# Unusual Crystals



## rusty (Sep 3, 2013)

Can anyone identify these strange crystals.


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## Harold_V (Sep 4, 2013)

Please describe the nature of the solution from which they grew. 

Harold


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## rusty (Sep 4, 2013)

Harold_V said:


> Please describe the nature of the solution from which they grew.
> 
> Harold



Sorry Harold that would be giving it away. PM Sent


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## rusty (Sep 5, 2013)

The crystals are aluminum sulphate from the dissolution of the catalytic substrate from milled cat comb.

As with most successful processes involving precious metals the material should be incinerated or roasted, in this case to eliminate carbon. After roasting the material is introduced to sulphuric acid which puts the honey comb into solution leaving nothing but the precious metals behind.

It's a tricky process in finding the sweet spot where your not over loading your acid with pulp ( milled cat comb ) overloading the acid the pulp will solidify into glop - much firmer than jello. Fortunately this glop is water soluble easily turned back into liquid.

Once the alumina has all been successfully taken into solution the precious metals now have nothing to cling onto have no choice but settle to the bottom of your reaction vessel from where they are collected then further treated in AR to separate the various platinum groups.


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## skippy (Sep 5, 2013)

The dissolution of honeycomb can never be total without hydrofluoric acid. Honeycomb is cordierite, which has silicon in its structure. HF is the only acid that can dissolve silica


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## rusty (Sep 6, 2013)

skippy said:


> The dissolution of honeycomb can never be total without hydrofluoric acid. Honeycomb is cordierite, which has silicon in its structure. HF is the only acid that can dissolve silica



Are you stating from personal observations from previous experiments. 

Experiments carried out by myself show that 90 percent of the honey comb subjected to this test has gone into solution from which it is easily decanted leaving as you say a bit of undissolved comb material behind with platinum group metals along with some carbon.

My biggest problem was trying to overload the acid with pulp in where the acid had exceeded the sweet spot for allowable pulp and had solidified via crystallization of the alumina.

Let us say I'm stating off with 100 lbs of milled cats, after removing 90 percent of the solids via sulphuric acid this leaves me with a mere 10 lbs of solids to deal with, bonus any nickel present would be removed. I do not think the use of HF is necessary.

Using this method to remove the bulk of the pulp would result is a much better PGM recovery over leaching the whole 100 lbs which we all know is horrible stuff to filter. As your aware I've experimented with a centrifuge built for this purpose long ago to extract the pregnant liquor from the leached pulp.

The centrifuge worked the few times I had used it but I had become worried over atomization, so I abandoned the project in favor of keeping my health.


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## butcher (Sep 6, 2013)

I am not sure of the conditions you are using the sulfuric acid. But I am wondering if you are leaching any Rh into the sulfuric acid leach.


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## skippy (Sep 6, 2013)

My conditions were different : concentrated sulfuric, fuming temperature, crushed instead of milled. I ended up removing about 25% of the weight or thereabouts. A finer grind and less concentrated acid would both probably have worked better to achieve your results, but that wasn't my goal. Your results are not what I would expect, but they interest me.


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## rusty (Sep 6, 2013)

butcher said:


> I am not sure of the conditions you are using the sulfuric acid. But I am wondering if you are leaching any Rh into the sulfuric acid leach.



It's very possible that trace amounts of PT, PD or Rh could go into solution, these could be cemented out with out any loss. Butcher i've never heard back or read any comments here on the forum regarding the lot of milled cat comb you purchased from me. Did you have any success recovering any precious metals from that lot or not.



skippy said:


> My conditions were different : concentrated sulfuric, fuming temperature, crushed instead of milled. I ended up removing about 25% of the weight or thereabouts. A finer grind and less concentrated acid would both probably have worked better to achieve your results, but that wasn't my goal. Your results are not what I would expect, but they interest me.



Removing 25% of the bulk alumina from the pulp would have been a Eureka discovery.

Sulphuric acid in its various concentrations each have their own characteristics, your right milled cat comb goes into solution much better than chunks of comb. In my first experiment as you did used chunks and came up with basically the same results you did but found that the remaining chunks were easily crushed after being subjected to the dilute sulphuric.

