Abstract
Acid treatment changes the evolution of coal microstructure, and exploring the internal relationship between different acid treatment and coal oxidation is of great significance for the prevention of coal spontaneous combustion. In this paper, lignite collected from Ximeng mine was treated with hydrochloric acid and nitric acid. The oxidation performance and microstructure parameters of treated coal were analyzed by gas chromatograph, mercury intrusion, FTIR and XPS. According to test results, low-temperature (T < 200 °C) oxidation process of coal involves the slow oxidation and rapid oxidation stages owing to different apparent activation energy. HCl and HNO3 treatment improved the pore volume and porosity, and enhanced the oxygen adsorption capacity, thus both accelerating oxidation reaction of coal during slow oxidation stage with temperature below 100 °C. However, in the rapid oxidation stage above 100 °C, HCl treatment inhibited oxygen reaction because the number of oxygen-containing groups including ether and carbonyl band reduced and the hydrogen bonding force for strengthening the stability of coal molecular enhanced. Whereas HNO3 treatment exerted promoting effect on coal oxidation for its pre-oxidation effect and the decrease of coal molecular stability. Further, the conversion mechanism of main active functional groups in acid-treated coal was proposed.
Sign-in/Register to access full text options 
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
