Pure kaolin has high whiteness, soft, easily dispersed suspension in the water, good plasticity and high adhesion, excellent electrical insulation properties; with good acid-soluble, low cation exchange capacity, better fire resistance and other physical and chemical properties. Therefore kaolin is widely used in papermaking, ceramics, rubber, chemicals, paints, pharmaceuticals and defense industries, ect. Kaolin has wide application in the paper industry. There are two main areas, one is filler in paper making process, and the other is pigment in used in coating industry.
Kaolin processing production process
By using calcinations processing,kaolin whiteness can reach 90 to 95, powder size is around 4,500 to 6,000 mesh. Final product has high whiteness, ultra-fine powder size, mainly used for paper, high-grade paint and other industrial fields.
Beneficiation, crushing, grind into powder of 325 mesh or less
Mixing powder, water and disperser,and beating,make it into 4500-6000mesh
The ultra fine slurry was dried and beat,then calcinated , adding 1-3% white agents of the total weight when calcinated, White agents is made by coal, sodium sulfate and sodium chloride, by weight 10:0.3:0.2 mix. Calcination temperature should be 970-990 ℃
Beating and packed in bags
To meet ultrafine powder demand in the paper, plastics and rubber products industry, we need to increase fineness of kaolin, then improve the quality of the product. Ultrafine grinding process are grinding, high pressure extrusion, jet milling method.In kaolin project,MTW Euro-type Trapezium mill and SCM ultrafine grinding mill are very popular.
MTW mill is used in grinding and processing of metallurgy, building plastics, fillers, cosmetics, chemicals and other industries......
SCM mill is widely used in paint, paper, paint, rubber, fillers, cosmetics, chemicals and other industries.
Currently, the global kaolin output is about 40 million tons (a simple sum of the data belongs yield countries, none of which trade statistics ore, perhaps containing more double counting), which high quality grade is about 23.5 million tons. The paper industry is the largest consumer of high quality kaolin, about 60% of the total consumption of kaolin. According to data provided by the company Temanex Consulting Canada, in 2000 the global paper and paperboard output is about 319 million tons, kaolin consumption in paper coating is about 13.6 million tons. For common paper, kaolin as filler is around 10-20% weight in paper making. For coated paper and paperboard (including lightweight coated paper, coated paper and coated paperboard), in addition to filler, it still need to kaolin for paint, pigments in paper making, and the weight is around 20-35%. Kaolin used in paper making, it not only can give a good performance and good coating coverage luster performance, but also increase the whiteness of the paper, opacity, smoothness and printability, greatly improving the quality of the paper.