JPS6341963B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for efficiently recovering silver from a photographic processing solution containing an iron compound having an organic acid as a ligand (hereinafter referred to as an organic acid iron chelate complex) and a water-soluble silver salt. Processing of silver halide color photographic materials includes two steps: color development and desilvering. That is,
When a color photographic material is color-developed, the exposed silver halide is reduced to silver, and at the same time, the oxidized aromatic primary amine developing agent reacts with the coupler to form a dye image. In the desilvering step, silver produced by development is oxidized by an oxidizing agent to silver halide, which is dissolved and removed by a silver halide solvent. As described above, the desilvering process includes the two steps of bleaching and fixing, but in actual photographic processing methods, there is a method in which the bleaching step and the fixing step are performed separately. Among these methods, there is a method in which a washing step is provided between the bleaching and fixing steps, or a method in which the fixing step is directly started from the bleaching step. There is also a bleach-fixing process in which both processes are performed simultaneously. Further, following the bath containing these soluble silver salts, a water washing step is usually provided. In recent years, the issue of environmental conservation and the saving of silver resources have become important, and there is a strong desire for a method to reduce pollution and a method to efficiently recover silver. Therefore, as a method to recover the silver flowing into the washing water and simultaneously reduce polluting substances from the washing water, a preliminary washing step (intermediate bath) is provided between the bath containing soluble silver salts and the subsequent washing step. It is also proposed that The following two methods are widely used to recover silver from a solution containing a soluble silver salt as described above. [1] A method of replacing molten silver by bringing it into contact with a base metal, which has a greater tendency to ionize than silver. [2] An electrolytic method in which silver is deposited on the cathode by electrolysis. However, these methods have various drawbacks. For example, the former method requires base metals (e.g. iron, aluminum, etc.) equivalent to silver ions, and since the base metal ions elute and accumulate in the processing solution, the processing solution after silver recovery must be reused. It becomes a big obstacle. Furthermore, in the case of bleach-fixing or fixing solutions containing organic acid iron chelate complexes, iron hydroxide is generated, which causes clogging of cartridges, etc., and has drawbacks such as reducing silver recovery efficiency. . Regarding the latter method, if the bleach-fix solution or fixer solution contains an organic acid iron chelate complex,
A part of the silver electrolytically deposited on the cathode is redissolved in the bleach-fix solution or fixer solution containing the organic acid iron chelate complex, which reduces the amount of silver deposited per unit charge (hereinafter referred to as current efficiency). have. Various proposals have been made to solve these drawbacks. For example, regarding the above method, that is, the electrolytic silver recovery method, Japanese Patent Application Laid-open Nos. 50-98837 and 52-26315
No. 52-115723, No. 53-32869, No. 53-
60391, West German Patent No. 233018, West German Patent No. 2429288,
Belgian Patent No. 780623, US Patent No. 3400056,
There are specifications or publications such as No. 3840455, No. 3964990, and No. 4069127. The methods described in these documents include electrolysis by adding a reducing agent while changing the potential, using a diaphragm, electrodialysis, automatic current control, liquid feeding,
Most of the techniques involve improving stirring methods or devices such as electrodes and plates. However, both have drawbacks such as insufficient current efficiency and large and complicated devices. Unlike these methods, the present invention relates to a technique for efficiently recovering silver from a photographic processing solution containing an organic acid iron chelate complex by utilizing a chemical processing method. Therefore, a first object of the present invention is to provide a method for efficiently recovering silver from a liquid containing an organic acid iron chelate complex and a water-soluble silver salt. A second object of the present invention is to provide a silver recovery method for efficiently recovering silver from a bleach-fix solution using an organic acid iron chelate complex as an oxidizing agent or a fix solution in which the organic acid iron chelate complex is mixed during the processing process. The goal is to provide the following. A third object of the present invention is to provide a silver recovery method for recovering silver with as little sulfite oxidation as possible during electrolysis of the bleach-fix solution, fixer solution, etc. A fourth object of the present invention is to provide a silver recovery method for recovering silver for reusing a liquid containing an organic acid iron chelate complex. Other objects of the invention will become apparent from the following description of the specification. As a result of various studies, the present inventor discovered that in a method for recovering metallic silver from a photographic processing solution containing an organic acid iron chelate complex and a water-soluble silver salt, by carrying out a metal nuclear exchange reaction with the organic acid iron chelate complex, A metal compound capable of forming a stable organic acid metal chelate complex is added to the above organic acid iron chelate complex.
