JP2706134B2 - Silver recovery method for photographic processing solution - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for recovering silver from a photographic processing solution. In particular, silver which can be electrolytically desilvered from the used processing solution containing silver halide to recover silver, or which can recover silver and reuse this processing solution without any problem in photographic performance Regarding the collection method.

[Prior Art] In order to obtain an image by exposing and processing a silver halide photographic light-sensitive material, development and fixing steps are provided. For example, for a color photographic light-sensitive material, color development, bleaching, fixing, and stabilization processing are performed. Or a bleach-fixing step in which bleaching and fixing are performed in one step.

In this fixing or bleach-fixing step, silver complex ions in the photographic light-sensitive material are dissolved by a silver halide solubilizing agent such as thiosulfate and thiocyanate. Significant accumulation.

In other steps, a silver halide solubilizing agent such as a sulfite ion or a thiocyanate ion is added as in the fixing and bleach-fixing steps as in the developing step, or these silver complex ions are photographed. The silver complex ions accumulate with the progress of the processing although they are less than in the fixing step because they are contained or adhered into the photographic material and flow in.

Such accumulation of silver complex ions significantly reduces the capacity of the processing solution, and poses a serious problem in terms of pollution control when the processing solution is discarded. Therefore, from the viewpoint of the recovery of the processing liquid capacity, the reduction of pollution at the time of disposal, and the recovery and reuse of useful resources,
It is desired to recover silver complex ions in the processing solution.

Further, from the viewpoint of pollution prevention and effective use of resources, the supply of replenisher to the processing tank in order to prevent the performance from deteriorating during continuous processing of the photographic light-sensitive material should be reduced, that is, replenished per unit area. There is a tendency to supply the solution as little as possible, which causes excessive accumulation of silver ion concentration.

Therefore, maintaining the silver ion concentration in the processing premises at a low concentration while continuously recovering silver ions is carried out in order to promote the reaction efficiently or adhered to the photographic material for the next processing step. It is also highly desired to prevent the resulting silver spill. Similarly, it is also strongly desired to regenerate the solution after recovering the silver ion concentration and use it again as a replenisher from the viewpoint of preventing pollution and reusing resources.

Techniques of desilvering from such a processing solution include metal replacement methods using steel wool or aluminum wool using ionization tendency, sulfide precipitation method under alkaline conditions, reduction precipitation method using hydrosulfite, ion exchange, An ion exchange method using a resin or a chelate resin and an electrolytic reduction method using electrolysis are known.

[Problems to be Solved by the Invention] In the metal replacement method, silver or aluminum is eluted and hydroxide precipitates, so that the processing solution cannot be reused. The silver sulfide precipitation method and the reduction precipitation method are also used. The size of the apparatus is large because filtration is troublesome for the recovery of the silver precipitate, and the cost of the apparatus and operation are increased because a filter is required. Furthermore, since the characteristics of the processing liquid change, it is extremely difficult to reuse the processing liquid.

In the method using an ion exchange resin or the like, the ion exchange resin is expensive and the silver complex salt adsorption capacity of the resin is extremely small, which is not economically viable. Furthermore, since the ion-exchange resin adsorbed with the silver complex salt cannot be regenerated and is incinerated and treated, it is necessary to refill the ion-exchange resin, which also increases the equipment cost and operation cost. .

By the way, the electrolysis method itself has been known for a long time, and many examples of these prior arts can be found in, for example, a review by Emuel and Schreiber (J. of the SMPTE, page 74.505, 1965).

In particular, as a device of the electrode plate for the purpose of improving the current efficiency, U.S. Patent Nos. 405403, 2292314, 2158410, 384
0455, 400056, 4054503, German Patent DP-1093561, DT-
2507123, DT-2729567, 674988, 1176373, French patent 8148383, Italy patent (Ital.P.) 439945, 421922,
U.S. Pat.
306, 3072557, 1900893, 303942, 195953, 186670
1. As the control of current density and the like during electrolysis, there are many devices such as U.S. Patent No. 2110930, German Patent Nos. 712003, 1133565, and 1187806.

