With low silicon, high calcium and high purity Fused magnesia And large crystal fused magnesia as the main raw material, together with large scale high-purity graphite, metal and boride as well as other composite fillers, combined with thermosetting and thermoplastic phenolic resin. The product has the characteristics of high density, high strength, high purity, good resistance to mechanical scouring of molten steel, high temperature resistance and oxidation resistance. Fused magnesia