As of 2021, Bikita is the only mine in South Africa Zimbabwe producing lithium, and currently that lithium is not used in battery supply chains. However, the Bikita mine area does contain spodumene pegmatites, which may contribute to the battery supply chain in the future.
Spodumene origin include California, Minas Gerais, Madagascar, Pakistan, Myanmar, Xinjiang, China, etc.
How is lithium harvested and processed?
Lithium carbonate, as the basic lithium salt of lithium, is an additive and cosolvent used in glass manufacturing and ceramic production. The production process of lithium carbonate is different due to different raw materials. What are the production processes of high-purity lithium carbonate?
As a light metal, lithium is widely used in industrial production because of its high toughness, good ductility and good chemical activity. At present, the types of lithium ores used in the industrial field include spodumene, lepidolite, spodumene, lepidolite, lepidolite and diorite feldspar. Because of different types, their beneficiation processes are also different.
High purity lithium carbonate is generally produced by deep carbonization, impurity removal and thermal decomposition of industrial grade lithium carbonate or battery grade lithium carbonate.
In the production of lithium carbonate with spodumene as raw material, the industrial mature process is sulfuric acid process. The basic principle of this process is that sulfuric acid and spodumene undergo displacement reaction at 250~300 ℃ to generate lithium sulfate.
This reaction can only occur in spodumene with relatively loose structure. After fine grinding of lithium ore with Vertical Mill，spodumene concentrate obtained from beneficiation is calcined in a rotary kiln at high temperature. After cooling, it is mixed with sufficient sulfuric acid and sent to a 250 ℃ acidification rotary furnace for sulfuric acid roasting. After cooling, soak in water, add limestone to control the PH value to obtain crude lithium liquid containing about 10%, adjust the PH to 11 with lime, and add sodium carbonate to remove impurities such as calcium, magnesium, iron and aluminum. The purified lithium sulfate solution containing about 20% is weighed by evaporation of the clear solution, and sodium carbonate is added to precipitate into lithium carbonate. The lithium carbonate product is obtained by centrifugal dehydration with a recovery rate of about 90%.
The yield of lithium carbonate produced by sulfuric acid method is high. Spodumene and sulfate are mixed and sintered at a certain temperature. After a series of physical and chemical reactions, the metal elements in the sulfate added will replace lithium in the ore to generate soluble sulfate, and the main impurities will generate compounds that are difficult to dissolve in water. Then the sintered clinker will be leached and separated, and lithium ions will enter the solution for purification, concentration The lithium carbonate product is obtained after precipitation.