# Solution get darker after gold precipitation



## Hurc (Jun 12, 2022)

Dear
I have one querry please. I process rams with out IC chips. First I leached with Nitric only. Than I leached with Aqua regia. I got dark green solution. I use urea to denox and SMB for gold precipitate. I got gold precipitate but remainig solution convert to very dark green as in attached pic. I test this solution with stanous as attached video. Kindly guide me what stannous told regarding this solution. Is there any precious in solution? Why did solution turns darker? Usually after gold precipitation solution turns transparent but this one is opposite Why?
Thanks


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## orvi (Jun 12, 2022)

If overadded, SMB reduce Cu2+ to Cu+, creating complex chloride anions, that are dark coloured. Positive for gold is only violet or black. If you see brown, that´s false positive - because SnCl2 can reduce CuCl2 to CuCl too.


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## Hurc (Jun 12, 2022)

orvi said:


> If overadded, SMB reduce Cu2+ to Cu+, creating complex chloride anions, that are dark coloured. Positive for gold is only violet or black. If you see brown, that´s false positive - because SnCl2 can reduce CuCl2 to CuCl too.


Ok. Does SnCl indicate palladium as brown? Or Brown colour only indicates CuCl?


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## orvi (Jun 13, 2022)

Yes and no. Depends on concentration. I would say that Pd in solution make greenish-brown colour, in good concentrations after some time sitting deep green colour. Brown colour is due to formation of complex copper (I) and copper (II) species. If you overadd SnCl2, it will eventually go completely clear - if only copper is in solution. CuCl2 get completely reduced to CuCl - which is white 

It is important to say, that if some PM is present, colour won´t fade away if you add more SnCl2. It will reach some colouration (black-violet for Au, orange for Pt, green-brown-dark for Pd), and aside of how much SnCl2 you add, it will stay the "same" (remember that you are diluting your sample as you add more colourless SnCl2).

If I´ll have some time later, I will post some photos of what diluted gold in solution look like after stannous, and how diluted PdPt in solution look like after stannous.


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## Hurc (Jun 13, 2022)

orvi said:


> Yes and no. Depends on concentration. I would say that Pd in solution make greenish-brown colour, in good concentrations after some time sitting deep green colour. Brown colour is due to formation of complex copper (I) and copper (II) species. If you overadd SnCl2, it will eventually go completely clear - if only copper is in solution. CuCl2 get completely reduced to CuCl - which is white
> 
> It is important to say, that if some PM is present, colour won´t fade away if you add more SnCl2. It will reach some colouration (black-violet for Au, orange for Pt, green-brown-dark for Pd), and aside of how much SnCl2 you add, it will stay the "same" (remember that you are diluting your sample as you add more colourless SnCl2).
> 
> If I´ll have some time later, I will post some photos of what diluted gold in solution look like after stannous, and how diluted PdPt in solution look like after stannous.


Dear Orvi
I concentrated thqt hreen solution and did stanous again. Now it is clearly visible. Can we make any conclusion? On behalf of attached video and pic.


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## Yggdrasil (Jun 13, 2022)

Hurc said:


> Dear Orvi
> I concentrated thqt hreen solution and did stanous again. Now it is clearly visible. Can we make any conclusion? On behalf of attached video and pic.


To my eyes this is copper.
But better drip one drop of solution on paper and then a drop of stannous on same. It is easier to see then.


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## Hurc (Jun 13, 2022)

Yggdrasil said:


> To my eyes this is copper.
> But better drip one drop of solution on paper and then a drop of stannous on same. It is easier to see then.


Ok
I process 835 gm of rams without IC Chips but I got only 215 mg of gold powder. What might be the reason? Either gold not completely precipitated from this green solution. The green solitiom which I was talking about in previous messages is of these rams. I am attaching the spot test on filter paper. Kindly tell me if it indicate some thing. Video is of single spot. While pic is of multiple spot I droped on paper and use stanous on each drop.

Thanks


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## Yggdrasil (Jun 13, 2022)

Hurc said:


> Ok
> I process 835 gm of rams without IC Chips but I got only 215 mg of gold powder. What might be the reason? Either gold not completely precipitated from this green solution. The green solitiom which I was talking about in previous messages is of these rams. I am attaching the spot test on filter paper. Kindly tell me if it indicate some thing. Video is of single spot. While pic is of multiple spot I droped on paper and use stanous on each drop.
> 
> Thanks


Did you use AP first and then dissolved the foils?
Or did you go straight to AR?


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## Hurc (Jun 13, 2022)

Yggdrasil said:


> Did you use AP first and then dissolved the foils?
> Or did you go straight to AR?


I do not understand what does AP means. I first leached in diluted nitric acid than go for AR.
Thanks


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## Hurc (Jun 13, 2022)

Yggdrasil said:


> Did you use AP first and then dissolved the foils?
> Or did you go straight to AR?


