Product description:

Calcining modification is to heat the kaolin through physical methods to remove part or all of the hydroxyl groups on the surface to obtain special physical and chemical properties. For example, calcining the kaolin at an appropriate temperature to make all the hydroxyl groups in the structure When the new stable phase (mullite, cristobalite, etc.) has not been formed, the amount of dissolution of silicon and aluminum is the largest, and kaolin has great activity.

Calcining can also change the crystal structure of kaolin (mainly caused by the breaking of the hydrogen bond between the layers and the removal of crystal water), from the original ordered lamellar crystal structure of kaolin to disordered structure of metakaolin, making the original crystal Part of the groups in the inner layer are exposed, and due to the removal of crystal water, the types and numbers of surface active points increase (the types change from -OH to Si-O, Al-O and part of the remaining -OH), so Its reactivity increases.

Calcining can also increase the particle size of kaolin. Although the specific surface area is reduced and the adsorptive property is reduced, the surface energy is reduced, which improves the dispersibility of kaolin, and the amorphization makes the structure loose, which can also improve the dispersibility. The calcined and dehydroxylated kaolin is usually used as a reinforcing filler for rubber, plastics, etc. after being ground and refined or chemically modified to partially replace white smoke. Shvarzman et al. found that when the amorphous phase in kaolin exceeds 55%, it can be used as an active filler according to the ASTM618 standard.

Compared with uncalcined kaolin, calcined kaolin has a lower bound water content, an increase in silica and alumina content, an increase in active points, a change in structure, and a smaller and uniform particle size. It is filled with uncalcined kaolin. Compared with the NR compound, the vulcanization characteristic curve of the low-temperature calcined kaolin filled NR compound is basically the same. The hardness of Sauer A type is unchanged, and the tensile strength is improved. The physical properties of both meet the requirements of the non-transparent sole industry standard of sports shoes.

Product process:

（1）Process flow:The production process of ultrafine calcined kaolin mainly includes four parts:

（2）(1) Pre-drying of raw materials to meet the moisture requirements for ultra-fine pulverization;

（3）(2) Superfine pulverization and classification of kaolin to reach the particle size required by Chemicalbook calcination;

（4）(3) High temperature calcination process to the required purity and whiteness;

（5）After calcination, it disintegrates and disaggregates to reach the required fineness of the final product. The production process flow chart is as follows: paint coating, plastic rubber grade: