First and foremost, the name for the process, Acid Peroxide is a misnomer as the active ingredient is actually copper II chloride (CuCl2), so it should have been called the Copper II Chloride Etching process. Once the copper II chloride (C2C ) is formed it is reusable indefinitely if you take care not to foul the solution. Once formed all you need is air, HCl, and water to keep things going forever using the same solution. Your only problem will be the ever increasing volume of the C2C solution and it's proper disposal.
Secondly, C2C should be used primarily to remove copper from gold bearing scrap before attempting to digest the gold. If the plated scrap is magnetic (kovar or iron/steel) then AP (C2C) is not the process to use.
The last key note is that if you use too much hydrogen peroxide (3%) to initally generate your copper II chloride you may dissolve some of your gold into solution. If you think more is better and add too much too quickly or use too high of a concentration of hydrogen peroxide you will dissolve gold. The peroxide is a catalyst for the reaction, not the active ingredient. If you do this then simply keep using your AP as directed without adding any peroxide until it becomes saturated with copper and the gold will cement out on it's own. There is no need to add any other precipitants to the solution and doing so will foul the solution.
If you haven't read the Copper II Chloride etchant document on my website in the documents section now is the time to do so. You'll be light years ahead of the game as to what to look for and what the various colors of the solution indicate. You'll also have all the chemistry information you could want on the topic.
Now to the consolidation of previous Q&A's on the topic:
- Learning AP: AP Acquaintance Test Setup
- AP Common Facts: Acid Peroxide Notes
- AP Q&A: Acid Peroxide Help
- AP Cleaning Foils: Gray Powder in Foils
- AP Waste: Dealing with Excess AP
- Summary of AP Clean up
If you are a visual learner then you can watch the Acid Peroxide videos for free on my website or you can buy the full length DVD: Processing Finger Boards with Acid Peroxide at my web store, it's the first item on the list.
This post is a work in progress and will be updated as I have free time to consolidate the information scattered across the forum.