Effect of Boron on the Evolution of Petroleum Coke Active Pore Size Under Air Oxidation

Petroleum cokePetroleum coke is one of the principal constituents of carbon anodeCarbon anode, used in the Hall–Héroult processHall-Héroult process which is overconsumed by air and CO2 reactions. The inhibition of the air reaction by adding boron on cokeCoke particles could be an effective technique to reduce carbon consumption. This work aims at revealing whether boron impregnationBoron impregnation affects the cokeCoke porosity and, in this eventuality, how it influences its air reactivity. The porosity of impregnated and unimpregnated samples was characterized in several pore size ranges, measured by mercury porosimetry. The pore volume variation of each pore size range as a function of carbon conversion was assessed and used to determine the range of the most active pores for air oxidation. It has been confirmed that boron blocks small pores, within the size range of 0.0004–0.025 µm. The active pores, being in the range of 0.1–10 µm, were however not affected by boron addition.