Lithium is the lightest element of all metals. It is widely used in air
treatment, batteries, ceramics, glass, metallurgy, pharmaceuticals and polymers.
Rechargeable lithium-ion batteries are particularly important in addressing
global warming because they can use renewable energy sources (such as
hydropower, solar or wind) to power cars and trucks, rather than burning fossil
fuels.
Nowadays, lithium is generally extracted from salt water extracted
under arid sedimentary basins, or from granite pegmatite ores. The main producer
of lithium in brine is Chile, and the main producer of pegmatite lithium is
Australia. Other potential sources of lithium include clay, geothermal brine,
oilfield brine and zeolite.
When the cooled magma starts to crystallize minerals, lithium will remain in
the remaining melt until the end. The active plate tectonics in the earth's
history concentrated lithium in the continental crust through partial melting of
the mantle under the mid ocean ridge and volcanic arc. Melt or magma rises and
then cools to become a new rock in the crust, bringing a large amount of
available lithium.
Among the common rock or sediment types, shale (66 ppm on
average), deep-sea clay (57 ppm on average) and low calcium granite (40 ppm on
average) have high lithium concentration. These trace concentrations are not
enough to form ore deposits, or even minerals where lithium is part of the
chemical formula. When only such trace concentrations exist, lithium atoms will
replace other metals (usually magnesium) in common rock forming minerals. Only
when favorable factors are arranged in rare combinations can lithium minerals be
formed.
Most of the known lithium minerals exist in coarse grained granites
called lithium cesium tantalum (LCT) pegmatites. In terms of lithium resources,
the important minerals are spodumene and diopside feldspar (both aluminum
lithium silicate) and mica lepidolite (potassium lithium aluminum silicate). The
main lithium mineral in sedimentary rocks is clay lithium montmorillonite.
Lithium is very soluble. In the weathering process of rocks, they are often
removed in solution and carried to the sea by rivers. Therefore, lithium is
expected to accumulate in the ocean, just as sodium accumulates to make the
ocean salty. However, it is worth noting that the lithium content in seawater is
less than 1 ppm. The reason may be that lithium in sea water is slightly removed
by clay minerals and accumulated in the seabed ooze.
Lithium deposits can be roughly divided into six categories: lithium cesium
tantalum pegmatite deposits, lithium rich granites, lithium salt deposits in
closed basins, lithium, lithium clay deposits in other saline waters, and
lithium zeolite deposits.
Lithium cesium tantalum pegmatites are found in the hinterland of metamorphic igneous rocks in the orogenic belt, which is the result of plate convergence. Most of the lithium cesium tantalum pegmatites were formed during the collision between continents or microcontinents, and were related to the aluminum rich granites produced by the melting of metasedimentary rocks. Dozens of pegmatites in the Appalachian Mountains were formed in the long-term collision between Africa and North America 370 million to 275 million years ago. Lithium cesium tantalum pegmatites can be dated using isotopic chronology. In pegmatites, the decay of uranium 238 to lead 206 is used to determine the age of niobium tantalite and zircon. The age of lithium cesium tantalum pegmatites from six continents has been determined.
Some muscovite bearing granites include areas rich in lithium, tantalum, tin
and fluorine. In Yichun Mine, Jiangxi Province, China, the top of biotite
muscovite granite is graded as muscovite granite, and then turned into lithium
mica granite. Lithium and tantalum have been mined. Lithium rich granite is
closely related to LCT pegmatite, and in the recent global lithium resource
assessment, the two are not distinguished from each other.
The closed basin brine deposits are estimated to account for 58% of the
world's proven lithium resources. Lithium brine sediment is the accumulation of
saline groundwater rich in dissolved lithium. The average lithium concentration
of the lithium ore deposit under production ranges from 160 to 1400 ppm, and the
estimated lithium resource is 0.3 to 6.3 million tons. Lithium deposits in
production are located in Asia, North America and South America, in the north of
both sides of the equator and in the arid latitude zone. These deposits have
many common features:
(a) Arid climate;
(b) A closed basin containing salt
lakes or salt flats;
(c) Tectonic driven subsidence;
(d) Related igneous
rock or geothermal activity;
(e) Lithium bearing source rock;
(f) One or
more sufficient aquifers to contain brine reservoirs;
(g) There is enough
time to concentrate brine.
Deep oilfield brine may contain up to several hundred parts per million of
lithium. In some places, the lithium content in brine is as high as 692 mg/L
(mg/L). Brine occupies the pore space of limestone with a thickness of about 200
meters at a depth of 1800 to 4800 meters. Saltwater, known as trapped seawater,
subsequently enriched lithium and other trace elements by hydrothermal means. As
a potential lithium resource, oilfield brine has two disadvantages. First, they
usually occur at a deeper depth (greater than 1 km) than saline water in closed
basins. Second, unless they happen to be located in an arid climate, it will not
be feasible to recover lithium using convenient and cheap solar evaporation
methods. Geothermal saline water is another potential source of lithium. These
fluids traditionally derive their value from the heat they contain, which can be
converted into mechanical energy - but some geothermal fluids contain abnormally
dissolved metals, including lithium. It is reported that Simbol, Inc. is now
recovering lithium from geothermal brine in the Salton Sea area along the
California Mexico border.
A small part of the world's clay deposits are rich in lithium. Lithium
bearing clay deposits account for about 7% of the world's lithium resources.
Lithium clay exists in hydrothermal altered sediments of lakes in volcanic
craters. The method of recovering lithium by leaching clay with sulfuric acid
has been proved to be feasible. In Türkiye, the world-class Bigadi ? borate
deposit was formed in hydrothermal altered sediments filled with rift related
lake basins, containing related lithium montmorillonite.
The only lithium zeolite deposit recorded comes from the Neogene basin system
in the Balkan region of Eastern Europe. The Miocene lake bed of the Jadar basin
includes oil shale, carbonate rock, evaporite and tuff. These strata are
authigenic with a large number of jdarite layers, which are recently recognized
as boron lithium silicate minerals of zeolite family. It is reported that the
jadeite rock layer is several meters thick. This single jadeite deposit is
estimated to account for 3% of the world's lithium resources.
The above are
six types of common lithium ores. At present, lithium ores used to extract
lithium and make lithium carbonate include salt lake lithium, lepidolite,
spodumene, etc. Xinhai Mineral Equipment Co., Ltd. is specialized in lithium ore
purification process and equipment. Please consult us if necessary.
