Lithium has been a popular element lately. It is considered the lightest solid
element on earth. Li was discovered in 1817. One reasonably could assume that after
decades of brilliant achievement, lithium had lived its finest hour. But the assumption
is without merit. Lithium's boundaries today are wider than yesterday. Lithium's
potential today is greater than yesterday. The last ten years its application has
expanded especially in batteries, which are applied in laptops, cameras, cell phones
and all kind of electronic gadgets. Everyday is applied more and more rechargeable
tools, power back-up stations and motorbikes. In the coming years it will expand to
the hybrid and electrical vehicles.
The lithium hype is all caused because of its specific and unique characteristics of this
tiny but powerful element; it is lightest metal and has huge electrical chemical
potential resulting in very high energy densities.
Lithium (atomic number 3, atomic weight 6.941) is a silvery-white metal, slightly harder than sodium
but softer than lead. It is extremely light. Lithium appears in the periodic table as the first element in
Group I, the alkali metals group. Like the other metals in the group - sodium, potassium, rubidium
and cesium - it is so chemically active that, in nature, it never occurs as a pure element, but is always
bound in stable minerals or salts.
In some of its compounds, however, lithium shows a great resemblance to Group II, or alkaline earth metals. For example, the water solubility of lithium hydroxide is substantially lower than that of other alkali hydroxides. In general, lithium's physical and chemical properties stem from its atomic structure.
A single atom of lithium consists of a nucleus (three protons and either three or four neutrons) with
three electrons orbiting in two shells. The inner shell (the helium shell) contains two electrons and is chemically inert. The outer shell contains only one electron.
Lithium, more than any other alkali metal, tends to eject this electron from its outermost shell. The
resulting lithium-ion carries a positive charge (+1). In solid metal, individual lithium atoms are arranged geometrically in a cubic lattice and can transfer a negative charge from place to place. This electron movement makes lithium metal an excellent electrical conductor.
Lithium is derives its excellence from the following important characteristics:
-
Low density
-
Low Melting point
-
Soft and easy to form
-
Low dynamic viscosity
-
Very high ionization energy
-
Very high electrode potential
-
Very good electrical conductivity
-
Low resistivity
Very reactive, though considerably less so than other alkali metals. The presence of sodium as an
impurity, even in amounts of 0.5 – 1 %, increases its reactivity, e.g., for the formation of lithium alkyls
from lithium metal and organic halides.
A freshly cut surface of lithium metal has a silvery luster. At room temperature in dry air with a
relative humidity of less than 1 %, the surface remains shiny for several days, although a very thin
passive surface layer is formed that is hardly visible to the naked eye and consists mainly of lithium carbonate and oxygen-containing compounds. Lithium metal can therefore be processed in dry air. However, in moist air a dull gray coating, consisting mainly of lithium nitride, lithium oxide, and lithium hydroxide, forms within a few seconds. If lithium ingots are allowed to remain in contact with air for
some weeks, the reaction with atmospheric nitrogen extends into the interior of the metal with the formation of reddish brown lithium nitride and can lead to ignition. Even at room temperature dry nitrogen reacts slowly with lithium metal.
Protective gases for lithium metal include the noble gases, or pure sulfur hexafluoride up to 225 °C.
Mineral oil is also suitable as a protective medium.
Lithium reacts with water with formation of hydrogen, which ignites under normal conditions only
if the metal is finely divided. Molten lithium reacts explosively with water.
Lithium reacts with hydrogen to form lithium hydride. This reaction is carried out on an industrial scale
at 600 – 1000 °C. Lithium reacts with gaseous ammonia at elevated temperature to form lithium
amide. The vigorous reaction with halogens produces incandescence. Organic compounds containing
active hydrogen or halogen usually react with lithium to form the corresponding organolithium
derivative.
Lithium History
Lithium, the third element in the periodic table of elements, was discovered in 1817 by a Swedish
scientist named Arfwedson. He had analyzed the content of a mineral called spodumene; the results
of the analysis left a sizable percentage of the ore's make-up unaccounted for. Further work resulted
in the extraction of a compound with chemical properties suggesting an unknown element was
present. Since the new element had been found in chunks of spodumene ore, Arfwedson called it
"lithium," from the Greek word for stone.
