Magnesium and Promethium are also ores, why should the furnace not be able to process them? Also except for iron, these are the ones that require the most mass-production
But a furnace should be able to process old, rusty metal, like steel plates, used weapons or tools, broken windows etc. It really puzzles me, why we should be able to process ores, but not scrap, whats much more simple.
Please let us not start with logic. It's a good idea most of the time to ignore would-be-logical rules if it helps gameplay.
Well, as far as Empyrion goes, it could use quite a bit more adherence to logic (weapon kits, anyone?). It's best to start with a logically consistent system and only modify those parts that would very negatively impact gameplay. In this specific case, it's not clear that there is a logical consistent model for the furnace to begin with.
After some more thought, I've decided I actually don't have a problem with the furnace not working for promethium and magnesium. Magnesium ore (ingame) is ground into powder, and promethium is processed into pellets which are then crafted. Neither is something typically associated with furnaces. Furnaces are associated with smelting ore into ingots, however, and that should be their only purpose.
Hm, if you really want to argue about this... Mg-Powder is made by melting Magnesia and spraying it into a cold, inert gas like Argon. You cant just rasp it into little pieces - it will burn away. Slowly, without an actual flame, but nevertheless there is little metal left after. So, in fact, to produce Mg-powder yo do need a furnace.
I found that you can edit template.ecf to have this to smell plates back to ore or any other items. File location : \SteamLibrary\steamapps\common\Empyrion - Galactic Survival\Content\Configuration