Study of the heat treatment effect of medium-temperature electrode pitch on carbonisate yield

Coal tar pitch is a residue of coal tar separation. It is widely used as a binder in the production of electrodes and anode mass. The production of pectic carbonisates and the development of methods to increase the value of its yield is of scientific and applied interest. The author conducted experiments on heat treatment in oxidising medium of medium-temperature electrode pitch of category BsTmelt = 71.5 °C (AO Altai-Koks, Russia). We conducted the process of heat treatment of the pitch in a 5.6 litre reactor heated by using an integrated electric heating system. To enhance the increase of Tmelt during heat treatment, we pumped the gas phase products from the reactor to a collection tank where they condensed. We performed heat treatment at T > 400 °C using both thermal oxidation of pitch and pumping of distillates. We formed the oxidising environment by supplying air by a compressor to the molten pitch. The air supply process started after the holding temperature was reached. The temperature controller provided the holding temperature. The author determined the yield of thermo-oxidation products, melting temperatures Tmelt, and volatile yields X for the resulting products. We obtained pitch with Tmelt = 140 °C and 158 °C. However, this heat treatment significantly reduced the yield of volatile substances in the final products. The temperature of carbonisation of heat-treated pitch was T = 650 °C and T = 850 °C. Therefore, research determines the carbonisate yields. Moreover, carbonisation proceeds with the additional holding times at 450 °C and 650 °C. Hence, heat treatment increased the carbonisate yield by 10%. Holding times at 450 °C and 650 °C also quantitatively increased the yield of carbonisate.