Kaolinite is a mineral from the group of aluminosilicates. It is not only beautiful, but also very useful. Today, this miracle mineral is widely used in the construction, pulp and paper, food industries, as well as in pharmaceuticals, cosmetology and dentistry. You will find detailed information about the application, varieties and properties of the kaolinite mineral in our article.
Stone from "High Hill"
This soft, earthy mineral is ubiquitous on our planet. But for the first time it was discovered by the Chinese near the village, located on a high gentle hill. The village was called Kao-Ling, which means "High Hill" in Chinese. By the way, this is where the term "clay" comes from. When exactly the mineral kaolinite was discovered by the Chinese is unknown. However, Europeans learned about its existence only in the century before last.
The mineral kaolinite belongs to the class of hydrous aluminum silicates. Its formula is as follows: Al4[Si4O10](OH) 8. AtThe chemical composition of kaolinite is:
- Silicon dioxide - 47%.
- Alumina - 39%.
- Water - 14%.
It is necessary to distinguish between the concepts of "kaolinite" and "kaolin". The first is a mineral, and the second is a rock. Kaolinite is the main component of most clays.
Physical and chemical properties of the mineral
Kaolinite, as we have already found out, is a clay mineral, which in nature forms dense, finely dispersed geological masses. We list its main mechanical, physical and chemical properties and features:
- Hardness: 1.5-2 points (Mohs scale).
- Density: 2.6-2.7g/cm3.
- Refractive index: 1.56.
- Shine: dull, earthy.
- Kink: conchoidal.
- Mineral color: grayish, greenish, white, brown, pale yellow (thin flakes may have a pearly sheen).
- Line color: white.
- The mineral kaolinite crystallizes in a triclinic syngony.
- It is opaque in a piece, but individual plates are translucent.
- Gold to the touch.
- Absorbs moisture well.
- When heated to 500 degrees, it loses water, and at 1000-1200 degrees it decomposes with the release of heat.
- Dissolves in sulfuric acid.
Fields and production
Kaolinites occur both within the continental crust and in the zone of the ocean floor. The mineral is formed in the process of so-called kaolinization, which is accompanied by chemical weathering andhydrothermal alteration of feldspars and other silicates.
The mineral kaolinite is a constituent of various clays, marls and shale. Its largest deposits are located in the southeastern part of China. Quality kaolins are also mined in Russia (Urals), Ukraine (Zhytomyr, Kyiv and Ternopil regions), Great Britain (Cornwall), Germany (Meissen, Halle), Czech Republic (Sedlec), Uzbekistan, Kazakhstan and Bulgaria.
It is worth noting that the process of extracting kaolins from the earth's crust is not particularly costly. They are mined mainly by an open (quarry) method. So, for example, a clay quarry looks like in Ukraine (Terebovlya city, Ternopil region):
But this view (photo below) has already been mined and crushed kaolinite in Spain.
History of the use of the mineral
As mentioned above, there is no information about how long ago the Chinese discovered kaolinite. But they did it first. At least, this is evidenced by the highest quality of ancient Chinese porcelain. Back in the third century BC, Chinese craftsmen created their own unique "Terracotta Army", consisting of eight thousand clay statues of warriors and horses.
The technology of processing kaolinite into "white gold" has long been classified by the masters of the Celestial Empire. In Western Europe and Russia, porcelain was made only in the 18th century. The first factories grew in German Meissen and French Sevres. In 1744 in St. Petersburg was foundedThe Imperial Porcelain Factory, still in operation today.
The mineral kaolinite: applications today
It is easy to guess that the main consumer of this mineral is the porcelain and ceramic industry. It is worth noting that the manufacture of high-quality porcelain is a rather complicated and troublesome process. Fortunately, the stone itself is not uncommon and easy to mine. Porcelain is made from refined kaolinite. Previously, it is removed from various impurities in centrifuges and hydrocyclones. After that, the raw materials are dehydrated in order to reduce weight and increase the strength of the final product.
Besides this, the mineral kaolinite is also used in the production of coated paper, art glaze, toothpaste. Based on kaolin wool, industrial filters, electrical insulating gaskets, and heat-insulating materials are made. Plus, kaolins (white clay) are widely used in cosmetology and traditional medicine. Thus, the consumption of kaolinite in the modern world is quite solid.
Main varieties of the mineral
In fact, under kaolinites, geologists mean a fairly large group of different minerals. The most common among them are:
- Rhodalite.
- Terratolite.
- Keffekelit.
Rhodalite is a mineral with a pink tint due to iron impurities. Produced in Northern Ireland. Terratolite is a mixture of quartz, mica, limonite and, in fact, kaolinite. The color of the mineral is blue-violet. Keffekelite contains impurities of halloysite and some other clay minerals and is distinguished by greenish-yellow hues. In China, there are also deposits where a mixture of kaolinite with dickite, quartz and cinnabar is mined. This mineral has a specific name - "chicken blood".
It would be useful to note that some varieties of kaolinite are quite beautiful. Therefore, they are actively used in decorating furniture and inlaid jewelry.
Healing properties of kaolins
Clay is often called a "natural healer", as well as a "remedy for a hundred diseases." After all, it contains a large number of trace elements useful for the human body. These are magnesium, calcium, potassium, iron, nitrogen, etc. But the most important thing is that all these trace elements and substances in kaolins are present in combinations and ratios that are optimal for humans.
Some clays contain radioactive elements such as radium. But as a rule, their percentage in the breed does not exceed the permissible norms. A high degree of radioactivity is typical only for those clays that occur in contaminated industrial areas.
Clay in cosmetology and folk medicine
All cosmetologists know about the healing properties of the so-called white clay. The latter acts as an absorbent: cleanses the skin, removing toxins and toxins from it. After clay masks, the skin looks fresher and he althier, small wounds heal and scars heal. Kaolin has a beneficial effect on the hair, preventing themfragility.
In folk medicine, clay helps with sore throats and headaches. To do this, it is applied in a thin layer to sore spots. Some healers are convinced that kaolin is able to cure a person from such serious ailments as arthritis and pneumonia. Tooth powder is also made from white clay. With gastrointestinal disorders, flatulence, alcohol poisoning, clay is taken orally (of course, in small quantities).
In conclusion…
Kaolinite is a cheap, but at the same time incredibly useful mineral. After all, it is used in a wide variety of fields and industries. So, it is used in the production of porcelain and ceramics, paper and filters, medicines and food additives. The healing properties of this mineral are widely used in cosmetic and medical purposes.
