What are practical uses of calcium?

Answer 1

One must be careful to distinguish between the pure metallic element called Calcium and the compound Calcium carbonate that has often been colloquially referred to as simply calcium.

• Pure calcium is a soft grey alkaline earth metal,
• In compounds it is the fifth most abundant element by mass in the Earth's crust.

Calcium is essential for living organisms, particularly in cell physiology, where movement of the calcium ion Ca2+ into and out of the cytoplasm functions as a signal for many cellular processes. As a major material used in mineralization of bones and shells, calcium is the most abundant ion by mass in many animals.

Metallic calcium (the less common form in nature) is used in various commercial roles other than as nutritional supplements to support biological life. Some uses include:

• Working as a reducing agent in the extraction of other metals, such as uranium, zirconium, and thorium
• Working as a deoxidizer, desulfurizer, or decarbonizer for various ferrous and nonferrous alloys
• Working as an alloying agent used in the production of aluminium, beryllium, copper, lead, and magnesium alloys

The more 'natural form' of calcium is ionically bound in 'calcium containing compounds', it serves important roles in life as well:

• Calcium, combined with phosphate to form hydroxylapatite, is the mineral portion of human and animal bones and teeth.
• Used in the making of cements and mortars to be used in construction.
  Calcium hydroxide (slaked lime) is used in many chemical refinery processes and is made by heating limestone at high temperature (above 825°C) and then carefully adding water to it. When lime is mixed with sand, it hardens into a mortar and is turned into plaster by carbon dioxide uptake. Mixed with other compounds, lime forms an important part of Portland cement.
• Calcium carbonate (CaCO3) is one of the common compounds of calcium. It is heated to form quicklime (CaO), which is then added to water. This forms another material known as slaked lime (Ca(OH)2), which is an inexpensive base material used throughout the chemical industry. Chalk, marble, and limestone are all forms of calcium carbonate.
• Various calcium salts are used as an alternative to sodium chloride as road salt.
  
• Used in the making of cheese, where calcium ions influence the activity of rennin in bringing about the coagulation of milk

Answer 2

Bones and shells in life forms, used in cement and plaster of paris.

Answer 3

one use of calcium is that we drink it in water

Answer 4

It is used in cement industry. Also used in medical industry to make plaster of Paris. Mainly used in the construction industry.

Answer 5

it can reduce the risk of cancer