A long time ago there was a couple guys melting aluminum not far(maybe 20 miles) from here. I'm not sure how exactly they did it, only saw it from the road, but it was right beside the road. It was a tall cylindrical thing, maybe built with an old iron or steel tank or silo(if I remember right it wasn't very big around, 2+ft, maybe 3 or 4 at the most), I guess they'd throw the aluminum in the top. I think they used a propane tank to fuel it, and maybe some coal in the bottom. Sometimes they'd have quite a stack of bars maybe 6x8x24(not sure that either) out there.
If it was possible on side the road 30 years ago by a couple country dudes, you should be able to come up with something, although I'd guess the environmental effects would need be better considered today