Furthermore, as an efficient silver recovery method from the bleach-fix solution,
JP-A-48-18191, U.S. Pat.No. 4037715, German Patent No.252814, and as a method for separating a cathode and the like by a diaphragm during electrolysis, German Patent Nos. 2607043 and 2532018, Japanese Patent Application Laid-Open No. 52-2631
5, JP-A-52-102724, JP-A-53-35534, JP-B-43-30167
The automatic control method by current control is described in detail in U.S. Pat. Nos. 3,872,032, 3,925,184 and 4,607,71, JP-A-53-32869, JP-A-52-115723, and French Patent 2,275,570. The method described in JP-A-52-72227 can be used in combination with the processing solution regeneration method.

By the way, the specific problem of silver recovery by electrolysis is that the ratio (current efficiency) of silver used for electrolysis with respect to the total current under the condition where silver is deposited is quite low, and the total current (density) is also low. The actual silver recovery rate is surprisingly low because it is not much greater than the electrolytic cell relationship. The increase in the iron (II) silver aminopolycarboxylate produced in this manner not only lowers the oxidation-reduction potential of the processing solution but also lowers the silver bleaching (oxidation) rate, as well as the image of color photographs. This causes a serious problem of causing reduction or leuco-formation of the color-forming dye which forms, thereby browning the dye.

At the anode, the color developing agent and sulfite are oxidized,
A problem arises in that tar and sulfate accumulate due to the oxide polymer.

In order to prevent such a problem as much as possible, conventionally, a method of reducing the current density has been devised by a rotating cathode plate system using high-speed rotation or a carbon fiber, and the device has been actually used.

However, despite these methods and many of the above-mentioned contrivances, in each case, the concentration of silver ions in the processing solution is sufficiently reduced, and at a low current density in order to eliminate processing problems, Extremely long electrolysis time is required, or problems such as formation of silver oxide and formation of sludge due to excessive accumulation of sulfate ions caused by oxidation of sulfite,
Although silver recovery is practically used in discarded processing solutions, it has been considered difficult to reuse silver because it causes the above-mentioned problems and seriously hinders photographic light-sensitive materials.

In recent years, development processing apparatuses have been downsized due to the dispersion of color photographic light-sensitive material processing.However, these processing methods have been combined with the dissolution of bleach-fixing processing in one bath and the simplification and speed of processing. The direction of reducing the amount of waste liquid by lowering the concentration of the processing solution has been further strengthened, and there is currently a concern that the influence of the accumulation of silver complex ions on the processing capacity will be further increased.

Therefore, the advantages of the electrolytic method as described above can be obtained, and the silver complex ion concentration can be reduced in a short period of time, and even if it is continuously processed, it can be reduced to the concentration required for photographic processing or pollution control, In particular, there is a strong demand for a silver recovery method and apparatus capable of recovering a trace amount of a silver component of about 0 to 100 ppm with high efficiency and a high recovery rate.

The present invention has been made in view of the above point, and a first object of the present invention is to enable silver to be recovered from a processing solution containing silver halide at a high efficiency and a high recovery rate by an electrolytic method. In providing technology.

A second object of the present invention is to provide an economical technology that can recover silver from a large amount of photographic processing solution in a short time at a small size and at low cost.

A third object is to provide a technique which has sufficient durability and can stably recover silver to a low silver concentration over a long period of time.

[Means for Solving the Problems] The inventors of the present invention have conducted many studies to achieve the above-mentioned object.
As a result of repeated experiments, in a method for recovering silver of a photographic processing solution in which a processing solution of a silver halide photographic light-sensitive material containing at least silver complex ions is subjected to electrolytic treatment and desilvering, a positive treatment was carried out in a processing solution containing silver halide. An electrode structure material in which a metal material that does not elute even when polarized is brought into contact with the anode side of the carbon material, or a bipolar type fixed bed electrolysis comprising an electrode structure material using a carbon material in which at least the anode part is coated with a metal material It has been found that this can be achieved by using a bath.

Further, a silver recovery apparatus for a photographic processing solution for subjecting a processing solution of a silver halide photographic light-sensitive material to electrolytic treatment and desilvering, which is used in this method, does not elute even if it is positively polarized in a processing solution containing silver halide. By providing an electrode structure material in which a metal material is contacted on the anode side of a carbon material, or a bipolar type fixed bed electrolytic cell composed of an electrode structure material using a carbon material in which at least the anode portion is coated with the metal material It has been found that the above object can be achieved.

