What is the good or bad of kaolin to distinguish? What is its criterion?What percentage does it contain and what element does it contain?
Kaolin is a kind of soft clay mineral and two non clay mineral, which are mainly composed of kaolinite and sub group minerals. Kaolinite minerals are mainly composed of small tabular or tubular kaolinite minerals of less than 2 m, Al4 [Si4O10] (OH) 8. Because of its hydrous aluminosilicate chemical composition, layered structure and particle size, it has many special properties which are not available in general minerals. The extensive use of kaolin is inseparable from its excellent physical properties. Pure kaolin with high whiteness, soft and easy to disperse suspended in water, refractoriness physicochemical performance, good plasticity and high adhesion, excellent electrical insulation properties and the acid solution, good low cation exchange capacity, high.
Whiteness is one of the main parameters of kaolin's technological properties. Kaolin with high purity is white. Kaolin whiteness, natural whiteness, and whiteness after calcination.The color of kaolin is mainly related to its metal oxides or organic matter. Containing Fe2O3 was rose red, brown and yellow; containing Fe2+ was pale blue, pale green with pale brown; 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 whiteness of the calcined, porcelain stains or scars appear.
Pure kaolin with high whiteness, soft, easy to disperse in water, suspended in plasticity and good adhesion, high excellent electrical insulation properties; has good acid soluble cationic, low resistance and other physical and chemical properties, better exchange. Therefore, kaolin has become the necessary mineral material for dozens of industries, such as paper making, ceramics, rubber, chemicals, coatings, pharmaceuticals and national defense. There are reports that Japan has also used kaolin instead of steel, cutting tools, lathes, drills, and internal combustion engines. Especially in recent years, the rapid development of modern science and technology, the application of kaolin is more extensive, began extensive use of kaolin as new materials in some high-tech fields, and even nuclear reactor space aircraft and spacecraft components with high temperature porcelain, made of kaolin.
