# My first cat extration.



## Joeforbes (Apr 30, 2011)

First, I apologize for not posting pictures. My camera keeps saying something about a lens error and I can't figure out what's wrong with it. Hopefully I'll be able to post some in the morning. 

I used a converter from a junked 1996 Cadillac Sedan DeVille that I had sitting around. After boiling in AR for about 6 hours, stannous testing showed only platinum in the solution. I filtered it several times to remove the particles, and after boiling it down to remove the HN03 I'm left with about 90ml of dark orange syrup. The stannous test turns so orange it looks dark red.

Now I'm ready to precipitate, but I have a couple questions - 

In lazersteves platinum and palladium refining dvd (which is one of my better investments, to anyone who might not have it yet) he dilutes his syrup with about three times its volume in water. Everything I've read so far indicates that the more concentrated the solution, the more effective the precipitation will be. Would it be recommended to dilute with as little water as possible? It seems that three times the volume would be more than needed to make the syrup fluid enough.

How much Ammonium Chloride should I add to a given amount of water to make a 15% solution to rinse the precipitant? 

I'm no chemist by any means, but I am doing my best to learn this process. I'd say it is going considerably better for my first time than I had expected, though. 

I know those questions seem pretty basic, but please bear with me!  I just want to be sure that I do things correctly.


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## Platdigger (Apr 30, 2011)

When Steve talks about diluting it would be before cementing with say zinc.
Not when going after the platinum chloride salt with ammonium chloride.
I would go with cementing this one. Then later you could combine the powders
from several cats and refine further if you choose to.
Besides the fact that the salts are some what hazardous to handle.


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## Harold_V (Apr 30, 2011)

Joeforbes said:


> and after boiling it down to remove the HN03
> <big snip>
> I just want to be sure that I do things correctly.


If you did as you said, boiling down, you didn't. One does not "boil down" values----they are _slowly evaporated_. Otherwise, values are lost in the vapors. They should never even be discussed in the light of "boiling down", because all too many take those words literally. 

Harold

Edit:
If you've read Hoke, it should be clear to you that if you intend to precipitate the platinum group of metals chemically, they do not respond well when they're dilute. If a solution is too dilute, it may fail to precipitate at all. Therefore, after you have evaporated your solution(s), use as little water as is required to put the values back in a solution that you feel will filter well. Remember, you'll have to wash down the filter after filtration, so there will be further dilution. Keep things as concentrated as you can when working with platinum and palladium..


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## samuel-a (Apr 30, 2011)

1 cat leach = 0.5-1.6g Pt, 0.3-1g Pd, <0.3g Rh (not necessarily all the three)

This is the range you should expect, with 90ml solution I'd say you are still too dilute to precipitate with ammonium chloride.
You should evaporate down to syrup consistency to properly dispose of free nitric, i doubt that 90ml have this consistency.

If you didn't properly eliminate the nitric, and have some Pd in solution, it will co-precipitate with the Pt to give brick red precipitate.

The "syrup" should be diluted just as far as achieving water consistency, it really doesn't take much, few ml... you can dilute with water or HCL...

I never bothered to check exact stoichiometry amounts and even if you do know the exact amounts, you don't really know how much metal is actually in stu. therefore, 1-2 grams of ammonium chloride is a good ballpark that seems to work for me per one cat.

Ammonium platinum chloride salt is practically insoluble in water with the presence of ammonium chloride, one mole solution will do the trick, 1mole = .53 gram ammonium chloride per 100ml of water...


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## Joeforbes (Apr 30, 2011)

Harold_V said:


> Joeforbes said:
> 
> 
> > and after boiling it down to remove the HN03
> ...




See, that's why I ask questions! haha. It's been quite a learning experience. I did boil the solution, but only a light boil. I guess I'll consider the values lost as the price tag for the lesson. Thank you for the reply!




Platdigger said:


> When Steve talks about diluting it would be before cementing with say zinc.
> Not when going after the platinum chloride salt with ammonium chloride.
> I would go with cementing this one. Then later you could combine the powders
> from several cats and refine further if you choose to.
> Besides the fact that the salts are some what hazardous to handle.



He condensed his syrup down to a little under 100ML, and diluted with water back up to just over 300 ML before adding the NH4Cl to precipitate the platinum. 



samuel-a said:


> 1 cat leach = 0.5-1.6g Pt, 0.3-1g Pd, <0.3g Rh (not necessarily all the three)
> 
> This is the range you should expect, with 90ml solution I'd say you are still too dilute to precipitate with ammonium chloride.
> You should evaporate down to syrup consistency to properly dispose of free nitric, i doubt that 90ml have this consistency.
> ...



I'll try to condense down the solution more, but it is already pretty thick. It's a combined solution of three total boils of the cat material, filtered and condensed. It only tests positive for Pt with stannous.


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## Joeforbes (Apr 30, 2011)

I condensed the syrup down to about 75ml and a good amount of crystals started forming. I dissolved them with a small amount of HCL, and added a little water to make the syrup more fluid, then I dropped in a solution of 5g NH4Cl dissolved into 20ml of water. The result was an orange powder that precipitated almost immediately. 

I took a small amount of the powder onto a q-tip, and dropped water onto it until it dissolved clear. I add a drop of stannous and got an immediate dark orange reaction. The result is the right q-tip in the picture. The left q-tip is a stannous test of the solution after filtering. The orange powder on the filter is the platinum salt of course.


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## samuel-a (Apr 30, 2011)

Congrats, The color of the salt is exactly the way it should be.

The reason that at 75ml you got crystallization is, in my humble opinion that you had too much metal cations, though i can't see the source.
The solution obliviously still holds significant amount of Pt in it that didn't drop duo to dilution.

when you swab hexachloroplatinate salt for testing, add to it a drop of HCL instead of water, it will better dissolve the salt to give more accurate reading.

You will be far better served cementing dilute PGM's solution with Zinc or Aluminum and re dissolving the black powders in a minimal amount of AR/AP for the reasons listed above. Dropping powders will save you a lot of time then evaporating large volumes of solution Plus, later PGM's drop will be much more efficient.


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## Joeforbes (May 1, 2011)

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