"New Oil of the XXI Century". Lithium is a strategic resource for the future
Lithium mining in Bolivia. Source: nat-geo.ru
Strategic lithium
The increase in lithium consumption by the military industry is inevitable for many reasons.
Firstly, currently only lithium-ion batteries can store a lot of electricity in relatively small amounts.
Secondly, the military is constantly increasing the number of gadgets that need energy, which in the field can often only be provided by rechargeable batteries. The exoskeletons coming to the troops, in general, became possible only due to the miniaturization of power supply systems.
Third, heavy equipment is gradually shifting to hybrid drives, requiring somewhere to store energy from generators and regenerative braking. Hybrids enter the army not because of the now fashionable decarbonization - the refusal to burn hydrocarbon fuels, but because of the high secrecy of such decisions.
On the battlefield, a hybrid tank or infantry fighting vehicle can turn off the engine-generator and move exclusively on the electricity stored in the batteries. That is, armored vehicles do not smoke, do not make noise, and are not so clearly illuminated in the infrared range. And, of course, hybrid armored vehicles save fuel and engine resource.
Source: army.mil
Similar developments already exist abroad in pre-production form.
For example, in the USA they are working on a hybrid BMP Bredley-HED equipped with Modular EX-Drive electric transmission and lithium-ion battery units. Several years ago, the Krymsk hybrid armored personnel carrier was tested in Russia, and now work is underway on a special wheeled platform-O chassis with an electric transmission. Despite the high fire hazard of lithium, this metal will take an important place in the military-technical industry in the foreseeable future. This means that lithium deposits will become strategic objects.
Lithium from salts
In nature, lithium, due to its high activity, is not found in free form - only in the composition of dissolved salts and solid minerals.
The main sources of lithium are salt lakes in arid countries, which are related to hydrothermal lithium raw materials. In this regard, Chile was the most fortunate, on whose territory a large lithium deposit is located - the Salar de Atacama salt marsh. The surface area of this dried up lake reaches 3 square meters. km. And the approximate reserves of lithium metal hidden in the salt crust are estimated at almost 000 million tons.
Indeed, it is not for nothing that Chile is called the "lithium Saudi Arabia." In recent decades, this South American country has provided up to 43% of the world's lightest metal consumption.
Not only a giant salt marsh, but also the burning sun coupled with a desert arid climate became an important link in the Chilean lithium miracle. Precipitation in this area falls the least of all than anywhere else in the world - only 10 mm / year. This causes intensive evaporation of moisture (up to 3 mm / year). That is why only an extremely concentrated salt solution - brine - remains in the lake.
The entire surface of the salt marsh is covered with "kalich", a porous rock of gypsum and halite impregnated with brine. The depth of such "kalich" can reach several tens of meters.
The main compounds in brine are lithium chloride and sulfate. And the total proportion of metal in one liter of such a cocktail can reach 7 grams per liter. According to this parameter, the Chilean salt marsh (Salar de Atacama) is simply unmatched in the world.
In addition to lithium salts, compounds of sodium, potassium, bromine and calcium are dissolved in the brine. Magnesium compounds are almost always adjacent to lithium in brines. If the ratio of magnesium to lithium is greater than 11/1, mining may not be economically viable.
Lithium deposit in Bolivia. Source: dw.com
Now a little about the United States' lithium program.
The metal is mined on brine in the state of Nevada. Fortunately, the climate favors the Americans for this. The US Geological Survey does not publish open data on production volumes. But indirect sources say that most of the lithium raw materials (up to 84%) the country imports from Latin America. More than 35% of the volume of domestic production and import of lithium goes to the production of batteries. And every year this share only increases.
Russia in lithium stories clearly not among the leaders. The climate does not allow for the evaporation of minerals from salt lakes in the sun. And domestic consumption is not particularly developed. And it is unprofitable to sell lithium to foreign markets - Latin American mining giants are asking much less for the strategic metal. Nevertheless, lithium reserves in Russia are estimated at 900 thousand tons, most of which are concentrated in groundwater.
"Lithium triangle"
An even larger deposit of "dissolved in water" lithium is the high-altitude salt marsh Salar de Uyuni in Bolivia, which, according to various estimates, has preserved up to 100 million tons of metal.
Despite such impressive reserves, it is expensive to extract lithium from the Salar de Uyuni salt marsh, as the ratio of Mg to Li reaches 18,6. For comparison: in the Salar de Atacama salt marsh, the same indicator is close to 6,4.
Together with Argentina, Bolivia and Chile make up the so-called "lithium triangle" of Latin America, which controls up to 70% of the world's lightest metal market.
One can often see the following picture at deposits: powerful pumps pump brine to the surface of salt marshes from the depths of the earth, which in a year and a half in the sun turns into brine. The landscape is mesmerizing - geometrically correct artificial reservoirs, each of which is the size of several football fields, go far beyond the horizon. It takes a lot of energy to fill these tanks.
For example, in the Salar de Atacama salt marsh, mining companies raise up to 2 liters of deep brine per minute to the surface in this way. This seriously accelerates the process of mining lithium salts, but negatively affects the ecological state of the surrounding area. Due to the constant pumping of groundwater and intense evaporation, the supply of fresh water in the area around is decreasing. As a result, residents complain about the lack of fresh water and the massive death of fish in drained water bodies.
The places where lithium was mined in Latin America even received a peculiar name - "white death". The ever-growing demand of the global industry for lithium and the environmental damage associated with mining makes one think about the reality of the "green" status of civilian lithium-ion batteries.
