JPS588913B2 - Pyrolin Sandwich - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a copper pyrophosphate plating aging solution used as a cyanide-free copper plating bath and a method for removing copper ions contained in the plating cleaning water.

Is the waste liquid generally discharged from these copper plating processes? Copper ions (Cu") are dissolved in the pyrophosphate ion-excessive yarn where the ratio of copper ions to pyrophosphate ions (P ratio) expressed as P ratio = P204-/Cu2+ (weight ratio) is about 7.5. Therefore, it exists in the stable form of copper pyrophosphate complex ion (CLI(P207)2)-6.

In addition, this waste liquid also contains K+, Na+, and P.
Ions such as 204- also coexist.

Since the copper pyrophosphate complex ions in this waste liquid are stable against alkalis, it is possible to apply the usual copper ion treatment method of adding alkali to adjust the pH to around 9 and removing copper as hydroxide steel. Have difficulty.

Therefore, currently, the treatment of liquids containing copper pyrophosphate complexes involves diluting the waste liquid with a large amount of water to weaken the stability of the steel pyrophosphate complex ions, and then adding alkali to remove some of the copper contained as copper hydroxide. However, the copper is not completely processed.

In addition, since copper ions form a complex and exist as hexavalent anions, removal using an anion exchange resin is considered, but in this method, 6 grams equivalent of the exchange resin is required to adsorb 1 mole of copper. This method has drawbacks such as the need for an exchange group and the coexistence of other anions, resulting in an extremely low resin utilization rate for copper ion adsorption, so it is not a very useful method industrially and is rarely practiced. It is.

The inventors feared that if even a small amount of copper ions remained in the waste liquid discharged from the copper plating process, it would cause various types of destruction to the natural environment, so they removed copper ions from the treated water until they could no longer be detected with an atomic absorption spectrophotometer. As a result of intensive research on methods for this purpose, we have arrived at the present invention, which allows copper plating waste liquid to be treated on an industrial scale.

That is, when removing copper from a solution containing a pyrophosphate complex salt, the present invention adds a calcium source of 2 to 10 times the number of moles of copper contained in the solution to generate a copper pyrophosphate double salt, which is then removed. This is a method for treating a liquid containing a copper pyrophosphate complex, which is characterized in that after the liquid is filtered, copper ions remaining in the filtrate are adsorbed using a chelating ion exchange resin.

The present invention will be explained in detail.

The present invention includes a first step of adding a calcium source to a solution containing a copper pyrophosphate complex salt to produce a copper calcium pyrophosphate double salt and precipitating and separating it, a second step of filtering the treated solution from which the produced double salt has been separated, and A third step of treating the filtrate with a chelating ion exchange resin is performed sequentially.

Various calcium compounds can be used as the calcium source used in the first step of the present invention, but calcium chloride and calcium hydroxide are particularly inexpensive and useful.

The required amount of calcium source to be added varies depending on the P ratio in the treatment solution, but it is 2 to 1 mole of copper ions in the solution.
0x is the most efficient.

In other words, when the amount of calcium source added is less than twice the number of moles of copper ions, the removal rate of copper ions decreases;
If it is added in an amount greater than 0 times, calcium salts will be produced in the produced precipitate, which will only increase the amount of sludge and increase the cost of adding the chemical, which is meaningless.

The reaction between the copper pyrophosphate complex and the calcium source proceeds chemically equivalently, and when the P ratio is 7.5, it is most efficient to add 4 times the number of moles of copper as the calcium source; 94% or more of the copper can be precipitated and separated as copper calcium pyrophosphate double salt.

Although the first step of the present invention cannot completely remove copper ions to the point where they are no longer detectable, most of the copper complexes can be efficiently solid-liquid separated using inexpensive chemicals, and the copper ions can be completely removed in the next step. This is an important step indispensable to the removal process.

In the present invention, the treatment liquid separated into solid and liquid in the first step is filtered in the second step and then treated with a chelating ion exchange resin in the third step. The step of filtering the treatment liquid obtained in the first step is essential.

