# Catalytic converter testing questions



## skippy (Apr 3, 2010)

Hi everybody, I thought I'd establish this thread to ask questions as they arise while I try different processes on catalytic converters. Right now I am experimenting with AR and trying to interpret stannous tests.
The stannous tests below are from treating a large GM cat, short bread loaf style. 




This cat has two honeycombs, one large and one small. The one on the right from the bigger comb, and the one on the left is from the smaller comb.
A small sample of the smaller comb was treated with hot aqua regia and the solution developed a nice rich red brown color. I then stannous tested the solution. The top end was dipped into the concentrated extraction solution and then tested and the bottom was dipped into the same extraction solution diluted maybe 10 to 1 then tested. On the diluted q tip there appears to be palladium from the green color. There's also a rosey, peachy red sort of color too that I am unsure of the meaning. On the concentrated spot on the top end there is a dark center surrounded by a band of very rich red with a yellow sort of periphery. I also treated a sample of the small honeycomb material with straight HCl and you can see the results of stannousing the concentrated and diluted hcl extraction liquor in the photo with the lone q tip. The one end is a solid extemely dark blue brown, and the other has orangy brown stripes with a blue tip.





In the first picture, on the right are test swabs from the bigger comb. The bigger comb's washcoat was very light in color compared with the smaller comb. When treated with hot AR the solution only evolved a mild yellow hue. The bottom end ofthe q tip was the test from treating the comb sample with the AR, and the top end was from soaking another sample of the same comb in straight HCl. They both look the same, and to me they both appear to be positive for platinum! They are very similar in intensity. Does this make any sense? Does the AR that is still in the q-tip interfere with proper platinum stannous testing? Could it be that my HCl has or develops enough free chlorine to dissolve some platinum? I wouldn't think so, especially because the soak was around room temperature - is this some sort of false positive result? I'll likely do each whole comb in AR and then cement, redissolve and precipitate the metals to get a definitive answer to what is in these honeycombs, but I was hoping someone might be able to help me interpret these stannous tests.


Thanks, and I hope this is interesting to the vets, and educational for us novices.


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## lazersteve (Apr 3, 2010)

The orange/red colors indicate Platinum. 

The brown and blue-green is Pd. 

HCl will dissolve Pd when it has been oxidized (like in a used cat).

Steve


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## skippy (Apr 10, 2010)

Thanks Steve, I've got some DMG coming too, that should help me do my testing. I still don't understand why a straight HCl soak of honeycomb (no chlorine, no peroxide, no nitric, nothing) apparently put platinum into solution.


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## Oz (Apr 10, 2010)

skippy said:


> I still don't understand why a straight HCl soak of honeycomb (no chlorine, no peroxide, no nitric, nothing) apparently put platinum into solution.



I have mentioned this before and most discount it because conventional wisdom is that HCl will not dissolve metallic Au, Pt, or Pd without an oxidizer present. Plain old exposure to air will provide the oxygen over time. Stirring and/or boiling expedites this process. I shudder to think of all the PMs lost because all are so sure HCl will not dissolve them that they fail to take a simple stannic test before discarding solutions.


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## skippy (Apr 10, 2010)

Thanks, Oz, I'm certainly inclined to believe it now. I wonder, though, if there isn't something about the monolith, either physically or chemically that helps oxidize some of the HCL into free chlorine.


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## Oz (Apr 10, 2010)

As Steve said, HCl will dissolve PdO. When it does, where does the “O” go? It may not be entirely consumed in the digestion of the Pd. 

I have left metallic Pd in the dilute HCl used to wash it and found that a good portion can go back into solution depending on the length of time.


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## lazersteve (Apr 10, 2010)

skippy said:


> Thanks, Oz, I'm certainly inclined to believe it now. I wonder, though, if there isn't something about the monolith, either physically or chemically that helps oxidize some of the HCL into free chlorine.



Skippy,

Platinum and Palladium are both known for their ability to absorb Hydrogen. Perhaps the Pd or Pt acts to remove the H from the HCl, leaving the Chlorine free to react with more of the metal? 

Steve


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## skippy (Apr 11, 2010)

Yes, seems like that might be possible Steve, I don't know. I've also read something about cerium oxide in the catalyst material being an oxygen donor under certain conditions - I don't know what conditions those are that it absorbs and releases oxygen under. 

Anyhow on to my next experiment. I put some honeycomb in a test tube capped with a piece of ptfe, with concentrated sulfuric acid and heated it up ultimately to around 315 degrees C for three hours. After the reaction the honeycomb was slightly mushy and caked with the sulfates of the heavily attacked ceramic honeycomb. I leached the material with HCl and got a palladium rich solution. I am currently trying an AR leach to see if there is anything left, and it appears the sulfuric acid got the vast majority of the palladium! Nice! This brings me to my next question. I'm concerned that the Rhodium that I may have dissolved may autoprecipitate if the leach isn't at a certain pH or contains certain ions or whatever. Is there a right way to leach this sulfuric acid roasted material? Or if anyone could tell me how they leach bisulfate fusions, that might be close enough too. Thanks everybody for all the help so far, I think I'm learning a lot!


