The AusIron® process is a bath smelting process which directly processes ferrous bearing feed materials to produce molten iron.

The process takes place within a smelter vessel, equipped with multiple lances. Each lance burns coal with oxygen-enriched air at the lance tip, which is submerged in the smelter slag bath. The lance tip combustion conditions are controlled to prevent bath oxidation, and optimised for maximum energy release to the bath.

Reductant coal, ferrous feed and fluxes are fed by gravity to the smelter slag bath through ports in the furnace roof. Ferrous materials rapidly dissolve in the slag bath, whilst the reductant coal reacts with iron oxides contained in the slag. The turbulence generated by submerged combustion provides efficient mixing, resulting in high smelting rates.

Carbon monoxide produced by smelting reactions, together with reductant coal volatiles and residual fuel from lance tip combustion, is post-combusted immediately above the slag bath using oxygen-enriched air delivered through a shroud around each lance. The evolution of gases from the lance tip generates a cascade of slag droplets above the bath providing a large surface area for efficient recovery of post-combustion energy to the slag bath.

Complete combustion of fuel gases is achieved within the furnace maximising energy recovery and avoiding the production of difficult low CV fuel gases.

Offgases leave the furnace through a boiler tube offtake that forms part of the directly-coupled energy recovery system.

Hot metal product and slag are tapped independently from the furnace hearth.

The furnace hearth is refractory lined in the metal bath region. The sidewalls and roof are water-cooled to withstand the intense operation and turbulent slag. The water-cooled furnace sections are slag coated during operation reducing heat losses and protecting cooling elements from damage.

Furnace operations can be stopped quickly, and the process idled for long periods by submerged combustion of fuel coal only. For shutdown the furnace can be drained of its contents and the lance tip combustion used to maintain furnace temperature. Operations can be quickly re-established by feeding solid slag, which is melted using the lances. Once a molten pool is established, the lances can be submerged, and smelting operations resumed.