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.
Highlights
The 15# coal seam of Yangmei No.[5]
This shows that the bacterial oxidation form of pyrite has less and slower impact on coal spontaneous combustion
Wu et al.[10,11,12] believed that pyrite can react electrochemically with the contact surface of water and humid environment, and the potential difference, electrolyte and oxidant and electron channels are the basic conditions for electrochemical oxidation of pyrite. Kelsall[13] believes that the electrochemical oxidation of pyrite is a complicated series and parallel reaction step, but the reaction eventually produces Fe2+/Fe3+ and S/S2O32−/SO42−. Tu14,15 found that in a humid environment, the main oxidation equation for electrochemical reaction of pyrite is: positive electrodes: FeS2 + 8H2O = Fe2+ + 2e− + 2SO24− + 16H+ + 14e− negative electrode: O2 + 4H+ + 4e− = 2H2O, Fe3+ + e− = Fe2+
Summary
Under a specific atmosphere (gas atmosphere is 50 ml/min air flow, weight loss heating rate 10 °C/min, test temperature range is 25–700 °C), the thermal weight loss behavior of coal samples is analyzed using the German Netzsch STA449F3 instrument. The experimental procedure is as follows: 100 g coal sample dried in a vacuum at 110 °C for 24 h is placed in an adiabatic oxidation bottle in an adiabatic furnace, and the bottle cap is tightly fastened. The gas is collected regularly at the exhaust port of the oxidation bottle, and the CO content produced during the low-temperature oxidation of coal is analyzed by a meteorological chromatograph. Grind the coal sample with a mortar to a size of 250 mesh or more, and vacuum-dry it at a constant temperature of 110 °C for 4 h to remove moisture from the coal. After cooling to room temperature, the coal and KBr are fully mixed in proportion and pressed into tablets
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
