With the development of new energy vehicles, the demand for lithium resources at home and abroad is increasing day by day, which also causes the supply gap of lithium resources. About 35% of the world's lithium resources come from lithium-rich minerals and clay, so lithium can be extracted from lithium-rich minerals to meet the needs of the market. Its main beneficiation technology mainly includes three types, namely gravity separation, magnetic separation and flotation. Generally, gravity separation is mainly used to remove coarse gangue or to extract lithium from high-grade ores; Flotation is mainly used to purify fine-grained materials; Magnetic separation can be used to remove iron-bearing gangue from lithium-rich minerals and further improve the concentrate grade.
Because of the different types of lithium-rich ores, the beneficiation processes used are also different. The following will introduce three enrichment methods of spodumene, lepidolite and spodumene.
As an important raw material for lithium extraction, spodumene is mainly extracted by flotation and chemical leaching.
Spodumene flotation method: The flotation method has wide applicability and is widely used in spodumene purification with industrial value. However, flotation reagent is one of the important factors that affect the flotation effect of spodumene, so it can be replaced with high-efficiency and environment-friendly collector. For example, sodium oleate/tributyl 140000 phosphorous chloride can be used to separate spodumene from feldspar by flotation. It is a new type of mixed anion/cation collector, which can obtain better flotation separation effect. In addition, adding a small amount of cationic collector dodecylamine hydrochloride (DDA) during flotation can significantly improve the effect of anionic collector sodium oleate in separating spodumene from feldspar.
Spodumene chemical leaching method: one of the commonly used methods for spodumene purification during chemical leaching, but the ore needs to be pre-activated. Among them, the destruction of aluminum silicate structure is the key to lithium extraction by spodumene chemical leaching. Because spodumene is similar to illite, Bayer process can be introduced to treat natural lithium α- Spodumene is decomposed under alkaline conditions. Adding calcium oxide and increasing temperature can accelerate the decomposition of spodumene. After optimization, the leaching rate of lithium can be increased to about 93%.
Chemical leaching is one of the main methods for extracting lithium from lepidolite. Different leaching rates can be obtained by using different activator. For example, when potassium sulfate is used as an activator, the structure of lepidolite does not change significantly, and the leaching rate of lithium can reach 98.7%; If potassium salt is used as an activator, the leaching rate of lepidolite can reach 99.1% in combination with grinding. Therefore, it is necessary to select the appropriate type of activator and the quality ratio with concentrate. At the same time, the rotating speed of the ball mill, grinding time, reaction temperature and stirring speed are all factors that affect the effect of chemical leaching of lepidolite.
Lithium extraction from spodumite beneficiation generally refers to a mineral rich in lithium and phosphate, which first uses flotation method to obtain spodumite concentrate, then enters the mill for grinding pretreatment, and uses concentrated sulfuric acid for leaching, which can convert lithium and aluminum into soluble sulfate, extract fluoride and phosphate, and then obtain enriched leaching solution. Acid impurities can be precipitated by adding limestone, lime, monovalent carbonate or hydroxide to remove impurities in lithium-containing filtrate and recover lithium as lithium-containing salt product.
The above is a brief introduction of lithium extraction methods from spodumene, lepidolite and spodumite. Because the ore types and properties of different deposits are quite different, analysis is needed to determine the appropriate beneficiation process plan. Xinhai Mineral Equipment Co., Ltd. can provide you with lithium ore beneficiation process scheme design, complete lithium ore beneficiation equipment supply, on-site construction and installation of equipment, and project operation and management services in the later stage.
