Optimizing the compositions of refractory cements produced using the waste of chemical industry

Abstract

The article presents the results of optimization of the quantitative compositions of cobalt-containing calcium-aluminate and barium-aluminate special cements prepared from chemical industry wastes. Based on the obtained experimental data, the coefficients of the polynomial were computed which express the dependence of the ultimate compression strength and the melting temperature on the quantitative ratio of the CaAl2O4, CaAl4O7, and CoAl2O4 phases for calcium-aluminate cement and the quantitative ratio of the ВaAl2O4, ВaAl12O19, CoAl2O4 phases for barium-aluminate cement. The "composition–property" diagrams and the projections of the lines of the same level were plotted for the ultimate compressive strength and the melting temperature of the obtained cements. The following promising areas were selected for the CaO–CoO–Al2O3 system (wt.%): 25–55 CaAl2O4, 15–35 CaAl4O7, and 25–45 CoAl2O4; and for the ВaO–CoO–Al2O3 system (wt.%): 60–20 ВaAl2O4, 10–20 ВaAl12O19, 30–60 CoAl2O4. The main physical-mechanical properties of the developed cements of optimal composition are the following: the fineness of grinding is characterized by the total passage through the sieve No 006; for calcium cements: water-cement ratio of 0.2, the setting time: the initial set of 1 h 10 min, and the final set of 5 h 40 min; the ultimate compression strength after hardening of 28 days of 63 MPa; the for barium cements: water-cement ratio of 0.16; the setting time: the initial set of 1 h 50 min, and the final set of 5 h 00 min; the ultimate compression strength after hardening of 28 days of 66 MPa; and the calculated mass absorption coefficient =175 cm2/g. The refractoriness is 16300C and 17500C for calcium cement and barium cement, respectively.