Dependence of the properties of aluminazirconiasilica refractories on the type of aggregate and the amount of zirconia and silica additives

JSC “URIR named after A. S. Berezhnoy” has developed the vibrocasting of refractories and manufactures high­quality competitive products, including high­refractory crucibles of various compositions for induction melting of heat­resistant alloys and steels. The most widespread among them are high alumina crucibles, which use fused corundum or corundum and mullite powders as a filler and α­form alumina as a fine­dispersed binder. Based on their composition, alumina­zirconia­silica refractories (AZS) with a content of 10 % ZrO2, which have a filler in the form of fused corundum and mullite, and a fine­dispersed binder — α­form alumina and zircon, were developed. The influence of aggregate type and zircon and silica additives amount on the properties of vibrocast alumina­zirconia­silica (AZS) refractories with a content of 10—22 % ZrO2 was studied. The possibility of complete replacement of fused corundum and mullite with tabular alumina in the granular component of the batch, and with alumina, zircon and quartz sand in the fine component in the manufacture of vibrocast AZS refractories with a content of 10 % ZrO2 or with alumina and zircon in the manufacture of vibrocast AZS refractories with a content of 16—22 % ZrO2 was established. The highest values of properties are observed in alumina­zirconia­silica samples with a content of 10 % ZrO2, which contain tabular alumina (55 %), alumina (22 %), zircon (16 %) and quartz sand (7 %), namely: apparent density 3.05 g/cm3, open porosity 15.6 %, cold crushing strength 195 N/mm2, thermal shock resistance (1300 ºС — water) > 20 heat changes. Based on the research results, the technology of vibro­cast alumina­zirconia­silica refractories was improved and the raw material base for manufacturing products was expanded.