JPS6045417B2 - Fixer regeneration method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention restores the fixing ability of a fixer whose fixing ability has been reduced (hereinafter referred to as a fatigued fixer) by processing a silver halide photographic light-sensitive material, and restores the initial fixing ability. The present invention relates to a method for regenerating a fixer using a composition for regenerating a fixer.

It is necessary to regenerate and reuse a fixer solution whose fixing ability has decreased in order to effectively utilize materials and to prevent pollution when a fixer solution with high B, O, and D values is disposed of.

The mechanism of action of photographic fixers is described in detail in "Photography Chemistry" by Shinichi Kikuchi, Kyoritsu Zensho, page 132.

The silver halide in the silver halide photographic light-sensitive material repeatedly reacts with the fixing agent during processing and gradually becomes a soluble silver complex salt that is eluted into the fixing solution, and this remains, reducing its fixing ability. Therefore, the first condition for restoring and regenerating the fixing ability is to recover the soluble silver salt dissolved in the fixing solution. The recovery methods include the silver precipitation method in which insoluble silver is precipitated using chemical reagents, the metal displacement method in which silver is precipitated by contacting it with a metal that has a higher ionization tendency than silver, and the metal substitution method in which silver is deposited on the cathode in an electrolytic cell. Electrolytic methods for precipitation are known, and these methods are described by M and L. Schrei Hani's "PresentS"
tatusofSilverRecoveryinMo
tionpictureLmbc)ratories”
entitled '“JournaloftheSMPTE''
, Vol. 74, pp. 505-513 (June 196). Among these various silver recovery methods, the method using chemical reagents is complicated and produces by-products, so it is fine if the purpose is only to recover silver, but it is not recommended to regenerate and reuse the fixer. This is not the preferred method if used.

In addition, the metal replacement method is easy to operate and can be operated continuously, but as silver is recovered, the metal is ionized and dissolved as iron ions and aluminum ions, so it requires continuous regeneration and drying. In some cases, the following undesirable phenomena occur.

That is, each time the regeneration is repeated, the metal ions in the solution become concentrated, and some of them must be discarded. It is undesirable to discharge this directly as it will cause secondary pollution.
Another drawback is that separate equipment is required to process this. Electrolysis is the most suitable silver recovery method when the purpose is not only to recover silver but also to further recover the ability of the fixing solution after silver recovery and to repeatedly and continuously regenerate it. be.

That is, according to the electrolysis method, undesirable problems can be avoided by checking and controlling the electrolysis conditions, such as the silver ion concentration contained in the fixer before and after electrolysis, the flow rate of the fixer, the electrolytic current, and the voltage. Silver can be recovered easily and continuously without producing by-products, and a regenerant can be added.

However, a drawback of using the electrolysis method is that the pH of the fixer solution after silver recovery may be lowered. Conventionally, silver is recovered using electrolysis, then regenerated by adding a regular fixer replenisher and recycled for use. This often results in not only a decrease in the concentration of fixing components, but also a significant decrease in pH, deteriorating fixing ability, and decomposition of thiosulfate. Therefore, with conventional methods, it is very difficult to continuously regenerate and reuse the fixer whose fixing ability has decreased as the photosensitive material is processed. Ta.

Furthermore, after silver is recovered from a fixing solution containing soluble silver complex salts eluted during processing of silver halide photographic materials, a considerable amount of halogen ions remain.

Among halogen ions, iodide ions in particular are fixed. It is well known that as the iodide ion content increases, the fixing speed decreases and fixing is significantly inhibited. Such iodine ions remain in large quantities in the fixing solution when a high-sensitivity photographic material consisting mainly of microcrystals of silver iodobromide is processed. Several methods have been proposed to remove such unnecessary iodine ions.
For example, this method is described in JP-A No. 49-562 Wani, JP-A No. 48-354, etc., but the method utilizes the reaction of polyalkylene oxide with iodide ions. The method described in Wani Publication No. 49-562 is a method in which polyalkylene oxide polymer is made into pellets and filled into a tube, and iodide ions are removed during the process of contacting with fatigue fixer. The method described in the Trowel Bulletin involves suspending relatively high-molecular polyethylene glycol in a semi-permeable membrane in a fatigue fixer to absorb iodide ions that diffuse through the semi-permeable membrane. This is method l. However, a disadvantage of such conventional methods is that the reactivity of the polyalkylene oxide with iodide ions is relatively low, making it time consuming and difficult to carry out regeneration continuously and automatically. In addition, the polyalkyleoxide partially eluted into the fixer during the contact process is foaming, so repeated regeneration of the fixer causes significant foaming of the regenerated fixer, which may impede silver recovery. In addition, such methods have the disadvantage of requiring special equipment for iodide ion removal. The amount of iodine ions eluted and remaining in the fixer varies depending on the type of photosensitive material and the amount of processing, but the amount of iodine ions converted into the amount of potassium iodide is large for color photosensitive materials. It is about 6 to 12y/'.

