Experimental Establishment of the CaAl₂O₄–MgO and CaAl₄O₇–MgO Isoplethal Sections within the Al₂O₃–MgO–CaO Ternary System

Abstract

The isoplethal sections CaAl 2 O 4 -MgO and CaAl 4 O 7 -MgO of the Al 2 O 3 -MgO-CaO ternary system have been experimentally established at 1 bar total pressure and air of normal humidity. The sections obtained provide new data and information that are in disagreement with thermodynamic evaluations and optimizations of the Al 2 O 3 -MgO-CaO ternary system published to date. These differences arise mainly from the inclusion, or exclusion, of the binary compound Ca 12 Al 14 O 33 , mayenite, as a stable phase in the reported studies of the system. The presence or absence of this compound within the system has an important impact on the solid state and melting relationships of the whole ternary system. The present study confirms the solid-state compatibility CaAl 2 O 4 -MgO and CaAl 2 O 4 -MgO-MgAl 2 O 4 up to 13721721C, the peritectic melting point of the later mentioned subsystem.

Los diagramas de equilibrio de fases como una herramienta para el diseño y comprensión del comportamiento en servicio de los materiales refractarios

“…Los datos correspondientes a esta región del sistema no habían sido determinados previamente. En consecuencia, el sistema tuvo que ser estudiado [44,45,46,47], previamente al desarrollo del material, y los resultados se exponen en la Figura 12.…”

“…Para ello se recurrirá nuevamente al sistema ternario: Al 2 O 3 -CaO-MgO [45,46,47] 2 , dolomita, y Al 2 O 3 en el rango de composiciones del segmento "a-b", según se indica en la Figura 16 [55].…”

“…De lo contrario se podrá incurrir en graves errores a la hora de predecir o estudiar el comportamiento de los materiales y/o a la hora de introducir mejoras o diseñar nuevos materiales. [45,46,47,24]. La figura ilustra el procedimiento desarrollado para obtener nuevos Cementos de Aluminatos Cálcicos (CAC) conteniendo MgAl 2 O 4 por reacción de MgCa(CO 3 ) 2 y Al 2 O 3 [18,55].…”

Structural studies on Ca3Al4MgO10 (C3A2M)—A ternary phase in the system CaO–Al2O3–MgO

“…However, during recent years the ternary system has seen a revival of interest due to applications in the fields of slag research for secondary refining processes in metallurgy, refractories or as host materials for luminescence applications . Aside from experimental studies, thermodynamic assessments using the Calphad technique have also been employed . Although, as pointed out by Hallstedt, the computational results have to be treated with care as long as there is a lack of data on solid‐phase relations.…”

Thermodynamic Assessment of the System CaO–P2O5: Application of the Ionic Two‐Sublattice Model to Glass‐Forming Melts

“…Various approaches for modeling the chemical thermodynamic behavior of liquid phases have been developed and successfully used in thermodynamic assessments of complex oxide systems 7–14 . The principal models used to describe the liquid phase in these systems are the ionic two‐sublattice model, 15 the modified quasichemical model, 16 and the modified associate species model 17 .…”