Battery mining refers to the process of extracting the necessary materials for creating batteries. For most batteries, this involves the necessary materials for an anode, cathode, separator, electrolyte, and two current collectors. For many of these batteries, graphite is used for the construction of the anode, while the cathode is usually manufactured of a combination of lithium, cobalt, oxygen, and a other materials dependent on the battery construction.
Whereas in the lead acid batteries used for combustion engines in the automotive, marine, and pleasure craft industries, lead plates are immersed in a pool of electrolyte.
For most batteries, these materials need to be mined and processed in order to refine them for use in batteries. These materials include:
- Lithium
- Cobalt
- Aluminum
- Vanadium
- Nickel
- Phosphate
- Sulfur
- Manganese
- Graphite
- Lead
Lithium's demand continues to increase due to its role in lithium-ion batteries for consumer electronics and electric vehicles. Lithium is mined from three types of deposits: brines, pegmatites, and sedimentary rocks. The main known global lithium reserves are estimated at 17 million metric tons of which continental brines and pegmatites are the main sources for commercial production.
Lithium extraction from brine sources have proven more economical than production from hard rock ore. As well, the majority of lithium extraction is through brining due to the lower cost of production.
Through the process of brine extraction, a hole is drilled and brine is pumped to the surface. The brine is left to evaporate creating a chemical concoction containing manganese, potassium, borax, and salts, filtered and placed into another evaporation pool. The remaining mix is left for another period of time. This waiting time is dependent on the mine and can take from 12 to 18 months. The remaining mixture is filtered to extract lithium carbonate.
An example of brine extraction lithium.
There are three types of brine deposits: continental, geothermal, and oilfield. The most common are continental saline desert basins, also known as salt lakes, salt flats, or salars. These salars are often located in areas with geothermal activity and made up of sand, minerals with brine, and saline water with a high concentration of dissolved salts. And there are playas, a type of brine deposit which has a surface composed of silts and clays. Playas have less salt than salars.
There are criticisms on the extraction of lithium, which includes increased drought conditions from brine mining threatening local livestock, farming, or vegetation. However, there is little clarity into the overall impact brine extraction of lithium plays in these droughts. There is a concern over the impact of the saltwater used for brining and the influence it can have on local ground water.
Continental brining is the most common form of lithium-containing brine. The majority of the global lithium production from continental lithium brine deposits is in what is known as the "Lithium Triangle", a region of the Andes mountains including parts of Argentina, Chile, and Bolivia.
Bolivia is home to the world's largest deposit of lithium, the Salar de Uyuni, which contains 50 to 70 percent of the world's known reserves. This salar has limited commercial production levels due to state control and regulations.
Geothermal lithium brine deposits make up around 3 percent of known global lithium resources. These deposits are comprised of a hot, concentrated saline solutions that has circulated through crustal rocks in areas of extremely high heat flow and become enriched with elements such as lithium, boron, and potassium.
Image of a geothermal lithium extraction.
Previous to January 2015, there was a plan to produce high-purity lithium carbonate from discharge brine borrowed from geothermal plants operation on the Salton Sea. These plants would have used a reverse-osmosis process to eliminate the need for solar evaporation. As well, PurLucid Treatment Solutions is in the process of developing technology adapted from oilfield extraction for geothermal lithium extraction which is generally thought of as a more environmentally friendly option to traditional geothermal lithium extraction.
Lithium brine deposits can be found in some deep oil reserves, accounting for 3 percent of known global lithium reserves. In these deposits, a brine is pumped into an exhausted oil deposit and lithium is filtered out of the brine. Oilfield lithium extraction has been a way for exhausted oilfields to continue developing economically. A large percentage of the oilfield resources are based in North America and the United States Gulf Coast.
Sedimentary rock is also known as hard rock ore mining, which dominated the lithium mining market before the introduction of brine extraction, which provides a lower cost method of extracting lithium. For lithium mining from sedimentary rock, the most common method of extraction is open pit mining.
In the case of sedimentary rock mining, Australia was the largest producer in 2019 in terms of mine output, the majority of which came from Greenbushes hard rock lithium mine. The overall sedimentary rock deposits account for about 8 percent of known lithium resources.
For sedimentary rock deposits, they are found in clay deposits and lacustrine evaporites. In clay deposits, lithium is found in mineral smectite, the most common type being hectorite, rich in both magnesium and lithium. Many companies are in the research and development phase for clay deposits, but so far companies do not produce lithium from them.
For lacustrine evaporites, the most common form of lithium containing lacustrine deposits are found in the Jadar Valley in Serbia.
