
cm to 6 cm, the injection hole should be installed above this. The arrows in FIG. 1 indicate the approximate flow of the jet liquid 6, bubbles, and air injected into the liquid 4 from the injection holes. In FIG. 2, in order to aerate the used bleach-fix solution 12 filled in the storage tank 11, air is blown into the used bleach-fix solution 12 from an air pump 13 installed below the storage tank 11. be able to. However, in this conventional method, the used bleach-fix solution 12 is regenerated by aeration, but a large amount of foam layer 15 is formed on the solution surface 14. Specifically, 40 liters of used bleach-fix solution 12 is heated to 25 liters using a 150W air pump 13.
When aerated for minutes, a foam layer 15 of about 20 cm to 30 cm is formed. Therefore, a considerable amount of antifoaming agent is added to the bleach-fix solution regenerated by the regeneration tank shown in FIG. Furthermore, as is clear from the examples described below, the regeneration efficiency cannot be said to be high. FIG. 3 shows a continuous flowchart using the liquid regeneration tank 16 according to the present invention in the bleach-fixing process. The overflow liquid from the bleach-fix tank 17 is introduced into the silver recovery device 18 to remove part or all of the silver complex salts dissolved from the used bleach-fix liquid as metallic silver, and this liquid is transferred to the collection tank 19. Store. This collection tank 19
When a certain amount of liquid is stored, the pump 20 transfers the liquid to the liquid regeneration tank 16. The above-described operation is carried out in the liquid regeneration tank 16 for 15 minutes to 90 minutes, preferably 20 to 60 minutes.
The ferrous salt is converted back to the ferric chelate complex by running for a minute. Furthermore, a regenerant tank 21 is filled with a replenishing solution that can replenish the required amount of compounds necessary for regenerating the solution in accordance with the formulation used in the bleach-fixing process.
It is added from That is, a bleach-fix solution usually contains about 5 to 200 g of an iron chelate compound and about 5 to 200 g of an iron chelate compound.
Since it contains thiosulfate and also appropriate additives, the amount that is lacking due to use can be supplemented with a replenisher. The bleach-fix solution thus regenerated is stored in the replenishment tank 22, from which the regenerated bleach-fix solution can be appropriately introduced into the bleach-fix process. Hereinafter, the present invention will be explained according to examples. Example 1 A bleach-fix solution having the following composition was used. Ammonium thiosulfate 120g Anhydrous ammonium sulfite 20g Sodium iron() ethylenediaminetetraacetate
80g Disodium ethylenediaminetetraacetate 2g Add water and adjust the pH to 1 to 6.8 Color photographic paper (Oriental Color Paper:
(manufactured by Oriental Photo Industry Co., Ltd.) was printed using Oriental Rapid Labo 200 (manufactured by Oriental Photo Industry Co., Ltd.), and processed in the following order: color development, bleach-fixing, washing, and stabilization. This bleach-fix solution was used until the content of silver complex salts accumulated in the bleach-fix solution reached approximately 3.0 g/silver. The concentration of ferrous salt at this time was 17.4 g/in terms of iron () ions. The thus generated used bleach-fix solution 40 was introduced into an electrolytic cell, where it was electrolyzed for 3 hours. The cell voltage was set at 0.75 volts and 1.2 amps. The silver concentration after 3 hours was 2.0 g/,
Further, the concentration of ferrous salt was 14.0 g/. The electrolytically treated bleach-fix solution 40 was introduced into a solution regeneration tank according to the present invention as shown in FIG. Hitachi OVC-MH-150W (Hitachi, Ltd.) as a pump for liquid circulation system
The liquid was circulated for 25 minutes at a rate of 80 min. The injection hole of the jet nozzle has a slit-like shape, and the area of the slit surface is (width) 6 mm x
(Length) It was 27mm. The concentration of ferrous salt after this treatment was 0.03 g/. Further, the foam height at this time was about 1 cm, and the generation of foam was extremely small. Further, the bleach-fix solution 40 after the same electrolytic treatment was introduced into the solution regeneration tank shown in FIG. 2, and aerated for 25 minutes using the same pump. The concentration of ferrous salt after this treatment was 7.92 g/. Furthermore, this aeration was continued for 1 hour, and the concentration of ferrous salt was measured at this time and was 2.05 g/.
At this time, immediately after the start of aeration, bubbles were generated rapidly, and finally the bubbles overflowed from the liquid storage tank. The generation of this foam gradually decreased with continued aeration, and the foam height after 1 hour was approximately 20 cm. Example 2 Using the liquid regeneration tank shown in FIG.
Replenishment solution with the following composition for 40 minutes
After adjusting the pH to 6.8 with acetic acid, the regenerating solution was used in the bleach-fixing process of the Oriental Rapids Lab 200 described in Example 1 to process the same color photographic paper. Replenishment solution Sodium thiophrate 24g Anhydrous sodium sulfite 20g Sodium iron() ethylenediaminetetraacetate
6g Disodium ethylenediaminetetraacetate 2g Add water to bring the total amount to 1. At this time, the color developing solution and stabilizing solution used had the following formulation. Color developer 4-(N-ethyl-N-β-methanesulfonamidoethyl)amino-2-methylaniline sulfate
5 g Benzyl alcohol 20 ml Ethylene glycol 15 ml Anhydrous sodium carbonate 35 g Anhydrous sodium sulfite 3 g Potassium bromide 0.6 g Hydroxylamine sulfate 3 g Stabilizing liquid with water to make 1 volume Boric acid 5 g Sodium metaborate (4 Water salt) 3g Potassium alum 15g Sodium citrate 5g Add water to make a total volume of 1. The same procedure as above was carried out except that the liquid regeneration tank shown in Fig. 2 was used. The bleach-fix solution regenerated by the solution regeneration tank shown in FIG. 1 was designated as A, and the bleach-fix solution regenerated by the solution regeneration tank shown in FIG. 2 was designated as B, and the desilvering properties and color density were measured. Desilvering property was measured by the optical density of the bare part. The results are shown in Table 1.

[Table] B indicates blue)

[Brief explanation of the drawing]

FIG. 1 shows a cross-sectional view of an embodiment of an apparatus according to the method of the present invention, FIG. 2 shows a cross-sectional view of a conventional apparatus, and FIG. 3 shows a device using the method of the present invention. A flowchart of the bleach-fixing process is shown. 1: Liquid storage tank, 2: Liquid circulation device, 3: Jet nozzle, 4: Used bleach-fix solution, 5: Liquid level,
6: Jet liquid, 7, 8: Pipe, 9: Pump,
10: foam layer, 11: liquid storage tank, 12: used bleach-fix solution, 13: air pump, 14: liquid level, 1
5: Foam layer, 16: Liquid regeneration tank, 17: Bleach-fixing liquid tank, 18: Silver recovery device, 19: Collection tank, 20: Pump, 21: Regenerant tank, 22:
refill tank.

Claims (1)

[Claims] 1. Aim the liquid level of the storage tank filled with used bleach-fix solution generated when color photographic materials are processed with a bleach-fix solution containing an iron chelate compound and a silver halide solvent. Used by injecting the used bleach-fix solution, which is cyclically supplied from above, as a jet liquid from above the liquid surface, and injecting air and generated bubbles together with this jet liquid into the liquid in the liquid storage tank layer. A method for regenerating a bleach-fixing solution, which is characterized by aerating the used bleach-fixing solution.