Non-Chemical Low strength HCL

[solar_plasma]

Hammer the tin flat and cut it into small pieces before you dissolve it in HCl. In fact this is part of one of the first lessons in Hoke: to cut any metal you want to dissolve into small pieces. You can speed up the process with some heating.

Pure fresh tin chloride solution is clear and colourless. But this is neither a garantee that it works nor would impurities necessarily prevent it to work. You will always test it on some standard gold solution before use.

You will find much more information in "Testing precious metals" by Miss Hoke: http://goldrefiningforum.com/~goldrefi/phpBB3/viewtopic.php?f=54&t=15573#p158717

Your 16% works fine, you don't need more concentrated for the most processes!

Yes, also your 16% HCl will look dark, but what is dark, brown, green for you or for me?...only words, you have to see it on your own. Use a small sample, maybe in a test tube, and let it sit with an excess of copper, an other with kovar. After some days they will get dark. Some air will make them more green again. If not, more HCl is needed, probably not even much.

This is something you can read a lot about (and should! - I still love to read the explainations by Butcher, LazerSteve et al.), but what people mean, you will first know, when you have seen it.

 

[steyr223]

Karlb
As solor says the 16% will work fine for everything the concentrated hcl will work on
This i can guarantee, i used 14% for the first 3-4 months for boards, pins and even some stuff i shouldn't have never used it on (i had no idea it was 14%,it was in a regular bottle )

It took a longer time to take in the copper ,i think about 6 days of constant bubbling.

Any ways look up ." Air. Or bubbler with Ap and you will understand much more

Hope this helps steyr223 rob

 

[patnor1011]

I regularly used about 10-12% strong HCl without problem. Cant say if it was slower I never had proper 32% strong stuff.

 

[KarlB]

Thanks for the help guys, in the end I managed to process around 10 mobile phone boards and 10 ram sticks in AP and then refined the gold flakes using HCL + clorox and then SMB drop. I got a small amount of light brown powder which looks shiny if you hold it under the light in the right way. I am happy with this as it's my first refined gold and I've proved to myself that the process works and I'm able to do it. I also owe alot of thanks to the kind help that members have given so far.

After a lot of hunting around I managed to find a place that would sell me 70% nitric. I think I will move towards using this as my main method due to the faster speed that it strips the base metals compared to AP and the ability to recover the silver content as well as gold. As always I will stay safe and do this outside as the fumes are nasty. I have started a new thread for my second batch to document my process and ask a small number of questions.