Lithium is a relatively abundant metallic element and is widely distributed at very low concentrations in various mineral compounds and salts in the earth’s crust and in seawater.
Lithium is never found in its elemental form in nature due to its reactivity, but occurs in over 100 different mineral compounds which pose no threat to health. The USGS estimated global reserves of lithium at 14 million tonnes in 2018, however, deposits which are economically viable to exploit are relatively rare and fall into two broad categories – hard rock (including clays) and brines.
| Chemical symbol | |
|
Chemical symbol |
Li |
| Discovered | |
|
Discovered |
1817 in Sweden by Johan August Arfvedson in the mineral petalite (see below). The name is derived from the Greek, “lithos” meaning stone. |
| Description | |
|
Description |
A silvery-white to grey Group 1 alkali metal with a metallic lustre when fresh |
| Atomic number | |
|
Atomic number |
3 |
| Atomic Weight | |
|
Atomic Weight |
6.94 - the lightest of all metals, floats on water |
| Density | |
|
Density |
0.534g/cm3 – the least dense of all elements which are not gases at 20°C |
| Hardness | |
|
Hardness |
Very soft (0.6 on Mohs hardness scale, Talc = 1, Diamond = 10) |
| Melting point | |
|
Melting point |
180.54°C (lithium has the highest specific heat capacity of any solid element) |
| Boiling point | |
|
Boiling point |
1,342°C |
| Electrical resistivity | |
|
Electrical resistivity |
9.5mΩ cm – Very low resistivity, making Li an excellent conductor of electricity |
| Electronegativity | |
|
Electronegativity |
1.0 – Li has one of the lowest electronegativities of all elements, i.e. it readily loses its electrons to more electronegative elements which is a key property for its use in batteries. It also has the highest electrochemical potential of all metals |
| Occurance | |
|
Occurance |
Li is never found in nature in its elemental form, but always in compounds such as rock forming minerals or salts (including brines and seawater) |
| Li minerals | |
|
Li minerals |
More than 100 known Li-bearing minerals, although only a handful are currently economic to extract |
| Li chemicals | |
|
Li chemicals |
Commercially produced lithium chemicals include lithium carbonate, lithium hydroxide monohydrate (“lithium hydroxide”), lithium bromide, lithium chloride and butyl lithium |
Within the hard rock category, spodumene, as found at Savannah’s Barroso Lithium Project in Portugal, has been by far the most common lithium bearing mineral exploited in economically viable deposits to date. Spodumene is typically found in pegmatites which are igneous rocks similar in mineral composition to granites but with very coarse grain sizes. The Barroso Lithium Project will produce the mineral spodumene, not elemental lithium. Spodumene is non-toxic and non-reactive.
|
Mineral name |
Chemical formula |
Li Content (Li%) |
Notes |
|---|---|---|---|
| Spodumene | |||
|
Spodumene |
LiAlSi2O6 |
3.7 |
The most abundant Li-bearing mineral found in economic deposits, such as Mina do Barroso, Portugal and Greenbushes in Australia. |
| Amblygonite | |||
|
Amblygonite |
(Li,Na)AlPO4(F,OH) |
3.4-4.7 |
Has previously been exploited for Li in Zimbabwe. |
| Eucrytite | |||
|
Eucrytite |
LiAlSiO4 |
2.1-5.5 |
Has previously been exploited for Li in Zimbabwe. |
| Hectorite | |||
|
Hectorite |
Na0.3(Mg,Li)3Si4O10(OH)2 |
0.5 |
A smectite clay mineral currently being evaluated as a potential economic source of Li. |
| Jadarite | |||
|
Jadarite |
LiNaSiB3O7(OH) |
7.3 |
Discovered in Serbia in 2007. Not currently worked, but being evaluated as a potential economic source of Li. |
| Lepidolite | |||
|
Lepidolite |
K2(Li, Al)5-6{Si6-7Al2-1O20} |
1.4-3.6 |
An uncommon form of mica found in pegmatites. |
| Petalite | |||
|
Petalite |
LiAlSi4O10 |
1.6-2.3 |
Often occurs with lepidolite in pegmatites. |
| Zinnwaldite | |||
|
Zinnwaldite |
KLiFeAl(AlSi3)O10(F,OH)2 |
1.6 |
Another Li bearing mica found in pegmatite and quartz veins. |
Source: British Geological Survey, Company
Brines (fluids containing dissolved solids) can potentially contain economically viable concentrations of lithium. Continental brines, found in poorly draining inland basins have become significant production centres for lithium, particularly where high solar evaporation rates can be used as a low cost means of increasing the lithium concentration once the brine is at surface prior to subsequent processing. Work is also underway assessing the potential to extract lithium from brines associated with geothermally active areas and oilfields, where brines are extracted as a waste product from underground formations along with oil and gas.
