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Molten salt is salt which is solid at standard temperature and pressure (STP) but enters the liquid phase due to elevated temperature. A salt that is normally liquid even at STP is usually called a room temperature ionic liquid, although technically molten salts are a class of ionic liquids. ==Uses== Molten salts have a variety of uses. Molten chloride salt mixtures are commonly used as baths for various alloy heat treatments, such as annealing and martempering of steel. Cyanide and chloride salt mixtures are used for surface modification of alloys such as carburizing and nitrocarburizing of steel. Cryolite (a fluoride salt) is used as a solvent for aluminium oxide in the production of aluminium in the Hall-Héroult process. Fluoride, chloride, and hydroxide salts can be used as solvents in pyroprocessing of nuclear fuel. Molten salts (fluoride, chloride, and nitrate) can also be used as heat transfer fluids as well as for thermal storage. This thermal storage is used in solar thermal power plants.〔 (【引用サイトリンク】 publisher=National Renewable Energy Laboratory (NREL) ) 〕 A commonly used thermal salt is the eutectic mixture of 60% sodium nitrate and 40% potassium nitrate, which can be used as liquid between 260-550°C. It has a heat of fusion of 161 J/g,〔"(Molten salts properties )"〕 and a heat capacity of 1.53 J/(g K).〔 Experimental salts using Lithium may have a melting point of 116°C while still having a heat capacity of 1.54 J/(g K).〔Reddy, Ramana G. "(Novel Molten Salts Thermal Energy Storage for Concentrating Solar Power Generation )" page 9 ''University of Alabama College of Engineering''. Accessed: 9 December 2014.〕 Salts may cost $1,000 per ton, and a typical plant may use 30,000 tons of salt.〔Bullis, Kevin. "(Cheap Solar Power at Night )" ''MIT Technology Review'', 12 March 2012. Accessed: 9 December 2014.〕 Regular table salt has a melting point of 800°C and a Heat of fusion of 0.52 kJ/g.〔"(NaCl CID 5234, 4.2.14 Other Experimental Properties )" 〕〔"(NaCl Other Chemical/Physical Properties )" 〕 It is not used in solar power stations. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Molten salt」の詳細全文を読む スポンサード リンク
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