# new ideas for cats



## arthur kierski (May 29, 2008)

preamble:Hokes in her book says that by leaving for a time pdo in pure hcl ,it desoxidises and it becomes easy for chemical attack----by analogy ,the same happens to rho(not rh2o3 which dissolves easily)---in cats you have a similar situation: you have together pd, pdo,pt,rho,rh2o3,rh---if you leach the substrate by any way,the only metals tha goes to solution is rh2o3 and rh and pt and pd(pdo+ rho stays in the substrate)----so i think the solution is: take a powdered substrate and leaves for a time covered with hcl(no water) ----them add h2o2(100 volumes -30%)-------at room temperature ----at a few minutes a strong reaction will take place and the pt,pd and rh will go to solution--- them to reforce the situation add clorox(12%%conc) twice---every half hour-----i think this will extract all the pgm from the cats--if not, repeat the procees since it is very easy and does not require heat--
i am going to do this today --and then i will pass the results(if it works)
please replyes and ideas --thanks arthur


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## loco (May 31, 2008)

interested in how this turns out. I wish I had 1/2 the chemistry knowledge floating around this site that some of your have. will be looking forward to how this fairs.


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## arthur kierski (May 31, 2008)

loco, it gave 1,48grams of pgm which i did not separate from each other yet. aniway it was less that i expected and will monday do a second leach-----i am doing a second leach because the solution obtained(with 1,48grams) was beatifully pinkysh red and up to now ,the solutions that i got was always yellow---------------------------------------------------------------in parallel i made the same experiment with 5,1 grams of rhodium powder and only 0,2grams went to solution---meaning to me that rh does not dissolve with this idea
thanks for the reply---will mantain you informed


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## Irons (May 31, 2008)

arthur kierski said:


> loco, it gave 1,48grams of pgm which i did not separate from each other yet. aniway it was less that i expected and will monday do a second leach-----i am doing a second leach because the solution obtained(with 1,48grams) was beatifully pinkysh red and up to now ,the solutions that i got was always yellow---------------------------------------------------------------in parallel i made the same experiment with 5,1 grams of rhodium powder and only 0,2grams went to solution---meaning to me that rh does not dissolve with this idea
> thanks for the reply---will mantain you informed



It just takes longer. If you continue the reaction long enough (months), most of it will probably go into solution.


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## arthur kierski (May 31, 2008)

iron,if is a question of time(velocity of the reaction),surely there might be away to quicken the process????
thanks for the reply


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## Oz (May 31, 2008)

If I’m not mistaken lasersteve did something very similar as a test on 1 cat but skipped the H2O2 basically his HCl Cl with heat. Might be worth asking him to look at this thread for comment.

The approach the 2 of you are taking is very interesting especially since you both have access to PGMs as controls.


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## arthur kierski (May 31, 2008)

oz ,i did my experiment after i read about steve experience with hcl-clorox-----as i always dissolved pt with Ap and steve dissolved gold foils hcl-clorox and pd dissolves either by any of the 2 ways, the problem became(to me) the rhodium ---i do not know how much rh is in the 1,48grams of pgm obtained--will know more monday---but became a bit pessimistic because my paralel experience with 5,1grams of rh powder
i think it might work (i did not use heat as steve did because if the experiment works without heat,i will be able to extract pgm from many kilos of cats daily-)
what preocupied me was what iron said:everything will come out , but it will take a long time----it will work if i can hasten the process----all the process took me only 5hours on friday


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## Oz (Jun 1, 2008)

Arthur,

Reading between the lines a bit on your post are you saying in the past you went after the Pt first with AP, then after AP went after the Pd with HCl-Cl, leaving you only Rh as a problem? Also at the beginning of this thread if I understand you correctly it seems you are trying to oxidize the PGMs before the addition of Cl. But you also state “if you leach the substrate by any way,the only metals tha goes to solution is rh2o3 and rh and pt and pd(pdo+ rho stays in the substrate)”. I’m assuming pdo + rho are oxidized Pd + Rh, if so how are you bringing them into solution given your statements? I’m no chemist but if you could clarify it would help me understand your thought process.

I just started trying the HCl-Cl on foils. After asking Steve about using it on karat gold that was inquarted and taken from a nitric solution I tried sponge as well. The only problem I have had so far was getting full dropping of the gold with SMB using a weight of SMB equal to expected yield. I then went to twice the amount of SMB than I should have needed as I have heard excess nitric from AR can cause you to need additional SMB as well as excess chlorine and I had the potential for both from the nitric and HCl-Cl. 

Since the second dosing with SMB did not give me full extraction I boiled the solution for a half hour thinking I would eliminate any chlorine or nitric from the solution. There was still no additional dropping even after cooling. I was ready to boil it dry and incinerate to start from scratch but on a whim thought to try dilution. After doubling the solution with water I got immediate additional dropping and the solution was clear and settled within 10 minutes. A quick stannous test confirmed a complete reaction.

