Strontium

Occurrence

Strontium commonly occurs in nature, averaging 0.034% of all igneous rock and is found chiefly as the form of the sulfate mineral celestite (SrSO4) and the carbonate strontianite (SrCO3). Of the two, celestite occurs much more frequently in sedimentary deposits of sufficient size to make development of mining facilities attractive. Strontianite would be the more useful of the two common minerals because strontium is used most often in the carbonate form, but few deposits have been discovered that are suitable for development. The metal can be prepared by electrolysis of melted strontium chloride mixed with potassium chloride:

Related Topics:
Sulfate - Celestite - S - O - Carbonate - Strontianite - C - Metal - Electrolysis - Strontium chloride - Potassium chloride

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Sr2+ + 2 e- → Sr

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2 Cl- → Cl2 (g) + 2 e-

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Alternatively it is made by reducing strontium oxide with aluminium in a vacuum at a temperature at which strontium distills off. Three allotropes of the metal exist, with transition points at 235 and 540 °C. Strontium metal (98% pure) in January 1990 cost about $5/oz. The largest commercially exploited deposits are found in England.

Related Topics:
Oxide - Aluminium - Vacuum - Distills - Allotropes - Transition point - 1990 - England

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