From: whitbeck@equinox.unr.edu (Michael Whitbeck)
Newsgroups: sci.chem
Subject: Re: Gold - future Auto Catalyst
Date: 18 Nov 92 02:18:16 GMT
Organization: University of Nevada, Reno

In article <1992Nov16.223502.27207@alchemy.chem.utoronto.ca> mroussel@alchemy.chem.utoronto.ca (Marc Roussel) writes:
:In article <1992Nov16.193403.16355@news.clarkson.edu>
:rajat@sunny3.che.clarkson.edu (Rajat Kapoor,P303,2124) writes:
:>One of the unfortunate fallouts, IMHO, of the above reaction is that the
:>Japanese plan to use Au as one of the active materials for catalytic
:>convertors. 
:[...]
:>Gold has a charm like no other metal.
:>Putting this in ceramic monoliths would make it practically irrecoverable.
:>
:>By the same count, I don't like the idea of Gold being used as a
:>filler material for teeth.  Unless it is removed after death, that gold
:>would be taken off "circulation".
:>
:>In either of the above cases the quantity is substantial if numbers
:>are taken into account.
:>
:>Next on the list : Gold as conductor for IC's.
:
:     At least in this last application, the gold is recoverable.  In
:fact, there are companies in operation today whose sole purpose is to
:recover gold from circuit boards.  I will certainly agree that, due to
:human superstition, it's not likely we'll be recovering gold from
:graveyards anytime soon.  However, you shouldn't underestimate our

oh yeah? this is a well established profession dating back at
least to the days of the pharohs!

:ability to get around difficult extractive problems when necessary:  If
:ever we needed it again, we would find a way to get it out of catalytic
:converters.

I'd almost bet that it would be easier to get the gold out of
the converters than from an IC chip --- those cross-linked
polymers are stuborn. How many posts show up starting with
"is there a solvent for the plastic encapsulation of an IC?"

The catalysis is, I believe, from Au METAL on exposed surfaces-
make sure the Au is reduced (a little hot H2 or CO) then leach
in aqueous NaCN....The hard part (expensive part?) is in
separating similar metals. Like Au and Pd or Rh....(should I
mention that Au use in electronics is mainly as an alloy with
another 'noble' metal (Pd or Rh) as a hardener? and that it is
difficult to economically separate the metals from the spent
plating solutions? or that said solutions get dumped, legally
and otherwise?.....Naaaaah, better not).

:     These observations are however not the reason I am posting.  I would
:like to know if anyone else thinks that Rajat's posting is silly.  (I

of course it is ... but so are most of the postings on any given
day

:tried to find a more tactful term, but I couldn't.)  First of all, I
:haven't heard that there is anything even remotely resembling a gold
:supply crisis.  Secondly, gold makes pretty jewelry, but so what?  I

You are right gold, is not really all that rare.
Pt may be more rare; it is used in converters and in jewelery
too. So the more Au used for converters the more beautiful Pt
for jewelery... about time too!

I read somewhere (Basin and Range?) that only 10% of the Au in
the Sierra Nevadas (all of Nevada?) has been recovered -- beats
me how any one arrives at such a figure. 
[Although I one saw a report, late '60s, that said we would run
out of oil by the '80s and nearly did too!]

:would rather have it play a useful technological role than see it wind
:up as a useless ornament.  Am I the only one with this sort of opinion?

Well, I agree. But let the marketplace prevail! I rather like
having a watch band that doesn't rust :-)

:
:				Marc R. Roussel
:                                mroussel@alchemy.chem.utoronto.ca


Mike