I know that in order to smelt stuff, you need to heat it until it melts and then pour it into a form. But that oven and that form always need to have a higher melting point, right? So how do we create the oven at the top? How do we create stuff when nothing with a higher melting point exists to make an oven out of it?
Edit: I think I understand now, thank you again to the kind people in the replies who explained it to me 🙂
In: Technology
Other people have addressed the crucible/casting form thing, but I want to address another misconception here:
Smelting isn’t just “heating things until they melt”. The thing you put into the smelter is an *ore* – not actually metal itself, but some sort of mineral with compounds that *contain* that metal. Iron oxide, iron sulfide, etc.
High temperature is important for making the metal at the end stage liquid so it can be poured off, but equally important to the smelting process is somehow making those other unwanted oxygen and sulfur and other atoms go away. For oxide ores especially, this means you need to add a *reductant* (aka *reducing agent*) to the ore in the smelter.
Carbon is historically the simplest and most ubiquitous metallurgic reductant, whether as charcoal or coke; it combines with the oxygen to form carbon dioxide that just escapes through the smokestack, leaving pure metal behind.
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