Green solution

[rich_2137]

Hi all
I've just brought some jewellers pure gold dust and processed it with AR and the solution has turned green, the last time I used AR on pure gold powder the solution was orange, have I been stung?

Rich

 

[etack]

Sounds like cooper was in the mix. Did you test it?

Eric

 

[nickvc]

Rich when you say dust do you mean filings or actual gold coloured powder?
If it's gold coloured powder chances are you've been had, in all the years I have dealt with scrap I think I have only found 1 lot that was gold, always test with nitric before you buy if it fizzes and turns blue or green it's not gold. If however it's jewellers filings it's alloyed gold so your going to find many metals in there including PGMs possibly but also base metals and silver. The only way to find out now is to precipitate it and see if you have any gold..

 

[rich_2137]

Hi Nick, yeah it was gold colour powder, it's all dissolved in AR but the solution is green gutted as I've spent 150 quid on the stuff, I'll try to precipitate tomorrow hopefully I'll have something from it, big lesson learne!!!

 

[Lobby]

I've made absolutely beautiful 24k gold from green AuCl3 solution before.

So I wouldn't waste energy worrying until you've attempted precipitating the gold and haven't gotten anywhere. They'll be plenty of time to worry if it doesn't drop. :mrgreen:

 

[rich_2137]

Wow that makes me feel I little better as this is the same colour as mine :lol:

 

[nickvc]

Rich how did it react to the AR? If it was a slow dissolution rather than all over in 30 seconds or so you might be ok but you can always test your solution with stannous to get your answer.

 

[Oz]

Stannous is your friend!

 

[Harold_V]

Hi Nick, yeah it was gold colour powder, it's all dissolved in AR but the solution is green gutted as I've spent 150 quid on the stuff, I'll try to precipitate tomorrow hopefully I'll have something from it, big lesson learne!!!

I didn't see any mention of incineration, nor of a nitric acid wash, nor of testing with stannous chloride.

You're on a very lumpy ride, my friend. If you ignore these procedures, do not be surprised when you get stung. In my estimation, you have pretty much violated every possible safeguard you could in the way you've handled this lot of material.

Harold

 

[rich_2137]

Hi Nick, yeah it was gold colour powder, it's all dissolved in AR but the solution is green gutted as I've spent 150 quid on the stuff, I'll try to precipitate tomorrow hopefully I'll have something from it, big lesson learne!!!

I didn't see any mention of incineration, nor of a nitric acid wash, nor of testing with stannous chloride.

You're on a very lumpy ride, my friend. If you ignore these procedures, do not be surprised when you get stung. In my estimation, you have pretty much violated every possible safeguard you could in the way you've handled this lot of material.

Harold

Hi Harold
The first thing I did was incinerate the powder which clumped it together (not melted) then I washed it in HCL and warmed for around 15 mins to remove any base metals, after this the HCL was a slight green colour sort of similar to when I have wash foils in the past, should I have used nitric acid instead then and washed for a longer period of time? i guess it makes sence as this would remove silver and copper, after this is when I dissolved in AR

Rich

The reaction time was around 15 - 20 mins for it to fully dissolve
This morning I have made a fresh batch of stannous chloride and the test have come back positive

 

[Geo]

Harold is somewhat an expert when it come to jewelers sweeps, bench sweeps and floor sweeps. you will do well to pay attention to every thing he tells you. Harold didnt go to college to learn what he knows, he is a self taught man who has done everything you have done as far as refining and probably anything you will ever do (if you listen to him). remember, when Harold speaks, people listen.

 

[Lobby]

Harold is somewhat an expert when it come to jewelers sweeps, bench sweeps and floor sweeps. you will do well to pay attention to every thing he tells you. Harold didnt go to college to learn what he knows, he is a self taught man who has done everything you have done as far as refining and probably anything you will ever do (if you listen to him). remember, when Harold speaks, people listen.

Yep.

