Arthur D. Pelton

FactSage Thermochemical Software and Databases

Abstract This paper presents a summary of the FactSage thermochemical software and databases. FactSage was introduced in 2001 and is the fusion of the FACT-Win/F∗A∗C∗T and ChemSage/SOLGASMIX thermochemical packages that were founded over 25 years ago. The FactSage package runs on a PC operating under Microsoft Windows® and consists of a series of information, database, calculation and manipulation modules that enable one to access and manipulate pure substances and solution databases. With the various modules one can perform a wide variety of thermochemical calculations and generate tables, graphs and figures of interest to chemical and physical metallurgists, chemical engineers, corrosion engineers, inorganic chemists, geochemists, ceramists, electrochemists, environmentalists, etc. In this article emphasis is placed on the calculation and manipulation of phase diagrams. However the reputation of FactSage has been established mainly in the field of complex chemical equilibria and process simulation where the software has unique capabilities. Some of these capabilities are also shown in this paper.

Thermodynamic analysis of ordered liquid solutions by a modified quasichemical approach—Application to silicate slags

A system of semi-empirical equations has been developed for the analysis of the thermodynamic properties of ordered liquid solutions such as slags. The equations, which are based upon modifications of the quasichemical theory, take into account the concentration and temperature dependence of the solution properties of ordered systems and thus enhance the reliability of interpolations and extrapolations of data. For binary systems, these equations have been coupled with an optimization computer program to analyze simultaneously all available thermodynamic data including phase diagrams, Gibbs energies and enthalpies of formation of compounds, activities, enthalpies of mixing, entropies of fusion, miscibility gaps,etc. In this manner, data for several binary slag systems have been analyzed. In the present article, analyses for the CaO-SiO2, FeO-SiO2, and CaO-FeO systems are presented. The resulting equations represent all the binary data, including the phase diagrams, essentially within experimental error limits. The calculations have been extended to ternary systems, thereby permitting ternary thermodynamic properties to be approximated solely from data from the subsidiary binary systems. Results for the SiO2-CaO-FeO system are in excellent agreement with measured ternary data.

Phase Diagrams and Thermodynamic Properties of the 70 Binary Alkali Halide Systems Having Common Ions

A very extensive literature survey of all available phase diagram and thermodynamic data has been carried out for all 40 possible common‐anion binary systems (AX‐BX) and all 30 possible common‐cation binary systems (AX‐AY) involving the alkali halides (A,B =Li,Na,K,Rb,Cs; X,Y=F,Cl,Br,I). A critical analysis and evaluation of these data have been performed with a view to obtaining a ‘‘best’’ evaluated phase diagram and a set of ‘‘best’’ evaluated thermodynamic parameters for each system. To this end, a computer‐assisted coupled analysis of the phase diagram data and the thermodynamic data for each system has been employed. Mathematical expressions for the thermodynamic properties of all known phases have been obtained which are consistent with the measured thermodynamic properties and phase diagrams as well as with established thermodynamic principles and theories of solution behavior. The parameters of these expressions are reported here and have been used to generate the computer‐calculated diagrams in t...

Coupled thermodynamic-phase diagram assessment of the rare earth oxide-aluminium oxide binary systems

Abstract A critical assessment of the binary R 2 O 3 -Al 2 O 3 systems (RLa, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu) has been carried out through the technique of coupled thermodynamic-phase diagram analysis. Thermodynamic properties of the various compounds and of the liquid oxide solutions have been deduced and optimized phase diagrams have been calculated.

Critical evaluation and optimization of the thermodynamic properties and phase diagrams of the CaO-Al2O3, Al2O3-SiO2, and CaO-Al2O3-SiO2 systems

All available thermodynamic and phase diagram data have been critically assessed for all phases in the CaO-Al2O3, Al2O3-SiO2, and CaO-Al2O3-SiO2 systems at 1 bar pressure from 298 K to above the liquidus temperatures. All reliable data for the binary systems have been simultaneously optimized to obtain, for each system, one set of model equations for the Gibbs energy of the liquid slag and all solid phases as functions of composition and temperature. The modified quasichemical model was used for the slag. With these binary parameters and those from the optimization of the CaO-SiO2 system reported previously, the quasichemical model was used to predict the thermodynamic properties of the ternary slag. Two additional small ternary parameters were required to reproduce the ternary phase diagram and ternary activity data to within experimental error limits. The calculated optimized phase diagram and thermodynamic properties are self-consistent and are the most reliable currently available estimates of the true values.

