FeO・Cr_2O_3-MgO・Cr_2O_3 スピネル固溶体の成分活量

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The activity of iron chromite in solid FeO・Cr_2O_3-MgO・Cr_2O_3 spinel, saturated with Cr_2O_3, was determined at 1573 K, by the equilibrium measurement of iron dissolved in liquid silver held in the spinel crucible with CO-CO_2 gas mixture, to clarify the thermodynamic properties of chromium ores used in ferrochromium industry. The solubility of Cr_2O_3 in FeO・Cr_2O_3-MgO・Cr_2O_3 spinel phase was found to be negligibly small. The free energy of formation of FeO・Cr_2O_3 was determined as follows ; Fe(s)+1/2O_2(g)+Cr_2O_3(s)=FeO・Cr_2O_3(s), ⊿G°=-307600+66.82T (J/mol). (1423-1723K) The activities of constituents in FeO・Cr_2O_3-MgO・Cr_2O_3 spinel solid solution coexisted with Cr_2O_3 showed negative deviation from ideality. It was observed that the spinel solid solution took regular solution behavior, and α-function of FeO・Cr_2O_3-MgO・Cr_2O_3 system was determined as follows ; α_<FeO・Cr_2O_3>=RTlnγ_<FeO・Cr_2O_3>/(1-N_<FeO・Cr_2O_3>)^2=α_<MgO・Cr_2O_3>=RTlnγ_<MgO・Cr_2O_3>/(1-N_<MgO・Cr_2O_3>)^2=-12800 (J).
社団法人日本鉄鋼協会の論文
1994-07-01