Manufacture of high density carbon blocks by self-sintering coke produced via a two-stage heat treatment of coal tar.

High-strength and high-density carbonized carbon blocks from self-sintering coke were manufactured using coal tar and two-stage heat treatments (1 and 2 stage treatments). First, the molecular weight distribution of the refined coal tar was controlled through a pressured heat treatment (1 stage treatment). Second, the 1 stage heat-treated coal tar (1S-CT) was treated using a delayed coking system (2 stage treatment) to become the self-sintering coke. Finally, carbon blocks were molded from 2 stage heat-treated coke (2S-C) and carbonized at 1200 °C for 1 h. Through rapid decomposition of the high molecular weight components in the coal tar at 360 °C in the 1 stage treatment, the molecular weight distribution of coal tar was confirmed to be controllable by the 1 stage treatment. Swelling during carbonization was observed in carbon blocks manufactured from 2S-C containing more than 15 wt% of volatile matter from 150-450 °C. The optimum conditions of the two-stage heat treatments were confirmed to be 300 °C for 3 h and 500 °C for 1 h. The highest density and flexural strength of the carbonized carbon blocks manufactured from 2S-C were 1.46 g/cm and 69.2 MPa, respectively.