DEVELOPMENT OF HOT STRENGTH IN SYNTHETIC MAGNESIA REFRACTORIES HAVING HIGH B{11 O CONTENT

摘要

A magnesia refractory shape possessing good strength properties at elevated temperatures is prepared from a magnesia grain containing 90 to 99% MgO, and over 0.1% by weight B2O3; and which can have a Ca-Si mole ratio of less than 2.0. Fine particles of an alkali metal-containing compound are added to the magnesia grain to help volatilize the boron during firing. Fine particles of calcium-and silicon-containing material can be admixed, if needed, with the magnesia grain to increase the Ca-Si mole ratio of the fine (-100 mesh) particles of the admixture to above 2:1 and to increase the total weight percent of CaO and SiO2 present in the fine particle component of the composition to between 3 to 7% by weight.