DE1621602A1 - Process for the recovery of ammonium persulfate solution - Google Patents

Description

IBM Germany International office machines GetelUcfm / t mbH

Boeblingen, August 28, 1967 bg-ma

Official file number: New registration

Applicant's file number: Docket GE 061, GE 867 024

Method for the recovery of ammonium persulphate solution

The invention relates to a method for recovering ammonium persulfate solution from a copper, ammonium, Sulphate and persulphate solution.

In the manufacture of printed electrical circuits a plastic plate, which is coated with a copper layer and a photoresist, is exposed to the line pattern. The undesired areas of the copper layer are etched away with ammonium persulfate solution, so that ultimately only the cables remain. In the manufacture of printed circuit boards, ammonium persulfate solution is used in large quantities needed. Ammonium persulfate solution is also used to etch other metal surfaces.

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009831/1376 _a . _O

The purpose of the invention is to provide a method with which the calibration resulting from the etching of the ammonium persulfate used solution of copper, ammonium, sulfate and persulfate ions converted back into an ammonium perulfate solution can be.

The invention is characterized in that the copper, ammonium, sulfate and persulfate solution with ammonia a pH of about 8.0 is set so that the solution adjusted in this way is passed over a cation exchanger saturated with ammonium ions that the metal-free Solution containing ammonium, sulfate and persulfate is anodically oxidized and that what is obtained in the process and that before existing ammonium persulfate in an ammonium persulfate solution is convicted.

An exemplary embodiment of a method according to the invention will be explained in more detail below with reference to FIG.

The used ammonium persulfate solution, which consists of copper, ammonium, sulfate and persulfate ions, is located in a container-1. With ammonia, which is in a container, the used ammonium perulfate solution is in a

Docket ge 061 q 0 9 8 3 ^{1/1 3 7 6 BAD}

Container 3, in which a stirrer 4 for an intimate mixing Eorg, mixed with enough ammonia, until the solution one Has a pH of about 8.0. As particularly useful has been proven to have a pH value between 7.5 and 8.5. With 5 there is a measuring instrument for potentiometric pH value measurement designated. This measuring instrument can open and close a valve 6 that controls the specified amount of ammonia regulates automatically.

The neutralized solution in the container 3 is over a oxidation-resistant, preferably strongly acidic cations from · = exchanger 7 passed, which is saturated with ammonium ions. When passing through the cation exchanger, the Ammonium ions are exchanged for the copper ions. The copper ions remain in the cation exchanger 7. The am The solution obtained at the outlet of the cation exchanger 7 contains ammonium, sulfate and persulfate ions. This solution is found in a container 8 passed, in which by anodic oxidation with With the help of electrodes 9, 10 the ammonium sulf «t in ammonium per sulfate is anodically oxidized. The ones in Kationenaus are more likely to do so Remaining copper ions are eluted from container 12 with dilute mineral acid, e.g. 20% sulfuric acid. The eluate enters a container 11, from which the copper by electrolysis or cementation with less noble metals, z. B. tin or Aluminum, can be recovered.

.009831 / 1376 .. '"

Docket GE 061

Thereafter, the cation exchanger 7 is removed from a container Deionized water supplied, which is used for rinsing. The flushing is continued until the one running at point 14 Rinse water has the same pH value as at the inlet, i.e. has a pH value between 5 and 7. The cation exchanger 7 is then treated with an approximately 10-20% strength Saturate ammonium stilfate solution from a container 15 and rinse until the pH is the deionized water inlet Water and at the outlet 14 are identical. The cation exchanger 7 is thus ready for a new run.

The above-mentioned electrolysis to recover the copper also produces sulfuric acid. This can, even if she still has a remnant of Kupfergehult, for the regeneration of the Cation exchanger 7 are used and are brought into the container 12 via the line 16.

Docket GE 061 '-5-

.00983 TV 1376

Claims (7)

IBM Germany International Office Masdiinen. GeselUcJi _ 16'2Ί6Ό2 Docket GE 061, GE 867 024 28, August 1967 bg-ma claims 1. Method for the recovery of ammonium persulphate solution from a copper, ammonium, sulfate and persulfate solution, characterized in that the copper, ammonium, sulfate and persulfate solution with ammonia is adjusted to a pH of about 8, 0 so that the solution adjusted in this way is above a cation exchanger saturated with ammonium ions is passed so that the metal-free ammonium obtained Solution containing sulphate and persulphate is anodically oxidized and that what is obtained and what is already present Ammonium persulfate is converted into an ammonium persulfate solution. 2. The method according to claim 1, characterized in that the copper, ammonium, sulfate and persulfate solution with Ammonia is adjusted to a pH value of 7.5 - 8.5. 3. The method according to claim 1 or 2, characterized in that dilute the copper remaining in the cation exchanger with diluted Mineral acid is eluted. . .009831 / 1376. BATH -6- 4. The method according to claim 3, characterized in that the copper from the eluate by electrolysis or cementation is recovered. 5. The method according to any one of claims 1 to 4, characterized in that that the measurement of the pH value is carried out potentiometrically. 6. The method according to claim 5, characterized in that the measuring instrument for the potentiometric measurement The valve regulates the supply of ammonia. 7. The method according to any one of claims 1 to 5, characterized in that the cation exchanger is activated for regeneration with about 20 ^ iiger sulfuric acid, then rinsed with deionized water until the draining rinse water has a pH value between 5.0 and 7, 0 and that the cation exchanger is then saturated with 10-20% ammonium sulfate solution. Docket GE 061 009831/1376