Abstract
The basic characteristics of Australian iron ore concentrate (Ore-A) and its effects on sinter properties during a high-limonite sintering process were studied using micro-sinter and sinter pot methods. The results show that the Ore-A exhibits good granulation properties, strong liquid flow capability, high bonding phase strength and crystal strength, but poor assimilability. With increasing Ore-A ratio, the tumbler index and the reduction index (RI) of the sinter first increase and then decrease, whereas the softening interval (ΔT) and the softening start temperature (T10%) of the sinter exhibit the opposite behavior; the reduction degradation index (RDI+3.15) of the sinter increases linearly, but the sinter yield exhibits no obvious effects. With increasing Ore-A ratio, the distribution and crystallization of the minerals are improved, the main bonding phase first changes from silico-ferrite of calcium and aluminum (SFCA) to kirschsteinite, silicate, and SFCA and then transforms to 2CaO·SiO2 and SFCA. Given the utilization of Ore-A and the improvement of the sinter properties, the Ore-A ratio in the high-limonite sintering process is suggested to be controlled at approximately 6wt%.
Highlights
Twenty-two large-scale blast furnaces (BFs) larger than 4000 m3 are currently operating in China
To clarify the high temperature behavior of Australian iron ore concentrate in the sintering process, four tests [3] including assimilability, liquid fluidity, bonding phase strength, and crystal strength [8] were carried out using the micro-sinter equipment
In the measurements of crystal strength, bonding phase strength, and liquid fluidity, the selected materials were Australian iron ore concentrate and a fine mixture of Australian iron ore concentrate and CaO pure reagent; the three selected materials were respectively pressed into a cylinder with a height of 5 mm and a diameter of 8 mm at 15 MPa for 2 min and sintered in the micro-sinter equipment
Summary
Twenty-two large-scale blast furnaces (BFs) larger than 4000 m3 are currently operating in China. With the rapid development of high-grade burden and large-scale BFs, sinter plays an increasingly important role in determining the operating conditions of BFs. the current status of the iron and steel market is weak; high production costs have become the main obstacle for the survival and development of steel enterprises [1,2,3]. Many researchers have focused on the sintering behavior of limonite and its effect on the properties of sinter Their results have indicated that limonite has a high crystal water (CW) content and that its use results in more pores after sintering, leading to a high sintering velocity and a long holding time at high temperatures, which in turn results in insufficient minerals crystallization [4,5,6].
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