论文部分内容阅读
Most of the research published on the effect of alumina on iron ore sintering is based on work with Indian or African ores.These ores tend to contain alumina in the mineralogical form of gibbsite.Most Australian iron ores contain alumina in the form of kaolinite or aluminous goethite.Pilot-scale sintering studies reported here found that when Brockman – Marra Mamba fines from BHP Billiton containing kaolinite and aluminous goethite were added to the blend,sinter quality(strength,size,RDI,RI)could be maintained with small increases in the coke addition as alumina was increased from 1.7%to 2.3%.As alumina level swere further increased to 2.7%,which is significantly higher than most sinter plant operations,productivity could be maintained but sinter strength decreased.Even at these high alumina levels the low temperature reduction degradation of the sinter did not deteriorate.This is very different to what has been reported for ores with gibbsite alumina.Optical microscopy and SEM EPMA investigations found that for the higher alumina cases the extra fuel and higher sintering temperatures led to more replacement of hematite by magnetite and SFCA phases in the sinter.Also the alumina concentrated more into these phases.This resulted in a sinter composition and morphology that maintained its resistance to reduction degradation.Newer techniques such as X-ray micro-tomography are being applied to investigate the 3D internal structure of the sinter and its effect on quality.This forms part of future work that is required to further improve understanding of the influence of alumina type(especially aluminous goethite)and help optimize sintering with Australian iron ores.