Calculation and prediction of components activities and activity coefficients for Al–Fe and Al–Si binary alloy

Abstract This study employed the Wilson, non-random two-liquid model (NRTL), and molecular interaction volume model models combined with the Newton–Raphson iteration method to calculate the activity coefficients of Al and Fe in Al–Fe binary alloys, as well as those of Al and Si in Al–Si binary alloys. According to research conclusions, the NRTL model proves to be more precise and dependable than the other two models when employed in the computation of Al–Fe and Al–Si binary alloy systems. Consequently, this research selected the NRTL model to predict the activity coefficients and activities within the temperature range of 1373 K to 2173 K, enriching the thermodynamic data for aluminum-based alloy components. Furthermore, vapor–liquid equilibrium (VLE) phase diagrams for Al–Fe and Al–Si alloys were plotted, and the vacuum distillation method was proposed for purifying metallic aluminum. The VLE data suggest that vacuum distillation can effectively separate Al from Fe or Al from Si, facilitating the production of high-purity aluminum. This study provides a predictive model for the separation of Al–Fe and Al–Si alloys based on vacuum distillation, offering significant references for analyzing the separation limits of aluminum in these alloys, the thermodynamic properties of their components, and the internal reactions between elements in aluminum-based alloys.