Niter, deposits

The Chilean niter deposits contain up to 0.3% iodine in the form of calcium iodate. After dissolution and recrystallization of the niter, the supernatant liquor contains up to 9 g/L of sodium iodate. Iodine is liberated by reduction with sulfur dioxide (in the form of sodium bisulfite), further reduction to iodide being avoided by maintaining stoichiometry ... 

Niter deposits [including KNO3, Chilean saltpeter, NaN03, and wall saltpeter, Ca(N03)2] represent localized reservoirs of terrestrial nitrogen. Their entry into the biogeochemical cycle is catalysed by Man, but a role for organisms in their formation, while possible (Breger, 1911), has yet to be proven. 

Chilean niter deposits are mosdy sodium nitrate, but they also contain 0.3% iodine in the form of calcium iodate, Ca(I03)2. After the sodium nitrate in the niter is dissolved and recrystallized, the remaining solution contains 9 g/L sodium iodate, NaI03(aq). The NaI03 is converted to iodine when it reacts with sulfur dioxide and water. 

Na nitrate occurs native in large deposits in the rainless districts of Chile, hence it is often called Chile saltpeter or Chile niter . The Na nitrate in the deposits constitutes from 20 to 50% in a distinct stratum of earth known as caliche . The caliche is crushed and lixiviated in large tanks of w heated by steam. The settled soln is run off to crystallizers, where crude nitrate separates, the mother liquors being run back to the lixiviators. The crysts are washed with a little w and dried in the sun they contain 95—96% Na nitrate (Ref 1)... 

Soda niter or sodium nitrate (NaNO ) is the most abundant of the nitrate minerals. It is used for fertilizer, explosives, and preservatives. The natural deposits are located in northern Chile, which was the original source for many years. More recently, nitrogen fixation, which extracts nitrogen from air, has been used for producing sodium nitrate. This synthetic process has greatly increased the availability of this useful sodium salt by ehminating the need for the natural source. It is used to preserve and cure meats and is used in photography, in pharmaceuticals, and as a color fixative in fabrics. 

The potassium nitrate used in gunpowder was originally obtained from natural mineral deposits of niter. Small quantities formed as efflorescence deposits on damp stone walls were... 

Some of the Atacama nitrate deposits are relatively pure sodium nitrate (nitratite or soda niter). This is the case with some near-surface veins in bedrock (Ericksen and Mrose, 1972) and with some caliche bianco. However, most of the deposits are impure and contain substantial amounts of other salts, including a range of sulphates, chlorides, nitrates, borates, iodates, perchlorate and chromates. Ericksen (1981), Pueyo et al. (1998) and Searl and Rankin (1993), provide a detailed list of such minerals (Table 12.1), although some of Searl and Rankin s identifications have been challenged by Ericksen (1994). One of the nitrate minerals, humberstonite, derives its name from Humberstone, one of the nitrate towns in the area (Mrose et al., 1970). Of the impurities, sodium chloride (halite) appears to be the most important and may often exceed the percentage of nitrate (see e.g., Penrose, 1910, p. 14). A detailed chemical analysis of the Maria Elena nitrate deposits is provided by Collao et al. (2002). They report (p. 181) ... 

Ericksen, G.E. Mrose, M.E. (1972) High purity veins of soda-niter, NaN03, and associated saline minerals in the Chilean nitrate deposits. U.S. Geological Survey Professional Paper 800-B, B43-B49. 

In 1898, the world was rather rudely awakened by a statement by Sir William Crookes, an eminent authority, to the effect that the world was facing ultimate starvatian because of its dependence upon the natural niter beds of Clnle for Its nitrogen supply. While later investigations have given assurance that the exhaustion of these deposits would... 

Sodium is the most abundant of the alkali metals and is the sixth most abundant element in the Earth s crust, with an abundance of roughly 2.36 wt.%. Owing to its high chemical reactivity with water and, to a lesser extent, with air, sodium metal never occurs free in nature however, the element is ubiquitous and occurs naturally in a wide range of compounds. Sodium chloride is the most common compound of sodium and is dissolved either in seawater or in the crystalline form of halite or rock salt [NaCl, cubic]. However, it is widely present in numerous complex silicates such as feldspars and micas and other nonsilicate minerals such as cryolite [NajAlF, monoclinic], natronite or soda ash [Na COj, mono-clonic], borax [Na B O,. lOH O, monoclinic], sodium hydroxide or caustic soda [NaOH], Chilean saltpeter, and nitratite or soda niter [NaNOj, rhombohedral]. Obviously, the chief ore is the sodium chloride recovered from either brines or rock salt ore deposits. There are... 

In the 18 century the word niter was used and caused confusion. Was it soda or saltpeter Etienne-Frangois Geoffrey in Paris made a distinction, saying that soda is niter or natron of the ancients (sodium carbonate) while modem niter is saltpeter (potassium nitrate). He and others had observed how saltpeter is formed in the earth below bams by reaction between plants and stale urine. Soda on the other hand could not be manufactured, but was extracted from natural deposits in the earth and from natron lakes, for instance in Egypt. 

Saltpeter (Niter) (Potassium nitrate) Pyrotechnics Explosives Matches Medicine Natural deposits Drug store... 

---