Chemistry: Seperating gold platinum silver and copper?

Chemistry: Seperating gold platinum silver and copper?

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Discussion

menno

Original Poster:

14 posts

152 months

Thursday 13th February 2014
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I have recently discovered at my parent house, a large glass bottle filled with gold, silver, platinum and copper powder. Bottle has a large cork in the top with a candle wax type seal.

Dad was given this by his father who used to work for a metal dealer in Belgium. Dad seems to think that this must be some sort of waste product from one thing or another...

As there are several kilos of this metal powder I thought it would be worth separating them. Could anyone advise me of the process involved to achieve this.

Thank you

M

madbadger

11,617 posts

251 months

Thursday 13th February 2014
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smile

menno

Original Poster:

14 posts

152 months

Thursday 13th February 2014
quotequote all
lol, I have thought about that also. If the grains were bigger, this could well have been possible. However, this mixture is very fine. Almost equivalent in texture to flour.

Nimby

4,908 posts

157 months

Thursday 13th February 2014
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Simpo Two

87,124 posts

272 months

Thursday 13th February 2014
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Interesting. Maybe a call to Johnson Matthey?

zb

2,981 posts

171 months

Friday 14th February 2014
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They all have different melting points (in DegC);

Silver 879 - 961
Gold 1064
Platinum - 1768

That'd be the best place to start separating them.

hidetheelephants

27,861 posts

200 months

Saturday 15th February 2014
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A lot of diligent panning could bear fruit as the densities are widely spaced:

Gold 19.3
Copper 8.96
Platinum 21.5
Silver 10.5

Some Gump

12,869 posts

193 months

Saturday 15th February 2014
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Dead easy. Vibrating table, gravity and time. Speed it up with sieves..

TheEnd

15,370 posts

195 months

Saturday 15th February 2014
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Gold can be dissolved in some acids-

http://www.youtube.com/watch?v=rM87TEZXCfg


menno

Original Poster:

14 posts

152 months

Saturday 15th February 2014
quotequote all
Appreciate the replies everyone. I spoke with a specialist metal dealer (advised by BASF) who has some sort of laser apparatus which can zap this material to find out what it consists of. This technique will confirm the elements within it, but not the ratio.

If this initial analysis proves gold and platinum are present, then a small 5 gram sample will be sent for chemical analysis. It's this chemical analysis which will provide us with definitive results on quantity of each element.

The cost of separating the elements and smelting them into small bullions is just a few hundred pounds. Only worth it if the value of the precious metals outweighs the cost of smelting.

I'll keep you updated.


Simpo Two

87,124 posts

272 months

Saturday 15th February 2014
quotequote all

TheEnd said:
Gold can be dissolved in some acids-

http://www.youtube.com/watch?v=rM87TEZXCfg
I too thought of aqua regia and of extracting each metal in turn, but the chemistry would be way beyond the hope enthusiast I think.

menno said:
If this initial analysis proves gold and platinum are present, then a small 5 gram sample will be sent for chemical analysis. It's this chemical analysis which will provide us with definitive results on quantity of each element.
You'll have to ensure that the four metals are equally distributed within the powder or you'll get a false reading. That will depend on mass and particle size.

It's a nice A-level question!

Steve Campbell

2,192 posts

175 months

Sunday 16th February 2014
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Good luck in getting a representative 5g sample :-0

Interesting puzzle to have though

Tanguero

4,535 posts

208 months

Friday 21st February 2014
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You need to talk to a jewelers precious metal recovery specialist. They do this all the time at all scales. Try Landale http://www.landalemetals.co.uk/ - they will be able to advise you. If you are right about the contents and the quantity, there is potentially a significant value to it.

Edited by Tanguero on Friday 21st February 14:03

ChemicalChaos

10,525 posts

167 months

Friday 21st February 2014
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My uncle is a head engineer in the precious metal reclamation part of Johnson Matthey. I can ask him for you if you'd like

littlebasher

3,841 posts

178 months

Friday 21st February 2014
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Doesn't gold dissolve in Mercury?.....You can then boil off the mercury to leave behind the gold.

All you need to do it buy lots of thermometers!

Oh, and i wouldn't want to be breathing in any of those mercury vapors either!


RealSquirrels

11,327 posts

199 months

Saturday 22nd February 2014
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nitric acid will dissolve the silver and the copper, leaving the platinum and the gold

aqua regia will then dissolve the platinum and the gold.

the gold can be precipitated using iron(II) chloride

the platinum can be obtained as an ammonium chloroplatinate salt by adding ammonium chloride.

you'd be nuts to do it yourself, you will probably just make your materials less pure.

RealSquirrels

11,327 posts

199 months

Saturday 22nd February 2014
quotequote all
most metals will form an amalgam with mercury.

using mercury.gold amalgam and then heating to drive off the mercury is a very good way to apply gold leaf. also a good way to poison yourself quite badly. the dome of one of the cathedrals in St Petersburg was gold plated in this way, and it's still in good condition hundreds of years later.

I would talk to Johnson Mathey... we save up 5-10 years of precious metal waste and send it off to them for recovery.

moreflaps

746 posts

162 months

Tuesday 25th February 2014
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menno said:
Appreciate the replies everyone. I spoke with a specialist metal dealer (advised by BASF) who has some sort of laser apparatus which can zap this material to find out what it consists of. This technique will confirm the elements within it, but not the ratio.

If this initial analysis proves gold and platinum are present, then a small 5 gram sample will be sent for chemical analysis. It's this chemical analysis which will provide us with definitive results on quantity of each element.

The cost of separating the elements and smelting them into small bullions is just a few hundred pounds. Only worth it if the value of the precious metals outweighs the cost of smelting.

I'll keep you updated.
5 grams is not a small sample for elemental analysis. Might be worth a few $$$ tho'....

HTH

madbadger

11,617 posts

251 months

Tuesday 25th February 2014
quotequote all
moreflaps said:
menno said:
Appreciate the replies everyone. I spoke with a specialist metal dealer (advised by BASF) who has some sort of laser apparatus which can zap this material to find out what it consists of. This technique will confirm the elements within it, but not the ratio.

If this initial analysis proves gold and platinum are present, then a small 5 gram sample will be sent for chemical analysis. It's this chemical analysis which will provide us with definitive results on quantity of each element.

The cost of separating the elements and smelting them into small bullions is just a few hundred pounds. Only worth it if the value of the precious metals outweighs the cost of smelting.

I'll keep you updated.
5 grams is not a small sample for elemental analysis. Might be worth a few $$$ tho'....

HTH
yes

Our XRF kit at work uses a sample of 0.6g and that is from a non valuable sample. 5g is quite a lot.