A general geometric thermodynamic model for multicomponent solutions

Several “geometric” models have been proposed for estimating thermodynamic properties of a ternary solution from optimized data for its binary subsystems. The most common are the Kohler, Muggianu, Kohler/Toop, and Muggianu/Toop models. The latter two are “asymmetric” in that one component is singled out, whereas the first two are “symmetric”. The use of a symmetric model when an asymetric model is more appropriate can often give rise to errors. There are 64 possible simple geometric models for a ternary system. Equations are developed to calculate the thermodynamic properties of an N-component solution (N>3) in a rational manner while permitting complete flexibility to choose any of the 64 possible geometric models for any ternary subsystem. An improved general functional form for “ternary terms” in the excess Gibbs energy expression is also proposed.

Thermodynamic analysis of binary liquid silicates and prediction of ternary solution properties by modified quasichemical equations

Modified quasichemical equations, developed for the analysis of the thermodynamic properties of structurally ordered liquid solutions, are shown to be well-suited for use with molten silicates. For binary systems, these equations have been coupled with a least-squares optimization computer program to analyze simultaneously all thermodynamic data including phase diagrams, Gibbs energies and enthalpies of formation of compounds, activities, enthalpies of mixing, entropies of fusion, miscibility gaps, etc. In this manner, data for several binary systems have been analyzed and represented with a small number of parameters. In the present article, results for the SiO/sub 2/-MgO, SiO/sub 2/-Na/sub 2/O and MgO-CaO systems are presented. The resulting equations represent all the binary data, including the phase diagrams, within or virtually within experimental error limits. From the modified quasichemical equations for ternary systems, ternary thermodynamic properties can be approximated solely from data from the subsidiary binary systems. Results for the SiO/sub 2/-CaO-Na/sub 2/O, SiO/sub 2/-CaO-MgO, and SiO/sub 2/-MgO-FeO systems are in excellent agreement with measured ternary data. Predictions for the quaternary system SiO/sub 2/-MgO-CaO-Na/sub 2/O are also presented.

Critical evaluation and optimization of the thermodynamic properties and phase diagrams of the MnO−TiO2, MgO−TiO2, FeO−TiO2, Ti2O3−TiO2, Na2O−TiO2, and K2O−TiO2 systems

All available thermodynamic and phase diagram data have been critically assessed for all phases in the MnO-TiO2, MgO-TiO2, FeO-TiO2, Ti2O3-TiO2, Na2O-TiO2, and K2O-TiO2 systems at 1 bar pressure from 298 K to above the liquidus temperatures. All reliable thermodynamic and phase diagram data have been simultaneously optimized to obtain, for each system, one set of model equations for the Gibbs energy of the liquid slag as a function of composition and temperature and equations for the Gibbs energies of all compounds as functions of temperature. The modified quasichemical model was used for the molten slag phases.

A modified interaction parameter formalism for non-dilute solutions

A simple modification of the interaction parameter formalism for the thermodynamics of dilute solutions is proposed. The modified formalism reduces exactly to the standard formalism at infinite dilution and preserves the notation as well as the numerical values of the parameters. Hence, existing compilations of interaction parameters can be used directly in the modified formalism. However, the modified formalism is thermodynamically consistent at finite concentrations, whereas the standard formalism is not. Equations for first-order and higher-order modified formalisms are presented for systems of any number of components. In the first-order modified formalism: {fx1211-01}

A structural model for binary silicate systems

A structural model is presented for binary silicate systems of the typeMO-SiO2, whereMO is a basic oxide, in which silicate tetrahedra and oxygen “bridges” are treated as structural units. One single formalism applies over the entire composition range from pureMO, where the model reduces to a simple orthosilicate anion model, to pure SiO2, where the model reduces to a simple model of the breaking of oxygen “bridges” upon the addition ofMO. At intermediate compositions, chain length distributions for silicate polymer chains can be calculated from the model, even though these polymeric chains are not explicitly treated as structural units of the model. The calculated chain length distributions are in very good agreement with those calculated from the polymeric model of Masson for all systems studied. Furthermore, two dimensional (cyclic) and three dimensional (network) polymeric structures are accounted for by the present model. The model accounts well for available enthalpy, entropy, activity, and phase diagram data in the binary liquid systemsMO-SiO2 whereM = Ca, Mg, Mn, Fe, or Pb. The observed variations of ΔH with composition and from system to system are explained in terms of the energies of the various bonds and are represented by a three parameter equation. Although the model has been tested here only for liquid slags, it should be useful in understanding the structure of silicate glasses as well.