How is Spodumene Processed into Lithium Concentrate?

With the global energy structure gradually transitioning to a low-carbon model, lithium resources—often referred to as "white oil"—play a critical role in this transformation.

Lithium is especially vital in the development of electric vehicles (EVs), energy storage systems, and 3C (computer, communication, and consumer electronics) products, making it a core raw material for the new energy industry.

Among lithium-bearing minerals, spodumene has become a key source for producing lithium concentrate due to its high lithium content and large-scale deposits. However, spodumene must first be processed through mineral beneficiation before entering the smelting stage.

So, how is spodumene processed into lithium concentrate? This article provides a detailed explanation of the spodumene beneficiation process.

01Spodumene Classification

1. α-Spodumene and β-Spodumene

Spodumene exists in two phases: α-spodumene and β-spodumene.

α-spodumene is monoclinic, dense, stable, and chemically inert, making it difficult to react with acids or bases. Its direct acid leaching rate is extremely low. Therefore, the crystal structure must be destroyed by high-temperature calcination, converting it into the β phase.

β-spodumene is hexagonal in structure, with a loose and porous lattice and significantly higher reactivity. The leaching rate using the sulfuric acid method can exceed 90%. Additionally, thermal conversion to β-spodumene reduces hardness, thereby decreasing grinding energy consumption by approximately 40%.

2. High-Grade and Low-Grade Spodumene

Spodumene with Li₂O ≥ 1.5% is classified as high-grade, while spodumene with Li₂O < 1.0% is considered low-grade.

High-grade spodumene has a simple mineral composition, and its boundary with gangue minerals is well-defined. A small amount of collector is sufficient to produce a concentrate that meets grade requirements.

The main challenge in processing high-grade spodumene lies in the tendency to produce fine particles during the fine grinding stage, which can interfere with flotation performance.

If the ore contains a significant amount of iron-bearing minerals, a magnetic separation step is necessary, which increases the complexity of the flowsheet.

Low-grade spodumene is finely disseminated and exhibits strong similarities with gangue minerals, making it difficult to separate. Therefore, multiple stages of desliming and concentration are required before the concentrate grade meets the required standard.

02Spodumene to Lithium Concentrate Processing

1. Ore Pretreatment

Crushing and Screening: The spodumene ore is first crushed by a jaw crusher, followed by medium and fine crushing using a cone crusher. The crushed material is then screened using a vibrating screen. Oversized material is returned to the cone crusher for re-crushing, while undersized material proceeds to the grinding and classification stage.

Grinding and Classification: The screened spodumene is fed into a ball mill for grinding and subsequently classified by a hydrocyclone. The fine slurry flows directly to the flotation stage, while the coarse particles are returned to the ball mill for further grinding.

2. Beneficiation Process

Flotation (Mainstream Process): Flotation is the primary method used to separate spodumene from gangue minerals. Prior to flotation, desliming is conducted to remove fine mud. Then, pH regulators and collectors are added. In the flotation cell, spodumene attaches to air bubbles and rises to the surface under agitation and aeration. The resulting froth is collected as lithium concentrate.

Reagent System: Common pH regulators include sodium hydroxide and sodium carbonate. Collectors typically include oleic acid (a fatty acid) or cationic oxidized paraffin soap. Gangue minerals are suppressed using depressants such as starch or dextrin.

Flotation Flow: The flotation circuit typically includes roughing → scavenging → cleaning, with multi-stage flotation employed to maximize recovery.

Gravity and Magnetic Separation (Auxiliary Processes): If the ore contains a significant amount of fine-grained iron minerals, magnetic separation is applied before flotation to remove iron impurities and prevent interference in downstream flotation. If the gangue minerals contain heavy impurities such as barite, a gravity separation stage may be introduced ahead of flotation to remove these heavy components.

3. Concentration and Dewatering

The flotation concentrate undergoes further thickening, dewatering, and drying. First, the lithium slurry is sent to a high-efficiency deep cone thickener, which increases the slurry concentration through flocculation and sedimentation.

The thickened slurry is then dewatered using a plate-and-frame filter press or a vacuum filter, reducing the moisture content to below 20%. Finally, the product is dried in a rotary kiln or similar drying equipment to produce finished lithium concentrate.

03Challenges in Spodumene Processing Technology

1. Flotation Reagents

Flotation is the core process in spodumene beneficiation. The performance of flotation reagents directly impacts the grade and recovery rate of lithium concentrate. However, current reagents face challenges such as poor adaptability to low-temperature environments and difficulty in effectively depressing gangue minerals. The application of composite low-temperature collectors, combined with nanoemulsion technology, can enhance reagent adsorption on mineral surfaces under low-temperature conditions, improving flotation efficiency.

2. β-Spodumene Activation Technology

Natural α-spodumene is highly inert and must be activated—typically through phase transformation—into β-spodumene to facilitate lithium extraction. Traditional high-temperature roasting methods have high energy consumption and operating costs. Emerging technologies such as microwave roasting and mechanochemical activation offer more energy-efficient alternatives to conventional roasting, reducing operational costs while improving conversion efficiency.

3. Comprehensive Utilization of Tailings

Spodumene ores are often associated with gangue minerals such as feldspar and quartz. The efficient utilization of tailings and comprehensive recovery of valuable by-products have become key industry concerns. For instance, a spodumene tailings project in Xinjiang adopts a combined magnetic separation–flotation process to recover feldspar and quartz, resulting in an annual output value increase of over 120 million yuan.

The above outlines the processing flow for converting spodumene into lithium concentrate, as well as recent technical advancements in overcoming processing challenges. Today, intelligent concentrator plants use AI-based dynamic optimization systems to improve lithium recovery rates, reduce reagent consumption, and enhance overall resource utilization.

Conclusion

Xinhai Mining offers full-process spodumene beneficiation EPCM+O services, helping clients to build intelligent, efficient, and sustainable concentrator plants. If you are interested, please feel free to contact us.