In particular, by using a metal material for the anode portion of the bipolar electrode structure material, the carbon-based material itself of the electrode structure material can prevent the phenomenon of so-called burning of carbon due to anodic polarization and generation of oxygen. It has been found that corrosion of a carbon-based material can be suppressed and durability can be improved.

In the present invention, as the carbon-based material of the bipolar fixed-bed electrolytic cell, one that does not corrode with a processing solution containing silver halide is used. For example, a carbon material, a carbon-based composite material,
Graphite materials and carbon fiber woven fabrics are preferably used. The carbon material includes, for example, activated carbon, and the carbon-based composite material includes, for example, a material obtained by mixing graphite powder and copper powder, press-molding and firing. The graphite material is a commonly used porous graphite or felt graphite, and the electrode has a different degree of polarization when electrolyzed due to the difference between these materials, and the electrolysis voltage becomes large or small.

In the present invention, the electrode structure material of the bipolar fixed bed electrolytic cell is preferably a material having a plate-like structure through which a processing liquid can flow,
For example, a honeycomb structure, a perforated plate structure, a fibrous structure, a cotton-like structure, and a granular structure are preferably used. This bipolar fixed-bed electrolytic cell can prevent clogging if the porosity in the cross-sectional direction of the electrode with respect to the flow path of the processing liquid is 30% or more, and can also make the flow turbulent and improve the collection efficiency. This is preferable because it can improve the electrolysis voltage and can further reduce the electrolysis voltage.

In the electrolytic structural material of the present invention, a metal material that does not elute even when anodic polarized in a processing solution containing silver halide is in contact with the anode side of the carbon-based material, and this metal material and the carbon material are pressed and adhered. Alternatively, they may be fixed and in contact with each other, as long as currents flow between them. Further, stainless steel, titanium, a white metal, a white metal oxide, or the like is used as a metal material that does not elute even when anodic polarized in a processing solution containing silver halide.

Further, in the present invention, the surface of the carbon-based material or the metal material that comes into contact with the carbon-based material is coated with a metal catalyst that reduces the oxygen generation overvoltage. This allows
With a metal catalyst, the electrolysis reaction is promoted by lowering the electrolysis voltage, and oxygen is not generated on electrode materials such as carbon materials, carbon-based composite materials, graphite materials, and carbon fiber woven fabrics. However, the combustion of carbon does not occur and the life can be extended.

As the metal catalyst, a white metal such as Pt, Ru, Pd, and Ir can be used alone or in combination with RuO ₂ and IrO ₂ , or a white metal oxide can be used.

There are various methods for coating the metal catalyst, and generally, electrolytic plating is performed using an electrode material such as a carbon material, a carbon-based composite material, a graphite material, or a carbon fiber woven fabric as a cathode. In addition, an aqueous solution of a noble metal salt is applied to the electrode material, and then the noble metal oxide is coated by firing. Further, an aqueous solution of a noble metal salt is applied to a carbon-based material or a metal material, and then an aqueous solution of a reducing agent is applied to reduce and plate the noble metal. The effect of these metal catalyst coating methods on the electrolytic reaction is as long as the noble metal is firmly attached to the electrode material such as carbon material, carbon-based composite material and graphite material, carbon fiber woven fabric, etc.
They are almost equivalent. Further, a powder of a metal material may be sprayed on the anode side of the carbon-based material.

In the present invention, the distance between adjacent positive and negative electrodes of the bipolar fixed bed electrolytic cell is set to be equal to or less than the thickness of the electrode structural material,
The thickness is preferably 5 to 5 mm, more preferably 0 to 3 mm, and furthermore, the thickness of the electrode is 0.5 to 50 mm, from the viewpoint of improving the silver recovery speed and miniaturizing the apparatus, but is not particularly limited.

