COMPOSITION FOR ALUMINA SPINEL-BASED CAST REFRACTORY

PURPOSE:To obtain the composition which is a composition, containing an alumina-based aggregate, a spinel and an alumina cement, capable of filling a narrow space without any vibration and having the thermal volume stability for a long period by blending a magnesia aggregate with specific alumina particles and the alumina cement in a specific proportion. CONSTITUTION:This refractory composition is obtained by using a burnt alumina clinker, etc., as an alumina-based aggregate and a burnt spinel clinker (blended in an amount of 3-20%), etc., as a spinel and blending the resultant composition with 1-18wt.% magnesial aggregate, 2-15wt.% alumina particles having =73wt.% Al2O3 content and >=5500cm /g Blaine value and further powder of CaO or Ca(OH)2 in an amount of 0.02-0.15wt.% expressed in terms of CaO. Furthermore, the flow value of body prepared by mixing the obtained composition with water in an amount of 6wt.% expressed in terms of outer percentage is >=185mm when the body is cast into a cement flow cone defined by the specification of JIS R-5201 and the flow cone is then taken out to allow the body to stand for 30sec without vibration.