A perspective of goethitic ore sintering fundamentals

The main purpose of iron ore sintering is to produce a strong agglomerate for the blast furnace. This is achieved by partially melting a sinter mix at high temperature and then allowing the melt to solidify into a bonding phase for the unreacted material. The melt formation and subsequent solidification processes are highly dependent on the composition of the blended mix. This paper summarises the differences in sintering behaviour between hematite ores and goethitic ores based on past research programs carried out at BHP Billiton. From a fundamental evaluation of the sintering process, it is clear that productivity can be an issue with goethitic ores because of their low bulk density and high porosity. This paper recommends steps towards overcoming losses in productivity. The effect of goethitic ores on coke rates is also a matter of general concern and this study shows that the addition energy required to dehydrate goethites and remove the additional water introduced into the system is comparatively small. The properties of melts have been shown to be particularly important in determining yield from a sinter machine and it is evident that the easy-melting properties of goethitic ores will also have an impact on this area. This paper also reviews our current understanding of how goethitic ores can influence sinter quality. The implication of fundamental knowledge on practical sinter plant operation is discussed throughout and collated at the end of the paper.