# How to melt palladium



## brjook

I tried and tried and all it done was sing to me .I know it absorbes oxygen and i tried to use as less as i could but no good .I don;t have access to a hydrogen torch so what to do?


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## Barren Realms 007

Here is a post Lou made that might help you out.



> Lou wrote:
> 
> Platinum bars are poured from zirconia crucibles that are "double bagged" inside an alumina crucible. The heavy wall alumina bears the weight of the ZrO2 crucible containing the Pt. Zirconia looses its strength after a few heats and must be replaced fairly often. Usually you have a "starter" plug or heal of platinum that soaks up the power because most melters are 10-12 kHz and won't heat powders for crap. Same thing for gold powder--most of the heat goes into the graphite or SiC crucible and melts it by conduction! It's a different story if you put a cylinder of gold in there. When the Pt plug melts you can add the sponge platinum. I much prefer to have not melted the material but have the sponge sit upon the bulk metal and heat, that way any moisture is steamed off.
> 
> Pd is much of the same, except atmosphere control is more important as it is considerably more gassy than platinum.


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## brjook

Thanks for the post but it didn't really help me any.All i was asking is there a way to melt Pd without a hydrogen oxygen torch?


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## Harold_V

brjook said:


> Thanks for the post but it didn't really help me any.All i was asking is there a way to melt Pd without a hydrogen oxygen torch?


It can be melted with an oxy/acetylene torch, or natural gas and oxygen. I expect that you'd have difficulty with most other methods due to the relatively high melting temperature. Hydrogen is the recommended fuel, which eliminates the risk of forming carbides. 

Harold


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## brjook

I got a oxy/Map gas tourch i use to melt gold with no problem.When i try to melt the Pd all it does is swell up and make a high pitched whinning sound the more i heat it .I tried to turn down the oxygen but it wouldn't melt it then .I have some 1 inch crucibles .Could i heat the outside of the crucible and not put the flame on the Pd .Would this work?


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## samuel-a

MAPP = MethylAcetylene-Propadiene Propane, this is a carbon based fuel, kind of a no no for Pt/Pd

I also find it hard to believe you can reach sufficient temperature for melting Pd just by heating the crucible.


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## Harold_V

brjook said:


> I got a oxy/Map gas tourch i use to melt gold with no problem.When i try to melt the Pd all it does is swell up and make a high pitched whinning sound the more i heat it .I tried to turn down the oxygen but it wouldn't melt it then .I have some 1 inch crucibles .Could i heat the outside of the crucible and not put the flame on the Pd .Would this work?


I expect your problem is more rooted in lack of BTU's than temperature. Are you using the largest tip you have at your disposal? If you are, and you can buy an even larger one (rosebud, for example), that would likely work. I melted over a troy ounces of platinum with such a tip, using natural gas and oxygen. While I'm not sure I'm right, I expect that MAPP gas has much higher potential. 

You likely can't melt by heating the crucible. There's too much heat being lost to the atmosphere. It likely would work in a furnace, however, but achieving that temperature is not easy. Induction is really the way to go for these metals, but it's somewhat out of reach for the hobbyist. 

Harold


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## brjook

Thanks for the info Harold .I guess i will have to get a bigger tip .The one I am useing works great for gold but if i am going to do Palladium also i just rite if off as ths cost of advanceing .Also where can you sell palladium at ?


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## butcher

The noise popping and hissing can come from overheating the (too small) torch tip, ignition of gasses inside the torch.


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## Harold_V

brjook said:


> Also where can you sell palladium at ?


I'm likely not a good person to ask. My experiences in selling both my platinum and palladium left me with a very bad taste in my mouth---and I had a lot of each to sell. 

You may find that Lou is willing to buy, but please understand that I am not speaking for him. I would recommend him highly if he's interested, however. 

Harold


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## Lou

*I'll buy your palladium.* Don't bother melting it. It's easier for me to take a sample of the powder and run ICP-AES on it that way. 

