YuanLei little knowledge | The difference between calcined and washed kaolin

Kaolin is a kind of nonmetallic mineral, which is a kind of clay and claystone mainly composed of Kaolinite clay minerals. Because it is white and delicate, also known as dolomite. Kaolin can be divided into calcined kaolin and washed kaolin, so what is the difference between the two, the following Xiaobian show you.

Calcined kaolin

Calcined kaolin is to sintering kaolin in calcination furnace to a certain temperature and time, so that its physical and chemical properties have a certain change, in order to meet certain requirements.

Application: Used in papermaking, coating can replace part of 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, cosmetic filler; And high-grade porcelain and special ceramic raw materials.

Wash kaolin with water

It is mainly composed of igneous rock, igneous rock and other parent rocks decomposed by natural weathering. It is a light gray to light yellow powder with 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 cover rate, good dispersion and so on. It is easy to disperse in the rubber, easy to process, smooth surface of the rubber, and the carbon black is conducive to the dispersion of carbon black in the rubber.

Application: high grade paint, paint, ink, rubber, plastic, wire, cable, etc.

The difference between

1. Washing kaolin is only a physical treatment, which will not change the nature of the original soil; While calcined kaolin is calcined, the crystal type and the original soil have changed.
2. The whiteness difference is relatively large. Generally, after light burning, the whiteness of kaolin will increase, while washing will not increase the whiteness.
3. Different uses. Depending on different calcination temperature, kaolin can be used as papermaking additive and refractory aggregate. And washed kaolin is generally used as papermaking filler.
4. Calcined kaolin at present mainly refers to hard kaolin (coal measure kaolin), the original soil is not adhesive, can not be directly used as a raw material for papermaking or refractory materials, need to be calcined after application; The original soil of washed kaolin has adhesive property and can be used directly as refractory binder or papermaking filler. As a papermaking filler, the whiteness of calcined kaolin is much better and the cost is relatively high.