ion exchange resin flash

[WIZZARD]

Ok, this a new thread.........Hope I'm learning and not stepping on other threads.....I'm old paratrooper and landed on my head to often.

I need some stabilizing solution to use on loaded resin to keep gold/carbon leaf from forming. Like in the pic below;



When the round resin is heated abound 400F and shaken sharply flakes form, however when the heat is increased slowly to 800F. the flakes turn black and "carbon fly condition" flashes off the gold flake as the carbon goes so goes some gold. See pic below;



Notice the resin turns black and carbon can be seen on the back side. The gold in first picture is all over the resin, even creating gold leaf, however when the temperature is bumped up............flash goes the gold on the surface of the resin and the leaf.

When ignition heat of 900F is reached the the black resin turns back to gold and platinum.



My question is; What to use to stabilized the resin, before low heat, that is not sodium based?



I'm suspecting the core of the resin has Rh there and when all is ignited to NM residue and place in AR the red/brown stuff will not go into solution.

Do I elude with secret sauce, ignite, or do I find a refiner willing to stabilize first and not blow off the goodies using to much heat to soon?

I've used oxalic, thiourea and got good results; However, the OxThi solution places a lot in solution and when ignition takes place


I 've got very thin gold PGM'sslivers with the residue. I've been doing this stuff on my own without benefit of more experienced folks who may have the best answer? This stuff is to expensive to make mistakes.

WIZZARD

 

[lazersteve]

Wizz,

Why not try a water soluble salt that melts at a relatively low temperature? The salt will become molten and prevent the carbon floaters from flying away.

Once the resin is fully carbonized simply cool and wash the water soluble salt away. A low melting point metal that is readily soluble in mineral acid would be another option.

Yet another option is to heat the pregnant resin in an oxygen rich environment so as to oxidize the carbon to CO2 so it becomes a gas.

I've had the pleasure of discussing the use of Amborane resin with one of it's co-inventors in person, turns out he only lives a few miles from me! He showed me multiple vials containing the pregnant Amborane resin with the different precious metals before and after being incinerated. The various metals were all in the form of nice 1-2 mm round BB's.

We also discussed Rhodium recovery from Amborane resin and he stated it was nearly impossible to dissolve the resulting BBs once the resin was burned off and the Rh fused into BB's. I seem to remember he mentioned that the resin could be broken down with a strong acid (going from memory here) to recover the metal in a powdered form.

Lastly, you are still going to have to refine the resulting metals since they were not separated before applying the resin. The main purpose of these resins, according to my friend, is for preparing baseline standard solutions for analysis of metal bearing solutions. The expense and non-selective nature of most of the resins prevents their use as viable refining or recovery methods.

My friend gave me some Amborane a few years back, but I've never gotten around to playing with it. There is a patent in the documents section of my website detailing Amborane resin chemistry. My friend co-authored this patent. As an academic exercise I plan on demonstrating the use of Amborane on video one of these days.

In my opinion, you would be better off performing a series of selective solvent extractions if you are looking for precious metals in their pure forms.

The use of resins for recovery is very interesting, but not practical for refining from a cost perspective.

Steve

 

[Lou]

Steve, you're privileged indeed to know the inventor of that resin. I'm familiar with it as well. It would be really great if you could invite him to this board, I would love to chat with him.



I think he may try eluting it with HCl.

Alternatively, he may dry destroying the resin with nitric and sulfuric acid (wet ashing).

Alternatively, he may place it in a quartz tube and give it hell with oxygen, then chlorinate the residues in the same tube, then dissolve them as you may in HCl and chase as appropriate.

 

[Oz]

I had wondered about wet ashing with concentrated and boiling sulfuric but hesitated to suggest it as it can be so dangerous. But since it has been said I am curious as to the addition of nitric, is there something specific to this resin that requires it?

A good bonus since Rh is suspected is the sulfuric boil would be putting some of your Rh into solution while it was still in a finely divided state.