Edit: I looked a little more and I found something on leaching the bisulfate material with diluted HCl ( 1:4) - it seems like a good place to start, but if anyone has any other ideas I'd love to hear them.


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## butcher (Apr 11, 2010)

Rh after sodium bisulfate fusion is water soluble, the is how they remove it from Os,Ru,Ir, these along with Rh are usually not soluble in aqua regia. after Rh and sodium bisulfite fusion the Rh is washed (soluble)from the insoluble residue.

Rh should be soluble in the concentrated sulfuric hot, but filtering may prove difficult (I wonder how a fiberglass wad in a funnel would work?)


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## skippy (Apr 19, 2010)

Thanks Butcher good to know that about the fusion, also interesting idea on filtering the acid hot. I didn't know that the Rhodium drops out again once the sulfuric cools? I could believe that, can anyone confirm?

I got my DMG in the mail, and I tested some of my cat extraction fluids, and I confirmed that the positive stannous test for platinum was not a misreading of the test - there was no palladium in solution, so it must be 
platinum in solution, so it's confirmed consumer grade HCl can sometimes put at least some platinum into solution!


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## Oz (Apr 19, 2010)

Just as you need to test your stannic acid against a standard solution of gold before using it and trusting the results, you should do the same with DMG against a palladium standard solution before trusting results.


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## skippy (Apr 20, 2010)

Good point Oz - I'll be going seat of the pants until I isolate some palladium and make solutions though
In this case I'm quite certain I'm right though - my straight HCl leach that I suspected contained only platinum had no reaction, no haze, no precipitate upon testing with my dmg and it turned 
bright orange from a stannous test. I tested the same DMG solution on a sample I believed contained palladium and sure enough: voluminous yellow precipitate.


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## Oz (Apr 20, 2010)

skippy said:


> I tested the same DMG solution on a sample I believed contained palladium and sure enough: voluminous yellow precipitate.



In that case you have proven your DMG. It does not require a pure element standard solution any more than stannic does (although there are advantages at times).

I was just concerned that you would rule out Pd being present when it may have in fact been present, you could have had a faulty DMG testing solution.


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## skippy (Jan 21, 2011)

I just thought I would add a bit of knowledge to my thread. I had read some suggestions that the first brick in a two brick (dual bed) converter would have all the rhodium in it. I was hoping it might be possible to easily segregate rhodium containing combs from pt and pd only combs, but I don't think that's the case. After taking samples off the two bricks in one cat, I found Rh in both. I attacked the samples separately in boiling concentrated sulfuric in test tubes for 15 minutes, diluted and filtered, and then treated with DMG to precipitate the palladium. Both samples when tested with stannous indicated with a pinky purple color. I'm pretty confident that there was no palladium confusing the stannous because every other stannous test that had palladium in it I have done I was able to produce different colors by the dillution of the solution (greens blues and browns). Dilution this time only varied from a darker purple to a lighter pink.



If anyone feels like testing this too, it doesn't take too long, but be careful though, as I shudder at what the boiling concentrated acid would do to flesh. Keep the sample size and acid very small to avoid bumping! I put only about as much crushed sample in height as the diameter of the test tube, and I had no serious bumping. The converter material becomes more sludgy during the attack, and if you heated too thick a sample in your test tube it might burp or bump hot acid right out, where you dont want it!!! I put a piece of glass wool in the tube a little above the sample and acid. This worked to keep the heat in and most of the fumes out. Gloves, face shield, outdoors etc. 

I would be glad if anyone with more experience with stannous tests to confirm my results on this. I might try it again with a couple other cats just to be sure.


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## Platdigger (Jan 21, 2011)

I wouldn't be suprised if some of the rh migrates through out both combs with use.


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## skippy (Jan 22, 2011)

Platdigger, I wouldn't be surprised if that happened to some extent either.


However , from what I've just been reading though, in addition to Rhodium being good at reducing nitrogen oxides, it's also a good oxidation catalyst too, and works even when the platinum and palladium are being poisoned by some sulfur dioxide in the exhaust. So there is a possible reason to put Rhodium downstream.


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## arthur kierski (Jan 25, 2011)

i am startled by skippys ease in obtaining rh from cat powder with hot concentrated h2so4 by boiling the powder for 15minutes.
i did extraction of pgms from cats for 10 years and in the various process used,i had extremelly dificulties in obtaining the rhodium.
In deciding to do pgms extraction again( because of the high prices of pt ,rh and pd) i came across this thread---and tomorrow i will try to do the sulfuric experience with 1kilo of cats powder to see what happens----
it is not arrogance,but learning----i am re-reading all threads written in the forum relating to pgms extraction from cats----
thanks for any comentaries 
Arthur


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## skippy (Jan 25, 2011)

Arthur, it may have been longer than 15 minutes, but no longer than 25. I should have timed it. I need to be more scientific and methodical with my attempts. One thing I can note about the boiling was that I boiled it strongly enough to really agitate the powder, and I rolled the test tube about while it was heated to assist with this agitation. It may be tricky to get that sort of action going with a larger sample.


