Today, in the industrial sector, kaolin is widely used in dozens of industries such as paper, ceramics, rubber, chemicals, coatings, pharmaceuticals and national defense. The whiteness and brightness of kaolin will directly affect its quality, what are the factors that affect the whiteness of kaolin?

Definition of whiteness:

Whiteness is the degree to which the surface of a substance is white, expressed as a percentage of the white content. The whiteness is 90%, which is equivalent to 90% of the reflectivity of the standard sample. This index is an important reference quality indicator for papermaking, paint, and industry.

Raymond mill

Factors affecting kaolin whiteness:

Usually, the content of vanadium, chromium, copper, manganese etc in kaolin is small, and has little effect on whiteness. The mineral composition and content of iron and titanium are the main factors affecting the whiteness of kaolin. The forms of iron ore include pyrite, limonite, hematite, rutile, chlorite and so on. Their existence not only affects the natural whiteness of kaolin, but also affects the whiteness of calcination, which makes the pigmentation and melting of porcelain different.

The iron impurities in kaolin not only affect the color of ceramic products after calcination, but also seriously affect the dielectric properties and chemical stability of ceramics. Therefore, the removal of iron impurities in kaolin plays an extremely important role in the use of kaolin.

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1st Aug 2018