Calculation and evaluation of temperatures and eutectic compositions of multicomponent sections of the CaO—Al2O3—Fe2O3—Cr2O3 system

Abstract

The predicted service temperatures and eutectic compositions of the polycomponent sections of the CaO—Al2O3—Fe2O3—Cr2O3 system were calculated and evaluated. According to the results of geometrical topological studies of this system, the CaAl2O4—CaFe2O4—CaCr2O4—Ca4Al2Fe2O10 tetrahedron has the largest relative volume and the smallest degree of asymmetry. However, the composition of this tetrahedron includes two compounds that do not have hydraulic activity; this will adversely affect the cement strength. Presence of CaFe2O4 will significantly reduce the composition melting point, that why the CaAl2O4—Ca12Al7O33—CaCr2O4—Ca4Al2F2O10 tetrahedron is of more interest. The calculations result of temperatures and eutectic compositions of triple and tetra-component sections of the CaAl2O4—Ca12Al7O33—CaCr2O4—Ca4Al2F2O10 region of the CaO—Al2O3—Fe2O3—Cr2O3 system are presented. The phases that make up this tetrahedron are highly likely to exist in the CaO—Al2O3—Fe2O3—Cr2O3 system, which will allow us to develop a stable technology for the oil-well cementing materials based on calcium-ferro-alumina chromate cement without special techniques for ensuring high accuracy of the starting components dosage. The paper presents graphic images of the liquidus surface of polycomponent sections of optimal region of system. Selected areas are the most suitable for producing oil-well binding materials with an elevated temperature in application. It was found that, composite materials based on this system can be used at temperatures above 1350 °C. Based on the analysis of temperatures and eutectics compositions of polycomponent section, the use of rational area compositions for producing high-temperature resisting oil-well cement has been proved.