ACIDON 4201 is Engineered and formulated for the pickling of copper and copper alloys

  1. Acidon 4201 will remove cuprous (red) oxide and other oxides, which would be left by the simple sulfuric acid pickle used to remove cupric (black) oxide scale.
  2. Acidon 4201 eliminates the pollution problems caused by chromium compounds.
  3. Acidon 4201 is compatible with both electrolytic and crystallization copper recovering processes.
  4. Metal surfaces, pickled in Acidon 4201, can improve quality appearance. Also, it resists stains during rinsing operations.
  5. With attendant copper recovery, the pickling solution may be reused indefinitely, requiring only make-up with Acidon 4201 in conjunction with a recovery process.


The use of Acidon 4201 introduces no foreign metals to the bath, thereby, greatly simplifying waste treatment and copper recovery. Note that the principal by-products of the reaction are Cu(No3),3 and water.
The pickling rate with Acidon 4201 depends only on the Acidon 4201 concentration and pickling solution temperature. The build-up of copper does not effect pickling rates in any way until the bath is saturated with cupric ions.

Crystallization – This method recovers copper as Cu(No3),3 the purity being dependent upon the quality of the acid used and what alloys are pickled.

The method is adaptable to continuous operation and can be concentrated. This recovery method takes advantage of the decrease in copper nitrate solubility with decreasing temperatures. For any but small operations, the use of external cooling (cold water coils, for example) in the crystallizing vessel is necessary.

The use of centrifugal filter on a continuing basis is suggested for large scale installations. Centrifugal filters can produce a relatively dry salt.

Electrolysis – this method of copper recovery has the advantage of recovering copper as metal and regenerating the acid in the process. Electrolytic recovery of copper from Acidon 4201 solution is quite simple. Contact General Chemical for suggestions on electrolytic recovery relative to your specific plant application.


For Acidon 4201 pickling tanks and other equipment to be used in contact with the pickling solution itself, the following materials have been found suitable:

  1. 300 Series Stainless Steels
  2. PVC
  3. Polyethylene
  4. Polypropylene
  5. Koroseal
  6. Teflon


In case of contact, immediately flush eyes with plenty of water fro at least 15 minutes. get medical attention. Flush skin with water. Wash clothing before reuse. Refer to the appropriate Material Data Safety Sheet.


Store in original closed container. Do not tamper with vent. Keep bungs n and unobstructed. Keep out of sun and away from heat. Store in a clean, cool area. Do not add any other product to this container. Empty drum completely. Never use compressed air to empty. When empty, rinse thoroughly with clean water. Use plastic valves only.


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Note: The information presented herein is our interpretation of certain test results and field experience to date. The information is not to be taken as warranty or representation for which we assume legal responsibility, nor as permission or recommendation to practice any patented invention without a license. It is offered solely for your consideration, investigation and verification.