Importance of the textural characteristics of inert additives in the reduction of coal thermoplastic properties

Seven carbonaceous materials of different origin were chosen in order to study the influence of their porous structure on the modification of the thermoplastic properties of a bituminous coal. The materials included were: two non-coking coals, a petroleum coke, coke fines, two residues from tyre recycling and a bituminous residue. The materials were heat-treated to 900 °C to prevent any chemical interaction between the volatiles evolved during co-carbonization. The thermoplastic properties of blends that contained 10 wt.% of additive were measured by means of the Gieseler test. Microporosity was measured by CO2 adsorption at 273 K, whereas meso and macroporosity were determined by means of mercury porosimetry. The results of the porous structure assessment are discussed in relation to the modification of coal plasticity.