Proceedings of iCMEMS Conference 2017

The strength and behaviour of coke at high temperatures has a huge impact on its performance in the ironmaking process. Prior studies reporting the effect of temperature on the failure stresses of cokeshave not always shown consistent trends owing to differences in sample sizes, properties, and testing methods. In the present work, a high-CSR Australian coke was subjected to high-temperature mechanical tests using a unique high-temperature test facility at ANSTO to determine its compression strengths and the associated microstructural and mineralogical modifications. X-ray diffraction analysis and micro-CT analysis were used to determine the mineralogical and microstructural changes in the cokes after testing. The work showed that there were three regimes of deformation in the coke with increasing temperature. Furthermore, the work showed that compression strengths of the cokewere higher at elevated temperatures in comparison to the observed values at room temperature. Microstructural analysis showed an increase in the extent of porosity after high-temperature testing owing to the in situ reduction of ash species in the coke. With increase in temperature, it is expected that glassy phases formed by ash fusion as well as increased graphitisation assist in enhancing plastic flow, which contributes to an increase in strength of the coke samples at these temperatures. However,with increasing graphitisation extents, the load-bearing capacity would decrease, leading to a lowering of the maximal strengths at the top temperatures. The findings provide an improved understanding ofthe mechanisms affecting high-temperature strength development in cokes and can further assist in correlations the strengths with variations in coke and parent coal characteristics