The processing technology of kaolin varies with the nature of the raw ore, the use of the product and the quality requirements of the product. Generally speaking, the processing technology of kaolin includes: beneficiation and purification, ultra-fine processing, modification, etc. We is a professional manufacturer of kaolin clay processing equipment. Kaolin clay processing equipment such as kaolin clay Raymond mill, kaolin clay vertical mill and kaolin clay ultrafine mill have been widely used in the field of kaolin clay processing and have a good reputation. Today, I will introduce the ultra-fine processing technology and process flow of kaolin.
The main methods of kaolin ultrafine processing are: mechanical crushing method, classification method, intercalation-peeling method and chemical synthesis method.
(1) The mechanical pulverization method mainly uses the characteristics of the layered structure of minerals. Under the action of external force, the force between the layers is destroyed, so as to achieve the purpose of ultra-fineness, but the energy consumption is relatively large.
(2) The grading method mainly settles kaolin in liquid to obtain ultra-fine kaolin according to Stokes' rule, but the cost is high and the output rate is low.
(3) The intercalation-exfoliation method mainly uses intercalation to expand the interlayers of minerals in kaolin, and the bonding force is greatly weakened. Kaolinite, to achieve the purpose of natural peeling.
(4) The chemical synthesis method generally uses rock minerals or alumino-silica gel as raw materials to obtain ultra-fine synthetic kaolinite by hydrothermal method. It has high purity, good suspension stability, good light scattering and other properties.
Particle size is one of the important indicators to measure the quality of kaolin products, and the particle size and distribution of kaolin are also important factors affecting its viscosity. At present, the research on ultrafine kaolin mainly focuses on the intercalation-exfoliation method. Using high-purity soft kaolin as raw material, the intercalation-exfoliation method is used to prepare the nanoscale kaolinite wafers with an average diameter of 300~ 500nm, the average thickness reaches 20～50nm, suitable for strengthening agent of various rubber products.
At present, there are two common processing techniques of kaolin in industry: dry method and wet method.
(1) The dry process generally includes several processes such as crushing, drying (usually carried out in a rotary dryer), fine grinding and air flotation. This process can remove most of the sand and gravel, and is suitable for processing those ores with high whiteness, low sand and gravel content and suitable particle size distribution. Dry processing has low production cost and is generally suitable for dry areas. The products are usually used as low-cost fillers in industries such as rubber, plastics and papermaking.
(2) The wet process includes several stages such as slurry dispersion, classification, impurity sorting and product processing. The general process is: raw ore - crushing - mashing - sand removal - cyclone classification - peeling - centrifuge classification - magnetic separation (or bleaching) - concentration - filter press - drying - packaging.
(3) Coal-measure (hard) kaolin is a unique kaolin resource in my country. At present, the production process basically adopts the first ultra-fine and then calcined or the first calcined and then ultra-fine processing technology. The first ultra-fine and then calcined process is generally: raw ore - crushing - pulverization - mashing - wet ultra-fine grinding or peeling - drying - calcining - depolymerization - grading - packaging. The process flow of superfine after calcination is generally: raw ore - crushing - pulverization - calcination - wet superfine - drying - packaging.
Taking China Kaolin Company as an example, the kaolin production process is divided into two parts: mining and beneficiation. Mining process: mining face rock drilling - blasting - loading and unloading transportation - lifting - ground transportation - hand selection - kaolinite ore. Process flow of beneficiation: raw kaolin ore - crushing - pulping - cyclone classification - concentration - filter press - natural drying - bulk kaolin. To produce powdered kaolin with low water content and high grade, grinding and drying processes are required.