Yuan lei's little knowledge | the difference between calcined and washed kaolin

Release time:

2024-01-29 09:34

Kaolin is a non-metallic mineral, which is a kind of clay and clay rock mainly composed of kaolinite clay minerals. Because it is white and delicate, also known as white earth. Kaolin can be divided into calcined kaolin and washed kaolin. What is the difference between the two? Let's take a look at the following.

calcined kaolin

Calcined kaolin is to sinter kaolin in a calciner to a certain temperature and time, so that its physical and chemical properties have a certain change to meet certain requirements.

Application range: used in papermaking, coating can replace some expensive titanium dioxide. Can also be used for paint, water-based latex coatings; rubber and special cable reinforcing agent, industrial plastic functional filler, ink, food, medicine, cosmetics filler; and advanced porcelain and special ceramic raw materials.



Washed Kaolin

It is mainly composed of igneous rocks, hydrogenic rocks and other parent rocks in the rock through natural weatherization. It is a light gray to light yellow powder, and the particles are hexagonal flake crystals. Slightly soluble in hydrochloric acid or acetic acid at room temperature.

It has the advantages of good crystallization, high purity, fine particle size, moderate oil absorption, strong covering rate and good dispersion. It is easy to disperse in rubber compound, easy to process, smooth surface of rubber compound, and is conducive to the dispersion of carbon black in rubber compound when combined with carbon black.

Application range: used in high-grade paint, coating, ink, rubber, plastic, wire, cable, etc.




1. Washed kaolin is only physically treated and will not change the nature of the original soil. Calcined kaolin is calcined, and the crystal form and original soil have been changed.

2, whiteness difference is relatively large, generally after light burning kaolin whiteness will increase, and washing will not increase the whiteness.

3, different uses. According to different calcination temperatures, kaolin can be used as a papermaking additive and refractory aggregate. The washed kaolin is generally used as a papermaking filler.

4. Calcined kaolin currently mainly refers to hard kaolin (coal series kaolin). The original soil has no cohesiveness and cannot be directly used as raw materials for papermaking or refractory materials. It needs to be calcined and applied after calcination. The original soil of washed kaolin has cohesiveness and can be directly used as refractory binder or papermaking filler. As a papermaking filler, the whiteness of calcined kaolin is much better, and the cost is also relatively high.

Kaolin, calcined, washed, paper, filler, as, refractory, application, coating

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