It was not until 1855 that lithium was prepared as a free metal. In those early years, lithium was little
more than a laboratory curiosity. Lithium-bearing minerals were sometimes used as exotic additives to ceramic compositions. Not until World War II were the special properties of lithium compounds fully investigated and exploited. A compact, lightweight source of hydrogen was needed for use in
emergency signaling balloons. Lithium hydride was found to be ideal for this purpose; one pound
of lithium hydride reacts with seawater to generate 45 cubic feet of hydrogen.
Later, greases containing lithium stearate were formulated and found to retain their lubricating
properties at both very high and very low temperatures. For the first time, the same grease could
be used for multiple purposes over a wide range of operating conditions. With the advent of rocketry came the search for materials that could withstand the extreme temperatures of high-speed travel through the atmosphere. A ceramic composition containing lithium was developed that expanded very little and resisted cracking during rapid extreme temperature change. This lithium-containing material, "pyroceram," was the forerunner of modern glass-ceramic cookware that resists thermal
cracking.
In 1953, the Atomic Energy Commission (AEC) required large amounts of lithium hydroxide from
which the lithium-6 isotope was separated and reserved for use in the production of thermonuclear weapons. For about five years, the government was the largest consumer of lithium. After the AEC contracts expired in 1960, the lithium industry, faced with vast over capacity, sought desperately to
develop its small commercial markets. Though not an overnight success, it soon became a firmly
established supplier to basic industries such as ceramics, lubrication, aluminum reduction, and pharmaceuticals.
Today, even though lithium products are widely used in households, factories and laboratories,
lithium's presence often goes unrecognized. Lithium may be as close to the average person as
a medicine chest, a television, a swimming pool, or a calculator. Lithium is found in minerals, clays,
and brines located in
various parts of the world. High-grade lithium ores and brines are the present sources for all
commercial lithium operations. Economical brine sources of lithium were rare until several salars
in the
lithium salts.
Initially the two
and later mined spodumene from their large
it into lithium carbonate. Then in 1966 Foote began to recover lithium from their
(
This was the first step towards the brine resources, which combined with solar evaporation is
much more economical, and thus has allowed the price of lithium carbonate to be considerably
lowered and nowadays most of the world’s supply is extracted from various brine deposits.
In 1984 SCL (Sociedad Chilena de Litio, Chemetall Lithium formerly Cyprus Foote)
started lithium carbonate production from brine in the Salar de Atacama (with the final
processing being done near Antofgasta),
In 1995, two important breakthroughs took place in the development of a brine-based resource
for lithium. While still mining spodumene from its
Salar del Hombre Muerto, an Argentine salar containing high uniform concentrations of lithium
with low levels of other contaminants. Concurrently, FMC perfected and commercialized a selective purification process which extracts lithium chloride from the salar brine in a nearly pure form with
minimal processing.
The Salar del Hombre Muerto is located in the high
in the argentinean. FMC has installed production facilities for both lithium chloride and lithium
carbonate from the Salar del Hombre Muerto.
In 1997 SQM (formerly Minsal
Atacama, and cut the selling price of lithium carbonate roughly in half to gain market share.
As result of the lower lithium carbonate price the Cyprus Foote and FMC spodumene operations
were both officially closed by 1998. The other three major producers of lithium ore concentrates, Greenbushes Operations in Australia operated nowadays by Talison Minerals ( formerly owned
by Sons of Gwalia) which is the largest high-grade lithium (spodumene) pegmatite deposit, and
the other two large producers of lithium concentrates are Tanco in Canada and Bikita in Zimbabwe resisted the lower carbonate prices, especially because of their direct application of the spodumene concentrates to the glass industry. A lot of small mineral production sites in
and
Since 2004 lithium carbonate price started to rise, because of the strong demand principally boosted
by the battery application. This forced the actual 3 principal producers ( SQM, Chemetall and FMC) to expand their operations. On the other hand Talisons also increased their output and is selling a big
share of its production to plants in
The interest in lithium is driving new projects such as Salar de Uyuni ( the biggest lithium reserves located
in Bolivia) operated by the Bolivian Government, Salar de Rincon( Argentina) recently sold to the Senpient Group and the minerals depostis owned by Galaxy Resources in Australia, Black Pearl
Minerals ( re-named to Canada Lithium Corporation) and Nordic Mining in Finland.
