Different applications and specifications of washed kaolin and calcined kaolin

Kaolin is a kind of non-metallic mineral. It is a kind of clay and clay rock dominated by kaolinite group clay minerals. Because of its white and delicate, also known as dolomite. It is named after Gaoling Village, Jingdezhen, Jiangxi Province.

Its pure kaolin is white, delicate, soft soil, with good plasticity and fire resistance and other physical and chemical properties. Its mineral composition is mainly composed of kaolinite, Eloite, hydromica, illite, montmorillonite, quartz, feldspar and other minerals.

Kaolin is divided into washed kaolin and calcined kaolin.

Difference between washed kaolin and calcined kaolin:

Firstly, the calcined kaolin is calcined, and the crystal type and original soil have changed. However, washing kaolin is only a physical treatment, which will not change the properties of the original soil.

Secondly, the difference in whiteness is relatively large, and the whiteness of kaolin will increase after light burning, while washing will not significantly increase the whiteness.

Third, different uses. Depending on the calcination temperature, kaolin can be used as a papermaking additive and refractory aggregate. The washed kaolin is generally used as papermaking filler.

At present, calcined kaolin mainly refers to hard kaolin (coal measures kaolin), the original soil is not adhesive, can not be directly used as raw materials for papermaking or refractory materials, need to be calcined after application; The original soil of washed kaolin has adhesive property and can be directly used as refractory binder or papermaking filler.

As far as paper fillers are concerned, the whiteness of calcined kaolin is much better, and the cost is relatively high.

Calcination will also lead to the increase of kaolin particle size, although the specific surface area is reduced, the adsorption is reduced, but the surface energy is reduced, so that the dispersion of kaolin is improved, and the structure is loose because of the non-normalization, which can also improve the dispersion. Calcined and dehydroxylated kaolin is usually refined by grinding or chemical surface modification as a reinforcing filler for rubber, plastics, etc., to partially replace white smoke.

Product use:

1. Washed kaolin has become a necessary mineral raw material for paper making, ceramics, chemicals, glue, adhesives, national defense and other industries;

Ceramic industry is the earliest application of kaolin, a large amount of industry. The general dosage is 20% ~ 30% of the formula. The role of kaolin in ceramics is to introduce Al2O3, which is conducive to the generation of mullite, improve its chemical stability and sintering strength, and decompose kaolin into mullite in the firing, forming the main frame of the strength of the billet, which can prevent the deformation of the product, make the firing temperature wider, and also make the billet have a certain whiteness. At the same time, kaolin has a certain plasticity, adhesion, suspension and bonding ability, giving porcelain mud, porcelain glaze good formability, so that ceramic mud is conducive to turning and grouting, easy to form.

2. Calcined kaolin is widely used in ceramics, rubber, plastics, coatings, artificial leather, self-cement, refractory materials, cosmetics and so on. With the further improvement of mineral processing technology, kaolin will be widely used. The coal geological system preparation unit can proceed from the actual situation and base on the kaolin resources and market demand in the coal measure strata. Kaolin is a common non-metallic mineral in nature, which was used in the past to produce ceramics, refractory materials and a small amount of additives in plastics and rubber.

Calcined kaolin has the characteristics of high whiteness, strong hiding power, good fluidity, high oil absorption and good suspension in coatings. The properties of the coating and coating film obtained by adding this fine calcined kaolin to the latex paint will make us feel that kaolin is not only a common filler, it can become a functional filler to improve the quality of the coating.

Calcined kaolin in rubber and special cable reinforcing agent, industrial plastic functional filler, ink filler.

Calcined kaolin can be used in paper coating to replace part of the expensive titanium dioxide.