Dependence of the structural and rheological characteristics of vibrocasting alumina­chromia castable and the properties of samples from it on the active alumina additive

Abstract

The influence of additives amount (1—5 %) of two dispersed a­form active alumina with practically the same chemical composition but with different dispersion (specific surface area of 3.0 and 5.0 m2/g) on the moisture content of vibrocasting coarse­grained low­cement alumina­chromia castable mass (masses without the mentioned additives and with 1—5 % additive), on the strength of its structure 30, 60 and 90 minutes after the mass preparation and the effect on main properties of vibrocast castable samples from it (masses with an addition of 5 % of the mentioned alumina) both the unfired (cold crushing strength after hardening in humid conditions for 1; 3; 7 days) and fired at a temperature of 1580 °C ones (open porosity, apparent density, cold crushing strength) was studied. It was established that an increase in the amount of both active alumina and an increase in their dispersion leads to a gradual natural tendency to reduce the moisture content of masses while improving their flowing compared to the mass without the addition of dispersed active alumina; obtaining high strength of the mass structure, and higher with the addition of more dispersed alumina; improving the properties of unfired castable compared to castable without the addition of dispersed active alumina. More dispersed alumina was more effective both in reducing the moisture content of castable and improving its properties. The practicality of introducing dispersed active alumina of one of the studied grades into castable was shown.
 Based on the research results, an improved technology for manufacturing by vibrocasting castable products from low­cement alumina­chromia castable mass containing an active alumina additive was developed. This technology ensures the production of unfired and fired products with improved properties. The technical documentation was developed and the raw material base for the production of low­cement alumina­chromia castable was expanded.