Patent ID: 7459409

Claim:
Unshaped refractories consisting essentially of: fine particles having a diameter less than 0.75mm; and, aggregate mixed into the fine particles having a diameter between 0.75mm and 10mm; wherein the fine particles have MgO content between 10 mass % and 35 mass % of the entire amount of the fine particles, wherein the fine particles have Al 2 O 3 and MgO content as sum total mass %, being between 90% and 100% of the entire amount of the fine particles, wherein the fine particles consist essentially of particles made of 0.5-10 mass % of alumina cement based on the total mass of the unshared refractories and periclase-spinel as a mineral-phase in a raw material used as a source of MgO containing 40-8 0 mass % of MgO and the main remainder of Al 2 O 3, to total mass 100% of the raw material used as the source of MgO, and wherein content of the particle of the periclase-spinel is between 5 mass % and 40 mass, to 100% of the whole amount of the unshaped refractories, and wherein the aggregate consists essentially of at least one particle selected from the group consisting of alumina and spinel.