1

Four Lithium Extraction Technologies

 

Currently, there are four lithium extraction technologies: spodumene lithium extraction, mica lithium extraction, clay lithium extraction, and brine lithium extraction. The first three have been industrialized, while clay lithium extraction is expected to be industrialized by 2023-2024.

 

2

Salt Lake Lithium Extraction Technology Route

 

Salt lake lithium extraction uses completely different process routes depending on the brine. Taking China's salt lakes as an example, the technological routes used in Qinghai and Tibet salt lakes are different. Foreign salt lakes also use different methods due to varying lithium content:

 

(1) Solar Evaporation Method Countries like Chile use more traditional methods because their brine has high lithium content and low magnesium impurities, making extraction simple. Therefore, they use the classic solar evaporation method. The Zabuye Salt Lake in Tibet also uses this method;

 

(2) Adsorption Method The adsorption method has gradually matured and been industrialized, especially advantageous when the magnesium-lithium ratio is high. The Salar de Charcas, with a magnesium-lithium ratio exceeding 100:1, is suitable for this method. Lanke Lithium Industry in Qinghai also uses this method, and after China Baowu's recent entry into Zabuye in Tibet, they also plan to switch to the adsorption method;

 

(3) Electrodialysis Method Mainly used in the Dongtai Salt Lake;

 

(4) Membrane Method Used in the Xitai Salt Lake;

 

(5) Solvent Extraction Method More commonly used by Dahua.

 

These technological routes have all been industrialized in China. In the future, with continuous technological advancements, the adsorption method will become more competitive due to its advantages in higher yield, more efficient adsorbents, faster kinetics, lower costs, and high lithium extraction rates. This is the main focus of future research.

3

Comparison of Four Lithium Extraction Methods

 

There is no difference in the lithium salts produced by different lithium extraction methods. The impurities in lithium salts from ore and brine extraction differ slightly. For example, ore lithium extraction, such as that by Ganfeng Lithium, has high sulfate indicators, while brine lithium extraction has high halide indicators.

 

However, the quality can be made consistent through processing and purification. For example, lithium carbonate can be purified through deep carbonization, and lithium hydroxide quality can be improved by increasing the recrystallization process and cost. The extraction method does not affect the quality of lithium.

 

(1) Ore Lithium Extraction The ore method is currently quite mature. Previously, Xinjiang Salt Works used limestone, but the 1:3 limestone ratio in the calcination process resulted in lower overall yield. The current mainstream method is the sulfuric acid method. The main cost of ore lithium extraction lies in the procurement of raw materials; the direct processing cost is actually lower than that of brine extraction.

 

(2) Brine Lithium Extraction The overall cost of brine extraction is lower because the brine is self-owned, unlike ore which is procured upstream. However, the processing cost is higher, so the processing cost is essentially the total cost. Producing high-quality products by adding a process step is not a problem; many domestic companies can achieve this.

 

(3) Mica Lithium Extraction Mica lithium extraction is a technology used by Jiangxi Salt Works. Previously, with a lithium mica grade of 4.4-4.5%, the limestone method could be used, with calcination using a 1:3 limestone ratio.

 

Now, with lower ore grades (around 2.2% lithium mica), the limestone method is unsuitable, and the sulfate method is commonly used, involving the calcination of lithium mica + sodium sulfate + calcium sulfate + a small amount of potassium sulfate. This method is currently performing well.

 

4) Clay Lithium Extraction Currently not yet industrialized. There are three main methods: sulfuric acid method (higher impurity content and greater environmental impact), sulfate method (similar to mica lithium extraction, with a lithium leaching rate of around 95%), and autoclave method (higher yield but higher cost).

 

4

What are the difficulties in expanding production of salt lake and mica lithium extraction in China?

 

(1) Salt Lake Lithium Extraction Globally, foreign salt lakes are of better quality, especially in Chile, with lithium content exceeding 1000 mg/L and a magnesium-lithium ratio of 1:3. In China, the brine grade is lower, with lithium content in the original brine ranging from 30-50 mg/L. This leads to high costs for investment expansion; building a 10,000-ton facility might require 500-800 million yuan.

 

The low concentration and grade of China's salt lakes limit expansion, restricting the amount of usable brine and making it difficult to achieve large-scale production.

 

However, China's lithium extraction technology is very advanced, with various methods such as adsorption, membrane, electrodialysis, and solvent extraction being among the most advanced in the world. Other countries need to learn from China. If Chinese companies build factories in foreign salt lakes, the overall construction cost is generally higher. For example, in Argentina, construction sites use equipment, even photovoltaic power generation equipment, purchased from China and shipped to Argentina. However, resources such as natural gas are cheaper than in China. Other costs are difficult to compare. If auxiliary materials are purchased domestically, it will increase freight and customs clearance costs, potentially increasing the overall cost.

