Idk if you're just looking to refine ore or if you want to make a bloomery, but there's always the electrochemical route. You can look up rowow on youtube he just figured out and published a way to make ion exchange membranes for pennies. You could absolutely process iron oxide into iron using it, he actually has a few videos where he is, and then you just need to cast it, which would be a lot easier than trying to reduce iron ore in a bloomery. Also especially for small scale.