Lithium
The lithium atom is the smallest of the metal atoms in the periodic table. It is the lightest and most reactive of the alkali metals, it floats on water but strongly reacts with water yielding lithium hydroxide and hydrogen gas. Lithium is a soft silver-grey metal, yet when combined with metals such as magnesium, it forms a very strong alloy. Lithium is also highly reactive, reacting with water, oxygen, carbon dioxide and nitrogen at room temperature. In contrast, lithium compounds, are very stable.
Element Properties
| Atomic Number: | 3 | Atomic Radius: | 182 pm (Van der Waals) |
| Atomic Symbol: | Li | Melting Point: | 180.5 °C / 356.9 °F / 453.65 K |
| Atomic Weight: | 6.94 | Boiling Point: | 1330 °C / 2448 °F / 1603 K |
| Electron Configuration: | [He]2s | Oxidation States: | +1 (a strongly basic oxide) |
| Hardness (Mohs’ scale) | 0.6 | Density at 20 °C in g/cm3 | 0.53 |
| Standard Electrode Potential in V | -3.045 | Electrical conductivity in 10^6 (Ohm.cm) | 0.108 |
| Specific heat in J/(g.K) | 3.582 | Ionization potential in eV | 5.392 |
Lithium was first identified in 1817, one of several to be found during a golden age of element discovery. In 1800, the Brazilian scientist José Bonefácio de Andrada e Silva (1763-1838) discovered two new minerals on the Swedish island of Utö which were called petalite and spodumene. But it was only in 1817 that the Swedish scientist Johan August Arfvedson (1792-1841) who worked in the laboratories of the renowned chemist and professor of medicine and pharmacy, Baron Jöns Jacob Berzelius (1779-1848), was able to solve the problems regarding inexplicable differences in the analyses of these minerals. He isolated a sulphate which did not contain any of the known alkali or alkaline earth metals. The new element he found was finally named “lithium”, derived from the Greek word “lithos” for stone. With the discovery of this new element, another gap in the periodic table was filled.
Due to lithium’s high reactivity, metallic lithium is not found as such in nature. Traces of this element are present in nearly all minerals, brines, clays and sea water. The crust of earth contains an average of about 20 parts per million (ppm) or 0.0020% while sea water typically contains 0.18ppm Li (0.000018%).
Talison Lithium’s Greenbushes Mine (image courtesy of Tianqi Lithium)
Lithium minerals occur mainly in granitic pegmatites, which are coarse-grained igneous rocks comprised mainly of quartz, feldspar and mica, with spodumene and other lithium minerals occurring as accessory minerals. Lithium-bearing pegmatites are typically highly zoned, with the lithium minerals generally occurring towards the mid-section of the pegmatite. Tantalum, tin and beryl minerals, if present, are typically found on the periphery.
The main lithium-bearing minerals found in pegmatites are spodumene, petalite, lepidolite, amblygonite/montebrasite and eucryptite. Typical concentrations of lithium in pegmatites range from 1% to over 4% Li2O. Spodumene is the most important lithium-bearing mineral in terms of production because deposits are large, the lithium content is relatively high (Table 1) and the ores are comparatively easy to process. Spodumene was the principal source of lithium for lithium carbonate production until the mid-1990s. Petalite and lepidolite are also recovered in economic quantities.
Currently, Western Australia, China and Zimbabwe are the main processors and suppliers of these hard rock minerals.
Mineral | Formula | Theoretical Li2O content (%) | Typical Li2O content (wt %) |
Petalite | Li2O.Al2O3.8SiO2 / LiAl(Si4O10) | 4.5 | 3.0-4.5 |
Spodumene | Li2O.Al2O3.4SiO2 / LiAl(Si2O6) | 8.03 | 1.0-7.0 |
Amblygonite | (Li,Na)Al(PO4)(F,OH) | 10.1 | 8.0-9.0 |
Lepidolite | K(Li,Al)3(AlSi4O10)(OH,F)2 | 4.1 | 3.0-4.0 |
Eucryptite | Li2O.Al2O3.2SiO2 / (LiAl(SIO4) | 11.9 | 5.0 |
Zinnwaldite | KLiFeAl(ALSi3)O10(F,OH)2 | 3.41 | 2.0-5.0 |
Source: Lithium: Production and application of a fascinating and versatile element, Chemetall GmBH, Jurgen Deberitz
Spodumene is a lithium aluminium silicate mineral. It undergoes an irreversible phase transformation at about 1,080ºC to tetragonal beta phase and exhibits a very low thermal coefficient of expansion. The change is accompanied by a 30% increase in volume and a drop in relative density from 3.2 to 2.4.
