JP3112805B2 - Method of treating iron chloride solution containing nickel - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for regenerating an etching solution containing ferric chloride as a main component which is used in a manufacturing process of a shadow mask for a cathode ray tube, a lead frame for a semiconductor and the like. .

[0002]

2. Description of the Related Art In a manufacturing process of a shadow mask or the like, a thin metal plate made of a nickel alloy is immersed in an etching solution to be processed into a desired fine pattern. In this step,
As the nickel alloy elutes with the progress of etching,
The etching ability of the liquid gradually decreases, and eventually becomes a waste liquid that is difficult to use.

From the viewpoint of economy and resource saving, it is desirable to regenerate and recycle the etching waste liquid. However, the etching waste liquid usually contains nickel of about several thousand ppm to 10,000 ppm which lowers the capacity as an etching liquid. It is present, and in order to reuse the etching waste liquid, it is necessary to suppress the nickel content to, for example, 500 ppm or less.

Therefore, various attempts have been made in the past to regenerate such waste liquid and restore the etching ability. For example, Japanese Unexamined Patent Publication (Kokai) No. 61-104092 discloses that an etching waste liquid containing a ferrous salt and containing a ferrous salt as an active ingredient is supplied to an anode chamber of an electrolytic cell partitioned by an ion exchange membrane to continuously oxidize the solution. It is disclosed to regenerate. In this method, the reaction from ferrous iron to ferrous iron is performed at a current efficiency of about 1
It is said that it can be performed at 00%.

[0005] However, in this method, since the diaphragm used is an anion exchange membrane, cations, particularly divalent nickel, in the waste liquid to be regenerated cannot be moved to the cathode side. Further, in the example of the publication, Fe
The addition of Cl ₃ keeps NiCl ₂ at a constant concentration, and this method necessitates a separate treatment by discharging the increasing iron chloride solution. Further, the ion-exchange membrane used is relatively expensive and has poor durability, handling is complicated, and there is a difficulty in practicality.

[0006]

SUMMARY OF THE INVENTION
Similarly, Japanese Patent Laid-Open No.
In Japanese Patent No. 0475, nickel and iron are electrodeposited and recovered at a cathode by using an electrically neutral diaphragm having a small electric resistance, and at the anode, divalent iron ions contained at the anode are oxidized to trivalent iron ions. Chlorine gas is also
It is proposed to use it effectively for the oxidation of the etchant containing iron.

[0007] As a more excellent method, an iron chloride-based etchant containing nickel is supplied to an electrolytic cell having an electrically neutral diaphragm having a small electric resistance, and the metal is charged on the cathode side of the electrolytic cell. Electrolytic oxidation at the anode side
In the method of continuously regenerating an etching waste liquid by using trivalent iron as the ferric iron and using chlorine gas generated on the anode side as an oxidizing agent, a solution having the same composition is obtained by batch processing in the same electrolytic cell. It has also been proposed to determine the amount of processing solution per unit time at which the desired metal ratio is obtained from the relationship between the amount of electricity and the composition of the deposited metal, and supply the solution to the electrolytic cell with the amount of solution per unit time (Japanese Patent Application Hei 6-309031).

[0008] According to such a method, in order to take out only the nickel-iron alloy eluted in the etching step, Ni / F in the metal deposited and recovered on the cathode side of the electrolytic cell.
The e ratio was controlled so that all other components could be recycled. However, this method is a good method for reducing the amount of Ni contained in the waste liquid to several percent to about 1/5, but further increasing the removal rate and reducing the nickel concentration remaining in the recovered liquid. It is extremely difficult to reduce it to the same level as a new liquid from the viewpoint of economy. In addition, in electrolysis, since the contents of iron and nickel in the deposited metal change with the progress of electrolysis, it is difficult to obtain a stable precipitate. In addition, the adhesive nickel / iron alloy deposited on the electrode plate is liable to be distorted, cracked, and dendritic.

On the other hand, there are a series of proposals for removing nickel by adding metallic iron. For example, JP-A-5-26327
No. 3 discloses that, when iron powder is added to a solution obtained by adding an iron material to an aqueous solution of iron chloride to remove and recover nickel from the aqueous solution, iron powder necessary for nickel precipitation is divided and added. It is disclosed that the nickel which precipitates on the surface is separated in each case. In the treatment by such a so-called iron replacement method, the nickel concentration remaining in the regenerating solution is reduced to 100 p.
pm, and it is easy to collect the precipitated metal by filtration together with the iron material, but it is easy. However, a solution containing a large amount of trivalent iron, such as a waste solution used in the production of the above-mentioned shadow mask and lead frame. When processing

[0010]

(Equation 1)

Prior to the reaction of

[0012]

(Equation 2)

In the case of a solution containing a large amount of ferric chloride, for example, 200 g / l, a large amount of excess iron chloride is generated, and it is currently difficult to dispose of the solution. .

