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Liquid–Solid Equilibria in the System FeO–NiO–Fe 2 O 3 –SiO 2
Author(s) -
Grutzeck Michael W.,
Muan Arnulf
Publication year - 1992
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1992.tb04192.x
Subject(s) - liquidus , cristobalite , spinel , solid solution , tridymite , eutectic system , oxide , solidus , non blocking i/o , mineralogy , materials science , phase diagram , triple point , phase (matter) , analytical chemistry (journal) , thermodynamics , chemistry , metallurgy , alloy , quartz , biochemistry , physics , catalysis , organic chemistry , chromatography
Liquidus and solidus phase relations have been determined for the system NiO‐iron oxide–SiO 2 in air and in CO 2 . In both cases the system is simple in that it contains only three primary crystalline phases: spinel (Fe 3 O 4 –NiFe 2 O 3 solid solution), oxide (“FeO”–NiO solid solution) and SiO 2 , either tridymite or cristobalite. There is only one liquidus invariant point at which the above crystalline phases coexist with liquid (and the gas phase). In air, the invariant point (a eutectic) is at 1524°C, and a temperature maximum is present along the spinel–silica liquidus boundary curve at 1540°C. In CO 2 , the silica + spinel + oxide + liquid invariant temperature is considerably lower: 1433°C. Combination of these data with those obtained previously for the same system under strongly reducing conditions (CO 2 –CO gas mixtures of ratios only slightly above those of equilibrium coexistence of the oxide phases with Fe–Ni alloy) makes it possible to draw the main features of phase relations in the quaternary system FeO–NiO–Fe 2 O 3 –SiO 2 . This system also is relatively simple, in that only five crystalline phases are present in equilibrium with liquids, viz, silica (cristobalite or tridymite), olivine (Fe 2 SiO 4 ‐Ni 2 SiO 4 solid solution), spinel (Fe 3 O 4 ‐NiFe 2 O 4 solid solution), hematite (Fe 2 O 3 ), and oxide (“FeO”–NiO solid solution). There is only one quaternary liquidus invariant point in the system, characterized by the equilibrium coexistence of silica, olivine, spinel, oxide, and liquid, at a temperature of ∼ 1410°C and an oxygen pressure of the gas phase of ∼10 −5 atm.