Current Status of Lithium Resources and Development in Salt Lakes in my country
Hou Zhaoping stated that there are currently two types of lithium deposits that can be developed and utilized globally: one is brine lithium deposits in salt lakes, and the other is rock lithium deposits. Among them, brine lithium resources in salt lakes account for more than 70% of the total resources and are mainly distributed in Chile, Bolivia, Argentina, my country, and other places.
my country's lithium salt lake resources are mainly distributed in Qinghai and Tibet. Among them, Qinghai's salt lake resources include 10 lithium deposits with documented mineral reserves, with proven reserves of 24.4738 million tons of lithium chloride. There are two super-large deposits, the Qarhan Salt Lake and the Beltan mining area, and three ultra-large deposits, the Xitai, Dongtai Jinaier Lake, and the Yiliping mining area. The 10 salt lakes contain 8.92 million tons of lithium resources with industrial-grade lithium content, which are available for development and utilization.
Tibet's salt lake resources are mainly distributed in the northern region. Among them, there are 80 salt lakes with brine lithium content reaching the industrial grade, including 8 large-scale ones, with LiCl reserves of 17.3834 million tons. Important deposits include the Zabuye, Longmu Co, Jieze Chaka, Laguo Co, and Eya Co salt lakes.
Development history and cost evolution of lithium extraction technology from salt lakes
Before the 1960s, research on brine lithium extraction technology had begun, with the United States undertaking considerable work in this area. However, most of this work remained at the research and development stage and failed to translate into practical applications. After 1974, the discovery of abundant brine lithium resources in salt lakes spurred development and investment enthusiasm from some of the world's largest brine lithium resource countries and lithium mining companies. Following 1980, companies such as Fort Cyprus and FMC began a major foray into brine lithium extraction, marking the beginning of the industrialization of brine lithium extraction.
Lithium extraction technologies from salt lakes mainly include precipitation, solar pond, extraction, calcination, adsorption, molybdenum (MO) method, and other new lithium extraction technologies.
Precipitation method
Precipitation is only suitable for salt lake brines with a Mg2+/Li+ ratio of less than 10. Therefore, this technology has been applied in salt lakes with low Mg2+/Li+ ratios, such as the Atacama, Silver Peak, and Umbremuerto in South America. This technology can achieve magnesium-lithium separation during the salt field process and concentrate Li+ to over 30 g/L. Subsequent processes only require deep impurity removal to meet production needs. It has advantages such as simple technology, low energy consumption, and low investment.
Due to these advantages, as early as 1986, Fort Cyprus ceased its domestic lithium extraction industry from spodumene and invested in lithium carbonate processing plants in Silver Peak, Nevada, and the Atacama Salt Flat in South America, thus initiating the era of brine lithium extraction. In 1997, SQM successfully extracted lithium from the Atacama Salt Flat in Chile, reducing the price of lithium carbonate to $1,500/t (while the international price was $3,300/t at the same time), significantly impacting the hard-rock lithium industry worldwide. In 2018, Albemarle, SQM, Livent, and Orocobre, four brine lithium extraction companies, produced a total of 158,000 tons of lithium chemical products using this technology, accounting for 52.4% of the global lithium supply, with a production cost of approximately $3,000-$5,000/t, giving them a certain advantage in the industry. Because the technology is simple and mature, its cost structure has remained largely unchanged for nearly 40 years; price fluctuations are mainly due to inflation and rising labor costs.
Sun pool method
This process technology was developed for carbonate-type salt lakes with extremely low Mg2+/Li+ ratios (≤0.1). Because carbonate-type salt lake brine has extremely low magnesium content, direct solar evaporation of the brine yields 60% to 70% lithium carbonate crude ore. Subsequent purification of the lithium carbonate crude ore is then sufficient to obtain battery-grade lithium carbonate products.
In March 2003, the Zabuye Salt Lake launched the first phase of its lithium carbonate project using this technology, and successfully completed trial operation in August 2005. However, due to the presence of carbonate ions in the salt lake leading to significant losses during the brine drying process, coupled with high altitude (above 4000 meters) and poor infrastructure, production growth has been limited. Currently, the designed output remains at 3000 tons per year, with a total lithium salt production of 2728 tons in 2017. Since the technology has not undergone significant changes in the past decade, the cost structure has not changed substantially, with current production costs estimated at approximately 15,000-20,000 yuan.
Extraction method
The technology of lithium extraction from brine by solvent extraction has been studied for more than 40 years, and has been carried out by institutions such as US lithium companies, Shanghai Institute of Organic Chemistry of Chinese Academy of Sciences, and Qinghai Salt Lake Institute of Chinese Academy of Sciences.
