How is kaolin formed?

How is kaolin formed?

After several million years of long-term weathering, feldspar rocks form kaolin: K20 and Na20 are water-soluble components, most of which are taken away by water. If the weathering is not complete, part of the feldspar will form muscovite, and some of the parent rock will still exist in the form of feldspar because it is buried deep underground and cannot be weathered. Some sedimentary kaolin are deposited at the same time as certain impurities during the formation process.

According to geological origin, kaolin is divided into two types, namely primary kaolin and sedimentary kaolin. Primary kaolin refers to the kaolin remaining with the parent rock after the rock is weathered without being transported by natural forces. Kaolin produced in southern China is mainly of this type. Sedimentary kaolin refers to kaolin that has been transported and deposited by natural forces and mixed with various impurities during the transport and deposition process. Kaolin in northern my country mostly belongs to this type.

  1. Kaolin is a kind of clay mainly composed of kaolinite. After the feldspar is completely weathered, kaolin, quartz and soluble salts are formed; then it is transferred to another place with rain and river drifting and deposited again. At this time, the quartz and soluble salts have been separated, and kaolin can be obtained. Kaolin occupies the largest amount of porcelain and is a good raw material for porcelain production. Minerals on the earth are mainly divided into three types: energy minerals, metallic minerals and non-metallic minerals. Kaolin is an important non-metallic mineral, and it is called the four major non-metallic minerals together with mica, quartz and calcium carbonate.
  2. Kaolin is mainly composed of kaolinite cluster minerals (kaolinite, dickite, perlite, halloysite, etc.) smaller than 2 microns, such as tiny flakes, tubes, and laminates. The ideal chemical formula is AL203-2SIO2- 2H20, its main mineral components are kaolinite and halloysite. In addition to kaolinite cluster minerals, there are also other minerals such as montmorillonite, illite, pyrophyllite, quartz and feldspar. The chemical composition of kaolin contains a large amount of AL2O3, SIO2, a small amount of Fe203, TIO2, and a small amount of K20, Na2O, CaO and MgO.
  3. Kaolin is a kind of sedimentary rock on the earth, not volcanic rock. Sedimentary rocks are formed during the movement and development of the earth. These ancient sedimentary rocks are rock salt after weathering. After being deposited for tens of thousands of years or more, they are exposed to the ground through orogeny during the formation of the earth, forming mountains and hills. Kaolin mountain. To be precise: it is a kind of sedimentary rock formed by loose mineral particles or organic matter, such as sandstone, gravel, clay, mortar, biological debris, etc., on land or in rivers, rivers, lakes, and sea basins. Followed by volcanic eruptions, organic matter and cosmic matter, and kaolin is the formation of some of these substances, and it is also formed by mudstone or shale. The formation of kaolin minerals. The formation of kaolin is the sedimentary rocks of rivers and lakes on the ancient earth billions of years ago. After being exposed to the ground through orogeny, it went through primitive earth movement. Many volcanic plates made gravel, clay, mortar, biological debris, mudstone, and shale Rocks and granites are formed with multiple components. In terms of the composition of kaolin, there are quartz, feldspar, halloysite and a small amount of montmorillonite. It also contains mica detrital minerals, as well as aluminum, iron, carbon, acid, salt, and silicate minerals. Kaolin has many rock components, such as quartz, feldspar, montmorillonite, mica fragments, halloysite, aluminum, iron, carbon, acid, salt, etc.

China is the first country in the world to discover and use kaolin. The carved white pottery that appeared in the Shang Dynasty 3000 years ago was made of kaolin. The porcelain produced in Jingdezhen, Jiangxi Province is well-known both at home and abroad. It has always been known as “white as jade, bright as a mirror, thin as paper, and sound as exhausted”. Kaolin, the scientific name of kaolin that is now commonly used internationally, is derived from the Kaolin Mountain near Gaoling Village in the eastern suburbs of Jingdezhen.

Chinese kaolin mineral resources rank among the top in the world, with 267 proven mineral deposits and a proven reserve of 2.91 billion tons. Among them, China’s non-coal-built kaolin has the fifth largest resource reserves in the world. The proven reserves of 1.468 billion tons are mainly concentrated. The six provinces of Guangdong, Shannxi, Fujian, Jiangxi, Hunan and Jiangsu account for 84.55% of the country’s total reserves; coal-bearing construction kaolin (kaolin) reserves ranks first in the world, with a proven reserve of 1.442 billion tons, mainly located in Datong, Shanxi. Huairen, Shuozhou, Inner Mongolia Zhungeer, Wuda, Anhui Huaibei, Shaanxi Hancheng, etc. Among them, Inner Mongolia Zhungeer coalfield has the most resources.

There are five major kaolin deposits in China:

  1. Jiepai Town, Hengyang County, Hunan Province is rich in mineral resources. The reserves of kaolin, feldspar, potash feldspar and quartz reach 200 million tons, and there are nearly 40 mining and mineral processing enterprises. The Dapailing mining area (mainly kaolin mine) reserves the largest single mine in Asia, reaching 80 million tons. The town’s annual mining volume is over 500,000 tons, which supplies hundreds of ceramic factories across the country.
  2. Kaolin in Maoming area. Kaolin deposits in Maoming Basin belong to sedimentary rock weathered residual subtype deposits, and their sand content such as quartz is greater than 50%, so they are called sandy kaolin deposits. From the origin of Maoming kaolin, it has undergone weathering residue-transportation and self-grinding;-three stages of re-weathering. The kaolin is completely weathered, and the wafers are mainly monolithic with fine grain size. Mainly as raw materials for papermaking coatings.
  3. Longyan kaolin is a weathered residual kaolin deposit. Since the iron content is less than 0.3%, titanium is less than 0.02%, and contains a certain amount of low-temperature solvent element (Li2O), it is an ideal raw material for electric porcelain, high-end daily-use and fine art porcelain.
  4. Suzhou Yangshan kaolin, the deposit is hydrothermal altered kaolin. The pure texture of Suzhou Yangshan mud has a chemical composition that is very close to the theoretical composition of kaolinite. The content of Al2O3 can be as high as 39.0%, the color is white and the particles are fine. Mainly used for catalyst carrier and chemical raw materials.
  5. Hepu Kaolin: It belongs to the kaolin deposit of weathered residual type. Mainly used as raw materials for building ceramics.
  6. Northern coal-measure kaolin: it is sedimentary kaolin, mainly distributed in my country’s domestic coal areas, and can be used for construction, paint, paint and paper coatings-coal-measure soil.

The above-mentioned six major producing areas account for more than 80% of China’s output, and they are also representative in terms of resource types.


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