Concerned about low local iron production from ore, and about the cleanliness of the traditional methods, I propose here a cleaner iron smelting process.
When any of the iron oxides are heated in an atmosphere of methane gas, the carbon and hydrogen of the methane strip the oxygen from the iron, leaving metallic iron. These reactions occur most reliably at 800C and above, so the oxide and or gas have to be heated.
I propose an iron smelting furnace consisting of a natural gas electric turbine, which drives an electric generator. The hot turbine exhaust is directed around a refractory chamber (but not into) in order to provide some heat to the chamber. Power from the electric generator is directed to large induction coils built around the refractory chamber.
The refractory chamber is a vertical vase-like shape with an open top, with a port for supply of methane gas near the base, and below that a tap for continuous extraction of liquid iron. Some seed iron is maintained in the base, and preheated to the target temperature range with turbine exhaust gas and induction heating. Then a stream of methane is introduced into the chamber via the port. Then iron ore and flux pellets are poured into the top of the chamber.
The induction coils directly heat the metallic iron, and also heat the iron ore directly to a lesser extent. This, in combination with the exhaust heating, brings the ore to the target temperature causing the passing methane to strip away the oxygen and form more metallic iron. By periodically tapping the liquid iron out of the bottom of the chamber, and pouring new ore and flux into the top, this process can run continuously.
For the induction, The generator can output 60 Hz AC power continuously to provide service power to the facility, and the induction coils can be driven by a switched power supply which is fed by the generator.
The waste flue gas from the process is almost entirely carbon dioxide and water, with only small amounts of ash from impurities in the iron ore. This is a much cleaner and easier to control process for the processing of iron ore into pig iron than a traditional coal fueled blast furnace.
