# Taming the BIG Cats



## qst42know (Mar 14, 2009)

I'm open to suggestions on this one. This was a highway drop my brother found. Strangely the scrap yard offered him a whole $8.00 for it thankfully he declined. The biscuit weighs a whopping 8 pounds though it may be a tiny bit damp. It's way larger than any glass ware I own and stands above the crock pot I might have tried. I may need to break this one up. That's a gallon of paint for scale. 7 inches tall and 7.5 in diameter.

Anyone ever run these big deisel cats?


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## lazersteve (Mar 15, 2009)

Qst,

I have processed two that a member sent me as a test.

As a side note I was unable to get back in touch with the member so if you are reading please PM me.

I used a 3.5 gallon bucket and HCl-Cl to successfully harvest the PGMs from the unit. When I received it the honeycomb was already split down the middle, but it would have fit in the bucket whole. 

The first honeycomb yielded just shy of 6 grams of Pd and no Pt or Rh. The second one (more of an off white colored ceramic) produced no yields. Both were extracted as per my Pt DVD.

The units were *loaded* with carbon.

Steve


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## qst42know (Mar 15, 2009)

Steve do you recall an odd stannous test on these?

Some scrapings in a test tube with hot HCL/CL yields a dark green solution but a grey/black swab.

And yes, it's like a big pepper shaker. tip it one way and carbon pours out and back the other way and more carbon pours out.

Left swab after stannous, right swab no stannous.


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## Lou (Mar 15, 2009)

If you go to process these, you'll see that they are loaded with soot. Burning off the soot to help increase access to the metal and reduce any carbides to metallic palladium will soon leave you with a difficult situation.

Palladium oxidizes at around the same temperature that the carbon and carbides are oxidizing/combusting at, so you will have PdO formed. Palladium (II) oxide is only very passably soluble in HCl-H2O2 and not much more so in aqua regia. It needs to be reduced. This can be done with basic (c. 10-11 pH) ammonium or sodium formate solution at ~80 Celsius. The formate salts are easily made in situ.

I wouldn't think these are worth it unless you have a few of them.


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## qst42know (Mar 15, 2009)

What would happen to the carbon if I used a technique that to me somewhat resembles Wet Ashing. It would not be difficult to split this cat into two disks that would then fit in a crock pot.

It's a sulfuric acid sodium chloride leach described in this brief article.

http://findarticles.com/p/articles/mi_qa5348/is_200304/ai_n21328741

What would become of the carbon?

In what form would the palladium be collected?


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## Oz (Mar 15, 2009)

Lou,

Would not all the Pd that was going to oxidize have already formed PdO from the temperature of the exhaust gasses while installed on the truck, or do these big diesels actually run that cool?


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## Platdigger (Mar 15, 2009)

qst42know, I printed that entire article out a few years back. If you sudy it carefully you will see that one: the catalyst material they experimented on was used in making nitric acid.
And two: that if they washed the nitrates, or nitrous oxide out of the material........that then, this method almost completely failed to work.

So, what I am saying is, for this to work good, you will still need an oxidizer.
Randy


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## Lou (Mar 16, 2009)

Oz,

The fact that there is carbon deposited onto the converter indicates a strongly reducing environment. You will not have free carbon (read soot) in an oxygen rich system.


Lou


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## Platdigger (Mar 16, 2009)

So Lou, 
do you think this could have been why the second honey comb
that Steve tried to extract from yeilded nothing? (the pd was oxidized)?

Steve said: "(more of an off white colored ceramic)"


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## qst42know (Mar 16, 2009)

Platdigger said:


> qst42know, I printed that entire article out a few years back. If you sudy it carefully you will see that one: the catalyst material they experimented on was used in making nitric acid.
> And two: that if they washed the nitrates, or nitrous oxide out of the material........that then, this method almost completely failed to work.
> 
> So, what I am saying is, for this to work good, you will still need an oxidizer.
> Randy



Now that you mention it I do recall the full article you posted. While avoiding adding AR they ended up creating it unintentionally from the residues. 

Sorry for my poor memory.


