Important Topic: Limestone

 

Introduction

Limestone is a type of sedimentary rock that is naturally found in the earth’s crust. The rock is composed mainly of a chemical composed of calcium carbonate (CaCO₃) in the form of calcite which is a type of mineral. It also contains other substances such as quartz, clay minerals, pyrite, feldspar, and siderite among others.

When it comes to concrete structures, limestone usually differs between fine-grained stone and solid rock. In addition, there are many different types and names of limestone such as chalk, coquina, travertine, tufa, fossiliferous limestone, lithographic limestone, oolitic limestone. They have been classified according to the shape of each rock, its appearance, shape, and other factors.

Different Use of Limestone

When we talk about the use of limestone, the first thing that comes to our mind

Construction. However, buildings (or construction) are one area where they rely heavily on limestone. Interestingly, since this rock is precious and valuable, buyers are willing to pay even five times more than the price of a stone, especially for delivery. However, apart from buildings, there are a few other uses for this rock. We will take a closer look at them.

• Agriculture
• Industries
• Construction and Architects
• Other Uses

Agriculture

We have already mentioned that limestone deposits contain mainly calcium carbonate compounds. Therefore, this ingredient can be celebrated for use in the agricultural sector. Generally, limestone is ground into smaller particles and various grades are produced. Finally, these products are marketed as ‘agricultural lime or“ Aglime ”which is also used to reduce soil acidity and release minerals in the soil such as phosphates.

Industries

There are several industries that use limestone. Thus, powdered limestone is used in the textile, paint, paper, rubber, glass and plastic industries, among others. They are widely used as fillers. Apart from this, it is used in the steel industry in the production process where limestone is used to remove impurities. Minerals found in limestones are also used in pharmaceuticals, cosmetic products, baking soda, toothpaste, etc.

Construction and Architects

Here limestone is mined to meet the needs of the construction and construction industries. So the stone is cut into slabs or blocks of a certain size. Some of its features include recorders, floor tiles, windows, stairs, and more. The famous pyramid of Giza in Egypt is made of limestone.

In addition, limestones containing clay are used in the production of cement. Limestone aggregate is also used in road and rail construction.

Other Limestone Uses

Crushed limestone is used as a filter in site waste disposal systems. Powdered limestone is also used as a dehumidifier or to control coal mine dust in many coal mines. Lime limestone is used to make acidic acids and to purify wastewater, industrial mud, animal waste, and water supplies.

Commercial Production of Calcium Carbonate

Calcium carbonate is commercially produced in two different grades. Both industries compete for industry primarily in terms of particle size and product characteristics.

• Ground Calcium Carbonate – Produced by extracting and processing natural deposits. The crystalline structure of the GCC is irregularly rhombohedral and has a wide distribution.
• Precipitated Calcium Carbonate – Produced by chemical precipitation by the process of carbocation or as a by-product of certain chemical processes. PCC crystal shape depends on the product and the product and the particles are very similar and common in small size distribution.
• PCC has smaller particles with higher purity which is less harmful and tends to have higher light than GCC.

Calcium Carbonate Formula

• It is a chemical compound with the chemical formula CaCO3.
• It is similar to the insoluble white powder found naturally in minerals, chalk, marble, limestone, calcite, shells, pearls, etc.
• Medically, it is used as an antacid or as a calcium supplement. It is also used as fillers in cosmetics. Added to swimming pools as a disinfectant and as a pH corrector.
• It is widely used in the manufacturing industry such as building materials (marble), quick-mixing mortar and cement.

Preparation of Calcium Carbonate – CaCO₃

1. CaCO₃ is obtained by using carbon dioxide and slaked lime as raw materials. When carbon dioxide passes through slaked lime, calcite is found.

Another way to obtain calcite is by adding sodium carbonate to calcium chloride.

Ca (OH)₂ + CO₂ → CaCO₃ + H₂O

CaCl₂ + Na₂CO₃ → CaCO₃ + 2NaCl

Excess carbon dioxide leads to the formation of calcium hydrogen-carbonate.

2. To a large extent, it is prepared by transferring carbon dioxide gas with calcium hydroxide (slaked lime). However, when carbon dioxide is excessive, it forms a soluble calcium hydrogen-carbonate.

Ca (OH)₂ + CO₂ → CaCO₃ + H₂O

Structures of Calcium Carbonate – CaCO3

Soft powder.

It decomposes to provide carbon dioxide when it heats up to 1200K.

When it reacts with dilute acid, it releases carbon dioxide as a by-product.

CaCO₃ + H₂SO₄ → CaSO₄ + H₂O + CO₂

At 1200K, calcium carbonate decomposes to provide carbon dioxide and calcium oxide.

CaCO₃ → CaO + CO₂

In reaction with dilute acid, calcium carbonate releases carbon dioxide.

CaCO₃ + 2HCl → CaCl₂ + H₂O + CO₂

Use of Calcium carbonate

Calcium carbonate is widely used in the pulp and paper industry. It can be used as a filter and pigment, which facilitates the production of white pigment, which is much higher than other minerals.
In the construction industry, calcium carbonate is used as a concrete filler, which increases the strength and visibility and refinement of metals for use in construction projects.
Other uses of calcium carbonate in fertilizers to provide calcium to plants and stabilize soil pH.
Calcium carbonate can be a supplement to animal and human food products and can also be a vitamin supplement.
In water and sanitation plants, calcium carbonate is used to remove acid and impurities.

Consumption of calcium carbonate

A list of calcium carbonate consumption is given below.

• It plays an important role in construction, either as a building material (marble) or as an ingredient in cement.
• It is used in medical industries that produce antacids, tablets made from basic ingredients etc.
• It is used as a calcium supplement.
• Used in making paints, paper, plastics, etc.

Limestone is a common type of sedimentary carbonate rock. It is mainly composed of the minerals calcite and aragonite, which are different types of calcium carbonate crystals. Limestone is formed when these minerals come out of water containing dissolved calcium.

FAQ’s

What is calcium carbonate used for?

Used as antacid calcium carbonate to relieve heartburn, acid indigestion, and stomach upset.

Name a fruit rich in calcium?

Apricot, celery, figs, dried calcium-rich fruit.

Is Limestone calcium?

A sedimentary carbonate rock that often contains bone fragments of marine organisms such as coral, foraminiferous, and molluscs.

How do you identify carbonate salt?

Solid acids, such as hydrochloric acid, may be added to test whether a mineral or rock contains calcium carbonate. If the sample contains calcium carbonate, carbon dioxide will be immersed and produced.