SOLUTIONS IN FThall

 

[FILE]

[FThall-Bath]

Base:                  FThall

Phase:                Bath

Full Name:          ABath or BBath

 

 

Bath NaF-AlF3-CaF2-LiF-MgF2-Al2O3-Al4C3-Na2CO3 + dissolved metal

(uncertainties above 1100oC or CR>5 or CR<1.5)

 

Components:                                       

FThall-BathA:          NaF, AlF3_5coord, AlF3_4coord, Al2F6, CaF2, LiF, MgF2,

                                  Na2O, Al2O3_5coord, Al2O3_4coord, Al2O3, CaO, Li2O, MgO,

                                  Na, Al_5coord, Al_4coord, Al2, Ca, Li, Mg

FThall-BathB:          NaF, AlF3_5coord, AlF3_4coord, Al2F6, CaF2,

                                  Na2O, Al2O3_5coord, Al2O3_4coord, Al2O3, CaO,

                                  Na4C, Al4C3_5coord, Al4C3_4coord, (Al2)2C3, Ca2C,

                                  Na2CO3, Al2(CO3)3_5coord, Al2(CO3)3_4coord, Al2(CO3)3, CaCO3,

                                  Na, Al_5coord, Al_4coord, Al2, Ca

Selection Type:          I (possible 2-phase immiscibility)

 

 

This solution corresponds to the liquid electrolyte Na3AlF6-AlF3-Al2O3-CaF2-LiF-MgF2-Al4C3-Na2CO3FThall-BathA corresponds to the fluoride-oxide melt and takes into account metal dissolution when metal is equilibrated with the bath. If one is interested in the fluoride-oxide melt in absence of dissolved metal (i.e. if no metal is equilibrated with the bath), then one should use FThall-BathA and deselect manually all the following “end-members” (or pseudo-components) that correspond to dissolved metal : Na, Al_5coord, Al_4coord, Al2, Ca, Li, Mg. This will significantly speed up the calculations. If no such deselection is made, then the calculations will require more time but they will remain unchanged if no metal is equilibrated with the bath. FThall-BathB should be used to take into account the solubility of Al4C3 in presence of dissolved metal (with Al4C3(s) and Al4O4C(s) saturations) and the solubility of CO2(g) (in the form of carbonates) in the NaF-AlF3-CaF2-Al2O3 base electrolyte.

 

FThall-Bath? needs not be used.

 

Never select FThall-Bath simultaneously with FTsalt-SALT or FTsalt-SAL2.

 

The Modified Quasichemical Model in the Quadruplet Approximation has been used for this solution.  The model assumes a non-random mixing of elemental cations and anions on their respective sublattices.  1st and 2nd nearest-neighbour short-range order is calculated by the model by modifying the configurational entropy as a function of 1st and 2nd nearest-neighbour pair energies.

 

Cations:  Na+, Al3+(5 coordinated), Al3+(4 coordinated), Al26+ (2 bridged Al3+), Li+, Ca2+ and Mg2+

 

Anions: F-, O2-, Va-, C4- and CO32-

 

Al3+(4 coordinated) is conceptually related to "AlF4-". Al3+(5 coordinated) is conceptually related to "AlF52-". Al3+(6 coordinated) is neglected in the model, so the highest coordination of Al3+ is 5. (This is a limitation of the model). Al3+(6 coordinated) has been neglected because tests showed that its inclusion did not improve the fits to the experimental phase diagram and thermodynamic property data, and increased the complexity of the model which is intended for large database development. Va- is a charged vacancy or electron temporarily located on an anionic position (F-center) whose presence is equivalent to excess metal dissolution in the salt melt.

 

A density model and a viscosity model are available for the NaF-AlF3-CaF2-Al2O3-LiF-MgF2 electrolyte as a function of temperature and composition. In the Menu Window of Equilib, select the liquid solution FThall-BathA and check the box “include molar volumes”. In the Results Window, the density value (in gram/cm3) calculated from the model is displayed (in parentheses) at the 2nd line of the block corresponding to the liquid phase. A system density (in gram/cm3) that takes into account the available density data for all phases at equilibrium (liquid + 1 or more solid phases) is displayed below the integral property table. The viscosity value (in Pa.s) calculated from the model is displayed at the end of the block corresponding to the liquid phase.

 

Limitations:

 

1                    NaF-AlF3-[Na-Al]: the model covers the whole liquid range for P < 3 atm (the Na-NaF liquid miscibility gap cannot be "closed" at high pressures).

2                    NaF-AlF3-Al2O3: the model has good predictive capabilities for CR < 5 and CR > 1.5 and for T < 1100oC. A spurious miscibility gap appears for very high CR at NaAlO2-NaAl9O14 co-saturation.

