Experimental research on microwave alkaline desulfurization of high sulfur coal slime

Aiming at the high-sulfur coal slime of Taiyuan Coal Preparation Plant, the method of microwave and KOH was used for desulfurization. The influence of microwave power, microwave irradiation time and KOH solution mass concentration on the effect of sulfur removal in coal slime was investigated and the reaction mechanism was preliminarily explored. The changes of inorganic mineral content, organic sulfur occurrence form and surface sulfur-containing functional groups before and after desulfurization were analyzed by XRD, XPS, FTIR tests. The results show that the optimum experimental conditions for obtaining the microwave desulfurization of coal slime in the KOH solution system are as follows: microwave power of 300 W, irradiation time of 4 min and KOH solution mass concentration of 300 g/L. Under this condition, the desulfurization rate is 40.8%. The pyrite and ash in the coal slime are significantly reduced, and the removal effect of organic sulfur is weak. The removal order (from easy to difficult) is as follows: sulfoxide, sulfone, thiol sulfide, thiophene. No new surface functional groups are generated in the sample, and the absorption peaks of sulfur functional groups are weakened to varying degrees. © 2022 Central South University of Technology. All rights reserved.