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## skippy (Jan 25, 2011)

Be careful Arthur with scaling up like that. You are working on a scale about 100X what I did, and any dangers are likewise multiplied.

I would also add that on my first attempt at this test, I had preleached the sample with nitric to get the palladium out, and then proceeded with sulfuric. I didn't get any rhodium in solution, I suspect because the catalyst had extra water in after draining off the nitric. I knew that water would interfere, but I expected the water would boil out, but it didn't, at least not in the time I gave for the boiling. So make sure your sulfuric starts concentrated.


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## arthur kierski (Jan 25, 2011)

thanks skippy,i will try and then tell you the result obtained-----it is very important to me because before , i extracted pt,pd and rh (parcially)with ar,and the rest of rh left in the spent powder with a sodium bisulfate fusion and hot water----thanks
Arthur


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## lazersteve (Jan 25, 2011)

Arthur,

Here's the color you are looking for (or darker):







Scaling up will be a challenge, please be very careful as your input to the forum and your health are very valuable to me.

Steve


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## arthur kierski (Jan 26, 2011)

thanks steve for your concern and worries----i will do the scalling up with great care --------i tried many times to boil for hours rh containing powder with hot conc h2so4 and did not obtain positive results---that is why i was so surprised with skippys experiment----
i will think a bit more before doing the experiment-----


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## skippy (Jan 26, 2011)

Here's some pics of the stannous tests, I'm not quite happy how either picture captures the color, but it's close enough. Pinky orange salmon.

The first pic washed out the colors too much the second puts too much red in it.


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## skippy (Jan 26, 2011)

Steve, my sulfuric acid didn't look like that. I don't think there was enough dissolved or even dissolvable to give a real noticeable color to the sulfuric itself. I didn't notice any real color to the sulfuric post reaction. After dilluting and filtering, and treating with dmg, the solution was yellow.


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## lazersteve (Jan 26, 2011)

Skippy,

Please put a small sample of your solution in a test tube and follow the procedure outlined here:

Rhodium Stannous Chloride Test

Please post a photo of your test results, one of the solution color before and one after the test solution has cooled. It would be especially helpful if you have DMG on hand and remove any Pd before you try the test. Watch carefully for the initial lightening of the color of the solution, followed buy the scarlet color appearing after the solution cools.

Another second test to determine if your sulfate has Rh present is to bring the pH up over 8 using drop wise additions of NH4OH (ammonium hydroxide 10% works) and see what color the precipitate is. You can perform this test on small test tube sample as well.

I'm looking forward to seeing your test results.

Steve


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## lazersteve (Jan 26, 2011)

skippy said:


> .. After dilluting and filtering, and treating with dmg, the solution was yellow.



Sounds suspiciously like Palladium (Pd) to me.

Steve


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## skippy (Jan 26, 2011)

Steve, I treated both with DMG. One of my test solutions yielded the flocculent precipitate, the other nothing. Both solutions post dmg finished the same similar very light yellow color, which is also the same color as pre DMG. I say the color is due to iron. The sulfuric attacks the cordierite quite a bit at the high temp. 
I will have to try the procedure you linked to next time, my thanks.


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## lazersteve (Jan 26, 2011)

skippy said:


> I say the color is due to iron.



That is a likely candidate with cats.

Steve


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## skippy (Mar 21, 2011)

I thought I would add, that I know have seen rhodium's effect on stannous enough now to recognize it and I stand by my results here. 
Boiling concentrated sulfuric acid works well to test for rhodium in cat comb.


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## skippy (Apr 5, 2011)

Recently I had extracted some cat material I am certain only contains platinum. I thought I would try to test the AR solution with stannous and it had no reaction. Often times before I have been able to get a stannous indication from a AR solution with nitric left. This time I got a negative from the stannous test, but I then took a small amount of the solution, and added a piece of copper wire to it. At the interface of the solution and the wire I could see a fine black precipitate that eddied off the copper, and the black precipitate was carried scarcely any distance from the copper before it dissolved again. It was neat to watch. 

It suggest to me that very fine platinum seems to dissolve very readily in room temperature AR, which I did not know!
This brings me to a question, sometimes I am inclined to do my stannous testing on the fly right while the AR is still working on the material. My latest experience indicate that
taking a stannous test of an active AR solution is pretty unreliable , so I am wondering if I can take a sample of such an AR solution, add urea, and get a better indication.

*edit* ignore the first part, I believe now the black powder was just fine copper abraded by the acid rather than a precipitate and the solution was in fact quite as barren as the stannous originally indicated. 
still wondering if urea can be used to fix a AR sample for stannous testing though


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## bubba (Apr 9, 2011)

Skippy, I am not sure what your goals with this are, but with 15 years in the cat business, I can tell you that many, including ourselves, have hit a wall when it comes to a wet chemical process and catalytics. The problem is Rh. The best recovery we could come up with on Rh was about 85%, which is a quick way to go out of business. We cut 10,000 plus units a month, and at the end of the day, there is no way to compete with a plasma arc furnace, when you do the numbers.


