The
HIsmelt Process has its origins in the early1980's when Rio Tinto Limited identified the
potential to adapt the high scrap rate steelmaking and iron bath coal gasification processes
developed by Klockner Werke to the direct smelting of iron ore. Development of the HIsmelt
Process commenced with a 60 tonne K-OBM converter. After successfully proving the concept, a
small scale pilot plant was constructed and operated at Maxhutte Works in Germany. The plant
design was based on an enclosed horizontal vessel to overcome process containment issues
experienced in the 60 tonne converter trials.Whilst the process scale-up was successfully demonstrated, the complexity of the engineering,
poor plant availability and difficult operational requirements brought into question the commercial
viability of the plant design. After three years of operation the plant was substantially reconfigured
to address these issues. The horizontal Smelt Reduction Vessel (SRV) was replaced with a
vertical vessel. This allowed extensive use of water cooled elements in the process top space to
address availability issues. Injection of solids was through water cooled top injection lances as
opposed to submerged tuyeres thereby simplifying the engineering and overcoming operational
issues encountered with the submerged bottom tuyere used in the horizontal vessel. Installation of
the vertical vessel proved successful.
The plant achieved very high plant availability whilst still maintaining high process performance
despite the increased vessel heat losses due to the added water cooling.
