Diatomite is a kind of light porous siliceous biosedimentary rock formed by diatom silicate remains.

chemical composition

The chemical composition of diatomite is mainly amorphous SiO2, which exists in the form of SiO2 · nH2O. SiO2 usually accounts for more than 80%, up to 94%. It contains a small amount of Al2O3, Fe2O3, Cao, MgO, K2O, Na2O, P2O5 and organic matter, and some metal impurities such as Cr and ba. The composition and content of diatomite ore in different places are different.

physical property

The color of diatomite is white, grayish white, gray, light gray, light grayish brown, light yellow, etc; Density: 1.9 ~ 2.3g/cm3; Bulk density: 0.34 ~ 0.65g/cm3; Melting point 1650 ℃ ~ 1750 ℃; Specific surface area 19 ~ 65cm2 / g; Pore volume: 0.45 ~ 0.98cm3/g; The water absorption is 2 ~ 4 times of its own volume. High chemical stability, insoluble in hydrochloric acid and easily soluble in alkali. It has many excellent properties such as relative incompressibility, soft, sound insulation, wear resistance, heat resistance and so on.

Development and Application

Because of its unique physical and chemical properties, diatomite has been widely used as filter aid, functional filler, catalyst carrier, pesticide and fertilizer carrier, thermal insulation material, adsorbent and bleaching material.

Food and pharmaceutical industry

Diatomite is used as filter aid in food industry

Because of its strong adsorption capacity, diatomite is used as filter aid in food industry to remove bacteria, impurities and peculiar smell. If diatomite filtration is used in the brewing process, the filter bed can be continuously updated, with fast filtration speed and large output; With large surface area and strong adsorption capacity, it can filter out 0.1 ~ 1.0um particles, reduce wine loss by about 1.4%, and improve production and operation conditions.

Diatomite filter can better improve the effluent quality of circulating water treatment in swimming pool, and can save water and electricity in the operation and management of swimming pool. Secondly, diatomite is also widely used in edible oil, pharmaceutical oral liquid and so on.

Environmental protection industry

Diatomite for sewage treatment

Diatomite is widely used in wastewater treatment because of its stable chemical properties, strong adsorption capacity, good filtration performance and insoluble in any strong acid. The pretreatment of landfill leachate by diatomite flocculation sedimentation method can preliminarily reduce CODcr and BOD5 in the leachate and remove SS and other pollutants, so as to improve its biochemistry, reduce the load and create good conditions for the normal operation of subsequent biochemical treatment.

Construction industry

Application of diatomite in road asphalt

Diatomite has the characteristics of light weight, soft, porous, acid resistance and stable chemical properties, which can greatly improve the performance of asphalt mixture. Diatomite modified asphalt used in asphalt concrete pavement not only has the advantages of low cost, simple construction and guaranteed raw material supply, but also can improve the durability, wear resistance, thermal stability, compressive strength and skid resistance of the pavement, reduce the diseases such as oil flashing, slurry squeezing and rutting of the pavement, improve the service life of the pavement and save the cost of highway maintenance and maintenance.

construction industry

Diatomite is used to make insulating bricks

In recent years, with the increasing shortage of land resources in China and the increasing number of high-rise buildings, a large number of lightweight wall materials came into being in order to reduce the weight of buildings. The sintered brick with diatomite as raw material is favored because of its low density, high strength, thermal insulation, sound insulation and heat insulation. Diatomite is not only an excellent raw material for preparing light insulation board, calcium silicate insulation material, diatomite insulation brick, diatomite amorphous insulation material and insulation pipe, but also one of the raw materials for waterproof and seepage prevention. In addition, diatomite not only has the characteristics of non combustion, sound insulation, waterproof, light weight and heat insulation, but also has environmental protection functions such as dehumidification, deodorization and indoor air purification.

Agriculture

Diatomite soil conditioner

Diatomite as an insecticide has many advantages, such as non-toxic, tasteless, good insecticidal effect, no environmental pollution, ensuring grain storage quality and so on. As a soil conditioner, amorphous active diatomite particles are a good carrier of fertilizer and water required by plants. They can effectively adjust the absorption and release of water according to soil humidity. They can also have the functions of moisture retention, air permeability and drying. They play a great role in plant root growth and water and soil conservation.

Coating industry

Diatomite for interior wall coating

Diatomite can be made into interior wall coating, which is characterized by non reflective walls and soft indoor light. The Japanese call the wallpaper coated with diatomite "breathable wall". The application of diatomite in exterior wall coating is also developing, and its prospect is broad. In addition, diatomite is also widely used in the fields of resin, rubber, papermaking, concrete, cement filler and various decorative thermal insulation coatings.

Reserves and distribution

Diatomite is an important non-metallic mineral resource with considerable reserves in China. More than 70 diatomite deposits have been found in more than 10 provinces (autonomous regions) such as Jilin, Yunnan, Zhejiang, Sichuan, Inner Mongolia, Shandong, Guangdong, Hebei, Hainan and Heilongjiang. The total proved reserves are more than 400 million tons and the prospective reserves are more than 2 billion tons. High quality diatomite was found in Changbai Mountain Area of Jilin Province (Linjiang city and Changbai County), Inner Mongolia, Xuwen of Guangdong Province and Tengchong of Yunnan Province. Among them, Jilin Province has the largest proved reserves, about 210 million tons, accounting for about half of the country, and the prospective reserves exceed 1 billion tons. The proven reserves in Changbai Mountain Area of Jilin are more than 60 million tons and the prospective reserves are more than 600 million tons. It is the largest high-quality diatomite resource reserve in China and one of the high-quality diatomite producing areas with reserves of tens of millions of tons in the world. The proved reserves of Yunnan Province are 82 million tons, accounting for about 20% of the national proved reserves, and the prospective reserves exceed 600 million tons. The proved reserves of Zhejiang Province are 43 million tons, accounting for about 10% of the national proved reserves, and the prospective reserves are more than 200 million tons. The proved reserves of Jilin, Yunnan and Zhejiang provinces account for about 80% of China's proved reserves; The remaining provinces and autonomous regions account for about 20%.