How to extract lithium carbonate from salt lake brine, what are the methods?
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2023/03/14 10:20:59
In the global lithium resources, salt lake type lithium deposits are very important, accounting for about 60% of the global lithium resources. Compared with the preparation of lithium carbonate from spodumene, the preparation of lithium carbonate from salt lake brine not only has a higher content of lithium, but also has abundant resources, low energy consumption and low product price, so it has become the main research direction for domestic and foreign companies to develop and produce lithium salt. When it comes to extracting lithium from brine, there are two definitions
First, there is "brine," liquid salt water with a salt content greater than 5 percent.
The second is "salt lake", which refers to lakes with high salinity in arid areas.
We usually say that brined tofu, is to use such salt lake refined coarse salt, brine configuration, so that soy protein solidified, from soy milk into tofu.
How did these beautiful salt lakes form?
The evolution of salt lake is closely related to tectonic movement, regional climate and environmental changes. Strong tectonic movements formed mountains and rifts, and basins were formed in the relatively low-lying areas of these mountains and rifts. The surrounding mineral-rich water flowed into low-lying areas and lakes were formed. As the regional climate gradually became arid, rainfall decreased and sunlight became sufficient, fresh water evaporated and lake water became salty, forming brine deposits.
Based on the above special geographical conditions, salt lake type lithium deposits are mainly developed in arid and windy closed basins, so the distribution of resources is extremely unbalanced. The salt lake type lithium deposits are densely distributed in arid areas near the equator -- 30-40° north latitude and 20-30° south latitude. The global salt lake lithium resources are mainly distributed in the Andes Mountains of South America and the Tibetan Plateau of China.
In 2021, the output of South America's salt lakes accounts for 67% of the global output, while China's salt lakes account for 31%. It can be seen that China's dependence on foreign sources of new energy is relatively high. As a resource-based product, "lithium", the domestic autonomous and controllable salt lake resources are of great strategic significance for the healthy development of our new energy industry.
China's salt lakes are mainly Qarhan, Dongtai Kiner, Xitai Kiner, Yiliping Salt Lake in Qinghai, and Zabuye Salt Lake in Tibet.
According to the different concentration, magnesium lithium ratio is different, different salt lake extraction method of lithium carbonate is different
High concentration and low magnesium ratio salt lake lithium extraction general use, precipitation method: such as South America's high quality high concentration salt lake; Solar pool method: The Zabye Salt Lake in Tibet is a representative of the high concentration of lithium carbonate salt lake.
Extracting lithium from brine with low concentration and high magnesium-lithium ratio generally uses extraction method, calcination method, adsorption method, and membrane method, etc., which is usually used in combination with a variety of methods.
For example, due to the low concentration of lithium in Qarhan Salt Lake, it is necessary to increase the concentration of lithium in the brine by adsorption method before using the film method. Zangge Lithium and Lanke Lithium, which is affiliated to Yanhu Company, use the adsorption + film method, with the front-end process being adsorption and the back-end process being film method. East Taiwan, west Taiwan, one Li Ping, etc., using the membrane combination; A combination of electrodialysis and nanofiltration membranes was used in Dongtai and Yiliping. Qinghai Daqaidan Salt Lake, the representative company for Dahua Chemical industry and Jintai Lithium is the extraction method.
It can be seen from the above that the rapid development of new energy in China, the demand for lithium resources, and the low grade brine concentration force the progress of lithium extraction technology in China's salt lake. Currently, our lithium extraction technology in salt lake has been leading the world.
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