Below are a few pictures of an ancient smelter. I have been researching ways to make a smelter and these seemed fairly easy to build.
This smelter uses coke and forced air to produce the high temperatures needed for melting iron dust
This smelter is an older one that uses charcoal for the processing. This one is much simpler so I think I could build it easier than the coal one.
I am not sponsored by any of these companies nor do I now if they are all good. They are just a collections of sites I found where you can buy stuff