A new physical process for desulfurization of low-rank coals

A processing route involving low temperature carbonization followed by dry magnetic separation is put forward for the desulfurization and deashing of typical low-rank lignitic coals. The -3 mm lignite samples were subjected t o low temperature carbonization at 600 degrees C for 15 min and then upgrad ed by magnetic separation. Under optimum conditions, a remarkable decrease in both ash and more importantly in total and particularly organic sulfur w as achieved. A systematic study of the mechanism of the sulfur removal toge ther with the literature findings reveals the formation of an iron-sulfur c oordination compound in coal. (C) 2000 Elsevier Science Ltd. All rights res erved.