JPH0571000A - Method for removing iron ion in plating bath solution - Google Patents

Abstract

PURPOSE:To selectively adsorb and remove only iron ion by oxidizing an iron ion in plating bath solution to trivalent by an oxidizing agent, thereafter coming a polystyrene resin base body into contact with a chelate resin having an aminocarboxylic multi-dentate ligand as a chelate ligand. CONSTITUTION:After addition of the oxidizing agent such as a hydroperoxide or ozone into the nickel (alloy) plating bath solution containing iron ion the solution is agitated to oxidizing the iron ion to trivalent. Iron ion is easily removed since bivalent iron ion, which is similar to another bivalent ion such as bivalent nickel ion in chemical property and is difficult to removed with a chelate resine, is oxidized to the trivalent. When the chelate resin having the aminocarboxylic multi-dentate ligand expressed by formula I as the chelate ligand on the polystyrene resin base body is come into contact with the plating solution, only trivalent iron ion is selectively adsobed and removed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for refining a plating bath solution, and more particularly to iron which is a contaminant ion in a nickel plating bath solution or a nickel alloy plating bath solution containing iron ions used for electroplating steel sheets. The present invention relates to a method for refining a plating bath liquid that selectively removes ions by adsorption.

[0002]

2. Description of the Related Art Steel plates are plated for rust prevention, but nickel plating or nickel alloy plating has excellent corrosion resistance, and thus the demand thereof is rapidly expanding in recent years. In the plating bath solution used in this nickel plating or nickel alloy plating, a large amount of nickel and other metals, which are the main components of the plating film, are dissolved as metal ions. When this plating bath solution is used for a long period of time, nickel and other metal ions, which are main components, are plated and decreased, while iron ions eluted from the steel plate increase in the bath solution. If the iron ion concentration in the plating bath solution exceeds the standard value, an increase in iron ions in the plating bath solution may cause unevenness or clouding on the plating surface of the steel sheet. Partial renewal or iron ion removal operation is performed.

Conventionally, as a method for removing iron ions in a plating bath solution to purify the bath solution, a method of removing iron ions by bringing the plating bath solution into contact with a chelating resin having an iminodicarboxylic acid group has been adopted. There is.

[0004]

In a plating bath solution in which nickel plating or nickel alloy plating is usually performed, nickel is 200 to 500 g / l as a sulfate and 100 to 200 g / l of other metal salts is a sulfate. Is dissolved as the main component. When a plating operation is performed using such a plating bath solution, iron ions eluted from the steel plate to be plated are increased in the plating bath solution. Usually, iron ion concentration is 10
When the amount is about 00 mg / l, the iron removal ion operation is performed, but most of the eluted iron ions are II-valent iron (II) ions, and a small amount of III-valent iron (III) ions are mixed. In this iron removal ion operation, a method using a chelate resin is adopted as described above, but since the chemical properties of iron (II) ions are similar to nickel (II) ions and other II-valent metal ions, It is generally difficult to remove iron (II) ions in the presence of a large amount of nickel (II) ions.
That is, the iron ion concentration in the plating bath solution is much smaller than that of nickel or other metal ions, and in conventional chelate resins, the affinity for iron ions does not differ much from that of other coexisting metal ions. It has a drawback that nickel and other metal ions are adsorbed simultaneously with the ions.

[0005]

The inventors of the present invention have made earnest studies on a method of removing iron ions from a nickel plating or nickel alloy plating bath solution. As a result, iron (III) ions are converted to nickel (II) ions and the like. Having different chemical properties from other II-valent metal ions of
I) The present invention has been achieved by finding that the problem can be solved by contacting with a chelating resin having a specific chelating ligand after the chemical conversion into ions.

That is, according to the present invention, a nickel plating bath solution or an alloy plating bath solution of nickel containing iron ions is made to have a trivalent value of the iron ions in the plating bath solution in the presence of an oxidizing agent, and then the polystyrene resin matrix is formed. As a chelating ligand, the following structural formula (A) And a method for removing iron ions in a plating bath solution, which comprises contacting a chelating resin having an aminopolycarboxylic acid type polydentate ligand to remove iron ions in the plating bath solution. To do.

