Magnesia Bricks Specification Magnesia Brick Middle Grade Magnesia Brick High Purity Magnesia Brick Electrical Fused Magnesite Brick MZ-89 MZ-91 MZ-95 MZ-96 MZ-97 MZ-98 DMZ-98 MgO % e 89 91 94.5 95.5 96.5 97.5 97.5 CaO % d 3 3 2.5 2 1.5 1.0 1.0 Apparent Porosity d 20 18 18 18 18 18 18 Cold Crushing Strength e 49 58.8 60 60 60 60 40 Initial Soften Point Under Load e 1540 1550 1620 1650 1680 1700 1700 Permanent Linear Change on Reheating -0.6 -0.5