I’m not sure what was causing my problem but I obviously had too great of a concentration of something for the exchange. That last batch of sponge soaked in plenty of water for 3 days and was stirred a couple times a day and the water was clear so I thought it well washed of nitric and Cu before the HCl-Cl. The batch I am working on now I boiled the sponge in 3 changes of water and was amazed by how blue the water was getting from nitrated copper once boiled. I’ll see how it goes this time after the boiling changes of water. I will also give it a boil in the HCl as well before adding Cl to see if it needs further washing. I don’t plan on ammonia washing until I have my first precipitation unless it proves necessary.

Now I know that you are working with different PMs but I thought it might be worth mentioning my early results with an Au, Ag, Cu, alloy with HCl-Cl in case you find a similar parallel in working out your method with PGMs.

If you care to PM me on any of this you are more than welcome to. I have PGMs just sitting waiting for me to decide how I want to proceed with them. You don’t say what changes on Monday for you with your testing, but I am anxious to hear more. 


Oz


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## Oz (Jun 1, 2008)

I wish to clarify a potential misunderstanding. 

I have had a forum member that will remain anonymous politely tell me that my 2 prior posts here may have been a distraction that would possibly prevent him from learning what was being explained. It was further implied that my post had come across as though I was presuming to teach something to Irons and Arthur. I so hope that that was not how they took it. You are both way beyond my knowledge and I am grateful of that fact. Which is why I ask questions, I had thought I was clear that I had PGMs that I was unsure how to process. 

So my apologies to all if I have caused a problem, it was not my intent. If either of you feel that I am a distraction on this thread I will politely just read and not comment.

Oz


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## arthur kierski (Jun 1, 2008)

oz,no distraction at all--i asked for information and replyes and you are welcome because on your reply (carat gold) you gave me a clue that my 5grams parallel experiment was uselees and my hopes of having rh in the 1,48grams obtained, raised a lot---the parallel experiment should be done with 0,5grams of rh and not with 5grams----i was comparing 2 diferent things because 1kilo of substrate does not have more then 0,5grams----now your questioning---there are many tipes of oxides of rh and pd,the main ones are rh2o3 and rho ,and pdo and pdoxide something
(pdo2 or pdo3)---pdo and rho when formed becames very dificult to chemical attack(leach) so one have to modify this oxides before leaching--the normal way to desoxidize this oxides is using (boiling) a solution of sodium formate with na2co3 at ph1o----reading hokes book she says that one can desoxidise pdo and by analogy(mine)rho simply resting these oxides in a pure hcl solution---that was what i did---as i told you i obtained from the process a beautifull pinkish red solution which strongly indicates pdcl and rh2cl3---platinum solution is yellow and the collour of the solution prevails purplish red. i think that i am finally on the way and 
what is scaring me a bit is irons remarks on the time to extract all the pgm---think of a way to hasten the process and probably we will susceed


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## lazersteve (Jun 1, 2008)

Arthur,

Rhodium will dissolve if fused in an oven with potassium disulfate (K2S2O7) and sodium chloride (NaCl) for 1-2 hours at 500-550C in a Pyrex beaker or porcelain dish covered with a watch glass. Extreme care must be taken to handle the SO3 off gases. See Lou's post below!!!:wink:

This method will dissolve a maximum of 80% of the Rh metal. The ratio of the reactants is 6.8 g NaCl + 14.8 g K2S2O7 per gram of fine Rh powder. Mix and grind all ingredients together to a fine powder. 

After the reaction cools dissolve the red solid in 80 mL H2O + 20 mL conc HCl. Approximately 20% of the metal will remain undissolved and can be filtered off (approximately 0.2 g Rh per gram reacted) and added to the next batch.

Alternately you can dissolve Pt/Rh alloy with boiling AR directly if the *Pt* content is greater than 90%. 

Yet another means of directly dissolving Rh completely involves melting 1 part Rh + 4 parts Pt + 1 part Cu. Cornflake or shot the resulting alloy in cold water then treat with AR.

To bring solid Rh into a finely divided state you can fuse with 10 parts Zn under a layer of ammonium chloride to prevent oxidation of the zinc and dissolve the resulting alloy with 6M HCl. Filter out the fine Rh powder and clean with boiling dilute AR. The Rh powder remains undissolved.

I hope all the available options doesn't confuse you more than it helps. I've been researching several means to attack Rhodium and have found many possible methods. I plan on getting around to demonstrating them all on video in the upcoming year. 

I also plan on attempting the sodium peroxide fusion of the honeycomb substrate to recover the PGMs with out direct acid treatment of the honeycomb. I'll provide details as I uncover them. Including the production of the required sodium peroxide.

Edits in red.

Steve


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## Oz (Jun 1, 2008)

I am glad it was not an unwelcome interruption to you, and I hope Irons feels the same way. 

Your reply does indeed help me understand what you are doing better. I am glad that in a small way my ramble managed to help. There is a little humor in the fact that you think your control experiments problem is too much Rh. There are a few that would like that problem.

