Critical thermodynamic evaluation of oxide systems relevant to fuel ashes and slags: Potassium oxide–magnesium oxide–silica

The K2O–MgO–SiO2 system has been thermodynamically assessed. The modified associate species model was applied to the liquid phase while the solubility of SiO2 in K2MgSiO4 has been treated with a multi-sublattice model. The resulting new databank was used for the representation of the phase equilibria in the ternary system including several quasi-binary sections of the ternary diagram. The calculated phase relations are in good agreement with the experimental data. The phase equlibria in the unmeasured region were proposed on the basis of the obtained new databank

Thermodynamic assessment of the CaO–P2O5–SiO2–ZnO system with special emphasis on the addition of ZnO to the Ca2SiO4–Ca3P2O8 phase

The CaO–P2O5–SiO2–ZnO system including all binary and ternary sub-systems has been thermodynamically assessed using all available experimental data. Particular attention was given to the phase C2S–C3P which forms a complete solid solution with end-members α-Ca2SiO4 and α′-Ca3P2O8. In addition, the present modelling of the phase C2S–C3P allows the inclusion of experimentally determined solubility values of zinc oxide in both end-members of the phase C2S–C3P. The mutual solubility between different crystallographic modifications of calcium and zinc phosphates is also described in this work using available experimental data. 24 phospates as stoichiometric phases have also been included in the database

Addition of TiO2 and Ti2O3 to the Al2O3-FeO-Fe2O3-MgO System

The Al2O3-FeO-Fe2O3-MgO-TiO2-Ti2O3 system has been thermodynamically assessed using all available experimental data. Titanium was introduced into the thermodynamic description of the liquid phase as well as of solid solution phases such as MeO, Cubic Spinel, Titania Spinel, Corundum and Pseudobrookite. Particular attention was given to the phase Cubic Spinel which forms a wide miscibility range amongst Fe3O4-TiFe2O4-TiMg2O4-TiMn2O4. In addition, the present modelling of the phase Pseudobrookite allows the description of the experimentally determined mutual solubility between Al2TiO5, MgTi2O5, FeTi2O5, Fe2TiO5 and Ti3O5. 9 titanates as stoichiometric phases have also been included in the database