If you're trying to melt it, get a high back alumina crucible and preferably go at it with an oxyhydrogen torch. Any oxyfuel torch will easily make enough heat to melt platinum or palladium. It just depends on tip and flow rate. That's why I recommend a high back alumina melting dish so that it's much harder for your powder to blow away. 

The reason why, the true reason, that carbon-based fuels like MAPP, acetylene, propane, and natural gas aren't recommended is this:

Palladium oxidizes. Platinum does not. You can usually get away melting platinum with oxyacetylene if you keep it lean at all times. You can't with palladium. Palladium has a problem that's kind of like silver's--it absorbs oxygen and fuel gases when molten and tends to spit if you don't know what you're doing. Remember well that these metals are catalytic--so any gas in a rich flame that hits the palladium is going to be split into hydrogen and carbon on the surface of the palladium. The carbon will migrate into the piece and give it a shiny gray-black look. Palladium has to be cooled below red heat in a reducing flame, and the only flame suitable for that is a hydrogen flame.


Lou


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## 9kuuby9

Would a HHO generator jewelry welder do the job?

It has quite a low flow rate of 95l/h or 1,6l/min.

This is what I'm referring to http://www.aliexpress.com/item/BT-3...Hydrogen-Water-Welding-Machine/372508030.html

Since it has a low flow rate would it be able to melt half a Troy ounce of Pd or Pt?


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## Dan Dement

BR,

I am a Manufacturing Jeweler and cast and melt Pd everyday. Lots depends on several things: 1, What form is your Palladium in, Metal or sponge? 2. What are going to do with it after you melt it? Sell it or try to make jewelry? What we use is a 5kw Vacuum, Centrifugal, Induction Melter. Two major problems, first if it is in Powder or sponge, an Induction Melter is not going to melt it as the crystal structure is too small and it passes thru the powder and goes back into the coils of your $30,000+ induction melter. Nothing like frying the coils of a $30,000 machine to keep you from making the same mistake twice. If that sounds like experience talking, it is ! If it is metal form, unless you melt in under Argon or a strong vacuum, you will embrittle the metal and it will be crack to high heaven and be useless for jewelry. In order to melt with a torch, Most Platinum is Torch melted using Hydrogen & Oxygen which just happen to be the elements that Pd absorbs when hot. 

Bottom line, If you got Palladium and you want to convert it to cash, send it Lou as he is the true expert and honest nice guy. The PGM's are best left to the guys that do it everyday and have the hundreds of thousands of dollars of equipment and know how to use it. Just some friendly advise from a guy who does it everyday.

Dan


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## JHS

I have no idea if this would work,or not.feel free to pick it to the bones.
I watched a documentry on net flicks about making carbon steel for viking sword.
they made a crucible of red clay,added the iron, carbon,and other materials.then sealed the crucible with more red clay.let it dry,then placed it in a wood fired furnace.used bellows to produce the required heat,and made carbon steel,in order to duplicate a sword.if the same air tight crucible were used to put pd in,and put in a furnace,would it work to melt pd?
john


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## Lou

Thanks for the recommendation, Dan (and Harold earlier on). I do appreciate it.

I've had the great fortune of working with Mr. Dement on palladium and its alloys and can say that it is a bugger to get right.

Here are the chief issues with palladium:

1. Forms an oxide before red heat (so called "peacocking")
2. Oxide disproportionates back into Pd and oxygen at higher temperature but reaches an equilibrium concentration of oxygen dissolved in the metal.
3. If you try to melt it under reducing conditions, the palladium can react with many of the refractories used in the crucible.
4. It is incompatible with carbon/graphite, silicon carbide, silica and to a lesser extent zirconia. 
5. It should not be melted with carbonaceous fuels.
6. Even if you take care to melt the Pd with oxyhydrogen, you will still get a gassy metal unsuitable for jewelry castings.

