Demineralization of a Low-Rank Coal to Produce Clean Coal for Industrial Utilization

An investigation was carried out for the demineralization of a low-rank coal containing high ash (37.74%) and sulphur (8.65%) content to clean it for industrial utilization. The raw coal was evaluated by proximate analysis, total sulphur and Gross Calorific Value (GCV). Run-of-mine coal as received was stage crushed and ground under controlled conditions to fair liberation size. The gravity concentration technology using diagonal deck concentrating table was employed to produce clean coal. A number of gravity separation tests were carried out by varying different parameters i.e. feed size, feed rate, wash water flow rate and deck inclination angle. The final de-mineralized clean coal obtained at optimum conditions contained 13.04% ash and 2.61% sulphur and found suitable for many industrial applications.