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How to intensively process dolomite?

Source:Shanghai Clirik Machinery Posted:06-04-2021 17:52

How to intensively process dolomite? What are the application areas?

The chemical composition of dolomite is CaMg(CO3)2, and the crystal is a carbonate mineral of the trigonal crystal system. The crystal structure of dolomite is similar to that of calcite. The crystal form is rhombohedron, and the crystal face is often bent into a saddle shape. The double crystals are common, mostly in the block and granular aggregates. Pure dolomite is white because it contains other elements and impurities, sometimes it is gray-green, gray-yellow, pink, and other colors and the glass is shiny. The three groups of rhombohedrons are completely cleavage and brittle. Mohs hardness is 3.5-4, specific gravity is 2.8-2.9. Mineral powder reacts slowly in cold dilute hydrochloric acid.

 

Dolomite is sorted, crushed, and ground into dolomite powder from 325 to 2000 meshes. With the scale of the dolomite powder industry and the upgrading of application requirements, the traditional small-scale and multi-equipment extensive processing mode can no longer meet the market demand. Therefore, the use of new It is imperative to improve the processing scale and technical level of the company’s powder technology and equipment. The CLUM series of ultra-fine vertical mills are the crushing, drying, grading, transportation, secondary powder selection, and finished products developed by Kolyric for many years. A comprehensive mill with six major functions such as packaging can effectively increase the added value of dolomite products. The output of the same product CLUM series ultrafine vertical mills can be increased by 30%.
 

The dolomite powder processed by the ultrafine vertical mill can be added to natural rubber and synthetic rubber. Its rubber performance is the same as that of light calcium powder, but the cost is lower than that of light calcium powder. Dolomite is used to produce rubber general-purpose calcium-magnesium powder. As a new type of additive and coloring agent, it can partially or completely replace light calcium powder. The surface-modified dolomite powder can greatly increase the reinforcing performance of rubber products. Modified dolomite powder uses a surface modifier to coat the surface of dolomite powder, and then it is used as filler. Commonly used surface modifiers include stearic acid or stearate, titanate, zirconium aluminate, and mixed silane coupling agents. The purpose of the modification is to change the surface alkalinity of dolomite powder, overcome the bonding performance between filler and rubber, reduce shrinkage and internal stress, prevent crack propagation, and improve the processing performance of product strength.

dolomite powder
 

Glass product

Dolomite and limestone are the third-largest components of glass raw materials except for silica sand and soda ash. In the production of bottle glass, soda ash is the most expensive component. The addition of limestone can partially replace soda ash, but it will have adverse effects. The introduction of magnesium oxide in dolomite can further reduce costs. Dolomite can also provide calcium oxide in the glass industry, adding a soda-ash-silica system to act as a flux. In addition, dolomite can also reduce glass aging, prevent chemical corrosion caused by the atmosphere or moisture, improve the plasticity of colored glass, and increase the strength of glass. Adding a certain amount of dolomite powder to glass can effectively reduce the high-temperature viscosity of the glass and improve the chemical stability and mechanical strength of the product. Practice also shows that the introduction of dolomite powder in the preparation of low-temperature ceramics and float glass ingredients can significantly save energy.

 

Metallurgical industry

Magnesium smelting industry: Dolomite with a raw ore particle size of 30-120mm is an important raw material for the production of metallic magnesium. Its smelting methods are mainly divided into two categories, namely electrolysis, and silicothermic reduction.

Refractories: Dolomite is one of the important raw materials for basic refractories, and its importance is second only to magnesite. It is mainly used for steelmaking converter lining, open-hearth furnace, electric furnace wall, and secondly used for external refining equipment and cement Thermal equipment such as kilns. Dolomite can be made into dolomite brick series (mainly conventional dolomite bricks, zirconium-enhanced dolomite bricks, zirconium-enhanced magnesia dolomite bricks, etc.), fused dolomite carbon bricks, and fused magnesia dolomite carbon bricks.