|
Deposit class |
Deposit type |
Description |
Typical grade |
Examples |
|---|---|---|---|---|
| Hard rock | ||||
|
Hard rock |
Pegmatites |
Coarse-grained igneous rock formed during late-stage crystallisation of magmas |
1.0-4% Li2O |
Greenbushes, Australia; Mina do Barroso, Portugal |
|
Hectorite |
Lenses of smectite clay in association with volcanic centres |
0.4% Li2O |
Kings Valley, USA; Sonora, Mexico |
|
|
Jadarite |
Altered basinal sediments |
1.5% Li2O |
Jadar, Serbia |
|
| Brine | ||||
|
Brine |
Continental |
Salt pans/salars in enclosed basins with enriched lithium solutions |
0.04-0.15% Li |
Clayton Valley, USA; Salar de Atacama, Chile; Salar de Hombre Muerto, Argentina |
|
Geothermal |
Enriched lithium bearing solutions associated with geothermally active areas |
0.01-0.035% Li |
Salton Sea area, USA |
|
|
Oilfield |
Lithium enriched solutions removed as waste product from active oilfields |
0.01-0.05% Li |
Smackover oilfield, USA |
Source: British Geological Survey, Company
Trade in lithium is largely centred around key lithium raw materials and chemicals such as spodumene concentrate, lithium carbonate and lithium hydroxide which vary significantly in their lithium content. In parallel with this, reference data relating to lithium grades in mineral assays and ore resources and reserves for hard rock and brine projects are also reported using a number of differing measurement units, e.g. parts per million (ppm) Li and percentages of Li, Li2O, or lithium carbonate. To normalise this data, market participants will often also report data in terms of “lithium carbonate equivalent” or “LCE” so that information can be easily compared on a like-for-like basis. Conversion to LCE is based upon the formulae in the table below.
|
To convert from |
Chemical formula |
Multiply by to convert to |
||
|---|---|---|---|---|
|
Lithium (Li) content |
Lithium Oxide (Li20) content |
Lithium carbonate Equivalent (LCE) |
||
| Lithium | ||||
|
Lithium |
Li |
1 |
2.153 |
5.323 |
| Lithium Oxide | ||||
|
Lithium Oxide |
Li2O |
0.464 |
1 |
2.473 |
| Lithium carbonate | ||||
|
Lithium carbonate |
Li2CO3 |
0.188 |
0.404 |
1 |
| Lithium hydroxide monohydrate | ||||
|
Lithium hydroxide monohydrate |
LiOH.H20 |
0.165 |
0.356 |
0.880 |
Source: British Geological Survey
Despite its rapid growth profile in recent years, the lithium market remains a modestly sized speciality chemical market and lithium product pricing remains relatively opaque in comparison to the much larger, more liquid, markets for precious, base and bulk metals.
However, prices are published by several providers for spodumene and a number of lithium chemicals including lithium carbonate, lithium hydroxide and lithium chloride. These prices are provided in various currencies and based on despatch or delivery at a number of relevant locations, e.g. Australia, China, Europe.
The majority of lithium material is bought and sold under long-term contractual agreements with prices formulae based on published prices adjusted for various factors including product quality and delivery/despatch location. Trade in the spot market is relatively minor at present, but this may change if the market expands significantly over the next decade as expected.
Prices for chemical grade lithium carbonate, lithium hydroxide and Spodumene, 2018-21 (US$/metric tonnes):
- Spodumene (RHS)
- Lithium Carbonate (LHS)
- Lithium Hydroxide (LHS)
Sources: SP Angel/AsiaMetals