What are the major uses of gypsum in construction medicine and manufacturing
Gypsum is a type of soft sulfate mineral known for its usefulness in day-to-day lives. It is also referred to as calcium sulfate dihydrate. It consists of water, calcium sulfate and oxygen molecules and is chemically represented by the formula CaSO4.2H2O. An evaporite mineral, gypsum is mostly found in layers of sedimentary rocks on the earth’s crust along with other minerals such as calcite, dolomite, etc. Gypsum finds a wide range of applications in the manufacturing sector. It is used in the construction of building parts, in sculpture and also as a fertilizer in agriculture. To know about the various uses of gypsum, you must, first, know about its formation, properties and other features.
Gypsum Formation
Gypsum is a non-metallic natural mineral. Millions of years ago, there was a time when oceans covered the maximum part of the earth’s surface. Those were the magnanimous repositories of salt. As they started to recede, inland “dead” water bodies began to form which started to become saltier with further evaporation. Thus, with the precipitation of these salts, many compounds came into existence, among which gypsum was one.
Physical Properties of Gypsum
Gypsum is either colourless or white but due to the presence of impurities, it appears to be tinted light brown, grey, yellow, green or orange. It has a silky texture with a sugar-like appearance. Gypsum is found in various forms. Well developed, monocrystals are mostly blocky with slanted outlines whereas doubled crystals commonly form fishtail characteristics.
The physical properties that distinguish gypsum from other minerals are:
Gypsum ranges from transparent to translucent.
Gypsum comes in varieties such as “satin spar” and “alabaster.”
The mineral is soft and feels rather light
Small crystal-like forms appear pearly, whereas the massive ones look dull.
Important uses of Gypsum
Gypsum is a non-toxic mineral that is available in various forms. Due to its wide range of variety, it is considered useful in many fields. For example, alabaster is one variety of gypsum that is widely used by sculptors in Egypt and Mesopotamia. It is also used in the production of plaster of Paris, which is also known as Gypsum Plaster. It is usually obtained by heating gypsum to a temperature of about 300-degree Fahrenheit.
While the majority of gypsum is produced in North America in the construction of gypsum panel products, it is also helpful to humans, plants and the environment. Some other major uses of gypsum are:
It is used as a component of cement for controlling the force at which concrete sets in.
Due to its low thermal conductivity, it is used in the manufacturing of drywall or wallboards.
The alabaster form of gypsum mineral is also used for ornamental purposes as well as in the production of items that are made using plaster of Paris. It also helps to prevent cracks in the gypsum wallboard-combined compounds.
Gypsum use in Agriculture
Gypsum plays an important role in the agricultural sector. It acts as a soil additive and fertilizer. The mineral consists of two main ingredients necessary for healthy plant growth - calcium and sulphur. While calcium helps to absorb nutrients via the roots, sulphur improves the overall production of crops. Gypsum as a soil quality booster also controls excess salinity of the soil by removing sodium from it.
Besides, gypsum facilitates the proper growth of the roots by helping in the easy movement of air and water through it that is absorbed from the soil. By doing so, gypsum strengthens the roots and prevents soil erosion. The mineral also balances soil micronutrients such as iron and zinc
What is Gypsum used for - The Other Uses
Gypsum has a reasonably high binding and thickening capacity due to which it is used in shampoos and hair care products. It is also used as an insulator.
Needless to say, with all the above-mentioned details it is quite evident that gypsum is one of the most valued minerals with endless applications in human lives. With a specific gravity of 2.3 to 2.4, gypsum mining is quite simple and easy, as the mineral is available in large quantities near the earth’s surface. Another advantage of this mineral is that it can also be recycled.
Interesting Facts about Gypsum
Gypsum is a rare mineral that is known for its flexibility. It can be grounded into a fine powdery form and also can be boiled at a certain temperature until all its moisture gets removed totally through a process called calcination.
One can easily shape/mould gypsum by adding water to the powdery form. That is why it is used widely in sculpting.
Gypsum is an important ingredient of toothpaste.
Another interesting fact regarding gypsum mineral is that before the era of technical effects, filmmakers used a lot of products to create artificial snow including cotton and many other substances. They also used shaved gypsum to mimic real snow on the films’ sets.
