The properties of a suite of experimental cokes made from Australian coals were studied. Image analysis was used to quantify the coke pore and pore wall microstructure, while ultra-micro indentation characterised the strength of the coke wall textures. The micro-properties were compared with compact tension measurements of bulk coke strength. The microstructural features of good cokes included a relatively thick coke wall, and a pore size distribution that has small mean pore size combined with a high pore density. It was found that inert maceral derived coke microtextures displayed the highest hardness values. The hardness of reactive maceral derived coke was lower and decreased with increasing mosaic size. For the set of cokes studied, the hardness and modulus were comparable for the same coke microtexture, irrespective of the coal source. Fracture toughness could not be determined for the coarser mosaic textures using the crack measurement approach. For those textures where measurements were possible, fracture toughness for the components was found to be independent of the parent coal.

Pilot scale coke ovens are widely used to produce coke samples for characterisation and also to assess the coking behaviour of coal blends. The Newcastle Technology Centre of BHP Billiton has built a sophisticated 400 kg oven, which can produce cokes under a range of carefully controlled bulk densities and heating rates. A freely movable heating wall allows the thrust generated at this wall at the different stages of coking oven to be determined. This paper describes comparative work carried out to determine a laboratory stabilisation technique for laboratory cokes. The strength of stabilised cokes are characterised using a number of tumble tests, and correlations between different drum sizes are also given since a major constraint in laboratory testing is the limitation in the mass of sample available. Typical oven wall pressure results, and results obtained from embedded temperature and pressure probes in the charge during coking, are also presented.