Solution get darker after gold precipitation

[Hurc]

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

 

[orvi]

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.

 

[Hurc]

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?

 

[orvi]

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.

 

[Hurc]

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.

 

[Yggdrasil]

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.

 

[Hurc]

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

 

[Yggdrasil]

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?

 

[Hurc]

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

 

[Hurc]

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

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

 

[Hurc]

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

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

Here is video.

 

[Shark]

Why would ram memory have palladium?

Did you remove the nitric before making the AR?

 

[Hurc]

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

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

Here is video.

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.

 

[Shark]

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.

 

[orvi]

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.

 

[orvi]

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.

 

[Hurc]

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.

 

[orvi]

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.

 

[orvi]

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.

 

[orvi]

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.