Magnesia Fire Bricks

Chemical Composition of Magnesia fire bricks

 

Magnesia fire bricks are alkaline refractory materials with magnesium oxide (MgO) as the main component and periclase as the main crystalline phase. They are classified into: ordinary magnesia fire bricks, direct-bonded magnesia fire bricks, magnesia-silica fire bricks, and magnesia-alumina fire bricks.

 

Physical Properties of Magnesia fire bricks

 

High refractoriness: Generally up to 2000℃ or higher.

Strong resistance to slag erosion: Strong resistance to alkaline slag, but poor resistance to acidic slag.

Load softening point: Generally 1500~1550℃, high-purity magnesia fire bricks can reach 1800℃.

Poor thermal shock resistance: Magnesia fire bricks have relatively poor thermal stability; however, increasing their purity can appropriately improve their thermal shock resistance.

High thermal conductivity: Second only to carbon fire bricks and silicon carbide fire bricks among refractory products, and it decreases with increasing temperature.

 

Applications of Magnesia fire bricks in Industry

 

Iron and Steel Metallurgy Industry

Oxygen Converter: A key material for converter linings, used in the furnace bottom, furnace walls, and furnace cap. Magnesia fire bricks can resist the scouring and erosion of high-temperature molten steel and alkaline slag inside the converter, while also withstanding sudden temperature changes during smelting, extending the converter’s service life.

Electric Arc Furnace: Used in areas such as the furnace bottom, furnace walls, and taphole, suitable for the high-temperature oxidizing environment of electric arc furnace steelmaking, resisting the erosion of molten steel and slag. especially suitable for the smelting of special steels.

Ladle and Tundish: Using high-purity magnesia fire bricks or magnesia-alumina bricks as linings, used for holding and transferring molten steel, reducing heat loss from the molten steel and preventing contamination of the molten steel by refractory materials.

 

Building Materials Industry

Cement Rotary Kiln: Used as a lining in the firing zone of a rotary kiln, where temperatures reach approximately 1700℃ and are subject to erosion by highly alkaline cement clinker melt. Magnesia bricks can withstand high temperatures and chemical erosion, ensuring stable operation of the rotary kiln.

Lime Kiln: Used as a lining in the high-temperature calcination zone to resist erosion by alkaline substances generated during lime calcination and adapt to the periodic temperature changes within the kiln.

 

Non-ferrous Metal Smelting Industry

Used as a lining in furnaces for non-ferrous metal smelting such as copper, nickel, lead, and zinc, including flash furnaces, reverberatory furnaces, and blast furnaces. It can resist erosion by non-ferrous metal melt and alkaline slag, and withstand the high temperatures and violent reaction environments during smelting.

 

Glass Industry

Used in the regenerator compartment of glass melting furnaces, and in certain parts of the melting pool. The high thermal conductivity of magnesia  bricks improves the heat exchange efficiency of the regenerator while resisting erosion by the alkaline atmosphere within the glass melting furnace.

 

When selecting a refractory material supplier, a comprehensive evaluation should be conducted based on core dimensions such as product compatibility, supply stability, technical strength, and service capabilities, while also taking into account the specific industry conditions and cost budget.