Magnesite - Chemical Part
Crystal chemistry
Theoretical composition (wB%): 47.81, CO2 52.19. The complete isomorphism can be formed between MgCO3-FeCO3, and the content of FeO in natural magnesite is generally<8%. About 9% of FeO is called iron magnesite; the more abundant is called Lingmei magnesium. Sometimes, it contains a mixture of Mn, Ca, Ni, Si, and the like. Dense block often contains impurities such as opal and serpentine.
Structure and morphology
Trigonal system, rhombohedral unit cell: arh = 0.566 nm, α = 48. 10'; Z = 2; hexagonal unit cell: ah = 0.462 nm, ch = 1.499 nm; Z = 6. Calcite structure.
Complex three-sided triangular facet crystal, D3d-3m (L33L23PC). Crystals are rare. Main simplex: rhombohedron r, f, hexagonal column m, a, parallel double-sided c, complex three-sided triangular facet v. Often a grainy or cryptocrystalline dense block. In the weathering zone, it is often cryptocrystalline.
Physical and chemical properties
White or light yellow white, grayish white, sometimes with a reddish hue, iron-bearing yellow to brown, brown; ceramics are mostly snow white. Glass luster. With complete cleavage. The porcelain is a shell-like fracture. Hardness 4~4.5. Crisp. The relative density is 2.9~3.1. Both the iron-bearing density and the refractive index increase. The cryptocrystalline magnesite is densely packed and looks like unglazed porcelain, so it is also called porcelain magnesite.
Under the polarizer: the one-axis crystal (-), the refractive index and the birefringence ratio become larger as the iron content increases. Has a high rate of redeem. Birth and combination
Industrial deposits are usually formed by metathesis of dolomite, magnesite dolomitic limestone or ultrabasic rock with a hot aqueous solution containing magnesium. Often associated with calcite, dolomite, chlorite, talc. The magnesite is formed at 250~350 °C under normal pressure; below this temperature, a stable trihydrate magnesite is formed; above this temperature, brucite is formed.
North Korea is the country with the most abundant magnesite resources in the world. It has a total reserve of 6 billion tons of ore, ranking first in the world. The important characteristics of magnesite in China are that the area is not widely distributed, the reserves are relatively concentrated, and there are many large deposits. There are 27 mines with proven reserves. The type of deposit is characterized by sedimentary metamorphism-hydrothermal metasomatism, such as magnesite production in Haicheng, Yingkou, Liaoning, and magnesite production in Jixian, Shandong; sedimentary, hydrothermal vein and basic-ultrabasic rocks Type is not important. Chinese magnesite is mainly formed in the Pre-Sinian and Sinian, and a few deposits were formed in the Paleozoic and Mesozoic.
Identification characteristics: similar to calcite, but the cold hydrochloric acid does not blister or the effect is very slow, and the heated hydrochloric acid violently foams.
Industrial applications: mainly used as refractory materials, building materials, chemical raw materials and refined magnesium and magnesium compounds.
FENGCHENG CITY HEQI BRUCITE MINING CO., LTD is registered in Dandong city, Liaoning province. Sufficient talent reserves, proper environmental governance, convenient transportation and communication.We are mainly engaged in the purchase, processing and sales of mineral products.
Main products: magnesium hydroxide flame retardant and brucite powder. Complete specifications of products, welcome to visit our factory guidance.
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