Petrographic controls on phosphorous distribution in coal seams of the Jharia basin, India

In recent years, the international coking coal market is experiencing an acute shortage of coal supply which has caused a fluctuation in its price. Degradation of coke, in the blast furnace, is largely controlled by its inherent mineral matter. Phosphorous occurs in all coals in minor or trace amounts and is an important parameter to coal users, particularly in steel industries. The mode of occurrence and distribution of phosphorous minerals in 17 coal samples of the Jharia coal basin were investigated through petrographic examinations, technological characterisation and phosphorous distribution. The results reveal that the dull bands are eight times more enriched in phosphorous than the bright bands. The macerals of the inertinite group and mineral matter positively correlate with the phosphorous content, whereas vitrinite macerals have an apathetic correlation. The impact of the thermal alterations is localised and diminishes away from the contact of the intrusion. In contrast, the faulting does not appear to have any effect on the phosphorous content.