High Temperature Thermal Insulation Calcined Alumina Magnesia Spinel Anti-peeling Refractory Castables

Calcined Magnesia Alumina Spinel Castable

Introduction:

Calcined Magnesia Alumina Spinel Castable (also called Calcined Magnesium Aluminate Spinel Castable), Refractory castables containing magnesia alumina spinel (MgAl₂O₄ or MgO?Al₂O₃) are materials for emerging technology in several applications, especial steel ladles of steelmaking field. The development of a self-forming spinel castable without any synthetic spinel grains appears to be promissory for optimum refractory linings.

The alumina magnesia “spinel-forming” castables have a low hot strength and consequently low erosion resistance. However, ladle sidewalls are less subject to erosion compared to the bottom, and the spinel-forming castables offer stress relaxation (elastic behavior), which helps the sidewalls avoid stress peaks and cracking.

The spinel family is a mineral group of oxides with a face-centered cubic crystal structure. The general formula is AB2O4, where A is a divalent metal ion (e.g., magnesium, iron, nickel, manganese, zinc) and B is a trivalent metal ion (e.g., aluminum, iron, chromium, manganese).

In the case of steel ladles, magnesium aluminate spinel is used due to its unique combination of properties, including high melting point, higher strength at elevated temperatures, high thermal shock resistance, excellent corrosion resistance, and low thermal expansion coefficient.

Optimal spinel content for spinel-containing and spinel-forming castables ranges between 15–30 wt.%, preferably 20–25 wt.%. A smaller amount of spinel leads to a higher corrosion rate, while a higher amount of spinel leads to a higher penetration rate because the spinel does not react with the infiltrated slag.

Magnesia Alumina spinel castable has excellent refractory properties, including high volume and thermal stability, good hot strength, and excellent resistance against corrosion, erosion, and thermal spalling. Excellent refractory properties have made it a preferred lining for steel ladles, reducing the erosion and corrosion of molten metal and slag and improving the ladle life and efficiency for decades. 

Physical & Technical Index

Characteristics

l  Good strength;

l  Good fluidity;

l  Appropriate solidification time; 

l  Save time, fast and convenient; 

l  High strength, long life, 

l  Good insulation properties; 

l  High temperature resistance, 

l  Corrosion resistance and good thermal shock resistance.

Applications:

l  Steel Ladle

l  Furnaces of metallurgy industry, heat treatment furnace.

l  Furnace of incineration of garbage, recirculating fluidized bed furnace.

l  Furnaces of chemical industry and construction industry.

l  Cement rotary kiln.

There are two types of alumina spinel castables used in the ladle.

·         Alumina magnesia castables are used in the ladle sidewall, and they form in-situ spinel. (I.e., the magnesia reacts with the alumina in the castable matrix at high temperatures to form spinel.)

·         Spinel-containing alumina castables are used in the bottom portion of the ladle, and they contain preformed spinel. (I.e., spinel is added directly as an aggregate in the castable composition.)

Packing:

l  Plastic bag(25kg), Kraft bag (25 kg), Plastic Ton bag(1 ton);

l  1 ton on pallet with plastic film & bundle belts.

l  Per your requests