Dolomite is a kind of carbonate mineral, whose chemical formula is CaCO3.MgC03 or CaMg(C03) theoretical composition is w(CaO)= 30.4%, w(MgO)= 21.7%, w(CO2)= 47.9%, often containing Fe, Si and Mn impurities. The density of dolomite is 2.8 ~ 2.9g/cm3, the hardness is 3.5 ~ 4, the decomposition temperature is 730 ~ 900℃, the decomposition temperature is 730 ~ 790℃, the decomposition of free MgO and CaCO3 around 900℃. Dolomite belongs to the tripartite system, the crystal is curved saddle-shaped rhombohedron, the aggregate is crystalline granular and dense massive, often associated with calcite, clay, chert and magnesite. Dolomite is widely distributed in nature and can be found in any region. It is mainly distributed in northeast China, Hubei Province and Southwest China. Dolomite has the characteristics of surface adsorption, can provide magnesium calcium source, high refractories, large specific surface area, good heat insulation and heat preservation effect, and is widely used in metallurgy, building materials, agriculture, forestry, glass, ceramics, chemical industry and environmental protection and other fields.

property

Dolomite is a kind of mineral, its chemical composition is calcium, magnesium carbonate (chemical formula CaMg(CO3)2), crystal belongs to the tripartite system of carbonate minerals. The crystal structure of dolomite is similar to that of calcite. The crystal shape is rhombohedral, and the crystal surface is often curved into saddle shape. Pure white marble is white, because of other elements and impurities sometimes gray green, gray yellow, pink and other colors, glass luster. Three groups of rhombohedral cleavage complete, brittle. Mohs hardness 3.5-4, specific gravity 2.8-2.9. Mineral powder reacts slowly in cold diluted hydrochloric acid.

use

One of the many uses of dolomite is preservative, especially in water systems. Dolomite is used in water filters, pipe linings and backfill.

1. Water filtration medium

After being treated to make it drinkable, the water is usually soft, low in minerals, and fairly acidic - typical of "corrosive" water. In addition to damage to pipes, corrosion can make the water smell bad, create stains and become toxic.

Small water distribution systems typically use alkaline medium filters or contactors, as well as filtration beds containing dolomite through which the water is adjusted to pH levels of 7 to 8. High pH levels are also a problem, as highly alkaline water can also be corrosive.

Water with the right amount of calcium or magnesium salts (to avoid hard water scaling) is also less corrosive because the minerals coat and protect the lining of the pipe while improving the taste of the water. Dolomite in a filter or contactor is a good source of these minerals because dolomite dissolves in slightly acidic water when filtered.

2. Pipe lining material

It has been shown that the corrosion rate of pipe walls with dolomite coating is lower than other materials.

3. Bedding and backfill materials

Bedding and backfill materials including dolomite protect underground pipes from corrosion.

Water from desalination or reverse osmosis treatment is usually passed through an alkaline medium filter containing dolomite to avoid corrosion and improve taste.