Dissanayake Mudiyanselage, Nethma Thejani Dissanayake

Petroleum coke (petcoke) is a waste by-product of the upgrading process in the oil refining industry. It has limited utility in other areas of application.1 High carbon content (over 85 wt.%), low ash content, and softness make petcoke a potentially valuable precursor for graphitization, where amorphous carbon can be transformed into graphitic carbon. The synthetic production of graphite is gaining more interest due to the increasing demand for battery materials.2,3 Without metal moderators, achieving graphitization requires significantly high temperatures (> 2500 °C). Magnesium (Mg) has been identified as a promising reactant because of its efficacy in promoting graphitization and its relatively simple removal from the final product.3–5 The optimized conditions of magnesium-assisted graphitization showed an electrical conductivity of (3552.0 ± 78.5) S/m at 10 mA. Furthermore, bimetallic metal mediators can exhibit improved catalytic activity in graphitization due to the synergistic effect.3,6,7 Raney nickel alloy (Ni-Al alloy) contains 50 wt.% nickel and 50 wt.% aluminum. Individually, nickel and aluminum have shown efficacy in graphitization.8 However, no research has been conducted on the efficacy of Raney nickel alloy as a metal mediator in petcoke graphitization. We present our work on the graphitization of petcoke and its derived activated carbon using magnesium and Ni-Al alloy at 1000 °C and 1500 °C, respectively. This study assesses the effects of heating time, temperature, and precursor particle size on the degree of graphitization. Additionally, magnesium was completely removed after the graphitization process, and the residual Raney nickel alloy percentage was minimal.

Author Keywords: activated carbon, magnesium, Petroleum coke, Raney nickel alloy, synthetic graphitization