Trona

Trona (trisodium hydrogendicarbonate dihydrate also sodium sesquicarbonate dihydrate); 3()(HCO3)•2 is a non-marine evaporite mineral.Mineral galleries, 2008 It is mined as the primary source of sodium carbonate in the United States, where it has replaced the Solvay process used in most of the rest of the world for sodium carbonate production.
== Etymology ==
The word "trona" comes to English by way of either Swedish () or Spanish (), with both possible sources having the same meaning as in English. Both of these derive from the Arabic trōn which in turn derives from the Arabic natron, and Hebrew (natruna), which comes from ancient Greek (nitron), derived ultimately from ancient Egyptian ntry (or nitry).
== Natural deposits ==
 Trona is found at Owens Lake and Searles Lake, California; the Green River Formation of Wyoming and Utah; the Makgadikgadi Pans in Botswana and in the Nile Valley in Egypt.C. Michael Hogan (2008) Makgadikgadi, The Megalithic Portal, ed. A. Burnham The trona near Green River, Wyoming is the largest known deposit in the world and lies in layered evaporite deposits from below ground, where the trona was deposited in a lake during the Paleogene Period.Banks, Chad (2007-05-24). What is Trona? Wyoming Mining Association. Retrieved on 2009-07-01. Trona has also been mined at Lake Magadi in the Kenyan Rift Valley for nearly 100 years. The northern part of Lake Natron is covered by a 1.5 m thick trona bed,Manega, P.C., Bieda, S., 1987. Modern sediments of Lake Natron, Tanzania. Sciences Geologiques. Bulletin 40, 83–95. and occurs in 'salt' pans in the Etosha National Park in Namibia.Eckardt, F. D., Drake, N., Goudie, A. S., White, K., & Viles, H. (2001). The role of playas in pedogenic gypsum crust formation in the Central Namib Desert: a theoretical model. Earth Surface Processes and Landforms, 26(11), 1177-1193. The Beypazari region in the Ankara Province of Turkey has some 33 trona beds in two fault-bound lensoid bodies in and above oil shales of the Lower Hirka Formation (16 in the lower and 17 in the upper body).Helvaci, C., 1998. The Beypazari trona deposit, Ankara Province, Turkey. In: Dyni, J.R., Jones, R. W. (Eds.), Proceedings of the first international soda-ash conference; Volume II, v. 40: Laramie,WY, Public Information Circular - Geological Survey of Wyoming, pp. 67–103. The Wucheng basin trona mine, Henan Province China has some 36 trona beds (693–974 m deep), the lower 15 beds are 0.5–1.5 m thick, thickest 2.38 m; the upper 21 beds are 1–3 m thick, with a maximum of 4.56 m hosted and underlain by dolomitic oil shales of the Wulidui Formation.Zhang, Youxun, 1985. Geology of the Wucheng trona deposit in Henan, China. In: Schreiber, B.C.,Warner, H.L. (Eds.), Sixth international symposium on salt, 1, pp. 67–73.
Trona has also been found in magmatic environments.Markl, G., and Baumgartner, L. (2002) pH changes in peralkaline late-magmatic fluids. Contributions to Mineralogy and Petrology, 144, 331-346. Markl and Baumgartner show that trona can be formed by autometasomatic reactions of late-magmatic fluids or melts (or supercritical fluid-melt mixtures), with earlier crystallized rocks within the same plutonic complex, or by large-scale vapor unmixing in the very final stages of magmatism.
== Crystal structure ==
The crystal structure of trona was first determined by Brown et al. (1949).Brown, C.J., Peiser, H.S., and Turner-Jones, A. (1949) The crystal structure of sodium sequicarbonate. Acta Crystallographica, 2, 167-174. The structure consists of units of 3 edge-sharing sodium polyhedra (a central octahedron flanked by septahedra), cross-linked by carbonate groups and hydrogen bonds. Bacon and Curry (1956)Bacon, G.E., and Curry, N.A. (1956) A neutron-diffraction study of sodium sesquicarbonate. Acta Crystallographica, 9, 82-85. refined the structure with two-dimensional single-crystal neutron diffraction, and suggested that the hydrogen atom in the symmetric (HC2O6)3− anion is disordered. The environment of the disordered H atom was later investigated by Choi and Mighell (1982)Choi C.S., and Mighell A.D., (1982) Neutron diffraction study of sodium sesquicarbonate dihydrate. Acta Crystallographica, B38, 2874-2876. at 300 K with three-dimensional single-crystal neutron diffraction: they concluded that the H atom is dynamically disordered between two equivalent sites, separated from one another by 0.211(9) Å. The dynamically disordered H atom was reinvestigated at low temperature by O'Bannon et al. 2014 O’Bannon, E., Beavers, C. M., & WIllIams, Q. (2014). Trona at extreme conditions: A pollutant-sequestering material at high pressures and low temperatures. American Mineralogist, 99(10), 1973-1984. and they concluded that it does not order at temperatures as low as 100K.
== Uses of trona ==
*Trona is a common source of soda ash which is a significant economic commodity because of its applications in manufacturing glass, chemicals, paper, detergents, and textiles.
*It is used to condition water.
*It is used to remove sulfur from both flue gases and lignite coals.Kong Y., and Wood M.D. (2010) Dry injection of trona for SO3 control. Power, 154, 114-118.Sutcu H., and Eker Y. (2013) The removal of sulfur from Dursunbey and Iskilip lignites in Turkey, using natural trona: 1. The effect of the thermal method. Energy Sources Part A-Recovery Utilization and Environmental Effects, 35, 83-91. 
*It is a product of carbon sequestration of flue gases.Yoo M., Han S.J., and Wee J.H. (2013) Carbon dioxide capture capacity of sodium hydroxide aqueous solution, Journal of Environmental Management, 114, 512-519. 
*It is also used as a food additive.Ekosse, G.I.E. (2010) X-ray diffraction study of kanwa used as active ingredient in achu soup in Cameroon. African Journal of Biotechnology, 9, 7928-7929.Nielsen, J.M. (1999) East African magadi (trona): Fluoride concentration and mineralogical concentration. Journal of African Earth Sciences, 29, 423-428.
== Mining operations ==
* Magadi Soda Company
* Searles Valley Minerals Inc.
* Solvay
* Tata Chemicals
* FMC Corporation
* General Chemical
* OCI Chemical Corp.
* American Natural Soda Ash Company
== See also ==
* Natron
* Nahcolite
* Shortite
* Sodium sesquicarbonate
* Thermonatrite
== References ==
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