3                    In the oxide-free system, the model covers the whole range of composition in the LiF-NaF-MgF2-CaF2-AlF3 system but predictions in the LiF-MgF2-AlF3 system rich in AlF3 are not very good. The error in the calculated liquidus of  

              AlF3 may also be large in the CaF2-AlF3 system.

4                    Metal dissolution outside the NaF-AlF3-Al2O3 system is approximate.

5            Density and viscosity models for the NaF-AlF3-CaF2-Al2O3-LiF-MgF2 electrolyte : results are less satisfactory for very acidic baths (CR = molar ratio NaF / AlF3 < 1.50).

 

Figures:

NaF_AlF3.fig

Na3AlF6_Al2O3.fig

CaF2_AlF3.fig

LiF_AlF3.fig

MgF2_AlF3.fig

NaF_CaF2.fig

NaF_MgF2.fig

LiF_NaF.fig

LiF_CaF2.fig

LiF_MgF2.fig

MgF2_CaF2.fig

Na3AlF6_Li3AlF6.fig

 

References: 1022, 3012, 3025, 3032, 3037

 

 

[FThall-CryH]

Base:                  FThall

Phase:                CryH

Full Name:          Na-Cryolite-H

 

Na-Cryolite-H Na3AlF6-Li3AlF6-AlF3-CaF2

High temperature non-stoichiometric cryolite

 

Components:                Na3AlF6, Na3AlF4[2+], AlF4[-], AlF6[3-], Ca3AlF6[3+],

                                     Ca3AlF4[5+], Li3AlF6, Li3AlF4[2+]

Selection Type:             + (single phase)

 

 

This solution corresponds to the non-stoichiometric high-temperature solid Na3AlF6 dissolving excess AlF3, CaF2 and Li3AlF6. It is stable above 525oC and below 1020oC.

 

A two-sublattice model with the following ions has been used:

 

Cations:            Na+, Li+, Ca2+ and Va0 (neutral vacancy)

 

Anions:            AlF63- and AlF4-

 

A charge balance, from which the Va0 concentration is calculated, is performed to ensure the electro-neutrality of the solution.

 

The conductivity of the solid solution can be calculated as a function of T and excess AlF3 using the mole fraction of cationic vacancies (XVa) calculated by EQUILIB and according to the following equation (E.W.Dewing, Metall. Trans. B, vol.9, pp.687-690, 1978):

 

Log10s = -2288 / T(K) + 4.33412 + log10XVa ohm-1   (XVa from EQUILIB output : see below)

+  0.57587     gram  (   89.771     wt.% Na3AlF6                      FThall

                     +   6.5345     wt.% Na3AlF4[2+]                  FThall

                     +  0.22520     wt.% AlF4[-]                      FThall

                     +   3.4689     wt.% AlF6[3-]                     FThall)

                        (960.00 C, 1 atm, Na-Cryolite-H, d= 2.8993 g.cm-3)

                     Mole fraction of sublattice constituents in Na-Cryolite:

                     Na[+]        0.94559

                     Va           0.54414E-01  (XVa from EQUILIB output)

                     ------------------------

                     AlF6[3-]     0.91838

                     AlF4[-]      0.81622E-01

 

Figures:

NaF_AlF3.fig

Na3AlF6_Li3AlF6.fig

 

References : 3012

 

 

 

[FThall-CryL]

Base:                  FThall

Phase:                CryL

Full Name:          Na-Cryolite-L

 

Na-Cryolite-L Na3AlF6-Li3AlF6-[Ca(1.5)AlF6]

[I] Low-temperature solid cryolite Na3AlF6 diss. Ca[2+] & Li[+]

 

Components:                Na3AlF6, AlF6[3-], Ca3AlF6[3+], Li3AlF6

Selection Type:             I (possible 2-phase immiscibility)

 

 

This solution corresponds to the low-temperature solid Na3AlF6 solution dissolving excess CaF2 and Li3AlF6. It is stable below 560oC. There is no dissolution of excess AlF3 as in CryH.

 

A two-sublattice model with the following ions has been used:

 

Cations:            Na+, Li+, Ca2+ and Va0 (neutral vacancy)

 

Anions:            AlF63-

 

A charge balance, from which the Va0 concentration is calculated, is performed to ensure the electro-neutrality of the solution.

 

Figures:

Na3AlF6_Li3AlF6.fig

 

References: 3012

 

 

 

[FThall-LiCB]

Base:                  FThall

Phase:                LiCB

Full Name:          Li-Cryolite-B

 

Li-Cryolite-B Beta-Li3AlF6 dissolving Na[+]

 

 

Components:                Li3AlF6, Na3AlF6

Selection Type:            + (single phase)

 

 

This solution corresponds to the low-temperature solid Li3AlF6b solution dissolving excess Na3AlF6. It is stable below 525oC. 

