Kaolin mainly composed of kaolinite, halloysite composition 90 containing the most up to the above, then there hydromica, often mixed with pyrite, exposing iron, anatase, quartz, chalcedony, alum stone, Sometimes there is a small dish of organic matter. The processing technology of kaolin ore depends on the quality of the ore and the end use of the product. There are two processes applied in industrial production: dry process and wet process. The dry process is a simple and economical process. The produced ore is crushed to about 25mm by the crusher and then given to the cage crusher to reduce the calibration to about 6 mm and blown into the cage crusher. The hot air inside will reduce the moisture of the ridge from 20% at the time of production to about 10%. 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. The nature of the dry processed kaolin product often reflects the original nature of the natural kaolin, so the dry process is suitable for ore with high whiteness, low sand content and suitable particle size distribution. Low cost, the product is usually used in low-cost fillers in the rubber, plastics and paper industries. The wet process includes three stages: ore preparation, beneficiation processing and product processing. The principle flow is shown in Figure 7-1. The preparation stage includes the operations of batching, crushing and sizing. The mash is to mix the kaolin with water and dispersant in the pulverizer. The purpose of the mash is to break up the kaolin ore and prepare the appropriate fineness for the beneficiation operation. Gao Ling soil slurry, and at the same time Remove the large grain of sand. The beneficiation stage may include hydraulic grading, flotation, selective flocculation, magnetic separation, chemical treatment (bleaching), etc. to remove different impurities. The prepared slurry can be de-sanded by a rake classifier, a floating classifier or a hydrocyclone, and then continuously separated, a machine, a hydrocyclone, a hydraulic separator or a vibrating fine screen (325 mesh). Divided into two grades of coarse and fine. If the product can meet the requirements of certain industries, it can also be added with a flocculant (such as alum) to coagulate the kaolin and facilitate dehydration. If high quality kaolin is needed (such as For example, kaolin with a whiteness of more than 85) requires magnetic separation, bleaching, flotation or selective flocculation in most cases. However, these separate operations have their own advantages and disadvantages, so two types are commonly used in industry. And even the joint process of 3 kinds of operations. Impurities such as kaolin stained anatase, rutile, hematite, mica and weakly magnetic pyrite etc., using a high gradient magnetic separator may thus be removed, for example, PEM-84 type high gradient wet use abroad The magnetic separator can reduce Fe2O3 in kaolin ore from 0.9% to 0.6%, and TiO2 from 1.8-2.0% to 0.8%. In recent years, superconducting magnetic separator has been reported to be used for sorting kaolin, not only energy consumption. Reduced, and the field strength can be greatly improved, resulting in a higher quality kaolin concentrate. The chemical bleaching process of kaolin is to transfer the kaolin slurry into the washing tank, adjust the pH value to 4.5-5 with sulfuric acid, and then inject into the bleaching reaction tank, adding a reducing agent (Na2S2O4 or ZnS2O4) to make the trivalent in the mineral. The iron is reduced to ferrous iron and dissolved in the slurry. It can be washed with water to separate it from the kaolin. In order to remove the dark organic matter, it can be bleached with a strong oxidizing agent (hydrogen peroxide, sodium hypoxoxide, etc.). To improve the whiteness of kaolin, but the cost of this process is high, and strict environmental protection measures are required. Object of flotation is selected from kaolin anatase floating. Since the pull fine particles of anatase, a carrier can be used flotation process. The carrier mineral may be calcite , silica sand, etc. (less than 325 mesh), the carrier mineral is generally used in an amount of 10-20% by weight of the kaolin, and a part of the carrier may be recycled for reuse. The agents used in the flotation process include the following: dispersant sodium silicate, pH adjuster ammonium hydroxide and caustic soda, collector Tal oil, fatty acid and petroleum sodium sulfonate. The coating grade kaolin for papermaking with a whiteness of more than 90% has been produced by carrier flotation process since 1961. The disadvantage of this process is that the consumption of the agent is large, and the agent and carrier mineral remaining in the kaolin concentrate have harmful effects. . Recently, a process for directly floating out of the kaolinite from kaolin has been studied, which is characterized by high pulp concentration in the presence of a dispersant (such as sodium silicate) and a pH adjuster (usually used as a hydroxide). -60% solids) scrubbing to remove contaminated minerals from the surface, while scrubbing also dissociates the sharp-min and hematite from the minerals on the kaolin. A small amount of activator and fatty acid collector are added to the slurry. The captured anatase forms selective agglomeration under high shear agitation conditions, so that the particle size is significantly increased. The slurry after high shear stirring and slurry is diluted to 15-20% solids for flotation. Kaolin The alum in the middle can also be removed by flotation. Selective flocculation is carried out by adding Ca2+, Mg2+ ions to the kaolin slurry and then using a weak anionic polyelectrolyte as a flocculant at a pH of 8-11. The selective flocculation of titanium and iron impurities can be observed. The removal of impurities containing very fine impurities, kaolin, is an efficient method, but the process requires a slurry concentration of less than 20%, so there must be a large amount of water to be removed in the subsequent operations, while the residual flocculant has a quality for the final product. influences. Kaolin products can be dehydrated by high-speed centrifuge, vacuum filter or filter press, and then can be dried into powder or block products, or can be sold in a slurry content of about 70% solids. Sintering Furnace,Vacuum Sintering Furnace,Continuous Sintering Furnace,High Temperature Sintering Furnace Zhejiang Shangding Industrial Furnace Co., Ltd , https://www.sdindustrialfurnace.com