Magnesium Oxide( Caustic Calcined Magnesia) are made of the caustic calcined magnetite powder by machine pressing, with are a totally new kind of products applied to a rotary melting furnace sand making. The advantage of this new material is its high MgO content as well as burned substances, which can also avoid with-in-furnace decomposition burning so as to save much energy. By this new means, it will do a lot good for improving the rate of scrap steel and sand melting. It is used for converter steel making, through the splashing cross to protect the furnace, which can raise the furnace life.