Thermodynamic optimization of the (Na2O+SiO2+NaF+SiF4) reciprocal system using the Modified Quasichemical Model in the Quadruplet Approximation

Thermodynamic modeling of the (Al2O3+Na2O), (Al2O3+Na2O+SiO2), and (Al2O3+Na2O+AlF3+NaF) systems

“…The properties of the liquid solution in the multicomponent system are adjusted with the extrapolation of binary parameters, in common ion and reciprocal systems, as described in [8], and with ternary parameters. The extrapolation of the model parameters requires the use of composition variables, v ij=k 2 and n ij=k 2 , described in [4,8], which affect the composition dependence of Dg AB=XY in all reactions similar to reactions (1) and (2). Recent modifications [9] for the extrapolation of model parameters in reciprocal systems have been presented in [2].…”

“…The extrapolation of the model parameters requires the use of composition variables, v ij=k 2 and n ij=k 2 , described in [4,8], which affect the composition dependence of Dg AB=XY in all reactions similar to reactions (1) and (2). Recent modifications [9] for the extrapolation of model parameters in reciprocal systems have been presented in [2]. In common ion multicomponent systems, the extrapolation of binary parameters is made in each ternary subsystems according to two different possibilities [8]: a symmetric one and an asymmetric one, similar to the Kohler [10] and the Kohler-Toop [11] equations respectively.…”

“…However no exact mathematical expression is known for DS config and the entropy of configuration has been approximated by Pelton et al [4]. Recent improvements of this approximation have been made by Pelton et al [9] and presented elsewhere [2]. An additional parameter, f i/k , has been introduced and the recommended values [2] have been adopted in the present work for all unary quadruplets.…”

“…This approach requires the thermodynamic modeling of the liquid and the solid solutions as well as the description of the thermodynamic properties of the stoichiometric compounds and gaseous species at all compositions and temperatures in the (Al 2 O 3 + Na 2 O + SiO 2 + AlF 3 + NaF + SiF 4 ) quaternary reciprocal system. In the scope of this thermodynamic approach to the corrosion of the cathode lining, two systems have been previously assessed: (Na 2 O + SiO 2 + NaF + SiF 4 ) [2] and (Al 2 O 3 + SiO 2 + AlF 3 + SiF 4 ) [3].…”

“…The present study focuses on the thermodynamic modeling of the (Al 2 O 3 + Na 2 O), (Al 2 O 3 + Na 2 O + SiO 2 ), and (Al 2 O 3 + Na 2-O + AlF 3 + NaF) systems using the previously assessed systems [2] and [3], and model parameters from Chartrand and Pelton [1] for (AlF 3 + NaF).…”