I do not understand what does AP means. I first leached in diluted nitric acid than go for AR.
Tja


orvi said:


> Yes and no. Depends on concentration. I would say that Pd in solution make greenish-brown colour, in good concentrations after some time sitting deep green colour. Brown colour is due to formation of complex copper (I) and copper (II) species. If you overadd SnCl2, it will eventually go completely clear - if only copper is in solution. CuCl2 get completely reduced to CuCl - which is white
> 
> It is important to say, that if some PM is present, colour won´t fade away if you add more SnCl2. It will reach some colouration (black-violet for Au, orange for Pt, green-brown-dark for Pd), and aside of how much SnCl2 you add, it will stay the "same" (remember that you are diluting your sample as you add more colourless SnCl2).
> 
> If I´ll have some time later, I will post some photos of what diluted gold in solution look like after stannous, and how diluted PdPt in solution look like after stannous.


Dear Orvi 
As you mentioned Pd show greenish brown colour on stanous. Please find the attached video. Does it seems palladium? as blue colour converts to green with some brownish shade. This is the nitric leach of rams
Thanks


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## Hurc (Jun 13, 2022)

Hurc said:


> I do not understand what does AP means. I first leached in diluted nitric acid than go for AR.
> Tja
> 
> Dear Orvi
> ...


Here is video.


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## Shark (Jun 13, 2022)

Why would ram memory have palladium?

Did you remove the nitric before making the AR?


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## Hurc (Jun 13, 2022)

Hurc said:


> I do not understand what does AP means. I first leached in diluted nitric acid than go for AR.
> Tja
> 
> Dear Orvi
> ...


Here is video.


Shark said:


> Why would ram memory have palladium?
> 
> Did you remove the nitric before making the AR?


Yes. First removed nitric. Than use fresh nitric for AR. I make diluted aqua regia.


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## Shark (Jun 13, 2022)

If you have the gold from the solution then cement it. This will tell if there is anything left such as pgm’s or missed gold. If you used to much smb you will get the same brownish reaction in varying coloration depending on how much excess you used.

But, why would ram have palladium in the fingers?
There is no good reason for it in typical memory fingers. This would make one think there is none. Yggdrasil has already answered your question, it is copper, the brown is a false positive.


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## orvi (Jun 13, 2022)

It does not seem like palladium. Anyway, that 0,215g of gold from 800g RAM is real number. Could be higher of course, but can be that low. I encountered practically similar numbers, when I processed 50 pieces of RAM boards and get 103 mg of gold.


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## orvi (Jun 13, 2022)

Here it is. Two photos - diluted gold solution containing also some copper and other base metals (nearly transparent liquid). Next picture is after dropping one drop of SnCl2 test solution. Notice the dark violet-black tint of the test.


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## Hurc (Jun 13, 2022)

orvi said:


> It does not seem like palladium. Anyway, that 0,215g of gold from 800g RAM is real number. Could be higher of course, but can be that low. I encountered practically similar numbers, when I processed 50 pieces of RAM boards and get 103 mg of gold.


Than why are these rams so expensive. Is there any other metal in Rams? I got 100 mg of gold from 165 gm ram IC chips. Is that also ok number? Total 1kg rams. 165 gm IC chips and 835 gm rams.


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## orvi (Jun 13, 2022)

Here is pic of spent AR solution with mainly nickel, some copper and other base metals dissolved, after precipitating gold with SMB - and overdosing the solution with SMB. Notice, that brown tinge after SnCl2 is added. This is fake positive for gold. There is no gold in solution. It could look different based on composition and excess of SMB, but always - it is not violet nor dark colour.


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## orvi (Jun 13, 2022)

Here is pure solution of CuCl2 in HCL. After addition of SnCl2 to it, it get completely clear. This is how it would look like if you didn´t used excess SMB.


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## orvi (Jun 13, 2022)

Here is very diluted PtPd solution (left) and after addition of SnCl2 (right). Notice that green colour. It gets dark and brown usually when concentration is high enough. Platinum get orange always, so judging by the intensity of colour, you can assume the content very roughly.


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## orvi (Jun 13, 2022)

And here is more concentrated PtPd solution (AR) after one drop of SnCl2 test solution. Colours get deeper, green Pd stain is much more evident and even after putting the drop in, you can see some nearly brownish-dark edges. But as it diffuse, it lose that tinge and become regularly green again. Platinum is obvious and deep orange.

I do not have pure Pd in hand now. It can be difficult to spot Pd in green solution of Cu or Ni. Better to test for Pd with DMG in these cases.