I will think on what you wrote before I reply further, and I will get back to you on your PM as well. But for now it is a glorious day and I am off to a clam bake for some good food and a few beers.

Thanks again!

Oz


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## Irons (Jun 1, 2008)

arthur kierski said:


> iron,if is a question of time(velocity of the reaction),surely there might be away to quicken the process????
> thanks for the reply



Increase temperature, pressure and concentration of reactants. The problem is the cost of the equipment needed to do it safely that won't be destroyed in the process.

Speed costs money.

When doing a bisulfate fusion you should heat it until the white fumes come off, indicating that SO3 is being produced. This is what reacts with the Rh. If you heat it to too high a temperature, it will drive the SO3 off and the reaction will cease.

SO3 is very corrosive and a safety hazard, proceed accordingly. A charcoal fire outdoors might be a less expensive substitute as the fumes will corrode a furnace rather quickly.


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## arthur kierski (Jun 1, 2008)

thanks steve for the various informations for getting rh from powders--some i already (not with cats)use---i have sodium bisulfate in stock(100lbs always) because it is a big tool for my rh extraction from various types of scraps and as i extract 100grams of rh monthly i cannot survive without it-hope that your information (the ones that you are preparing for next year)arrives sooner---it is very important to me and i think to many others forum members---------------------------------------
iron ,if the process i am using requires heat but extracts a great percentage,iwill do it ---but pressure and equipment if required , them i shall continue with my methods of extracting pgm from cats
thanks again to all


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## Lou (Jun 1, 2008)

Rh chlorinates quite nicely to Na3RhCl6 at 600-700*C in the presence of either NaCl or KCl and is easily reducible. Assuming even a mixed bag of Pt, Rh, and Pd an effective separation can be made if one is willing to do the work.


Another option that many seem to forget is just how _quickly _ one can put intractable things like Pt and Pt/Rh into solution using AC electrolysis in simple HCl giving you [PtCl4]-2 and RhCl3 (complexes less easily!). 



What Irons said is right (in a sense) about the Rh reacting with the SO3. Many of you have probably noticed that Rh is unaffected by even concentrated sulfuric acid at room temperature. Take that same rhodium sponge and heat it with 98% H2SO4 to a very high temperature, to the point where you see white whispy fumes of SO3/H2SO4 and you will see the colour go from clear/yellow to a deep red-brown. 

Steve's fusion suggestion is similar to using alkali bisulfate. He uses potassium disulfate, which we should rather call potassium pyrosulfate with table salt. Still, in his reaction, it is the pyrosulfate that does the oxidation. 

from K/NaHSO4:

2NaHSO4 -> Na2S2O7 + H2O @200C all the way to 600C


Na2S2O7 -> Na2SO4 + SO3 starting at 270C and finishing just below 800C.
So obviously there is overlap in the reaction, but it is the pyrosulfate that is actually doing the work. Since both persulfate and bisulfate both lead to pyrosulfate, it is better to use sodium bisulfate as it is cheap.

Persulfate (used as an etchant works just as well, just more expensive):

This is what is happening (from K persulfate):
2 K2S2O8 ---> 2 K2S2O7 + O2

K2S2O7 ---(H2SO4)---> K2SO4 + SO3 
(at lower temp as I recall). 

*A note on the SO3, I don't think care would help much if one dared this in one's garage or house. Do this outside on a windy day or in a fume hood with an excellent draught--sulfur trioxide is very  aggressive!*

Another note, the co-dissolution of Pt/Rh where Pt is > 90% by mass does work, but believe me Steve, you do not want to do it unless you have a powdered alloy or its in the form of thin wire or foil. Otherwise, I can promise you that it will take many hours; a long time ago, I tried dissolving Pt/Rh shot in boiling AR and it took a ridiculous length of time. Days I think. If you have a rolling mill or even an anvil, for any Pt/Rh or Pt/Ir (<-- especially! these are hell to dissolve), use it! Flattening will be slow going with both of them, particularly the harder Pt/Ir alloy.



And now more on topic stuff:
Arthur, when you tried the HCl/NaOCl method with pure rhodium, you said you saw only 200 mg dissolve? Did you run it at high temperature? Either that 200mg was platinum (which will dissolve) or it was not heated long enough or hot enough to get more Rh into solution. What colour was the solution? Brown or yellow?

Lou


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## arthur kierski (Jun 1, 2008)

lou,i did the 5,1 grams of rhodium with hcl+h2o2 and then more hcl+naocl at room temperature because i was doing a comparisson,the collour of the solution became yellow


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## markqf1 (Jun 2, 2008)

Fusion, fusion, fusion.
Time and chemicals.
If it were only so easy.  
Some of you guys here should be building rocketships,... if your not already. :idea: 


Mark


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## Irons (Jun 2, 2008)

markqf1 said:


> Fusion, fusion, fusion.
> Time and chemicals.
> If it were only so easy.
> Some of you guys here should be building rocketships,... if your not already. :idea:
> ...



I wait for the Asteroid to come to me. Wait, that's not such a good idea. :twisted:


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