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## skippy (Apr 9, 2011)

I'm sure there is a great deal of truth to what you are saying Bubba. I don't know what efficiency numbers a plasma furnace has, I recall reading 89% efficiency, but I'm sure the operators can do better if they run it hotter or longer or what have you. 95? 99? 99.9% I don't know.

You extracted 85% of the rhodium - say Rhodium is 25% of the catalytic $ value .15*25%=%3.75
I'm shocked that missing out on that little would render the activity unprofitable. Did you refine the ceramic yourself or send it out? Everyone here would appreciate a description of the leach process if you were doing it yourself. I think a lot of people here would be very happy with 85% of the Rhodium. 

My goals? At one time I was sure that processing cats was a path to wealth, now I'm quite certain that it's no way to get rich quick, that is for sure. For me sulfuric acid turned out to be a good way to test for presence of Rhodium in situ. I wanted to share that because I thought it was very useful. I don't know the best way. I try some things, do some testing see what happens. I find it interesting, but if I was a hard nosed businessman, I would likely be applying myself elsewhere by now.


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## bubba (Apr 10, 2011)

skippy said:


> I'm sure there is a great deal of truth to what you are saying Bubba. I don't know what efficiency numbers a plasma furnace has, I recall reading 89% efficiency, but I'm sure the operators can do better if they run it hotter or longer or what have you. 95? 99? 99.9% I don't know.
> 
> You extracted 85% of the rhodium - say Rhodium is 25% of the catalytic $ value .15*25%=%3.75
> I'm shocked that missing out on that little would render the activity unprofitable. Did you refine the ceramic yourself or send it out? Everyone here would appreciate a description of the leach process if you were doing it yourself. I think a lot of people here would be very happy with 85% of the Rhodium.
> ...



Ok Skippy, now nobody ever listens to me on this, they all have visions of getting rich leaching cats in their back yard, the reality is something all together different.
Processors like us, work on margins of 5-8%, thats it. If you only recover 85% of the Rh., and you are working on margins of 8% max., which you will have to do if you are going to do any volume, and a smelter is out there recovering 98%, you are out of the money before you ever start. 
So if you want to be in the converter business you have a few options
1. Spend 10-25 million dollars on a plasma arc furnace. You will also need another 50 million dollars to operate your trading desk.
Or
2. Get 2 or 3 million dollars together and get a refining contract from a major smelter, and start cutting converters. You will need about 5,000 units a month minimum to make that work. This is where we are, and we cut 10,000 - 12,000 units a month.
Or
3. And this is the most practical approach, establish a route, go around to muffler shops and wrecking yards and collect cats. Learn all you can about the various grades of converters, last time I looked I think we have over fifty grades, meaning 50 different prices. Find a good processor that you trust, that pays and grades fairly.
If you don't have the resources to do #1 or #2, then you are "pissing into the wind" so to speak if you try to do anything other than #3.
I learned all of these things the hard way, we tried at least 2 dozen leach formulas on catalytics back in the early 90's, none did a good enough job on Rh., and all of them generated too much Haz-mat waste. Now this is the point in my story, when most people who are at the point you are at Skippy, decide that they will find that missing link that we could not find and they go back to the drawing board and waste a bunch more chemicals and cats. Then after about another six months or so, I get a call or email from them wanting to sell us their whole converters. I hope this was helpful. andy. www.westerncatalyst.com


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## skippy (Apr 10, 2011)

Anything from someone who has as much experience as you is valued. If you don't mind, at your level how do you get paid on PGM by the plasma furnace operator? IE what percentage, on assay or recovered etc.


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## bubba (Apr 10, 2011)

skippy said:


> Anything from someone who has as much experience as you is valued. If you don't mind, at your level how do you get paid on PGM by the plasma furnace operator? IE what percentage, on assay or recovered etc.


 
That depends on how you take your money. It take 3 months for platinum to "turn out" meaning completion of the refining process. So, what that means is that once you ship, the clock starts, and their are 115 separate steps, to produce pure platinum, certain steps require time in between the next step to allow chemical reactions to occur. That is the reason for the 90 days required to make hallmark metal. 
So if you need what is called "quick money" you can get paid on assay, my assays usually come back about three weeks after our shipment hits the smelter. Because you are getting paid on an assay and not a solid commodity, you are going to be charged a lease rate. This is interest on the refineries money, and it is calculated on the time period it takes for the metal to turn out. 
If you have deep pockets you can wait the three months, and not be charged a lease rate.
As far as returns, We can pay you 90% of assay on Pt. Pl., and Rh. with a minimum lot size of 2,000 lbs. of catalyst, this translates into 1,000 average cats, and we will de-can the units if necessary, for $0.50 per unit.
Unless you do huge volume 90% would be hard to beat, and this is a net return, no assay charges or per pound processing charges. Lease rates would apply if you would require quick money. andy. http://www.westerncatalyst.com


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## skippy (Apr 10, 2011)

So the plasma operator is obviously giving you better than 90% of the assay value. That is indeed nearly impossible to compete with on a small scale for sure. 
No doubt your information will save many people grief. 

