Experimental research on the spontaneous combustion of Yangquan coal induced by electrochemical oxidation of pyrite

Abstract

Abstract The 15# coal seam of Yangmei No.5 Mine, which produces anthracite, which is the least prone to spontaneous combustion, has a serious hidden danger of spontaneous combustion due to the high sulfur content in the coal. Based on the better conductivity of anthracite, we designed an electrolysis experiment to accelerate the electrochemical oxidation of pyrite in coal. Through experiments and analysis of thermodynamic characteristic parameters, it is obtained that the electrochemical oxidation of pyrite and its main products Fe3+ and Fe2+ have a coupled catalytic effect on the spontaneous combustion of high-sulfur coal in Yangquan. Combined with the FTIR test and analysis, it is found that the electrochemical process causes spatial polarization in the coal, so that polar groups such as –OH undergo spatial diversion and increase the activity. Due to the high content of –OH in Yangquan anthracite, the electrochemical process has the greatest effect on promoting –OH oxidation. Fe3+ and Fe2+ act as strong oxidants and free radicals to promote the –CH2– reaction to generate C=O and promote the generation of CO. This research provides a new direction for the exploration of the spontaneous combustion mechanism of high-sulfur anthracite.