In the present invention, when the silver concentration in the silver halide-containing processing solution to be recovered is 500 mg / volume or less, no silver is generated in a dendrite shape on the electrode. For this reason, the phenomenon that the deposited silver breaks through the non-conductive spacer in the electrolytic cell, short-circuits the fixed bed electrodes, and causes precipitation of silver is unlikely to occur, and therefore, the silver recovery capacity in the electrolytic cell is improved. And preferred.

In the present invention, in the bipolar fixed-bed electrolytic cell, it is preferable to set the electrolytic current concentration to a large value of 50 Amp / or more in order to recover a small concentration of silver with high efficiency and high recovery rate.

This electrolysis current concentration is expressed by electrolysis current concentration = electrolysis current value / electrolysis cell volume. By setting this electrolysis current concentration to a large value of 50 Amp / or more, a high voltage is applied to promote polarization. It is possible to recover a trace concentration of silver with high efficiency and a high recovery rate.

In the present invention, it is preferable to provide an electrically insulating spacer having an opening between the electrodes in order to prevent a short circuit between the positive and negative electrodes. The spacer is preferably, for example, mesh-like or thread-like, and the number of the spacers is not particularly limited. However, the flow rate of the processing liquid must be 30% or more in the cross-sectional direction with respect to the processing liquid flow path of the spacer. Smooth and preferred.

In the present invention, the bipolar fixed-bed electrolytic cell is a LH
The SV value is preferably 1 [1 / HR] or less, and the LHSV value is represented by LHSV value = photo processing solution flow rate / electrolyzer volume. Thereby, the flow rate of the processing solution flowing through the bipolar fixed-bed electrolytic cell can be set to be small, and there is an effect that the trace concentration silver is completely recovered.

Such a bipolar fixed-bed electrolytic cell may be directly connected to the processing tank to electrolyze the overflow solution or to continuously process and regenerate the processing solution.

In the case of reusing the bleach-fix processing solution, the removal of suspended matter and the recovery of unnecessary ions can be carried out preferably by a filter tank and / or an ion-exchange resin tank following the bipolar fixed-bed electrolytic cell.

[Operation] In the present invention, when a processing solution containing a trace amount of a silver component is electrolyzed in a bipolar fixed-bed electrolytic cell, the electrode area is extremely increased with respect to the volume of the processing solution as compared with the conventional electrolysis method. In addition, an extremely high electric field is applied in the bipolar fixed-bed electrolytic cell, and the silver ion concentration gradient near the bulk layer and the electrode is eliminated as compared with the conventional electrolytic method. The concentration can be reduced.

Further, since the electrode can be prevented from being decomposed due to the generation of oxygen due to the anodic polarization, the life of the electrode is prolonged, and highly efficient and high-recovery silver recovery is realized.

[Effects of the Invention] The method for recovering silver of a photographic processing solution according to the present invention is characterized in that the processing solution of a silver halide photographic light-sensitive material containing at least silver complex ions is subjected to electrolytic treatment in a bipolar type fixed-bed electrolytic cell. In contrast, compared with the conventional electrolysis method, the electrode area is greatly increased, and an extremely high electric field is applied, so that silver recovery with high efficiency and high recovery rate can be performed compared with the conventional electrolysis method. Can be.

Further, with the configuration of the electrode structure material of the present invention, the life of the electrode is extended, and a long-lasting silver can be recovered.

Further, in the present invention, when a carbon material, a carbon-based composite material, a graphite material, a carbon fiber woven fabric, or the like is used as the electrode material of the bipolar fixed-bed electrolytic cell, the electrode can be prevented from being attacked by the treatment liquid. preferable. In the present invention,
The electrode structure material of the bipolar-type fixed-bed electrolytic cell is a material in which a treatment liquid can be distributed in a plate-like structure.For example, when a honeycomb structure, a perforated plate structure, a fibrous structure, a cotton-like structure, and a granular structure are used, It is preferable that the treatment liquid flows smoothly between the electrodes.

Further, in the present invention, it is preferable that the distance between adjacent positive and negative electrodes of the bipolar-type fixed-bed electrolytic cell be equal to or less than the electrode structural material, because the silver recovery speed is improved and the apparatus is downsized.

Further, in the present invention, the anode portion of the carbon-based material, the metal material is coated with a metal catalyst, and when the metal catalyst is a white metal, a white metal oxide, while promoting the electrolytic reaction, the carbon material, The life of carbon-based composite materials, graphite materials, carbon fiber mats and the like can be extended.

