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Chemistry Forums for Students => Inorganic Chemistry Forum => Topic started by: WorkingWithPGMs on November 15, 2008, 06:48:39 PM

Title: Au NaCn plating gel leftovers.
Post by: WorkingWithPGMs on November 15, 2008, 06:48:39 PM
Hi,
I'm trying to help a buddy recover his leftover Gold Plating Gel from his big dream days of taking on the local auto dealers and working for himself by custom plating on their lots.  It was harder to break into than he thought.  He sold the rectifier, but kept the 24K purple gel, that says right on the contain: caution Poison Cyanide.  He believes it at least 3 grams of Au.

Well, I've been working with it all day, and the stuff wont' dilute in warm water.
It looks clear when I 3:1 volumetrically with Distilled, but I go to strip it out by running it through a carbon column and it just gels back up again in a matter of minutes.

What IS that stuff?  Should I be trying an isopropyl or something else to try to break those gel type bonding.  It's not goey, and is quite cool to the touch when gently wringing out the filter.

I don't want to incinerate it if I don't have to.  What say you guys.
Thanks for your help.  I really get in trouble trying to help out buddies.  :-[

M.D.
Title: Re: Au NaCn plating gel leftovers.
Post by: macman104 on November 15, 2008, 07:25:39 PM
I don't have any advice for the actual processing, but please please be careful!  Cyanide is no joke.
Title: Re: Au NaCn plating gel leftovers.
Post by: WorkingWithPGMs on November 15, 2008, 09:56:12 PM
Thank you macman for your concern. 

I'm not shifting PH, and am wearing all safety gear, as is my custom.

Is demanufacturing a semi-solid gel a verbooten topic on this forum?  If so, apologies to all.  I'll go to the proper topic if required.

I'm just trying to help my buddy out by giving him back a portion of his money
he's lost, that's all.
Title: Re: Au NaCn plating gel leftovers.
Post by: Borek on November 16, 2008, 04:17:20 AM
Is demanufacturing a semi-solid gel a verbooten topic on this forum?

No problem so far.
Title: Re: Au NaCn plating gel leftovers.
Post by: Arkcon on November 16, 2008, 10:04:04 AM
Just re-sell it.  You're not going to get more gold out of it, quantitatively*, than there is in it, plus the value of this gel and it's cyanide content.  Could you, instead of incinerating it, just plate the gold out onto a carbon rod?  If you really need to see the lump of gold, that is.

*Quantitatively, in this sense, means you will lose some in the manipulations.
Title: Re: Au NaCn plating gel leftovers.
Post by: WorkingWithPGMs on November 16, 2008, 01:18:32 PM
Thanks, Arkcon for your time in replying.  This is a gel he's already broken the neckseal on, so it would be hard to resell.  He's tried.

He showed me the paperwork on it from the old manufacturer he got it from way back when.  It has close to 1 troy oz of gold in it to be recovered. 

As I said earlier, I'm not afraid of the cyanide, as it can be neutralized with NaOCl, same as has been done for centuries of laboratory types such as you guys and gals are.

As this is old stock, his cost basis is so low, he would owe capital gains on it by selling it outright.  He wants to keep the gold, and wants me to cast it for him into something his wife can wear as a Christmas present.  We are kicking around some designs, but hasn't settled on anything until I get the gold out, and can weigh it for him to make his final choice.

Thanks again for the responses.  I'm still looking for help here, guys & gals.
Title: Re: Au NaCn plating gel leftovers.
Post by: Borek on November 16, 2008, 02:34:13 PM
I wonder if adding iron fillings will not reduce gold.. Then you will have to filter the solid, dissolve excess iron in HCl and you are left with gold.
Title: Re: Au NaCn plating gel leftovers.
Post by: WorkingWithPGMs on November 16, 2008, 08:10:19 PM
Thanks, Borek for continuing to think about this.  FeSO4 will ppt it, true.  But I can't get the darned gel to yield the values so I can ppt.

I finally figured out one of those online image host dealies.  This is my first try to
load a pix on the forum.  Please be patient with me:
(https://www.chemicalforums.com/proxy.php?request=http%3A%2F%2Fimg222.imageshack.us%2Fimg222%2F9827%2Fleftoverbsvd9.gif&hash=b934fec405c96482fad9b41c2b33f740dce5bed9)

Does this help any?
Title: Re: Au NaCn plating gel leftovers.
Post by: nj_bartel on November 16, 2008, 09:16:41 PM
Any idea what type of gel it is?  Maybe THF would work as a solvent?
Title: Re: Au NaCn plating gel leftovers.
Post by: Borek on November 17, 2008, 05:00:51 AM
FeSO4 will ppt it, true.

I mean metallic iron, not sulfate. Chances are iron will not only reduce gold, but also bond cyanide.

How should the gel be used for plating? Do you know any recipe?