 

A two-sublattice model with the following ions has been used:

 

Cations:           Li+, Na+

 

Anions:           AlF63-

 

Figures:

Na3AlF6_Li3AlF6.fig

 

References: 3012

 

 

[FThall-LiCG]

Base:                  FThall

Phase:                LiCG

Full Name:          Li-Cryolite-G

 

Li-Cryolite-G Gamma-Li3AlF6 dissolving Na[+]

 

 

Components:                Li3AlF6, Na3AlF6

Selection Type:            + (single phase)

 

 

This solution corresponds to the low-temperature solid Li3AlF6g solution dissolving excess Na3AlF6. It is stable above 475oC and below 650oC. 

 

A two-sublattice model with the following ions has been used:

 

Cations:            Li+, Na+

 

Anions:            AlF63-

 

Figures:

Na3AlF6_Li3AlF6.fig

 

 

[FThall-LiCD]

Base:                  FThall

Phase:                LiCD

Full Name:          Li-Cryolite-D

 

Li-Cryolite-D Delta-Li3AlF6 dissolving Na[+]

 

 

Components:                Li3AlF6, Na3AlF6

Selection Type:            + (single phase)

 

 

This solution corresponds to the low-temperature solid Li3AlF6d solution dissolving excess Na3AlF6. It is stable above 625oC and below 800oC. 

 

A two-sublattice model with the following ions has been used:

 

Cations:            Li+, Na+

 

Anions:            AlF63-

 

Figures:

Na3AlF6_Li3AlF6.fig

 

 

 

[FThall-CrLt]

Base:                  FThall

Phase:                CrLt

Full Name:          Cryolithionite

 

Cryolithionite (non-stoichiometric cubic Na3Li3Al2F12 diss. excess Li3AlF6)

Use [I]-option.

 

Components:                Na3Li3Al2F12, Li3Li3Al2F12

Selection Type:             I (possible 2-phase immiscibility)

 

 

This solution corresponds to the non-stoichiometric solid Na3Li3Al2F12 solution dissolving excess Li3AlF6. It is stable below 725oC. 

 

A three-sublattice model with the following ions has been used:

 

Sublattice 1:      Na+, Li+           (sublattice stoichiometry = 3)

 

Sublattice 2:      Li+                               (sublattice stoichiometry = 3)

 

Sublattice 3:      AlF63-              (sublattice stoichiometry = 2)

 

Figures:

Na3AlF6_Li3AlF6.fig

 

 

 

[FThall-NaF]

Base:                  FThall

Phase:                NaF

Full Name:          NaF-[LiF](ss)

 

NaF-[LiF](ss) Villiaumite high NaF-content solid binary

solution – NaF; dilute LiF. Use [I]-option.

 

Components:                NaF, LiF

Selection Type:            I (possible 2-phase immiscibility)

 

This solution is the NaF-rich solid solution dissolving LiF. It may be stable below 1000oC. 

 

Do not select FThall-NaF simultaneously with any fluoride solution or fluoride compound from any database other than FThall.

 

Figures:

LiF_NaF.fig

 

 

[FThall-LiF]

Base:                  FThall

Phase:                LiF

Full Name:          LiF-[MgF2](ss)

 

LiF-[MgF2](ss) high LiF-content solid binary

solution – LiF; dilute MgF2.

 

Components:                LiF, MgF2

Selection Type:            + (single phase)

 

 

This solution is the LiF-rich solid solution dissolving MgF2. It may be stable below 850oC.

 

Do not select FThall-LiF simultaneously with any fluoride solution or fluoride compound from any database other than FThall.

 

Figures:

LiF_MgF2.fig

 

 

[FThall-MgF2]

Base:                  FThall

Phase:                MgF2

Full Name:          MgF2-[LiF](ss)

 

 

MgF2-[LiF](ss) high MgF2-content solid binary

solution – MgF2; dilute LiF.

 

 

Components:                MgF2, LiF

Selection Type:            + (single phase)

 

 

This solution is the MgF2-rich solid solution dissolving LiF. It may be stable below 1270oC.

 

Do not select FThall-MgF2 simultaneously with any fluoride solution or fluoride compound from any database other than FThall.

 

Figures:

LiF_MgF2.fig

 

 

[FThall-Liqu]

Base:                  FThall

Phase:                Liqu

Full Name:          Liquid-Alloy

 

 

Liquid-Alloy  Liquid light-metal Al,Li,C,Na,Mg,Ca

Use [I]-option

 

 

Components:                Al, C, Ca, Li, Mg, Na

Selection Type:             I (possible 2-phase immiscibility)

 

 

This solution is the liquid alloy solution. It encompasses the Al-Na miscibility gap.

 

Do not select FThall-Liqu simultaneously with any metallic phase from any database other than FThall.

