INFLUENCE OF NATURAL WEATHERING OF 2 MEDI UM-VOLATILE BITUMINOUS COALS OF SIMILAR RANK ON COKE QUALITY

The study of the weathering of two bituminous coals stored at the INCA R stockyard and its influence on coke quality is presented. These coal s of similar rank are present in industrial blends used by the Corpora cion Siderurgica Integral (CSI) for the production of blast-furnace co ke. Of all the techniques used to determine the degree of weathering, via thermoplastic properties, Gieseler plastometry was found to be the most sensitive. Coking tests were carried out in the semi-industrial coking plant at INCAR, The effect of weathering on each coal series is completely different. Weathering produces a loss of maximum fluidity accompanied by a decrease in aliphatic hydrogen in both coals. However , the loss rate is different in each case. Coke quality clearly decrea ses in one, while in the other improves at first but then gradually de teriorates. An improvement in coke quality due to weathering not only affects some high-volatile coals as it is well known but also medium-v olatile coals.