Limestone

Calcium carbonate is an inorganic compound with the chemical formula CaCO3 . 

Calcium carbonate can be prepared from slaked lime and calcium chloride. It is insoluble in liquid (water). CaCO3 is present in our surroundings as marbles, corals, chalk, and calcite. To exist as dolomite, it reacts with magnesium carbonate. Calcium carbonate can also be called limestone. 

The following are the uses of calcium carbonate:

• It is used in toothpaste or as an antacid
• The marble form of calcium carbonate is used as a building material
• To make good quality paper, precipitated calcium carbonate is used
• It is also used in cosmetics as filler.

What is limestone? 

Limestone is an ordinary, sedimentary rock made from calcium carbonate. It is usually lightweight material. Limestone is that kind of rock that is found in karst features. It has been used for over centuries for many uses because it is widely obtainable. The Florida Keys and The Niagara Falls are two famous limestone sediments. It is commonly grey, but it can be yellow, white and brown. Limestone is a scratchable stone as it is so soft. It has many textures and is used in a decorative manner. It consists of rich fossil content shell fragments. With the help of living organisms and evaporation, limestone is made chemically. While burning, it gives lime, so it is called limestone.

Types of limestone:

• Ragstone
• Coquina
• Coral rag
• Carboniferous Limestone
• Chalk
• Lithographic limestone
• Oolite
• Shelly limestone
• Travertine
• Fossiliferous limestone

Classification of limestone:

There are two important classifications of limestone. They are:

• Folk Classification:

Robert L. Folk modified the class gadget emphasising the first number in forming grain and interstitial fabric in carbonate rocks. There are three most essential additives based on the composition: allochems, matrix, and cement. Folk Gadget uses feature names; the first refers to the back of the letter and the second to the root. It is helpful to have a petrographic microscope when using the Folk system because it is easy for miles to specify the additives found in every pattern.

• Dunham classification:

The Dunham system is particularly effective in depositional captivity. Each call is based on the sound of the letters that make up the limestone. Robert J. Dunham sent his limestone system in 1962; it is very much focused on the placement of carbonate stones. Dunham divides rocks into 4 key companies based on limited estimates of solid clastic particles. Dunham’s names actually belong to the rock family. His efforts address the question of whether the letters were intertwined or not at first, so as to help themselves, or whether the rock is characterised by the presence of frame developers and algal mats. Unlike the Folk program, Dunham faces the original porosity of the rock. The Dunham system benefits most hand samples because it is based so far on captivity, not grain within the sample.

Formation of limestone:

The development of the limestone market has been very rapid in the Asia Pacific over the past decade, largely due to the presence of developing countries in the region, such as China, which holds the highest market share in the world. Several Asia Pacific countries have seen rapid urban growth over the past few years, which has provided ample room for limestone market expansion.

Europe also showed tremendous growth. The region has a strong presence in the global steel industry. Metallurgy requires a large amount of limestone as raw material, which is thought to drive the limestone market in the region at the time of forecasting. This North American rock market is driven primarily by its demand for agriculture and water treatment.

Properties of Limestone

• With more than 50% of calcium carbonate, limestone is a sedimentary rock
• It is usually light-coloured. It can be yellow, white, and grey
• It is chemically composed of calcite
• Limestone cannot be completely white because it has some impurities
• Acid test is a well-founded test for limestone
• Limestone soaks up all pollutants
• You can see limestone mostly at the ends of marine water.

Uses of Limestone

It is a very special mineral that is used in many ways. Some of the uses are as follows:

• As limestone is calcium carbonate, it is used in industries in the form of flux for the making of steel.
• Portland cement is known to be the product of limestone.
• It is also used in the field of agriculture for neutralising the acidity of soil.
• In limestone preparation, it reacts with sulphur dioxide, which helps in controlling air pollution.
• If limestone is fully purified, then it can be useful for being added in breads and cereals.
• Limestone subdues the methane explosion.
• It is also used in cosmetics as filler.
• As its purified form has white colour, it is used in the making of sculptures.
• Marble is also a form of limestone, which has been used since ancient times for construction.
• The crushed powder of limestone is used as filter stone.

Conclusion

Limestone is generally called calcium carbonate. It can be used as raw material in the manufacture of cement. Limestone is a sedimentary rock in which more than 50% is CaCO3. 

Limestone is also present in marble, used from ancient times for construction work. Quicklime is prepared from limestone. Toothpaste also contains limestone as the main ingredient. Only the unsaturated form of limestone is dissolved in water. It also has some impurities, which results in fading of the colour. We have studied the properties and uses of limestone and learned a bit about calcium carbonate.