What is Calcium Carbonate?
Calcium carbonate is a chemical inorganic compound having the chemical formula CaCO3.It is also one of the most popular chemicals which is encountered first in school classrooms, where the use of chalk (which is a form of CaCO3) is found. It is found in the crust of the earth. It is available in various forms, such as limestone, marble, and more. Although they are available in different forms, they are chemically similar and differ only physically. They are also called calcite. The symbol of calcium carbonate can be given as CaCO3.
Types of Calcium Carbonate found in the Environment
Calcium carbonate is present in three polymorphic forms - calcite, aragonite and vaterite.
Calcite: It is the most stable and the least soluble. A rock-forming mineral, it is commonly found in sedimentary, metamorphic, and igneous rocks. Calcite is a common constituent of sedimentary rocks like limestone and marble. It is used extensively in construction material, agricultural soil treatment, pharmaceuticals and many more areas.
Argonite: It is less stable and more soluble than calcite. It is formed by biological and physical processes, including precipitation from marine and freshwater environments. Aragonite provides ingredients to sea life, and also maintains the pH levels to its natural level. It is used to remove pollutants like zinc, cobalt and lead from contaminated wastewaters.
Vaterite: Hexagonal in shape, vaterite, is less stable than calcite and aragonite, with a higher solubility. It is found naturally in springs, organic tissue, urinary calculi, gallstones, and plants. It finds its uses in regenerative medicine and a range of personal care products.
CaCO3 Structure
Calcium carbonate is odorless, and a non-toxic compound found commonly as a white mineral that occurs naturally in limestones, chalks, and marbles.
The Calcium Carbonate structure can be given as follows:
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Calcium Carbonate Formula
Calcium Carbonate is a chemical compound having the chemical formula CaCO3.
It is a white and insoluble powder-like substance that occurs naturally in minerals, marble, chalk, limestone, shells, calcite, pearl, and other related compounds.
Medicinally, we use it as an antacid or a calcium supplement. It can also be used as cosmetics fillers. It is added to swimming pools as a disinfectant agent and also as a pH corrector.
We can find it in extensive usage in the manufacturing industry as an ingredient for quick lime and cement and building material (marble).
Preparation of CaCO3
CaCO3 is obtained mainly by using slaked lime and carbon dioxide as raw materials. When carbon dioxide compound is passed through slaked lime, calcite is obtained.
There is also another method to obtain the calcite by adding sodium carbonate to calcium chloride.
CaCl2 + Na2CO3 → CaCO3 + 2NaCl
Ca (OH)2 + CO2 → CaCO3 + H2O
When carbon dioxide is passed in excess amounts, it leads to the formation of calcium hydrogen-carbonate.
It can be prepared on a large scale by passing carbon dioxide gas through calcium hydroxide (otherwise called slaked lime). However, if there is an excess passing of carbon dioxide, it results in the formation of soluble calcium hydrogen-carbonate.
Ca(OH)2 + CO2→ CaCO3 + H2O
Commercial Production of Calcium Carbonate
Calcium carbonate can be produced commercially in two different grades. Both these grades compete industrially primarily based on the particle size and the characteristics that are imparted to a product.
Ground Calcium Carbonate - It is produced via extraction and processing naturally occurring deposits. The GCC crystal shape is irregularly rhombohedral, and its distribution is a broader size.
Precipitated Calcium Carbonate - This is produced via chemical precipitation with a carbocation process or as a by-product of a few bulk chemical processes. The shape of the PCC crystal depends on the product, and the particles are more regular and uniform with a distribution of narrow size.
PCC has smaller particles that have higher purity, are less abrasive, and tend to have higher brightness than GCC.
Physical Properties of CaCO3
Calcium Carbonate is a fluffy powder.
It decomposes to form carbon dioxide when heated up to 1200K.
It liberates carbon dioxide as a by-product when it reacts with dilute acid.
At a temperature of 1200K, calcium carbonate decomposes to form calcium oxide and carbon dioxide.
While reacting with dilute acids, calcium carbonate produces carbon dioxide.
The molecular weight of CaCO3 100.0869 g/mol.
The molecular mass of calcium carbonate is 100.0869 g/mol.
Application of Calcium Carbonate
Calcium carbonate is employed largely in the paper and pulp industries. It can also be used as a pigment and filter, making possible the production of a whiter and higher quality pigment compared to other minerals.
Calcium carbonate is used in the construction industry as a filler in concrete, increasing its appearance and durability and purifying metals to use in construction applications.
The other application of calcium carbonate is in fertilizers in providing calcium to plants and pH stabilization of the soil.
It can also be an additive to food products for humans and livestock animals and as a vitamin supplement.
Calcium carbonate is employed in water and sewer treatment plants in the removal of impurities and acidity.
Calcium Carbonate Uses
The uses of calcium carbonate are listed as follows:
Calcium Carbonate plays an important role in the construction department, whether as an ingredient in cement or as a building material (marble).
It can be used in medicinal industries in the manufacturing of calcium dietary supplements, pharmaceutical filler in tablets, and antacids, which are made of base materials.
It can also be used in the manufacturing of paper, paints, plastics, and more.
It is used as calcium supplements.
It is used to make building materials like ceramic tiles
Blackboard chalk.
Iron ore purification,
Oil well drilling fluids.
Paints, adhesives, and sealants.
It is used in hemodialysis treatment.
It finds its use in food preservatives and toothpaste.
It is used in refining sugar from sugar beet.
It is often added to swimming pools, as a pH corrector to maintain alkalinity.
