Calcium Carbonate

Introduction

$\mathrm{CaCO_{3}}$ is found within oyster shells. It’s found in naturally occurring forms such as aragonite, vaterite, & calcite, & industrial forms such as limestone, marble, chalk, & travertine, & oyster shells.

It's an active component in agricultural lime, which is formed when calcium ions combine with carbonate ions in hard water to generate lime scale. It has medicinal use as a calcium supplement or an antacid, but excessive ingestion can be harmful & lead to bad digestion.

What is Calcium Carbonate?

It's an inorganic complex with the formula $\mathrm{CaCO_{3}}$. It's a chemical complex that is among the first chemical compounds seen in classrooms where chalk is commonly used. It may also be found in a variety of different materials, such as marbles & limestone. Although they are accessible in several forms, they are chemically similar & only differed physically. It's a well-known non-toxic & odourless substance that occurs naturally as a white mineral in lime stones, chalks, marbles, & pearls.

Types of Calcium Carbonate Found in the Environment

• Calcite is the most stable & least soluble of the minerals. It's a mineral that forms rocks & is widely found in sedimentary (such as limestone & marble), metamorphic, & igneous rocks. It's widely utilised in construction materials, agricultural soil remediation, medicines, & a variety of other applications.

• Argonite is more soluble & less stable than calcite. It’s created because of biological & physical processes, such as precipitation from marine & freshwater settings. Aragonite offers nutrients to sea life while also keeping pH levels at their normal range. It's employed in the removal of contaminants such as zinc, cobalt, & lead from polluted wastewater.

• Vaterite is a hexagonal mineral that is less stable than calcite & aragonite but has a higher solubility. Natural sources include springs, organic tissue, urinary calculi, gallstones, & plants. It's utilised in regenerative medicine & a variety of personal care items.

Calcium Carbonate Structure

$\mathrm{CaCO_{3}}$ is made up of 2 types of ions − $\mathrm{(Ca)^{2+}\:\&\:(CO_{3})^{2-}}$, which have an ionic connection. Furthermore, the triangular planar structure of the carbonate ion is visible.

Calcium Carbonate Formula

It is an inorganic complex with the formula $\mathrm{CaCO_{3}}$. It's a white powdery component found in minerals, shells, chalk, calcites, marble, pearls, limestone, etc.

Preparation of Calcium Carbonate

• It's made by combining $\mathrm{CO_{2}}$ & slaked lime as source components. Another way for creating calcite is to combine sodium carbonate with calcium chloride.

$$\mathrm{CaCl_{2}\:+\:Na_{2}CO_{3}\:\rightarrow\:CaCO_{3}\:+\:2NaCl}$$

$$\mathrm{Ca(OH)_{2}\:+\:CO_{2}\:\rightarrow\:CaCO_{3}\:+\:H_{2}O}$$

• Calcium hydroxide is used to bypass the $\mathrm{CO_{2}}$ gas during large-scale processing. If there is an excess of $\mathrm{CO_{2}}$, it produces soluble calcium hydrogen carbonate.

$$\mathrm{Ca(OH)_{2}\:+\:CO_{2}\:\rightarrow\:CaCO_{2}\:H_{2}O}$$

Commercial Production of Calcium Carbonate

There are 2 types of commercial production. Both classifications of particles perform industrially based on particle size & product attributes.

• The extraction & processing of naturally existing deposits yield ground calcium carbonate. The GCC crystal has an irregular rhombohedral form & a larger size dispersion.

• Precipitated $\mathrm{CaCO_{3}}$ is produced by a chemical precipitation process aided by a carbocation procedure. The product influences the structure of the PCC crystal, & the substances are more uniform & homogeneous with a narrow distribution size. PCC contains smaller, purer particles, is less abrasive, & has a higher brightness than GCC.

Physical Properties of Calcium Carbonate

Property	Value
Appearance	Fluffy powder
Molecular weight	100.0869 𝑔/𝑚𝑜𝑙
Odour and taste	Odourless & tasteless
Density	2.71 𝑔/𝑐𝑚3
Solubility in water	low
Solubility in dilute acid	soluble

Application of Calcium Carbonate

• The paper & pulp industries rely heavily on calcium carbonate.

• It's also utilised in fertilisers to provide calcium to plants & to keep soil pH stable.

• It can also be utilised as a vitamin supplement & an ingredient in food items for people & farmed animals.

• In water & wastewater treatment plants, $\mathrm{CaCO_{3}}$ is utilised to remove pollutants & acidities.

Calcium Carbonate Uses

• When the amount of calcium in the diet is low, it’s taken as a nutritional supplement.

• It's utilised to separate iron from iron ore.

• It's utilised in the sugar refining process.

• In agriculture, it's utilised to neutralise acidic soil.

• It's utilised in home cleaning powders as a scrubbing agent.

• It's utilised in building & road construction.

Interesting Facts

• As part of her extravagance, Cleopatra is claimed to have dissolved pearls made of $\mathrm{CaCO_{3}}$ in vinegar & drank the solution.

• When calcium bicarbonate dissolved in groundwater reaches the roof of a cave & loses carbon dioxide, stalactites & stalagmites develop. When calcium bicarbonate emits $\mathrm{CO_{2}}$, it's transformed into calcium carbonate, which forms stalactites on the roof. When calcium bicarbonate does not shed the $\mathrm{CO_{2}}$ before trickling down & landing on the floor, it builds up on the floor to create a stalagmite.

• It's utilised to reduce acidity in lakes & other bodies of water, filter water, and wastewater & treat waste gases by eliminating sulphur & nitrogen oxides that contaminate the air.

Conclusion

Calcium carbonate may be found all around the world, from pearls deep in the ocean to chalkboards in classrooms. It's a white, odourless powder that may be found all over the planet. It makes up 4% of the Earth's crust & may be found in limestone, chalk, & marble. These shapes are the result of millions of years of deposition of fossilised shells of snails & shellfish. Throughout history, man has been found $\mathrm{CaCO_{3}}$ to be a highly valuable substance. It's a very helpful ingredient that can be found all over the world & has helped humanity evolve.

FAQs

1. How do we recognise carbonate salt?

When a strong acid, such as 𝐻𝐶𝑙 or $\mathrm{H_{2}SO_{4}}$, is added to a sample containing $\mathrm{CaCO_{3}}$ or any carbonate salt, it produces fizz or effervescence. This is due to $\mathrm{CO_{2}}$ emissions.

$$\mathrm{CaCO_{3}(s)\:+\:2HCl(aq)\:\rightarrow\:CaCl_{2}(s)\:+\:H_{2}O(aq)\:+\:CO_{2(g)}}$$

2. What are some natural $\mathrm{CaCO_{3}}$ sources?

It’s found naturally in eggshells, snail shells, seashells, & pearls. It's also a component of dark green vegetables, which contain high levels of calcium carbonate. It's widely utilised in calcium supplements & antacids in medicine.

3. When a sample of $\mathrm{CaCO_{3}}$ is utilised for a flame test, the resulting flame colour is?

The flame test is an analytical method for detecting the presence of certain metal ions. It includes 𝐶𝑎2+, which gives the flame a brick red colour.

4. Make a list of calcium-rich foods that you eat daily?

Calcium is found in a variety of foods that we consume regularly. Calcium-rich foods include broccoli, kale, soybeans, figs, oranges, apricots, almond milk, raisins, cereals, tofu, sardines, shrimps, & dairy products such as yoghurt, milk, & cheese.

5. Is $\mathrm{CaCO_{3}}$ basic or acidic?

It's a salt of a strong base & weak acid, because of the existence of the calcium ion. As a result, this salt is somewhat basic.