Abstract
Several deashing pretreatment procedures at room temperature were examined against some non-fusible coals of low rank to improve their cocarboni-zation susceptibility with A240 for the better fusibility and anisotropic development. The immersion in 1N-HCl containing methanol or in aqueous EDTA-2Na (EDTA-2Na/Coal=7/100 by weight) for 24h was found very effective to improve the fusibility for better adhesion and to increase the anisotropic region as well as the size of anisotropic unit developed from the coals. The same treatment for 1h was effective to a less extent, being much superior to the treatment in boiling water for 24h.
The minerals of calcium, magnesium and iron in the coals were markedly removed by 1N-HCl at room temperature, the amount of removed calcium being comparabe to that by 1N-HCl at 100°C, although the effect of the former pretreatment was inferior to that of the latter.
Relationship between the extent of deashing and the anisotropic development of a coal was studied to resolve how the deashing influences the enlargement of anisotropic region and size of anisotropic unit, respectively in the cocarbonization process. The cocarbonization susceptibility was discussed from the mechanistic view point.