 

Building Materials Industry

The manufacture of magnesium oxychloride cement is another important use of dolomite. This magnesium-containing cement has good compression resistance, flexural strength, and corrosion resistance. In particular, the caustic powder prepared by muffled calcination of dolomite, and then the magnesium oxychloride cement prepared has a better stability. Magnesium-containing cement has been widely used in floor tiles, fast-setting pavement paving, and repair of pavement cracks. In addition, after calcining dolomite to produce caustic dolomite, it can also be processed into magnesium hydroxide cement and magnesium oxide sulfate cement. These two non-hydraulic cementitious materials have the advantages of the simple production process, fast setting, and hardening, high strength, strong bonding force, good elasticity, wear resistance, convenient molding, low energy consumption, etc., and have high development and use-value.

 

Application in agriculture

Used to neutralize the acidity in the soil. Since long-term use of urea and other fertilizers is easy to cause the soil to be acidic, dolomite can be directly added to the area to keep the soil at an appropriate pH value, which can generally increase crop yields by 15% to 40% and can also improve the efficacy of herbicides. , The herbicide effect is best when the pH is 6.0-6.2. Dolomite can also compensate for the loss of magnesium content in the soil. Dolomite particles of 1.2 ~ 0.8um can flow freely. Used as a filler for fertilizers, it can improve the conditions for plants to use soil nutrients, reduce agglomeration, and facilitate adjustment of fertilizer ratio. In livestock and poultry feed, both calcium and magnesium are essential nutrients in animals. Adding an appropriate amount of dolomite powder to livestock and poultry feed is very beneficial for promoting animal growth and reducing diseases.

 

Application in ceramic production

Dolomite is used in blanks and glazes, and MgO and CaCO3 are introduced to replace talc and calcite. The role of MgO is to change the composition of the mixing system, thereby reducing the firing temperature of the green body; promoting the dissolution of quartz and the formation of mullite, increasing the amount of quartz, and reducing the amount of feldspar, thereby increasing the transparency of the green body. Adding dolomite to the glaze is more difficult to smoke than adding calcite to the glaze, and crystallization rarely occurs. This series of dolomite is caused by double salt minerals. The dolomite limestone mixture made of dolomite and marl can be used to prepare anorthite and diopside-wollastonite clinker, which is suitable for fast-fired porcelain. In the manufacture of wall tiles and fine ceramics, the cost of this clinker is lower than the calcium-magnesium compound synthesized separately.

 

Dolomite is sorted, crushed, and ground into dolomite powder from 325 to 2000 meshes. With the scale of the dolomite powder industry and the upgrading of application requirements, the traditional small-scale and multi-equipment extensive processing mode can no longer meet the market demand. Therefore, the use of new It is imperative to improve the processing scale and technical level of the company’s powder technology and equipment. The CLUM series of ultra-fine vertical mills are the crushing, drying, grading, transportation, secondary powder selection, and finished products developed by Kolyric for many years. A comprehensive mill with six major functions such as packaging can effectively increase the added value of dolomite products. The output of the same product CLUM series ultrafine vertical mills can be increased by 30%.

The dolomite powder processed by the ultrafine vertical mill can be added to natural rubber and synthetic rubber. Its rubber performance is the same as that of light calcium powder, but the cost is lower than that of light calcium powder. Dolomite is used to produce rubber general-purpose calcium-magnesium powder. As a new type of additive and coloring agent, it can partially or completely replace light calcium powder. The surface-modified dolomite powder can greatly increase the reinforcing performance of rubber products. Modified dolomite powder uses a surface modifier to coat the surface of dolomite powder, and then it is used as filler. Commonly used surface modifiers include stearic acid or stearate, titanate, zirconium aluminate, and mixed silane coupling agents. The purpose of the modification is to change the surface alkalinity of dolomite powder, overcome the bonding performance between filler and rubber, reduce shrinkage and internal stress, prevent crack propagation, and improve the processing performance of product strength.

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