What is Dolomite ?

Dolomite is a common rock-forming mineral. It is the primary component of the sedimentary rock known as dolostone and the metamorphic rock known as dolomitic marble. Limestone that contains some dolomite is known as dolomitic limestone.

Dolomite is rarely found in modern sedimentary environments but dolostones are very common in the rock record. They can be geographically extensive and hundreds to thousands of feet thick. Most rocks that are rich in dolomite were originally deposited as calcium carbonate muds that were post-depositionally altered by magnesium-rich pore water to form dolomite.

Dolomite is a double carbonate of calcium and magnesium (CaCO3, MgCO3). It is one of the important raw materials used in the iron and steel, ferro-alloys, glass, alloy steels, fertilizer industry, etc. Dolomite chips are also used in flooring tiles.

Dolomite has a hardness of 3 1/2 to 4 on Mohs hardness scale and is sometimes found in rhombohedral crystals with curved faces.

Dolomite is very similar to the mineral calcite. Calcite is composed of calcium carbonate (CaCO3) while dolomite is a calcium magnesium carbonate (CaMg(CO3)2). These two minerals are one of the most common pairs to present a mineral identification challenge in the field or classroom. The best way to tell these minerals apart is to consider their hardness and acid reaction. Calcite has a hardness of 3 while dolomite is slightly harder at 3 1/2 to 4. Calcite is also strongly reactive with cold hydrochloric acid, while dolomite will effervesce weakly with cold hydrochloric acid.

It is a Calcium magnesium carbonate with a chemical composition of CaMg(CO3)2.

Synonyms of Dolomite includes Marble, Limestone, dolostone etc.

Dolomite properties:  Dolomite produces a very weak reaction to cold, dilute hydrochloric acid; however, if the acid is warm or if the dolomite is powdered a much stronger acid reaction will be observed. (Powdered dolomite can easily be produced by scratching it on a streak plate.) This makes it a very essential mineral in our day-to-day life.

 

Dolomite has an enormous number of uses, like :

  1. The most common use for dolomite is in the construction industry. It is crushed and sized for use as a road base material, an aggregate in concrete and asphalt, railroad ballast, rip-rap or fill. It is also calcined in the production of cement and cut into blocks of specific size known as “dimension stone”.
  1. Dolomite’s reaction with acid also makes it useful. It is used for acid neutralization in the chemical industry, in stream restoration projects and as a soil conditioner.
  1. Dolomite is used as a source of magnesia (MgO), a feed additive for livestock, a sintering agent and flux in metal processing and as an ingredient in the production of glass, bricks and ceramics.
  1. Dolomite is used in iron and steel industry as refractory raw materials and a flux.
  1. Dolomite serves as the host rock for many lead, zinc and copper deposits. These deposits form when hot, acidic hydrothermal solutions move upward from depth through a fracture system that encounters a dolomitic rock unit. These solutions react with the dolomite which causes a drop in pH that triggers the precipitation of metals from solution.
  1. Dolomite also serves as an oil and gas reservoir rock. During the conversion of calcite to dolomite a volume reduction occurs. This can produce pore spaces in the rock that can be filled with oil or natural gas that migrate in as they are released from other rock units. This makes the dolomite a reservoir rock and a target of oil and gas drilling.

 

Dolomite Chemical Properties/Composition :

CaCO3 : 56.5%
MgCO3 : 43.0%
CaO : 31.5%
MgO : 20.5%
Fe2O3 : 0.5%
SiO2 : 1.5%
Al2O3 : 0.5%

 

Dolomite Physical Properties :

Appearance : White Crystalline Powder.
Sp. gravity : 2.6 – 2.8
Oil absorption : 12 to 14
Volatile content : Max. 0.5%
PH of 10% slurry : 8.5 to 9.0
Coarse Particles : Max. 0.5%

 

Dolomite Industrial Applications & Uses :

1. Paints : Used widely in cement paints, exterior paints, primers, putties, powder coatings and industrial finishes.
2. Plastic : Used in PVC footwear, PVC pipes, cables and others.
3. Paper : Used as integral filler in paper to give smoothness and gloss.
4. Adhesives : Used in adhesives and carpet backing.
5. Rubber : It is used in toothpaste, cosmetic and soap industry.
    1. Glass
: High-grade dolomite with as low content as possible is required by the glass industry. Glass grade dolomite is typified by its purity and consistency.
    1. Fertilizer
: Dolomite for use in fertilizer industry must have CaCO3 + MgCO3 90% (min.) and SiO2 5% max.

Dolomite  Price in India (Our suggested Dolomite grades):

Dolomite Grades / Model no. VD – 96H13 VD – 96H15 VD – 90M200 VD – 95CF13 VD – 90CR20
Product Name Premium Quality Dolomite powder High Grade Dolomite powder Dolomite powder as filler Coated Dolomite Powder (1%) – I Coated Dolomite Powder (1.5 %) – II
Whiteness/Brightness (%) 96% 95% 90% 95% 90%
Moisture (%) 0.5 max 0.5 max 0.5 max 0.5 max 0.5 max
Specific Gravity (g/cm3) 2.6 – 2.8 2.6 – 2.8 2.6 – 2.8 2.6 – 2.8 2.6 – 2.8
Oil Absorption 34-36 34-36 34-36 34-36 34-36
Particle Size 13 micron 15 micron 200 mesh 15 micron 20 micron
Top cut 30 micron 40 micron 500 mesh 40 micron 40 micron
CaCO3 (%) 54% – 56% 54% – 56% 52% – 55% 54% – 56% 52% – 55%
MgCO3 (%) 40% – 42% 38% – 40% 30% – 32% 38% – 40% 30% – 32%
SiO2 (%) 4% – 6% 8 – 10% 8 – 10% 8 – 10% 8 – 10%
Fe2O3 (%) 2% 2% 2% 2% 2%
Al2O3(%) 14% – 16% 15% – 16% 15% – 16% 15% – 16% 15% – 16%
LOI 45% – 47% 45% – 47% 42% – 45% 45% – 47% 42% – 45%
Applications Ceramics, Plastics, Detergents & Paints Plastics & paints industry; Ceramics Ideal for detergents and soaps Paints and Plastics industry Paints and Plastics industry

For various applications we also manufacture & supply tailor made Dolomite as per customers’ demand.

Packaging & Delivery Details:
Packaging: 50 kg pp bag; 1ton/bag; 1*20 container, can load 25-27 MT or upon clients’ requirement
Delivery: within 5 – 20 days (depending upon the delivery location) after receiving the deposit