Diatomite is a kind of siliceous rock, which is mainly distributed in China, the United States, Denmark, France, Romania and other countries. It is a biogenic siliceous sedimentary rock, which is mainly composed of the remains of ancient diatoms. Its chemical composition is mainly SiO2, which can be expressed by SiO2 · nH2O, and its mineral composition is Opal and its variants. China's Diatomite reserves are 320 million tons and the prospective reserves are more than 2 billion tons. It is mainly concentrated in East China and Northeast China, of which Jilin (54.8%), Zhejiang, Yunnan, Shandong, Sichuan and other provinces have large-scale reserves. Although it is widely distributed, the high-quality soil is only concentrated in Changbai Mountain, Jilin. Most of other deposits are grade 3 ~ 4 soil. Due to the high content of impurities, It cannot be directly processed and utilized.

The chemical composition of diatomite is mainly SiO2, containing a small amount of Al2O3, Fe2O3, Cao, MgO and organic matter.

The density of diatomite is 1.9-2.3g/cm3, the bulk density is 0.34-0.65g/cm3, the specific surface area is 40-65m / g, the pore volume is 0.45-0.98m, the water absorption is 2-4 times its own volume, and the melting point is 1650c-1750 ℃. The special porous structure can be observed under the electron microscope.

It contains a small amount of Al2O3, Fe2O3, Cao, MgO, K2O, Na2O, P2O5 and organic matter. SiO2 usually accounts for more than 80%, up to 94%. The iron oxide content of high-quality diatomite is generally 1 ~ 1.5%, and the alumina content is 3 ~ 6%. The mineral composition of diatomite is mainly Opal and its variants, followed by clay minerals - hydromica, kaolinite and mineral debris. Mineral fragments include quartz, feldspar, biotite and organic matter. The content of organic matter ranges from trace to more than 30%. The color of diatomite is white, grayish white, gray and light grayish brown. It has the properties of fine, loose, light, porous, strong water absorption and permeability. Most of the silica in diatomite is amorphous, and the content of soluble silicic acid in alkali is 50 ~ 80%. Amorphous SiO2 becomes crystalline when heated to 800 ~ 1000 ° C, and the soluble silicic acid in alkali can be reduced to 20 ~ 30%.

Diatomite is a kind of siliceous rock, which is mainly distributed in China, the United States, Denmark, France, Romania and other countries. China's Diatomite reserves are 320 million tons, and the prospective reserves are more than 2 billion tons. It is mainly concentrated in East China and Northeast China, of which Jilin, Zhejiang, Yunnan, Shandong, Sichuan and other provinces have done more work. Although it is widely distributed, the high-quality soil is only concentrated in Jilin Changbai and Yunnan diatomite mining areas, which is particularly rich in resources. Most of other deposits are grade 3 ~ 4 soil, Due to the high content of impurities, it can not be directly processed and utilized.

Diatomite is composed of amorphous SiO2 and contains a small amount of Fe2O3, Cao, MgO, Al2O3 and organic impurities. Diatomite is usually light yellow or light gray, soft, porous and light. In industry, it is often used as thermal insulation material, filter material, filler, grinding material, water glass raw material, decolorizing agent, diatomite filter aid, catalyst carrier, etc.

The special porous structure of natural diatomite can be observed under the microscope. This microporous structure is the reason why diatomite has characteristic physical and chemical properties.

The main component of diatomite as carrier is SiO2. For example, the active component of industrial vanadium catalyst is V2O5, the cocatalyst is alkali metal sulfate, and the carrier is refined diatomite. Experiments show that SiO2 stabilizes the active components and strengthens with the increase of K2O or Na2O content. The activity of the catalyst is also related to the dispersion and pore structure of the support. After diatomite is treated with acid, the content of oxide impurities decreases, the content of SiO2 increases, and the specific surface area and pore volume also increase. Therefore, the carrier effect of refined diatomite is better than that of natural diatomite.

Diatomite is generally formed from silicate remains after the death of unicellular algae collectively known as diatoms. Its essence is aqueous amorphous SiO2. Diatoms can exist in both fresh and salt water. There are many kinds of diatoms, which can be generally divided into "central order" diatoms and "plume order" diatoms. In each order, there are many "genera", which are quite complex.

The main component of natural diatomite is SiO2. The color of high-quality diatomite is white, and the content of SiO2 often exceeds 70%. The monomer diatom is colorless and transparent. The color of diatomite depends on clay minerals and organic matter. The composition of diatomite from different mineral sources is different.

Diatomite is a fossil diatomite deposit formed after the death of a single celled plant called diatom and a accumulation period of about 10000 to 20000 years. Diatom is one of the earliest protozoa on earth, living in seawater or lake water.

This diatomite is formed by the deposition of the remains of unicellular aquatic plant diatom. The unique property of this diatom is that it can absorb free silicon in water to form its bones. When its life is over, it will deposit and form diatomite deposit under certain geological conditions. It has some unique properties, such as porosity, low concentration, large specific surface area, relative incompressibility and chemical stability. After changing its particle size distribution and surface properties through processing processes such as crushing, sorting, calcination, air flow classification and impurity removal, it can be applied to a variety of industrial requirements such as coatings and paint additives.