Fuels Furnaces and Refractories 9788120351578
The coal may have following minerals in varying quantities in addition to oxides of sodium and potassium i Shale or silt Hydrated silicates of aluminium ii Pyrite FeS 2 iii Gypsum CaSO 4 cdot 2H 2 O iv Lime stone CaCO 3 v Siderite FeCO 3 vi Magnesite MgCO 3 vii Apatite Ca 5 PO 4 3 F Cl OH Some of these minerals originate from the vegetal