FAQs on Uses of Gypsum and Its Industrial Importance
1. What is gypsum and what is its chemical formula?
Gypsum is a naturally occurring hydrated calcium sulphate mineral with the chemical formula CaSO4·2H2O. It consists of:
- One calcium ion (Ca2+)
- One sulphate ion (SO42-)
- Two molecules of water of crystallisation
Gypsum is widely used in construction, agriculture, cement manufacturing, and for making plaster products due to its soft nature and ability to lose and regain water.
2. What are the main uses of gypsum in construction?
Gypsum is mainly used in construction for making plaster, drywall, and cement retarders.
- Production of Plaster of Paris (CaSO4·½H2O)
- Manufacture of gypsum boards (drywall sheets)
- Added to Portland cement to control setting time
- Decorative mouldings and false ceilings
Its ability to undergo reversible hydration makes it extremely useful in building materials.
3. How is Plaster of Paris prepared from gypsum?
Plaster of Paris is prepared by heating gypsum at about 373–393 K to partially remove water of crystallisation.
CaSO4·2H2O(s) → CaSO4·½H2O(s) + 1½H2O(g)
- Gypsum is heated carefully.
- 1.5 molecules of water are removed.
- It forms calcium sulphate hemihydrate (Plaster of Paris).
This reaction is an example of a dehydration process.
4. Why is gypsum added to cement?
Gypsum is added to cement to control and slow down the setting time of cement.
- It prevents rapid reaction of tricalcium aluminate (C3A) with water.
- Reduces the risk of flash setting.
- Allows proper mixing, pouring, and finishing.
Without gypsum, cement would harden too quickly, making it difficult to use in construction.
5. How is gypsum used in agriculture?
Gypsum is used in agriculture as a soil conditioner and a source of calcium and sulphur nutrients.
- Supplies Ca2+ for plant growth.
- Provides sulphur in the form of SO42-.
- Improves structure of saline and sodic soils.
- Reduces soil compaction and increases water infiltration.
It does not significantly change soil pH, making it different from lime.
6. What is the role of gypsum in making moulds and casts?
Gypsum is used to make moulds and casts because it forms a hard mass when mixed with water.
CaSO4·½H2O(s) + 1½H2O(l) → CaSO4·2H2O(s)
- Plaster of Paris reacts with water.
- It re-forms gypsum.
- Heat is released (exothermic reaction).
This property is used in making statues, toys, surgical casts, and decorative materials.
7. How is gypsum used in the manufacture of drywall?
Gypsum is used as the core material in drywall panels because it is lightweight, fire-resistant, and easy to shape.
- Gypsum slurry is placed between two sheets of paper.
- It sets and hardens into solid boards.
- The water in CaSO4·2H2O provides fire resistance by releasing steam when heated.
This makes gypsum boards widely used in modern building construction.
8. What are the industrial uses of gypsum in chemistry?
In chemistry and industry, gypsum is used in cement production, ammonium sulphate manufacture, and as a drying agent.
- Added to Portland cement as a retarder.
- Used in producing (NH4)2SO4 fertilizer.
- Serves as a source of calcium salts.
Its chemical stability and sulphate content make it valuable in several industrial chemical processes.
9. What is the difference between gypsum and Plaster of Paris?
The main difference is that gypsum is CaSO4·2H2O while Plaster of Paris is CaSO4·½H2O.
- Gypsum: Fully hydrated calcium sulphate.
- Plaster of Paris: Partially dehydrated form.
- Gypsum is soft and crystalline.
- Plaster of Paris reacts with water and sets into hard gypsum.
Thus, Plaster of Paris is chemically derived from gypsum by controlled heating.
10. Why is gypsum considered fire-resistant?
Gypsum is considered fire-resistant because it contains water of crystallisation that absorbs heat during decomposition.
- Formula: CaSO4·2H2O
- On heating, it releases water vapour.
- This process absorbs heat and slows temperature rise.
The release of water during heating provides a protective barrier, which is why gypsum boards are widely used for fireproofing in buildings.