Pegmatite is a coarse-grained intrusive igneous rock formed from crystallized magma below the Earth's crust. Pegmatite lithium deposits, also known as hard rock lithium deposits, can contain extractible amounts of elements, including lithium, tin, tantalum, and niobium. Pegmatite mines can be found in Australia, United States, Canada, Ireland, Finland, and the Democratic Republic of Congo.
For lithium extraction from pegmatite, the hard rock ore containing lithium is extracted at open-pit or underground mines using conventional mining techniques. The extracted ore is processed and concentrated using a variety of methods prior to direct use or further processing into lithium compounds.
Image of lithium-containing pegmatite.
Extracting pegmatite lithium from hard rock ore is expensive, meaning such deposits are arguably at a disadvantage compared to brine deposits. However, pegmatite lithium deposits have considerably higher lithium concentrations than brines, meaning deposits with high lithium values may be economically viable, especially with the production of other metals which can help offset costs. Hard rock deposits are also not subject to the long processing times seen at some brine deposits.
Cobalt appears in most commercial lithium-ion batteries due to its properties as an energy dense metal perfect for small-but-powerful batteries. Less than 10 percent of the global cobalt supply occurs as a primary product. The remainder of the cobalt supply is produced as a by-product of primarily copper and nickel mines. More than 65 percent of the global production of cobalt is concentrated in the Democratic Republic of the Congo.
There are human rights concerns surrounding the mining of cobalt in the Democratic republic and the management of these mines. These concerns have driven battery producers and the manufacturers of consumer electronic devices and electric vehicles towards the production and use of batteries which do not require cobalt.
This has seen the replacement of cobalt with materials such as manganese and iron, but these materials lack the energy density of cobalt or nickel. There has also been a move to recycle lithium-ion batteries for their cobalt, but the lithium-ion batteries tend to last long enough that their lifecycle is close to ten years and recycling does not provide enough supply to meet the demand. Solid-state batteries, which, dependent on their structure, require less cobalt than traditional lithium-ion batteries, are also considered a solution to the concerns around cobalt mining.
Aluminum is a component of batteries, including the aluminum-ion battery, and have been included in the idea of new types of batteries, including the aluminum-air battery. The extraction of aluminum takes place in three main stages: the mining of bauxite ore, refining the ore to recover alumina, and smelting the alumina to produce aluminum.
Bauxite is mined by surface mining methods. This include open-cut mining, in which topsoil and overburden are removed by bulldozers and scrapers and the underlying bauxite is minted by front-end loaders, power shovels, or hydraulic excavators. After extraction, a portion of the bauxite ore is crushed, dried and shipped. The other portion is treated after crushing by washing to remove clay, reactive silica, and sand waste. The cleaned bauxite is dried in rotary kilns and then transported to processing plants.
The majority of bauxite ore is refined into aluminum through the Bayer refining process. This is done through four stages: digestion, clarification, precipitation, and calcination.
In the digestion stage, finely ground bauxite is fed into a steam-heated unit called a digester. In there, the ground bauxite is mixed under pressure with a solution of caustic soda which reacts with the bauxite to form a solution of sodium illuminate or green liquor and a precipitate of sodium aluminum silicate.
A visualization of the Bayer process.
In the clarification stage, the green liquor or alumina-bearing solution is separated from the waste. The undissolved iron oxides and silica make up sand and red mud waste, from which the red mud is separated out and the remaining green liquor is pumped through filters to remove any residual impurities.
From the clarification stage, the mixture enters the precipitation stage in which the alumina is separated from the green liquor as crystals of alumina hydrate. To do this, the green liquor is mixed in a tall precipitator vessels with small amounts of fine crystalline alumina, which simulates the precipitation of solid alumina hydrate. The completed solid alumina hydrate is passed on to the next stage while any remaining liquor is returned to the digestors.
And the final stage of the process, the calcination stage, sees the alumina hydrate washed to remove any remaining liquor and dried. The dried alumina hydrate is heated to about 1000 degrees Celsius to dry the water from the crystallization and leaves the alumina a dry, pure white, and sandy material.
From this process, the resulting alumina is transformed into aluminum through a smelting process.
In batteries, vanadium acts as a supercharger by increasing the energy density and voltage of the battery. In the case of electric and hybrid vehicles, the increase of energy density increases the vehicle performance with energy density equating range. Vanadium is also used in vanadium redox flow batteries used for grid energy storage.
Vanadium is also used in the processing of steel to help strengthen it. This use stretches to the automobile industry, in steel girders for infrastructure, used in steel alloys to carry harsh chemicals, is used in infrastructure for nuclear power, and used in aerospace applications to strengthen and lighten the steel used.