That is, although the new fixing solution does not contain any iodine ions, as the light-sensitive material is processed, the amount increases and gradually becomes saturated to reach the above-mentioned value. When the amount of such iodide ions increases, the fixing speed decreases, for example, 10y/e (calculated as potassium iodide).
7) When iodine ions are present in the fixer, the fixing speed decreases to about 113-114 compared to fresh solution. An object of the present invention is to provide a fixer regeneration method that can continuously regenerate a fixer without requiring any special equipment or reducing fixing ability. be.

Another object of the present invention is to provide a method for regenerating a fixer solution whose fixing ability has decreased due to processing of a photosensitive material by adding a regenerating composition to the fixer solution.

Another object of the present invention is to provide a regeneration method that does not cause decomposition of a fixer solution even if the fixer solution whose fixing ability has decreased is repeatedly regenerated. In order to achieve the above object, the present inventors have conducted various studies and found that in order to recover the fixing ability that has decreased due to the processing of photosensitive materials and to reuse the fixer, it is necessary to electrolyze the fixer. After recovering silver using the method, the fixer regeneration composition added to the fixer contains at least thiosulfate ions and sulfite ions, and has a pH of 7.0 to 10.5. Preferably 8.0 to 9.
5, in which the concentration of thiosulfate ions in the regenerated fixer is 150 f/e or more, preferably 17
5y/e or more, and the concentration of sulfite ions is 10y/e to 100q/e1, preferably 15y/' to 50y/e
It is quite surprising that the regenerated fixer exhibits the same fixing speed as the fresh fixer despite the presence of iodine ions, and even after repeated silver recovery, the regenerated fixer It has been found that there is no decrease in pH and no decomposition of thiosulfate ions occurs.

The present invention relates to this. The decrease in pH when silver is recovered from the fatigue fixer using electrolysis varies depending on the amount of silver recovered, but when 5 to 6y of silver is recovered per 1e of fatigue fixer. , the approximate pH value is 1.5
It decreases by 2 to 2 peaks.

The pH of a typical fixer that does not use an acid hardener is approximately 5.0.
7.0, so the pH of the fixer after silver recovery is 3.
The fixing ability decreases to 0 to 5.0 and the fixing ability deteriorates. According to the present invention, in order to prevent a decrease in the pH of the fixer solution from which silver is recovered, the pH of the regeneration composition is set to 7.5 to 10.5, preferably 8.0 to 9.5, and then the regeneration is performed. Even if silver recovery is repeated, the pH of the regenerated fixing solution does not decrease, so that the desired fixing ability can be maintained.

In addition, the concentration of thiosulfate ion in the regenerated fixer is 150
y/' or more, preferably 170y/e or more,
Regardless of the presence of iodide ions in the fixer, the fixing speed is similar to that of a new fixer that does not contain iodide ions. Further, in the present invention, in order to prevent a decrease in sulfite ions when silver recovery is repeated using an electrolysis method, sulfite ions are included in the regeneration composition in advance.

In this case, the amount of sulfite ions added is such that the concentration of sulfite ions in the regenerated fixer ranges from 10y/' to 100V/f1.
Preferably, in order to make it 15q/' to 50y/e, 50q/e to 300q/' is suitable, but of course the present invention is not limited to this, and the The concentration of sulfite ions is 10y/' to 100y
/', preferably from 15y/f to 50g/'. In addition, fatigue fixer (
The addition ratio of the regenerating composition to the regenerated fixer (running liquid) is generally 10:1 to 2:1, and the concentration of thiosulfate ions in the regenerated fixer is 150 y/e or more, preferably,
In order to maintain the concentration of 175 y/' or more, the object of the present invention can be achieved if the concentration of thiosulfate ions in the fixer regeneration composition is 400 v/e or more, preferably 500 y/e or more.

Of course, the present invention is not limited to this, and the concentration of thiosulfate ions in the regenerated fixer is 150y/' or more,
Preferably, it is sufficient to achieve 175q/f or more. The thiosulfate ion and sulfite ion used in the present invention are:
It is present when thiosulfate and sulfite or sulfite ion-releasing compounds are dissolved in solution; as thiosulfate ion,
Ammonium thiosulfate, sodium thiosulfate, and potassium thiosulfate; sulfites include ammonium sulfite, sodium sulfite, and potassium sulfite; and sulfite ion-releasing compounds include sodium metabisulfite, potassium metabisulfite, and ammonium metabisulfite. , and sulfite.