In agriculture, it is used to maintain the right acidity of soil and supply calcium that the growing plants require.
Other Important Information
If this medicine or compound has been prescribed for you, keep all the appointments with your doctor so that your response to this compound can be checked. And, do not let anyone else take your medicine.
It is also important for you to keep a written list of both prescription and nonprescription (over-the-counter) medicines you are taking and also any products, including minerals, vitamins, or other dietary supplements. Besides, you should carry this list with you every time you visit a doctor or if you get admitted to a hospital. It is also important to carry this with you in case of emergencies.
Interesting Facts
It is said that Cleopatra used to dissolve pearls made of calcium carbonate in vinegar and drink the solution, as part of her extravagance.
Stalagmites and stalactites are formed when calcium bicarbonate dissolved in the groundwater reaches the top of a cave and loses carbon dioxide (CO2). When calcium bicarbonate gives up CO2, it gets converted into calcium carbonate, which precipitates on the roof to form a stalactite. When the calcium bicarbonate does not lose the carbon dioxide before dripping down and falling on the floor, the calcium carbonate builds up to form a stalagmite on the floor instead.
Calcium Carbonate is used to counter the increased acidity in lakes and other water bodies, and purify water and wastewater, and treat waste gases by removing sulfur and nitrogen oxides that pollute the air.
FAQs on Calcium Carbonate
1. How should Calcium Carbonate Medicine be used?
Calcium carbonate can resultantly be formed as a chewable tablet, tablet, capsule, and a liquid to take by mouth. Usually, it is taken three to four times a day. But, one should carefully need to follow the directions on the prescription or package label and ask the pharmacist or doctor to explain any part you do not understand.
You should take this compound exactly as directed. Do not take either less or more of it. Instead, take it more often than prescribed by your doctor. Take It is better to take it with food or the following meals when using this medicine as a dietary supplement.
Do not take this compound as an antacid for more than 2 weeks until or unless your doctor tells you to use
2. What Special Precautions should be followed before taking Calcium Carbonate?
Before going to take calcium carbonate,
Tell your pharmacist and doctor if you feel allergic to calcium carbonate or to any other drugs.
Tell your pharmacist and doctor about the prescription and nonprescription medications you are taking, especially etidronate (Didronel), digoxin (Lanoxin), tetracycline (Sumycin), phenytoin (Dilantin), and vitamins.
Tell your doctor if you have ever had stomach conditions or kidney disease.
Tell your doctor if you are planning to become pregnant, or pregnant, or are breast-feeding. Also, if you become pregnant while taking this calcium carbonate compound, it is better to call your doctor.
3. How is Calcium Carbonate Obtained?
Calcium carbonate is naturally present in several mineral forms. It is mainly obtained from natural sources by mining and processing. Geologically, the pure calcium carbonate minerals are calcite, aragonite and vaterite. Limestone, chalk, marble and travertine are also predominantly calcium carbonate and are the main source of calcium carbonate industrially.
Biologically, it is obtained from corals, clamshells, eggshells, snail shells and most seashells. Oyster shells are used as a source of dietary calcium in industrial use. Dark green vegetables such as broccoli and kale contain significant amounts of calcium carbonate in the diet.
Beyond the earth, evidence suggests that calcium carbonate is present on Mars.
It is also prepared by chemical synthesis by a reaction between quicklime (calcium oxide) and water to give calcium hydroxide (Ca(OH)2). This is further treated with carbon dioxide to produce the calcium carbonate salt.
4. What are the Properties of Calcium Carbonate?
Physical Properties:
Pure CaCO3 is an odorless fine white powder.
It has a density of 2.71 g/mL.
Its melting point is 1,339 °C
The common mineral form, aragonite, has a density of 2.93 g/mL and a melting point of 825 °C. The gravity of the calcite form is 2.71.
It is insoluble in water.
Stable at normal temperatures.
When heated to high temperatures, it decomposes to form calcium oxide (CaO) and carbon dioxide gas (CO2).
Calcium carbonate has two main crystalline forms, with two different geometric arrangements of the calcium and carbonate ions - aragonite and calcite.
It also reacts vigorously with acids to release a froth of carbon dioxide bubbles.
5. What are the Medicinal and Dietary Uses of Calcium Carbonate?
Calcium carbonate is widely used medicinally as an inexpensive dietary calcium supplement for gastric antacids.
It is used as a phosphate binder for the treatment of hyperphosphatemia, primarily in patients with chronic kidney failure.
In pharmaceuticals, it is used as an inert filler for tablets.
It is to produce calcium oxide for toothpaste.
It is used as a food preservative and colour retainer in fruits like organic apples, pears etc.
It also finds a therapeutic use as a phosphate binder in patients on haemodialysis and in non-dialysis chronic kidney disease.
It is also found in fortified food and milk.
It is used as an acidity regulator, anticaking agent and stabilizer.
It is used in some soy milk and almond milk products as a source of dietary calcium.
It is also used as a firming agent in many canned and bottled vegetable products.
A lot of times, Calcium carbonate is formed in sea-water when calcium ions dissolved in minerals react with the dissolved carbon dioxide. The calcium carbonate formed in this way is insoluble in water and sinks to the bottom.
In pearls, which mollusks make the individual CaCO3 crystals are invisibly small, even under a microscope. But they are laid down in such a perfect order that the result is smooth, hard, shiny, and sometimes even iridescent, as in the rainbow colors of abalone shells.
In many cases, the mollusk makes its shell by laying down alternating layers: calcite, aragonite, calcite, aragonite, and so on.
