ALUMINA CEMENT, ALUMINA CEMENT COMPOSITION AND PREPARED UNSHAPED REFRACTORY USING THE SAME

摘要

PROBLEM TO BE SOLVED: To obtain an alumina cement having excellent CO gas resistance never shown in the conventional articles and excellent in volume stability and resistance against the change of color tone of a hardened body in the case of exposing the hardened boy for a long period by controlling the contents of Fe and FeO in the alumina cement to be lower than a specific value. SOLUTION: The alumina cement contains <=0.1wt.% each of Fe and FeO as chemical components. An alumina cement composition improved in fire resistance and sintering property at a high temp. is formed by blending α-Al2 O3 with the alumina cement. A prepared unshaped refractory is formed by blending a refractory aggregate with the alumina cement or the alumina cement composition. As a method to reduce the content of Fe and FeO in the alumina cement, for example, a method of using a CaO raw material or an Al2 O3 raw material small in iron content and a method of melting in a carbon lining furnace at the time of producing a clinker by a melting method in an electric furnace or the like are mentioned.