What is magnesia zirconium brick?

Magnesia zirconium brick is a magnesia composite refractory material made of magnesia and zircon as the main raw materials. The main chemical components are MgO, ZrO2 and SiO2. The main mineral composition is periclase, olivine and baddeleyite.


During the sintering process, zircon in the matrix reacts with coarse-grained magnesia to generate forsterite and baddeleyite (ZrO2) wrapped around the magnesia particles to protect the magnesia particles from erosion. Due to the difference in thermal expansion between periclase and ZrO2, fine cracks are formed inside the brick, which can disperse stress. Therefore, magnesia-zirconium bricks have good thermal shock stability and good corrosion resistance to metal oxides and sulfides.

Magnesia zirconium bricks are mainly used in the upper and middle parts of the regenerator lattice of glass kilns, and their service life is much higher than that of fired magnesia bricks. The service life of soda lime glass kilns can reach more than 6 years.

Erosion Mechanism Analysis of Magnesia-Zirconium Bricks Used in Glass Kiln Regenerator


Most domestic glass kiln regenerators use three-layer magnesia-zirconium lattice bricks for the upper part. The bricks are fired in ultra-high temperature tunnel kilns and are a new type of periclase; forsterite; . Magnesia zirconia bricks have produced a large amount of stable forsterite and zirconia before use, and are closely surrounded by periclase. Due to the strong erosion resistance of forsterite and zirconia, the erosion resistance of the brick is improved. The temperature of the upper part of the regenerator is about 1300°C, and the magnesia-zirconium brick can completely resist the impact of high temperature at this temperature. With the exchange of airflow in the regenerator, a large amount of silicon, sodium, calcium and a large amount of sulfur and a small amount of phosphorus in the molten pool glass fly material adhere to the surface of the brick, gradually invade the interior of the brick, and form sodium, calcium and magnesium. The sulfates, phosphates and silicates and their complex salts disintegrate the bond strength of the bricks, resulting in a decrease in the strength of the bricks. 

1. Corrosion of silica

The erosion of magnesia zirconium brick is between periclase and zircon. With the increase of SiO2 content, the ratio of CaO/SiO2 changes, and a new low melting point silicate phase is formed, such as diopside (CMS2), magnesia rose pyroxene (C3MS2), calcium forsterite (CMS), etc. The formation of these silicate phases leads to a large volume effect, which makes magnesia zirconium bricks crack and peel off. 


2. Erosion of sulfur and alkali vapor

When the glass furnace is used, a large amount of harmful oxide gases such as sulfur and phosphorus are generated after the fuel is burned. At the same time, a certain amount of alkali is added as a flux when producing glass products. These substances are exchanged in the regenerator. It adheres to the surface of magnesia-zirconium brick, penetrates into the interior of the brick, deposits in the pores of the brick and on the periclase surface, and reacts to generate new salts - magnesium sulfate, anhydrous Glauber's salt (Na2SO4). Change the structure of the brick and destroy the microstructure of the brick, thereby reducing the service life of the brick.

Zhengzhou Shennan Refractory Co.,Ltd are professional in producing high quality magnesia zirconium bricks ,any demands of this brick,please don't hesitate contact with me. 


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