Like all alkali metals, lithium is highly reactive and flammable, and is stored in mineral oil. When cut, it exhibits a metallic lustre, but moist air corrodes it quickly to a dull silvery gray, then black tarnish. It never occurs freely in nature, but only in (usually ionic) compounds, such as pegmatitic minerals which were once the main source of lithium. Due to its solubility as an ion, it is present in ocean water and is commonly obtained from brines. Lithium metal is isolated electrolytically from a mixture of lithium chloride and potassium chloride.
Detailed Description of Lithium
Lithium (chemical symbol: Li) is the lightest of all metals. It does not occur as a pure element in nature but is contained within mineral deposits or salts including brine lakes and sea water. Lithium is in reasonable abundance in the earth’s crust. In 2017 the US Geological Survey reported global lithium reserves to be 75 million tonnes of lithium carbonate equivalents which is more than 250 times the current annual global consumption of lithium. The contained concentration of lithium varies significantly between occurrences which determines the economics required to extract the lithium.
Lithium and its chemical compounds exhibit a broad range of beneficial properties including:
The highest electrochemical potential of all metals
An extremely high co-efficient of thermal expansion
Fluxing and catalytic characteristics
Acting as a viscosity modifier in glass melts
As a result, lithium is used in numerous applications which can be divided into two broad categories: chemical applications and technical applications.
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 second-largest) market for lithium globally is for use in batteries.
Talison Lithium produces a chemical-grade lithium concentrate which is ultimately used in lithium 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 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 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 electric passenger vehicles: Hybrid Electric Vehicles, Plug-in Hybrid Electric Vehicles and Electric Vehicles.
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.
OTHER CHEMICAL APPLICATIONS
Lithium chemicals are also used in a variety of other applications including:
Lubricants: lithium is used as a thickener in grease ensuring lubrication properties are maintained over a broad range of temperatures.
Aluminum Smelting: the addition of lithium during aluminum smelting reduces power consumption, increases the bath electrical conductivity and reduces fluorine emissions.
Air Treatment: lithium may be used as an absorption medium for industrial refrigeration systems and for humidity control and drying systems.
Pharmaceuticals: lithium is used in the treatment for bi-polar disorder as well as in other pharmaceutical products.
Lithium products are used directly in technical applications, particularly where lithium products with low iron concentration are necessary to meet the highly specialised requirements of end users. Talison Lithium produces a number of low iron lithium products suitable for technical applications. Currently, the largest global market for lithium is for use in glass and ceramics.
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 high 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.