Around 85 percent of the vanadium supply comes from South Africa, China, and Russia. Vanadium is usually found within magnetite iron ore deposits and the vanadium is typically mined as a byproduct of the magnetite iron ore and not as a primary mineral. Other common deposits in which vanadium is found include titaniferous magnetite, phosphate rock, and uraniferous sandstone and stiltstone.
Nickel is used in many different types of batteries, including nickel-cadmium and lithium-ion batteries. The use in lithium-ion batteries, the use of nickel is increasing in popularity, especially for use in electric vehicles, as the increased energy density offered by nickel offers an extended range for vehicles at a lower cost. Besides batteries, nickel is also mined for use as an alloy in the manufacturing of stainless steel where nickel increases the strength and anti-corrosive properties of the steel and reduces the magnetic properties of the steel. Nickel is also included as a component in superalloys and specialty steels where it helps withstand high temperatures.
Nickel is naturally occurring as oxides, silicates, and sulfides. It has been estimated more than two million metric tonnes of nickel is produced globally each year. Of that supply, Indonesia is the top nickel producing country, with the Philippines expected to overtake the production in 2020. Matching their production, Indonesia is working to become a global hub for the electric vehicle supply chain, offering their sources of nickel and their proximity to China and Japan to help develop nickel-based batteries.
With the increased interest in the use of nickel in electric vehicle batteries, the nickel mining industry has seen pressure to reduce their overall carbon emissions and to find more environmentally friendly methods of extracting and processing nickel. As well as environmental concerns, Nickel mining and smelting have been reported to produce elevated rates of respiratory problems and deformities within nearby communities and mine workers. Many of these concerns have been attributed to the high loadings of dust in the air with high concentration of potentially toxic metals.
Nickel sulfide is traditionally mined through underground techniques similar to copper mining, although some is mined through open pit mining. The mining of nickel containing laterites is done through earth-moving operations using large shovels, draglines, or front-end loaders extracting the nickel-rich strata and discarding the boulders and waste material. Similar to copper, nickel is extracted through a smelting process using high temperature refractories but also requires increased cooling.
Image of an open-pit nickel mine.
Some nickel mines produce nickel primarily, while some mines produce nickel as a by-product of other metals. Most of those nickel reserves are in the form of lateritic nickel ore deposits. Most of the current nickel is produced from nickel sulfide ores. There are nickel deposits also found in manganese nodules found in the deep sea, which are estimated to be over 290 million tonnes but only accessible through deep-sea mining techniques not currently available. And 80 percent of the known nickel deposits mined have been unearthed in the past thirty years.
To extract nickel from sulfide ores, the ores are crushed and ground to liberate the nickel minerals. This is mixed with special reagents and agitated by mechanical and pneumatic devices the produce air bubbles. As the air bubbles rise through the mixture, the sulfide particles adhere to their surfaces and are collected as a concentrate. The waste material is put through a second cleaning step before it is discarded. Nickel often goes through a flotation and magnetic separation technique to bring the nickel concentrates to the top before it is smelted.
Being free of sulfur, laterite nickel deposits do not cause a pollution problem in the same way sulfide ores do, although they require a substantial energy input in the mining, a process which has also been considered to have a detrimental effect on soil and erosion. And due to the large amount of water present in laterite ores, drying and removal of chemically bound water are important operations in the extraction of nickel carried out through rotary-kiln furnaces. After drying, the oxide is reduced to nickel metal in electric furnaces in a smelting process.
Phosphates are used in lithium-iron-phosphate batteries, which are expected to replace lithium-manganese-cobalt-oxide batteries in the stationary storage markets. The lithium-iron-phosphate batteries tend to be more available, at lower cost, and with higher recycling capabilities than lithium-manganese-cobalt-oxide batteries.
The mining of phosphate is primarily done in China, Morocco, and the United States. Much of the phosphate is mined in open pits or surface and underground mines. Besides its use in batteries, phosphate is generally mined for use in fertilizers, animal feed, and detergents.
Sulfur is gaining interest for use in batteries due to the lithium-sulfur battery which presents itself as a possible replacement for lithium-ion batteries. The lithium-sulfur battery is capable of carrying as much as six times the energy per a given weight compared to a lithium-ion battery and are made from inexpensive and readily available materials. However, the amount of energy tends to cause lithium-sulfur batteries to break down under the stress. New technologies have presented a possibility to develop lithium-sulfur batteries that will not break down under the strain of the energy. The technology is known as an expansion tolerant electrode structure.
