# Copper Mesh Anode Demonstration: Comments and Questions



## lazersteve (May 30, 2007)

Here is where you can comment on the *Copper Mesh Anode Demo*

Steve


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## Noxx (Jun 3, 2007)

Well, very good tutorial as usual  !


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## PhillipJ (Jun 3, 2007)

Another premier production! But, where did you get the mesh?


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## lazersteve (Jun 3, 2007)

I bought a large roll of it.

Steve


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## M-G-P (Jun 4, 2007)

looks like a great way of doing Pins in simi lage amounts. Would like to see your clean up from this cell and how you deal with the copper that whent into the cell.

thanks again for another great Video. nice job Steve!


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## gold4mike (Jun 4, 2009)

I tried your (most excellent) copper anode idea using some 100% copper screen I found at Crafts 2000 and it works great, stripped 100 or so pins in very little time. The bath is already getting very black.

When I removed my lead cathode I noticed a crust of copper is forming on it. I knocked most of the copper off it after placing it in a pitcher of water for overnight storage. I don't see a large amount of copper missing from the anode (yet), and I removed the basket as soon as the pins stopped bubbling so I was surprised to see so much copper. Will I have any issues from this copper? I set my battery charger at the 6 volt/10 amp position - it won't go any lower.

Should I continue as I have been or do you have any helpful hints? 

I'm using the cell to strip the heavily plated pins from the game port of some Sound Blaster cards and some of my favorite ATI video cards. I saved 400 grams of them for the cell - can't wait to see the yield.

Thanks for your excellent tutorial on the cell construction.


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## lazersteve (Jun 4, 2009)

Mike,

The excess copper deposit may be due to the concentration of your acid. If your acid is not 95% or better strength, it may attack the copper also.

Steve


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## gold4mike (Jun 4, 2009)

I suppose that might be what's going on. I used NAPA battery acid and concentrated it on my hotplate until the temperature rose above 110 Celsius (the limit of my thermometer) and I couldn't see any more steam coming off of it at that point. I assumed that it is now concentrated but it might not be quite there yet.

I plan to clean the sludge well using HCl before dissolution/precipitation so hopefully I'll be able to get rid of the copper without too much trouble.

I have ordered a new thermometer so I can accurately monitor higher temperatures for concentration, etc.

Thanks for the rapid reply and your insight!


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## Oz (Jun 4, 2009)

You need a thermomiter with greater range or you can check concentration by mass.

Per De Dietrich...

The sulfuric acid / water system displays a maximum azeotrope at 93.3 wt% sulfuric acid concentration and a temperature of 338°C at ambient pressure conditions. A large separation factor exists as may be seen in illustration 1. Furthermore, almost no sulfuric acid is contained in the vapour up to a concentration of about 70 wt%. The vapour concentration of the sulfuric acid increases very strongly only from a fluid phase concentration of about 85 wt%.

I hope this helps.


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## lazersteve (Jun 4, 2009)

I monitor the volume until it is reduced to 1/3 of the original volume by heating.

Steve


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## gold4mike (Jun 4, 2009)

The concentration is definately the problem then. I did three batches of acid, taking each from 650 ml to approximately 400 ml. I filled my Pyrex loaf dish with about a liter of the resulting more concentrated acid. Do you think I should continue with the cell as is until full or start anew with more concentrated sulphuric? I've processed about 200 grams of pins in roughly a liter of sulphuric acid of an apparently unknown concentration. It seems to be doing a very good job of stripping gold. It's the copper I'm worried about.


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## lazersteve (Jun 4, 2009)

Mike,

I would start over with good acid, but that's just me.

Steve


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## gold4mike (Jun 5, 2009)

Will do - thanks for the advice. Getting the gold out of this mixture will be a good opportunity for me to learn new skills.

Thanks again for all you do for the forum.


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