Before crushing I had the crystal growth, after crushing the larger pieces in the beaker my solution solidified, not to be discouraged added water which brought the glop back into solution. I let the insolubles settle out before decanting then adding fresh acid. My watered down decanted solution remains liquid while the fresh addition of acid to the reaction vessel has consumed more of the alumina.

What I've learned from this is that I have to approach these experiments in a more scientific manor.


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## butcher (Sep 6, 2013)

I still have the crushed catalytic converter material you sent me, I have not attempted a leach yet. 

I was hoping to get some more material to process with it, but here it is almost impossible to get catalytic converters, they have made laws of selling them because of the problems with thieves.

I suspect if you were strongly heating the catalyst with concentrated sulfuric acid, the solution would likely contain the Rhodium.


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## skippy (Sep 6, 2013)

Maybe dissolving the ceramic sufficiently turns much of the silica into a colloid that gets poured off too.


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## rusty (Sep 6, 2013)

Lou once referred to me as the forum bibliographer. http://goldrefiningforum.com/phpBB3/search.php?keywords=bibliographer 

It's very true I'm good at doing research, from this point forward my own interests come first.

Anyone wishing to participate and collaborate with me on this experiment is more than welcome to communicate privately with me. Just be aware that I may use the knowledge gained from our combined work to write a cheap skit of my own to publish for profit.


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## rusty (Sep 6, 2013)

skippy said:


> Maybe dissolving the ceramic sufficiently turns much of the silica into a colloid that gets poured off too.



Skippy depending on the catalytic's end use the alumina composition may vary.

Todays observations, the dilute decanted leach is still in a liquid state, crystal formation in the reactor is attached to the inside of the glass while the remainder of the leach remains free of growth.


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## skippy (Sep 6, 2013)

I put a lot of time and money into cats, and got pretty good at recovery, I never seemed to get to the point where I could make any money at it. Working with the large volumes that cats produce can be overwhelming. Handling the materials and solutions is at least a big a problem as a effective extraction. If there's a slam dunk way to deal with them I'd like to hear about it, and I like to read what other people are doing with them, but for me, the idea of messing with cats actually makes me kind of sick


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## skippy (Sep 6, 2013)

Looks like you might have PGMs in solution. Although I have seen a brown color that didn't produce any stannous result and the color disapeared on adding HCl
to the solution, with some VERY noticable chlorine production. My theory was that it was cerium (iv) sulfate from the wash coat, which is an oxidizer. Maybe rare earth recovery is also a possibility for aqueous methods...


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## Palladium (Sep 7, 2013)

rusty said:


> Lou once referred to me as the forum bibliographer. http://goldrefiningforum.com/phpBB3/search.php?keywords=bibliographer
> 
> It's very true I'm good at doing research, from this point forward my own interests come first.
> 
> Anyone wishing to participate and collaborate with me on this experiment is more than welcome to communicate privately with me. Just be aware that I may use the knowledge gained from our combined work to write a cheap skit of my own to publish for profit.



If your going to set up a website i would use Godaddy.


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## rusty (Sep 8, 2013)

No surprise the vertical crystal growth in previous post went back into solution as the sun warmed up the liquid.

Just an educated guess on my part, but i figure that 90 percent of the starting material dissolved into the weak sulfuric acid to where it could be easily decanted leaving some insolubles behind along with the platinum group metals which are now in AR. I had earlier on let the sediment settle out the color of the AR certainly indicates platinum is present.

If you research alumina you will find that it has many uses, from manufacturing refractory materials, purifying water to the addition to concrete with hundreds of other uses.


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## rusty (Sep 8, 2013)

The end results, nice clean platinum group ions.


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## skippy (Sep 9, 2013)

If you could find a waste treatment co. or maybe a hog operation that uses it, that might be the way to get rid of it or even make money on it, if you could satisfy them that is wasn't toxic (nickel or chromium levels could be likely culprits). Or that is doesn't have too much free acid, or what have you. 


