Dried Cyanide Plating Solution

[JacobsMetals]

I recently got a brush plating machine for production and received various solutions along with it. One solution had dried out into a fine yellow powder with a similar consistency of Portland cement and from my research in it's original liquid state it's a cyanide gold solution (guess when it was originally manufactured poison labels were the only requirement and not a specific toxin label/active ingredient). My assumption would be the powder is in fact gold in some type of compound (presumably cyanide) but it doesn't have the colouration I'd expect. Also the liquid is a semi translucent black (received 2 bottles of this particular solution). Curious what the community thinks as far as it being gold as well as how to process it into metallic gold.

 

[Lino1406]

Yellow powder can be palladium cyanide. Initially, check pH by dissolving a sample in water (does it readily dissolve?). When you answer we can continue

 

[anachronism]

Perfect answer by Lino- pH tester is your friend with Cynanides.

 

[JacobsMetals]

I added the water previously and it was effectively murky with a tinge of yellow water with standard pH, no acidity. The powder didn't want to dissolve but with some agitation it broke apart and spread evenly through the water.

 

[Lino1406]

Your description fits palladium cyanide solution in ammoniak, which vaporized. For final confirmation dissolving a small amount in aqua regia and testing with Dimethyl glioxime solution is required. If positive (yellow), we'll continue to recovery

 

[JacobsMetals]

Unfortunately I don't have the setup to make AR. My ventilation isn't designed to run nitric so I'm sticking to AP solution at the moment. Also wouldn't there be gold compounds in the powder as well? Ideally gold cyanide since the solution is 24k gold. I believe the palladium would settle to the bottom instead of dissolving with any gold compounds in hcl+cl solution but I'm not sure how gold cyanide functions in a chloride solution as far as if SMB would break it down to gold and sodium cyanide. Also could be wrong of course but I thought palladium isn't affected by the chloride solution.

 

[anachronism]

Question. Given that you don't know what it is or how to process it, how do you make assumptions the way you do? Lino really does know his beans.

Do some really in depth research here and then ask for clarification on the points rather than make assumptions because you can end up in a real mess- especially if you're playing with cyanides.

 

[JacobsMetals]

I know a little bit about the solution as far as it has 24k gold cyanide. The rest is a mystery since it's a patented solution and they don't share it's ingredient list. I trust Lino's information and my question about adding the powder to a chloride solution was just a question. I'm not intending to toss it in and hope for the best but looking for more information as to what I can do with my current equipment. And for the palladium not reacting it's information from another post on here. Not sure about it's validity though of course because I only seen one or two people mention it.

 

[anachronism]

I hear you.

To correct you on one point though.

You mentioned not using Nitric because you don't have a fume cabinet. The tiny amount of nitric you would need to test Lino's theory would produce far far less NOX than the Chlorine you are using with your acid/bleach process and believe me when I say that you're no better working with Chlorine than you are NOX.

Food for thought. 8)

Jon

 

[JacobsMetals]

Fair point on the quantity Jon. If I can find a distributor around me then I could look into making a small batch of AR for testing but at the moment my closest known distributor with somewhat realistic quantities (current chem distributor I actually use does bulk semi deliveries of 55 or more gallons and im not looking to buy an industrial amount of nitric) is about a days drive. Now that's advertised chemical shops so there might be more closer that's not advertised or just hard to find on the internet. Not too worried about rushing through anything because I have other projects I'm more experienced with so I can try to hunt down a shop or order the items online while I work on them. I have a purge ventilator so chlorine isn't an issue but nitric would be rougher to cycle in a decent manner in bigger quantities. Basically ventilation kicks on when you hit a button to clear the building so chlorine doesn't seem to be as much of an issue as nitric when it gets going. Or at least I'm more comfortable working with the chlorine.

 

[snoman701]

Won't the treatment of ammonia based cyanide with chlorine release chloramine gas?

 

[snoman701]

And can't you just direct melt cyanides?

 

[JacobsMetals]

You're right about the chloramine snoman. Didn't think about that but yeah as long as there's some remaining ammonia (don't think there would be because it'd have to be ammonium cyanide and it shouldn't be able to form, ammonia on its own evaporates completely and I started with a dry powder) it'd react. Also good question on the straight to flame! It'd break down any nasty stuff and then it could be refined as long as cyanide compounds can break down. Only found one person mention cyanide in their burns and they weren't talking about specifically gold or palladium cyanide but rather sodium cyanide left in the gold powder during incineration of a filter.

 

[nickvc]

I believe the high karat testing solutions are basically AR and are available in small quantities, something most refiners should have for testing materials.

 

[JacobsMetals]

The testing kits, specifically 22k gold is AR but not perfect so it doesn't dissolve pure 24k gold. Don't know how much it would matter for testing palladium but ideally I'd think you'd want the right mix since a little off changes how it affects the gold.

 

[JacobsMetals]

Update: I believe the powder is AuCN. Matches characteristics and goes along with the possible ammonia solution. Also talked to a rep and they went for the sale but acted like I wasn't off. Still getting back into all the chemistry but I'm pretty sure it's AuCN and I should be able to decompose the powder into pure gold along with cyanogen gas. I'll still see about testing with stannous but realistically I should be able to go straight to melting at this point. Also I do have a little Pd now from the diabetic test strips I use but Pd is out of my melt range so it'll sit as powder and leaf till I find someone with the proper equipment. Also AuCN will sit since I can add waste from liquid solution to it and build up a nice quantity over time.
Update part 2: went ahead and fired the powder up. Got the gold out but final batch blew my melt dish in half. Looks like cheap melt dishes aren't up to par. Had visible impurities in the dish that didn't take well to the heating and put too much stress on the dish.