# H2O2 and HCL solution for disolving fingers and CPU Chip pin



## catfish (May 7, 2007)

This is a comment on Steve’s tutorial on Using Hydrogen Peroxide and Hydrochloric acid to dissolve fingers from circuit boards.

I just finished a small batch of fingers, header pins, and chopped up circuit board foil. I did about 450 grams of mixed pins and fingers and etc. I started the batch on Wednesday afternoon and finished up today, Sunday afternoon, four (4) days later. All the gold was stripped off all the fiber and also the headers too. After diluting the H2O2 + HLC mix, I vacuumed filtered all the remaining material. After three separate washes with HCL and water, I partially dried the gold foil.

At the same time I performed this batch of fingers in the H2O2 +HCL mix, I started a separate batch of PII fiber chips in spent aqua regia. They were finished to day also. The settled pins contained quite a bit of copper pins too. I washed the mixed pins and soaked them in the (self made Nitric Acid) using Steve’s formula posted last week. The acid quickly dissolved all the copper and left just gold pin foil. Washed it several times in HCL and water.

I weighed the foil from the H2O2 + HCL. They weighed 6.1 grams (damp weight). The PII pin foil weighed 2.0 Grams for a total of 8.1 grams. The fingers came from an IBM 360 main frame computer circuit board. Very high gold content.

I then mixed up some aqua regia (Nitrate soda And Hydrochloric and dissolved the gold. This only took a few minutes to totally dissolve the gold foil. I now have placed it in the precipitation process and will take up tomorrow. My objective is to mine about 5 grams of good gold out of this batch.

Folks, I have learned that this method is probably one of the best methods of stripping fingers and CPU chip pins. We all have heard the old saying “It hard to teach an old dog new tricks” Well this is twice in the past two weeks, that I have learned two valuable lessons from our very own, “Lazersteve’s Tutorials” This method of dissolving fingers and CPU chip pins, and also how to make an acceptable grade of nitric acid. Both methods works great. 

I realize that these accomplishments are considered very basic to some of you old timers, but to me, I think they both are a fantastic achievement I am an old guy, but new to gold recovery/refining. Thanks, Steve for your ideas and sharing them with us newbie’s and neophytes.

Thanks again to Steve and the many others who have contributed to this forum. It doesn’t get much better than this.

Catfish


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## goldsilverpro (May 7, 2007)

Catfish,

I've never used this mix, but there's one thing that worries me about it. When the base metals finish dissolving, it seems that the possibility of dissolving gold would be greater. The metals tend to dissolve in order. After all, you have HCl and an oxidizer and that's all it takes to dissolve gold. I would suggest testing the solution for gold with stannous chloride routinely.


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## lazersteve (May 7, 2007)

Chris,

This step was included as part of the original process. Prior to disposal all liquids should be checked for gold.

Steve


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## catfish (May 7, 2007)

Goldsilverpro:

You are right about the mix could dissolve the other metals too. I did in fact check the solution after I stopped the process prior to filtering it for the gold foil. I used my precious metal detector fluid and it test very clear on a paper towel. 

One thing I have learned is to always test spent solutions for the presence of gold. I want to make sure that I get it all.

I did not dilute the mix, for I intend to reuse it again by spicing up with more H2O2 or HCL if required, as soon as I can get some more raw products.

Catfish


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## goldsilverpro (May 7, 2007)

You might try using some 12% peroxide from the beauty supply store. You've got a lot water already in there.

Try getting it out of the main solution with copper buss bar. It'll come out as a black powder, most likely. It would also drop with sodium metabisulfite.


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