Phase Equilibria in the System MgO‐Cr2O3‐SiO2

Keith, M. L.

doi:10.1111/j.1151-2916.1954.tb13981.x

Cited by 80 publications

(37 citation statements)

References 9 publications

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“…Keith [20] describes a decrease of the melting point in the system MgO-Cr 2 O 3 -SiO 2 system showing an eutectic point at 1546 C. This eutectic point is present at the composition of 34.5 wt% MgO, 1 wt% Cr 2 O 3 , and 64.5 wt% SiO 2 . As a result, the presence of the dissolved silicon and chromium in the steel melt may reduce the MgO and decrease significantly its melting point (2852 C), in this study.…”

Section: Discussionmentioning

confidence: 99%

Interactions between Exogenous Magnesia Inclusions with Endogenous Inclusions in a High Alloyed Steel Melt

et al. 2017

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Interactions between exogenous MgO particles and endogenous inclusions on the surface of a high alloyed steel melt have been investigated in situ in a high temperature confocal laser scanning microscope. Exogenous magnesia particle forms immediately a liquid Mg-Si-Al-Ti-Cr phase surrounding the solid particle. The real attraction forces between the liquid layer surrounding MgO particles and endogenous Al 2 O 3 inclusions are determined in the range of 6 Â 10 À18 N to 1 Â 10 À16 N. In contrast to earlier investigations with exogenous Al 2 O 3 particles, lower real attraction forces between exogenous and endogenous particle pairs have been observed in comparison to endogenous inclusions pairs.

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Section: Discussionmentioning

confidence: 99%

Interactions between Exogenous Magnesia Inclusions with Endogenous Inclusions in a High Alloyed Steel Melt

et al. 2017

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“…At P O 2 ϭ2.73ϫ10 Ϫ10 atm, 13) the liquidus temperature in spinel primary phase field of the MgO-CrO x -SiO 2 system was decreased by approximately 250 K compared with the system in air. 15) EPMA measurements of the liquid and solid phases present under these conditions are reported in Table 5. Liquidus isotherms in the cristobalite and tridymite primary phase fields in the MgO-"FeO"-SiO 2 system with 2 wt% Cr 2 O 3 were determined in the temperatures range from 1 723-1 873 K (Fig.…”

Section: The Mgo-"feo"-sio 2 -"Cr 2 O 3 " Systemmentioning

confidence: 99%

Effect of Al2O3 and Cr2O3 on Liquidus Temperatures in the Cristobalite and Tridymite Primary Phase Fields of the MgO-"FeO"-SiO2 System in Equilibrium with Metallic Iron