Further, in the present invention, various alkali and/or acid pH adjusters and chelating agents may be added to the fatigue fixer from which silver is recovered.

According to the present invention, even if the fatigued fixer is repeatedly regenerated, the fixing speed of the regenerated fixer does not decrease and exhibits the same fixing speed as the new fixer, and the It can be repeatedly regenerated semi-permanently without decomposition.

Further, in this case, no special device is required, and the fixer can be continuously and automatically regenerated. The present invention will be explained below with reference to the drawings.

FIG. 1 is a flow diagram showing a fixer regeneration system using a batch electrolytic silver recovery method.

The fatigue fixer that has reflowed from the processor 13 is stored in a storage tank 14 and sent to a regeneration tank 18 through a filter 16 by a transfer pump 15. The regeneration tank 18 is connected to a silver recovery device 17 using an electrolysis method by a circulation pump 15'', and recovers silver by circulating the fatigue fixer for a certain period of time.After silver recovery is completed, the fixer is recovered by the present invention. After adding the regeneration composition 19 to the recovered silver fatigue fixer, it is sent to the replenishment tank 11, and the replenishment device 12
The processor 13 is replenished through. FIG. 2 is a diagram showing a flow diagram of a constant flow type.

The fatigue fixer that has reflowed from the processor 23 is stored in a storage tank 24, and is automatically sent at a constant flow rate to a silver recovery device 27 using electrolysis through a filter 26 by a metering pump 25. After silver recovery, the fatigued fixer is sent to the storage tank 24'', and at the same time, the composition 29 for regenerating the fixer according to the present invention is automatically added, and then sent to the replenishment tank 21 by the transfer pump 25'' for replenishment. Device 2
2 to the processor 23. FIG. 3 is a diagram showing a flow diagram of the processor direct connection type. Processor 31 and electrolytic silver recovery device 34
The fatigue fixer that has reflowed from the processor 31 is sent to the silver recovery device 34 through the filter 33 and flowmeter 36 by the transfer pump 32, and silver is automatically recovered.

In this case, the regenerating fixing composition 35 according to the present invention is sent to the processor 31 by a transfer pump 32'', and silver recovery and fatigue fixer regeneration are performed in a fully automatic manner. However, the present invention is of course not limited thereto.Example 1 Unexposed Kodacolor film (manufactured by Eastman Kodak Co., Ltd.) was treated with various fixing solutions having different contents. The remaining silver halide was developed with a black and white developer to form blackened silver, and its optical density was measured to compare the fixing ability of the fixer.

As the bleaching solution, Oriental F5 kit bleaching solution (manufactured by Oriental Photo Industry Co., Ltd.) was used.

In addition, as a fixing solution, as shown in Table 1, the amount of ammonium thiosulfate was 100q/', 150y/', and 175q/'.
11,250y/e, and sodium sulfite at 9% each.
Various fixing solutions containing y/' and 15q/f were prepared, and potassium iodide was added thereto in amounts of 5y, 110y, and 15y. Fixer formulation Ammonium thiosulfate *1 Sodium sulfite *2 Acetic acid (90%) 3y Add water to make 1e For each fixer, we measured the time to complete fixing and compared the fixing ability. Those containing ammonium thiosulfate of 150 y/' or more showed good fixing ability despite the presence of potassium iodide.

The results are shown in Table-1. Example 2 Cog color ■ film (manufactured by Eastman Kodatsu) was applied to Noritz type K.
(2) Continuous processing was carried out using a 1307 processor (manufactured by Noritsu Kozai Co., Ltd.) according to the following steps.

In the continuous processing, Oriental F5 kit (manufactured by Oriental Photo Industry Co., Ltd.) was used as each mother liquor and replenisher.

The replenishment amount of each replenisher was as follows per film size 135 and size 20EX. Color developer replenisher 45.6m1 Bleaching 〃 34.0m1 Fixing 〃 34.0m1 Stable 〃 34.0m1 Collect the fixing solution that re-overflowed from the processor into a storage tank and use the fully automatic silver recovery device Rospar S using electrolysis method.
(Natural Science Sangyo Co., Ltd.) to produce 6 g/e of hot silver at 5
g/e was collected.

To the fatigued fixer after silver recovery, add the following regeneration composition at a ratio of 10:1 to make the amount of ammonium thiosulfate in the regenerated fixer 150q/El2OOq/f1 and the amount of sodium sulfite 25y. In this way, the playback could be repeated.