The present invention will be described in detail below. The plating bath solution targeted by the present invention is a nickel plating bath solution or a nickel alloy plating bath solution containing iron ions used in electroplating for forming a plating film of nickel or a nickel alloy on the surface of a steel sheet. These plating bath solutions are stored in an electrolytic bath and are used for plating steel sheets. Usually, in nickel plating bath solutions, nickel is 100 to 250 g / l as a sulfate, pH 1 to 3
In the nickel alloy plating bath solution, 50 to 250 g / l of another metal salt, for example, a sulfate salt of zinc, aluminum or the like is added and controlled. Iron ions increase with the progress of plating, and when the concentration reaches a value near the control value, in order to keep the plating surface of the steel plate stable at all times, iron ions are added from the plating bath solution of this electrolytic bath. Must be removed. Iron ions are removed by a chelate resin, but the chelate resin used in the present invention has an affinity for iron (III) ions of iron (II) ions, nickel (II) ions, zinc (II) ions and aluminum (III) ions. It has a feature that it is significantly larger than the above.

Therefore, in the method of the present invention, after the plating bath solution as described above is withdrawn from the electrolytic cell, they are subjected to an oxidation treatment in the presence of an oxidizing agent to remove the II-valent iron ions mainly present in the bath solution. Perform the pre-processing to transfer the value. To change the iron ion to III-valent, hydrogen peroxide in a plating bath solution,
After adding an oxidizing agent such as ozone, a method of aeration with a stirrer, air, etc. is adopted.
Confirmation of transition to III valence is performed by measuring the redox potential of iron ion. The plating bath solution thus pretreated is then used as a chelating ligand in the above structural formula (A).
After passing through the packed layer of the chelate resin having the above to remove iron ions, the iron ions in the bath solution in the electrolytic cell are reduced by returning to the electrolytic cell again.

Usually, an electrolysis tank, a preliminary receiving tank, an oxidation tank, a filter if necessary, and a circulation system in which a chelate resin tower is connected by a pipeline, and an iron tank is provided at the outlet of the electrolysis tank and the chelate resin tower. An ion concentration sensor and an oxidation tank are equipped with a redox potential meter. Then, when the iron ion concentration of the bath liquid in the electrolysis tank exceeds a predetermined value, this device is activated by the signal of the iron ion concentration sensor, the bath liquid is once received in the preliminary receiving tank, and then the oxidation tank and the filtration tank are filtered. The iron ion is removed by flowing through the tower and the chelate resin tower in that order, and then is received again in the preliminary receiving tank, but when the iron ion concentration at the outlet of the chelate resin tower reaches or exceeds the specified value, liquid is passed by the signal of the iron ion concentration sensor. To stop. In the preliminary bath, after the nickel and other metal ion concentrations in the bath solution are checked, the bath solution is returned to the electrolytic cell and used for electroplating.

The chelate resin having the above structural formula (A) as the chelate ligand used in the present invention is produced by a conventionally known method. For example, α-amino-ε-caprolactam is used as a starting material, reacted with monochloroacetic acid, carboxymethylated, further hydrolyzed in a strong alkali, and has a polydentate ligand similar to nitrilotriacetate at the end.

[0011]

[Chemical 1]

Is synthesized. This product is reacted with a chloromethylated polystyrene resin and dimethyl sulfide to directly react with a base resin of a dimethylsulfonylated chelate resin, or with a quaternary ammonium-modified base resin by reacting with trimethylamine or dimethylaniline.
The chelate resin can be synthesized by a one-step polymer reaction. As the cross-linked polymer serving as the base of the chelate resin, the above-mentioned styrene cross-linked with divinylbenzene is adopted. The physical structure of the base resin may be either a non-porous type or a porous type, but in the present invention, the porous type is preferred from the use conditions and the like. However, in the case of porous type, the pore volume is 0.1 to 2.0 ml / g, the pore radius is 10 to 1
It is preferable to employ those having a specific surface area of 10,000 Å and a specific surface area of 1 to 1000 m ² / g.

A plating bath solution containing iron ions was added to the packed layer of the chelate resin produced as described above at an SV of 3 to 10 liters.
/ Hr. At this time, since this chelating resin has a small adsorption capacity for II-valent iron ions, it is an essential requirement that all the iron ions in the bath liquid be III-valent in advance. When the leakage of iron ions (III) from the chelate resin tower exceeds a predetermined value, the chelate resin is regenerated.
The chelate resin can be regenerated by a conventional method using a mineral acid as a regenerant, but since chlorine ions are mixed in the plating bath solution also causes unevenness of the plating surface, sulfuric acid is used as a regenerant. Is preferred. Sulfuric acid as a regenerant has a concentration of 5 to 20 w / v%, preferably 10%, a regeneration level of 10
It is possible to pass a solution of 0 to 300 g-sulfuric acid / l-resin, and the chelate resin after regeneration can be used again as a plating bath solution.

[0014]

As described above, according to the present invention, only iron ions can be selectively adsorbed and removed from the nickel plating bath or the nickel alloy plating bath containing the iron ions used for the plating treatment of the steel sheet.

