This product is made by grinding high-quality low silicon high calcium ore (SIO2 ≥ 0.5%) and calcining it in a rotary kiln at 1750 ° C. It is used as raw material to produce magnesium dry ramming material, which is not limited by furnace size and can be applied to various specifications of high-power electric furnaces (HP), ultra-high power (VHP), steel alloys and other low slope furnaces.