In view of the above-mentioned problems of the prior art, the present invention takes advantage of the ease of deposit recovery and high nickel recovery, which are the advantages of the iron substitution method, and extremely suppresses the generation of excess iron chloride, which is a disadvantage of the method. An object of the present invention is to provide a method for regenerating an etched liquid.

[0015]

The present invention solves the above problems,
After electrolytically reducing a solution containing ferric chloride and nickel chloride as main components and converting at least a part of ferric iron contained in the solution into ferrous iron, the reducing solution is brought into contact with an iron material,
The problem was solved by reducing and depositing nickel contained in the solution.

That is, in order to avoid the generation of excess iron chloride,
The reduction reaction from trivalent iron to ferrous iron is performed by a so-called electrolytic method, and an iron material is charged into the solution after the electrolytic treatment to remove nickel. In this electrolytic treatment, it is preferable to use an electrolytic cell having an electrically neutral diaphragm having a small electric resistance.

As the iron material used in the substitution reaction, it is preferable to use iron powder which can be easily handled and has a large contact area. For example, the particle size is preferably 100 mesh passes or more, and more preferably 150 to 350 mesh passes. Further, when the specific surface area is 1 m ² / g or more, nickel removal efficiency increases, which is preferable.

In the above electrolysis step, trivalent iron is reduced to ferrous iron on the cathode side. However, chlorine ions transferred to the anode through the diaphragm are discharged to generate chlorine gas. It is advantageous to effectively utilize the oxidation of ferrous iron contained in the solution after nickel is reduced and precipitated.

It is also advantageous that the solution after nickel is precipitated by reduction is sent to the anode side in the electrolysis step to oxidize and regenerate the ferrous iron contained in the solution to ferric iron.

[0020]

The present invention will now be described in more detail with reference to Examples.
explain.Example 1 As shown in FIG. 1, 17 g / liter of divalent iron component
196 g / liter of trivalent iron component, nickel component 1
5.8 g / l, chlorine component 411.4 g / l
500 ml of waste liquid having the composition of
In the cathode chamber (cathode: titanium plate) of the electrolytic cell 1 having a diaphragm of
The same composition solution was introduced into the anode chamber (anode: RuO _Two/ Ti net
(DSA electrode)) (250 ml), constant current 1
0 A, current density of 20 mA / cm for both cathode and anode^Two,
Electrolysis was performed under a pressure of 2.0 V. Liquid temperature during electrolysis is 65 ° C
Kept.

As a result, on the cathode side, a divalent iron component of 211 g / liter and a trivalent iron component of 0.5 g / l
500 ml of a ferrous chloride solution having a composition of less than 1 liter, a nickel component of 15.8 g / liter and a chlorine component of 285 g / liter were obtained. On the other hand, chlorine gas 58.
Since 5 g was generated, it was sent to the absorption tower 2.

Next, the obtained ferrous chloride solution 50
0 ml was introduced into the iron replacement tank 3, and about 38 g of iron powder (equivalent to 5 times the molar amount of Ni in the liquid) was charged in three portions, and stirred at a liquid temperature of 60 ° C. for a total of 48 hours ( The reaction was performed over 16 hours x 3).

Next, when the liquid after the reaction was filtered,
228 g / liter of divalent iron component 0.5 of trivalent iron component
500 ml of a recovery liquid having a composition of less than g / l, a nickel component of 110 mg / l and a chlorine component of 285 g / l, and 41 g of metal powder consisting of 77.5% of Fe and 19.2% of Ni were obtained.

In the above-mentioned electrolytic reduction step, a small amount of foil-like metal was deposited on the cathode plate, but could be easily scraped off from the electrode. The composition of the deposited metal is Fe = 12%,
Ni = 87% and the weight was 0.3 g.

Finally, 500 ml of the above-mentioned recovered liquid was added to the absorption tower 2
And brought into contact with chlorine gas generated in the electrolytic cell 1. The liquid composition after absorption of chlorine gas is as follows: divalent iron component 44 g / liter, trivalent iron component 184 g / liter, nickel component 1
The amount was 10 mg / liter and the chlorine component was 402 g / liter. The required power at this time was 110.7 wh (1.13 wh per gram of reduced ferric iron).

Embodiment 2 As shown in FIG. 2, the electrolytic cell 1
Of 500 ml of the same liquid composition was introduced into the cathode chamber of No. 1 and electrolyzed under the same conditions. As a result, on the cathode side, 2
213g / liter of trivalent iron component 0.5g of trivalent iron component
Per liter, nickel component 15.9 g / liter,
500 ml of a ferrous chloride solution having a composition of 286 g / liter of a chlorine component was obtained.

