An initialization-improved equilibrium constant method was used for modelling the copper matte smelting process with flash technology. Initial molar amounts of species were calculated by distributing the amounts of given elements. The species containing the largest amount of one element was chosen to be the corresponding thermodynamic component. The equilibrium values were derived via the Newton−Raphson method and converted to industrial forecast values using the mechanical entrainment equations. The results indicate that the calculated equilibrium value for copper concentration in the slag is 0.32 wt.%, while the industrial forecast value is 1.03 wt.%, with the industrial value being 1.13 wt.%. The present model required only 31 outer loops to derive the approximate solution close to the equilibrium value. The iterative path during the computation is considerably reduced and the risk of non-convergence during the computation is decreased.