... husbandry, papermaking, production of pharmaceuticals, rubber making, and building material industry etc. Application:Fire-proof material, refractory, magnesium oxide bricks, MgO board, abrasive ... , fertiliaer, water retention material, feed additive, paper making, etc. Specification: Mgo ≥SiO2 ≤CaO ≤Fe2O3 ≤ ...