It's an interesting metal. I can melt up sponge in a small LECO crucible into a button, cool it under hydrogen and get a shiny button, but have it not be fully dense due to all the hydrogen it absorbs. Melting it with a neutral or lean flame and it sparks all over. 

Take home message: it shouldn't be torch melted. I think the only way to melt the powder reliably is a higher frequency vacuum induction furnace, preferably one where the power is ramped up slowly while pumping down. Too much power and the powder can fly out of the crucible. Too fast a heat up and any oxygen and/or hydrogen present will react with the metal.


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## 9kuuby9

Thank you all of you for the recommendation & practical information! :mrgreen:


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## samuel-a

Here's a good demo of how not to melt Pd...
See from: 5:20
[youtube]http://www.youtube.com/watch?v=r9sTVx_YV5A[/youtube]


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## g_axelsson

Cool video Sam, that's what I would call a "pipe"! :mrgreen: 

Göran


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## maynman1751

Hey Sam! Looks like you made a special trophy with a little puppy dog standing on his hind legs. Why did it erupt like that?


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## Lou

It erupted like that due to oxygen.


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## samuel-a

P.s. - it is not my video.

P.p.s - just imagime what would have happend if it were melted under H2 :O


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## Lou

No, it's Bob's video from RDO and was more proof of concept. He's more than fine to melt Pt that way but Pd can't be melted in that fashion and now that lot is a refining lot due to it picking up O. 

And actually Sam, you can melt the Pd under an H2 atmosphere so long as it switches over to Argon or Vacuum later on. A mix of H2/Ar is often used for this (and for sintering refractory metals, like W, Ta, Zr, etc.).

It's interesting that he got the powder to couple in his machine, usually you have to use what's called a "Briquetter" or else add copper and/or starter plug. This has everything to do with the frequency of the machine--higher frequency, less penetration, more skin effect. That's ideal for powders.


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## samuel-a

Lou,

What about Hydrogen absorbtion? When you melt Pd under H2 and switch to inert gas, did you notice a change in volume or spitting ?

I have seen on another video by him, of which they melt Pt and took a snap shot of the control panel, frequency was 387KHz... I reckon it is high enough (to say the least) for fine powder.


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## allenp

Hi all,
Greetings from Western Australia. We routinely melt Palladium and Platinum in a water cooled copper hearth or in large cupels using a 2500 Watt TIG torch. We can melt up to 10 ounces at a time. The argon flow seems to eliminate the Oxygen and the Palladium is readily workable. If you remove the TIG torch while the Palladium is still molten then it behaves as mentioned.


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## Dan Dement

Some poor jeweler is going to buy this and make jewelry out of it and it is going to crack to heck. Ever wonder why most jewelers hate Palladium? This is the answer.
Dan


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## danieldavies

hi all.
is it ok to pour liquid palladium into cold water to stop hydrogen and oxygen attacking it? or will it react with the water? thanks


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## Lou

I wonder. I do not know.

All of the palladium casting grain I've seen from JM has a slight pink hue to it, indicating that at least some oxidation is occurring when shot into water.


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## Alentia

I would strip of engineering degree and put him in prison for life endangerment the person who ever thought making those tongs from pliers using totally opposite laws of physics.

On another hand, if Pd shots are dropped into "acid" water from Water Ionizer, which is I believe mainly HOCl, should reduce absorption of oxygen to minimum.


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## Autch97

Hello,

I know this is an older thread, but I thought I should add my observations. I am a metallurgist who works at a company that deals with precious metal alloys. If you melt Pd in air and pour into a mold you will essentially get a metal foam because of all the O2 absorbed from the air and this is dangerous for the melter I have tried the following things:

- Forming Gas Cover: Some spitting at the surface. After casting the metal foams.
- Carbon Monoxide Flame Cover: No spitting. After casting metal foams.
- Natural Gas Cover: Lots of spitting. No foaming after casting. Ingot was melted and poured twice. Before and After the second melt IGA was performed. The carbon, oxygen, and hydrogen levels changed (respectively) from 15ppm , 27ppm, 1ppm to 62ppm, 17ppm, 1ppm. The fact that carbon went up while oxygen went down indicates that the carbon from the natural gas acted as a deoxidizer. The density of the ingot was 99.8%.

