Chemical Formula and Symbols
Potassium nitrate is known by its chemical symbol, KNO3, and goes by such names as collo-bo, saltpeter and niter. It is a natural source of nitrogen.
Physical Properties
Potassium nitrate's colorless crystals dissolve easily in water and remain stable unless mixed with other substances, when it can become explosive because of its strong oxidizing properties. Its melting point occurs at 334 degrees centigrade and it reaches boiling at 400 degrees centigrade. It produces orange flames in less-pure forms and lilac flames in purer forms. Hazardous signs must be displayed by trucks carrying this oxidizer.
Sources of Potassium Nitrate
Nitrates in general are manufactured from ammonia produced using the Haber process, which involves mixing nitrogen from the air (which is about 78 percent nitrogen) and hydrogen from natural gas. The catalyst for the reaction is iron with some potassium hydroxide added. Then an ammonia solution is combined with some form of potassium chloride.
Before industrial production of nitrogen, potassium nitrate was found in crystal deposits or as a byproduct of the decomposition of organic materials, especially those in manure piles.
Potassium Nitrate Uses
Common applications for potassium nitrate include black powder used in gun ammunition and rocket propellants, and fireworks. As a food preservative, potassium nitrate is converted to saltpeter and used in salted meats. Mixing concentrated sulfuric acid with a potassium nitrate solution, then distilling the mixture, produces nitric acid and potassium sulfate. Potassium nitrate makes an excellent fertilizer. Its status as an oxidizer makes it ideal as a cigarette additive, helping them to burn evenly. Because it promotes decomposition, potassium can also be used as a tree stump eradicator. Its solubility in water makes it an efficient temporary rust inhibitor.
Hazards and Solutions
Safety glasses and protective clothing are recommended when handling potassium nitrate.
Exposure to combustible substances can lead to fire. Contact with eyes, skin and the respiratory system causes irritation. Eyes should be flushed and skin washed with water. Potassium nitrate is harmful when swallowed and lethal when taken at doses equal to or greater than 1901 mg per kg-1 of body weight. If the person is still conscious, the mouth should be rinsed with water, then emergency services contacted.