Effect of Random Pore Shape, Arrangement and Non-adhesion Grain Boundaries on Coke Strength

• Published in: ISIJ International 2014/11/15, Vol.54(11), pp.2519-2526
• Main Authors: Saito, Yasuhiro, Matsuo, Shohei, Kanai, Tetsuya, Toishi, Ayuko, Uchida, Ataru, Yamazaki, Yoshiaki, Matsushita, Yohsuke, Aoki, Hideyuki, Nomura, Seiji, Hayashizaki, Hideyuki, Miyashita, Shigeto
• Format: Article
• Language: English
• Subjects: coke; coke strength; ironmaking; low-quality coal; non-adhesion grain boundary; RBSM
• ISSN: 0915-1559; 1347-5460
• DOI: 10.2355/isijinternational.54.2519

In this study, the rigid bodies-spring model (RBSM) was used to numerically investigate how the fracture behavior of coke is affected by pore structure and non-adhesion grain boundaries. To study the effects of pore structure, randomly shaped pores were generated and randomly positioned in a coke matrix. The random shapes of pores were controlled by pore roundness and their random sizes were controlled by equivalent circle diameters. Non-adhesion grain boundaries were also randomly located in the coke matrix. First, results for a coke model with realistic pore structures showed that large distorted pores decrease coke strength. Second, fracture behavior was analyzed for a coke model composed of a coke matrix, pores, and non-adhesion grain boundaries. Coke strength decreased as the number of non-adhesion grain boundaries increased; these numerical results agreed with previous experimental data. Further, coke strength decreased even in the presence of only a relatively small number of non-adhesion grain boundaries. This is because, when non-adhesion grain boundaries occur in stress-concentrated regions, those boundaries become origins for fracture. This indicates that the presence of non-adhesion grain boundaries is one factor that decreases the strength of coke when it has been blended with low-quality coal.