Ceramic Catalytic converter smelting

Hi

After a long due, I finally had the time to try smelting a ceramic cat converter.


I crushed then milled the sample cat which weighs 750 grams.

Took a 13.28 gram fine ceramic cat and placed it in a melting dish.


For process I used 168.6825 grams (5.950 oz) lead, which 18.8811 grams (0.666 oz) silver shots were added while it was molten.

The reason oz was used so once this process is finished any traces of PGMs collected by lead silver alloy from the cat can be detected.

I placed the lead-silver alloy on top of fine ceramic cats and melted it, my plan was to melt the lead alloy as it pours down the dish fine cat materials are coming to the surface and during this transition micro sized PGMs are collected.

As lead silver alloy melted at first nothing showed on the surface but few seconds later tiny pieces of fine ceramic cats came to surface of molten lead.

I used a stainless steel rod to stir the fine cat at beneth the molten lead as they came to the surface.

So I poured the molten lead silver into a mold, most of it poured there was a piece left in the dish as fine cats were stuck to it. It can be seen in the following;


This was what was left after I removed the molten lead.


Next I am going to cupel the lead bead, and weig the silver button also dissolve it to see if and what PGMs did it collect from ceramic cats.

Eventuallly I will take the fine to the shop where we will smelt them using our stationary furnaces which is basically working like a large melting dish.

I will also test small sample of this cat smelting with sodium bisulfate as it was briefly discussed by a member.

Best regards
KJ

Here is some updates on my adventure smelting ceramic cats.

Got a silver alloy after cupelation of lead, dissolved it in nitric acid, it seems very small Pd in solution and what seems like Rh powder.



And possible Rh powder


These Pd and Rh came from just three teaspoon of fine cats.

I will drop the Pd and dissolve the possible Rh using hot concentrated acid to confirm it is Rh.

Keep you posted

New updates

I cemented the black powder from yellow solution in previous post by zinc.


Since the content of silver used in smelting exceeded 75% and PGM content was only trace, any Platinum would have been dissolved in nitric acid along Palladium.

So I dissolved the black powder in warm dilute nitric acid, got a very pale yellow solution and grayish powder which settled at the bottom.

Pd nitrate solution


Garyish residue (possible Rhodium?)


That gray residue in filter paper


More pictures in next post

I rinsed the gray powder into a beaker and decanted its water, added concentrated sulfuric acid, I didnt see any immidate reaction so I let it simmer for half and hour, I am guessing dissolving Rhodium in sulfuric acid takes a lot longer. Please advise.

For Palladium nitrate solution I used DMG, this is as soon as it was added to Palladium nitrate solution.


The DMG salts seem like redissolving back,


Filtered the DMG salt which by the end of filtering only small amout remained. Here is the black powder


So far this is the result from lead smelting only 3 teaspoon of fine ceramic catalytic converter.

It seems I was able to recover Palladium and possibly Rhodium.

Will continue smelting the rest of the fine powder and keep you posted.

Thanks
KJ

The amount of PM's expected from 1 converter is very few grams. Hence you used too much lead and silver and this is not a worthwhile method

Hi

The purpose of the primilary test was to see if I can recover palladium and rhodium.

The charge I used was only 3 teaspoon and expected PGM from that much is very little.

I am smelting all 750 gram fine powder this week using our bigge furnaces and post pics.

I like to try lead smelting cats to see if our method here work or not.

Thanks
KJ

Hi,

I took a 4 gram sample from the fine ceramic catalytic converter, and heated in concetrated sulfuric acid for an hour. Result is a very pale yellow solution as it can be seen here.

4 gram sample ceramic cats


Heated in concetrated sulfuric acid


Comparison between just concetrated sulfuric acid color on the left, and sulfuric acid heated with ceramic cats on the right.


To be sure solution on the right contains rhodium, I need to pour it to large volume water, then test it with stannous chloride, which is coming up next.

I am also waiting for my cryolite to arrive, so I can give the whole thing is a smelting.

Thanks
KJ

Hi

Took a 50 gram sample of milled cat from this thread. Mixed it well it with 50 grams of cryolite. Smelted it with lead silver.

Got 0.21 grams of Platinum black, 0.02 grams of Palladium black, and what it seems 0.01 Rhodium, that makes PGM content for this specific ceramic cat to be 3.1 grams of Pt, 0.3 gram of Pd, and 0.15 gram of Rh.

I tried to smelt the rest of 700 grams, but due to some accidents it was a failure.

Here are some photos;

Silver shots from cupelation


Rhodium powder from dissolving silver shots in nitric acid


Palladium nitrate, and Platinum black not soluble in nitric at the bottom.


Palladium black percipitated from nitrate solution


And finally this is the slag, which seemed to have dissolved all the fine ceramics.


I have another 388-gram ceramic cat, different car, which I will smelt and post result hopefully without any accidents.

Best regards
KJ

Hi

I knew about using lead cupeling, it can melt and purify silver, gold.

This was my first try lead cupeling with palladium black powder, which resulted in a bead weighs so small that my scale doesnt show.

Under the lope it shows the shining palladium metal.


This proves to be an efficent and loss free way of melting small or large quantity palladium.

Thanks

Is reductive atmosphere to avoid Pd blackening can be spared in this situation?

I dont see any black spot under the lope, but I know for a fact cupeling silver powder will have some losses.

Hi

I am processing a batch of old telephone switchboard. It was positive for palladium.

I had a copper nickel palladium nitrate solution which I used the standard DMG solution to drop Pd.

It percipitated as green color first but after filtering and washing it becomes different color than yellow.

Here is a picture


In an acidic nitrate solution which is positive for palladium, does DMG percipitate other metals? Besides Pd?

My experience is that rhodium, silver, platinum even gold will follow palladium in precipitate if present. Also base metals from solution and adjacent precipitates should be deleted to avoid their joining. Red tint may be of course nickel but also iron

Thanks Lino

I have always get yellow DMG Pd salt when using it to drop from nitrate solution.

This is very first time even after washing I get this pink purpule color salt.

I cemented this DMG salt with zinc powder and it produced grayish residue which easily dissolved in nitric acid and solution was clear.

Added hcl to that solution and a white yellow cloud formed which resembled silver chloride however it didnt turn purple under the light.

Nickel will percipitate using DMG only in allaline condition, based on what I have learned here.

Thanks and regards
Kj

"easily dissolved in nitric acid and solution was clear." At that point I would check for silver (or lead) with K2Cr2O7. Wash the sediment obtained with HCl and check liquid for Pd

All

I smelted a connector from the telephone switchboard and got 0.37 gram of palladium.

Here are the pictures


Here is the close up shot from back


Here is the front


There are over 100 pieces of slots to be processed, it seems that smelting is the only way to process them.

Stay tune for result and pics of the switchboard

CORRECTION
After dissolving the above bead in warm dilute nitric acid, I got silver nitrate only so this was only silver.

It is unusual since the card I tested with DMG had yellow Pd DMG salt so connection would be the same material, but that is not the case

Here is the telephone switchboard and the card that was positive for Pd.

I dissolved the slots in previous post, dropped the silver as chloride, and solution with stanous chloride test shows yellow as seen in pictures below,

My intreption of stannous result is Platinum, but never seen a silver alloyed or plated with Platinum.

Please advise




Please note the solution is blue but stannous turns that into yellow as seen.

If is Pt, adding DMG would precipitate Pt also based on my understanding.

Here is a drop of solution before adding stannous chloride test


This is stannous chloride solution addition

No suspicion for copper in addition?

Hi Lino

So you mean does solution turn yellow if copper is presented? The majority of solution is copper.

How did you smelt it? In lead?




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