Lithium is regarded as "the energy metal that promotes world progress". The industrial demand for lithium ore is increasing rapidly with the development of science and technology, electronic equipment, and new energy industries.
There are more than 145 lithium-containing minerals in nature, among which spodumene (containing Li2O 5.80%-8.10%) and lepidolite (containing Li2O 3.20%-6.45%) are the most common. This blog will introduce the method of extracting lithium concentrate from its ore.
Building an efficient lithium ore processing plant
Lithium, a valuable metal, is crucial in various applications, notably rechargeable batteries for electronics, electric vehicles, and energy storage. While lithium can be extracted from brine deposits, hard rock mining is another important source.
Chile and Australia are the largest reserves and producers, respectively, and both are primarily mining hard rock lithium ore. An effective hard rock lithium processing plant includes a crushing line, grinding line, beneficiation line, and drying line.
The most commonly used lithium mineral processing equipment include crushers (jaw crushers and cone crushers), vibrating screens, ball mills, flotation machines, magnetic separators, and dryers.
FTM Machinery can provide a series of lithium ore processing equipment, which is well-received in the world market. Our goal is to create more wealth for our customers. How to choose an efficient beneficiation method needs to be determined according to ore properties and actual needs.
Step 1 Conduct a mineral test
It is recommended to conduct a mineral test for lithium rock test before the separation and production.
According to the hardness of the ore, associated minerals, output, and investment budget, customize the most effective and scientific beneficiation process and equipment to avoid waste of resources.
Step 2 Crushing and grinding production line
First, the raw lithium ore undergoes a crushing and grinding process in sequence to produce a uniform fine particle size.
- When crushing, the jaw crusher is used for coarse (primary) crushing, and then the cone crusher is used for fine crushing.
- The crushed material is screened by a vibrating screen into a particle size below 15 mm. The unqualified materials will return to the cone crusher to continue crushing.
- Then, the material is wet-milled with a ball mill. Since the proper grinding fineness is crucial to the flotation effect, the particle size of lithium ore generally needs to be ground to less than 0.15 mm.
Step 3 Beneficiation production line
Many industries, especially the battery industry, require high-grade lithium concentrate. The removal of iron, magnesium, and other harmful minerals is key to these high-value markets.
To improve the lithium ore grade, a beneficiation process is required. Flotation separation is the main method for producing lithium concentrate, while other methods like magnetic separation play an auxiliary role. Learn about the beneficiation process for spodumene and lepidolite.
1. Flotation separation
Flotation separation is the main method of separating lithium ore at present. All lithium ore with industrial value can be enriched by flotation, especially the fine-grained disseminated lithium ore.
Flotation is done in an alkaline environment, as it not only has a good flotation result but also protects the flotation machine and is easy to control.
There are two flotation processes for lithium ore: positive flotation and reverse flotation. Lepidolite mostly uses positive flotation, while spodumene ore can be used for both positive and reverse flotation.
1.1 Lithium ore positive flotation method
Add strong alkali (such as sodium hydroxide or sodium carbonate) for flotation after the lithium ore is ground.
After high concentration, strong stirring, and multiple scrubbing in an alkaline medium, oleic acid and its soaps are added as collectors to float lithium concentrate, leaving gangue minerals in the tank. This process does not require inhibitors.
Note that when spodumene is used for positive flotation, sodium hydroxide is first added to the slurry for stirring and scrubbing to remove surface pollutants. After desliming and ore washing, it can be treated by any of the following methods:
- 1First float mica, then float spodumene and finally float feldspar.
- 2First float spodumene, then float mica and finally float feldspar.
- 3Do mix flotation of spodumene and mica and finally float feldspar to obtain spodumene concentrate.
1.2 Lithium ore reverse flotation method
Use lime to create an alkaline environment, and add regulators such as starch and dextrin to inhibit the lithium ore from floating.
At the same time, the amine cationic collector is used to float the silicate gangue minerals to the surface of the slurry, and the product in the flotation tank is lithium concentrate.
If the lithium ore contains iron minerals, foaming agents (such as HF, resinate, terpineol oil, etc.) can be added to further help remove impurities such as iron minerals. Finally, the lithium concentrate is obtained.
2. Magnetic separation
Lithium ore is often associated with complex components and the lithium concentrate obtained by flotation sometimes contains more iron. To improve lithium concentrate grade, the magnetic separation method is used as an auxiliary method.
The commonly used magnetic separators are vertical ring pulsating high gradient magnetic separator and wet magnetic separator.
For example, the spodumene concentrate produced by flotation separation in North Carolina, USA is high in iron. It can only be sold as a chemical-grade concentrate. To meet the requirements of the ceramic industry, the plant adopts magnetic separation to remove iron.
In addition, due to the weak magnetic properties of lepidolite, magnetic separation can be used as the main method to produce concentrate.
Step 4 Drying production line
The lithium concentrate after beatification usually contains high moisture content, so it needs to be dried to reduce the moisture content.
The FTM Machinery Rotary Drum Dryers are very popular in the drying market. It is wear-resistant, energy-saving, environmentally friendly, and has high drying efficiency. The drying temperature can reach 800°C and can reduce the water content of materials to below 8% or even 0.5% in a short time. The particle size is below 8 mm.
The dried lithium concentrate can be further refined into end products such as lithium batteries, electronic products, and potassium metal through the processes of calcination, chemical treatment, purification, and crystallization.
Conclusion
Most of the global lithium mines are located in southwestern South America and China. Due to the complex ore composition, plants often adopt the method of joint beneficiation to obtain high-grade lithium concentrate.
As one of the leading lithium processing companies, FTM Machinery is committed to providing optimal lithium processing solutions.