I know Pd will precipitate out graphite causing a grayish color if the carbon level gets too high, but this isn't a problem for a 62ppm carbon level because based on the phase diagram the practical solubility limit is roughly a 1000 ppm.

Anyways I'm new to this forum and I wanted to contribute this info. 

Autch97


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## Lou

Thanks and welcome to the forum! Your expertise and experience is valued here!


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## samuel-a

Welcome in Autch97.
Happy to have you with us.


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## saadat68

Hi 
If I have some cemented palladium or platinum
Can I mix them with some lead metal or lead oxide and melt them to get an alloy and send the alloy for fire assay/cupellation and get a piece of palladium instead of powder and sell it ?! :shock:


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## anachronism

How much are we talking about here ?


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## saadat68

For example 100 or 200 grams

Edit: They don't add whole of bar to cupel, They add just a small sample. Right?


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## Joshb08

Lou said:


> *I'll buy your palladium.* Don't bother melting it. It's easier for me to take a sample of the powder and run ICP-AES on it that way.
> 
> If you're trying to melt it, get a high back alumina crucible and preferably go at it with an oxyhydrogen torch. Any oxyfuel torch will easily make enough heat to melt platinum or palladium. It just depends on tip and flow rate. That's why I recommend a high back alumina melting dish so that it's much harder for your powder to blow away.
> 
> The reason why, the true reason, that carbon-based fuels like MAPP, acetylene, propane, and natural gas aren't recommended is this:
> 
> Palladium oxidizes. Platinum does not. You can usually get away melting platinum with oxyacetylene if you keep it lean at all times. You can't with palladium. Palladium has a problem that's kind of like silver's--it absorbs oxygen and fuel gases when molten and tends to spit if you don't know what you're doing. Remember well that these metals are catalytic--so any gas in a rich flame that hits the palladium is going to be split into hydrogen and carbon on the surface of the palladium. The carbon will migrate into the piece and give it a shiny gray-black look. Palladium has to be cooled below red heat in a reducing flame, and the only flame suitable for that is a hydrogen flame.
> 
> 
> Lou


Lou I have a ton of polladium I'm looking to sell, would love to speak to you regarding this.


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## Yggdrasil

Joshb08 said:


> Lou I have a ton of polladium I'm looking to sell, would love to speak to you regarding this.


The post you reply to is very old so depending on factors only Lou can reply to, it may and may not be valid any more.
I guess the “ton” is a matter if speech, use precise information please. 
Is it 1kg -10kg or 1000kg? 
Sorry I’m a metric guy and relate best to metric dimensions.

Just a heads up and good luck.


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## Ultrax

Harold_V said:


> You likely can't melt by heating the crucible. There's too much heat being lost to the atmosphere. It likely would work in a furnace, however, but achieving that temperature is not easy. Induction is really the way to go for these metals, but it's somewhat out of reach for the hobbyist.
> 
> Harold


You can heat closed(!) small cylindrical graphite crucible with MMA welding machine with carbon electrodes. It should be fast enough to avoid boiling of metal (electric arc has 6000 C) so you need to practice, but it is possible to successfully melt Pd


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## Yggdrasil

Ultrax said:


> You can heat closed(!) small cylindrical graphite crucible with MMA welding machine with carbon electrodes. It should be fast enough to avoid boiling of metal (electric arc has 6000 C) so you need to practice, but it is possible to successfully melt Pd


Harold do not frequent the forum much these days, he has "retired".