I'm collecting my sweeps, and when I have enough to process, I'll read every post Harold has made on this topic.

 

[Harold_V]

The first thing I did was incinerate the powder which clumped it together (not melted)

Excellent. It pays to make mention of such things when you post, so the readers understand how you have gone about your processing.

then I washed it in HCL and warmed for around 15 mins to remove any base metals, after this the HCL was a slight green colour sort of similar to when I have wash foils in the past, should I have used nitric acid instead then and washed for a longer period of time? i guess it makes sence as this would remove silver and copper, after this is when I dissolved in AR

Yes, I would have recommended the use of nitric. HCl won't remove silver, nor does it appreciably remove copper. I also would have screened the material after incineration, and gone through it with a small magnet, to remove ferrous particles. Yours may have been free of such contamination, but the vast majority of bench sweeps have a considerable amount of iron included (minute chips from files, and other sources). My policy was to remove the magnetic particles, work them in a mortar, then remove the magnetic particles once again, sending them to my stock pot. The remaining waste was returned to the main batch. That way any values that had hitched a ride with the magnetics would not be lost by the customer. Minuscule traces that may have remained with the magnetic particles were eventually recovered by me. Do keep in mind, my stock pot was recovered with steel, so copper was also recovered. That, for me, was the logical approach, as I sent my wastes from the stock pot to the furnace. Copper acted as a collector, so it performed a good and valuable service.

I'm encouraged to read you tested with stannous. The green coloration is most likely due to the presence of gold, which, combined with traces of copper, will yield a green solution. Looking forward to reading of your success in precipitation.

Harold

 

[patnor1011]

jewellers pure gold dust

Can you elaborate on this? What was it? Like powder in sachet placed on shelf for sale in some jewellery shop? Where did you bought that?

 

[Palladium]

jewellers pure gold dust

Can you elaborate on this? What was it? Like powder in sachet placed on shelf for sale in some jewellery shop? Where did you bought that?

Me to Patnor. Well i'm thinking if it was pure where did the copper come from? Did they say pure 24 karat gold when you bought it ?

 

[patnor1011]

Sounds more like ghanian "lifetime opportunity" gold dust sample to me. Do not take me wrong but if jeweller sell you gold dust he will not risk his good name for a few dollars profit by selling brass powder or something like that. Or it was maybe some kind of ebay wonder product? We will know more when OP get back on this with more details.

 

[rich_2137]

jewellers pure gold dust

Can you elaborate on this? What was it? Like powder in sachet placed on shelf for sale in some jewellery shop? Where did you bought that?

Hi patnor
It was a vial of gold dust/powder from a jeweller were I live so I guess he had to tell the truth as I could just go back and complain!
There was just over 5.5 grams of dust/powder, after I dissolved in AR and precipitated the powder I ended up with 4.2 grams of dried powder which was then dissolved in HCL/CL, i'll post a pick of the button soon, im trying to collect as much powder as I can before I melt I really want to get an ounce button :lol:

This is a picture after dropping with SMB and leaving overnight

This is after a HCL wash followed by a few hot and cols water wash's

This is the powder all dried

Thanks for all the help guys

Rich

 

[nickvc]

Rich have you tested your spent solutions including your rinses with stannous?
I always find doing small amounts you seem to recover less than you'd expect, I'd certainly put all these solutions through a stock pot before disposing of them at least.

 

[Geo]

i agree with nick, 1.3 grams of gold can be misplaced very easily. count how many times you did a process including washes. if you lost one tenth of a gram to each process it wouldn't take long to to misplace that much.constant testing on each step,plus being sure your washes is clear and not cloudy will cut down on some of these losses.make sure you keep a stockpot for your spent solutions.

 

[qst42know]

The brown color of your solution in this photo;

"This is a picture after dropping with SMB and leaving overnight "

can be clarified (after a negative stannous test) by bringing the solution to a gentle boil. I suspect this brown color in solution is a source of losses from using SMB.

The solution will be water clear after a light boil.