Classification of magnesia refractories
①Alkaline magnesium dry ramming material is widely used in various induction electric furnace linings and ultra-high power electric furnace bottoms. In recent years, it has been used on continuous cast steel intermediate steel drums, and the effect is also good. Dry ramming material is a kind of monolithic refractory without liquid binder and water. After construction, there is no need to undergo strict maintenance. The hot surface of the dry ramming material is sintered into a whole by baking or heating of the high-temperature melt during use, forming a dense working layer with a certain strength. Outside the layer, the remaining dry materials are still unsintered tightly packed structure, so it has good heat insulation performance, while avoiding the cracking and perforation caused by the stress caused by expansion and contraction of the refractory during use, and it is also convenient to remove. But dry ramming material is not suitable for use in kilns with rotation and height of the furnace.
②Magnesium paint or gunning material
Magnesium and magnesium-calcium materials are good for purifying molten steel, so they are widely used in continuous cast steel intermediate steel drums. However, when this coating or gunning material is used for casting low-phosphorus steel, the use of phosphate binders should be avoided. Secondly, because the paint has added a lot of water, it is necessary to bake at high temperature to remove the water, so as not to add hydrogen to the first few barrels of molten steel.
③ Magnesium castable
Magnesium-based carbon-containing castables, because water does not wet the graphite and the density of graphite is low, so that the development of magnesium-based carbon-containing castables is affected. The use of surfactants to change the hydrophobic surface of graphite to hydrophilic may be a solution to the problem. An important way for carbon refractory castables. In addition, the carbon-containing refractories used in steel plants are also high-quality raw materials for making magnesia carbon-containing castables, because the particles or powders made from such residual bricks have high carbon content, uniform C distribution, and compactness.