starting catalytic converter test with pics

[lazersteve]

The leach times will be slightly longer due to the lower population of the nitrate ions in the solution.

Steve

 

[pgm]

hi Steve..

well an update where i have got to.....i have filtered via a sharman plug but still the black powder was getting through so...i used a fine filter paper and then kept on filtering now the black liquid has changed to brown as i have kept on re-filtering and filtering time has gotten longer....i have 3 filters runing these are ashless filters...have pics

 

[pgm]

ok here are some more pics....always had something at the bottom....and the powder well here it is

 

[rusty]

From page 173 Hokes Refining Precious Metals Wastes.

While washing the powder into the filter paper, drop in
one or two crystals of sodium nitrate. (If washed with plain water,
this very fine powder will run through the paper; we add the sodium
nitrate and in some way it coagulates the fine powder and keeps it from
running through.

 

[lazersteve]

First off I would not try to filter out that much sediment. I would advise you allow the sediment all to settle overnight before even considering any filtration. Once the sediment has completely settled, siphon off the top layer of transparent liquid. This liquid should be sediment free and can be processed directly as usual.

Once you are down to the last of the liquid with the bulk of the powder in it, filter the large particles out using Whatman filter disc or several coffee filters. These will not get the fine stuff, but will get the larger particles out.

Now pack the neck of a plastic or glass funnel with enough sheets of Charmin tissue to allow 1-3 drops per second of flow through. Test with water first to get the flow rate to 1-3 drops per second, once the flow is right pour in the liquid that has been through a course filtration first to remove the bulk of the sediment. After a few hours the 100% sediment free liquid will be in the collection flask and can be treated as usual.

Steve

 

[rusty]

First off I would not try to filter out that much sediment. I would advise you allow the sediment all to settle overnight before even considering any filtration. Once the sediment has completely settled, siphon off the top layer of transparent liquid. This liquid should be sediment free and can be processed directly as usual..

Once you are down to the last of the liquid with the bulk of the powder in it, filter the large particles out using Whatman filter disc or several coffee filters. These will not get the fine stuff, but will get the larger particles out.

Now pack the neck of a plastic or glass funnel with enough sheets of Charmin tissue to allow 1-3 drops per second of flow through. Test with water first to get the flow rate to 1-3 drops per second, once the flow is right pour in the liquid that has been through a course filtration first to remove the bulk of the sediment. After a few hours the 100% sediment free liquid will be in the collection flask and can be treated as ususal.

Steve

So adding sodium nitrate to enhance clumping as quoted from Hoke's book not a good idea, thanks for setting me straight on this Steve a fellow just never knows how far the art of refining has progressed since she wrote the book. I'm pleased to be advised of the new procedure.

 

[lazersteve]

...
So adding sodium nitrate to enhance clumping as quoted from Hoke's book not a good idea, thanks for setting me straight on this Steve a fellow just never knows how far the art of refining has progressed since she wrote the book. I'm pleased to be advised of the new procedure.

Gill,

You mistook my post, I'm offering an alternative to your suggestion, not a replacement.

I have never tried the procedure you recommend, so I can not personally attest as to whether or not it works. I have utilized the method I posted many times and it works fine for me. I would suggest that the reader try both methods on a small scale and use the one that work best for them.

Steve

 

[pgm]

...
So adding sodium nitrate to enhance clumping as quoted from Hoke's book not a good idea, thanks for setting me straight on this Steve a fellow just never knows how far the art of refining has progressed since she wrote the book. I'm pleased to be advised of the new procedure.

Gill,

You mistook my post, I'm offering an alternative to your suggestion, not a replacement.

I have never tried the procedure you recommend, so I can not personally attest as to whether or not it works. I have utilized the method I posted many times and it works fine for me. I would suggest that the reader try both methods on a small scale and use the one that work best for them.

Steve

thanks just doing what you have said and it is working thankyou.....steve once i have the powder....what about any excess zinc....or should i not worry about this right now?.....or maybe i wash again with hcl only on the boil to clean the black powder...then filter again....

 

[pgm]

From page 173 Hokes Refining Precious Metals Wastes.

While washing the powder into the filter paper, drop in
one or two crystals of sodium nitrate. (If washed with plain water,
this very fine powder will run through the paper; we add the sodium
nitrate and in some way it coagulates the fine powder and keeps it from
running through.

