Why?

[Jmk88]

Why would anyone in their right mind even do this?

https://www.reddit.com/r/chemistry/comments/35zzox/dissolving_gold_with_nitric_and_sulfuric_acids/?utm_source=amp&utm_medium=&utm_content=post_body

I’ve read this post over and over and can not decide for myself whether this chap is talking purely from a chemistry point of view, or from a refining/practical point of view.

I think I’m swayed towards the latter which convinced me to post for clarity.

I use diluted sulphuric towards the end of my recovery process if I have over a pound of crap as i find it gives you almost a pure finish without the need for AR. If you follow Hoke properly you can identify this in there. But why would you use what this chap is saying?

Would this even be safe in a professional lab with experienced chemists?

Correction: not diluted, concentrated.

 

[butcher]

It is about the same chemistry we use in the concentrated sulfuric cell for gold recovery where gold goes into solution at the anode as gold ions and precipitates back out on its way over towards the cathode (as it leaves the oxidizing environment of the anode) and the base metals stay dissolved in the concentrated acid...

Hoke describes similar processes in her book using Hot concentrated sulfuric acid, such as on-page 53, removing base metals using acids.

Sometimes we use similar reactions in doing some of the fusion reactions with salts and metals, (under somewhat safer conditions than dealing with hot concentrate boiling acids).

 

[Jmk88]

Thanks Butcher.

I use concentrated sulphuric in the last stage of my recovery which I got from Hoke.

Only when I know there is minimal copper remaining. I then wash all my filtered material in it before diluting with water to allow my last filtration.

I find it’s also a good way of getting rid of any tissues that you’ve collected spillage with. Which is minimal for me but still.