[Burningkrome]

After using reverse electroplate to de-plate gold into a Sulphuric Acid solution, why can the gold not be retrieved from solution by reversing the process and plating it back onto a gold ingot?

[Enthalpy]

My gut feeling is that gold does not dissolve into sulphuric acid, even with electricity. That's why people bother with nasty salts. Did you check? The subsequent electrodeposition wouldn't work, logically.

If anything happens at the gold, it would rather fall at the bottom as a slag. But I expect instead oxygen to evolve and gold to remain intact. Do you have a link to the description of the claimed process?

[Enthalpy]

That is, the proposed "de-plate" apparatus resembles an excellent water electrolysis apparatus, with a fantastic electrolyte (sulphuric acid solution) and a fabulous corrosion-resistant electrode (gold). Hence my question, what this first step actually does.

[pcm81]

That is, the proposed "de-plate" apparatus resembles an excellent water electrolysis apparatus, with a fantastic electrolyte (sulphuric acid solution) and a fabulous corrosion-resistant electrode (gold). Hence my question, what this first step actually does.

As far as I know gold, even with electricity, can only be electro plated or stripped in aqua regia. If a sulphuric acid was able to strip gold plating, then my guess would be that such plating was probably done by the "electroless gold plating" solutions that you see for sale on line. Those solutions do not deposit pure gold, but rather a metrix of other metals with gold atoms embedded in it. Sooo... in theory... an acid could strip this "other" metal dropping the gold into solution.

[Enthalpy]

Plating on electronic circuits is pure gold to my knowledge. Especially all contacts. Anything else isn't good enough.

Electrodeposition of gold is not done with aqua regia. It's a different salt of gold that is soluble - and extremely toxic.