It has been found that the above object can be achieved by a method of recovering silver in which silver is present in the photographic processing solution in an amount of 0.2 times the mole or more. According to the present invention, silver is deposited on the cathode from a solution containing a soluble silver salt and an organic acid iron chelate complex using a commonly used electrolytic device for fixing solution or bleach-fixing solution, and then left in the electrolytic solution for a long time. Even in this case, redissolution does not occur, and the current efficiency, that is, the amount of silver deposited per unit charge, can be recovered in a larger amount than in the past. Further, normally, when silver is recovered by electrolysis, decomposition of sulfite occurs and silver sulfide is finally produced, but in the method of the present invention, decomposition of sulfite is small. Further, according to the present invention, a regenerated fixer containing a soluble silver salt and an organic acid iron chelate complex can be reused without adversely affecting fixing properties when a silver halide photographic light-sensitive material is processed. In addition to the above, when the method of the present invention is used to improve the drawbacks of the silver recovery method using the base metal substitution method described above, the following effects can be obtained. for example,
If the method of the present invention is used to recover silver using a steel wool cartridge, it is possible to prevent iron from leaching out and precipitation, and furthermore, the silver recovery efficiency is significantly improved. The method of the present invention will be explained in more detail below. In the present invention, the photographic processing solution containing an organic acid iron chelate complex and a soluble silver salt includes a fixing solution, a bleach-fixing solution, a one-bath development bleach-fixing solution, a preliminary washing solution, a washing solution, and the like. In addition, examples of metal compounds that can form a stable organic acid metal chelate complex by performing a metal nuclear exchange reaction with the organic acid iron chelate complex according to the present invention include nickel compounds, zinc compounds, lead compounds, vanadium compounds, and lanthanum compounds. etc. These metal compounds are used in the form of salts such as halides, sulfates, nitrates, and acetates, or in the form of complex salts of chelating agents such as acetylacetone, phosphonocarboxylic acids, and polyphosphoric acids. Preferred specific example compounds will be listed next, but the present invention is not limited thereto. (Exemplary compounds) A-1 Zinc chloride A-2 Zinc bromide A-3 Zinc sulfate A-4 Zinc nitrate A-5 Zinc acetate A-6 Lead chloride A-7 Lead sulfate A-8 Lead nitrate A-9 Nickel chloride A-10 Nickel nitrate A-11 Nickel sulfate A-12 Nickel acetate A-13 Nickel bromide A-14 Nickel iodide A-15 Zinc acetylacetone complex A-16 2-phosphonobutane-1,2,4-tricarboxylic acid zinc complex A-17 2-phosphonobutane-2,3,4-tricarboxylic acid zinc complex salt A-18 Hexametaphosphate zinc complex salt A-19 Tripolyphosphate zinc complex salt A-20 Dimethylglyoxime zinc complex salt A-21 1,2-cyclohexanedione dioxime Zinc complex A-22 Acetylacetone lead complex A-23 2-phosphonobutane-1,2,4-tricarboxylic acid lead complex A-24 Hexametaphosphate lead complex A-25 Acetylacetone nickel complex A-26 2-phosphonobutane-1,2,4 - Tricarboxylic acid nickel complex salt A-27 Dimethylglyoxime nickel complex salt A-28 Tripolyphosphate nickel complex salt A-29 Hexametaphosphate nickel complex salt A-30 2-furyldioxime nickel complex salt A-31 Sodium orthovanadate A-32 Sodium metavanadate A-33 Lanthanum chloride A-34 Lanthanum nitrate A-35 Lanthanum sulfate The above-mentioned metal compounds according to the present invention may be used alone or in combination, and the amount used is based on the organic acid iron chelate complex. It is preferable that the amount is 1/2 mole or more, and it is especially preferable to use an equimolar amount or more. In the present invention, water-soluble silver salts are those produced as a result of continuous treatment in a bath for desilvering during processing of silver halide photographic materials, and examples of these soluble silver salts include silver thiosulfate complex salts and silver halide complex salts. , thioether silver complex salt, thiocyanate silver complex salt,
Examples include ammonia silver complex salt and silver acetate. The organic acid iron chelate complex according to the present invention has the function of oxidizing metallic silver generated by development and converting it into silver halide, and at the same time coloring the uncolored areas of the color former, and its structure is made of aminopolymer. Iron or metal ions are coordinated with carboxylic acid or an organic acid such as polycarboxylic acid such as oxalic acid or citric acid.
The most preferred organic acid used to form such an organic acid iron chelate complex is, for example, a polycarboxylic acid or an aminopolycarboxylic acid represented by the following general formula [] or []. General formula [] HOCO−A ₁ −Z−A ₂ −COOH General formula [] [In each general formula, A ₁ , A ₂ , A ₃ , A ₄ , A ₅ and
A ₆ is a substituted or unsubstituted hydrocarbon group, respectively;
