Effect of Mixing and Pressing Parameters on the Properties of Biopitch-Based Lab-Scale Carbon Anodes for Use in the Hall-Héroult Electrolytic Cell

Biopitch (BP) is being developed as a potential replacement for coal-tar pitch (CTP) in carbon anodes for primary aluminium production. Since the softening point (SP) of BP is lower than that of CTP, the mixing temperature can possibly be lowered, not only to save thermal energy but also to optimize the mixing parameters. The goal of the current study was to investigate the effect of mixing and pressing variables on BP-based carbon anode properties. Anode pastes were made while varying four different production parameters according to a two-level full factorial design of experiment: BP/Coke mass ratio 16–20%, mixing temperature 160–180 °C, mixing time 8–12 min, and pressing temperature 130–150 °C. The green apparent density (GAD), the baked apparent density (BAD), and the specific electrical resistivity (SER) of the baked samples were measured using standard test methods. Improved production parameters are suggested to achieve high GAD, BAD, and low SER.