EPR INVESTIGATION OF OXIDIZED ANTHRACITE

The influence of thermooxidative treatment at various temperatures on the paramagnetic properties of oxidized anthracite and the relation between the change of anthracite paramagnetism and formation of stable oxygen groups is investigated. It is established that the number of paramagnetic centers determined in initial and oxidized anthracite at 100 and 200-degrees-C is nearly equal. The quantity of paramagnetic centers for anthracite oxidized at 400-degrees-C is three times lower. The decrease of PMC concentration up to 400-degrees-C depends on the increase of the temperature, as well as on the oxidized process. The data obtained in vacuum show the same dependence decrease of PMC with enhancement of oxidation temperature as those obtained in air atmosphere. An increase of the g-factor with the increase of the oxygen adsorption has been found. A relation between the linewidth of the spectrum of anthracite and the extent of oxidation of anthracite has been established.