Z represents a hydrocarbon group or N-A ₇ (A ₇ is a hydrocarbon group or a lower aliphatic carboxylic acid). ] These polycarboxylic acids or aminopolycarboxylic acids may be alkali metal salts, ammonium salts, or water-soluble amine salts. Representative examples of the aminopolycarboxylic acid or polycarboxylic acid represented by the general formula [] or [] include the following. (1) Ethylenediaminetetraacetic acid (2) Diethylenetriaminebentaacetic acid (3) Ethylenediamine-N-(β-oxyethyl)-N,N',N'-triacetic acid Propylenediaminetetraacetic acid (4) Nitrilotriacetic acid (5) Cyclohexanediaminetetraacetic acid Acetic acid (6) Iminodiacetic acid (7) Dihydroxyethylglycine (8) Ethyl ether diamine tetraacetic acid (9) Glycol ether diamine tetraacetic acid (10) Ethylene diamine tetrapropionic acid (11) Phenyl diamine tetra acetic acid (12) Ethylene diamine tetra acetic acid di Sodium salt (13) Ethylenediaminetetraacetic acid tetra(trimethylammonium) salt (14) Ethylenediaminetetraacetic acid tetrasodium salt (15) Diethylenetriaminepentaacetic acid pentasodium salt (16) Ethylenediamine-N-(β-oxyethyl)-N,N', N′-Triacetic acid sodium salt (17) Propyleneaminetetraacetic acid sodium salt (18) Nitrilotriacetic acid sodium salt (19) Cyclohexanediaminetetraacetic acid sodium salt (20) Citric acid (21) Oxalic acid (22) Maleic acid (23) Tartaric acid (24) Succinic acid (25) Sulfamic acid (26) Phthalic acid (27) Gluconic acid The effect of the present invention is that the above-mentioned organic acid iron chelate complex causes a metal nuclear exchange reaction with the above-mentioned metal compound to exchange iron with iron. This method focuses on the fact that silver can exchange with other metals to form an organic acid-metal chelate complex that is inert to silver.This inert complex prevents silver from being redissolved during recovery. It is characterized by the fact that silver recovery efficiency is improved by avoiding this. If a chelating agent is present as a receptor for the iron ions released as described above, the released iron ions will not precipitate as hydroxide, and the metal exchange reaction will proceed more smoothly. Therefore, in the present invention, it is preferable to use a chelating agent in combination. Specific examples of the chelating agent preferably used in the present invention include the following compounds, but are not limited thereto. (Exemplary compounds) B-1 1-hydroxyethylidene-1,1-diphosphonic acid B-2 2-phosphonobutane-1,2,4-tricarboxylic acid B-3 Sodium hexametaphosphate B-4 Sodium pyrophosphate B-5 Tripolyphosphoric acid Sodium B-6 1-hydroxy-1,1-diphosphonopropane-3-carboxylic acid B-7 1-hydroxy-1-phosphonoethane-
1-Carboxylic acid B-8 1-hydroxy-1-phosphono-propane-1,2,3-tricarboxylic acid B-9 Potassium 1,1-diphosphonoethane-2-carboxylate B-10 Sodium gluconate B-11 Di( hydroxyethyl)glycine B-12 Triethanolamine B-13 2-phosphonopentane-2,5-dicarboxylic acid B-14 Hydroxyethyliminodiacetic acid B-15 Sodium diethylenetriaminepentaacetate When the above chelating agent is not added at all Although it is possible to obtain the effects of the present invention, a more preferable effect can be obtained by adding the iron ions to an extent that does not precipitate the iron ions released in the metal substitution reaction. Further, the photographic processing solution to which the metal compound according to the present invention is added is used in a pH range of 2 to 11, preferably in a pH range of 5 to 8. The silver recovery method, conditions, etc. of the photographic processing solution to which the metal compound has been added vary depending on the composition of the processing solution and the equipment used, but are preferably determined in advance in accordance with these factors. Next, in order to show the liquid to which the present invention is applied, preferred processing steps used for processing photographic materials will be described, but the invention is not limited thereto. Color development phenomenon - Bleaching - Water washing - Fixing - Water washing - Stable Color development phenomenon - Bleaching - Pre-washing - Fixing - Water washing - Stable Color development phenomenon - Bleaching - Pre-washing - Fixing - Pre-washing - Water washing - Stable Color development phenomenon - Bleaching - Fixing - Pre-washing - Washing - Stable Color development - Bleach-fixing - Washing - Stable Color development - Bleach-fixing - Pre-washing - Washing - Stable First phenomenon - Washing - Reversal - Color development - Bleach adjustment - Bleach - Fixing - Washing - Stable First phenomenon - Washing - Reversal - Color development phenomenon - Bleach adjustment - Bleach - Fixing - Pre-washing - Washing - Stable First phenomenon - Washing - Reversal - Color development phenomenon - Bleach adjustment - Bleach-fixing - Pre-washing - Washing - Stable First phenomenon - Stopping - Washing - Reversal color development phenomenon - Stopping - Water washing - Bleaching - Bleach neutralization - Fixing - Water washing - Stability Silver halide photographic materials such as color negative film, color paper, and color reversal film are developed through these processing steps, but the present invention The method can be applied to any treatment liquid containing an organic acid iron chelate complex and a soluble silver salt in each of the above steps. Furthermore, the following method may be mentioned as a preferred embodiment of the present invention, but is not limited thereto. For example, the overflow liquid discharged from a bleach-fix bath, a fix bath, a subsequent washing bath or an intermediate bath containing a soluble silver salt and an organic acid iron chelate complex is collected in a storage container, and the metal compound according to the present invention is contained therein. Silver can be recovered efficiently. Further, two