2005

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The effects of alumina and chromite impurities on the liquidus temperatures in the cristobalite/tridymite (SiO 2 ) primary phase fields in the MgO-"FeO"-SiO 2 system in equilibrium with metallic iron have been investigated experimentally. Using high temperature equilibration and quenching followed by electron probe X-ray microanalysis (EPMA), liquidus isotherms have been determined in the temperatures range 1 673 to 1 898 K. The results are presented in the form of pseudo-ternary sections of the MgO-"FeO"-SiO 2 system at 2, 3 and 5 wt% Al 2 O 3 , 2 wt% Cr 2 O 3 , and 2 wt% Cr 2 O 3 ϩ2 wt% Al 2 O 3 . The study enables the liquidus to be described for a range of SiO 2 /MgO and MgO/FeO ratios. It was found that liquidus temperatures in the cristobalite and tridymite primary phase fields, decrease significantly with the addition of Al 2 O 3 and Cr 2 O 3 .KEY WORDS: slag; liquidus; phase equilibria; MgO-"FeO"-SiO 2 -Al 2 O 3 -Cr 2 O 3 system. ExperimentalThe experimental procedure used in the present investigation is one that has been developed specifically to provide accurate liquidus data in complex slag systems.7-9) The details of the procedure as adopted specifically for slags in the system under investigation are given in previous publication by the present authors.1) The procedure essentially involves the preparation of the synthetic slag compositions from high purity oxide and metallic iron powders; high temperature equilibration in Mo or Fe foil with metallic iron excess in a neutral gas atmosphere (temperature is within Ϯ2 K); rapid quenching of the samples enabling the phases present at temperature to be retained at room temperature; and determination of the compositions of the phases present of the samples using electron probe X-ray microanalysis (EPMA). Standards supplied by Charles M Taylor Co. Stanford, CA were used in EPMA measurement. The phase analyses have been shown to be accurate within Ϯ1 wt%.Only metal cation contents were measured by EPMA; the oxygen content was added according to the assumed oxidation sate. All iron was calculated as FeO in the present work. However, it should be kept in mind that small amounts of Fe 3ϩ are always present in the sample, even in contact with metallic iron. Results and DiscussionTo consider the effects of Al 2 O 3 and Cr 2 O 3 on liquidus ISIJ International, Vol. 45 (2005) The experiments were carried out in the cristobalite and tridymite primary phase fields in the MgO-"FeO"-SiO 2 -Al 2 O 3 system in equilibrium with metallic iron. EPMA measurements of the phase compositions obtained in the present study are reported in Tables 1, 2 and 3. The data obtained have been used to construct liquidus isotherms in the MgO-"FeO"-SiO 2 -Al 2 O 3 system with 2, 3, and 5 wt% Al 2 O 3 (Figs. 1(a), 1(b), and 1(c)) at temperatures in the range 1 723 to 1 873 K. The liquidus surfaces on the limiting ternary systems of MgO-Al 2 O 3 -SiO 2 and "FeO"-Al 2 O 3 -SiO 2 were taken from Osborn and Muan.10,11) The general shape of the cristobalite/tridymite liquidus surfaces for the s...

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“…The idea of a Cr-rich immiscible liquid parent of the nodules (Shams, 1964) lacks supporting evidence for the existence of such liquidus compositions in the studied experimental systems. The system MgO-Cr203-SiO 2 (Keith, 1954) includes a prominent field of liquid immiscibility, but the high temperatures and the compositions for immiscibility are unlike those of natural magmas. The porphyritic nodular texture does not favour the liquid immiscibility mechanism for nodular chromitites because the nodule-forming and the matrix-forming parts are both chromite-rich, contrary to the Cr-rich and Cr-poor immiscible liquid fractions proposed so far for nodular textures.…”

Section: Z Ahmedmentioning

confidence: 99%

Porphyritic-nodular, nodular, and orbicular chrome ores from the Sakhakot-Qila complex Pakistan, and their chemical variations

Ahmed

1982

Mineral. mag.

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A new kind of chromitite texture—a porphyritic nodular texture, found in an alpine-type complex in Pakistan, is described. The chromite from phenocrystic nodules and that from their disseminated chromitite groundmass show comparable trivalent elements and postcumulus to subsolidus Mg−Fe2+ variations, which are also recorded from ‘normal’ nodular ore samples. The nodular ores differ from all other textural types of chromitite from this complex in an unusual, though slight, increase in Cr/(Cr+Al) with Mg/(Mg+Fe2+) between stratigraphically different desposits, which is caused by magmatic differences. The implications of major element variations in chromites and olivines of nodular chromirites are discussed and a cumulus origin is supported. Temperatures of final chromite-olivine equilibration ranged from 750 to 900 °C the individual nominal values being higher for chromitite with coarser chromite crystals and, or, higher chromite:silicate ratio.

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Phase Equilibria in the System MgO‐Cr²O³‐SiO₂

Cited by 80 publications

References 9 publications

Interactions between Exogenous Magnesia Inclusions with Endogenous Inclusions in a High Alloyed Steel Melt

Interactions between Exogenous Magnesia Inclusions with Endogenous Inclusions in a High Alloyed Steel Melt

Effect of Al2O3 and Cr2O3 on Liquidus Temperatures in the Cristobalite and Tridymite Primary Phase Fields of the MgO-"FeO"-SiO2 System in Equilibrium with Metallic Iron

Porphyritic-nodular, nodular, and orbicular chrome ores from the Sakhakot-Qila complex Pakistan, and their chemical variations

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