Potassium nitrate is a colorless, crystalline potassium salt of nitric acid. The molecular formula KNO3 represents potassium nitrate. Synonyms for this compound salt include saltpeter, vicknite and potassium salt. Potassium nitrate was historically harvested from cave wall deposits of accumulated bat guano. A generally safe salt, it does show some toxicity at moderate doses, and it irritates the nose and throat. Potassium nitrate does not represent a toxic threat to the environment. While not explosive by itself, potassium nitrate can react violently with certain agents. For centuries, it comprised a top ingredient for gunpowder and fireworks. Modern uses for potassium nitrate include numerous products for households, agriculture and industry.
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Potassium nitrate is a crystalline potassium salt of nitric acid. Many products use potassium nitrate in homes, agriculture and industry. Some examples include toothpaste, fertilizers, fireworks, pesticides and molten salt for solar power plants.
In the modern home, potassium nitrate is used as an ingredient in common, everyday products. Both sensitivity toothpaste and tooth whitening products contain potassium nitrate. The salt can also be found in makeup primer. Various fertilizers, potting mixes and plant foods used in landscaping feature potassium nitrate, and stump removers also contain the salt. Some gas cartridge fumigant pesticides contain potassium nitrate.
A number of agricultural products use potassium nitrate as a component. Pyrotechnic fumigants to control rodents, insects and other pests contain potassium nitrate. These cartridges produce pest-killing gases in burrows to control wasps, skunks, coyotes and other animals that affect farms and crops. Due to its occurrence in nature, potassium nitrate typically does not cause negative environmental effects. Its chief risk as a burrow fumigant would be to animals such as burrowing owls that might inhabit the same burrows as pests. Potassium nitrate can also be found in many fertilizers used in agriculture.
Various industries rely upon potassium nitrate as an ingredient or otherwise helpful substance. Its use as a food preservative dates to the Middle Ages. Fireworks, gunpowder, matches and blasting powders represent incendiary products containing this salt. Rocket fuel may also contain potassium nitrate. The salt proves useful in tempering steel and manufacturing glass. Potassium nitrate also features in dental research, and the chemical industry relies upon potassium nitrate for temperature maintenance around reactors, as well as for making other chemicals. Potassium nitrate also serves the renewable energy sector as a major ingredient in “Solar Salt,” a molten salt used as heat storage in solar power plants. Stored heat is further used to generate steam for electricity production. This molten salt mixture provides sensible heat storage due to its high thermal stability, low cost and low vapor pressure.
- U.S. Department of Health & Human Services Household Products Database: Potassium Nitrate
- United States Environmental Protection Agency: R.E.D. FACTS Inorganic Nitrate/Nitrite (Sodium and Potassium Nitrates)
- International Letters of Chemistry, Physics and Astronomy: Environmentally and Economically Feasibility Manufacturing Process of Potassium Nitrate for Small Scale Industries: A Review
- Beilstein Journal of Nanotechnology: Thermal Energy Storage – Overview and Specific Insight Into Nitrate Salts for Sensible and Latent Heat Storage
- New Jersey Department of Health and Senior Services Hazardous Substance Fact Sheet: Potassium Nitrate
- Environmental Working Group Skin Deep Cosmetics Database: Potassium Nitrate
- Environmental Working Group Skin Deep Cosmetics Database: Potassium Nitrate – Products Containing the Ingredient
About the Author
J. Dianne Dotson is a science writer with a degree in zoology/ecology and evolutionary biology. She spent nine years working in laboratory and clinical research. A lifelong writer, Dianne is also a content manager and science fiction and fantasy novelist. Dianne features science as well as writing topics on her website, jdiannedotson.com.