Geochemical characteristics of Galandrud coal in central Alborz, Iran

This study focuses on the geochemistry of trace elements and parameters of coal quality of bituminous coal belonging to the upper Triassic-lower Jurassic era, collected from the Galandrud region in Central Alborz, northern Iran. Galandrud coal on an air-dried basis are characterized by broad variation in the amount of ash (ranging from 6.4% to 12.73%), a high content of volatile matter (33.32–37.45%) and high gross calorific values (7430–8880 kcal/kg). The mineral matter of the coal samples studied is made up of dolomite (>90%), quartz, sphalerite, galena, pyrite and clay minerals. Major elements are positively correlated with ash content suggesting an association with inorganic constituents. Based on statistical analyses, concentrations of trace elements such as Co (51.3 × 10−6–152.9 × 10−6), Ba (368 × 10−6–3297.4 × 10−6), Cr (65.5 × 10−6–194.2 × 10−6), Mo (5.6 × 10−6–18.2 × 10−6), Ni (72.9 × 10−6–152.9 × 10−6) and V (245.5 × 10−6–520 × 10−6) are higher than world coal averages. However, low concentration of some volatile elements such as As, Hg and U are present in low concentrations of the various types of coal studied.