Demineralization and desulfurization of subbituminous coal with hydrogen peroxide

The effect of hydrogen peroxide solution alone and in the presence of dilut e sulfuric acid on desulfurization and demineralization of coal collected f rom the Makum coalfield situated at North-Eastern region, India, was invest igated and the process conditions (temperature, time, and hydrogen peroxide and sulfuric acid concentrations) were optimized. Hydrogen peroxide (15%) alone leads to removal of over 76% pyritic sulfur and 70% sulfate sulfur an d around 5% organic sulfur and 14% ash at 25 degreesC, which increases to a lmost complete removal of pyritic and sulfate sulfur and over 26% organic s ulfur and 43% ash in the presence of 0.1 N H2SO4. The oxidation rate was fo und to increase significantly with increasing temperature (15 to 40 degrees C) and hydrogen peroxide concentration (2.5 to 15%). The rate of reaction w as found to be well represented by a continuous reaction model that was sec ond order with respect to pyritic sulfur. The activation energy for pyritic conversion in Boragolai and Ledo coal are, respectively, 19.33 x 10(6) J k mol(-1) and 39.72 x 10(6) J kmol(-1).