MIGRATION OF ORGANIC SULFUR IN NANTONG AND LAIGANG COAL WITH ADDITION OF NaOH-H_2O_2 UNDER MICROWAVE TREATMENT

摘要

As two of the typical high-sulfur coking coal in China, Nantong coal (NTC) and Laigang coal (LGC) have been desulfurized by microwave/NaOH-H_2O_2 treatment. In this study, X-ray diffraction (XRD), Inductively coupled plasma (ICP) and Fourier transform infrared (FT-IR) have been carried out to unravel the migration of organic sulfur in coal, and the properties such as organic sulfur constituents and content of functional groups were analyzed. Microwaving at 1000 W for 10 minutes combined with NaOH-H_2O_2 (1:4 v/v) resulted in the highest organic sulfur desulfurization rate for NTC (22.3%) and LGC (31.75%) with a certain amount of organic sulfur transformed into iron sulfide, sulfate or sulfur-containing gas. Specifically, the results from FT-IR depicted a considerable decrease in three typical sulfur-bearing functional groups, whose retention proportion listed as: S=O > -S-H- > -S-S- in both two kinds of coal samples. Based on such findings, the transformation from organic sulfur to inorganic sulfur limited the growth of desulfurization rate , and S=O plays an significant role in the present desulfurization process, which takes a dominant responsible for the improvement of sulfur removal technology of organic sulfur.