The role of intermediate magnesia as refractory

Medium-grade magnesite in the steelmaking production system including converter, electric furnace, outside refining furnace, ladle and tundish equipment, in the electric furnace, dry vibration material, prefabricated or cast-in-place furnace cover or using the cover: triangle area, etc., have a good fire-resistant use effect; In converter and electric furnace, the damage of the general use of refractory spray coating for appropriate repair, the method has by hand, wet, dry or flame spraying and slag splashing furnace protection method. In the converter, the traditional slag splashing technology is generally adopted, and the furnace life can reach more than ten thousand times. There are many kinds of furnace, RH method and DH method degidation device inserted into the corresponding tube liner, generally with high aluminum refractory castable large area cast into the whole, service life is about 20~80 times. Ladle and tundish are important auxiliary industrial equipment of steelmaking furnace and thermal equipment which consume more refractory materials.

The iron system includes sintering, coking and blast furnace and its auxiliary equipment. Belt sintering machine point furnace with refractory plastic and clay combined with refractory castable site production, or with phosphate refractory castable prefabricated block hoisting, its service life is 3~6 years. When the line ignition device is used, the top pressure is more, the working condition of the furnace becomes better, the light and high strength refractory castable or refractory fiber and its products can be used as lining, and the better effect is also obtained.

Promotion of sintering: The promotion of sintering by metal on refractory materials can be attributed to two factors: first, the introduction of plastic phase forming by metal can improve the density of the green body, shorten the distance between particles, and reduce the energy required by mass diffusion in the firing process; Secondly, the melting point of metal is generally lower than that of refractory materials, and the liquid phase can be formed at a lower temperature. The capillary force formed by the liquid phase and its viscous flow accelerate the migration rate of atoms and the contraction of the green body, and promote the densification process of sintering.

Plastic phase forming: the metal crystal lattice will slip under the action of stress, which has plastic characteristics and is introduced into the refractory material. Compared with the hard inorganic material particles, the plastic forming characteristics will be played in the forming process, making the density of green blank prepared under the same forming pressure higher than that without metal sample added.

Improvement of toughness: Metal can improve the toughness of composite materials by means of crack bridging, crack deflection and crack barrier, among which crack bridging is an effective toughening mechanism.