Effectiveness of Limestone Usage and Optimization of Limestone Addition Ratio in Raw Material Production Industries that Use a Large Amount of Limestone

Abstract

Among the raw material production industries that use a large amount of limestone, the effectiveness of limestone usage in the steel production industry has been evaluated and the optimization of limestone addition ratio has been investigated. Based on the past research and development results concerning the CaO added basic sinter production technology, the phenomena of permeability deterioration caused by the excessive CaO addition and the actual operation tests, the multi-component calcium ferrites (SFCA) in sinter that have been currently intensively researched and developed have been evaluated. The reducibility of sinter in blast furnace has so far focused on the lumpy zone up to 1000 °C, but in the future research, it will be necessary focused on the reducibility and permeability in the cohesive zone up to 1000~1500 °C. The current chemical compositions of SFCA has the good reducibility and permeability in the cohesive zone, but the research and development are needed to maintain the appropriate range of CaO (CaO/SiO2 = 1.5~2.0) and further to improve the reducibility and permeability. The future progress of the research and development has been presented.