Thanks Andy.


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## skippy (Apr 10, 2011)

Sorry Andy, can't help but ask more questions. What is the per pound fee and batch fees that you pay? I ask because I read talk about doing an acid leach and selling the residue to the plasma operation. This would allow someone to accumulate ceramic volume while having less money tied up. 

Tom


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## lazersteve (Apr 10, 2011)

Bubba,

Have you tried gas phase extraction of the comb material?

Steve


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## Lou (Apr 10, 2011)

Andy,

*Let me emphatically clear on something here: it does NOT take 3 month for platinum to be refined.* Perhaps to get 100% accountability, but even then, that's a serious, serious stretch. There aren't 115 separate steps if the burden is just Pt, Pd, Rh and fairly simple base metals like from auto catalyst. Iridium takes the longest of all the platinum group metals, and there's some new info on refining it that will be disclosed next year in the literature.

No, what's happening here (in my opinion) is that they're making money on your money. By this I mean, they're purposely delaying payment to have a greater cash stock in their own right. 

You're a couple steps down from where the platinum is going. It goes to the smelter, who's the true reclaimer, then it goes to the smelter's refiner (whoever has that largish contract), then either the refiner sells it as pure metal or makes something worth more out of it.



Edited my post to reflect Bubba's actual words.


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## bubba (Apr 10, 2011)

skippy said:


> Sorry Andy, can't help but ask more questions. What is the per pound fee and batch fees that you pay? I ask because I read talk about doing an acid leach and selling the residue to the plasma operation. This would allow someone to accumulate ceramic volume while having less money tied up.
> 
> Tom



Well, every refining contract is different, it all comes down to how much volume you do, and what you can negotiate.
On your residue, I am going to say it will run maybe $5.00 a pound in values if you have run a mix of material and done a fair job of leaching.
We have been down this road, the proper handling of the haz-mat waste kills the profitability of this type of operation.
At any rate, we could assay you material in house and quote it.
My question is where is your market for your precipitate, what kind of returns have you been quoted? If you have less than 100 oz. lots, I am going to bet they won't pay more than 90% for the precips, that makes your whole recovery plan unprofitable.


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## bubba (Apr 10, 2011)

Lou said:


> Andy,
> 
> *Let me emphatically clear on something here: it does NOT take 3 month for platinum to be refined.* Perhaps to get 100% accountability, but even then, that's a serious, serious stretch. There aren't 115 separate steps if the burden is just Pt, Pd, Rh and fairly simple base metals like from auto catalyst. Also, it doesn't take 90 days to get an assay. I can get Pd, Pt, Ir, Rh, Ru, Au, and Ag assayed in under a week from the people I contract with, and probably quicker if I hound them. It doesn't even take 3 months to refine rhodium. Iridium takes the longest of all the platinum group metals, and there's some new info on refining it that will be disclosed next year in the literature.
> 
> ...


 
Sure. Everyone I meet knows more about this business than I do. Even the guy with a pickup truck that brings me 10 converters at time. I am used to it. And I never said it take 90 days to do an assay, we assay in house everything before it leaves our dock.


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## bubba (Apr 10, 2011)

lazersteve said:


> Bubba,
> 
> Have you tried gas phase extraction of the comb material?
> 
> Steve


 Steve,
I have never heard of this process, we gave up on extracting/high-grading years ago. Their are some very clever people out there, and I don't want to discourage them from coming up with a better mouse trap, its just you need to ask yourself a simple question.......
Why would a refiner spend 10, 20, 25 million dollars on a smelter, if they could just use a wet chemical process with an install cost of maybe a couple of hundred thousand dollars? The short answer is efficiency, and you will find after you burn up alot of money, that your time is better spent buying/collecting more material than it is trying to pull metals yourself. andy.


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## lazersteve (Apr 10, 2011)

Bubba,

What method do you use to assay the combs?

Steve


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## skippy (Apr 10, 2011)

Andy, I don't have a recovery plan, and I have no business model. My stock of catalyst I experiment on would only cover an assay maybe.
I was hoping you could share with me, and with the forum what terms the plasma guys give you (per weight fees, batch fees, percentage paid) in order to help everyone here understand the business better, as I don't think it's been discussed before. 

As far as the stupid, foolish hopelessness of what I do  , I mean to process the material myself, and otherwise the business doesn't really interest me.