 

(2) Mica Lithium Extraction Domestic mica ore has relatively low grades, with very few exceeding 0.8%. If the standard is lowered to 0.3% or 0.4%, although more ore is available, the yield is lower. Some use 2.2% lithium oxide ore to produce lithium carbonate and lithium hydroxide, so mica lithium extraction output is limited by ore grade.

 

With 0.4% grade ore, 8 tons of raw ore produces 1 ton of concentrate, and 25 tons of concentrate produces 1 ton of lithium carbonate. Therefore, a total of 200 tons of concentrate is needed to produce one ton of lithium carbonate. Clearly, lower grades lead to greater production difficulties.

 

 

5

Environmental Impact on Lithium Extraction Methods

 

The implementation of ESG will have a significant impact on the industry. China has also set targets for carbon peaking and carbon neutrality.

 

This necessitates adjustments to lithium extraction methods, focusing on energy efficiency and reduced water consumption. For example, Ganfeng has a water recycling project aiming to recover over 1 million tons of water.

 

Simultaneously, there's an emphasis on energy conservation and environmental protection, such as using photovoltaic power instead of thermal power. Let's examine three lithium extraction methods:

 

(1) Salt Lake Lithium Extraction Currently, there are some limitations, but the impact is relatively minor. Salt pan construction already considers the comprehensive utilization of elements in brine. For instance, in Chilean brine development, potassium is extracted before lithium. Methods like adsorption involve discharging the adsorbent into the salt pan, without adding organic matter or other impurities. Therefore, there's no environmental impact from this perspective.

 

(2) Mica Lithium Extraction This method is significantly impacted because mica contains fluorine, requiring reinforced fluorine processing to prevent environmental pollution from fluorine release. Furthermore, since current mica lithium extraction uses the sulfuric acid method, the waste residue contains sodium, potassium, and calcium, which is detrimental to the cement industry that uses this residue. The increasing amount of waste residue exceeds the cement industry's processing capacity, leaving remaining slag requiring further treatment.

 

(3) Lithium extraction from ore The waste residue contains less impurities compared to mica lithium extraction, mainly hydrogen. However, there are impacts on energy consumption (natural gas and coal gas), exhaust emissions, and water discharge.

 

6

Persistent Shortage of Lithium Resources

 

Demand Side Judging from the expansion rate of cathode materials, especially lithium iron phosphate, in the latter half of this year, the demand for lithium salts is increasing, and the supply shortage will continue, possibly until 2030. The current situation is highly favorable for lithium salt development, and prices are expected to remain in the range of 100,000-120,000 yuan/ton.

 

Supply Side International companies like Australia's Galaxy, Talison, and Pilbara can provide stable supplies, and they may gradually increase production capacity in the next 2-3 years. Meanwhile, countries in Africa like Mali, the Democratic Republic of Congo, and Brazil are also expected to start supplying spodumene in 2023. The DRC's AVZ has particularly large reserves, exceeding 200 million tons of raw ore. Overall lithium supply will increase in the future, but it will still be difficult to balance supply and demand.

 

7

Impact of Solid-State Batteries and Sodium-Ion Batteries on Lithium

 

Solid-State Batteries The development of solid-state batteries has a positive impact on lithium resources. The commercialization of pure solid-state batteries still has a long way to go, possibly until 2028-2030. However, hybrid solid-state batteries can improve battery performance by increasing energy density and enhancing safety through the use of metallic lithium and reduced electrolyte.

 

Since the anode of hybrid solid-state batteries uses metallic lithium, and the cathode remains largely unchanged, and the electrolyte uses solid electrolytes, which are generally oxide or sulfide solid electrolytes, the lithium content will be higher.

 

Sodium-Ion Batteries The development of sodium-ion batteries has a certain degree of inhibitory effect on lithium demand. However, overall, sodium-ion batteries are not suitable for all application scenarios. They can be used in energy storage or two-wheeled vehicles, but they have limitations in many other areas, such as mobile phones, where the user experience may decline if charging is required every half-day instead of once a day.

 

Furthermore, large-scale promotion of sodium-ion batteries is needed to reduce costs. Considering the overall system cost, for example, in lithium-ion battery systems, battery costs only account for 60%, while the remaining 40% is management system costs. Due to the lower energy density of sodium-ion batteries, higher management costs are required, so the total cost remains high.

 

8

Bottleneck in Battery Recycling Lies in Dismantling

 

With rising prices, the recycling value of both lithium iron phosphate batteries and ternary batteries has increased significantly. The biggest current limitation is dismantling. Battery recycling mainly involves two methods:

 

(1) Pyrometallurgy This involves burning waste batteries in a furnace to produce iron ingots, and then recovering metals through acid melting. However, this method makes lithium recovery difficult because it volatilizes during the burning process. Companies like Umicore in Belgium mainly use this method.

 

(2) Dismantling Method This is the mainstream method in China. After dismantling waste batteries and removing the shell, the battery cells are burned in a kiln and then ground to separate copper and aluminum. Nickel, cobalt, and lithium are recovered from the cathode material through acid dissolution.