Kaolin Castable Refractory Materials Argillaceous Heat Insulating Steel Smelting

Kaolin Heat-insulating castable Refractory Materials Iron and steel smelting

Product introduction  

Kaolin is a non-metallic mineral, which is a kind of clay and clay rock dominated by kaolinite clay minerals.
Its pure kaolin is white, fine and soft, with good plasticity, fire resistance and other physical and chemical properties. Its mineral composition is mainly composed of kaolinite, halloysite, hydromica, illite, montmorillonite, quartz, feldspar and other minerals. Kaolin is widely used, mainly in papermaking, ceramics and refractories, followed by coatings, rubber fillers, enamel glaze and white cement raw materials, and a small amount is used in plastic, paint, pigment, grinding wheel, pencil, daily cosmetics, soap, pesticide, medicine, textile, petroleum, chemical industry, building materials, national defense and other industrial departments.

Process characteristics
Whiteness brightness

Whiteness is one of the main parameters of kaolin process performance. Kaolin with high purity is white. Kaolin whiteness can be divided into natural whiteness and calcined whiteness. For ceramic raw materials, the whiteness after calcination is more important. The higher the whiteness, the better the quality. The ceramic process stipulates that drying at 105 ℃ is the classification standard of natural whiteness, and calcining at 1300 ℃ is the classification standard of calcined whiteness. Whiteness can be measured by whiteness meter. The whiteness meter is a device for measuring the reflectivity of light with a wavelength of 3800-7000 μ m (i.e. Angstrom, 1 angstrom = 0.1 nm). In the whiteness meter, the reflectance of the sample to be measured is compared with that of the standard sample (such as BaSO4, MgO, etc.), that is, the whiteness value (for example, whiteness 90 is equivalent to 90% of the reflectance of the standard sample).
Brightness is a process property similar to whiteness, equivalent to 4570 Ω; (angstrom) whiteness under wavelength light irradiation.
The color of kaolin is mainly related to its metal oxides or organic matter. Generally containing Fe2O3, it is rose red and brown yellow; Containing Fe2 +, light blue and light green; Containing MnO2, light brown; The organic matter is light yellow, gray, blue and black. The existence of these impurities reduces the natural whiteness of kaolin, in which iron and titanium minerals will also affect the calcination whiteness, resulting in color spots or melting scars on porcelain.
 

Particle size distribution

Particle size distribution refers to the proportion (expressed in percentage) of particles in natural kaolin in a given continuous range of different particle sizes (expressed in mm or micron mesh). The particle size distribution characteristics of kaolin are of great significance to ore washability and process application. Its particle size has a great impact on its plasticity, slurry viscosity, ion exchange capacity, molding performance, drying performance and sintering performance. Kaolin ores need technical processing. Whether it is easy to process to the fineness required by the process has become one of the standards to evaluate the ore quality. Various industrial departments have specific particle size and fineness requirements for kaolin for different purposes. For example, the requirements for kaolin used as coating in the United States are less than 2 μ The content of M accounts for 90-95%, and the papermaking filler is less than 2 μ M accounts for 78-80%.
 

Plasticity

The clay formed by the combination of kaolin and water can deform under the action of external force. After the external force is removed, it can still maintain the nature of this deformation, that is, plasticity. Plasticity is not only the basis of forming process of kaolin in ceramic body, but also the main process and technical index. Plasticity index and plasticity index are usually used to express the size of plasticity. Plasticity index refers to the liquid limit moisture content of kaolin clay minus the plastic limit moisture content, expressed as a percentage, that is, wplasticity index = 100 (W liquid limit - W plastic limit). The plasticity index represents the molding performance of kaolin clay. It can be obtained by directly measuring the load and deformation when the clay ball is crushed under pressure with a plasticity instrument. It is expressed in kg · cm. Often, the higher the plasticity index, the better the molding performance. The plasticity of kaolin can be divided into four levels.