Tom


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## bubba (Apr 10, 2011)

lazersteve said:


> Bubba,
> 
> What method do you use to assay the combs?
> 
> Steve



Fire assay / I.C.P


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## bubba (Apr 10, 2011)

skippy said:


> Andy, I don't have a recovery plan, and I have no business model. My stock of catalyst I experiment on would only cover an assay maybe.
> I was hoping you could share with me, and with the forum what terms the plasma guys give you (per weight fees, batch fees, percentage paid) in order to help everyone here understand the business better, as I don't think it's been discussed before.
> 
> As far as the stupid, foolish hopelessness of what I do  , I mean to process the material myself, and otherwise the business doesn't really interest me.
> ...


 
The details of my refining contract are proprietary information, no two are alike, if I want to keep it, I should keep the details to myself. some things are not meant for public forums. 

As far as your stupid foolishness, Lol, hey,I have been there.


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## qst42know (Apr 10, 2011)

Would you mind describing your fire assay methods, collector metal, flux recipe, furnace temp, etc., or is that proprietary?


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## bubba (Apr 10, 2011)

qst42know said:


> Would you mind describing your fire assay methods, collector metal, flux recipe, etc., or is that proprietary?



we use gold as a collector, the flux is a pgm mix that we came up with using the primary from action mining. it is a must to use pre-glazed crucilbles when assaying platinum.


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## Platdigger (Apr 10, 2011)

PM sent


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## Lou (Apr 11, 2011)

bubba said:


> Sure. Everyone I meet knows more about this business than I do. Even the guy with a pickup truck that brings me 10 converters at time. I am used to it. And I never said it take 90 days to do an assay, we assay in house everything before it leaves our dock.



Either I misread what you wrote, you misread what I wrote, or as seems likely, both happened. Sorry if I came across condescendingly, that wasn't my intention. I didn't read your post slow enough to realize what you were saying. Please clarify your post, particularly your claims on the refining.

And I certainly misquoted you, my apologies. You said about 3 weeks on an assay. It can take that long third party, especially if you go through a reputable house that has a backlog of assays from very big customers. I'll edit my post to reflect that. 

I don't claim to be an expert about catalytic converter brokering or plasma melting, and I don't know your business--it's not my business, I'm not in the brokering/reclamation arena. I don't claim to be an expert in anything, actually. 

Also, the gas phase method is not an aqueous method, hence the gas phase--there are no acids involved until refining, and even then, there is selective gas phase chemistry for the Pt, Pd, and Rh. It also isn't cheap to set up and has its inherent disadvantages (and advantages) with arc/plasma torch melting. It's a better mouse trap in certain circumstances (that is to say, it works). 

As far as aqueous leaching is concerned; it's a matter of price point.


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## bubba (Apr 11, 2011)

Lou said:


> bubba said:
> 
> 
> > Sure. Everyone I meet knows more about this business than I do. Even the guy with a pickup truck that brings me 10 converters at time. I am used to it. And I never said it take 90 days to do an assay, we assay in house everything before it leaves our dock.
> ...



No apologies needed friend, there are many very specialized facets to this whole precious metals business, I enjoy reading about the gold, silver side, very interesting. We all have something to contribute, I wish I would have found this forum sooner. 
You are correct that leaching is a matter of price point, I am trying to convey that nobody, at least no one of any size, leaches cats. It is just not cost effective. I am a moderate sized operator, but I have friends that cut over 100,000 units a month, all very smart people. When you are talking about a 50kw arc furnace, it has something like a 20 ton per hour capacity. At 3100 degrees, very little flux is required, and the material is so rich, it does not need much of a collector. What this breaks down to, is that is is really hard to compete with a smelter, many, many have tried including myself.


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## qst42know (Apr 11, 2011)

bubba

Do you refine your assay gold to reuse?


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## Barren Realms 007 (Apr 11, 2011)

Very interesting thread. But bubba one thing amazes me is that you are settling for only 90% on your metals if memory serves me. I would think you could do better?


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## skippy (Apr 11, 2011)

Nitpick: It's going to take a heck of a lot more than 50kw to take 20 tons of ceramic to 1500C and liquify it in one hour.


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## bubba (Apr 11, 2011)

skippy said:


> Nitpick: It's going to take a heck of a lot more than 50kw to take 20 tons of ceramic to 1500C and liquify it in one hour.



Your right. make that 50 MVA .a typo on my part. and I believe it is D.C. 
Only seen one run once, cooling water pouring over the top, and all of that electricity, damn scary.


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## bubba (Apr 11, 2011)

qst42know said:


> bubba
> 
> Do you refine your assay gold to reuse?



No, I am in california, to many issues


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## bubba (Apr 11, 2011)

Barren Realms 007 said:


> Very interesting thread. But bubba one thing amazes me is that you are settling for only 90% on your metals if memory serves me. I would think you could do better?




Well I am not selling metals. Even our baghouse dust, which is the richest material we produce is only 3000ppm Pt. 1500ppm Pl. and 500ppm Rh.
So, as you can see there is considerable over burden.


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## Barren Realms 007 (Apr 11, 2011)

bubba said:


> Barren Realms 007 said:
> 
> 
> > Very interesting thread. But bubba one thing amazes me is that you are settling for only 90% on your metals if memory serves me. I would think you could do better?
> ...



