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Calcium Carbonate

Also known as limestone

CHEMICAL NAME:
Calcite
IMA SYMBOL:
CaCO3
ROCK TYPE:
Sedimentary
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WHAT IS
Calcium Carbonate?

Calcium carbonate is a chemical compound. It occurs naturally in three mineral forms - calcite, aragonite and vaterite. Calcite is the most common form and is the chief component of limestone. Ground Calcium carbonate (GCC) is a white powder produced by grinding limestone Calcium carbonate and is used in many industrial applications such as flooring, roofing, decking and vinyl siding, film and food packaging, adhesives, coatings and many more.

PHYSICAL AND CHEMICAL PROPERTIES

Ground Calcium carbonate is a white, odorless powder, practically insoluble in water. GCC decomposes into calcium oxide and carbon dioxide when heated to high temperatures.

Covia’s HIFILL® grades vary in chemical and physical properties depending on the limestone source and the intended use. Each product is engineered to meet exact specifications.

CaCO3 content: 92.5% or greater

Median particle sizes: 1.95 μ to 12.5 μ

Hardness: 3 on Mohs scale

Moisture content: <0.2%

Specific gravity: 2.7 g/mL

Brightness: 67 to 96.7 GEB

Oil absorption: 19 to 25 g/100 g

Where does Calcium carbonate
Come From?

Calcium carbonate is produced from natural limestone, a sustainable resource that comprises about 15% of the Earth’s sedimentary crust. Covia has two facilities that process limestone into HIFILL ground calcium carbonate (GCC) filler: one in Huntingburg, Indiana, and the other in Apodaca, Nuevo Leon, Mexico.

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Planning /
Geology

Covia’s production facilities receive limestone from nearby quarries. The calcium carbonate stone is ground into a fine powder at these Covia plants. Stones enter the rolling mill and are pulverized, passing through the machinery repeatedly until reduced to the appropriate particle size. An integrated drying system uses heat to dry the resulting powder to meet customer specifications.

Ground calcium carbonate is dried to reduce the moisture content to below 0.2%. The powder is classified to meet the target particle size and stored in silos before being bagged or shipped. Covia's Calcium carbonate product, HIFILL, is produced in multiple grades with varying median particle sizes, from 1.95 μ to 12.5 μ. The final product is shipped in 50-lb bags or by the truckload in pneumatic tankers. 

During processing, the team regularly tests the product for particle size and moisture content to ensure consistency and quality. All HIFILL grades are processed strictly according to Covia QIPSM statistical and quality assurance programs. This results in chemical purity and consistently uniform particle size distributions, which ensure predictable results and reliable service.

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Mythbusters

Marble and limestone are completely different

There’s a misconception that marble and limestone are unrelated. However, marble is a metamorphic rock that forms when limestone is subjected to heat and pressure through natural processes.

Limestone always forms in oceans

A common misconception is that all limestone originates from marine environments. While most limestone forms from marine sediments, some are formed through non-marine processes, such as the precipitation of Calcium carbonate in freshwater caves, which leads to stalactites and stalagmites.

Calcium carbonate is "Just Chalk"

While chalk is a form of Calcium carbonate, not all Calcium carbonate is chalk. Calcium carbonate exists in many forms, including marble, limestone, and even shells of marine organisms. Each form has unique properties and uses.

Applications /
Markets

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Fascinating
Facts

Calcium carbonate is frequently used as an antacid to relieve heartburn, indigestion or other forms of upset stomach, by reducing the amount of acid in the stomach. Another common use is as a Calcium supplement for those with low Calcium levels.

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Fascinating
Facts

The double refraction of Calcite is mystical.

The optical property of double refraction (splitting light into two paths) in Calcite once mystified people and was attributed to magical or supernatural causes. Now, we know it’s due to the crystal’s anisotropic structure.

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Covia’s Calcium carbonate?

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