If/when you neutralize it you will find that your solution is not really very liquidy anymore :lol: 
Turning that aluminum hydroxide goop into something useful is going to be really difficult! If i remember correctly the goop will eventually crystallize though after a long time ( ie many weeks, even months, maybe a year)


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## rusty (Sep 9, 2013)

skippy said:


> If you could find a waste treatment co. or maybe a hog operation that uses it, that might be the way to get rid of it or even make money on it, if you could satisfy them that is wasn't toxic (nickel or chromium levels could be likely culprits). Or that is doesn't have too much free acid, or what have you.
> 
> 
> If/when you neutralize it you will find that your solution is not really very liquidy anymore :lol:
> Turning that aluminum hydroxide goop into something useful is going to be really difficult! If i remember correctly the goop will eventually crystallize though after a long time ( ie many weeks, even months, maybe a year)



In the beginning my alumina pregnant liquid froze solid in the beaker,fortunately the alumina is water soluble easily put back into solution. if by chance precious and or nickel and chromium metals do find their way into the alumina leach they're easily cemented out using aluminum thus keeping the alumina in a pure state.


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## skippy (Sep 9, 2013)

What crystallized for you wasn't alumina, but aluminum sulfate. Alumina, if it crystallized out, wouldn't go back into solution with water addition.
I know I had a lot of trouble cementing nickel in my leach solutions. It wouldn't cement out until the solution was mostly neutralized. Aluminum sulfate is extremely acidic, and has little problem redissolving nickel or other base metals. It's interesting, the aluminum sulfate solution doesn't turn to goop until the the solution is practically neutralized (a pH of three or four IIRC). Basically, what this means is aluminum sulfate can give up a lot of its acid before the aluminum hydroxide starts coming out of solution. By a a similar token, an aluminum sulfate solution can provide a lot of acid to dissolve a lot of metal before it is spent, making cementing from a straight, full strength aluminum sulfate solution impossible. Anyways that's my understanding of it, one that I believe is correct, but i am sure at the least my phrasing is probably making our chemists cringe


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## rusty (Sep 9, 2013)

Getting serious about my belated education, http://www.science.uwaterloo.ca/~cchieh/cact/c123/separatn.html

The International Network for Acid Prevention http://www.gardguide.com/index.php/Main_Page


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## rusty (Sep 15, 2013)

This is from the last batch of cats processed in my reactor, tested with DMG - strange no paladium just some nickel, my stannous test clearly shows there's platinum present.


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## butcher (Sep 16, 2013)

rusty,
I do not know if your source material had palladium, or if you remembered reading this in Hoke's.

If the palladium is oxidized (in an incineration for example), it will not dissolve into aqua regia easily or at all. In Hoke's we learn the palladium oxide will dissolve in HCl. So in order to dissolve the palladium oxide into solution, Hoke suggests to add HCl first (to dissolve the palladium oxide) then add the nitric acid forming aqua regia to dissolve the other PGM's into solution with the palladium.


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## Harold_V (Sep 16, 2013)

butcher said:


> rusty,
> I do not know if your source material had palladium, or if you remembered reading this in Hoke's.
> 
> If the palladium is oxidized (in an incineration for example), it will not dissolve into aqua regia easily or at all. In Hoke's we learn the palladium oxide will dissolve in HCl. So in order to dissolve the palladium oxide into solution, Hoke suggests to add HCl first (to dissolve the palladium oxide) then add the nitric acid forming aqua regia to dissolve the other PGM's into solution with the palladium.


Excellent post, Butcher---and a great reason for readers to read Hoke's book. 

Harold


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## Geo (Sep 16, 2013)

catalytic converters reach a temperature that is well above the temps for incineration. i have the honeycomb from a few good size cats i have been planning on experimenting with. this is good information to note.


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## rusty (Sep 16, 2013)

This cat material was processed using hydrochloric acid / bleach for 8 hours at 100 degrees celsius in that enclosed 10 liter reactor using a condenser to reflux the fumes back into the reactor. I did not incinerate the milled up cat comb.

I'll do as you suggest butcher add the HCL first then heat it for an hour or more before adding the bleach, but then it is my intent to dissolve the comb in sulphuric acid before processing the fine black powder left behind.


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