Ok that makes sense then.


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## skippy (Apr 14, 2011)

Ok, back to my observations. I bought a couple of stainless substrate cats, with the intention of seeing how easy it would be to get the foil out. I haven't really tried anything with them yet, but I just thought I'd say that the stuff is really fricking tough $%#@. I can't see any easy physical way of doing it sans a super heavy duty hammer mill.


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## bubba (Apr 16, 2011)

skippy said:


> Ok, back to my observations. I bought a couple of stainless substrate cats, with the intention of seeing how easy it would be to get the foil out. I haven't really tried anything with them yet, but I just thought I'd say that the stuff is really fricking tough $%#@. I can't see any easy physical way of doing it sans a super heavy duty hammer mill.



You know skippy, for years we were throwing stainless foil cats into the scrap because there was no processors , now there are several. you are correct about the hammer mill.
First they de-can with a plasma cutter, then dip the foil in liquid nitrogen to make brittle, and then run the substrate through a series of progressively finer grind mills. if the grind is fine enough, the washcoat can be seperated in an air classifier.


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## skippy (Apr 24, 2011)

Bubba so ok, now I just need one of those big LN2 tanks you see outside of research buildings, gas co etc. :lol: Or hope for a really cold winter.


I thought I would add a little note to something discussed earlier in this thread. I had dissolved enough platinum
from a sample overnight in straight HCl that I got a nice orange stannous test. I wondered how the HCl was able to do it.
My current belief is that the HCl dissolves some cerium (iv) oxide from the washcoat, which then reacts with the HCl to form 
cerium (iii) chloride and Cl2.


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## qst42know (Apr 24, 2011)

Part of the purpose of a cat is to break down NOx. I noticed a recently de-canned cat to shed some material when left out in the rain one time. Perhaps it held some residual nitrate compound and reacted accordingly?


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## skippy (Apr 24, 2011)

Most cats do have ceria in them. I know for a fact that after roasting a cat with sulfuric acid I got a good amount of chlorine (or maybe chlorine dioxide?)
coming off after adding HCl to the leach solution. A bit of an unpleasant surprise actually when it happened.
When the ceria dissolves it becomes a potential oxidizer as it's in the cerium (iv) state and can oxidize HCl, whereupon the cerium is reduced to cerium (iii).

I don't know why your cat lost material like that - I bet it was a physical rather than chemical thing, still interesting though. The washcoat can come off separately, in fact I read a 
paper where some fellows took some catalyst and put it through an attrition grinder (think that's what it's called) and due to the washcoat being more friable were able to get a large majority of the PGMs into a much smaller fraction of ceramic than they started with. Maybe a freeze thaw cycle or two would help loosen the washcoat too.


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## bubba (Apr 24, 2011)

skippy said:


> Most cats do have ceria in them. I know for a fact that after roasting a cat with sulfuric acid I got a good amount of chlorine (or maybe chlorine dioxide?)
> coming off after adding HCl to the leach solution. A bit of an unpleasant surprise actually when it happened.
> When the ceria dissolves it becomes a potential oxidizer as it's in the cerium (iv) state and can oxidize HCl, whereupon the cerium is reduced to cerium (iii).
> 
> ...



You are talking about two different animals. Foil cats and ceramic cats. 
Yes the ceramic cats have cerium and zirconium. High quality cats like the ones made in europe have higher amounts of these elements to provide better structural strength. Lower quality cats, like aftermarkets and chrysler's, have lower amounts of these materials. That's why a guy like me see's more of the cheap ones, because they crack, break, wear and turn sideways and stop working. 
As far as the washcoat coming off, well, it seperates easily from the foil cats, but not the ceramic. We have tried many grinds,from 100 mesh, all the way down to 20-50 microns, and tried to do gravity/fractional seperation. no dice.
The ceramic biscuits are made by dipping the biscuit into a PGM solution, so the metals absorb into the surface of the ceramic, and they don't come off easily.


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## skippy (Apr 24, 2011)

Bubba, yes I was talking about ceria in a ceramic cat, to explain observations I made back at the very start of this thread. 

The ceria and zirconia is primarily not for physical strength. It keeps the alumina wash coat from sintering at high temps, although I guess you could call high temp stability a form of strength.
The ceria also physically holds onto oxygen and releases it when the engine is running too rich, helping keep the oxygen/hydrocarbon ratio in balance inside the cat. It's pretty important in two biscuit cats.

In the paper I read they were using an attrition scrubber. http://www.westpromachinery.com/p_attrition_scrubbers.htm It's a rather different action from other kinds of grinding which may explain their claimed results. The attrition scrubber basically propels two streams of the material at each other and the result is a scrubbing sort of wearing of the material. IIRC they were able to get 75% or 85% of the PG metals in 15% to 25% of the original weight. Useful? Probably not, but I found the principle interesting. The wash can separate somewhat from the cordierite, and this can be observed with the naked eye upon crushing, but of course it is likely near impossible to do completely and cleanly. 

