Non-Chemical questions to a process in a video

[frank-20011]

hello,

i don't understand what the guy is doing in this video:

https://www.youtube.com/watch?v=J07lhMb0el0

he put his pins into a sollution, no gas evaporation and no disolving of the base metals so it seems to be a cyanide sollution for me.
later he put some "salt" into the filtered sollution and now you can see NOx evaporates, this looks like somebody denoxx the sollution containing NO3.

This is a contradiction: if it is cyanide, you can not denoxx it, if it is an HNO3 involving process, the base metals must go into sollution or the dissolved gold is cemmenting out by them.

Can everybody explain it to me?

regards!

 

[4metals]

The parts were definately stripped with what was likely a cyanide stripper. Most manufacturers of these strips also sell a proprietary product to strip the solution of the values stripped.

While it did appear like a red fume, ever so slightly, the material was not aqua regia or any hydrochloric oxidizer combination requiring de-noxing. The reason I say this is the gold did dissolve but the solution stayed too clean to have dissolved any base metals so it was likely a selective gold strip.

 

[frank-20011]

hello,

and thank you for your answer...you mean it's no cyanide and no HNO3-involved proces-strange stuff.

O.K. thanks and nice regards!

 

[g_axelsson]

I suspect there is a couple of steps omitted.

The amount of gold in the round flask was a lot more than could have come from the pins. The volume of the solution a lot smaller too.

My guess is that he is using a cyanide leach to strip the pins, recover it with zinc, redissolving gold in aqua regia, precipitating with SMB without denoxing first and then melting.

4metals, would gold melted directly from recovered gold from the cyanide process yield such good quality buttons, or would you require a second refining step for that?

Göran

 

[UncleBenBen]

4metals, would gold melted directly from recovered gold from the cyanide process yield such good quality buttons, or would you require a second refining step for that

Which ever the processes of recovery used, that powder looked pretty darn good until he melted it in that black hole of a dish!

 

[4metals]

I have dropped gold directly out of bombing solution and it looked that good. That is the problem with You Tube video's, you don't know what didn't make it on to the video.

 

[Geo]

Is the red fumes formed with cyanide? It may be a SSN solution and he is precipitating the gold with ascorbic acid. The red fumes are formed as the gold is precipitated and then redissolved until the nitric is depleted. Additional ascorbic acid is added until the nitric acid is depleted and the gold stays in metallic form.

 

[frank-20011]

Hello,

"I suspect there is a couple of steps omitted."

I thought so, too...something is cutted off, processes are mixed and so on...at the end short pieces of different filmes are assembled to a new and impressive looking but unreasonable new film.

Is cyanide working so fast on platings?

Why a K[Au(CN)2] is not reduced by the base metals which are present at the process but rather in zinc dust for example, is the particle size the only reason?

Regards!

 

[Anonymous]

I agree with Goran. KCN/NaCN leach with H202 oxidiser, dropped with zinc then refined in AR and precipitated out with SMB. There are large amounts missing from the video to make the process look simpler.

To answer your question plainly Frank. Yes it can be that fast, and it depends upon the strength of the solution, the temperature, the amount of oxidiser, and the thickness of the plating.

Jon

edit for spelling of leach.

2nd edit. The auric cyanide bond is stronger than an auric chloride bond by a very large order of magnitude Frank. Hence the precipition requirement for the zinc as opposed to the other base metals.