or more overflow liquids from each of the baths as described above can be mixed and stored in a storage container, and the metal compound can be added thereto to recover silver. Furthermore, in the case of a fixing bath, it is also possible to add the above-mentioned metal compound to the overflow liquid, recover the silver, correct the components consumed in the processing process, and reuse it. Alternatively, the metal compound described above may be added to the replenisher solution of the fixing bath or intermediate bath, and the overflow solution may be mixed with one or more of the above solutions and stored in a storage container for silver recovery. Furthermore, in the method of adding the metal compound to the replenisher, it is also possible to connect the fixing bath and the silver recovery device and recover silver during continuous processing. It can also be applied to a method for recovering silver from a bleach-fix solution using electrodialysis as disclosed in Japanese Patent Application Laid-Open No. 53-60371. In other words, the concentrated solution containing thiosulfate and soluble silver salt obtained by electrodialysis may contain a microdialyzed organic acid iron chelate complex such as ethylenediaminetetraacetic acid, which is a bleaching component of the bleach-fix solution. When silver is recovered from such a solution by electrolysis, by allowing the metal compound of the present invention to be present, silver can be recovered more efficiently. The silver recovery method of the present invention can be applied to any liquid, not only a photographic liquid, as long as it contains the above-described soluble silver salt and organic acid iron chelate complex. According to the present invention, all of the above objects of the present invention can be achieved, and the remarkable effects of the present invention are listed as follows. (1) Silver can be recovered without reducing recovery efficiency when a solution containing a soluble silver salt and an organic acid iron chelate complex is used in a commonly used silver recovery device for fixing solutions or bleach-fixing solutions. (2) The decomposition of sulfite that occurs during silver recovery can be prevented. (3) The fixer containing the organic acid iron chelate complex can be reused. Hereinafter, the details of the present invention will be explained with reference to Examples, but the embodiments of the present invention are not limited thereto. [Example 1] Sakura color film (Konishi Roku Photo Industry Co., Ltd.)
Konica FS-1 camera (manufactured by Konishiroku Photo Industry Co., Ltd.)
After photographing using the H4 hanging automatic processor
-72S (manufactured by Noritsu Koki Co., Ltd.) was modified and continuous processing was performed according to the following steps. Treatment process (38℃) Processing time Replenishment amount [ml/135/20, 1 bottle] Color development 3 minutes 15 seconds 48 Bleaching 6 minutes 30 seconds 58 Fixing 6 minutes 30 seconds 36 Washing 3 minutes 15 seconds 3000 Stability 1 minute 30 seconds 36 Among the above processing solutions, except for the bleaching solution and the fixing solution, CNK-4 processing solution (manufactured by Konishiroku Photo Industry Co., Ltd.) was used. Next, the compositions of the bleaching solution and fixing solution used are shown. [Bleach bath solution] Ethylenediaminetetraacetic acid iron ammonium salt Ethylenediaminetetraacetic acid diammonium chloride Ammonium bromide solution is added to bring the solution to 1, and the pH is adjusted to 6.00 using aqueous ammonia or glacial acetic acid. 100g 10g 150g [Bleach replenisher] Ethylenediaminetetraacetic acid iron ammonium salt Ethylenediaminetetraacetic acid iron diammonium chloride Add ammonium bromide water to make 1, and adjust the pH to 5.70 using aqueous ammonia or glacial acetic acid. 118g 11.8g 177g [Fixing bath solution] Add ammonium thiosulfate anhydrous sodium sulfite and sodium metabisulfite water to make 1, and adjust to PH 6.50 using acetic acid and 25% aqueous ammonia. 175g 8.6g 2.3g [Fixer replenisher] Ammonium thiosulfate Anhydrous sodium sulfite Sodium metabisulfite Add water to make 1, and adjust to PH6.45 using acetic acid and 25% sodium hydroxide. 206g 10.1g 2.7g The processing method was continuous processing according to the CNK-4 processing manual [Konishiroku Photo Industry Co., Ltd.]. At this time, the silver concentration of the overflow liquid discharged from the fixing bath was 6 g/g/. Further, the amount of iron that was carried into the fixing bath from the bleaching bath and accumulated was 1.8 g/min. When 40% of the overflow liquid discharged from the fixing bath was accumulated in the storage container, it was transferred to an electrolytic cell of an electrolytic silver recovery device for fixing liquid SR-50 (manufactured by Sun Seiki Seisakusho Co., Ltd.) and electrolyzed. This was used as a comparative example for this experiment. On the other hand, as an example of the present invention, exemplified compounds A-3, A-8, A-9, A-
19, A-22, A-31, and A-33 per 1 mol of the above-mentioned overflow liquid (equivalent to about 1.6 times the mol of the organic acid iron chelate complex accumulated in the fixer).
and Exemplified Compound B-2 (20 g/min) were added thereto, and the mixture was transferred to a fixing electrolytic cell and electrolyzed in the same manner as in the comparative example described above. Electrolysis conditions are cathode rotation speed 180r.pm and current 15A.
flowed. After electrolyzing for 5 hours under these conditions, the remaining silver amount, remaining sulfite amount, and pH of the solution were analyzed. The above results are shown in Table-1.

