The solubility and activity determination of NiO in the SiO2–NiO–FeO system

A structural model for the liquid phase of silicate systems was used to obtain the SiO2–NiO–FeO phase diagram and the NiO activities at 1573 and 1673 K. The NiO activities were determined experimentally by equilibrating a pure nickel crucible with an iron-silicate slag and CO–CO2 gas mixture to produce pO2 = 10−6 and 10−10 atm. The NiO activities obtained by the structural model are in good agreement with those obtained experimentally for strongly reduction conditions (10−10 atm), due to the structural model consider only the iron in the divalent state. The Fe3+/Fe2+ ratio and the nickel oxide solubility were increased when the oxygen partial pressure and the temperature were increased.