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Downstairs
Published in Michael Allaby, Conservation at Home, 2019
Nitrate from excessive fertilizer use is sometimes present in certain foods, especially spinach. Saltpetre (potassium nitrate) or Chile saltpetre (sodium nitrate) are used as preservatives, especially for ‘cured’ meats such as ham and bacon. They are not added to proprietary baby foods (see clean water, page 38). Nitrate used in curing is reduced to nitrite, and nitrite is often used directly. It improves the colour and flavour of the meat and at the same time kills bacteria, most importantly Clostridium botulinum, which produces one of the most potent of all poisons and causes botulism. The nitrite also combines with amines which are naturally present in the meat to form nitrosamines. Very large doses of nitrosamines cause cancer in experimental animals; thus the use of nitrates and nitrites is strictly regulated even though they have not been proved to cause cancer in human beings. The incidence of stomach cancer, which nitrosamines might be expected to cause, has in fact been falling for some years.
Applied Chemistry and Physics
Published in Robert A. Burke, Applied Chemistry and Physics, 2020
Potassium nitrate (saltpeter) is a colorless or white crystalline powder or crystals. It is a dangerous fire and explosion risk when heated or shocked. It is a strong oxidizing agent. It is used in the manufacture of pyrotechnics, explosives and matches. It is often used in the illegal manufacture of homemade pyrotechnics and explosives.
The Chemical Industry: An Overview
Published in Richard J. Sundberg, The Chemical Century, 2017
A few fundamental chemical processes were done for commerce in the 18th century. Sulfuric acid (H2SO4) was made by heating sulfur with KNO3 in leadlined containers, a process developed in England by John Roebuck about 1750. Soap was made by reaction of animal fats with the carbonate minerals natron and trona (hydrated forms of Na2CO3). Potassium nitrate (KNO3, saltpeter) was collected from stables and purified for use in the manufacture of black powder (see Section 1.1). Sodium carbonate (Na2CO3, also called soda) was needed by the glass and soap industries. In 1775, the French Academy of Science offered a prize for the production of pure soda. Nicolas LeBlanc, a physician, found that it could be produced from salt by heating with chalk (CaCO3), coal, and H2SO4. A plant was established and the process was patented in 1791. The plant was confiscated during the French Revolution. LeBlanc spent the rest of his life unsuccessfully seeking restitution and in 1806, he shot himself. LeBlanc ProcessNaCl+CaCO3+2C+H2SO4→Na2CO3+2HCl+CaS=2CO2Bleaching Powder ProcessHCl+MnO2→Cl22Cl2+2CaO→Ca(OCl)2+CaCl2
Endangered Salares: micro-disasters in Northern Chile
Published in Tapuya: Latin American Science, Technology and Society, 2021
Cristóbal Bonelli, Cristina Dorador
In fact, the Cerro Dominador CSP plant is beginning operations in the middle of the Atacama Desert. It will be the largest such plant in Latin America, with a capacity of 110 KMW and 17.5 h of thermal storage. Its main tower is 220 meters tall, affording views throughout the desert. The salts it relies on to function are abundant in the Atacama: potassium nitrate and sodium chloride. The potassium salts come from the brines of Atacama Salar – an area that also attracts the world’s largest lithium companies – and the sodium nitrate salts (saltpeter) are derived from the plain’s caliche deposits using a process that involves water from the Salar de Llamara and the Pampa del Tamarugal aquifer.