THE FACT FTsulf DATABASES

For nearly all calculations involving sulfide solutions, the FTsulf databases supersede the FTmisc databases. In particular for calculations involving matte smelting, the FTsulf databases will provide better results in nearly all cases due to many improvements to the optimizations [2135-2139, 4023-4028, 4031-4035].  For example, the MAT2 phase is now more consistent with the FToxid and FSstel databases, contains oxygen as a component, and can be used at all compositions from pure metal to pure sulfide.           

The FTsulf databases contain solutions and stoichiometric compounds evaluated/optimized by the FACT group for applications involving equilibria among metal, liquid and solid sulfide phases, liquid and solid oxide phases and gas. This includes pyrometallurgy, hot corrosion, etc. The FTsulf solution database (FTsulf53Soln.sda) contains sulfide solutions and three major metal solutions (liquid, bcc and fcc), which are compatible with the sulfide solutions. The FTsulf compound database (FTsulf53Base.cdb) contains all stoichiometric sulfide, sulfate and arsenide compounds evaluated/optimized by the FACT group to be thermodynamically consistent with the FTsulf solution database.

Phase selection

The FTsulf databases are consistent with FToxid and FSstel databases. Hence, for calculations of metal/sulfide/oxide/gas equilibria one should first select all phases from FTsulf, then if needed, oxide phases should be selected from FToxid and intermetallic phases should be selected from FSstel (except for the liquid, bcc and fcc metallic phases, which are present in FTsulf). If necessary, gaseous species should be selected from the FactPS database, but NO solid or liquid compounds should be selected from FactPS.

The sulfide and metal solutions in the Cu-Fe-Ni-Co-Cr-Mn-Pb-Zn-As-O-S system

Best calculations will be obtained for the following sulfide subsystems, which have been recently optimized:

· Cu-Fe-Ni-Co-Pb-Zn-S [4007, 4010, 4012, 4013, 4015, 4018, 4019, 4023, 4024, 4025, 4035]

· Cu-Fe-Ni-Co-O-S, including the solubility of oxygen in liquid sulfide (matte) and in liquid, bcc and fcc metal phases [4023, 4024, 4025, 4026, 4027, 4028]

· Cu-Fe-Pb-Zn-Ni-As-S [4031-4034]

· Fe-Cr-S

· Fe-Mn-S [4019]

Other subsystems have been approximated using the models.  The liquid phase is modeled with the modified quasichemical model [1015, 1020] which takes into account short-range-ordering.  Solid solutions are modeled using sublattice models within the Compound Energy Formalism [1026].

When calculating equilibria between sulfide and oxide phases, for example slag/matte equilibria, additional elements such as Si can be present in the system if these elements tend to remain in the oxide phases and do not dissolve substantially in the sulfide phases. In particular, the effect of Al₂O₃, CaO and MgO in the slag phase on the distribution of Cu between matte and slag can be calculated [4027, 4028].

The following solutions and compounds form a thermodynamically self-consistent set of phases within this optimization:

Liquid sulfide      [FTsulf-MAT2] – all compositions from pure metal to pure sulfur

Beta-Ni₃S₂           [FTsulf-M3S2] – non-stoichiometric (Fe,Ni,Cu,Va)₂S solution

Pyrrhotite            [FTsulf-Pyrr] – non-stoichiometric  (Cu,Fe,Ni,Co,Cr,Mn)S_1+x solution

(Fe,Cu,Ni)S₂       [FTsulf-MeS2] – pyrite solution

Pentlandite          [FTsulf-Pent] – (Fe,Ni,Cu)₉S₈ solution

CuMS                  [FTsulf-CuMS]  – Intermediate solution Cu-Fe-Ni-S.

                            This solution phase does not emanate from any of the binary subsystems

Covelite               [FTsulf-Cove] – CuS-FeS based solution with CuS as major component

Digenite/Bornite  [FTsulf-Dgnt] – Cu_2-xS-NiS-FeS-PbS-ZnS solid solution.

Villamaninite       [FTsulf-Vill] – CuS₂-NiS₂-FeS₂ solid solution

Millerite              [FTsulf-Mill] – NiS-CuS solid solution

Polydymite          [FTsulf-SpiS] – Ni₃S₄-Cu₃S₄ thiospinel

Sphalerite            [FTsulf-SPHA] – Solid ZnS with FeS in solution

Wurtzite              [FTsulf-WURT] – Solid ZnS with FeS in solution

MeS_cubic          [FTsulf-MS-c] – (Mn,Fe,Ca,Mg,Cr,Pb,Cu)S solution with cubic rocksalt structure

FCC                     [FTsulf-FCCS] – fcc metal solution Co-Cr-Cu-Fe-Mn-Ni-Pb-Zn, dilute As,O,S

BCC                    [FTsulf-BCCS] – bcc metal solution Co-Cr-Cu-Fe-Mn-Ni-Pb-Zn, dilute As,O,S

and the following stoichiometric compounds from the FTsulf compound database:

CrS, Cr₂S₃, NiS, NiS₂ (end member of MeS2 solution), Ni₃S₂, Ni₃S₄, Ni₇S₆, Ni₉S₈, FeS, FeS₂ (end member of MeS2 solution), Fe₇S₈, Fe₉S₁₀, Fe₁₀S₁₁, Fe₁₁S₁₂, FeCr₂S₄, CoS, CoS₂ (end member of MeS2 solution), Co₃S₄, Co₉S₈, CuS (end member of Cove solution), Cu₂S, CuFeS₂, CuFe₂S₃, Cu₃FeS₄, Cu₃FeS₈, Cu₄Fe₅S₈, Cu₉Fe₈S₁₆,Cu₉Fe₉S₁₆, Cu₁₁Fe₂S₁₃, MnS (end member of MS-c solution), MnS₂, PbS, ZnS, solid and liquid S, solid and liquid As, As₂S₃, As₄S₃, As₄S₄, FeAs, Fe₂As, FeAs₂, Fe₅As₄, NiAs, NiAs₂, Ni₅As₂, Ni₁₁As₈, Cu₃As, Cu₈As, Cu₅As₂, CuAsS, Cu₃AsS₃, Cu₃AsS₄, Cu₆As₄S₉, ZnAs₂, Zn₃As₂, FeSO₄, Fe₂(SO₄)₃, NiSO₄, CuSO₄, Cu₂SO₄, (CuO)(CuSO₄).

See detailed description under “Description of solutions.”