At present, kaolin has become an indispensable mineral material in the ceramics, papermaking, rubber, refractory and chemical industries. So how should we choose the direction of kaolin deep processing?
Kaolin is an important non-metallic mineral resource and a typical 1:1 type layered silicate mineral. Pure kaolin has high whiteness, soft texture, easy dispersion and suspension in water, good plasticity, high adhesion, and excellent electrical insulation properties. It has good acid solubility, very low cation exchange capacity, good fire resistance and other physical and chemical properties.
Kaolin deep processing direction 1: beneficiation and purification
The biggest feature of kaolin mineral processing technology is that it depends on the type of ore. In practical applications, it is difficult to obtain high-quality kaolin products using a single purification process, especially when processing low-grade coal-based kaolin with large reserves in my country and kaolin with complex ore composition.
1. Less impurities: adopt simple methods such as drying, crushing and air classification.
2. Many impurities: Generally, gravity separation (sand removal), strong magnetic separator or high gradient magnetic separator and superconducting magnetic separator are used after dispersion and pulping. Magnetic separation (removal of iron and titanium minerals), chemical bleaching (removal of Ferrous minerals and reducing ferric iron to ferrous iron), flotation (separating from aluminum-containing minerals such as alunite or removing anatase) and other methods.
3. Organic impurities: In addition to the above-mentioned methods, methods such as screening (except for plant fibers) and calcination (except for organic peat and coal) after beating should also be used.
Kaolin deep processing direction two: ultrafine crushing
There are two types of ultrafine crushing processing of kaolin: dry method and wet method. The dry method is mostly used for ultra-fine grinding of hard kaolin or kaolinite. The product fineness is generally d90≤10μm. Most of the processing equipment uses mechanical impact ultra-fine mills, ball mills, Raymond mills, vertical mills, etc. In order to control product particle size distribution, especially the content of the largest particles, fine classification equipment is often required. The wet method is mostly used for ultra-fine crushing of soft kaolin and sandy kaolin after sand removal and impurity removal. It is especially used for processing papermaking pigments and coating grade kaolin products with d80≤2μm or d90≤2μm. It is also used in industry for hard The ultra-fine crushing method must be used to process kaolin or kaolinite coating-grade kaolin products with d80≤2μm or d90≤2μm.
Kaolin deep processing direction three: modification process
1. Calcination modification: Calcination can remove carbon and improve whiteness. It is an essential process for mineral processing and a special processing method to improve the properties of kaolin. Calcined kaolin has the characteristics of high whiteness, small bulk density, large specific surface area and pore volume, good oil absorption, covering and wear resistance, high insulation and thermal stability.
2. Intercalation/peeling: Intercalation/peeling refers to destroying the interlayer hydrogen bonds of kaolin through mechanical and physical effects, chemical reactions, or a combination of the two, expanding the interlayer spacing, and ultimately achieving separation between layers. Obtain a structural monolayer to achieve a method of increasing the activity and specific surface area of kaolin clay. There are many intercalation methods, but no matter which method is used to intercalate kaolin, it is inseparable from the use of intercalation agents. It also needs to be realized by combining external mechanical force, microwave, ultrasonic waves, calcination and other conditions.
3. Coating modification: Coating modification is divided into two methods: metal oxide and organic coating. Commonly used surface modifiers mainly include silane coupling agents, silicone (oil) or silicone resin, surfactants, organic acids and organic amines. It is worth mentioning that calcined kaolin modified by titanium dioxide surface coating in metal oxides is widely recognized by the market in applications that replace titanium dioxide.
The deep processing project of kaolin ore cannot be separated from the help of grinding equipment. The grinding process is the basis of kaolin deep processing. Raymond mill, vertical mill, ultra-fine vertical mill, ring roller mill and other equipment produced by Guilin Hongcheng can process 80-2500 mesh kaolin ultra-fine powder, and the output can meet the processing needs of different scales. If you have kaolin deep processing needs, welcome Leave us a message for device details.