For comparison, a sample regenerated using a conventional fixing replenisher was also added to the experiment. When the fixing ability of the regenerated fixer was measured by the method shown in Example 1, the fixing ability of the regenerated fixer using the conventional fixer replenisher decreased each time the regeneration was repeated.

Moreover, in this product, the thiosulfate decomposed after 4 cycles of regeneration and it became impossible to regenerate. On the other hand, the fixing solution of the method according to the invention showed good fixing ability and could be regenerated without decomposition of thiosulfate even after more than 10 regeneration cycles. The results are shown in Table-2. Fixer regeneration composition 70% ammonium thiosulfate 700TrL1 Sodium sulfite 130q Sodium ethylenediaminetetraacetate 10y 28% ammonia water
Add 34mt water 1e
Conventional Fixing Replenishment Composition 70% Ammonium Thiosulfate 220ml Sodium Sulfite 13y 90% Acetic Acid
Add 4ml water
1e Example 3 Kodacolor film (manufactured by Eastman Kodatsu)
was continuously processed using a Noritz Type K old 307 processor (manufactured by Noritsu Kozai Co., Ltd.) according to the following steps.

Oriental F5 kit (manufactured by Oriental Photo Industry Co., Ltd.) was used as each mother liquor and replenisher in the continuous processing. The amount of each replenisher to be replenished is as follows per film size 135 size 20EX. Color developer replenisher
45.6 mL Bleaching 〃 34.0 m1 Fixing 〃 34.0 m1 Stable 〃 34.0 Collect the fixing solution that reflowed from the processor into a storage tank and use a fully automatic silver recovery device Rospar S (manufactured by Natural Science Sangyo Co., Ltd.). Using the method shown in FIG. 2, 6 da/' of hot silver was recovered at 5 y/', and fixing and regeneration was repeated four times.

In addition, for fixing regeneration, the fatigued fixer after silver recovery is divided into two parts, a conventional fixer replenishing composition as shown below is added to one part, and a fixer regenerating composition based on the present invention is added to the other part. I tried playing it. The addition ratio of the replenishing composition and the regeneration composition of the fixing solution to the fatigue solution was 10:1. Fixer regeneration composition (invention) - A solution 70% ammonium thiosulfate 700ml Sodium sulfite 130y Sodium ethylenediaminetetraacetate 10y 28 Aqueous ammonia
Add 34ml water to make 1e
PH8.5O fixing replenishment composition (conventional method) - B solution 70% ammonium thiosulfate 220ml Sodium sulfite 13y 90% acetic acid
Add 3.8ml water
Set to 1f PH6
．． 55 results are shown in Table 3.

Further, each of the above-mentioned regenerated fixing solutions was treated with a light-sensitive material in the same manner as above to reduce the fixing ability, and after recovering silver as shown in Table 3 above, each of the above regenerated fixers was added with A liquid and B liquid and regenerated.

The results are shown in Table 4. As is clear from the above table, the regenerated fixer to which the fixer regenerate composition of the present invention is added is
It had a sufficient pH value, prevented decomposition of sodium thiosulfate, and exhibited sufficient fixing speed despite the presence of iodide ions.

On the other hand, regenerated fixing solutions using conventional fixing replenishment compositions had a large amount of decomposed ammonium thiosulfate, resulting in poor fixing ability, and the presence of iodide ions significantly hindered fixing speed.

[Brief explanation of the drawing]

Figure 1 is a flow diagram showing the fixer regeneration system when a batch type silver recovery method is used; Figure 2 is a flow diagram showing the fixer regeneration system when a constant flow type silver recovery method is used; Figure 3 is a flow diagram showing the fixer regeneration system when using the processor-direct silver recovery method.

Claims (1)

[Scope of Claims] 1. In a fixer regeneration method for reusing the fixer by restoring the fixing ability of the fixer whose fixing ability has decreased due to the processing of photosensitive materials, After recovering silver using an electrolysis method, a composition for regenerating a fixer comprising a solution containing at least thiosulfate ions and sulfite ions and having a pH of 7.0 to 10.5 is added, and the above-mentioned A method for regenerating a fixer, which comprises regenerating the fixer so that the concentration of thiosulfate ions in the fixer is 150 g/l or more and the concentration of sulfite ions is 10 g/l to 100 g/l. 2. The method for regenerating a fixer according to claim 1, wherein the sulfite ion is dissociated from sulfite. 3. The fixer regeneration method according to claim 2, wherein the sulfite ions are dissociated from a sulfite ion-releasing compound.