Calcined kaolin originated in the United States, initially to remove the organic carbon value in soft kaolin and improve the whiteness of the product. Later, people used this method to process coal-measure kaolin, and produced products with performance, high-grade, and value far higher than ordinary kaolin. Greatly broaden the application range of kaolin. My country has abundant coal-measure kaolin resources, and calcination is an essential key process for coal-measure high soil.
The main purpose of kaolin calcination is to:
1. Remove organic carbon and other impurity minerals to improve whiteness.
2. Remove the water and hydroxyl groups of Kaolin to increase the void volume and chemical reactivity of the calcined product, improve the physical and chemical properties, and meet various application needs. The calcined kaolin is removed from the structure or crystal water, carbon and other volatile substances, and becomes kaolinite, the trade name is “calcined kaolin”.
Calcined kaolin has the advantages of high whiteness, small bulk density, large specific surface area and pore volume, good oil absorption, covering and abrasion resistance, and high insulation, weather resistance and stability.
1. The chemical composition is stable, the molar ratio of Si02/Al203 is 2/1.
2. The whiteness is pure and stable, the particle size is ultra-fine, and the distribution width and the sieve residue are low.
3. The flaky crystal shape is complete, the dispersion is good, the covering power is strong, and the floatability is good, and it is not easy to precipitate.
Uses of Calcined Kaolin
1. Calcined kaolin for coating
Scope of application: Various types of coatings, including latex paints, powder coatings, oil-based coatings and other fields.
Product features: high whiteness, fine particle size, chemical inertness, high covering ability, ideal fluidity and floatability, low cost, etc., which can reduce the need for expensive dyes; in addition to the above common characteristics, it also has It has the advantages of irregular shape, excellent optical properties, high oil absorption rate and pigment volume concentration, not easy to age, wear-resistant and easy to emulsify in water or oil medium, and has high hiding power. The most important thing is that it can replace the expensive titanium dioxide, and can reduce the photocoagulation phenomenon caused by the use of titanium dioxide when mixed and used; especially for the manufacture of latex-like pigments, it can make the coating have better opacity and corrosion resistance. Improve the hardness and quality of the coating film.
2. Calcined kaolin for rubber
Scope of application: all kinds of rubber products and plastic products and cable sheath, cable insulation layer and PVC, PE and other cable materials.
Product features: reasonable particle size distribution, pure texture, low impurity content, kaolin ten content greater than 98%, good dispersibility, fine particle size, good affinity with rubber and plastic, greatly improved in the processing of rubber and plastic. It has good chemical inertness and does not react with drugs or other chemical reagents at room temperature, thereby improving the corrosion resistance of cable products; high refractoriness can improve the thermal denaturation temperature of cable products; Excellent electrical insulation properties, etc.
3. Calcined kaolin for ceramics
Scope of application: high and low voltage electric ceramics, daily-use ceramics, building sanitary ceramics, chemical corrosion-resistant ceramics and glazes for arts and crafts.
Product features: high whiteness, high chemical purity, high refractoriness, good dispersibility and fluidity, and high predictability The shape can be arbitrarily changed without cracks, and the shape can still be kept intact after removing the external force, and it has good forming, drying and sintering properties. The fired products have the characteristics of white color, compactness, high mechanical strength and high yield.
Post time: Jun-21-2022