Current status and future potential of bio-pitch as binder in carbon anodes for aluminum production; A review

The aluminum industry is a significant contributor to global greenhouse gas emissions partly due to the consumption of fossil-derived carbon anodes in the Hall-Héroult electrolytic process. This review explores the reported studies on bio-pitch (BP) as a sustainable alternative to conventional coal tar pitch (CTP) and petroleum pitch (PP) binders used for the manufacturing of carbon anodes. Particular focus is on the fundamental physical and chemical properties of BP compared to traditional binders. The present review showed that while BP typically exhibits higher oxygen content and lower coking values than CTP, modification strategies, including the use of additives or metallic catalysts, can effectively align its coking value, quinoline insoluble (QI) content, density, viscosity, and softening point with industrial standards. The article concludes that while BP is a technically viable alternative to CTP, its industrial adoption requires the optimization of large-scale baking cycles and long-duration trials to ensure mechanical integrity and smooth operation. Ultimately, BP offers a strategic pathway toward carbon-neutral aluminum production, if feedstock and production parameters are carefully managed.