What's the requirement of high-grade kaolin?
Whiteness is one of the main parameters of kaolin's technological properties. Kaolin with high purity is white. Kaolin whiteness, natural whiteness, and degree of self calcination. For ceramic raw materials, the whiteness after burning is more important. The higher the calcination whiteness, the better the quality. The ceramic process stipulates that the drying temperature is 105 degrees centigrade and the classification standard is the natural whiteness. The calcined 1300 DEG C is the grading standard for the whiteness of the calcined products. Whiteness can be measured by a whiteness meter. A whiteness meter is a device for measuring the reflectivity of light at 3800 7000A wavelengths. In the whiteness meter, the reflectance of the sample to be measured is compared with that of the standard sample, that is, the self - value.
Brightness is a process characteristic similar to that of self, which is equivalent to the degree of self - illumination under the 4570A wavelength.The color of kaolin is mainly related to its metal oxides or organic matter. Containing Fe2O2 was rose red, brown and yellow; Fe2+ is light blue, light green, light brown with MnO2; organic matter tends to yellow, gray, green, black and other colors. The presence of these impurities, reduced the natural whiteness of kaolin, in which iron and titanium minerals will also affect the degree of calcination, porcelain stains or scars appear.
Kaolin is mainly aluminosilicate, the main component of AL2 (Si2O5) (OH) 4, or written as Al2O3 2H2O 2SiO2,Some trace metal elements which may be a different color, the specific color and the metal or metal oxide flame color color.
