DIRECT EVIDENCE THAT THE THERMOPLASTIC PROPERTIES OF BLENDS ARE MODIFIED BY INTERACTIONS BETWEEN THE COMPONENT COALS

A number of Australian coking coals were blended and their behaviour d uring carbonization was examined using proton magnetic resonance therm al analysis (PMRTA) to measure the degree to which the fusion behaviou r of blends was affected by interactions between the component coals. Most blends examined showed evidence of interactions. Both significant positive and negative interactions (degree of fusion of the blend res pectively greater and less than expected if the coals had acted indepe ndently) were observed. When interactions occurred between two coals, the temperature at which the interaction was greatest was independent of the proportion of the coal components in the blend, but the magnitu de of the interaction was found to be proportional to x(1-x), where x is the proportion of one component in the blend. The interaction betwe en coals is suggested to be mediated by interchange of volatile materi al. (C) 1997 Elsevier Science Ltd.