In other words, even after solid-liquid separation of the insoluble copper calcium pyrophosphate double salt in the first step, minute amounts of suspended matter always remain in industrial processing, so the filtration in the second step is omitted and the chelate is removed in the third step. When the water treated in the first step is directly passed through the ion exchange resin layer, minute suspended matter adheres to the resin layer, hindering the diffusion of copper ions into the resin sphere.
This is because the complete adsorption treatment of copper ions is prevented, and the copper ion adsorption utilization rate of the resin is significantly reduced.

The filtration in the second step is preferably precision filtration;
Does the process completely remove copper in the filtrate on an industrial scale? This is also an important point.

In the third step of the present invention, the copper ions remaining in the first step treatment are treated with a chelating ion exchange resin, so that the copper ions in the treated water become completely undetectable by atomic absorption spectrometry (0.
1 ppm or less).

The advantage of using the chelating ion exchange resin in the third step is that it has high selectivity for adsorbing copper ions, so it adsorbs only copper ions without being greatly affected by the coexisting Na, K, and Ca ions. In addition, since the chelate resin treatment is performed after the copper ion concentration has been reduced to a low concentration in the first and second step treatments, the load on the chelate resin is reduced, making it suitable for long-term use and Even when it comes to treating the amount of wastewater, it is possible to completely treat it with a small resin tower.

In addition, in the present invention, excess P204- is removed as calcium pyrophosphate by the calcium source addition treatment in the first step, so copper pyrophosphate One of the features is that since the stability of the complex salt is weakened, the copper ion adsorption utilization rate of the resin is significantly improved.

When a conventional cation exchange resin is used in the third step,
Since copper cannot be completely removed even when the stability of the copper pyrophosphate complex is somewhat weakened, the cation exchange resin cannot be used in the third step of the present invention.

In the third step, the copper ions adsorbed on the chelating ion exchange resin are eluted with mineral acid, and the resin can be repeatedly reused.

Examples of the chelating ion exchange resin used in the third step of the present invention include styrene divinylbenzene copolymer,
Diethylenetriamine,
triethylenetetramine, tetraethylenepentamine,
Products containing amines such as pentaethylenehexamine, iminodiacetic acid, or reactants of the above amines with aminocarboxylic acids such as halogenated acetic acid, alcohol amines such as diethanolamine and dipropanolamine, and ureas such as urea and thiourea. can be given.

Next, the present invention will be explained in more detail with reference to Examples.

Example 1 A waste solution containing 150% copper, obtained by adding copper pyrophosphate plating washing water to the copper pyrophosphate plating bath shown below, was used in the test.

Copper pyrophosphate plating bath First, as a first step treatment, 1050 calcium chloride was added to the copper pyrophosphate complex solution containing 150 ppm of copper.
ppm (four times the molar concentration of Cu as a Ca source), stirred for 15 minutes, and adjusted the pH to 9.0 with caustic soda.
The precipitate of copper calcium pyrophosphate double salt was allowed to settle for 30 minutes.

Next, the supernatant liquid of the first step treated water was filtered through qualitative filter paper.

The copper concentration remaining in the filtrate was 8%. The filtrate thus obtained was treated with a chelating ion exchange resin
A glass force ram (φ-3.0 crIl) was filled with 400 ml of a phenolic resin having iminodiacetic acid as a functional group produced by the method described in Publication No. 9391, and the filtrate after the second step was passed through at a flow rate of 4000 mVHr. When the copper concentration of the liquid effluent from the resin layer was measured by atomic absorption spectrophotometry, no copper ions were detected.

The values of copper concentration in the effluent are as follows.

Claims (1)

[Claims] 1 When removing copper from a solution containing copper pyrophosphate complex salt,
A calcium source with an amount of 2 to 10 times the number of moles of copper contained in the solution is added to generate and remove copper pyrophosphate double salt, and then the treated solution is filtered, and a chelating ion exchange resin is used to remove the calcium source remaining in the filtrate. A method for treating a liquid containing a copper pyrophosphate complex, characterized by adsorbing copper ions.