7TH EUROPEAN COKE AND IRONMAKING CONGRESS - ECIC 2016

Metallurgical coke samples were retrieved from the tuyere drilling of an operating blast furnace. These were analysed using a novel fractographic approach to identify and quantify the various coke failure mechanisms. This allowed for quantification of the factors contributing to the strength of the coke through analysis of coke fracture faces. Tuyere level cokes were found to display different failure mechanisms compared to the feed coke, implying an influence of the blast furnace reaction environment. Feed coke breakage behaviour was strongly influenced by existing fissures, while the breakage of the deadman coke lumps was dominated by pore wall collapse through intergranular crack growth as well as erosive wear. This fractographic study demonstrates that despite the inherent heterogeneity of coke, the fracture faces generated by the evolution of the external fissures in the large coke lumps show evidence of several failure mechanisms, in addition to the erosive wear resulting from the blast furnace exposure. The main factors contributing to coke strength from our fractographic analysis were quantified using a standard scale and summarized using a radar diagram. Understanding the differences in the microstructural weaknesses/fracture properties of the coke may have implications for the selection of coal blends and processing during cokemaking that would result in improved coke performance in the blast furnace.