Kaolin Ore Dressing And Purification Process

The kaolin purification process mainly includes gravity separation, scrubbing iron removal, and magnetic separation processes to purify and remove impurities from kaolin. However, chemical treatment and flocculation methods are sometimes needed to process kaolin further. The kaolin purification process is mainly used to separate non-clay minerals and organic matter such as quartz, feldspar, mica, iron minerals, titanium minerals in kaolin, and produce kaolin products that can meet the needs of various industrial fields.

Kaolin is a non-metallic mineral, a clay and clay rock mainly composed of kaolinite clay minerals, with good physical and chemical properties such as plasticity and refractoriness. Its mineral composition mainly comprises kaolinite, halloysite, hydromica, illite, montmorillonite, quartz, feldspar, and other minerals.

Kaolin ore dressing and purification process

1. Grading desludging purification method

Kaolin washing and classification desludging are carried out before separation. The main purpose is to remove most of the quartz, mica, feldspar coarse sand, etc. Therefore, it is necessary to water-select and grade kaolin by using a spiral sand washing machine, hydrocyclone, dewatering screen, and other equipment before selection, and the effect is more obvious.

2. Magnetic separation

Kaolin ore contains a small amount of iron minerals, which can be removed by magnetic separation based on the magnetic difference between gangue minerals such as hematite pyrrhotite, and kaolin.

3. Chemical treatment

Common chemical treatment and purification methods for kaolin include chemical leaching, chemical bleaching, and roasting purification.

A.Chemical leaching

Impurities in kaolin can be selectively dissolved by leaching agents such as sulfuric acid, hydrochloric acid, and nitric acid. This method is mainly used for iron reduction and purification of low-grade kaolin, such as removing hematite, limonite, and siderite.

B.Roasting purification method

Impurities such as iron-containing impurities, carbon-containing impurities, sulfides, etc. in kaolin can be removed by magnetic roasting, high-temperature roasting or chlorination roasting by utilizing the differences in chemical composition and reaction activity between the impurities and kaolin.

4. Selective flocculation

By adding flocculants, impurities such as fine-grained quartz, pyrite, alunite can be selectively separated. Commonly used flocculants are sodium hexametaphosphate, ammonium polyacrylamide, and water glass.

5. Flotation

Flotation mainly utilizes the physical and chemical differences between gangue minerals and the surface of kaolin to treat kaolin ore with more impurities and lower whiteness, and remove its iron, titanium, and carbon impurities. Commonly used flotation methods include ultrafine flotation and double-liquid layer flotation.