[Example] Hereinafter, an example of the present invention will be described.

The drawings are used to illustrate the invention and do not limit the invention.

Continuous replenishment was performed until the silver concentration in the fixing solution reached 6 g /.

[Experimental processing] Processing step Processing time Processing temperature Color development (1 tank) 3 minutes 15 seconds 38 ° C Bleaching (1 tank) 50 seconds 35 ° C Fixed (2 tanks) 1 minute 30 seconds 35 ° C (2 tank cascade) Stabilization 1 minute 35 ° C (cascade of 3 tanks) Drying 45 seconds 40-80 ° C The composition of the processing solution used is as follows.

[Color developing solution] potassium carbonate 30 g sodium hydrogen carbonate 2.5 g potassium sulfite 4 g sodium bromide 1.3 g potassium iodide 1.0 mg hydroxyamine sulfate 2.5 g sodium chloride 0.6 g 4-amino-3-methyl-N-ethyl-N- (Β-hydroxylethyl) aniline sulfate 4.8 g Potassium hydroxide 1.2 g Add water to make 1 and adjust to pH 10.06 with potassium hydroxide or 50% sulfuric acid.

[Color developing replenisher] potassium carbonate 40 g sodium hydrogen carbonate 3 g potassium sulfite 7 g sodium bromide 0.5 g hydroxylamine sulfate 3.1 g 4-amino-3-methyl-N-ethyl-N- (β-hydroxyethyl) aniline sulfate 6.0 g Potassium hydroxide 2 g Add water to make 1 and adjust to pH 10.12 with potassium hydroxide or 20% sulfuric acid.

[Bleaching solution] 1.3 Ferric ammonium salt of diaminopropane-N, N, N ', N',-tetraacetic acid 0.23 mol Ethylenediamine-N, N, N ', N',-ferric ammonium salt of tetraacetic acid 0.25 mol Hydroxyethylendiamine triacetic acid 10 g Ammonium bromide 150 g Glacial acetic acid 30 ml Ammonium nitrate 30 g Add water to make 1 and adjust the pH to 5.3 using ammonium water or glacial acetic acid.

[Bleaching replenisher] Ferric ammonium 1,3 diaminopropane-N, N, N ', N',-tetraacetic acid 0.33 mol Ethylenediamine-N, N, N ', N',-ferric ammonium tetratetraacetate Salt 0.36 mol Hydroxyethylethylenediamine triacetic acid 2 g Ammonium bromide 178 g Glacial acetic acid 21 ml Ammonium nitrate 35 g Add water to 1 and adjust the pH to 5.0 using ammonium water or glacial acetic acid.

[Fixing solution] Ammonium thiosulfate 200 g Ammonium sulfite 20 g Ethylenediaminetetraacetic acid 0.5 g Ammonium thiocyanate 160 g Add water to 1 to adjust the pH to 1 using acetic acid and aqueous ammonia.
Adjust to 7.0.

[Fixing replenisher] Ammonium thiosulfate 200 g Ammonium sulfite 20 g Ethylenediaminetetraacetic acid 0.5 g Ammonium thiocyanate 160 g Water is added to 1 to adjust the pH to 7.0.

[Stabilizing solution and stabilizing replenishing solution] formaldehyde (37% solution) 2 ml 5-chloro-2-methyl-4-isothiazolin-3-one 0.05 g emulgen 810 1 ml sodium formaldehyde bisulfite adduct 2 g water With ammonium water and 50% sulfuric acid
The pH was adjusted to 7.0.

However, the running test was carried out using 650 ml of a color developing replenisher, 140 ml of a bleaching replenisher, 815 ml of a fixing replenisher, and 1,000 ml of a stabilizing replenisher per 1 m ² of the light-sensitive material.

At this time, after the silver concentration in the fixer became 6 g /, all the overflows of the processing waste liquid were collected, and 100% with tap water.
Diluted twice. The silver concentration at this time was 20 mg /. This solution was used to bleach Konica Color SR paper.
Continuous processing was performed until the amount became 4 g /. In this embodiment, this liquid is referred to as liquid A.

