Multi-elemental analysis of Indian coals and its gravity fraction based on ICP-OES

Inorganic elements in coal are often regarded as a nuisance being responsible for most of the problems arising during coal utilization. Commonly found group of minerals in coal are major (quartz, pyrite, clays, and carbonates), minor and rare earth elements. Three Indian coals were subjected to gravity fractionation to study the association of major, minor, and rare earth elements. It showed that concentration of elements like Al, Ca, and Fe is much lesser in lighter gravity fraction than the heavier gravity fraction. Elements like Fe and Mn were higher at 1.50 gravity fractions with respect to its nearby gravity, while Co content was little higher in lighter fraction. Major toxic elements such as As, Pb, and Cr can be reduced by almost 3–4 times by washing coal. The rare earth elements Y, Lu, Ce, Dy, and La are embedded with mineral matter of the coal. Gravity fractionations, distributing the ash content, and elements link with organic materials. This study showed that along with coal beneficiation, separation of valuable elements in different gravity fractions to be monitored so that the coal beneficiation could be a win-win strategy for upgradation of coal quality and pave the route for extraction of economically important elements