【table】

[Example 2]

Exemplified compounds A-3, A-8, A- in Example-1
9 and A-31 were added and the silver concentration after silver recovery was 0.5.
The above-mentioned exemplified compounds A-3, A-8, A-9, A-31 and A-33 were added to each fixer whose concentration was below
After adding 0.08 mol/each of 0.08 mole/ammonium thiosulfate and anhydrous sodium sulfite to make up for the shortage, the pH was adjusted to 6.45 using acetic acid and 25% aqueous ammonia to obtain a regenerated replenisher. Using this regenerated replenisher, continuous treatment was carried out in the same manner as in Example-1, and this was repeated 10 times, and the same results as in Example-1 were obtained. Furthermore, no abnormality occurred in the photosensitivity characteristics. [Example 3] Exemplary compound B-2 according to the present invention added to the fixing bath overflow liquid in Example-1 was replaced with Exemplary compound B
When the same experiment as in Example-1 was carried out by replacing B-1, B-3, B-7 and B-15, the same results as in Example-1 were obtained. [Example 4] When the same experiment as in Example 1 was conducted without adding the exemplified compound B-2 according to the present invention that was added to the fixing bath overflow liquid in Example 1, it was found that the precipitation of iron hydroxide was However, the same results as in Example-1 were obtained. [Example 5] The amount of the exemplified compound A-9 of the present invention added to the fixing bath overflow liquid in Example-1 was added to the organic acid iron chelate complex (specifically, ethylenediaminetetraacetic acid iron salt) accumulated in the fixing bath. The same experiment as in Example 1 was carried out by changing the amount of 0 times mole, 0.2 times mole, 0.5 times mole, 1.0 times mole, 1.6 times mole, and 3.0 times mole of ). The results are shown in Table 2 below.

[Example 6]

Electrolytic silver recovery device for fixer in Example-1 SR-50
Metal substitution method silver recovery equipment Sakura Repro Unit 1
Silver was recovered using a mold (manufactured by Sakuralipro Co., Ltd.) at a flow rate of 250 ml/min. The metal used for metal replacement in this device is iron (wool-like). After passing the liquid continuously for 40 hours, the residual silver concentration in the passed liquid was measured and the shape of the cartridge of the passed liquid, such as clogging, was observed. The results are shown in Table-3.

【table】

【table】

[Table] As is clear from the above table, by adding the metal compound of the present invention, silver can be efficiently recovered without clogging the cartridge.

Claims (1)

[Claims] 1. In a method for recovering metallic silver from a photographic processing solution containing an organic acid iron chelate complex and a water-soluble silver salt, a stable organic acid metal chelate complex is formed by performing a metal core exchange reaction with the organic acid iron chelate complex. 1. A method for recovering silver, characterized in that a metal compound capable of producing silver is present in the photographic processing solution in an amount of 0.2 times or more the mole of the organic acid iron chelate complex.