Editing Strontium (section)

==Production==
The major producers of strontium as celestine as of January 2024 are Spain (200,000&nbsp;[[metric ton|t]]), Iran (200,000&nbsp;t), China (80,000&nbsp;t), Mexico (35,000&nbsp;t); and Argentina (700&nbsp;t).<ref name="USGSMinRep24">{{Cite report |url=https://pubs.usgs.gov/publication/mcs2024 |title=Mineral commodity summaries 2024 |series=Mineral Commodity Summaries |date=January 2024 |doi=10.3133/mcs2024 |isbn=978-1-4113-4544-7 |publisher=U.S. Geological Survey |location=Reston, VA |language=en}}</ref> Although strontium deposits occur widely in the United States, they have not been mined since 1959.<ref name="USGSMinRep24" />

A large proportion of mined celestine (SrSO<sub>4</sub>) is converted to the carbonate by two processes. Either the celestine is directly leached with sodium carbonate solution or the celestine is roasted with coal to form the sulfide. The second stage produces a dark-coloured material containing mostly [[strontium sulfide]]. This so-called "black ash" is dissolved in water and filtered. Strontium carbonate is precipitated from the strontium sulfide solution by introduction of [[carbon dioxide]].<ref>{{cite book | url = https://books.google.com/books?id=5smDPzkw0wEC&pg=PA401 | title = Production of SrCO<sub>3</sub> by black ash process: Determination of reductive roasting parameters| page = 401 | isbn = 978-90-5410-829-0 | last1 = Kemal | first1 = Mevlüt | last2 = Arslan | first2 = V. | last3 = Akar | first3 = A. | last4 = Canbazoglu | first4 = M. | date = 1996| publisher = CRC Press}}</ref> The sulfate is [[Redox|reduced]] to the [[sulfide]] by the [[carbothermic reduction]]:

:SrSO<sub>4</sub> + 2 C  →  SrS + 2 CO<sub>2</sub>

About 300,000 tons are processed in this way annually.<ref name="Ullmann" />

The metal is produced commercially by reducing strontium [[oxide]] with [[aluminium]]. The strontium is [[distillation|distilled]] from the mixture.<ref name="Ullmann" /> Strontium metal can also be prepared on a small scale by [[electrolysis]] of a solution of [[strontium chloride]] in molten [[potassium chloride]]:<ref name="Greenwood111" />

:Sr<sup>2+</sup> + 2 {{SubatomicParticle|electron}} → Sr
:2 Cl<sup>−</sup> → Cl<sub>2</sub> + 2 {{SubatomicParticle|electron}}