At present, there are 4 kinds of lithium extraction technologies, namely spodumene extraction, mica extraction, clay extraction, and brine extraction. The first three of them have already been industrialized, and the lithium extraction from clay is expected to be industrialized by 2023-2024.
1. Technical route of lithium extraction from salt lake
Lithium extraction from salt lakes will use completely different process routes according to different brines. From the perspective of salt lakes in China, the technical routes used by Qinghai and Tibet salt lakes are different. Other countries will use different methods due to different lithium content.
- Spread drying method: Other countries such as Chile use a more traditional method, because its brine has high lithium content, less magnesium content, and simple extraction, so traditional and classic spread drying is used, and Zabuye Salt Lake in Tibet, China is also used. halogen method;
- Adsorption method: The adsorption method technology has gradually matured and realized industrialization, especially when the ratio of magnesium to lithium is relatively high. The Lanke Lithium Industry in Qinghai also uses the adsorption method. Recently, after China Baowu moved to Zabuye, Tibet, it also plans to switch to the adsorption method;
- Electrodialysis method: mainly used in Dongtai Salt Lake;
- Membrane method: used in Xitai Salt Lake;
- Extraction method: Dahua uses more.
2. Comparison of four lithium extraction methods
There is no difference between the lithium salts produced by different methods of lithium extraction. The extraction of lithium from ore and brine is only different in some impurity indicators. For example, the extraction of lithium from ore, such as Ganfeng Lithium Industry, has a high sulfuric acid index, and the extraction of lithium from brine has high halide ions. However, the quality can be achieved by adding process purification to achieve quality consistency.
For example, lithium carbonate is purified by deep carbonization. Lithium hydroxide can also improve product quality by increasing the recrystallization process and increasing the cost. Difference in quality will not be caused by differences in methods.
- Lithium extraction from ore: The ore method is relatively mature at present. In the past, the Xinjiang Lithium Salt Factory used limestone. The main cost of extracting lithium from ore lies in the procurement of raw materials, and the direct processing cost is actually lower than that of brine.
- Lithium extraction from brine: The overall cost of brine is still low, because brine is owned and ore is purchased upstream, but the processing cost is relatively high, so the processing cost is basically the full cost. And by adding a process, it is not a problem to make the product high-quality technology, and many Chinese companies can do it.
- Lithium extraction from mica: Lithium extraction from mica is the technology of Jiangxi Lithium Salt Factory. In the past, the grade of lepidolite was 4.4~4.5, which was relatively high, so the limestone method could be used to calcine it by 1:3 limestone.Now the ore grade has dropped, and the grade of lepidolite is about 2.2, so the limestone method is not suitable, and the sulfate method is generally used, lepidolite + sodium sulfate + calcium sulfate + a small amount of potassium sulfate for calcination, which is still relatively good at present.
- Lithium extraction from clay: it has not been industrialized yet. In principle, there are three methods, sulfuric acid method (higher impurity content and greater impact on the environment), sulfate method (similar to mica lithium extraction, the leaching rate of lithium 95%) and pressure cooking (higher yield but higher cost)
3. What is the difficulty of China's salt lake and mica lithium extraction and expansion?
Lithium extraction from salt lakes: From the perspective of the world, the quality of salt lakes in other countries is better, especially the salt lakes in Chile. The lithium content is more than 1,000 mg/L, and the ratio of magnesium to lithium is 1:3. In China, the grade of brine is relatively low, and the lithium content in the original brine is 30-50mg, which leads to the high cost of investment and expansion. It may cost 500-800 million to build a 10,000-ton plant.
Then, the concentration and grade of salt lakes in China are low, so that China's expansion will be more limited by resources, and it is difficult to make large-scale production due to the amount of effective brine. However, China's lithium extraction technology is very advanced. Various technical means such as adsorption method, membrane method, electrodialysis method and extraction method are the most advanced in China.
Other countries should learn from China. Moreover, if Chinese companies go to other countries to build factories in Salt Lake, the total construction cost in other countries is actually higher. For example, in Argentina, the site construction is bought from China, and even photovoltaic power generation equipment is bought from China and sent to Argentina, but resources such as natural gas are cheaper than China. Other costs are not easy to compare.
If all accessories are purchased in China, it will increase the freight and customs declaration fees, and the cost may be higher. Lithium extraction from mica: The grade of raw mica ore in China is relatively low, and there are very few mines that can reach more than 0.8%. If the standard is lowered to 0.3% and 0.4%, although there are more mines, the yield is low, and some are used.It is 2.2 lithium oxide ore to produce lithium carbonate and lithium hydroxide, so the output of mica lithium extraction will be limited by the grade. If you use ore with a grade of 0.4, 8 tons of raw ore to make 1 ton of concentrate, 25 tons of concentrate and 1 ton of lithium carbonate, and 200 tons of concentrate and 1 ton of lithium carbonate, obviously the lower the grade, the greater the difficulty in production.
