Effect of α-Al₂O₃ Nanoparticles on the Thermophysical Properties of Coal Tar Pitch Binder for Carbon Anode in Aluminum Manufacturing

Coal Tar Pitch (CTP) is a critical binder in preparing carbon anodes for primary aluminum manufacturing via the Hall–Héroult process. Its thermophysical properties strongly influence the final quality, energy efficiency, and performance of the anodes. The effect of incorporating α-Al₂O₃ nanoparticles (average diameter ≈۵۰ nm) at concentrations of ۰.۵, ۳, and ۵ wt.% into CTP on key properties was investigated, including softening point, density, viscosity (at ۱۳۵°C and ۱۷۵°C), and coking value. We compared two preparation methods: thermal blending (۱۷۰ °C-۱۸۰ °C) and solvent-based blending (ethanol-water mixture). The solvent-based method was selected for further experiments due to comparable effectiveness with superior nanoparticle dispersion and lower energy consumption. This work focuses exclusively on the binder material (CTP) as the first step toward understanding nanoparticle-modified binders for anode applications. Results revealed that ۰.۵ wt.% α-Al₂O₃ addition yielded optimal improvements: softening point increased from ۱۱۴.۷ °C to ۱۱۵.۵ °C, density increased from ۱.۳۱۳ to ۱.۳۲۸ g/cm³, and coking value improved from ۵۵ to ۵۸ wt.%, while viscosity remained within the operational range required for industrial anode manufacturing (۰.۴-۱.۵ Pa·s at ۱۷۵°C). These findings indicate that incorporating ۰.۵ wt.% α-Al₂O₃ nanoparticles can enhance the thermophysical stability and carbon yield of CTP, offering potential improvements in anode quality and energy efficiency in aluminum manufacturing. Full anode fabrication and electrochemical performance evaluation are beyond the scope of this study and will be addressed in future work.

کلیدواژه ها:

Coal tar pitch ، &alpha ، -Al₂O₃ nanoparticles ، Thermophysical properties ، Carbon anode ، Aluminum smelter