Refractory smear (also known as paint) is a mud paste-like material used as a working lining or protective lining on the surface of a refractory lining. Its solid/liquid mass ratio or volume ratio is similar to that of refractory mud. It is a kind of Bingham-type fluid mud with small yield value. It has good spreadability and can be constructed by manual painting (brush) or mechanical spraying method. .
Generally, the refractory coatings used in high temperature kilns use phosphate or low cement as binders, but these binding methods must be used under specific conditions of use due to the performance of the binder, and there are corresponding shortcomings. The refractory smear with phosphate as binder has good bonding performance. It can be used to coat the side wall and top of the kiln. However, according to the use conditions (such as air temperature), a certain coagulant should be added to adjust the hardening during construction. For example, if cement is used as a coagulant, it needs more than 16 hours of curing to harden, and it has to be baked at more than 500 ℃ to have good performance. If the baking temperature is lower than 450°C, the phosphate-bonded refractory may be damaged because the orthophosphate bond phase is not formed. If the temperature is too high (such as 1000°C), the phosphate-bonded refractory may be damaged by the aluminum phosphate and calcium phosphate bond phases. softening and loss of wear resistance.
Spreads with low cement as binder have poor adhesion and slow hardening. Using cement as a binder requires at least 24 hours of curing to harden. Due to its poor adhesion, it is difficult to coat the side walls of the kiln, and it cannot be used for the top coating.
The fast-hardening wear-resistant refractory coating material is composed of brown corundum, electric ceramic material, high alumina bauxite, alumina micropowder, silica micropowder, calcium aluminate cement, heat-resistant steel fiber and chemical additives. It has good construction performance and hardening speed. It has the characteristics of fast speed and excellent wear resistance, which can meet many requirements such as rapid construction, emergency maintenance, wear resistance and wear of kiln pipes and related equipment.
The quick-hardening wear-resistant refractory coating is based on brown corundum as the main aggregate. Because of its high hardness and wear resistance, it is supplemented by the toughening effect of heat-resistant steel fibers, which effectively improves the anti-stripping performance of the material, so that the The wear resistance and erosion resistance of the material surface are significantly improved.
The quick-hardening wear-resistant refractory smear is made of calcium aluminate cement plus polyacrylic acid latex as a composite binder. During construction, polyacrylic acid latex is used to obtain excellent adhesion (Wax-based Binders). The smear can not only coat the side walls, but also the top is extremely convenient. . During curing, the reaction of Ca++ released by cement hydration and COOH groups in polyacrylic acid latex is used to cross-link the polyacrylic acid polymer and obtain strength quickly (about 7 hours). When the temperature is raised, CaO from cement, AL203 and SiO2 in silica powder react to form anorthite CaO. A1203.2Sio2 is combined with ceramic to obtain medium temperature strength.
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