Weathering study of an industrial coal blend used in cokemaking

Weathering studies were carried out on a coking coal blend prepared and gro und at industrial scale and stored in the open yard. This typical and compl ex blend, composed of 13 different coals was used by the Spanish Steel Comp any. Several methods were applied for detecting weathering in the blend. Gi eseler maximum fluidity was the most sensitive indicator of the loss of the rmoplastic properties. Carbonization tests were carried out in a movable-wa ll oven and a semi-industrial oven of 6 t capacity. In addition to the meas urements of internal gas pressure and coking pressure, laboratory tests wer e performed to measure expansion/contraction behaviour of the coal blend. A clear decrease in internal gas pressure with weathering was observed in th e semi-industrial oven. As regards coke quality, no significant changes wer e produced in a storage period of ten months, however after this date impai rment was observed.