Petalite is also monoclinic and, when heated, it converts to beta spodumene quartz in the solid solution phase. It is especially useful for direct application in the glass industry because of the low iron content.
Lepidolite is a complex lithium mica and monoclinic. It was originally the most widely-used lithium mineral but demand has fallen because of the significant fluorine content.
The semi-precious stone kunzite is chemically pure spodumene. The pink coloration is caused by traces of manganese. Another variety is hiddenite which is greenish (chromium impurities).
The Salar de Atacama brine (image courtesy of SQM)
High concentrations of lithium are found in brines at numerous playa lakes or salars in North and South America and in China. Lithium is also found in brines in certain areas of geothermal activity, such as such as western USA, Europe, New Zealand and Iceland, and in certain oilfield brines. Sea water contains lithium but the concentrations are very low and only certain enclosed seas, such as the Dead Sea, which has little inflow and high evaporation rates, have higher concentrations of lithium, however these are still well below that at the salars.
Lithium brines from salars are also a major source of lithium compounds. Lithium was first extracted commercially from brines at the Silver Peak deposit in the USA in 1966, although lithium was extracted as a by-product of potassium production at Searles Lake, also in the USA, from 1936 to 1978. In 1969 the Chilean Instituto de Investigaciones Geologicas identified unusually high concentrations of potassium and lithium at the Salar de Atacama in northern Chile and, after much research and development, Sociedad Chilena de Litio (SCL) began commercial production of lithium carbonate from the Salar de Atacama in 1986. In 1994 the Foote Mineral Company (FMC) began production of lithium chloride from the Salar de Hombre Meurto in Argentina followed shortly after by production of lithium carbonate by Sociedad de Quimica (SQM) at the Salar de Atacama in 1995. The development of lithium brine resources in Qinghai and Tibet provinces in China began in the early 2000s.
Salars are large, dry lake beds where brines are located just under a layer of crusted salt deposits. Lithium-containing salts are concentrated over time to reach levels of 200ppm to over 2,000ppm. Lithium brines occur in salars which have formed as closed or restricted drainage basins where the evaporation rate is higher than the precipitation. Most such basins are located at high altitude in major mountain chains, such as the Andes. Most salars have a salt crust carrying some sand, clay and other minerals; the salt crust is porous and the interstices contain the salt brines.
The Zabuye salt lake in Tibet, China, is of interest because it is the only known location where Zabuyelite, a natural lithium carbonate, is precipitated naturally.
Production of lithium from seawater, geothermal brines and oilfield brines has been, and continues to be, investigated.
The lithium content of underground brines is low, but is very large, and substantial reserves of lithium occur in seas around the world, although again concentrations are very low. In addition, pegmatites containing lithium minerals have been identified and worked in France, India, Mozambique, Sweden and Ukraine, but reserve data for these and other deposits is lacking. Increasing consumption and prices for lithium products has prompted increasing exploration for, and assessment of, new lithium deposits, therefore reserve data for lithium has the potential to be further revised in the future.
Lithium Americas’ Thacker Pass project (image courtesy of Lithium Americas)
Hectorite – (Mg,Li)3Si4O10(OH)2NaO.3(H2O)4 – is a lithium-magnesium-sodium montmorillonite, usually containing 0.3-0.6% Li. Numerous deposits occur in Nevada, California, Utah, Oregon, Wyoming, Arizona and New Mexico in the USA. Hectorite is unique in that it is a commercial authigenic lithium montmorillonite clay mineral of telethermal origin. It modifies liquid systems to a gel-like structure through its properties of dispersibility, suspension and thickening.
Owing to continuing exploration, in recent years identified lithium resources around the world have increased substantially. The United States Geological Survey (USGS) estimates total identified lithium resources at over 86 million tons (Mt) (equal to 454.5Mt of lithium carbonate equivalent (LCE)) in 2020, with reserves totalling 21Mt Li (111.8Mt LCE) (see Table 2).
