Potassium nitrate is a naturally occurring mineral source of nitrogen. It is a nitrate with chemical formula KNO3. Its common names include saltpetre (American English saltpeter), Chilean saltpetre, and nitre. The name "saltpeter" is also applied to sodium nitrate. It is slightly soluble in cold water and very soluble in hot water. When it decomposes (on heating) it releases oxygen. Potassium nitrate is prepared commercially by the reaction of potassium chloride with sodium nitrate. It has been used extensively in the manufacture of gunpowder since about the 12th cent.; it is also used in explosives, fireworks, matches, and fertilizers, and as a preservative in foods (especially meats). It is sometimes used in medicine as a diuretic.
Potassium nitrate is used in the manufacturing of TV and computer screens as an oxidizer and firing agent. Black powder containing potassium nitrate is used as the fuel that launches pyrotechnics skyward. Because of its oxidizing and fluxing properties, potassium nitrate are used in the production of frits, which are applied as glazes on ceramic and metal bodies Because of its low melting point and high thermal conductivity, potassium nitrate are used in salt baths for metal
treatments and in formulations of heat transfer fluids.
Potassium nitrate (44% K2O), also known as nitrate of potash, is being used primarily on high value crops such as celery, tomatoes, potatoes, leafy vegetables and a few fruit crops. Potassium nitrate has application as a potassium source for crops which are highly sensitive to chloride, such as tobacco. It is an oxidising agent and should be handled and stored with care. It has a low salt index and provides nitrate N which may be desirable for these specialty crops. Production costs have limited general use for most agronomic field crops. Its nutrient composition is approximately: Potassium: 38%, Nitrogen: 13%