Next, 500 ml of the ferrous chloride solution was introduced into the iron substitution tank 3, and about 38 g of iron powder (equivalent to 5 times the molar amount of Ni in the liquid) was charged in three portions and stirred. The reaction was carried out at a liquid temperature of 65 ° C. for a total of 48 hours (16 hours × 3).

Next, when the liquid after the reaction was filtered,
228 g / liter of divalent iron component 0.5 of trivalent iron component
500 ml of a recovery liquid having a composition of less than g / l, a nickel component of 120 mg / l and a chlorine component of 285 g / l, and 40 g of a metal powder composed of 76.3% of Fe and 19.8% of Ni were obtained.

500 ml of the recovered solution was introduced into the anode chamber of the membrane electrolyzer 1 and the composition of the solution after the electrolysis was examined. As a result, 46.3 g / liter of divalent iron component and 182 g / liter of trivalent iron component were obtained.
Liter, nickel component 120 mg / liter, chlorine component 401 g / liter. The required power at this time is
112 wh. There was no generation of chlorine gas.

Comparative Example 17 g / liter of divalent iron component 196 g of trivalent iron component
/ 500, 15.8 g / l of nickel component and 411.4 g / l of chlorine component
95 g of iron powder was added to the mixture, and about 220 ml of pure water was added. The mixture was allowed to react at a liquid temperature of 60 ° C. for 48 hours while occasionally removing hydrochloric acid so that pH <1.
29 g / liter, trivalent iron component less than 0.5 g / liter, nickel component 200 mg / liter, chlorine component 28
720 ml of a liquid having a composition of 6 g / liter and Fe =
45 g of a metal powder composed of 82% and Ni = 16% was obtained.

The excess iron chloride generation rate of the example and the comparative example increased by 7% in the example and increased by 54% in the comparative example, which almost coincided with the theoretical value.

[0032]

According to the first aspect of the invention, in order to avoid the generation of excess iron chloride, the reduction reaction from trivalent iron to ferrous iron is performed by a so-called electrolytic method, and the solution after the electrolytic treatment is treated. Since nickel is removed by adding iron material to the furnace, the amount of surplus iron chloride generated can be reduced to about the same mole as the recovered nickel, and nickel containing several percent is removed to a level close to a new solution of, for example, 500 ppm or less. And a voltage (1) lower than about 3 to 4 V pointed out in a conventional Japanese Patent Application Laid-Open No. 6-240475, for example, by using an electrolytic apparatus that does not require a complicated mechanism for recovering deposits from the electrodes. 0.5-2.5
Since the electrolytic reduction is performed in V) and metal deposition can be performed, a low-cost and high-efficiency regeneration system can be realized.

According to the second aspect of the present invention, the chlorine gas generated by the chlorine ions moved to the anode through the diaphragm in the electrolysis step is used to oxidize the divalent iron contained in the solution after the nickel is reduced and precipitated. Since it can be effectively used, there is no need to consider suppressing the gas generation unlike the related art, and the reaction in the electrolysis step can be used effectively.

According to the third aspect of the present invention, the solution obtained by reducing and depositing nickel is sent to the anode side in the electrolysis step, and the ferrous iron contained in the solution is oxidized and regenerated to trivalent iron.
Both electrode reactions in the electrolysis step can be effectively utilized.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram illustrating a processing step according to the present invention.

FIG. 2 is a conceptual diagram illustrating another processing step according to the present invention.

[Explanation of symbols]

 1 diaphragm electrolysis tank 2 absorption tower 3 iron replacement tank

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Mikami Yasushiya 2-1 Hirai-cho, Hinodecho, Nishitama-gun, Tokyo Nippon Steel Mining Co., Ltd. (72) Inventor Masayoshi Kato Kosugaga, Sakae-ku, Yokohama-shi, Kanagawa Tani 1-11-2 (56) References JP-A-55-18558 (JP, A) JP-A-5-263273 (JP, A) JP-A-6-240475 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C23F 1/46 C02F 1/461

Claims (3)

(57) [Claims] 1. A solution containing ferric chloride and nickel chloride as main components is electrolytically reduced, and at least a part of ferric iron contained in the solution is converted to divalent iron. A method in which nickel contained in a solution is reduced and precipitated by contact. 2. The method according to claim 1, wherein chlorine gas generated during the electrolysis step is used for oxidizing ferrous iron contained in the solution after nickel is reduced and precipitated. 3. The method according to claim 1, wherein the solution after the nickel is reduced and precipitated is sent to the anode side in the electrolysis step, and the ferrous iron contained in the solution is oxidized and regenerated to trivalent iron. the method of.