How do you get an electric furnace hot enough to make various molten metals without all the heating equipment melting? Elon was saying that they would use hydrogen for carbon free high temperature metallurgy. Does this technology replace that?
https://en.wikipedia.org/wiki/Induction_furnace
https://en.wikipedia.org/wiki/Electric_arc_furnace
https://en.wikipedia.org/wiki/Zone_melting
Their thing is a fancy version of the induction furnace.
Also there is refractory and then there is refractory
https://chemistry.fandom.com/wiki/List_of_elements_by_meltin...
For instance Tungsten melts at 3407 °C, Platinum at 1772 °C, Iron at 1535 °C, Aluminum at 660 °C and there are all sorts of refractory oxides, carbides and nitrides so you can find something to make a vessel out of to hold most metals, if it is hard it is usually not the temperature but the chemical reactivity, e.g. Titanium wants to dissolve almost anything you try to melt it in which is more of a problem for keeping your Ti pure than it is maintaining the container's integrity.
If you look in a chemistry book you'll see most metals can be reduced from oxide ores easily with hydrogen in the lab, the other reagent that commonly works is carbon monoxide, which is what is used in a blast furnace for reduction of iron. Another approach to "green" iron refining is to use carbon monoxide like a conventional blast furnace but capture the carbon dioxide in the exhaust and recycle it by cracking it down into carbon monoxide again.
Anybody doing "green" processing of ore at this scale yet?
https://en.wikipedia.org/wiki/Open-hearth_furnace
invented by
https://en.wikipedia.org/wiki/Carl_Wilhelm_Siemens
whose younger brother
https://en.wikipedia.org/wiki/Werner_von_Siemens
started the famous electrical equipment conglomerate. Previous to that the bit for a horse cost more than the horse and steel was expensive enough that a historical "sword" seemed more like a "knife" by our standards.
But there's plasma heating, arc furnaces, induction heating, infrared, resistive heating, heat pumps, etc. You can cover anything from thousands of degrees to (more commonly) hundreds of degree with these. Some steel plants already use arc furnaces or induction heating to melt the steel.
I'm not sure where this technology sits but it all boils down to cost and effectiveness. If it works as advertised, companies will use it.
The thing with green hydrogen is that you need even more electricity to generate it. Which makes some of these alternatives more economical because you can use the electricity directly at a higher efficiency.
Electric arc furnaces are used for around 30% of global steel production
https://en.wikipedia.org/wiki/Steelmaking#/media/File:Evolut...