Lithium from stone
It is relatively easy to extract lithium salts from concentrated brine, when the sun and dry climate do some of the work. But what if nature has deprived the area of lithium salt marshes?
You can search in unconventional sources. For example, in associated oil waters or geothermal brines. But the concentration of lithium compounds in them is low - in oil waters the proportion of lithium chloride LiCl is not more than 1 g / l.
Therefore, it is much more profitable to look for metal in the composition of rocks.
Currently, solid minerals hide up to 23% of the world's lithium reserves. Of course, it is difficult and expensive to extract valuable metal from such raw materials. But the high demand for batteries covers all costs. The key minerals of industrial importance are various granites: spodumene, lepidolite, amblygonite and petalite.
The main proven reserves of lithium minerals are located in the United States, China, Australia and Canada. Recently, spodumene deposits were discovered in Portugal, in which the proportion of lithium oxide can reach 5%.
Relatively small deposits of lithium minerals have been found in Russia, Finland, Portugal, and some African countries.
The USA and China are unique in this regard - they are the only countries with granite deposits and saline lithium lakes.
Do not forget about the recycling of failed lithium-ion batteries. One of the first to use a complex recycling procedure at the plant of the American company Rockwood Lithium in 1992 in Canada. The company is now the world leader in the recycling of lithium ion batteries. And the development potential will allow in the future to recycle most of the batteries.
However, now the world's reserves of lithium are so large and widely available that it is much easier to remove the metal from nature than to spend money on laborious extraction from old batteries. According to analysts, if by 2030 the demand for lithium reaches the planned 28 tons per year, then the development of an efficient method of recycling batteries will come to the fore.
From raw materials to semi-finished products
Before lithium becomes part of a storage battery, it must undergo an extraction and enrichment procedure.
First of all, lithium chloride from lake brine must be precipitated in some way in an insoluble form. For this, ammonium bicarbonate is excellent, which allows to isolate up to 99,8% of lithium from brine in the form of carbonate.
And if the concentration of lithium compounds is too low, and chemical precipitation of salts is unprofitable?
For this, technologists have developed methods of selective absorption of compounds dissolved in water by solids - selective sorption. Special ion-exchange resins "taught" to sorb only Li ions+leaving Na ions in solution+ and other active metals.
After primary processing of lithium raw materials, chloride is again obtained from poorly soluble lithium carbonate. The next step is the electrolytic separation of the pure metal. Electrolysis is carried out in a molten salt, pre-adding potassium and barium chlorides to lower the melting point of the electrolysis mixture. The final purification of lithium is carried out by distillation under vacuum conditions in order to exclude contact of the active metal with air components, and at a temperature of about 550 ºС.
Lithium carbonate is the main form for export and import of the world's lightest metal. Source: dw.com
Hard granite lithium-containing minerals are much more difficult to enrich and process. After mechanical crushing of the rock, flotation enrichment of the rock occurs - this is the most common method for the primary processing of solid lithium minerals. For this purpose, particles of rock are moistened with special oils, which are released in the flotation baths as part of the foam. Spodumene minerals are enriched by high temperatures. In the course of such sintering, the mineral particles crack and crumble into powder, which is separated from the gangue minerals by screening or air separation.
Further, the lithium concentrate is transferred to the hands of process chemists. Processing is carried out using lime, sulfate or sulfuric acid methods. For this, calcium carbonate, potassium sulfate and sulfuric acid are used. The output is lithium sulfates and carbonates, which are processed, converting the compounds into lithium chloride.
Lithium comes to consumers in various compounds. Most of all (up to 40% of world sales) falls on lithium carbonate, the second place is taken by liquid lithium concentrate (22%), lithium hydroxide (16%) and lithium chloride (4%). Pure lithium metal accounts for 4% of world sales, the remaining 12% is occupied by multicomponent lithium compounds.
Not just batteries
Lithium in the 70st century is not only a raw material for modern storage batteries. Despite the fact that up to XNUMX% of the world's lightest metal production is spent on the needs of the electric power industry, lithium has found wide application in other industries.
When lithium compounds are added to glass, products made from it become chemically resistant, transmit ultraviolet and infrared radiation - an important property in military affairs. If lithium salts are included in the recipe for making ceramics, then you get high-voltage and high-temperature porcelain.
Lithium salts of fatty acids have found application in lubricants for thickening petroleum oils. For example, lithium stearate is used in the well-known lithol.
Without lithium compounds, a person would hardly have been able to master the depths of the sea and outer space. It's all about lithium peroxide, which is used in systems for cleaning air from carbon dioxide on submarines and manned spacecraft. The reaction takes place with the release of oxygen and the absorption of carbon dioxide.
In nuclear power, lithium is used as a coolant for cooling reactors, and lithium hydride LiH is very promising as a hydrogen storage substance.
Lithium, as a key component of traction batteries for electric vehicles, has already established itself as the “new gasoline” of the 4st century. But scientists are seriously considering lithium as a rocket fuel. It turns out that when lithium hydride, lithium boride LiB and pure metal are burned, up to 000 kcal of energy are released, while ordinary kerosene produces only 2 kcal. Due to the high proportion of oxygen (up to 300%), lithium perchlorates and nitrates can be excellent oxidizers of rocket fuel. For comparison, the classical oxidant ammonium perchlorate contains only 69,5% oxygen.
The prospects for lithium in the power industry are rather unpredictable. On the one hand, the reserves of lithium compounds dissolved in brines will be enough for mankind for no more than 50 years (in solid rocks - for 25 years), and on the other hand, valuable minerals are unlimitedly dissolved in small concentrations in almost all groundwater.
Only now it is completely unprofitable to extract lithium from such water.
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