[eric2011 (OP)]

Hi Hope everybodh has a good day. I have a furnace that runs up to 1000 C I would like to melt cast iron but its melting point is higher than that. Does anybody knows what chemical element I can add to the cast iron in the crucible that can help to reduce the melting point of iron to under 1000 C? I will appreciate an answer.

Thanks

[Bored chemist]

Anything that did so would stop it being cast iron.

[eric2011 (OP)]

Anything that did so would stop it being cast iron.

Sure it doesnt matter if it changes to something new but what chemical elements I can add to reduce its melting point?

[evan_au]

This page has a phase diagram, showing the lowest melting point (eutectic) alloy of iron and carbon having a melting point of 1130C.
https://www.tf.uni-kiel.de/matwis/amat/iss/kap_9/backbone/r9_5_1.html

Later pages in the series mention the impact of other elements like silicon and phosphorus.

[Bored chemist]

Anything that did so would stop it being cast iron.

Sure it doesnt matter if it changes to something new but what chemical elements I can add to reduce its melting point?

If it does not matter what you get then why use iron?
Why not use (as an example) aluminium?

[alancalverd]

Fe-Sb eutectic is around 750 deg C.

[eric2011 (OP)]

Fe-Sb eutectic is around 750 deg C.

What is Sb? I know iron is Fe. And do you know Fe-Sb mixture composition? In percentage

[chiralSPO]

Sb is antimony.

According to the engineering toolbox (https://www.engineeringtoolbox.com/iron-alloys-melting-points-d_1436.html)

It's about 94% Sb, 6% Fe (so that's essentially Sb with some small contamination of Fe...

Also, from what I can find, the melting point of pure Sb is lower that reported by the engineering toolbox (and alancalverd), which doesn't make much sense to me.

[eric2011 (OP)]

Thanks guys. I asked all this because I saw a guy wrote somewhere that if you mix iron and carbon, melt it and annael for a period of time you get diamond powder. Thats what I am trying to experiment. Anybody has tried this?

[Bored chemist]

I saw a guy wrote somewhere that if you mix iron and carbon, melt it and annael for a period of time you get diamond powder.

I doubt that.
Diamond is normally formed at enormous pressures.

[evan_au]

you get diamond powder

Carbon is very soluble in iron.
- Of the different allotropes (forms) of carbon, diamond is stable at high pressures (like > 150km beneath the surface of the Earth). At sea level pressures, graphite is more stable, so diamond is thermodynamically encouraged to slowly turn into graphite (although you can reduce the rate by cleaning it in hydrofluoric acid, with ties up a lot of the loose ends with fluorine atoms)
- One other allotrope is carbon nanotubes, and these have been formed by having tiny iron "seeds", which grow carbon nanotubes.
https://phys.org/news/2012-11-optimize-growth-individual-carbon-nanotubes.html

[Bored chemist]

Of the different allotropes (forms) of carbon, diamond is stable at high pressures (like > 150km beneath the surface of the Earth). At sea level pressures, graphite is more stable, so diamond is thermodynamically encouraged to slowly turn into graphite

It's important to realise what that means.
If you dissolved some diamond in molten iron, then let it crystallise out, what you would get would be graphite.
Unless you are working at enormous pressure, the reaction "goes the wrong way".

[evan_au]

tiny iron "seeds", which grow carbon nanotubes.

What seems to be happening here is that the graphite forms at the outer edge of the "seeds". Because the outer edge is a closed loop, the graphite also forms in a closed loop, generating a carbon nanotube (tubular graphite).

[eric2011 (OP)]

I was reading about synthetic diamonds in wikipedia and in the history section I came up to this paragraph:

After the 1797 discovery that diamond was pure carbon,[2][3] many attempts were made to convert various cheap forms of carbon into diamond.[4][a] The earliest successes were reported by James Ballantyne Hannay in 1879[9] and by Ferdinand Frédéric Henri Moissan in 1893. Their method involved heating charcoal at up to 3,500 °C (6,330 °F) with iron inside a carbon crucible in a furnace.

There it is mentioned that they heated charcoal to temperature of 3500 C so my questiion is how possible is it to produce that kind of heat with charcoal?

[Bored chemist]

how possible is it to produce that kind of heat with charcoal?

They didn't use charcoal to heat the furnace. I think it was an electric furnace.
The charcoal was an ingredient, not the fuel.

[JesWade21]

The danger of smelting steel is orders of magnitude greater than that of smelting aluminium or bronze. If you spill liquid iron on yourself, it will burn through your clothes, flesh, and probably all the way into the floor.

Protective gear is important, but safe equipment and handling practises should be your top priority, because if those fail, it won't matter what kind of boots you're wearing.

[Bored chemist]

The danger of smelting steel is orders of magnitude greater than that of smelting aluminium or bronze. If you spill liquid iron on yourself, it will burn through your clothes, flesh, and probably all the way into the floor.


Protective gear is important, but safe equipment and handling practises should be your top priority, because if those fail, it won't matter what kind of boots you're wearing.

Thanks for clarifying your level of ignorance.
Molten Al or bronze will also burn through flesh.

As a technicality; can you smelt steel?