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## Ultrax

Ok, I understand. Perhaps my small experience with fast Pd melting will be useful to other members


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## Yggdrasil

Ultrax said:


> Ok, I understand. Perhaps my small experience with fast Pd melting will be useful to other members


Of course it may be useful, I merely pointed to this fact so you did not expect an answer from him.
Have you actually tried this?
I thought Pd was like Pt and did get brittle and contaminated by Carbon?
Maybe I'm be wrong though


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## Ultrax

To be honest, I didn't test how brittle it is, but the powder melted into a drop successfully. But I think you're right , an oxidizing atmosphere is needed. For one single melt, a temporary thin magnesite coating can be made inside a graphite crucible.


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## orvi

Yggdrasil said:


> Of course it may be useful, I merely pointed to this fact so you did not expect an answer from him.
> Have you actually tried this?
> I thought Pd was like Pt and did get brittle and contaminated by Carbon?
> Maybe I'm be wrong though


I do not know about platinum, but Pd and definitely Rh form "alloys" with carbon. Palladium melted in graphite is dark in colour. Few times, our PGM alloys melted in graphite crucibles sticked to the walls and they needed to be chisled out - so yeah, carbides are real  All in all, without vacuum furnance you will likely obtain metal foam.
I had good experience with melting in quartz dish in induction furnance. Foam as expected, but allright for selling. As long you do not "switch" to the reducing enviroment (eg touch/stir with graphite rod, blow oxy/fuel flame over or pour it into the graphite mold), you will obtain relatively nice - altough foamy - button. It also tend to spit when you do this


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## Yggdrasil

orvi said:


> I do not know about platinum, but Pd and definitely Rh form "alloys" with carbon. Palladium melted in graphite is dark in colour. Few times, our PGM alloys melted in graphite crucibles sticked to the walls and they needed to be chisled out - so yeah, carbides are real  All in all, without vacuum furnance you will likely obtain metal foam.
> I had good experience with melting in quartz dish in induction furnance. Foam as expected, but allright for selling. As long you do not "switch" to the reducing enviroment (eg touch/stir with graphite rod, blow oxy/fuel flame over or pour it into the graphite mold), you will obtain relatively nice - altough foamy - button. It also tend to spit when you do this


If you have an inert atmosphere there will be no foaming I believe.
For instance, Argon covered melt.


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## Yggdrasil

orvi said:


> I do not know about platinum, but Pd and definitely Rh form "alloys" with carbon. Palladium melted in graphite is dark in colour. Few times, our PGM alloys melted in graphite crucibles sticked to the walls and they needed to be chisled out - so yeah, carbides are real  All in all, without vacuum furnance you will likely obtain metal foam.
> I had good experience with melting in quartz dish in induction furnance. Foam as expected, but allright for selling. As long you do not "switch" to the reducing enviroment (eg touch/stir with graphite rod, blow oxy/fuel flame over or pour it into the graphite mold), you will obtain relatively nice - altough foamy - button. It also tend to spit when you do this


In jewelry, Pt has to be soldered with a strongly oxidizing flame to avoid brittleness.
Preferably Hydrogen flame.


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## orvi

Yggdrasil said:


> If you have an inert atmosphere there will be no foaming I believe.
> For instance, Argon covered melt.


I believe that it would be significantly lower than that of oxygen or hydrogen - due to relatively obvious reasons. But it will definitely has some solubility. Never tried this, as I do not have proper equipment in hand.


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## Yggdrasil

orvi said:


> I believe that it would be significantly lower than that of oxygen or hydrogen - due to relatively obvious reasons. But it will definitely has some solubility. Never tried this, as I do not have proper equipment in hand.


If I'm not mistaken. The foaming and spitting of both Silver and Pd comes from its affinity for Oxygen.
So if you deprive it from Oxygen it should behave.


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## orvi

Yggdrasil said:


> If I'm not mistaken. The foaming and spitting of both Silver and Pd comes from its affinity for Oxygen.
> So if you deprive it from Oxygen it should behave.


Yeah, it can be rationalized like that. It tend to adsorb oxygen, because it can bind it temporarily in the melt, easy saying. Strange and fascinating metals


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