Kaolin is a nonmetallic mineral, a type of clay and claystone dominated by kaolinite group clay minerals. It is also known as dolomite because it is white and delicate. The pure kaolin is white, delicate and soft, with good physical and chemical properties such as plasticity and fire resistance. Its mineral composition mainly consists of kaolinite, eclogite, mica, illite, montmorillonite, quartz, feldspar and other minerals. Kaolin has a wide range of uses, mainly used in paper, ceramics and refractory materials, followed by paints, rubber fillers, enamel glaze and white cement raw materials, a small amount of plastics, paints, pigments, abrasive wheels, pencils, cosmetics, soaps, pesticides, pharmaceuticals, textiles, petroleum, chemical industry, building materials, national defense and other industrial sectors.

1. Construction materials kaolin is also widely used in cementitious materials, by kaolin through the appropriate temperature for calcination, ultrafine pulverization and other processes to be prepared and obtained by the kaolin is considered to be a new generation of cement and concrete in the admixture, they are for the workability, strength and durability of the cementitious materials have obvious enhancement and alleviation of the role of the cementitious materials, at the same time they are for the high-performance cementitious materials generally appear in the At the same time, they also have a good inhibition of the phenomenon of self-shrinkage and shedding that commonly occurs in high-performance cement-based materials.

2. The ceramic industry kaolin in the ceramic industry in the early application of time, the amount is also large, usually can account for 20 ~ 30%. Kaolin can increase the content of Al2O3 in ceramics, and the process of mullite generation is easier, thus improving the sintering strength and stability of ceramics [8]. When firing ceramics, kaolin decomposition of mullite is the process of forming the framework of the billet, this process makes the ceramic billet is not easy to go deformation, at the same time, make the firing temperature range wider, and improve the whiteness of ceramics. At the same time, kaolin itself has the plasticity, bonding, suspension, bonding and other characteristics, so that the porcelain clay porcelain glaze molding improved, more conducive to billet turning, grouting, ceramic molding and other processes.

3. Refractory industry kaolin has good refractory, commonly used in the production of refractory materials, products can withstand the load at high temperatures without deformation. Kaolin as the main component of kaolinite, as well as bentonite and bauxite, etc., according to its use of high temperature resistance, collectively referred to as refractory clay. Certain colored kaolin can not be used for ceramics and paper making, but is a good raw material for refractory materials. Kaolin used as refractory products are mainly two types: refractory bricks, silica-aluminum fiber cotton. The former refractoriness is not less than 1730 ℃, according to the need to make a variety of sizes and shapes of refractory bricks. The latter is a lightweight refractory insulation materials, kaolin in the 1000 ~ 1100 ℃ roasting, and then 2000 ℃ electric arc furnace will melt the ore, blown under the high-speed airflow made of cotton.

4. Plastics kaolin application in the plastics industry is mainly used as filler. As the calcined kaolin has a large adsorption area and activity, it is applied to plastics, can be adsorbed in the plastic conductive ions, thus improving the performance of plastics, so that the plastic is more flat, beautiful, chemical corrosion resistance ability to enhance. In the plastics industry, calcined kaolin can replace titanium dioxide and used as pigment, calcined kaolin in plastics to replace more than 20% of titanium dioxide, the optical properties of plastics are not significantly reduced. Kaolin added to plastic films can also reduce the influence of infrared rays, the insulation strength of plastics will be improved after adding calcined kaolin. Modified kaolin can also be used in PE agricultural film, it can improve the temperature of the greenhouse at night, so that the light is more uniform, and promote the insulation effect of agricultural film.

5. Paint industry kaolin because of its white color, low price, good fluidity, chemical stability, surface cation exchange, has long been used as a filler for paints and coatings. Kaolin can be used to improve the paintability, coating system storage stability, coating of moisture resistance and impact resistance and other mechanical properties, pigment color and bloom resistance. With the development of production, the performance and durability of coatings and other aspects of the increasingly stringent requirements, such as the preparation of low VOC, high solid coatings, thinner and flawless smooth, bright film, at this time, the need to use kaolin as an additive. Kaolin can be adapted to almost all coating systems, from primer to topcoat, all solid components, film thickness and gloss.

6. The rubber industry kaolin filled into the rubber colloidal mixture, can enhance the chemical stability of rubber, abrasion resistance and mechanical strength, to extend the hardening time, but also to improve the rheology of rubber, mixing, vulcanization, improve the consistency of the unvulcanized products, to prevent it from denting, collapsing soft, sagging, deformation, flat tube, and so on. The properties of kaolin rubber products such as waterproof, permeability, fire resistance, chemical activity have also been greatly improved. At the same time, kaolin can also be used as a filler in rubber, which can significantly reduce the cost without affecting the rubber properties.

7. The cable industry to produce high insulation performance cable needs to be added in excess of the electrical properties of the improver. Kaolin as the only product that can be made into an electrical performance improver, the prospects are naturally favorable. In the requirement of high electrical insulation properties of plastic cables and insulation materials, need to add modified calcined kaolin. Kaolin calcined by the appropriate temperature has a very high electrical resistivity, different calcination temperature kaolin void rate is not the same, the void of the cable material in some of the more active harmful components have a certain adsorption effect, can improve the cable insulation; calcined kaolin and then surface modification, can improve its dispersion in polymer materials, enhance the performance of the products can be in the organic polymer materials - modifiers - between calcined kaolin Produce a good bonding interface, so that calcined kaolin in the cable can be evenly dispersed, play a better role as a bridge.

8. Environmental protection materials, environmental protection materials is also one of the applications of kaolin, kaolin can be used as synthetic molecular sieve, polymerized aluminum chloride. In addition, due to the high content of aluminum elements in kaolin makes it the main raw material for the production of polymerized aluminum chloride, polymerized aluminum chloride is a new type of purification agent, the process is simple, has a good flocculation effect, the price is low, the residual aluminum content in the water after treatment is relatively low, it can generate flocs with high density, fast settling speed, low corrosive properties to the equipment, etc., it has been widely used in purification of drinking water and Industrial wastewater treatment. The use of kaolin to produce polymerized aluminum chloride can improve the quality of the corresponding products, while also reducing the production cost, little pollution to the environment, economic and social benefits. Modified kaolin also has a relatively high matrix activity, strong resistance to heavy metal pollution, good catalytic activity and selective adsorption properties, so in the process of preparing a variety of catalysts modified kaolin becomes an important filler.

9. Paper industry kaolin clay in the paper industry in the amount of far more than other industries. Kaolin clay particle size is small, stripped with good scales and flake form, the ratio of flake diameter and thickness is large, chemically stable, so it is used as a paper making filler and paper coating to improve the gloss of paper, fill the gaps between paper fibers, improve opacity and so on. Used as filler, in improving the performance of paper at the same time can also reduce costs; used as a coating material, you can improve the paper's permeability to ink, inclusiveness and the appearance of paper. In papermaking the main requirements of kaolin is the particle size and impurity content, the requirements of particle size less than 2μm, whiteness greater than 86%.