Treating bituminous coal with ionic liquids to inhibit coalspontaneous combustion

Coal spontaneous combustion (CSC) is an extremely complex physical and chemical reaction between coal and oxygen, and it results in the gradual accumulation of thermal energy that eventually produces conditions that are favorable for combustion. Ionic liquids (ILs) inhibit coal oxidation and reduce the amount of heat that is produced. A synchronous thermal analyzer was used to examine the effects of imidazolium-based ILs on bituminous coal from two sources. The results revealed that with the anion [BF4](-), the inhibiting effect of [BMIM](+) was stronger than that of [EMIM](+). Moreover, with the cation [BMIM](+), the inhibiting effects of [BF4](-) were stronger than that of [I](-) and [NO3](-). The inhibiting effects of the ILs on CSC were estimated using the Ozawa-Flynn-Wall method, which relates the apparent activation energy to the degree of conversion. The inhibiting effect of [BMIM][BF4] offers a basis for effectively preventing CSC and is favorable for universal application.