Processing process Temperature Time Replenishment amount (1) Color development 38 ° C 3 minutes 30 seconds 151ml / m ² (2) Bleaching and fixing 35 ° C 1 minute 30 seconds 160ml / m ² (3) Super stabilizer 33 ° C 2 minutes 00 seconds 250ml / m ² This is an overflow solution of the above processing solution, and 4 g of bleach-fixed silver
The solution that reached / was set aside, diluted 100 times with tap water, and then subjected to a silver recovery test. The silver concentration was 20 mg /
Met. This liquid is referred to as Liquid B.

[Color developing tank solution] Water was added to 800ml of potassium bromide 1.5g Potassium sulfite 2.0g hydroxylamine 3.0g benzyl alcohol 15g Kodak CD-3 5.0 g Potassium carbonate 25g water to 1, with KOH and H ₂ SO _4, the pH It was 10.2.

[Color developer replenisher] Water was added to 800ml hydroxylamine 3.5g benzyl alcohol 18g Kodak CD-3 6.0 g Potassium carbonate 25g water to 1, with KOH and H ₂ SO _4, and the pH was adjusted to 10.45.

[Bleaching / fixing tank solution and replenisher] Ammonium sulfite 12 g Ammonium thiosulfate 68 g Iron ammonium diaminetetraacetate dihydrate 60 g Ethylenediaminetetraacetic acid 2 g Add water to make 1 and adjust to pH 6 with ammonia vinegar and acetic acid.
7 was set.

[Super Stabilizer Tank Solution and Replenisher] 5-Chloro-2-methyl-4-isothiazolin 3-one 0.02 g 2-methyl-4-isothiazolin 3-one 0.02 g Ethylene glycol 1.0 g 2-octyl-4-isothiazoline-3 -One 0.01 g 1-hydroxyethylidene-1.1-diphosphonic acid (60%
Aqueous solution) and 1 3.0 g BiCl3 (45% aqueous _{solution) 0.65g MgSO 4 .7H 2 O 0.2g} 25% ammonia solution 2.5g water to a pH of 7.0 with ammonia water and H ₂ SO _4.

Commercially available Konica Color QA paper was continuously processed until the silver concentration of the bleach-fix solution became 4 g /.

Processing process Temperature Time Replenishment amount (1) Color development 35 ° C 45 seconds 162ml / m ² (2) Bleaching and fixing 35 ° C 45 seconds 216ml / m ² (3) Super stabilizer 30 ° C 90 seconds 247ml / m ² Overflow of the above processing solution Liquid, 4g of bleach-fixed silver
The solution that reached / was set aside, diluted 100 times with tap water, and then subjected to a silver recovery test. The silver concentration was 20 mg /
Met. This liquid is referred to as liquid C.

[Color developing tank solution] Water 800 ml Potassium bromide 2.0 g Potassium sulfite 0.1 g Diethylhydroxylamine 4.9 g Diethylenetriamine 3.0 g Kodak CD-3 5.0 g Potassium carbonate 25.0 g Add water to make 1; KOH and H ₂ SO ₄ The pH was set to 10.12.

[Color developing replenisher] Water 800 ml Potassium chloride 0.2 g Diethylhydroxylamine 5.3 g Kodak CD-3 5.8 g Potassium carbonate 24 g Water was added to adjust the pH to 1, and the pH was adjusted to 10.45 with KOH and H ₂ SO ₄ .

[Bleaching and fixing tank solution and replenisher] Ammonium sulfite 14 g Ammonium thiosulfate 70 g Iron ammonium diaminetetraacetate dihydrate 49 g Ethylenediaminetetraacetic acid 2 g Water was added to adjust the pH to 1, and the pH was adjusted to 5.5 with aqueous ammonia acetic acid.

[Super Stabilizer Tank Solution and Replenisher] 5-chloro-methyl-4-isothiazolin-3-one 0.02 g 2-methyl-4-isothiazolin-3-one 0.02 g ethylene glycol 1.0 g 2-octyl-4-isothiazoline-3 -One 0.01 g 1-hydroxyethylidene-1.1-diphosphonic acid (60%
Aqueous solution) and 1 3.0 g BiCl3 (45% aqueous _{solution) 0.65g MgSO 4 .7H 2 O 0.2g} 25% ammonia solution 2.5g water, with aqueous ammonia and H ₂ SO _4, the pH is 7.0.

