| 摘要 |
<p>A fused basic refractory grain consists essentially of magnesia, calcia, silica and R2O3 materials (Cr2O3, Fe2O3 and Al2O3) in th proportions by weight on the basis of an oxide analysis of not more than 1% SiO2, not more than 1% R2O3 materials, sufficient CaO to give a CaO:SiO2 ratio of from 3: 1 to 4.5: 1, the balance being MgO; the MgO being present predominantly as periclase crystals with the SiO2 and CaO present predominantly as discontinuous deposits along crystal edges and as lenticular pools within the crystals of periclase. A fired, ceramically-bonded basic refractory shape may be made from a batch comprising a grain as above by pressing the batch to form a shape and firing to form a ceramic bond throughout the shape. The batch may consist entirely of the fused basic refractory grain or may additionally contain dead-burned magnesite, dead-burned dolomite, lime or chrome ore. The fused grain may constitute a fine (- 65 mesh, Tyler Scale) fraction of the batch and the magnesite, dolomite, lime or chrome are a coarse (+65 mesh) fraction. The fired, ceramically bonded shape may be impregnated with a non-aqueous, cokable carbonaceous material.</p> |
