Refractory materials based on compounds of Mg, Zr, Si and Ca

Basic refractory materials modified with zirconium oxide or calcium zirconate find application in metallurgy and ceramic industry. Fundamental raw material for ZrO2 production is zirconia sand, while synthetic calcium zirconate is produced in reaction of zirconium oxide with calcium oxide. Regarding these facts new highly refractory composite materials CZ and DZ were obtained from mixtures of zirconia sand and limestone of dolomite. These composite materials may contain stabilised ZrO2 and/or calcium zirconate. Among other important components are periclase and calcium orthosilicates. All these phases have high melting points (above 2000 oC). This work describes thermal and technological properties and microstructure of CZ and DZ materials. The use of calcareous raw materials (limestone and dolomite) yields materials with good hydration resistance. These composites may be used as an additive modifying properties of magnesia products. (author)