Currently, the Da Qaidam Salt Lake has built an industrial-scale plant using this technology, successfully producing lithium chloride and lithium carbonate. However, in the early stages, the process suffered from problems such as high extractant prices, large losses, and equipment corrosion, leading to inconsistent production and costs that once reached as high as 60,000 yuan. In recent years, with continuous advancements in the technology, the current production cost is approximately 40,000 yuan.
Calcination method
The calcination method is a technology proposed for high-magnesium-lithium ratio brine from salt lakes. Because the final brine (old brine) from high-magnesium-lithium salt lakes, after evaporation and concentration, is a lithium-rich saturated solution of magnesium chloride. Magnesium chloride decomposes into magnesium oxide and hydrogen chloride gas above 550°C, while lithium chloride does not decompose under these conditions. The calcined sinter is leached; lithium salts, readily soluble in water, enter the solution, while magnesium oxide, almost insoluble in water, remains in the slag. The leachate contains sulfate, magnesium, and small amounts of boron, among other impurities. After purification of the filtrate, evaporation, alkali precipitation, and drying, lithium carbonate is obtained.
From 2007 to 2011, a calcination process production line was built at the Xitaijinaier Salt Lake. In the early stages of the project, issues with equipment material selection, hydrogen chloride recovery, and magnesium slag recovery led to unsustainable production and costs exceeding 80,000 yuan. In 2015, with the booming lithium salt market, the company initiated several technological research and development and upgrade projects. After the upgrades were completed in 2016, the problems affecting the process were improved, and production costs dropped to around 40,000 yuan (comparable to the costs of most ore-based lithium extraction companies). In particular, product quality improved significantly, and the products are now being used by some large and influential battery material manufacturers such as Beijing DangSheng Technology.
Adsorption method
mo method
In 2007, a 3000t/mol process production unit was successfully built at the Dongtai Jinai'er Salt Lake. Initially, the project faced challenges due to unstable operation and high membrane consumption, resulting in costs exceeding 60,000 yuan. Later, with improved understanding of the electrodialysis membrane system and upgrades in membrane manufacturing technology, the operational instability was gradually resolved, and production costs dropped significantly to around 20,000 yuan, offering a substantial cost advantage over ore-based lithium extraction. In 2012, a new 7000t production line was successfully built and put into operation. After several years of upgrades and improvements, the two production lines, with a combined output of 10,000t, can now produce lithium carbonate with a main content greater than 99.6% in a single batch. The product quality fully meets the "Local Standard for Brine Battery Grade Lithium Carbonate," and 90% of the products are sold to battery material manufacturers. Representative downstream customers include Peking University Pioneer, Tianjin Bamo, Shanshan, and Beijing DangSheng.
The newly built 10,000-ton production line of Qinghai Dongtai Jinaier Lithium Resources Co., Ltd. has been completed and put into operation. To date, the industrial-scale production capacity of facilities built using this technology has reached 20,000 tons per year.
Other new lithium extraction technologies
1. Lithium-ion sieve adsorption technology for lithium extraction
Ion sieves are novel synthetic materials capable of introducing target ions into inorganic compounds and reacting them to form composite oxides. These materials can form spatially matched cavities with target ions without damaging the structure, enabling selective identification and sieving of target ions in environments where multiple ions coexist.
Common lithium-ion sieves include manganese-based and titanium-based lithium-ion sieves. Compared with aluminum-based lithium adsorbents, these materials have the advantage of large adsorption capacity, but they also suffer from severe dissolution. In recent years, scientists have developed advanced materials such as lithium-ion sieve membranes and lithium-ion sieve nanotubes to address the dissolution problem of lithium-ion sieves. Currently, these materials are still in the research and development stage.
2. Electrochemical deintercalation/intercalation method for lithium extraction from salt lakes
Professor Zhao Zhongwei's team at the School of Metallurgy and Environment, Central South University, has creatively invented a new "electrochemical deintercalation method for lithium extraction from salt lakes" by applying the working principle of lithium batteries to the selective extraction of lithium from salt lake brines. Based on this innovative approach, they have constructed a new electrochemical lithium extraction system consisting of "lithium-rich adsorbent materials | supporting electrolytes | anion exchange membranes | brine | lithium-deficient adsorbent materials." After nearly ten years of research, they have achieved highly selective, low-cost, and green extraction and enrichment of lithium from salt lake brines.
In 2017, the technology was transferred to Shanghai Danhua Technology Development Co., Ltd. (transfer fee of 104.8 million yuan), and Jiangsu Zhongnan Lithium Industry Co., Ltd. was jointly established by Shanghai Danhua and Central South University to continuously develop and promote the technology. It is reported that the technology transfer has completed industrial-scale testing, and key equipment for the second-generation electrochemical intercalation-deintercalation membrane stack electrolyzer and intelligent expert control system have been developed. Furthermore, a technology cooperation agreement has been signed with relevant companies for a project with an annual production capacity of 20,000 tons of lithium carbonate.
