INVESTIGATION OF THE EFFECT OF ELECTRODE PITCH HEAT TREATMENT ON THE YIELD OF CARBONISATION PRODUCTS

The effect of preliminary heat treatment of medium-temperature electrode pitches on the yield of carbonisate is investigated. The objects of investigation were electrode pitches: B-grade pitch (Altai-Koks JSC, Zarinsk), B1-grade pitch (Evraz ZSMK JSC, Novokuznetsk). The pitches were treated by heating with further thermostating at 300 °C for different time intervals. For medium-temperature pitches, the dependences of the yields of heat treatment products, the yield of volatile substances, softening temperature on process duration were determined. It has been found that an increase in the softening point value proceeds at a higher rate in the case of B-grade pitch treatment than for B1-grade pitch, which may be due to a more intense decrease in the yield of volatiles for B-grade pitch in comparison with B1-grade pitch. It has been shown that after the heat treatment of the pitches, the content of α-fraction (the substances insoluble in toluene) in the final product increases by 46.8 % in the pitches of both grades. The dependence of carbonisate yield on the duration of the heat treatment of the pitch has been determined. It is found that preliminary heat treatment of pitch at 300 °C for 5 h allows an increase in the yield of carbonisate by 5 %. It is shown for the first time that the yield of carbonisate for B1-grade electrode pitch is higher than for B-grade electrode pitch, which correlates with the higher content of α1-fraction (the substances insoluble in quinoline) in the former. This dependence is also retained for heat treated pitches. For the first time, the dependence of the yield of volatile substances in carbonisates on the duration of heat treatment of pitches was established.