Kaolin mineral processing method and process

Quartz, feldspar, mica, iron minerals, titanium minerals and other non-clay minerals and organic matter in the separated kaolin, produced to meet various needs in the area of industrial kaolin products, in addition to re-election, flotation, magnetic separation of kaolin In addition to purification, the kaolin is sometimes treated by deep processing methods such as chemical bleaching, ultrafine stripping, calcination, and surface modification.

First, hydraulic classification

Hydraulic classification includes spiral classification (separation +1 mm coarse sand), sedimentation tank classification (separation + 0.053 mm fine sand), hydrocyclone classification (separation - 0.053 mm fine sand), centrifugal classifier or small diameter hydrocyclone classification ( For ultra-fine particle size classification of 0.002 ~ 0.010mm).

Second, high gradient magnetic separation

The magnetic field strength of 1 600 kA/m or more is generated by the magnetic magnetic medium to remove Fe2O3 and TiO2 in the kaolin, and the papermaking paint and the advanced ceramic raw material are produced.

Third, selective flocculation

By adding a flocculant, impurities such as fine-grained quartz, pyrite, and alumite are selectively separated to produce a knife-coated grade kaolin. Common flocculant hexametaphosphate, sodium phosphate, ammonium polyacrylamide, water glass.

Fourth, chemical bleaching

Adding bleaching agent such as insurance powder to reduce the high-valent iron of limonite and hematite in kaolin to soluble ferrous iron, or adding oxidizing agent to oxidize pyrite and dyeing impurities to improve the whiteness of kaolin.

Five, stripping

In the stripping machine, a fine medium ball is stirred to produce a grinding and stripping action, and the kaolin aggregate particles are separated into thin crystals to produce a blade-coated grade kaolin having a particle size of less than 2 μm and a content of 90% or more.

Sixth, calcination

When calcined at 800～1 000°C, the kaolin loses water, the phase transforms, and some impurities volatilize, which improves the whiteness and insulation of the kaolin, and produces cables and rubber plastic fillers. Calcination is a coal-based processing methods (hard) kaolin necessary.

Seven, surface modification

The kaolin is coated with a coupling agent or the like to increase the amount of the kaolin added to the plastic rubber, and is used for treating a kaolin filler for rubber plastics.

Eight, the process

The ore processing of kaolin is divided into two processes: dry process and wet process.

The dry method generally breaks the mined ore produced by the crusher to about 25 mm and feeds it into the cage crusher to reduce the particle size to about 6 mm. The hot air blown into the cage crusher reduces the moisture of the kaolin to about 10% from about 20% at the time of production. The crushed ore is further ground by a blown Raymond mill equipped with a centrifugal separator and a cyclone. The process can remove most of the sand and is suitable for processing ore with high whiteness, low sandstone content and suitable particle size distribution. Dry processing costs are low, and products are often used in low-cost fillers in industries such as rubber, plastics and paper.

The wet processing process includes several stages of dispersing, grading, impurity sorting and product processing of the mud. The general principle process is: raw ore → crushing → slurry → sand removal → cyclone classification → stripping → centrifuge classification → magnetic separation (or bleaching) → concentration → pressure filtration → drying → ceramic grade or paper coating grade products.