INFLUENCE OF ALUMINA COMPONENT ON MELT FO RMATION IN SINTERING PROCESS AND SINTER QUALITY IMPROVING TECHNOLOGY

The bad influence of the Al2O3 component in sinter on the product yiel d and the sinter quality has already been verified through the experie nce acquired in the actual operation. It is also reported that much re search has been conducted on a technology for minimizing this bad infl uence of the Al2O3 component in sinter. A method to suppress the bad i nfluence of the Al2O3 component on the product yield and the sinter qu ality was examined. The purpose of this method was to form a crystal e mbedding Al2O3 component in a silicate slag phase, while preventing a rise in the melting point due to the Al2O3 component. The adoption of a method which mixes FeO raw material at a high rate in combination wi th the use of limestone coarser than that previously used has raised t he product yield and improved the sinter quality as well. Further, wit h this method, a eutectic microstructure made up of ''Magnetite + Fine calcium ferrite + Silicate slag'' has been increased in sinter. The A l2O3 content in the eutectic microstructure is more than twice the ave rage content of Al2O3 of the entire sinter. This condition is such tha t the Al2O3 component has been embedded in this eutectic microstructur e. The increase in this eutectic microstructure of sinter has resulted in the improvement in the product yield and low-temperature reduction degradation index (RDI) of sinter.