Raymond mill processing kaolin

• Publication time：2025-07-09
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What is kaolin?

Kaolin is a natural clay mineral with kaolinite as the main component, and its chemical formula is Al₂Si₂O₅(OH)₄. It was first discovered in Gaoling Mountain, Jingdezhen, Jiangxi Province, China.

Physical properties

Color: Usually white or light gray, and can be yellow, brown, pink, etc. when containing impurities.

Texture: Fine, soft, and easily dispersed in water.

Plasticity: Medium, with a low shrinkage rate after drying.

Refractoriness: The melting point is about 1750°C, and it has excellent high - temperature resistance.

Chemical properties

The main component is aluminum silicate, containing a small amount of oxides such as iron, titanium, calcium, and magnesium.

It is weakly acidic or neutral (pH 6 - 7) and has stable chemical properties.

Applications of kaolin processed by Raymond mill

80 - 200 mesh: Provides support for ceramic bodies, resists high temperatures in refractory materials, and enhances the physical properties of rubber.

200 - 325 mesh: Gives paper a fine texture, enhances the covering power of paint, and serves as a pesticide carrier to improve the use effect.

325 - 400 mesh: Used in cosmetics, ensures the efficacy of drugs in medicine, and ensures the insulation performance in cables.

Process of kaolin processed by Raymond mill

Impurity removal: Wash with water and use magnetic separation to remove impurities such as iron and quartz to improve whiteness.

Drying: The moisture content of the raw material should be less than 5%. For raw materials processed by the wet method, they need to be dried first. When the moisture content of the raw material is high, a rotary dryer or flash dryer can be used for pre - drying.

Feed particle size: Generally, it is required to be ≤20mm. If it is too large, it needs to be pre - crushed with a jaw crusher first.

Grinding: The raw material is fed into the mill by a feeder, and a shovel scoops it up and sends it between the grinding roller and the grinding ring. The grinding roller crushes the material into small particles under the action of centrifugal force. Impurities such as quartz in kaolin will wear the grinding roller and the grinding ring, shortening the service life of the equipment. It is recommended to select high - chromium alloy as the material of the grinding roller and the grinding ring. The pressure of the grinding roller is generally between 0.8 - 1.2MPa. The greater the pressure, the stronger the crushing force, but it will accelerate the wear of the grinding roller and the grinding ring.

Classification: The classification system accurately screens the powder through a rotating classification impeller. Qualified fine powder (80 - 400 mesh) is discharged, and the coarse powder falls back for re - grinding. The higher the fineness, the lower the output. For fineness above 400 mesh, ultra - fine processing is required.

Post - treatment stage: Kaolin for special purposes needs post - treatment. For example, fillers for rubber and plastics need surface modification, and cable - grade kaolin needs to be calcined first and then ground.

Precautions for kaolin processed by Raymond mill

Coarse powder: Check the rotation speed of the classifier, adjust the motor frequency or the transmission ratio of the pulley, adjust the air volume of the fan, control the opening of the damper, or replace the fan.

Abnormal vibration: Check whether the bearing of the grinding roller is damaged and replace it in time; ensure that the feed particle size is uniform and fully pre - treat the raw material.

Equipment selection: For small and medium - sized production, choose the 4R - type Raymond mill, which is equipped with 4 grinding rollers. The fineness of the finished product is 80 - 325 mesh, the production capacity is 1 - 6t/h, it has a small footprint, low investment cost, and is convenient for operation and maintenance.

High - whiteness requirements: A magnetic separator can be equipped to remove iron impurities, and ceramic grinding rollers can be selected as the material of the grinding roller to reduce iron pollution.

Summary

The Raymond mill can process kaolin into products with different finenesses from 80 - 400 mesh. During processing, attention should be paid to links such as impurity removal, drying, and post - treatment. Equipment selection needs to consider requirements such as production capacity and maintain key components.

Click on the picture to learn about the details of the CRRM Raymond Mill