I discussed 'oxyacetylene' with my father, he suggests that. The flame, as you know burns at ~3300 C. I was wondering about its potential cost though?
Perhaps I could create a sort of blast furnace via coal and an 'air' source?
Edit: My dad was a welder years ago, before retiring. I guess that's part of his affinity for oxyacetylene, since he used the torches often in his work...