JPH0633520B2 - Method for removing Ni ions in phosphate solution - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for removing Ni ions in a phosphate solution using a chelate resin, for example, a non-plated surface of a Zn-Ni alloy electroplated steel sheet. It is applied to the treatment of electrolytic solutions used for post-treatment.

(Prior Art) In single-sided plating of Zn-Ni alloy electroplated steel sheet, unnecessary Z attached to the non-plated surface is harmful to the non-plated surface.
It is necessary to remove n and Ni. In order to remove Ni, it is widely practiced to subject the non-plated surface to anodic electrolysis with an electrolytic solution containing sodium phosphate as a main component. At that time, Ni ions are accumulated in the electrolytic solution as the treatment amount of the plated steel sheet increases. If the concentration of Ni ions in the electrolytic solution exceeds 200 ppm, the Ni content during the electrolytic treatment of the plated steel sheet
Ions remain on the non-plated surface and the properties of the non-plated surface deteriorate.

Therefore, as disclosed in Japanese Patent Application No. 59-210584 (Japanese Patent Publication No. 63-8200), a method of removing impurities Ni, Zn and Cr in the electrolytic solution using a cation exchange resin has been proposed. For regeneration of the cation exchange resin, a strong acid such as hydrochloric acid or sulfuric acid is generally used. The cation exchange resin is regenerated with these strong acids and then washed with water to drive out the acid content remaining in the cation exchange resin. Then, the passage of the electrolytic solution to be treated is started.

(Problems to be Solved by the Invention) However, in the above method for removing impurities such as Ni, since the exchange groups of the cation exchange resin after regeneration are all H-type, the pH of the electrolytic solution immediately after the start of the passage is 1 to It is as low as 3. As a result, the electrolyte has a pH control value of pH 4 to 7 (Japanese Patent Application No. 56-136).
608 (Japanese Patent Publication No. 60-28918) will be greatly deviated. Therefore, at the start of liquid passage, a special means such as an adjusting tank was required to adjust the pH to a predetermined level.

Therefore, the present invention provides a method of directly returning the phosphate solution to the treatment bath without adjusting the pH in the step of starting the passage of the phosphate solution through the ion exchange resin after the regeneration treatment in the phosphate solution treatment. It is provided.

(Means for Solving Problems) In the method for removing Ni ions in a phosphate solution according to the present invention,
The chelate resin that has been treated with a predetermined amount of the aqueous solution is regenerated into a chelate resin having an H-type exchange group, and then Na for the H-type exchange group is regenerated.
Adjust the ratio of form exchange groups to 25:75 to 75: to 25. To regenerate the chelate resin of the H-type exchange group, a mineral acid such as H ₂ SO ₄ , HCl or HNO _{3 is} passed through the chelate resin after the above treatment. Further, in order to adjust the ratio Na / H to be in the range of 25/75 to 75/25, an aqueous NaOH solution in an amount determined by the required ratio Na / H is passed through the chelate resin of the H-type exchange group. To do.

If the ratio Na / H is less than 25/75, the p
When H becomes 4 or less, and when it exceeds 75/25, the pH becomes 7 or more, and the pH after the treatment is out of the allowable range.

(Action) When a phosphate solution containing Ni ions or the like is passed through a chelating resin having an exchange group whose ratio Na / H is in the range of 25/75 to 75/25, it is considered that the following reaction mainly takes place.

(R: resin matrix, M: Zn, Ni) Therefore, a neutralization reaction between Na ⁺ and H ⁺ occurs in the phosphate solution. Therefore, by setting the ratio Na / H to a predetermined value, the pH of the phosphate solution will be 4
Maintained at ~ 7.

(Example) Example I Chelate resin DIAION (registered trademark of Mitsubishi Kasei Kogyo Co., Ltd.) CR10 (100 ml of Na type) was filled in five columns each having a diameter of 12 mm.

The 10% H ₂ SO ₄ solution was passed through each of the first to fourth columns at 200 g-H ₂ SO ₄ / -CR10 at SV (space velocity) 2 to regenerate CR10 into H form. , 5 more demineralized water each
SV5 was passed through at a ratio of / -CR10 and washed with water. Then,
42g-NaOH / -CR10 for the 1st column, 28g-NaOH / -CR10 for the 2nd column and 14g-NaOH / for the 3rd column
-Permeate 4% NaOH solution at the rate of CR10, and N in the 4th column.
The resin layer was formed such that the Na type ratios of CR10 in the first to fourth columns were approximately 75%, 50%, 25% and 0% respectively without passing the aOH solution.

The above-mentioned operation was not added to the remaining fifth column.

