Effect of redox conditions on the evaporation of oxide melts in the CaO-MgO-FeO-Al2O3-SiO2 system

Abstract

Physicochemical studies of cosmic substance provide a basis for fundamental concepts of the origin, composition, and structure of planets and meteorites. Of great importance in this context is the experimental study of the properties of oxides and melts in the CaO – MgO – FeO – Al 2 O 3 – SiO 2 system, which is the basic system of meteoritic substance and, in particular, the hightemperature substance of white inclusions (CAI). There is extensive evidence for the significant influence of changes in temperature and pressure on this substance during its formation and evolution. The investigation of its evaporation and condensation is of special interest because of the combination of high-temperature and cooling stages during its evolution. Data on CAI evaporation and condensation, which are required for calculations, can be obtained experimentally. The most efficient approach is a combination of the Knudsen effusion technique with the mass-spectrometric analysis of evaporation products [1‐3]. This study is aimed at determining the influence of redox conditions on oxide melt evaporation by the example of melts in the CaO – MgO – FeO – Al 2 O 3 – SiO 2 system. Note that the evaporation of such multicomponent oxide melts is dominated by the evaporation reactions of simple oxides, because the content of complex gaseous oxide compounds in the vapor is insignificant [3]. Therefore, the evaporation of these melts can be described to a first approximation by the evaporation tendencies of simple oxides.