Thermodynamic aspects of synthesis of refractories from talc-kaolin-alumina compositions

Possible solid-phase chemical reactions with talc, kaolinite, and alumina taken as the initial raw components are considered from the standpoint of thermodynamics. Stoichiometric dependences that make it possible to control the phase composition of the synthesized materials by varying the proportion of the ingredients are analyzed. The reaction resulting in a three-phase combination of corundum—mullite—cordierite with stoichiometric coefficients of 45, 74, and 6, respectively, is shown to have the maximum thermodynamic probability. It is assumed that the point that corresponds to this proportion of the phases in the M—A—S phase diagram is a singular point and can be close to the assumed point of the triple eutectic in the A—MA—A3S2 elementary triangle.