| 摘要 |
1,154,878. Magnesium oxide refractories. KAISER ALUMINUM & CHEMICAL CORP. 10 Oct., 1966 [11 Oct., 1965], No. 45127/66. Heading C1A. A fired refractory shape comprises directly bonded periclase particles and not more than 1-5% of impurities disposed in discrete discontinuous zones, the shape containng at least 98-5% magnesium oxide, and one or both of (1) silica in an amount of not more than 0'75% and (2) CaO in an amount at least equal in weight to the amount of any silica present. Preferably the periclase particles are in euhedral form and are substantially free of matrix film, and the CaO: 5i0 2 weight ratio is at least 1-86: 1; the silica being present in an amount of less than 0À5%. The refractories are preferably made by preparing a batch corresponding to the above weight proportions, firing this in the form of a compacted shape to at least 1400‹ C. and crushing to provide the periclase of predetermined size. This mixture is then mixed with 0À5-1À5% of a bonding agent such as lignin sulphonate, dextrin or molasses and 2-3À5% water, pressed and fired at at least 1500‹ C. to bond the periclase crystals to each other. |
