[mravenca]

Good morning, I think about extracting gold from pc boards, because I am able to get a lot of them. I was wondering about aqua regia and KCN.

The first option would be much better for me, I think 

I want to ask, what concetration of HCl and HNO3 do I need for creating aqua regia.

Thank you.

[AWK]

For preparing aqua regia commercial concentrated acids are used

[Borek]

Note: using aqua regia you will dissolve everything - so most of the acids will get used for dissolution of things you don't need.

[AWK]

Cyanidtion method is also very dangerous.
Think about other hydrometallurgy processes using bleach, thiosulfate or thiourea.

[mravenca]

Cyanidtion method is also very dangerous.
Think about other hydrometallurgy processes using bleach, thiosulfate or thiourea.

Can you advise me a bit how these methods work? I am not chemist 

[AWK]

Serch internet:
gold hydrometallurgy


Unfortunately, rather experienced chemist is needed for this work.

[mravenca]

So thank you very much.