 

Volumetric properties (density) as a function of temperature were entered for the Al, Ca, Li, Mg and Na pure liquids. Moreover, a density model is available for the Al-Mg binary liquid. Approximate density calculations may be performed for the entire Al-Ca-Li-Mg-Na liquid metal : all binary liquids other than Al-Mg are then assumed to be ideal (in terms of the volumetric properties). A viscosity model is available for the Al-Mg binary liquid. Currently, viscosity calculations (even approximate) CANNOT be performed for metallic systems other than Al-Mg. In the Menu Window of Equilib, select the liquid metal solution FThall-Liqu and check the box “include molar volumes”. In the Results Window, the density value (in gram/cm3) calculated from the model is displayed (in parentheses) at the 2nd line of the block corresponding to the liquid phase. A system density (in gram/cm3) that takes into account the available density data for all phases at equilibrium (liquid + 1 or more solid phases) is displayed below the integral property table. The viscosity value (in Pa.s) calculated from the model is displayed at the end of the block corresponding to the liquid phase. 

 

 

[FThall-FCC]

Base:                  FThall

Phase:                FCC

Full Name:          FCC

 

 

FCC Al-[Li,Na,Mg,Ca] solid solution

 

 

Components:                Al, Ca, Li, Mg, Na

Selection Type:            + (single phase)

 

 

This solution is the FCC Al-alloy solution dissolving Ca, Li, Mg and Na.

 

Do not select FThall-FCC simultaneously with any metallic phase from any database other than FThall.

 

 

 

 

 

[FThall-HCP]

Base:                  FThall

Phase:                HCP

Full Name:          HCP

 

 

HCP Mg dissolving Al

 

 

Components:                Mg, Al

Selection Type:            + (single phase)

 

 

This solution is the HCP Mg-alloy solution dissolving Al.

 

Do not select FThall-HCP simultaneously with any metallic phase from any database other than FThall.

 

 

 

 

[FThall-BCC]

Base:                  FThall

Phase:                BCC

Full Name:          BCC

 

 

BCC Ca,Na

Use [I]-option

 

Components:                Ca, Na

Selection Type:             I (possible 2-phase immiscibility)

 

 

This solution is the high-temperature BCC Ca-alloy solution dissolving Na. It is also the low-temperature BCC Na-alloy solution dissolving Ca.

 

Do not select FThall-BCC simultaneously with any metallic phase from any database other than FThall.

 

 

 

 

 

[FThall-AlMg]

Base:                  FThall

Phase:                AlMg

Full Name:          Gamma

 

 

Gamma Al12Mg17 gamma solid solution

Laves Phase

 

Components:                Mg10Al24Al24, Mg10Al24Mg24, Mg10Mg24Al24, Mg10Mg24Mg24

Selection Type:            + (single phase)

 

 

This solution is the intermediate Al12Mg17 solid solution often denoted “Gamma”. It usually saturates the Mg-HCP solid solution.

 

Do not select FThall-AlMg simultaneously with any metallic phase from any database other than FThall.

 

A three-sublattice model with the following atoms has been used:

 

Sublattice 1:      Mg                     (sublattice stoichiometry = 10)

 

Sublattice 2:      Al, Mg                          (sublattice stoichiometry = 24)

 

Sublattice 3:      Al, Mg               (sublattice stoichiometry = 24)

 

 

 

[FThall-Spin]

Base:                  FThall

Phase:                Spin

Full Name:          ASpinel

 

 

Spinel MgAl2O4 with dissolved Al2O3

[I]-option recommended.

 

Components:                Al3O4[+], Al1O4[5-], MgAl2O4, Al1Mg2O4[-], Mg3O4[2-], Mg1O4[6-]

Selection Type:             I (possible 2-phase immiscibility)

 

 

This solution is the spinel solid oxide solution MgAl2O4 dissolving excess Al2O3.

 

A three-sublattice model has been used with Mg2+ and Al3+ mixing on tetrahedral and octahedral sites while O2- fills the third sublattice.

 

Do not select FThall-Spin simultaneously with any spinel solution from the FToxid database.

 

Figures:

MgO_Al2O3.fig

 

 

 

[FThall-Mono]

Base:                  FThall

Phase:                Mono

Full Name:          Monoxide

 

 

Monoxide Rocksalt MgO-CaO-[Al2O3]

Use [I]-option.

 

Components:                CaO, MgO, Al2O3

Selection Type:             I (possible 2-phase immiscibility)

 

 

This solution is the CaO-MgO solid solution which exhibits a miscibility gap. It includes the dissolution of a small amount of Al2O3.

 

Do not select FThall-Mono simultaneously with FToxid-MeO_.

 

Figures:

MgO_CaO.fig

MgO_Al2O3.fig

 

 

 

 

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