Potassium nitrate with the chemical formula KNO3 is made from potassium chloride and a source of nitrate. Potassium nitrate is a strong oxidizer, noncombustible but accelerates the burning of combustible materials. Potassium nitrate is widely used as a fertilizer.
Potassium chloride commercially can be made by reaction of potassium chloride with nitric acid in the presence of oxygen at 100°C with the following reaction :
2 KCl + 2 HNO3 + 1/2 O2 → KNO3 + Cl2 + H2O
to produce potassium nitrate, water, and nitrosyl chloride. The nitrosyl chloride then is oxidized to chlorine and nitrogen dioxide with nitric acid.
Potassium nitrate is a major source of both nitrogen and potassium. They are 2 of the most important macronutrients required for soil being fertile and for plant growth. Commonly applied on vegetables and fruit crops. Potassium nitrate can increases the starch content, fruit yield, and size.
Recently, potassium nitrate has been used in some toothpaste for treating sensitive teeth.
Potassium nitrate is used for meat processing such as salami, dry-cured ham, and in the brine used to make corned beef. This compound is also used as a food additive as a preservative.
Potassium nitrate is the oxidizer in gunpowder for fireworks, revolvers, and cigarettes.