4. The impact of environmental protection on the way of lithium extraction
The goal of carbon peaking and carbon neutrality requires some changes in lithium extraction methods to save energy and reduce the use of water resources. For example, Ganfeng has a water recycling project that needs to recycle more than 1 million tons of water. At the same time, there is also a development effort for energy conservation and environmental protection, such as using photovoltaic power generation instead of thermal power generation. Specifically, there are 3 ways to lithium extraction.
① Lithium extraction from salt lakesThere are currently certain restrictions, but the impact is relatively light. The comprehensive utilization of elements in brine will be considered in the construction of salt fields. For example, in the development of brine in Chile, potassium is extracted first and then lithium is extracted. For example, the use of adsorbents After adsorption, it is discharged into the salt field without adding organic matter or other impurities, so it has no impact on the salt field, and has no effect from the perspective of environmental protection.
② Lithium extraction of lithium from mica
It is greatly affected, because mica contains fluorine, and the fluorine process needs to be strengthened. Otherwise, the release of fluorine will pollute the environment. At the same time, because the lithium extraction from mica is currently carried out by sulfuric acid, the waste residue contains sodium, potassium and calcium.
Besides, there are also some companies which have rich experience in lithium extraction from mica. You can read our top 5 mica lithium extraction companies article to know what the companies are. It is also unfavorable for the cement industry that uses these waste residues, and the amount of waste residue is gradually increasing. The digestion capacity of the cement industry is limited, and the remaining slag still needs to be treated.
③ Lithium extraction of lithium from oreThere are not as many impurities as lithium extraction from mica in the waste residue, only hydrogen is in it, but it has some influence on energy consumption (natural gas and coal gas), exhaust emission and water emission.
5. Lithium resources continue to be in short supply
Demand side: From the perspective of the expansion rate of cathode materials, especially lithium iron phosphate, in the second half of this year, the demand for lithium salts will increase, and the situation of short supply will continue. Even before 2030, there is no particularly large supply that will lead to oversupply. The current situation is very favorable for the development of lithium salt, and the price is expected to remain in the range of 100,000-120,000 yuan/ton.
Supply side: Other countries such as Galaxy Australia, Tellison and Pilbara can provide stable supply, and it is not ruled out that they will gradually release production capacity in 2-3 years in the future. At the same time, Mali, Congo (DRC) and Brazil in Africa are also expected to start releasing spodumene in 2023. For example, the reserves of AVZ in the Democratic Republic of the Congo are particularly large, with more than 200 million tons of raw ore. The overall supply of lithium will increase in the future, but compared with demand, It's hard to balance.
6. The effect of solid-state and sodium-ion batteries on lithium
The development of solid-state batteries has a positive impact on lithium resources. The commercialization cycle of pure solid-state batteries is still relatively long, and it may not appear until 2028-2030. However, the hybrid solid-state battery can improve the performance of the battery by increasing the energy density and enhancing the safety performance through metal lithium and reducing the electrolyte.
At the same time, since the negative electrode of the hybrid solid-state battery is made of metal lithium, the positive electrode changes little, and the electrolyte uses a solid electrolyte, and the solid electrolyte is generally an oxidized or sulfided solid electrolyte, so its lithium content will be more. The development of sodium-ion batteries has restrained the demand for lithium to a certain extent, but from the current overall point of view, sodium-ion batteries are not suitable for all application scenarios.
They can be used in energy storage or two-wheelers, but are restricted in many other fields. In addition, sodium-ion batteries need to be promoted on a large scale to reduce costs, and considering the overall system cost, taking a lithium battery system as an example, the battery cost only accounts for 60%, and the remaining 40% is the management system cost. The required management costs are higher, so the total cost is still not low. Despite the differences between solid state battery and sodium ion battery, there are also differences between solid state battery and lithium ion battery. You can click our article of solid state batteries VS lithium ion to find the differences.
7. The bottleneck of battery recycling business is dismantling
With the rise in price, whether it is lithium iron phosphate battery or ternary battery, the recycling value has been greatly improved. At present, the biggest limitation is dismantling. Battery recycling mainly includes two main methods.
Fire method: The waste battery is calcined into iron ingots in a furnace, and then the metal is recovered by acid melting, but this method is difficult to recover lithium, because the lithium will volatilize during the calcination process. Other countries like Umicore in Belgium mainly use this approach.
Dismantling method: The mainstream method in China, dismantling the waste battery and removing the shell, calcining the cell in a kiln and then grinding, separating copper and aluminum, and recovering nickel, cobalt and lithium through acid dissolution.