If capable, sulfur, as the 16th most abundant element on Earth with around 70 million tonnes produced each year, presents a way of creating more inexpensive batteries.
When mining, sulfur has been found in volcanic regions and salt domes. Sulfur is also produced as by-products resulting from other industrial processes such as oil refining. And sulfur is found in fossil resources such as natural gas and petroleum. In sulfur mining, the Frasch process, developed in the 1800s, is still the more commonly used method. This involves using super-heated water into a sulfur deposit to melt and come up to the surface by way of compressed air. During the later part of the 20th century, mining or recovering sulfur as a by-product of natural gas production or oil refinement has become more significant in terms of overall production.
Manganese is the 12th most abundant element and in high global demand because of the minerals varied applications in the production of steel and high-capacity batteries. Around 18.5 million tonnes of manganese is produced globally each year. The major producing countries of manganese include South Africa, Australia, China, Gabon, Brazil, and Ukraine. But of the known global reserves, 70 percent is contained in the Kalahari District of South Africa.
For batteries, manganese is used in nickel-metal hybrid (NiMH) electric vehicle batteries (which are most commonly used in Toyota Prius batteries), lithium-ion (Li-ion) batteries, and newer lithiated manganese dioxide (LMD) batteries. These LMD batteries use 61 percent of manganese in its mix and only 4 percent lithium. The benefits of LMD include higher power output, thermal stability, and improved safety compared to regular lithium-ion batteries. LMD batteries are currently in use in the Chevy Volt and the Nissan Leaf.
An example of a manganese mine.
Much of the manganese mined is available at the surface level and mining for it is not an expensive enterprise. The technical simplicity allows for cost control that is not possible for more complex methods of production. Manganese can also be found in cobbles or clasts and hydrothermal veins. Both of these can be mined using relatively inexpensive methods.
Graphite is a key raw material used for the anode segment in many battery constructions, including use in lithium-ion batteries. With the increase in sale of battery-powered technologies, including electric vehicles, the demand for graphite continues to rise. The graphite used in these applications often either synthetic and natural graphite. The top graphite producing countries include China, Mozambique, Brazil, Madagascar, Canada, India, Russia, Ukraine, Norway, and Pakistan.
A miner holding a piece of graphite ore.
Graphite extraction is dependent on the weathering of ore and the proximity of the ore to the surface. Most companies mining graphite use open pit mining techniques or underground mining techniques.
The open pit mine relies on a process called quarrying where graphite is obtained through breaking rocks with explosives or through drilling. Underground mining is used when graphite ore is deep underground. The underground mining process includes drift mining, hard rock mining, shaft mining, and slope mining.
Lead has been used in lead-acid batteries since they were invented in 1859 by physicist Gaston Planté. These batteries offer low energy-to-weight and low energy-to-volume ratios but relatively large power-to-weight ratio compared to other battery types. This, in part, is why they are used for motor vehicles to provide the high current required by starter motors. The lead-acid battery was the first rechargeable battery for commercial use.
Example of a lead-acid battery.
In the lead-acid battery, a grid structure is made of a lead alloy, with pure lead being too soft to support itself. The most common additives for these alloys include antimony, calcium, tin, and selenium. And these batteries are arranged in a grid of cells which are connected to produce a stronger overall battery.
Beside batteries, lead is used in sound barriers, as a shield against x-rays, and a long-lasting roofing material because of its density and its corrosion resistance. Of the lead materials are used, only about half use lead produced from mining. The rest is obtained from recycling, in large part from recycling car batteries. The largest producers of lead materials in the world are Australia, the United States, China, and Canada.
In mining, lead is extracted from ores dug from underground mines. Of the more than 60 minerals that contain lead, only galena, cerussite, and anglesite are commercially viable. The lead is usually found in conjunction with other metals such as silver and zinc, and because of this most lead is mined as a by-product of these other more valuable metals.
Examples of the process of extracting and refining lead.
The process of extracting the lead from the ore is multi-step. First the lead ore is ground into particles smaller than 0.1 millimeter. The lead powder is then put through a flotation process, mixing lead ore with water, and the addition of pine oil and air bubbles from agitation which forms an oil froth that brings the lead ore to the surface. This froth is then skimmed and filtered to remove the water.
After skimming, the powder is sintered at over 2500 degrees Fahrenheit to oxidize impurities such as sulfur. The resulting powder is further heated in a blast furnace with carbon producing molten lead drawn off into lead molds. At this stage, the lead is about 95 percent pure and can be further refined to reach greater than 99 percent purity through a process of melting and skimming impurities.