How are you rusty....or shall i call you safty inspector...just joking....lol....thanks rusty....your a star

i will try adding sodium nitrate and do a test rusty......i will post what happens....i am doing a few leaches but learning and having plenty of fun at the same time

 

[Oz]

Just thinking out loud, if you add a little sodium nitrate to HCl you will be making a weak AR. So the addition of sodium nitrate may just give the allusion of speeding the settling process, when it is in fact just re-digesting your fine particulates instead.

When I do converters I typically cement with zinc, and yes you can get a very fine particulate. I do not beat myself up trying to filter it though. I let the solution settle overnight after cementation is complete and then decant it to get the bulk of PGMs, Then I let the decanted solution set for 3 days to a week before I carefully siphon the solution away from the small amount of very fine values that settled.

 

[rusty]

Just thinking out loud, if you add a little sodium nitrate to HCl you will be making a weak AR. So the addition of sodium nitrate may just give the allusion of speeding the settling process, when it is in fact just re-digesting your fine particulates instead..

We've been taught to test all solutions with Stannous Chloride to assure they're barren before discarding. The idea of adding a couple of sodium nitrate crystals is not mine but came directly from within the pages of Hokes Refining Precious Metals.

Ms. Hoke claims that this method worked, given her expertise I would think that she would have tested here solutions before tossing.

How about it Harold do you have a comment on this procedure, your self taught in the art of refining using only Hokes Book as a guide along with some experimentation as your knowledge and confidence built to level to permit this.

 

[Harold_V]

How about it Harold do you have a comment on this procedure, your self taught in the art of refining using only Hokes Book as a guide along with some experimentation as your knowledge and confidence built to level to permit this.

The only comment I have is more of a question. Why in hell would ANYONE want to wash the precipitated gold to a filter? There is no good reason to do so----and it just complicates the finishing process of washing the gold. Even if it's already washed, there's no better place to dry the gold than in the container in which it was washed. A gentle heat applied will dry the gold perfectly well, causing it to clump to the point where there are no fine particles about which to worry. If it doesn't, the gold isn't very clean.

When it comes to filtering, you have to know when to hold 'em, and know when to fold 'em. Anywhere in the process of washing, once gold is precipitated, is definitely not the time to do any filtering. The question is pointless.

Harold

 

[rusty]

How about it Harold do you have a comment on this procedure, your self taught in the art of refining using only Hokes Book as a guide along with some experimentation as your knowledge and confidence built to level to permit this.

The only comment I have is more of a question. Why in hell would ANYONE want to wash the precipitated gold to a filter? There is no good reason to do so----and it just complicates the finishing process of washing the gold. Even if it's already washed, there's no better place to dry the gold than in the container in which it was washed. A gentle heat applied will dry the gold perfectly well, causing it to clump to the point where there are no fine particles about which to worry. If it doesn't, the gold isn't very clean.

When it comes to filtering, you have to know when to hold 'em, and know when to fold 'em. Anywhere in the process of washing, once gold is precipitated, is definitely not the time to do any filtering. The question is pointless.

Harold

Ouch! Harold this discussion is about platinum - not gold. Ms Hoke says adding a couple of crystals of sodium nitrate helps in clumping the pt powders during the filtering precess. It all there on page 173 in black and white.

The only time I would consider using sodium nitrate with gold is during the smelting process.

 

[Oz]

Rusty,

Well you caused me to check Hoke to see a bit more of the context of her comments, never a bad thing.

Did you notice that on that same page where Hoke is addressing “stock pot concentrates” and you took your note from, she starts off by clearly stating “First wash the black powder with unusual care to get rid of every trace of hydrochloric acid. Wash until the washings have no effect upon blue litmus paper”. If I am not mistaken we are still discussing the removal of cemented values from AR that has had the nitric consumed by the addition of zinc. In essence a hydrochloric acid solution.

She clearly understood what I was pointing out, and yes, always test waste solutions. Pay attention as well that she is talking about filtering a nitric acid wash by adding sodium nitrate crystals.

While Harold may have misspoke saying gold, his advice is accurate. For me, settling and then decanting/siphoning is the way to go. With gold it takes little time to settle, but I have had PGM zinc precipitations take 5 days. That kind of fine precipitate is not something I wish to filter or have to separate from the filter later. The more you manipulate values from one container to the next, the more opportunity you have for losses.

The fact remains that if you add a soluble nitrate to HCl you are making a form of AR.

I am however sorry that it seems you felt I was criticizing you personally when it was obvious you were quoting someone else. I thought I was being rather casual in sharing my thoughts by saying “just thinking out loud”.

