An ESR study of the adsorption of oxygen and nitric oxide on the fusain and vitrain fractions of anthracite coals

Origin of electron paramagnetic resonance signal in anthracite

“…Most of the previously reported studies of anthracite powders were performed on a material which was powdered and subjected to demineralization [14,[17][18][19][20][21]. After mixing with diamagnetic powder, the samples so prepared were subjected to dynamic vacuum for a period not shorter than 24 h in the measuring tube and sealed.…”

“…For this reason, EPR is used mostly for distinguishing between various types of anthracite or for distinguishing anthracite from coal [16]. More detailed studies were performed of anthracite undergoing various treatments [14,[17][18][19]. In the case of highly metamorphosed Bulgarian anthracite, the signal from the powdered sample was shown to be a two-component one, and both components were of Lorentzian shape.…”