... and well-cativeness, are widely used in chemical industry, animal husbandry, papermaking, production of pharmaceuticals, rubber making, and building material industry etc ... , magnesium oxide bricks, MgO board, abrasive, fertiliaer, water retention material, feed additive, paper making, etc. Specification: Mgo ≥SiO2 ≤CaO ≤Fe2O3 ≤Al2O3≤L.O ...