Cleaning of Thar Coal by Froth Flotation and Water Washing

The demand for a constant supply of energy is increasing day by day. To meet these increasing demands, natural resources must be utilized smartly. Pakistan having 185 billion tons of coal have huge potential of energy and chemical production from it. However, 175 billion tons of it, found in Thar region of Sindh province, need pre-cleaning of coal in terms of sulfur and ash removal before its effective utilization. In this work, cleaning of Thar coal was carried out using froth flotation and water washing techniques. Three different particle sizes (250 sum, 149 sum, and 105 sum) were employed to study the effect of froth flotation on ash and sulfur reduction. Experiments were carried out in laboratory flotation cell under different set of conditions (i.e., flotation with and without collector and frother and by simple water washing). Kerosene oil was used as a collector and pine oil as a frother. Characterization of raw and treated Thar coal samples was carried out by ASTM standards. The results exhibited an inverse relationship of particle size towards efficiency of the cleaning process; thus, the optimal combustible recovery was attained at 105 sum particle size. Furthermore, FTIR results disclosed the presence of aromatic and aliphatic structure in treated coal samples. Thermo-gravimetric analysis was also performed to determine the weight loss in raw and treated samples and increased combustion efficiency and reactivity was observed in treated coal samples.