CHEMICAL DESULFURIZATION OF COAL WITH HYDROIODIC ACID

A novel method for the chemical desulfurization of coal in relatively moderate conditions and short times is presented. Using concentrated h ydroiodic acid as a desulfurizing agent and microwaves as the energy s ource, sulfate and pyritic sulfur are completely removed in 10 min. Mo reover, for the low-rank coals studied, variable amounts of organic su lfur, up to 70% in 20 min, can be removed, for a total sulfur (organic + pyritic) elimination greater than 80%. The study of the process sho ws that time and temperature of the reaction are the main factors affe cting the desulfurization process. Experiments with other acids and lo wer concentrations showed low yields, the special characteristics of t he concentrated hydroiodic acid being the driving force of the reactio n. Experiments carried out at different microwave power did not show a ny singular effect of the microwave irradiation on the removal of sulf ur.