Degree Name

Doctor of Philosophy


Department of Materials Engineering


Fundamental pore formation mechanisms in iron ore sinter and pellets were investigated. The study was first conducted with tablets made from iron ore and limestone particles, with and without addition of coke, and the results were then tested and proved in real pellets made with a laboratory ball mill and in real sinter made with a sintering pot. It was found that pores were formed at sites of limestone and coke particles and that a number of factors had a significant influence on the pore formation and the final pore structure, such as limestone particle size, coke particle size, iron ore particle size, amount of limestone, temperature and initial porosity, etc. It was also found that the air flow through the sintering bed was very unlikely to cause any pores to form in sinter. Different types of pores were classified in terms of their origins. The results have shown that an open or close to open pore structure may be achieved by controlling the temperature and using proper amounts and particle sizes of limestone, coke and probably other additives. The results have also shown that porosity and limestone particle size had a strong effect on reducibility and it might be possible to achieve high reducibility and high strength simultaneously with an open or close to open pore structure at low porosity. The results of the present work are useful in understanding the iron ore sintering and pelletizing processes and in improving the quality.