Calcium nitrate is a compound of nitrogen and calcium. It is mainly produced in a granulated form and used as nitrogen fertilizer in agriculture, and it is used in waste-water treatment. It can also be used to accelerate concrete admixtures, regenerate cold packs and transfer heat.
Calcium nitrate is a colorless anhydrous salt obtained by treating limestone with weak nitric acid. It also forms during the absorption of nitrogen oxide by milk of lime.
Like other, related alkaline-earth-metal nitrates, calcium nitrate decomposes upon heating to release nitrogen dioxide. The compound dissolves quickly in water and can be absorbed rapidly by plants in all soils and climates, according to Azot-Trans. The nitrogen in calcium nitrate also helps a plant absorb other nutrients in the soil, while the calcium provides the necessary nutrition to promote cell growth in a plant.
Calcium nitrate is also used to prevent odors in waste water by creating an anoxic biology, which stops the metabolism of odor-producing sulfates.
The calcium ion in calcium nitrate accelerates the formation of calcium hydroxide, which helps increase the rate at which concrete settles. Furthermore, the nitrate ion leads to the formation of iron hydroxide, whose protective layer reduces corrosion of the concrete reinforcement, according to Wikipedia.