Did you try any other ways besides the different leaching formulas, and the physical separation through crushing idea, Bubba? You put a lot of effort into trying to find a way to do it in house for sure!


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## bubba (Apr 25, 2011)

skippy said:


> Bubba, yes I was talking about ceria in a ceramic cat, to explain observations I made back at the very start of this thread.
> 
> The ceria and zirconia is primarily not for physical strength. It keeps the alumina wash coat from sintering at high temps, although I guess you could call high temp stability a form of strength.
> The ceria also physically holds onto oxygen and releases it when the engine is running too rich, helping keep the oxygen/hydrocarbon ratio in balance inside the cat. It's pretty important in two biscuit cats.
> ...



We have not done much in the last 10 years as far as trying to do anymore separations. It was a long, expensive journey to get to a place where we stopped looking at specific trees, and start seeing the whole forest.
I do not want to over complicate this whole idea, as far as ores go, ceramic catalyst is a very simple ore. If you are going to leach, there is not a great deal of pre-treatment required, other than some carbon to deal with. No leach that I have seen will get past the carbon, we built a rotary roaster that got 1200 degrees. It did a pretty good job on the carbon. 
So compared to some tough complex ores that are bound in sulfides, tellurides, etc. converters are a straight forward process. 
I can't even begin to remember all of the formulations we tried, I have a limited mining background, so I knew enough to know when I needed to call in help. I had a top notch extractive metallurgist work with us, he would bill out at $1000 a day, plus expenses. that added up quick. 
The tests I can remember were AR, hot AR, hot cyanide, SSN, hot SSN, thiourea, sulfuric at 400 degrees (no kidding), and more than a few that I have forgotten.
It's interesting, it's fun to talk about.........but it's not a money maker.


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## Barren Realms 007 (Apr 25, 2011)

bubba said:


> skippy said:
> 
> 
> > Bubba, yes I was talking about ceria in a ceramic cat, to explain observations I made back at the very start of this thread.
> ...



Did you by any chance try thiosulphate?


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## bubba (Apr 25, 2011)

Barren Realms 007 said:


> Did you by any chance try thiosulphate?


 No, never did.
Had no good success when we would deviate from a nitric-based solution, the most cost effective being SSN.


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## HAuCl4 (Apr 27, 2011)

skippy said:


> Bubba so ok, now I just need one of those big LN2 tanks you see outside of research buildings, gas co etc. :lol: Or hope for a really cold winter.
> 
> 
> I thought I would add a little note to something discussed earlier in this thread. I had dissolved enough platinum
> ...



Contrary to what you have likely read, HCl alone will dissolve palladium oxide SLOWLY, whilst aqua regia will not!. That's why you must apply HCl first!. 8)


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## Lou (Apr 27, 2011)

Contrary to what you've said, whether or not HCl dissolves PdO is contingent on how hot the PdO was beforehand. If it's heated to just before it would normally decompose, it's pretty well insoluble and can best be called dead burnt.


HBr and HI work better than HCl.


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## HAuCl4 (Apr 27, 2011)

I used to get touchy too!. Till I learned that there is nothing new under the sun. :lol:


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## Lou (Apr 27, 2011)

Oh, I wasn't being touchy! Just reminding you that there are exceptions to every rule, and exceptions to the exceptions.


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## Oz (Apr 28, 2011)

Oh come on Lou, I saw it in print. Honest I did!

Kidding aside, I have run into circumstances in chemistry that no matter the fine pedigree of the information, it just isn’t always true.


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## HAuCl4 (Apr 28, 2011)

Hi bubba. Thanks for your posts. Tough biz it seems. 

As in other PMs business, it seems controlling the volume is the only way to profit. Glad you found your niche. 8)


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## skippy (Aug 20, 2011)

I would like to share a little tip for decanning cats. In lazersteves video he makes a series of cuts with a hand held abraisive cutoff disc in an angle grinder which allows you to open the cat kind of like a book. Steve's way is very clean and methodical, but maybe a little slow I learned a pretty quick way to decan with one cut, although it doesn't leave the comb whole.

If it is a larger cat with two biscuits, cut it in the middle between the two biscuits, or if a smaller cat just cut an end off close enough to the biscuit so that you have a nice big opening. Then take a hammer drill and a large masonry drill bit and drill a half dozen holes in the biscuit. Be careful though, as the bit can catch wire wrapping or seams of the cat and start spinning the cat out of control :shock: you might want to use a vise. Once you have the holes in the cat take a big hammer and smash the the ceramic out. The holes weaken the biscuit so that it smashes out easily. It's a pretty quick and easy process, especially if you make your cut with a chop saw. I got the idea of using the hammer drill off a post on the metal finishing forum. The fellow there didn't chop the cat, but just went at it through the pipe with the hammer drill and then rammed it through with a big piece of round steel stock. I think my modification works quicker and with less dust.


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