ChuckNC
Harmless
Posts: 4
Registered: 24-12-2005
Member Is Offline
Mood: sleepy
|
|
Platinum Recovery via CN?
Hi guys.
This might be a little off the wall, but as Au and Ag are soluble in a basic solution of CN, are Platinum Group Metals? I have heard about it being
done, but at what temps and pressures?
Anyway, I have a feeling it's not for the small guy.
I am familiar with using CN, it's hazards, how to neutalize and dispossal also.
Any info would be appreciated.
Chuck
|
|
|
Fleaker
International Hazard
Posts: 1252
Registered: 19-6-2005
Member Is Offline
Mood: nucleophilic
|
|
To my knowledge Chuck, cyanide will complex with platinum but not to the convenient extent that gold and silver do. KCN is used more with Ag and Au
for that reason, with leaching/floatation being common treatment for ores. I've never worked much with cyanide solutions but for plating baths.
Cyanide appears to be of limited utility when working with platinum as many prefer to use halide/sulfuric acid route, which is in many ways, an
aqueous version of gas phase transport via halogen gas (where the halogen serves as the oxidizing agent)
This link, if it works, might be of interest:
http://doc.tms.org/ezMerchant/prodtms.nsf/ProductLookupItemI...
This is the sulfuric acid/oxidizer/halide ion method which works well for platinum and in particular rhodium from catalytic converters:
http://www.freepatentsonline.com/5304359.html
Edit--Welcome to the Board!
[Edited on 28-7-2006 by Fleaker]
|
|
|
ChuckNC
Harmless
Posts: 4
Registered: 24-12-2005
Member Is Offline
Mood: sleepy
|
|
Thanks for the welcome Fleaker.
First link won't work for me. Second one is very interesting.
Chuck
|
|
|
Vitus_Verdegast
Hazard to Others
Posts: 297
Registered: 5-12-2004
Location: Ottoman Empire
Member Is Offline
Mood: tea time
|
|
Chuck:
try this for the first link:
http://tinyurl.com/z94a4
Sic transit gloria mundi
|
|
|
JohnWW
International Hazard
Posts: 2849
Registered: 27-7-2004
Location: New Zealand
Member Is Offline
Mood: No Mood
|
|
I thought that aqua regia (HNO3 + HCl) was standard for dissolving platinum group metals.
|
|
|
not_important
International Hazard
Posts: 3873
Registered: 21-7-2006
Member Is Offline
Mood: No Mood
|
|
They have been, but on a large scale the off-gassing is a problem, the acids are relatively costly, and for some processing you need to evaporate down
the solution, add more HCl, evaporate, and so on to remove nitrate. Aqua regia is still good on a small scale, but industrial types have been
considering alternatives for years..
Which brings up a possible reason for not using cyanide. In many cases you are dealing with a mix of the platinum metals, either alloys and/or mixed
scrap. From what I remember many of the separation schemes take place moostly in acid solution and/or with halides.
|
|
|
Fleaker
International Hazard
Posts: 1252
Registered: 19-6-2005
Member Is Offline
Mood: nucleophilic
|
|
Also JohnWW, aqua regia has to be heated to dissolve platinum, at room temp, it barely affects the metal. Works excellently for gold though.
Remember Chuck, always work with basified cyanide solutions!
|
|
|
jokull
National Hazard
Posts: 506
Registered: 22-2-2006
Location: Everywhere
Member Is Offline
Mood: Ice glassed
|
|
Hi Chuck!
I'd like to know what material are you interested to complex platinum from. is it a solution? an alloy?
Is it really necessary to use cyanides?
|
|
|
ChuckNC
Harmless
Posts: 4
Registered: 24-12-2005
Member Is Offline
Mood: sleepy
|
|
Jokull,
Mainly I'm interested in stripping catalytic converters and a deposit I have found. I'm intimately aware of using Aqua Regia, but was looking at CN
only because it does so well on Au and Ag. It's not needed, but I had read somewhere about the pressures and temps needed to digest PGM's in CN and
wanted to see if anyone here was familiar with it.
Mainly just a quest for a little knowledge.
Chuck
|
|
|
ChuckNC
Harmless
Posts: 4
Registered: 24-12-2005
Member Is Offline
Mood: sleepy
|
|
Well after studying the supplied sites, I'll stick with AR. Simple and easy to use, and I don't need to use extra electricity to recover the Pt and
Pd. I will keep it in mind for the Rh though.
|
|
|
![[*]](images/xpblue/default_icon.gif){kind=icon}