FIGS. 1 to 3 show a photographic processing solution silver recovery apparatus according to the present invention. As shown in FIG. 1, the processing liquid flowing from the automatic developing apparatus is sent to a bipolar fixed-bed electrolytic cell 3 via a filter 2 by driving a pump 1. A rectifier connected to a commercial power supply is provided in this bipolar fixed-bed electrolytic cell 3.
A predetermined DC voltage is applied from 31 and silver is recovered in the bipolar fixed-bed electrolytic cell 3, and the processing liquid is discharged from the flow output and returned to the automatic developing device or discarded.

This double pole fixed bed electrolytic cell 3 is configured as shown in FIG. In the figure, reference numeral 4 denotes a vinyl chloride pipe having a diameter of 7 cm and a length of 15 cm, and seven electrode blocks 5 are stacked in the pipe 4 with a spacer 6 interposed therebetween. Have been.

The electrode block 5 has a diameter of 6.8 c as shown in FIG.
An electrode material having a thickness of 1 cm and a thickness of 1 cm is used. The spacer 6 is made of a 50 mesh PE net.

At both ends of the laminated electrode portion, a mesh-shaped DSE (dimension stuck electrode) anode 8 and a mesh-shaped titanium cathode 9 are provided as current-carrying electrodes.

When an experiment was performed using the solution A, the results shown in FIG. 4 were obtained. In this embodiment, the electrolytic current concentration is preferably 50 Amp / or more, as shown in FIG. The LHSV value is preferably 1 [1 / HR] or less as shown in FIG. Further, as shown in FIG. 6, the porosity of the electrode block 5 is 30%.
%, And the porosity of the spacer 6 is also preferably 30% or more, as shown in FIG. 8. Under these conditions, a high-efficiency and high-recovery-rate apparatus and operation can be performed. Similar results were obtained using the B and C solutions.

(Experiment 1) Using the solution A, the electrode material was the electrode block 5 of FIG. 3, and the electrode material shown in Table 1 was used.
The results of use are shown in Table 1. In the case where the carbon electrode exceeds 30 days, the value is obtained from the value until the reduced dry weight of the carbon electrode becomes the reduced weight until black carbon powder is output.

(Experiment 2) The same results as in Experiment 1 were obtained by using the solution B and the solution C.

(Experiment 3) Lining with liquid treated with Fuji.FRSS10 (Fujicolor rinse saving system) in place of A, B, and C liquids used in Experiments 1 and 2 and instead of super stabilizers. The liquids thus obtained are referred to as A ', B', and C ', respectively.
Using these liquids, the same results as in Table 1 were obtained.

(Experiment 4) Instead of the liquids A, B, and C used in Experiments 1 and 2, a small water washing in which the replenishment amount of the soot stabilizer was increased to about 100 times was used. At this time, dilution was not performed as if the liquids A to C were made.

These liquids are referred to as A "to C", respectively.
Similar results were obtained with the C ″ liquid.

The Ti mesh swells as it is electrolyzed,
The electrolytic cell has been scratched. Therefore, it is preferable to use a platinum mesh or an oxidized mesh because swelling does not occur.

(Experiment 5) Using the solution A, the electrode materials shown in Table 2 were used. The results of use are shown in Table 2. In addition, the values exceeding 30 days are values obtained from the dry weight at which the carbon electrode decreases as in Experiment 1.

(Experiment 6) The same results as in Experiment 8 were obtained by using the solution B and the solution C.

(Experiment 7) Instead of the A, B, and C solutions used in Experiments 5 and 6, and instead of the super stabilizer, use a solution treated with water treated with Fuji.FRSS10. ,
B 'and C'. Using these liquids, the same results as in Table 2 were obtained.

(Experiment 8) Instead of the solutions A, B, and C used in Experiments 5 and 6, a small flush with a replenishment amount of the super stabilizer increased to about 100 times was used. At this time, dilution was not performed as if the liquids A to C were made.