Next, air was blown from the bottom of each column to thoroughly mix the resin layer, and then a sodium phosphate solution having the composition shown in Table 1, that is, an electrolytic solution was passed through the column at SV19.7.

Then, the pH, Zn and Ni concentrations of the electrolytic solution treated as described above were measured. The results were as shown in FIGS. 1 and 2.

As shown in Fig. 1, Zn ions out of the concentration of Zn and Ni ions in the treated electrolyte are expelled by Ni ions because of the smaller resin selectivity than Ni ions, but Ni ions are selected. 150 / -C processing liquid volume due to its high properties
The leak amount was small up to R10.

The pH of the treated electrolyte is 50% Na as shown in Fig. 2.
The pH of the product was constant at the specified pH 4.5 from the beginning of the spill, and Na form 7
At 5% and 25%, compared to Na form 50% at the initial outflow, it is slightly on the alkaline side or acidic side, but in both cases the treated pH is around 4.5 / CR10 and the specified pH is 4.5. ing.

On the other hand, the electrolyte treated with the 5th column of 100% Na form chelate resin is highly alkaline, and the 4th column of 0% Na form is highly acidic, and it takes a long time to reach pH 4.5. did.

Example II 200 g-H ₂ S of 10% H ₂ SO ₄ solution was applied to each column used in Example I.
After passing through O ₄ / -CR10, the adsorbed Ni was eluted to form H. Next, demineralized water was passed through SV5 at a ratio of 5 / -CR10 each and washed with water. Furthermore, Na form is 100%, 75%, 50%, 2
56% -NaOH / -CR10, 42g-Na was added to each of the first to fourth columns to form a 5% resin layer.
SV2 was passed through at a ratio of OH / -CR10, 28g-NaOH / -CR10, 14g-NaOH / -CR10. Then, air was blown from the bottom of the column to thoroughly mix the resin layer, and then the sodium phosphate solution in Table 1 was passed through.

The results were almost the same as in Example 1.

FIG. 3 is a schematic diagram showing an example of an apparatus to which the present invention is applied.

In the treatment tank 1, an electrolytic solution E containing sodium phosphate as a main component is used.
Is satisfied. The plated steel sheet S to be treated is guided by the conductive roll 3 so that the non-plated surface comes into contact with the electrolytic solution surface and is subjected to electrolytic treatment. When the Ni ion concentration of the electrolytic solution E exceeds the allowable range, the electrolytic solution E is sent to the chelate resin column 7 through the filter 5. The chelate resin in the column 7 has been previously regenerated as described above. Ni ions are removed from the electrolytic solution when passing through the chelate resin column 7, and the electrolytic solution is returned to the processing tank 1 by the pump 9. When the concentration of Zn ions increases, precipitation occurs in the processing tank 1, but most of these are removed by the filter 5. A very small amount of Zn ions that have passed through the filter 5 flow into the chelate resin column 7 and are once adsorbed by the chelate resin, but due to the selectivity, they are chromatographically pushed out to Ni ions and remain in the electrolytic solution. However, the presence of Zn ions to this extent has no adverse effect on the electrolysis process.

(Effect of the Invention) According to the present invention, the pH of the treated phosphate solution is 4 to 7 even at the start of liquid passage after the chelate resin regeneration treatment. Therefore, the phosphate solution can be directly returned to the treatment tank without adjusting the pH.

[Brief description of drawings]

FIG. 1 is a graph showing the relationship between the amount of treatment liquid and the concentrations of Ni and Zn in the treated electrolyte, FIG. 2 is a graph showing the relation between the amount of treatment liquid and the pH of the treated electrolyte, and FIG. 3 is a schematic view showing an example of an apparatus to which the present invention is applied.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI Technical display location C02F 1/42 H C22B 3/42 23/00 // C25D 5/26 P (72) Inventor Kono Norio 3 2-3 Marunouchi, Chiyoda-ku, Tokyo Within Nihon Rensui Co., Ltd. (56) Reference JP 61-91400 (JP, A) JP 57-205313 (JP, A) JP 53 -127329 (JP, A) JP-A-62-270800 (JP, A)

Claims (1)

[Claims] 1. A chelate which has been treated with a predetermined amount of an aqueous solution in an ion exchange treatment method for selectively removing Ni ions from an aqueous solution containing phosphate as a main component and containing Ni ions as impurities by using a chelate resin. Removal of Ni ion in phosphate solution, characterized in that the resin is regenerated into a chelate resin of H type exchange group, and then the ratio of Na type exchange group to H type exchange group is adjusted to 25:75 to 75:25. Method.