 

[lazersteve]

Steve, you're privileged indeed to know the inventor of that resin. I'm familiar with it as well. It would be really great if you could invite him to this board, I would love to chat with him.

Lou,

It's been a few months since I spoke with him last. I've told him about the forum a few times in the past, but never pushed the issue as he is very busy like most of us. He's the Executive Director of IPMI (International Precious Metals Institute).

He has a huge selection of literature on precious metals that he loans me books out of from time to time. I feel bad about stealing him away for an hour or two every six months, but it is about time for me to visit him again. With each of our visits, I learn a little more about precious metals. He is a very likable fellow and also extremely knowledgeable. He has worldwide connections in the precious metals industry and is privy to many industrial processes used by the big boys. I'm always picking his brain for new angles on PGM refining.

I think he may try eluting it with HCl.

Now that you mention it, I'm pretty certain he said concentrated HCl will do the trick.

Steve

 

[WIZZARD]

The South Africans use thiourea/weak hcl leach to elude the majority of NM except Rh and Ru. To much Hcl destroys the action of the sulfur and causes it to elementally drop out as yellow stringy paste. The residue is Rh and Ru in beads, and slight amounts of the other NM. I've use thiourea/oxalic acid and the solution is rich in metals. When the beads are soaked in stabilizing solution and cooked, a lot of the metals in the solution can be cemented out and rest of the goodies can be locked up in the residue, so eluding to it's end point first and roast the rest?

Sometimes the loading is mostly PM.



WIZZARD

 

[Lou]

I really just want to incinerate it. I've run too many columns in my life :-(


Thanks for the details Steve. It'd be a real pleasure to talk to that fellow some time!



Lou

 

[WIZZARD]

Hey,
Thanks to all who made input.

Using oxidizers on the loaded resin is not a good idea in a column, as a good deal of reaction takes place. Not a Amborane product.

http://www.dow.com/PublishedLiterature/dh_0030/0901b80380030fc4.pdf?filepath=liquidseps/pdfs/noreg/016-00004.pdf&fromPage=GetDoc

WIZZARD

 

[goldsilverpro]

I used to assay the resins by wet ashing with H2SO4/HNO3. At the time, there was a lot of discussion about maybe processing the jobs in this way, but I don't think I would want to do a large batch - 300-500 degree F H2SO4, in large quantities, is not my cup of tea. Also, when the HNO3 is added to the hot H2SO4, in very small quantities, to get rid of that last bit of carbon, it pops and cracks and creates little explosions. I guess you could do it at a lower temperature, but I would think it would take forever.

So we ended up incinerating the resin, even though we knew there were losses. We did put in some stop-gaps to minimize the losses, but there was always some that was lost. I'm thinking a common way that people incinerate resins is slowly in a crucible in a box-furnace with a little air coming in and occasional stirring. About the only thing that smells as evil as burning resin is burning x-ray film emulsion.

In the job-shop refinery, we received different brands of resins and we usually had no idea of who made them. Also, the resin was usually dried out and cracked. We tried several elution methods without much luck. We could elute some of it but not all of it. I'm thinking that, to get the best efficiency with gold, you should first elute the other metals with different eluents. I also seem to remember that HCl/acetone is a fairly common eluent for gold, at least with certain resins.

We also tried aqua regia. What a mess. Usually, the resins we ran were from cyanide operations and still had dried cyanide salts in them. Upon the introduction of the AR, some of the gold was immediately converted to AuCN, a canary yellow salt, insoluble in acids, that coated everything.

 

[WIZZARD]

Leaching, selective dropping, chemical mess the whole way, however stabilizing the resin with just enough solution to wet the resin, then ignite in several stages, then go wet, using conditioner to keep in closed circuit, sounds like a good way to go. I'm still not happy with doing either way, I was hoping for the secret sauce.
I found the SA's paper, they used acetone, but found the thio/hcl was working with the resin they used. It may be different with each as there are resins for a lot of applications.


http://www.saimm.co.za/Journal/v104n06p323.pdf


WIZZARD