Subdivision of carbonate mineral composition

Dolomite is also known as the carbonate mineral of snowflake white triangle system. The chemical composition is CaMg (CO3) 2. Iron and manganese (not magnesium) are usually similar. When the number of iron or manganese atoms exceeds the number of magnesium, it is called the manufacturer of iron dolomite or manganese dolomite. In triangular crystal system, the crystal is rhombohedron, and the crystal surface is often bent into saddle shape. Aggregates are usually granular. Pure is white. It is gray when it contains iron; It is brown after weathering. Glass luster. It is the main mineral of dolomite. Marine sedimentary dolomite usually occurs in the interlayer with siderite and limestone. In the lake sediments, dolomite coexists with gypsum, anhydrite, halite and potash.

It is found that when dolomite is heated to 700-900 ℃, it will decompose into a mixture of carbon dioxide, calcium oxide and magnesium oxide, which is called caustic magnesite. This kind of stone reacts easily with water. When dolomite is 1500 ° When calcined at C, MgO turns into brucite, while Cao turns into crystalline a-cao. This material has dense structure, strong water resistance and up to 2300 ° C.

The data show that dolomite deposits in China are distributed in carbonate series. The older the strata are, the more the sediments are, and most of them are deposited at the bottom of Sinian. For example, there are dolomite deposits in Xiuyan area of Dong'an mountain, Inner Mongolia Sangzi group and Fujian Jianou group.