Lithium

Li

Lithium minerals, lithium and its compounds have assumed great military and civilian significance after the Second World War.

The History Says

The name comes from the Greek word lithos. Lithos translates to 'stone'. It was given this name because it was first discovered from a mineral rather than a plant. Lithium was first discovered and defined by by J.A. Arfvedson in 1817 when he did an analysis of a mineral he had found. This mineral, petalite (LiAl(Si₂O₅)₂), was first found by Brazilian scientist José Bonifácio in 1800. Arfvedson was never able to fully isolate lithium, and it wasn't until 1855 that it was isolated, by W.T. Brande. Lithium was first produced commercially in 1923, by Metallgesellschaft AG.

The Present Scenario

Lithium stearate is fast replacing zinc stearate in body and face powder. It has better oil and moisture absorption power than most of the other stearates. Lithium stearates or other lithium soaps produced by reacting lithium hydroxide with fatty acids are used for the manufacture of lubricating grease compounded with petroleum and other lubricating oils.

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LITHIUM MINERALS are few. Only thirteen are known, of which several are of commercial importance. These are:

• Spodumene LiAl(SiO₃)₂ containing 4 to 8 per cent lithia.
• Amblygonite, LiAl(F,OH)PO₄, containing 8 to 10 per cent lithia.
• Lepidolite, lithium mica. It has a complex composition which may be written as KliAl (OH,F)₂Al(SiO₄)₃, or K₂Li₄Al₂F₄Si₈O₂₂. It carries 2 to 4 per cent lithia.
• Zinnwaldite, lithium iron mica. It also has a complex chemical composition, Le₂K₂Fe₂Al₄Si₇O₂₄. It contains 2 to 3.5 per cent lithia.
• Petalite, LiAl(Si₂O₅)₂, containing 2 to 4 per cent lithia.
• Triphylite, Li(Fe, Mn)PO₄, containing 2 to 6 per cent.
• Lithiophilite, Li(Mn, Fe)PO₄, containing 2 to 6 per cent lithia.

Out of the lithium minerals, lepodilite has wide-spread occurrence, but it is less favoured by industries than spodumene and amblygonite because of the lower percentage of lithia. Sondumene has become the chief commercial source of lithium because of its regular supply and comparatively high Li₂O content. Petalite is also found in large quantities but its Li₂O percentage is similar to lepidolite. Others have restricted occurrence. Lithium minerals are mostly found in pegmatites.

Industrial Applications

Lithium minerals, lithium and its compounds have assumed great military and civilian significance after the Second World War. Some of the lithium compounds are considered to have been used as rocket propellants and in nuclear reactors. Lithium has two stable isotopes with mass numbers of 6 and 7 with relative abundance of 7.5 and 92.5%. The former isotope is used for the production of tritium, extra heavy hydrogen, an intermediate explosive in the manufacture of hydrogen bombs. It serves as well in the preparation of lithium deutride, which is also used in the manufacture of the hydrogen bomb.

It is suggested that lithium perchlorate is used as a rocket propellant. Lithium - 7 metaphosphate and pyrophosphate are valuable constituents in fused salt nuclear breeder blankets because of their relatively high thermal stability and low absorption of thermal neutrons by phosphorous compounds. Lithium hydroxide and lithium onropound of lithium hydride yields 22.5 cubic feet of gas and that of lithium boro-hydride 66 cubic feet.

Ceramics and Glass

Lithium minerals are used in glass and ceramic industries for their lithia content. Lepidolite, spodumene and amblygonite are used along with glass sand-batch for the manufacture of lithium glass. It has the lowest melting point and lowest annealing temperature of all alkali glasses. Lithium reduces its co-efficient of expansion. It is reported that lithium minerals have also been used in the manufacture of ceramic bodies.

Chemicals

Lithium minerals are mainly utilized in the manufacture of lithium carbonate which is the starting point for the manufacture of various chemicals which are used in lubricating greases, ceramics, air-conditioning and refrigeration, alkaline storage battery, bearing and welding aluminium, bleaching, chlorination of water in swimming pools and several other purposes.

Lithium chloride is largely used in refrigeration and air-conditioning plants as it is one of the most hygroscopic of all inorganic salts. Lithium hydroxide is used for absorbing carbon dioxide in submarines and as a constituent of respirators. Chloride and fluoride compounds are used in welding and brazing.

Dry lithium hypochlorite is used as a bleach in laundries and for chlorination of swimming pools.

The uses of lithium chemicals are expanding in their many ramifications.

Metallic

It finds small use in alloying with metals of higher melting points like Cr, Al, Mg, Cu, Pb and Zn. It imparts toughness and tensile strength to the alloy. Lithium is also used as a scavenging material for metallic minerals and gases in the metallurgy of several metals.

Lithium Around Us

Lithium is found throughout the natural world. The below tables its density in the world around us

Abundance	ppb (by weight)	ppb (by atoms)
Universe	6	1
Sun	0.06	0.01
Sea Water	180	160
Stream	3000	430
Crust of the Earth	50,000	No Data Found

It occurs in nature ususally in one of these three mineral forms

Mineral Name	Equation
Spodumene	LiAlSi2O6
Lepidolite	K2Li3Al4Si7O21(OH+F)3
Petalite	LiAlSi4O10

Note : Listed in order of rate of occurance

World Resources

Spodumene is worked in North Carolina and South Dakota in the USA and Quebec in Canada.

Quebec contains one of the largest spodumene deposits in the world. The ore body consists of an exhaustive group of parallel pegmatite dykes containing the proved reserves of more than 20 million tonnes averaging 1.15% Li₂O. It is sold after processing in the form of lithium carbonate. Both open pit and underground methods of mining are employed.

A small quantity is mined in the Paraiba, Rio Grande de Norte, and Ceara in Northern Brazil.

Amblygonite is produced in Sweden; Quebec Great Slave Lake north-west territories, Canada; and Bikitia in Rhodesia.

Pegmatite of Bikitia is probably the only pegmatite zone in the world containing rich deposits of lithium ores. One large pit contains entirely of petalite and crystals as long as 3 metres have been found. Another pit is rich in lepidolite. Eucryptite (LiS,LlO₄) has been found in workable quantity in several pits.

Cesium minerals are associated with lithium ores. The Republic of South Africa is also an important producer of spodumene. Large deposits of petalite have been located at Karibib in South-West Africa.