Strontium was discovered by Adair Crawford, an Irish chemist, in 1790 while studying the mineral witherite (BaCO
3
). When he mixed witherite with hydrochloric acid (HCl) he did not get the results he expected. He assumed that his sample of witherite was contaminated with an unknown mineral, a mineral he named strontianite (SrCO
3
). Strontium was first isolated by Sir Humphry Davy, an English chemist, in 1808 through the electrolysis of a mixture of strontium chloride (SrCl
2
) and mercuric oxide (HgO). Today, strontium is obtained from two of its most common ores, celestite (SrSO
4
) and strontianite (SrCO
3
), by treating them with hydrochloric acid, forming strontium chloride. The strontium chloride, usually mixed with potassium chloride (KCl), is then melted and electrolyzed, forming strontium and
chlorine
gas (Cl
2
).
Most of the strontium produced today is used in the manufacture of color television picture tubes. It is also used to refine
zinc
and is combined with
iron
to make magnets.
Two strontium compounds, strontium carbonate (SrCO
3
) and strontium nitrate (Sr(NO
3
)
2
), burn with a bright, red flame and are used in fireworks and signal flares. Strontium carbonate is also used to make certain kinds of glass and is the base material for making most other strontium compounds.
Strontium-90, a radioactive
isotope
of strontium, is a common product of nuclear explosions. It has a
half-life
of about 28.8 years and decays into
yttrium
-90 through
beta decay
. Strontium-90 is especially deadly since it has a relatively long half-life, is strongly radioactive and is absorbed by the body, where it accumulates in the skeletal system. The radiation affects the production of new blood cells, which eventually leads to death.