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## orvi (Jun 13, 2022)

Hurc said:


> Than why are these rams so expensive. Is there any other metal in Rams? I got 100 mg of gold from 165 gm ram IC chips. Is that also ok number? Total 1kg rams. 165 gm IC chips and 835 gm rams.


Depends on what chips are on them. BGA ones can be pretty rewarding. Altough classic SMD two-side legged chips usually do not yield that much. And if you account ones that do not have gold bonding wires inside... You are going steep under 1g/kg


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## Shark (Jun 13, 2022)

Some great pictures orvi, thanks.


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## Hurc (Jun 13, 2022)

orvi said:


> Depends on what chips are on them. BGA ones can be pretty rewarding. Altough classic SMD two-side legged chips usually do not yield that much. And if you account ones that do not have gold bonding wires inside... You are going steep under 1g/kg


Thanks Orvi. I understand the Stannois results. But to vet confisent in it. I need experience. I am using DDR2 rams so there ic chips do not have two sided legs.


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## orvi (Jun 13, 2022)

Shark said:


> Some great pictures orvi, thanks.


Thanks. I choose the watchglass method, since it is more clear in terms of colour (in my opinion).

It needed some visual for beginners to see


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## Hurc (Jun 13, 2022)

orvi said:


> Thanks. I choose the watchglass method, since it is more clear in terms of colour (in my opinion).
> 
> It needed some visual for beginners to see


What I understand is to check whether stannous test is false positive or not we pour more sncl2. If the colours fade away it means false possitive. In case of PGMS increase in SnCl2 will not affect colours. Am I right? To distinguish between colours need experience. Pics you shared clear mamy doubts. Thanks


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## orvi (Jun 13, 2022)

Hurc said:


> What I understand is to check whether stannous test is false positive or not we pour more sncl2. If the colours fade away it means false possitive. In case of PGMS increase in SnCl2 will not affect colours. Am I right? To distinguish between colours need experience. Pics you shared clear mamy doubts. Thanks


Black-violet colouration when gold is present just get more diluted, when you pour more SnCl2. Same with palladium and platinum. If too much SMB was added, false positive brown colour can stay in solution for quite a long time. But now you would be able to recognize it, because it´s different colour.


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## Shark (Jun 13, 2022)

I have never used SnCl2 in the way Hurc is using it. I only use one or two drops of my solution and one or two of my SnCl2. I usually use a q-tip unless it gives me problems in determining the results. Then I use a spot plate, or a white plastic spoon.


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## orvi (Jun 14, 2022)

I am also using one/two drop max, for the photos I overexaggerated just for the better illustration. It is wasteful to use that quantity of solution in my opinion.


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## BlackLabel (Jun 14, 2022)

Hurc,

For me, it looks like your green liquid in this video is full of crystals. (SMB?)








Solution get darker after gold precipitation


Dear I have one querry please. I process rams with out IC chips. First I leached with Nitric only. Than I leached with Aqua regia. I got dark green solution. I use urea to denox and SMB for gold precipitate. I got gold precipitate but remainig solution convert to very dark green as in attached...




goldrefiningforum.com




If your test drop is full of something, your test solution will show something.

Don't take the liquid for testing from the bottom of the beaker.


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## stella polaris (Jun 15, 2022)

If processing the whole ram card, - chips, it might be some tiny MLCC containing palladium at the board. Perhaps this is enough to give indication for palladium.


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## Hurc (Jun 17, 2022)

I need one more clarification please. Gold powder I got from SMB. After few days more brown powder settle down at bottom. I separate amd wash that powder with water. After that I boil this powder in HCl. All powder dissolved in HCl. I stannous test the HCl solution amd got the result as attached. Do you have any clue what is this? Does it seems gold? Why did it dissolve in HCl?


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## Yggdrasil (Jun 17, 2022)

Hurc said:


> I need one more clarification please. Gold powder I got from SMB. After few days more brown powder settle down at bottom. I separate amd wash that powder with water. After that I boil this powder in HCl. All powder dissolved in HCl. I stannous test the HCl solution amd got the result as attached. Do you have any clue what is this? Does it seems gold? Why did it dissolve in HCl?


You probably have some oxidizer left in solution, so when you add HCl you re dissolve the Gold.


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## Hurc (Jun 17, 2022)

Yggdrasil said:


> You probably have some oxidizer left in solution, so when you add HCl you re dissolve the Gold.


What should I do to prevent this happened again in future?


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## Yggdrasil (Jun 17, 2022)

Hurc said:


> What should I do to prevent this happened again in future?


Depending on what you used to dissolve the gold.
If AR you need to properly denox it.
Bleach or Peroxide, a good long “boil” will do it.

But usually it is not an issue, put it in your stock pot and hang some thick copper slabs in there. This will deplete the oxidizer and cement out the PMs.
It needs some kind of stirring though.


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