Non-Chemical What is the best crucible for induction melting PGM's?

[DaniH]

What do you mean?
A crucible that heats in the magnetic field?
If so I think the only option is Graphite and that is not recommended with PGMs.
Depending on its intended use after that is.

So what form has the PGM?

Yes, my question was fir only self ignatiin, not for melting pgm, my mistake.

when we buy Here locally every seller says about his crucible that its graphite , when we install the crucible, it not self ignate, is there any mathod to pre chek if its graphite/ self ignating or not?

 

[4metals]

self ignating crucibles for induction.

Please translate this so we can answer the question.
Are you. melting platinum? Is your furnace a low frequency or a low frequency unit.

 

[4metals]

when we buy Here locally

Where is here?

 

[Yggdrasil]

Yes, my question was fir only self ignatiin, not for melting pgm, my mistake.

when we buy Here locally every seller says about his crucible that its graphite , when we install the crucible, it not self ignate, is there any mathod to pre chek if its graphite/ self ignating or not?

It would be nice if you used the correct terms.
Ignite is when something suddenly burst into fire.

You are using the crucibles as a suceptor I guess, heating the Crucible not the load.
https://en.wikipedia.org/wiki/Susceptor

What are you melting in the crucibles?

 

[DaniH]

Please translate this so we can answer the question.
Are you. melting platinum? Is your furnace a low frequency or a low frequency unit.

I am not melting pgms. Its for smelting ores.
Medium frequency induction furnance.

And self ignation was in sense of " a crucible that get heat by magnetic field, without need of any metal.

Donot knkw i am still able to explain. See pics

 

[DaniH]

It would be nice if you used the correct terms.
Ignite is when something suddenly burst into fire.

You are using the crucibles as a suceptor I guess, heating the Crucible not the load.
https://en.wikipedia.org/wiki/Susceptor

What are you melting in the crucibles?

I think you got me. I am smelting ore without any collecter metal

 

[Yggdrasil]

I think you got me. I am smelting ore without any collecter metal

Then you have a couple of options.
Cheapest and easiest is Graphite and a proper Crucible inside for the actual charge.
You will need proper High quality Graphite Crucibles (made out of proper Graphite) not some mix like carbide and such.
Make sure it is completely shielded from air, it will last longer then.
Or you can have a crucible made out of high temperature metal like Molybdenum or similar that holds the inner crucible.

What are the reasoning for smelting without collector metal.
There need to be sufficient metal in the charge to drag down other metals and form a pool in the bottom.

 

[4metals]

I use to melt gold in a #20 induction furnace using clay graphite. Occasionally the melt was small so we put another smaller clay graphite in the larger # 20. Often we turned on the power with the #20 in the furnace while loading up the smaller crucible. By that time the #20 was glowing red with nothing in it.

 

[Yggdrasil]

I use to melt gold in a #20 induction furnace using clay graphite. Occasionally the melt was small so we put another smaller clay graphite in the larger # 20. Often we turned on the power with the #20 in the furnace while loading up the smaller crucible. By that time the #20 was glowing red with nothing in it.

So it is the quality of the Graphite used, or maybe the setting of the furnace?

 

[4metals]

So it is the quality of the Graphite used, or maybe the setting of the furnace?

That is a question for somebody who manufactures crucibles! My experience comes from using, and abusing, them!

 

[DaniH]

Then you have a couple of options.
Cheapest and easiest is Graphite and a proper Crucible inside for the actual charge.
You will need proper High quality Graphite Crucibles (made out of proper Graphite) not some mix like carbide and such.
Make sure it is completely shielded from air, it will last longer then.
Or you can have a crucible made out of high temperature metal like Molybdenum or similar that holds the inner crucible.

What are the reasoning for smelting without collector metal.
There need to be sufficient metal in the charge to drag down other metals and form a pool in the bottom.

Using molybdenum as outer shell is good otion but i think it will put extra load on machine to get 1400+c inside crucible. Graphite is best option, but my question

Any mathod to confirm the crucible is of graphite or not?

In my local market, maximum people make crucible with carbon and clay. With old casting mathods. But sold as graphite. So i want a mathod to chek the material of crucible before buying, like ohms, cunductivity, resistance of crucible, or something like that

Purpose of smelting without collecter is to using mix ores , one ore has some metals to work as collecter and second have values.

 

[DaniH]

So it is the quality of the Graphite used, or maybe the setting of the furnace?

If its clay graphite, and using two crucibles one inside other work as most wide walls of crucible, so conductivity increase.

But my senerio is diffrent. I want use maximum space inside crucible.
A single clay graphite crucible will not behave like self ignating crucible

 

[4metals]

A single clay graphite crucible will not behave like self ignating crucible

In my experience a clay graphite crucible without anything in it did heat up. I only mentioned the smaller crucible in it because that was the only time the power was on with an empty crucible while loading the smaller crucible. Otherwise the crucible was loaded and the power turned up and there was no way to know if it was the charge in the crucible heating up or the crucible.

 

[DaniH]

In my experience a clay graphite crucible without anything in it did heat up. I only mentioned the smaller crucible in it because that was the only time the power was on with an empty crucible while loading the smaller crucible. Otherwise the crucible was loaded and the power turned up and there was no way to know if it was the charge in the crucible heating up or the crucible.

I think in such clay graphite crucibles, ghrapite content is more than clay and well mixed before casting. Here is claycarbon. And as i think these guys add carbon to only make its color black to make people fool,

A last experience is, a person sell us as graphite crucible, we test it with passing electrity to check its conductivity, and it allow current to pass.
When we install the crucible , it not self ignate,
Later we come to know, they use a graphite coating on clay crucible to make it conductive and make its color black.
Coating was of pure graphite.inner body was of normal clay
Drama everywhere

 

[DaniH]

In my experience a clay graphite crucible without anything in it did heat up. I only mentioned the smaller crucible in it because that was the only time the power was on with an empty crucible while loading the smaller crucible. Otherwise the crucible was loaded and the power turned up and there was no way to know if it was the charge in the crucible heating up or the crucible.

An electrode used in arc furnance are made of graphite?

 

[Yggdrasil]

An electrode used in arc furnance are made of graphite?

Yes

 

[Yggdrasil]

An electrode used in arc furnance are made of graphite?

But some may have coatings on them.
Are you planning to make a crucible?

 

[DaniH]

But some may have coatings on them.
Are you planning to make a crucible?

No, i am just looking to be not decieve, any mathod i can prechek graphit crucible as its actually graphite or not

 

[goldshark]

What country do you live in? A good brand is Salamander, but don't know if they are available there.

 

[Yggdrasil]

What country do you live in? A good brand is Salamander, but don't know if they are available there.

Do Salamanders heat in Induction?