These liquids are referred to as A "to C", respectively.
Similar results were obtained with the C ″ liquid.

Note that by using a Ti material as a metal material and coating this metal material, the life of the electrode can be extended, and expensive platinum metal does not need to be used, and it is inexpensive.

(Experiment 9) Using the solution A, the electrode materials shown in Table 3 were used. The results of use are shown in Table-3. In addition, the values exceeding 30 days are values obtained from the dry weight value at which the carbon electrode decreases as in Experiment 1.

(Experiment 10) The same results as in Experiment 9 were obtained by using the solution B and the solution C.

(Experiment 11) The liquids treated with Fuji.FRSS10-treated water instead of the A, B, and C liquids used in Experiments 9 and 10 and the Super Stabilizer, , B ', C'. Using these liquids, Table-3
And similar results were obtained.

(Experiment 12) Instead of the solutions A, B, and C used in Experiments 9 and 10, a super stabilizer was used, and a small flush with a replenishing amount increased to about 100 times.
At this time, dilution was not performed as if the liquids A to C were made.

These liquids are referred to as A "to C", respectively.
Similar results were obtained with the C ″ liquid.

(Experiment 13) Using the solution A, the electrode materials shown in Table-4 were used. The results of use are shown in Table-4. In addition, the values exceeding 30 days are values obtained from the dry weight at which the carbon electrode decreases as in Experiment 1.

(Experiment 14) The same results as in Experiment 13 were obtained by using the solution B and the solution C.

(Experiment 15) In place of the A, B, and C solutions used in Experiments 13 and 14, and in place of the super stabilizer, water treated with Fuji.FRS810 was used. , B ', C'. Using these liquids, Table-4
And similar results were obtained.

(Experiment 16) Instead of the liquids A, B, and C used in Experiments 13 and 14, a small flush with a replenishment amount of the super stabilizer increased to about 100 times was used. At this time, dilution was not performed as if the liquids A to C were made.

These liquids are referred to as A "to C", respectively.
Similar results were obtained with the C ″ liquid.

As described above, by setting the distance between the electrodes to the range of the present invention, the effect of the present invention was successfully achieved.

(Experiment 17) Using the liquid B, the silver capacity of the silver recovery device was determined. The silver concentration was adjusted by adding silver nitrate. As a result, the lower the silver concentration, the higher the silver capacity and the less the generation of dendritic silver.

Similar results were obtained using liquids A, C, A ', B', C 'and A "to C". The results are shown in Table-5.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a silver recovery apparatus for a photographic processing solution, FIG. 2 is a diagram of a bipolar fixed-bed electrolytic cell, FIG. 3 is a perspective view of an electrode block, and FIG. FIG. 5 shows the relationship between the LHSV value and the silver recovery rate, FIG. 6 shows the relationship between the porosity of the electrode block and the electrolytic voltage, and FIG. It is a figure which shows the relationship between a porosity and electrolysis voltage. In the figure, reference numeral 1 denotes a pump, 2 denotes a filter, 3 denotes a bipolar fixed-bed electrolytic cell, 5 denotes an electrode block, and 6 denotes a spacer.

Claims (1)

(57) [Claims] In a method for recovering silver of a photographic processing solution, which comprises subjecting a photographic processing solution of a silver halide photographic light-sensitive material containing at least silver complex ions to electrolysis and desilvering, a silver halide photographic processing solution containing a silver halide ion is positively treated. An electrode structure material in which a metal material that does not elute even when polarized is brought into contact with the anode side of the carbon material, or a bipolar fixed bed composed of an electrode structure material using a carbon material in which at least the anode portion is coated with the metal material In the electrolytic cell, electrolytic treatment is performed to desilver, and the carbon-based material has a honeycomb structure using a carbon material, a carbon-based composite material and a graphite material, a perforated plate structure, a fibrous structure, a cotton-like structure, and a granular structure. , The metal material is stainless steel, titanium, white metal, white metal oxide, the electrode structure material,
A photographic processing solution characterized by having a plate-like structure through which a processing solution can flow, and a distance between adjacent anodes and cathodes of the bipolar fixed-bed electrolytic cell being equal to or less than an electrode structure material thickness. Silver recovery method.