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## patnor1011 (Mar 16, 2009)

my vw vento just broke down. something with clutch its not worth repair so I decided to scrap that old buddy. so finally I will have cat to play with :wink:


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## Irons (Mar 16, 2009)

Lou said:


> If you go to process these, you'll see that they are loaded with soot. Burning off the soot to help increase access to the metal and reduce any carbides to metallic palladium will soon leave you with a difficult situation.
> 
> Palladium oxidizes at around the same temperature that the carbon and carbides are oxidizing/combusting at, so you will have PdO formed. Palladium (II) oxide is only very passably soluble in HCl-H2O2 and not much more so in aqua regia. It needs to be reduced. This can be done with basic (c. 10-11 pH) ammonium or sodium formate solution at ~80 Celsius. The formate salts are easily made in situ.
> 
> I wouldn't think these are worth it unless you have a few of them.



Try staight HCl. Warm, concentrated HCl will dissolve PdO. It's a good way of getting rid of Pd contamination without attacking Gold or Pt.


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## Lou (Mar 16, 2009)

It still takes a long, long time. Too long for my liking.

Concentrated hydrobromic acid works much faster, but most people don't have access to that.


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## Irons (Mar 16, 2009)

Lou said:


> It still takes a long, long time. Too long for my liking.
> 
> Concentrated hydrobromic acid works much faster, but most people don't have access to that.



It is a slow process. With finely divided material, it's not too bad.

I have all the time in the World. I do it because it is my pleasure.


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## Harold_V (Mar 17, 2009)

Irons said:


> I have all the time in the World. I do it because it is my pleasure.


That's one of the things that has been slow to sink in for me. My refining service demanded such a short turn-around that I wasn't afforded the luxury of allowing things to work at their own pace. 

I have been endlessly impressed by our own Lazersteve in his ability to put items in a solution that may take weeks to process, and to simply go on with his life, attending to them as time allows. What a wonderful attribute to have, and to be able to exercise! 

Stay the course, Irons! 

It's a different world for the likes of Lou, who relies on rapid processing to remain competitive. 

Harold


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## Irons (Mar 17, 2009)

Harold_V said:


> Irons said:
> 
> 
> > I have all the time in the World. I do it because it is my pleasure.
> ...


Thanks Harold. You make a good point about time being money.
Recovering the Bromine is also a costly and time consuming part of the process, while Chlorides are not worth the trouble.
Being in a hurry can get one in trouble. If the material being processed contains any of the Selenium group (Se,As,Ge), using HBr renders them extremely volatile. It's a standard process for removing those elements, but is very hazardous unless done under very controlled conditions. Cats are not a problem but electronic scrap and many ores contains a substantial amount of Arsenic.
Using HCl is a standard technique. Igniting gold precipitate and using HCl to remove Pd is a part of Lasersteve's CPU Gold recovery technique.

Those not familiar with chemistry need to understand that a given process may not work or be hazardous under other circumstances or with a different feed stock.

Chemical Engineers make a good living by understanding these pitfalls.


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## Harold_V (Mar 17, 2009)

Irons said:


> Those not familiar with chemistry need to understand that a given process may not work or be hazardous under other circumstances or with a different feed stock.


Indeed! That was one thing that came to me with my first attempt at using cyanide for processing a complex gold ore. The contained gold was almost impervious to the cyanide, dissolving a very small percentage as applied. The addition of a trace of bromine to the process made an immediate improvement and resulted in resounding success. 

It's obvious that each ore type has its own problems, so knowing how to process one does not imply that you will be successful with others. I think we saw evidence of that when Lazersteve entered the contest to develop a process for one of the major producers of gold. Even with their considerable background, they obviously were having difficulty solving a given problem. 

It's a real pleasure to see you back on the board, Irons. I gather you are improving daily. 

Take care, and be well. 

Harold


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## qst42know (Mar 17, 2009)

Irons said:


> Those not familiar with chemistry need to understand that a given process may not work or be hazardous under other circumstances or with a different feed stock.
> 
> Chemical Engineers make a good living by understanding these pitfalls.



The scale of your reactions can also multiply hazards. 

Still curious if wet ashing would work I put a chip of this material in a test tube with a few ml of sulfuric and a couple of prills of sodium nitrate. When heated the solution first went all black, on continued heating the black disappeared and became a transparent golden brown. In only about 2 min. the chip of ceramic ended up clean and white, however the reaction even at this tiny scale was extremely violent foaming, spitting, and fuming. Though it seems to work fast at any larger scale than a few crumbs it would be downright deadly. 
Now I know :wink:


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