Do you know what the common raw materials of high-quality magnesium bricks are?

Anyone who has some knowledge of refractory materials knows that the main raw materials of magnesia refractory bricks are magnesite, sintered magnesia and fused magnesia. Today, Tianyang Refractories will focus on the knowledge of fused magnesia, and hope to help everyone.

 

High-quality magnesite or light-burned magnesium powder is melted in an electric arc furnace at a high temperature above 2800 ° C, and the product obtained after being cooled and then crushed is fused magnesite. The strength, corrosion resistance and chemical stability of fused magnesia are all It is better than sintered magnesia and its purity varies according to the purity of the raw materials. In magnesia or magnesia carbon refractory materials, more and more fused magnesia is replacing sintered magnesia. The raw materials are naturally cooled after melting in the electric arc furnace, and the periclase crystallizes and grows from the melt. After cooling, the under-melt on the block is removed, and the under-melt can be returned to the electric arc furnace for high-temperature melting. When magnesite or magnesite is used to produce fused magnesia, a large amount of gas is discharged, resulting in crystallization and density.

Fused magnesia is mainly brown-yellow and black-brown granular blocks with good uniformity. The main mineral is periclase. Fused magnesite has very few impurities, low silicate content and island-like distribution. The periclase is crystallized from the melt, the crystals are coarse, the direct contact between the grains is high, the structure is very dense, the high temperature volume and chemical stability are good, and the hydration and slag resistance are good. In an oxidizing atmosphere, it can maintain stability below 2300 ° C, so that the good performance of periclase can be fully exerted. Colorless and transparent large-grained periclase can be obtained by smelting with a special process. Large grain magnesia has the following excellent properties and uses:

 

①Large crystalline magnesia has good crystallization, stable lattice constant, high purity, and few defects. It can be used for superconductors, printed boards with strong insulating material films, and substrate materials for far-infrared sensor receivers.

 

② The refractory made of large fused magnesia is used in special parts with strong corrosiveness in the metal melting furnace, which improves the service life of the melting furnace.

 

The grain size of periclase in sintered magnesia is 60-200 μm, while the grain size of periclase in fused magnesite is 200-400 μm, and the large-crystal fused magnesite reaches 700-1500 μm, or even more than 5000 μm.