 

[Harold_V]

Sorry about my less than appropriate response. I was in a hurry and back tracked only enough to get a hint of a clue (obviously I wasn't successful!) I definitely should have gone beyond, so I would have had a better understanding of the question.

My apologies!

However, I tend to stand by my comments. Once you have values in a vessel, there is generally little need to filter unless you are shooting for precipitation. My policy was to leave values in the container and siphon or pour solutions, with the exception of solutions that were filtered in preparation for precipitation.

Any time you get a filter involved, you have the problem of material being trapped in the filter, plus the time it can take for filtration, which can be prolonged if the material being processed hasn't been treated well. It can be avoided by not filtering unless it's necessary. It often is not.

If the discussion is revolving around platinum group values recovered from solution with zinc, nothing changes. I good wash with HCl, then several rinses, followed by a drying, much the same as with gold, is all that is required. Filtration is a waste of time and serves no real purpose.

Harold

 

[Harold_V]

but I have had PGM zinc precipitations take 5 days.

Next time you have that experience, try boiling the solution with some added HCl. You may be pleasantly surprised that the solution clarifies and settle instantly. Excess zinc in solution tends to yield similar problems to aluminum in solution.

Harold

 

[Oz]

but I have had PGM zinc precipitations take 5 days.

Next time you have that experience, try boiling the solution with some added HCl. You may be pleasantly surprised that the solution clarifies and settle instantly. Excess zinc in solution tends to yield similar problems to aluminum in solution.

Harold

I have not processed converters for a while (I have a pile of them that need to be done though). I am a bit doubtful your solution will have much effect however as I do this hot and with excess HCl. Next time I do some I will try your suggestion just in case though.

When running converter material I usually use HCl and Cl2. Using chlorine I do not have the problem of nitric removal. Beyond the Pd, Pt, and Rh, there are other elements present that also go into solution. I use a stir plate when cementing with zinc as it is critical all solution comes into contact with the metallic zinc. Right near the endpoint of cementation you get a queer greenish hue to the solution. Then all at once, no matter how fine or how little the zinc additions are the solution goes black. It is the very end reaction that makes the finest particulate.

One of these days I should take my decanted solutions result of fine precipitate (not the main values, but only the finely divided and suspended values) and determine what percentage is PGM verses base metal cemented by the zinc. Purely speculating here, but I would think this last bit is Rh and base metal that gives the fine precipitate.

Have you done zinc cementation of just Rh perchance where you could describe the reaction? I am thinking that perhaps the difference is that any PGMs you would typically have been cementing with zinc may well have had the base metals removed prior. It may be also that there are base metals in converters that are not typically found in karat or dental scrap.

I would imagine Steve has seen what I am discussing. Perhaps he has tested the fine particulates from converter cementation further than I have.

 

[pgm]

Sorry about my less than appropriate response. I was in a hurry and back tracked only enough to get a hint of a clue (obviously I wasn't successful!) I definitely should have gone beyond, so I would have had a better understanding of the question.

My apologies!

However, I tend to stand by my comments. Once you have values in a vessel, there is generally little need to filter unless you are shooting for precipitation. My policy was to leave values in the container and siphon or pour solutions, with the exception of solutions that were filtered in preparation for precipitation.

Any time you get a filter involved, you have the problem of material being trapped in the filter, plus the time it can take for filtration, which can be prolonged if the material being processed hasn't been treated well. It can be avoided by not filtering unless it's necessary. It often is not.

If the discussion is revolving around platinum group values recovered from solution with zinc, nothing changes. I good wash with HCl, then several rinses, followed by a drying, much the same as with gold, is all that is required. Filtration is a waste of time and serves no real purpose.

Harold

hi harold

the bit you say about the link between gold is what i was thinking.....thanks the more times i do this the simpler it gets...

 

[jimdoc]

I have heard of some rare earth metals being used in converters,I will try to find the info to ad a link.

Jim

Cerium;

http://www.suite101.com/content/applications-of-the-rare-earth-elements-a186755

http://autocatalyst-recycling.umicore.com/catalyticConverter/

 

[pgm]

I have heard of some rare earth metals being used in converters,I will try to find the info to ad a link.

Jim

Cerium;

http://www.suite101.com/content/applications-of-the-rare-earth-elements-a186755

http://autocatalyst-recycling.umicore.com/catalyticConverter/

i would be carful of umicore.....i rang them a few times,....never can get a straight answer from them......waste of time...i think based on my experience