Calcium Sulphate: A Versatile and Widely Used Industrial Mineral

Introduction
Calcium sulphate, also known as gypsum, is a widely occurring mineral found in nature. It is an evaporite mineral with the chemical formula CaSO4.2H2O. Calcium sulphate has a wide range of applications across many industries due to its properties. In this article, we will explore the various uses of calcium sulphate in different sectors of the economy.

Occurrence and Properties
Calcium sulphate occurs naturally in mineral deposits formed by the evaporation of saline lakes and seas. Major deposits of calcium sulphate are found in the United States, Canada, Ukraine, France and Spain.
Calcium sulphate has several properties that make it commercially valuable. It has a high hardness and low solubility in water. When heated, it releases its crystal water molecules leaving a porous powder. Calcium sulphate is non-toxic, non-flammable and poses low risks to health and environment during production and use. These properties open up multiple applications for calcium sulphate.

Construction Industry
By far the largest use of calcium sulphate is in the construction industry as a building material. Calcium sulphate in its hemihydrate form (CaSO4.1/2H2O) is used to produce wallboard, also known as drywall or plasterboard. Around 90% of the gypsum produced globally is used to manufacture wallboard. Other construction uses include cement, stucco, moldings and castings due to calcium sulphate's fire resistance and sound insulation properties.

Agriculture
Calcium Sulphate has important applications in agriculture due to its capability to amend soil properties. As a soil conditioner, calcium sulphate increases the uptake of nutrients by plants and controls soil acidity. Farmers apply calcium sulphate fertilizers to increase crop yields. It is also used to condition hydroponic soil-less media and remedy deficiencies of calcium and sulphur in crops.

Industrial Applications
Beyond construction and agriculture, calcium sulphate has diverse industrial applications utilizing its chemical and physical properties:

Plaster Industry
Calcium sulphate plaster is used as a decorative interior finish on walls and ceilings. The hydrous form sets as a solid that can be molded, carved or finished in various artistic styles.

Food Industry
In the food industry, calcium sulphate is approved as a processing aid and additive. It acts as a firming agent, neutralizer or inhibitor in products like baked goods, fruits, vegetables and meat.

Pharmaceuticals
Calcium sulphate is used as a binding agent in tablet manufacturing and as a diluent in medicinal preparations and supplements that supply calcium and sulphur to the body.

Other Uses
Other minor uses of calcium sulphate include as a hardening retarder in Portland cement, glaecohemaite production, water treatment, ceramics manufacturing, metallurgy and electronics due to its thermal resistance.

Environmental and Health Impacts
While calcium sulphate poses low toxic risks, its mining and production processes can impact the environment if not carried out sustainably:

- Open pit mining damages land and causes pollution if not properly reclaimed.
- Air pollution occurs from dust during quarrying, manufacturing and transport.
- Water pollution risks exist if contaminated water is discharged without treatment.

However, with implementation of environmental management standards, these impacts can be minimized. Occupational exposure to calcium sulphate dust needs control through ventilation and dust suppression methods in workplaces.

Conclusion
In summary, calcium sulphate is a versatile mineral with extensive commercial applications owing to its hardness, chemical inertness and hydration properties. The construction industry remains its largest end-use market for manufacturing building materials like wallboard and plaster. Other sectors like agriculture, food production, medicine and more also continually harness calcium sulphate's useful traits. With judicious mining and production practices, this important industrial mineral can be sourced sustainably on a large scale to support global economic development.

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