Ouestion about gold dissolving

[stas208]

Hello, all
Some days ago one man demonstrated me the fastest way of gold dissolving I've ever seen before. He put scarp from polishing into container, added nitric acid and some secret powder. It took about 15 min. Does anybody know what powder could it be?

 

[jimdoc]

Then it wouldn't be a secret anymore!

Jim

 

[Harold_V]

Hello, all
Some days ago one man demonstrated me the fastest way of gold dissolving I've ever seen before. He put scarp from polishing into container, added nitric acid and some secret powder. It took about 15 min. Does anybody know what powder could it be?

15 minutes? For polishing wastes?
That's not fast.

I processed for the jewelry industry for years. Processed polishing wastes, including filters, virtually on a daily basis.

You want to hear about fast?

After a digest with HCl and a couple rinses with water, I poured AR directly to the resulting pink/purple residue. Instantly, the color shifted from pink/purple to yellow. The fine particles of gold, likely colloidal, were dissolved immediately upon contact.

That's fast.

More coarse particles of gold are almost always included in polishing wastes, so the vessel is heated to a low boil (covered with a watch glass), to keep everything in suspension while the values are dissolved. When there is no further action when a small amount of AR is introduced after the boil, values are considered to be dissolved.

Harold

 

[Drewbie]

Yes. The finer the particles the more quickly the acid will operate due to increased surface area.