Description of the chemical interaction in the system CaO-Al2O3-SiO2

Abstract

In this study the construction of a phase tree and the description of the chemical interaction for the ternary oxide system CaO-Al2 O3 -SiO2 are given. Particular interest to a system consisting of oxides of calcium, aluminum and silicon is associated with the production of highly demanded functional materials with desired properties. Melts of the CaO-Al2 O3 -SiO2 system are of great theoretical and applied importance. This is due to the signifi cant role of melts of these oxides and their mixtures in metallurgy, ceramics production, and other industries. Phase relationships in the system with the complete disappearance of liquid in the CaO-Al2 O3 -SiO2 system has made it possible to construct a phase tree of the system, which includes a linear part and two cycles. The construction of the phase tree is given taking into account the formation of four double compounds in the CaO-SiO2 system, fi ve double compounds in the CaO-Al2 O3 system, one double compound in the Al2 O3 -SiO2 system, and two ternary compounds. The stable complex includes fi fteen secondary phase triangles, interconnected by sixteen stable secants. For mixtures corresponding to equivalence points (points of intersection of unstable and stable secants), the chemical interaction is described in accordance with the law of equivalents. It is concluded that for all mixtures corresponding to equivalence points, interactions are thermodynamically possible under standard conditions. The prediction of crystallizing phases is made.

Keywords

• ternary system
• phases tree
• сrystallizing phases
• stable secants
• unstable secants
• chemical interaction
• calcium oxide
• aluminum oxide
• silicon oxide
• metathesis reaction