A Novel Micro-CT Technique for Characterising Structural Interfaces in Metallurgical Coke

The quality of interface bonding between inert maceral derived components (IMDC) and reactive maceral derived components (RMDC) in coke made from a variety of coal blends was quantified based on micro-CT images. A novel micro-CT image processing algorithm was developed to identify the boundary of IMDC and to determine the porosity profiles in the vicinity of IMDC surface. The bonding quality was assessed using excess porosity which is the difference between the peak and averaged porosity around IMDC surface. High excess porosity values indicate poor RMDC-IMDC bonding, while low or even negative excess porosity values indicate good quality bonding. Poor bonding with IMDC only occurs with one type of RMDC from a low- volatile matter high-rank parent coal. Further examination into this RMDC series indicates dependence of the excess porosity on the internal IMDC particle porosity at low IMDC phase density, combined with a lack of fusible material near the surface of the IMDC. The fusible material improves bonding, while low porosity near the IMDC inhibits bonding.