The caustic calcined magnesite is made from calcined magnesite powder through Mixing, pressing spheroid.It is used for converter steel making, through the splashing cross to protect the furnace, which can raise the furnace life. MQ-70 MgO 70% MIN. SiO2 5.00% MAX. CaO 3.00% MAX. LOI 23% MAX. MQ-67 MgO 67% MIN. SiO2 5.00% MAX. CaO 3.00% MAX. LOI25% MAX. MQ -65 MgO 60-65% SiO2 6.00% MAX. CaO 3.00% MAX. LOI 30% MAX. The size is 10-40mm