Properties of Bio-pitch and Its Wettability on Coke

Bio-pitch, driven from biomass, is a potential green alternative of coal-tar-pitch in the production of carbon anodes for the aluminum electrolysis process. Information on the wetting capacity of bio-pitch on the surface of the coke particle is of great interest in assessing its possible use as a renewable and environment-friendly binder. In this study, the wettability of various bio-pitches and one reference coal-tar-pitch on the same type of coke was investigated at a temperature of 178 °C using a sessile-drop setup. Bio-oil, the parental material of the bio-pitch, was produced by commercial pyrolysis from woody biomass. Postpyrolysis treatment was run to synthesize 10 different pitch samples from bio-oil, i.e., bio-pitches. Various techniques were used to analyze the physical and chemical characteristics of the bio-pitch samples and their interactions with coke. It was shown that the wettability of bio-pitch is highly influenced by its viscosity, surface tension, surface chemical functional groups, amount of quinoline insoluble, and molecular weight distribution.