The quality is a burnt magnesia spinel brick made from fused magnesia, low iron sintered magnesia and fused hercynite.This synthetic hercynite is a patent by RHI Refractories.

• 它由电熔镁砂、低铁烧结镁砂和电熔铁铝尖晶石制成的烧结镁铁尖晶石砖，这种人工合成的铁铝尖晶石是RHI奥镁公司的专利。