Rate of oxidation of graphite in carbon dioxide

Experimental data are presented on the rate of oxidation of electrode graphite spheres (18 in. to 78 in. dia.), blocks and sized granules (8 to 30 mesh) in carbon dioxide-argon mixtures at one atmosphere total pressure and in carbon dioxide at pressures up to 40 atm. The effects of size, pressure and temperature on the extent of internal burning are demonstrated. It is found that internal burning occurs throughout and that the rate is controlled by the chemical reaction of gas and carbon at one atm CO2 for spheres less than 0.2, 0.3 or 0.6 cm dia. for 1100, 1000 and 900° respectively. For larger spheres or at higher pressure or temperature, internal burning occurs only in a zone near the surface—that is, pore diffusion is incomplete.