JPS6357799A - Treatment of plating solution - Google Patents

Abstract

PURPOSE:To enable the regeneration of a chelate resin only with an acid and to inhibit the deterioration of the resin when ions of impurities accumulated in a plating soln. are removed with the chelate resin, by changing over the resin from Na type to H type. CONSTITUTION:An H type chelate resin having iminodiacetic acid groups as functional groups is used in place of an Na type chelate resin and brought into contact with a plating soln. This contact is carried out by feeding the plating soln. to a column packed with the chelate resin from the top of the column and ions of heavy metals such as Ni in the plating soln. are selectively captured by the resin. The plating soln. freed of the heavy metal ions is returned to a plating cell and plating is continued. The chelate resin having the captured heavy metal ions can be regenerated only with an acid. The H type chelate resin hardly swells or shrinks during the feeding of the plating soln. and the regeneration of the resin, so the deterioration of the resin due to wear and crushing can be inhibited.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention is directed to N, which is a contaminant ion contained in various plating solutions.
The present invention relates to a method for treating a plating solution in which heavy metals such as i, Fe, Cr, and Cu are selectively removed using a chelate resin.

<Prior Art> Since various plating solutions contain large amounts of plating metal ions, etc., a great deal of effort is required to treat the waste solutions and recover valuable components. For this reason, in recent years, plating processes have been becoming more closed in order to conserve resources and prevent environmental pollution, and efforts are being made to minimize the discharge of plating solutions, remove impurities from plating solutions, and reuse them. By adopting such a closed system, contaminant ions such as N1 ions, Fe ions, Cr ions, and Cu ions increase and accumulate in the plating solution, depending on the type of plating solution. These contaminant ions interfere with the plating process, lowering the process efficiency and causing poor quality of the resulting plated product. Therefore, a method of using a chelate resin in the Na form is known as a method for removing these contaminant ions, especially <Ni ions.

<Problems to be Solved by the Invention> However, in the method of removing contaminant -r ions using Na-type chelate resin as described above, in order to regenerate the chelate resin that has captured the contaminant ions, N is required after the elution step with acid. Since a OH is used, the running cost is high, and at this time, the swelling and contraction of the resin increases, the resin is easily crushed, and there is a problem that the deterioration of the resin increases in the case of long-term use. there were.

Means for Solving the Problems> The present invention uses an H-type chelate resin having an iminodiacetic acid group as a functional group instead of a Na-type chelate resin that requires the use of NaOH to regenerate the chelate resin. , which is characterized by its contact with a plating solution.

Contact between these H-type chelate resins, which have iminodiacetic acid groups as functional groups, and the plating solution is carried out by passing the plating solution in a downward flow through a column filled with the chelate resin. Heavy metals such as ions are selectively captured.

The plating solution from which these heavy metals have been removed is returned to the plating bath to continue the plating process. In addition, when a functional group-based chelate resin with iminodiacetic acid group is used in the H form, it is generally difficult to form a chelate with heavy metals due to the low pH of the resin, but the processing solution in the present invention is a plating solution. Because there is.

Usually sodium dihydrogen phosphate (N a H2P O4)
It is an electrolyte solution with a pH of 4 to 5, and due to this buffer effect, when the chelate resin and the plating solution come into contact, the pH is maintained at 3 or higher, and contaminant ions such as Ni form chelates with the resin. It is thought that it will become easier to be captured.

After the chelate resin and a predetermined amount of the plating solution are brought into contact with each other in this manner and the impurity ions in the plating solution are captured by the chelate resin, the chelate resin is regenerated. An acid is used to regenerate the chelate resin that has captured the contaminant ions.

Possible acids include HCQ, H2SO4, and HNO; however, if HCQ is used, carbon ions will remain in the processing solution, which will have an adverse effect on the plating process.
Preferably, SO4 is used. These regenerations of the resin using acid are performed by stopping the flow of plating solution into the column and passing acid from the acid dilution tank into the column using a pump. The regeneration level is 150-250g for H2SO4.
110-200g HCQ for H, SQ, /Q-R, HCQ
/QR.

<Function> As described above, in the present invention, since the iminodiacetic acid-based chelate resin is made into H-type and the plating solution is brought into contact with it, the impurity ions accumulated in the plating solution, such as Ni ions, are It is captured and removed as shown. In this case, the treatment solution has a concentration of 2% per 1 mon of Ni due to the above-mentioned removal reaction.
H of m0Q is released and the pH tends to decrease, and the pH
For maintenance, it is necessary to add an alkali such as NaOH.

↓↑ Also, the chelate resin that has captured Ni ions in this way is regenerated by acid as shown by the arrow on the right.

Examples are shown below.

Example A macroporous type iminodiacetic acid-based resin 35mj2RH with a particle size of 0.3 to 1.2 m was packed into a glass column with an inner diameter of 101 mφ, and a Zn plating solution having the following composition and properties was applied at a flow rate of 5 V = 8 to 10 hr. The liquid was passed in a downward flow.

Plating solution NaHz P 04: 170g/n”
Ni: 232 ppm Zn: 532 ppm pH: 4.6 Liquid temperature: 40 to 50°C The change over time in the Ni ion concentration in the treatment liquid at this time is shown by the solid line in FIG. From the figure, the amount of N1 leakage from the processing solution is 5 p.
It is good at less than pm, and the amount of Ni adsorbed is 40■Ni
/mQ-RH. On the other hand, 35 m of resin in the column
The broken line in FIG. 1 shows the change over time in the Ni ion concentration in the plating solution when Q-RH was converted into Na form with NaOH and treated with the above plating solution.

In this case, both the amount of Ni leaked and the amount of Ni adsorbed were the same as when the H type was used. Effects> The present invention as described above has the following effects.

1) Since the iminodiacetic acid group-based chelate resin can be used in the H form, it can be used only by regeneration with an acid, and there is no need to use NaOH for resin regeneration, so running costs can be reduced.

2) Also, by using the chelate resin in the H type, there is less swelling and shrinkage during regeneration after one liquid pass, and compared to when using the Na type, deterioration caused by resin abrasion and crushing is minimized. be able to.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the relationship between the amount of plating solution passed and the amount of Ni leakage in the example. Child 1 Sekiichi---Na type used IL/L"Kl"II

Claims (1)

[Scope of Claims] 1. A method for treating a plating solution, which is characterized in that when a plating solution is treated with a chelate resin having an iminodiacetic acid group as a functional group, the chelate resin is brought into H form and brought into contact with the plating solution. 2. The method for treating a plating solution according to claim 1, wherein the H-type chelate resin is regenerated with sulfuric acid.