[0015]

The present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. Example 1 A chelate resin having an aminopolycarboxylic acid type polydentate ligand represented by the structural formula (A) as a chelating ligand in a polystyrene resin matrix was synthesized by the following procedure.

Divinylbenzene crosslinked porous MR type chloromethylated polystyrene resin (32 to 60 mesh,
Cl content 5 ml / g-resin) and dimethylaniline were reacted by a known method as follows to synthesize a quaternary ammonium resin. To a mixed solution of 31 g of dimethylaniline, 50 ml of dichloromethane, 50 ml of methanol and 100 ml of water was added 25 g of chloromethylated polystyrene resin, and the mixture was stirred at 25 ° C for 4 days to obtain a quaternary ammonium compound (wet volume 140 ml).

[0017]

[Chemical 2]

The resin was added to 300 ml of an aqueous solution containing, the pH of the reaction solution was maintained at 10 to 12 with sodium hydroxide, and the mixture was heated at 80 ° C. for 24 hours and stirred. The reaction product obtained was filtered, washed with 2N hydrochloric acid, washed with water and dried.

[0019]

[Chemical 3]

31.2 g of a resin containing was obtained.
Hereinafter, this resin is referred to as NTA. Table 2 below shows general performance analysis values of NTA and a commercially available chelate resin. Example 2 50 ml of NTA synthesized by the procedure of Example 1 was packed in a glass column having an inner diameter of 10 mm. Next, 150 ml of 10% sulfuric acid was passed through this glass column at a flow rate of 150 ml per hour, and subsequently 150 ml of demineralized water was passed through at the same flow rate to obtain N 2.
Played the TA. Then, hydrogen peroxide solution was added to an electrolytic nickel alloy plating bath solution having the following composition to perform oxidation treatment, and after adjusting the redox potential to 500 mV, 4 liters were passed at a flow rate of 200 ml per hour.

Electroplating bath composition ZnSO ₄ 110 g / l: Total-Fe 500
mg / l: flow temperature 50 ° C. NiSO ₄ 220 g / l: pH 1.34 at 5
0 ° C

After completion of passing the solution, the electroplating bath solution remaining in the column was thoroughly washed with pure water and then regenerated. The regeneration step was carried out by passing 150 ml of 10% sulfuric acid at a flow rate of 150 ml per hour, and subsequently passing 150 ml of demineralized water at the same flow rate. In the above-mentioned regeneration process, the waste reclaimed liquid flowing out from the column outlet was received in a container and analyzed for iron, zinc and nickel contained in the reclaimed waste, and the results shown in [Table 1] below were obtained.

[Comparative Example 1] An electroplating solution was prepared in the same operating procedure and conditions as in Example except that a commercially available iminodiacetic acid type chelating resin UR50 (trade name, manufactured by Unitika Ltd.) was packed in the column instead of NTA. It passed. In the regeneration process, the waste recycling liquid flowing out from the column outlet was received in a container, and iron, zinc, and nickel contained in the waste recycling liquid were analyzed, and the results shown in Table 1 below were obtained.

[Comparative Example 2] Liquid was passed under the same procedure and conditions as in Example except that the oxidation treatment of the electroplating liquid was omitted. In the regeneration process, the waste waste liquid flowing out from the column outlet was received in a container, and iron, zinc, and nickel contained in the waste waste liquid were analyzed, and the results shown in Table 1 below were obtained.

[0025]

[Table 1]

According to the method of the present invention from Examples 1 and 2 and Comparative Examples 1 and 2, the iron ions in the electrolytic nickel alloy plating bath solution can be selectively removed and regenerated for repeated long-term use. It greatly contributes to resource saving and energy saving.

[0027]

[Table 2]

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Toshiro Yokoyama 1-193-1 Koriyama, Sendai-shi, Miyagi 1-903 (72) Inventor Fujio Koide 3- 2-3 Marunouchi, Chiyoda-ku, Tokyo Nihon Ren Rensui Co., Ltd. In-company (72) Inventor Hajime Hajime 3 2-3 Marunouchi, Chiyoda-ku, Tokyo Nihon Rensui Co., Ltd. (72) Inventor Hitoshi Usami 3 2-3 Marunouchi, Chiyoda-ku, Tokyo Nihon Rensui Co., Ltd. In the company

Claims (1)

[Claims] 1. A nickel plating bath solution or an alloy plating bath solution of nickel containing iron ions is made chelating to a polystyrene resin matrix after the iron ions in the plating bath solution are made to have a trivalent value in the presence of an oxidizing agent. As a ligand, the following structural formula (A) A method for removing iron ions from a plating bath solution, which comprises contacting a chelating resin having an aminopolycarboxylic acid type polydentate ligand shown in 1 above to remove iron ions from the plating bath solution.