Lithium is the chemical element with atomic number 3, symbol Li. It is an
alkali metal, located in the first group of the periodic table of the elements.
The nuclei of the two stable isotopes of lithium (6Li and 7Li) are among the
atomic nuclei with the lowest binding energy per nucleon of all stable isotopes,
which means that these nuclei are actually quite unstable compared to those
other light elements. That is why they can be used in nuclear fission reactions
as well as nuclear fusion. This is also the reason why lithium is less abundant
in the solar system than 25 of the 32 lightest chemical elements11. Its relative
overabundance in nature compared to predictions of only primordial and stellar
nucleosyntheses is in fact explained by its interstellar nucleosynthesis
(phenomenon of cosmic spallation) by bombardment of heavier elements by cosmic
rays.
Lithium plays an important role in nuclear physics. Lithium is used for the
production of tritium by the reaction: 6Li + n → 4He + 3H. Furthermore, the
lithium deuteride of formula 6Li2H is used as fuel for the H-bomb.
Pure lithium is a soft metal, silver gray in color, which tarnishes and oxidizes
very quickly on contact with air and water, taking on a dark gray hue quickly
turning to anthracite and black. It is the lightest solid element. Like other
alkali metals, metallic lithium reacts easily with air and with water. It is for
this reason preserved in mineral oil to preserve it from the air.
Lithium is used to produce rechargeable or high-voltage cells and batteries
(65%), by the glass and ceramics industry (18%), special lubricants, the
treatment of stale air by CO2, by metallurgy and the rubber and thermoplastics
industry, fine chemicals, alloy production.
Very reactive, lithium does not exist in the native state in the natural
environment, but only in the form of ionic compounds. It is extracted from
pegmatite type rocks, as well as clays and brines. The chemical element is most
often used directly from mining concentrates. To obtain it industrially in the
metallic state, the technique of electrolysis in molten salt (55% LiCl and 45%
KCl, at 400 ° C.) is used.
World lithium reserves were estimated by the USGS at 13 million tonnes at the
end of 2010, of which 58% in Bolivia and 27% in China. By February 2020, this
estimate from the USGS had increased to 17 million tonnes, and the total
resources identified to 80 million tonnes, including 26% in Bolivia, 21% in
Argentina, 11% in Chile, 8% in Australia and 6% in China. World production,
meanwhile, amounted to 77,000 tonnes in 2019, excluding the United States (whose
data is not made public by the USGS), mainly provided by Australia (55%), the
Chile (23%), China (10%) and Argentina (8%).
Lithium only exists, in concentrations allowing profitable economic
exploitation, in very few places on Earth. It is mainly an impurity of the salts
of other alkali metals, mainly in the form of:
chlorides (LiCl), mainly in the brines of certain old continental salt lakes and
mixed with other alkali metal salts, certain geothermal waters or oil fields;
silicates, including spodumene, LiAl (Si2O6) or petalite (Li (AlSi4O10)) in
pegmatite;
hectorite, a kind of clay with the formula NaO, 4Mg2,7LiO, 3Si4O10 (OH) 2,
resulting from the alteration of certain volcanic rocks;
jadarite, Li Na Si B3O7 (OH) which is a borate.
rhassoul, a Moroccan clay rich in stevensite (Mg3Si4O10 (OH) 2 and lithium).
The largest deposit in the world is the salar de Uyuni, in the department of
Potosí, in the southwest of Bolivia. With a third of the world's resources, it
is of particular interest to the Bolloré group. In March 2008, Bolivia
authorized the exploitation of lithium in the fossil salt desert of Uyuni and
the creation of an extraction plant
The second largest deposit is the salar de Atacama, in Chile, which has been the
world's leading exporter since 1997, with the German company Chemetall as the
main operator.
Argentina also has a lithium deposit, with the Salar del Hombre Muerto, about a
hundred kilometers north of Antofagasta de la Sierra, in the north-west of the
country, difficult to access (only natural dirt tracks lead to it) but operated
by FMC since 1995.
In Western Australia, in the pegmatite of the Greenbushes mines, Talison Lithium
Ltd extracted around 2010-2011 more than 300,000 t / year of spodumene
concentrate containing 8,000 to 9,000 t of Li (more than 25% of world production
of lithium (proven and probable reserves: 31.4 million t of ore containing 1.43%
of Li)) 52. In the same region Galaxy Resources began in 2010 the open-cast
exploitation of a pegmatite deposit Mine of Mount Cattlin, near Ravensthorpe
aiming at a production of 137,000 t / year of spodumene concentrate at 6% Li2O
with coproduction tantalum oxide. In 2012, 54,047 t of spodumene concentrate was
produced. Proven and probable reserves are 10.7 million t of ore containing
1.04% Li2O and 146 ppm of Ta2O5 "mainly shipped to China and transformed into
lithium carbonate).
Other deposits are exploited, notably dry lakes in Tibet54, in Russia and in the
United States (Silver Peak, Nevada, exploited by Rockwood Lithium) or in
Zimbabwe (Bikita mine, open pit, with 30,000 t / year of ore at 4.45% Li2O).
Satellite images of the Salar del Hombre Muerto in Argentina (left) and of Uyuni
in Bolivia (right). Salt deserts are rich in lithium. The lithium is extracted
by concentration of the brine after pumping and evaporation in salt marshes
(visible on the image on the left).
The geothermal waters of Salton Sea (California) are as rich in lithium as the
Bolivian and Chilean salt lakes. Their extraction had been envisaged, but the
company in charge of the project closed its doors in 2015.
In Canada, a deposit was discovered in 2010 near James Bay, exploited by several
companies, until its closure in 2014. A mine project is being studied in the
Abitibi.
In Afghanistan, very important reservations were mentioned in June 2010 in the
press.
rhenium germanium zirconium cadmium hafnium
barium lithium beryllium strontium calcium
Tantalum gadolinium samarium yttrium ytterbium
Lutetium praseodymium holmium erbium thulium dysprosium
terbium europium lanthanum cerium neodymium scandium