Plastic refractory mass contg. alumina and chromic oxide - has high strength and resists attack by molten metal and slags

摘要

The mass has a ratio of aggregate (a): matrix (b) of ca.2:1 the aggregate (a) being mainly fused alumina, whereas the matrix (b) is mainly materials with specific surface min. 0.1m2/g. The mass contains min. 80 wt.% Al2O3+Cr2O3, the Cr2O3 being present in the matrix (b) and forming a solid soln. contg. a trigonal phase during baking. To improve the working life and plasticity, and to suppress the formation of a spinel on baking, the mass has a min. content of MgO, iron oxides, and alkali metal oxides. The refractory has high resistance to repeated corrosive-and erosive- attack by molten metals and thier acid-, semi-basic- and basic slags; high vol. stability; high abrasion resistance; and low apparent density. The mass pref. contains 30-90% Al2O3, the matrix contg. Cr2O3 particles with specific surface (SS) 0.4m2/g. Used as monolithic structures or mouldings in the metallurgical industry.