Table 2: Lithium mine production (2020), reserves and resources in tonnes (USGS) | |||
Country | Production | Reserves[note 1] | Resources |
Argentina | 6,200 | 1,900,000 | 19,300,000 |
Australia | 40,000 | 4,700,000 | 6,400,000 |
Austria | – | – | 50,000 |
Bolivia | – | – | 21,000,000 |
Brazil | 1,900 | 95,000 | 470,000 |
Canada | 0 | 530,000 | 2,900,000 |
Chile | 18,000 | 9,200,000 | 9,600,000 |
China, People’s Republic | 14,000 | 1,500,000 | 5,100,000 |
Czech Republic | – | – | 1,300,000 |
DR Congo | – | – | 3,000,000 |
Finland | – | – | 50,000 |
Germany | – | – | 2,700,000 |
Ghana | – | – | 90,000 |
Kazakhstan | – | – | 50,000 |
Mali | – | – | 700,000 |
Mexico | – | – | 1,700,000 |
Namibia | – | – | 50,000 |
Peru | – | – | 880,000 |
Portugal | 900 | 60,000 | 270,000 |
Serbia | – | – | 1,200,000 |
Spain | – | – | 300,000 |
United States | 870[note 2] | 750,000 | 7,900,000 |
Zimbabwe | 1,200 | 220,000 | 500,000 |
World total | 82,000 | 21,000,000 | 86,000,000+ |
Note 1: 6 November 2011. By USGS definitions, the reserve base “may encompass those parts of the resources that have a reasonable potential for becoming economically available within planning horizons beyond those that assume proven technology and current economics. The reserve base includes those resources that are currently economic (reserves), marginally economic (marginal reserves), and some of those that are currently subeconomic (subeconomic resources).”
Note 2: In 2013
Lithium resources map
Lithium can be processed to form a variety of chemicals, including lithium carbonate, lithium bromide, lithium chloride, butyl lithium and lithium hydroxide. The fastest growing and largest market for lithium globally is for use in batteries.
BATTERIES
The two main lithium battery types are:
- Primary (non-rechargeable): including coin or cylindrical batteries used in calculators and digital cameras. Lithium batteries have a higher energy density compared to alkaline batteries, as well as low weight and a long shelf and operating life.
- Secondary (rechargeable): key current applications for lithium batteries are in e-mobility, powering cell phones, laptops, other hand-held electronic devices, power tools and large format batteries for electricity grid stabilisation. The advantages of the lithium secondary battery are its higher energy density and lighter weight compared to lead acid, nickel-cadmium and nickel-metal hydride batteries.
A growing application for lithium batteries is as the power source for a wide range of electric vehicles including electric bikes / scooters, buses, taxis, trucks as well as passenger electric vehicles. There are three main categories of passenger electric vehicle (EV): a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV) and a battery electric vehicle (BEV).
Electrification of vehicles is strongly supported by governments around the world due to the increasing political and consumer focus on climate change and energy security. The introduction of mass produced passenger electric vehicles has the potential to significantly increase the future consumption of lithium.
Lithium chemicals are also used in a variety of other applications including:
- Air treatment: lithium may be used as an absorption medium for industrial refrigeration systems and for humidity control and drying systems.
- Aluminum smelting: the addition of lithium during aluminum smelting reduces power consumption, increases the bath electrical conductivity and reduces fluorine emissions.
- Aluminium-lithium (Al-Li) alloys: Al-Li alloys are lighter than conventional high-strength aluminium alloys and can be used to manufacture aircraft.
- Construction materials: lithium carbonate can be used in fast setting cement and mortars, e.g. self-leveling floor screeds.
- Glass: lithium oxide can be used to create high-durability glass products where thermal shock resistance is important.
- Lubricants: lithium is used as a thickener in grease ensuring lubrication properties are maintained over a broad range of temperatures.
- Pharmaceuticals: lithium is used in the treatment for bi-polar disorder as well as in other pharmaceutical products.
GLASS AND CERAMICS
- Glass: including container glass, flat glass, pharmaceutical glass, specialty glass (used in touch screens) and fibreglass. These glass products may be designed for durability or corrosion resistance or for use at high temperatures where thermal shock resistance is important. The addition of lithium increases the glass melt rate, lowers the viscosity and the melt temperature providing higher output, energy savings and moulding benefits.
- Ceramics: including ceramic bodies, frits, glazes and heatproof ceramic cookware. Lithium lowers firing temperatures and thermal expansion and increases the strength of ceramic bodies. The addition of lithium to glazes improves viscosity for coating, as well as improving the glaze’s colour, strength and lustre.
- Specialty Applications: including induction cook tops and cookware. Lithium’s extremely low co-efficient of thermal expansion makes these products resistant to thermal shock and imparts mechanical strength.
OTHER TECHNICAL APPLICATIONS
Lithium is also used in a variety of metallurgical applications including:
- Steel castings: the addition of lithium to continuous casting mould fluxes assists in providing thermal insulation and lubricates the surface of the steel in the continuous casting process.
- Iron castings: in the production of iron castings, such as engine blocks, lithium reduces the effect of veining, thereby reducing the number of defective casts.
