LEACHING OF MINERALS IN SUBBITUMINOUS INDIAN COAL AND CHARACTERISATION OF THE PRODUCTS BY SEM

摘要

Coal is chemically and physically a complex and heterogeneous material, consisting of organic and inorganic mineral constituents. Presence of minerals in excess will pollute water, air and soil. Concerted efforts are needed to reduce 'ash forming' inorganic elements and to develop clean methods of using coal. This paper reports the demineralization of sub bituminous coal with EDTA, HCl, HF, chloroform and acid mixture. The residual coal from each treatment was analyzed using Scanning Electron Microscopy (SEM) and Ultimate analysis. All the micrographs were bright field and revealed several features corresponding to the mineral grains. It comprised of lithophiles like aluminium, silicates and calcium. The absences of some morphological features correspond to inorganic elements in residual coal samples confirming 'demineralization'. This result was further confirmed with the CHNS analysis. It was evident from the results that amongst the leachants used. Hydrofluoric acid and acid mixture had significant effect in removing the mineral matter, sulphur and oxygenated functional groups.