Lithium ore mainly includes spodumene (containing Li2O5.8% ~ 8.1%), lepidolite (containing Li2O3.2% ~ 6.45%), lithium spodumene (containing Li2O7.1% ~ 10.1%), lithium feldspar (containing Li2O2.9%~4.8%) and iron lithium mica (containing Li2O1.1%~5%), among which the first three minerals are the most important.
At present, the lithium carbonate produced in the market is mainly spodumene, followed by lepidolite and petalite, which are more suitable for the production of glass ceramics, because although the lithium content is low, there are few impurities. Phosphopersite, also known as hectorite, has a high lithium content, but the element phosphorus in the raw ore cannot be separated, so it is not suitable for lithium carbonate, so its utilization value is low.
Spodumene is a kind of pyroxene, which is mostly produced in granite pegmatite, and sometimes can form coarse crystals. Spodumene is a high-quality mineral source for industrial extraction of lithium. Spodumene is a silicate mineral with a chain structure, and its color is mostly off-white, green, dark green or yellow, with glass luster, translucent to opaque. The chemical composition of spodumene is LiAl[Si2O6], in which the theoretical content of Li2O is as high as 8.03%. The spodumene concentrate generally contains 6.3~7.5% Li2O, and the actual content is usually in the range of 2.91~7.66%.
Lepidolite is a common lithium mineral and an important mineral for extracting lithium. It is a basic aluminosilicate of potassium and lithium, which is one of the mica minerals. Lepidolite is generally only produced in granite pegmatites. The color is purple and pink and can be light to colorless. It has a pearly luster and is in the form of short columns, small flake aggregates or large plate-shaped crystals. The main component of lepidolite is KLi1.5Al1.5〔AlSi3O10〕(F, OH)2, containing 1.23-5.90% Li2O, and often containing rubidium and cesium.
Because the content of Li2O in spodumene is relatively high, and the cost of extracting lithium is lower, it is currently the main mineral used to extract lithium metal. However, with the continuous optimization of lepidolite lithium extraction technology, the cost of lithium extraction has been continuously reduced, and the recovery rate has gradually increased. At present, lepidolite has become an important mineral for lithium extraction after spodumene.
Although both spodumene and lepidolite are important minerals for lithium extraction and further preparation of lithium carbonate, their beneficiation methods are not consistent due to the large difference in mineral composition between the two.
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