The activity of iron chromite in solid FeO·Cr2O3-MgO·Cr2O3 spinel, saturated with Cr2O3, was determined at 1573 K, by the equilibrium measurement of iron dissolved in liquid silver held in the spinel crucible with CO-CO2 gas mixture, to clarify the thermodynamic properties of chromium ores used in ferrochromium industry. The solubility of Cr2O3 in FeO·Cr2O3-MgO·Cr2O3 spinel phase was found to be negligibly small. The free energy of formation of FeO·Cr2O3, was determined as follows: Fe(s)+ 1/2 O2(g)+Cr2O3(s) = FeO·Cr2O3(s), ΔG° = -307600+66.82 T (J/mol). (1423-1723 K) The activities of constituents in FeO·Cr2O3-MgO·Cr2O3 spinel solid solution coexisted with Cr2O3 showed negative deviation from ideality. It was observed that the spinel solid solution took regular solution behavior, and α-function of FeO·Cr2O3-MgO·Cr2O3 system was determined as follows; αFeO·Cr(2)O(3) = RTInγFeO·Cr(2)O(3) (1-NFeO·Cr(2)O(3))2 = αMgO·Cr(2)O(3) = RTInγMgO·Cr(2)O(3)/ (1-NMgO·Cr(2)O(3))2 = -12800 (J).
|Number of pages||6|
|Journal||Tetsu-To-Hagane/Journal of the Iron and Steel Institute of Japan|
|Publication status||Published - 1994 Jul|