HIsmelt process

The core of the HIsmelt technology is the Smelt Reduction Vessel (SRV), which replaces the function of a blast furnace.

Iron ore fines are injected deep into the bath where they are reduced instantly on contact with carbon dissolved in the bath. This reaction produces iron (Fe) and carbon monoxide (CO).

Coal is also injected into the bath, where it is absorbed in the metal to replenish the carbon used in the reduction reaction.

Reaction gas (CO) and coal gasification products are generated from deep within the bath and form a fountain of mostly slag and some metal.

Hot air at 1200°C, which is enriched with oxygen, efficiently combusts the gases generated within the bath - releasing large amounts of energy.

Combustion energy is carried back to the bath via the fountain of slag and metal.

The role of the SRV and a basic flowsheet for a HIsmelt plant are explained in more detail below:

The primary product from the HIsmelt process is hot metal. Liquid iron is tapped continuously through an open forehearth and is free of slag.

Secondary products from the SRV are slag and offgas. Slag is formed from the impurities in the iron ore (gangue) and coal (ash), which are fluxed using lime and dolomite. Slag from the HIsmelt process can be utilised as a raw material in a variety of applications in the construction and agricultural industries. Offgas from the process has energy value and is cleaned, cooled and used as a fuel and for power generation.