Outlook
Over the past decade, while significant progress has been made in lithium extraction technology from high-magnesium-to-lithium ratio brine lakes, there is still considerable room for improvement in production costs compared to low-magnesium-to-lithium ratio brine lake extraction in South America. In the future, with the accelerated development of lithium resources and the release of production volumes, if market prices continue to decline, many companies with high costs and limited resources will find it difficult to survive, and may even face losses and production stoppages.
In order to achieve sustainable development in the face of fierce market competition, increasing investment in science and technology, upgrading and optimizing processes, improving product quality, and reducing production costs are issues that every high magnesium-to-lithium ratio lithium extraction company in salt lakes must consider.
1. Modify product standards in a timely and appropriate manner.
Early lithium salt technology originated from the ore-based lithium extraction method. Lithium-bearing ores contained extremely low levels of boron and chloride ions. Against this backdrop, the industry standard for battery-grade lithium carbonate (YS/T582) was developed, with very high requirements for impurities such as boron and chloride ions (≤30ppm). But are these stringent boron and chloride ion requirements truly necessary for battery-grade lithium carbonate?
Currently, lithium extraction technology from salt lake brine struggles to meet the boron and chloride requirements specified in YS/T-582-2013, necessitating secondary purification and resulting in significantly high production costs. To effectively address the common boron and chloride issues encountered in the lithium industry related to salt lake lithium extraction technology, it is recommended that the government, industry associations, and upstream and downstream companies utilize necessary means to investigate the impact of boron and chloride on battery-grade lithium carbonate, and revise current product industry standards appropriately and in a timely manner. Developing more scientific product quality standards will promote the widespread application of salt lake lithium products in the battery field.
2. Comprehensive development and utilization of salt lake resources
Salt lake resources contain important elements such as sodium, magnesium, potassium, lithium, and boron. Among these five elements, the development and utilization of magnesium and boron resources are the bottlenecks in the development and utilization of salt lake resources. If the development problems of magnesium and boron resources are solved, the difficulty of developing and utilizing other elements will be greatly reduced. At the same time, magnesium products are diverse, have a wide range of applications, and high added value, thus having greater economic development and utilization value.
The development and utilization of magnesium and boron resources is expected to transfer the costs of separating high magnesium-to-lithium ratio magnesium and lithium and removing boron to magnesium and boron products. At that time, the production cost of lithium products will be greatly reduced, making them competitive with South American salt lakes.
3. Direct lithium extraction technology from raw brine
Traditional lithium extraction technology from salt lakes uses the old brine obtained after sodium and potassium removal through salt field drying as raw material. Typically, some lithium resources are lost during the salt field drying and brine extraction and transportation processes, primarily due to seepage from the salt field and losses carried over by sodium and potassium salts.
Lithium extraction by adsorption of raw brine uses the original brine as raw material, effectively avoiding losses in the salt field process, greatly improving the lithium resource yield, extending the resource service life, expanding the production scale, and reducing production costs.
In recent years, with the development of adsorption lithium extraction technology, many research institutions and companies have developed lithium-sodium separation resins suitable for lithium extraction from raw halogens and have achieved certain results in the field of lithium extraction from raw halogens. Currently, many companies are working tirelessly to tackle related scientific and technological challenges.
4. Emphasize scientific and technological research and development, and learn from others' strengths to make up for weaknesses.
Currently, there are certain gaps in the quality of first-pass lithium carbonate products and battery material requirements among these different lithium extraction (lithium carbonate) processes. The main reason is that the characteristics of the raw materials in the salt lake brine and the problems in process control result in high levels of Na+, Mg2+, Cl-, and B in the produced lithium carbonate products. Some processes produce lithium carbonate products with a main content between 98% and 99.5%, which cannot be directly applied to the lithium battery material industry.
Therefore, while increasing investment in scientific and technological research and development, learning from each other's strengths and weaknesses among various mature lithium extraction technologies from salt lakes will help improve product quality and reduce production costs.
5. Differentiated competition
Currently, whether lithium extraction is done through ore or salt lakes, the main products are lithium carbonate and lithium hydroxide. Lithium carbonate, in particular, faces significant homogeneous competition, hindering the industry's healthy development. If major lithium salt producers could differentiate themselves by using raw materials with unique characteristics, it would benefit the industry. For example, producing lithium hydroxide from ore, lithium carbonate from carbonate-type salt lakes (such as Zabuye in Tibet), and lithium phosphate from Qinghai salt lakes would not only leverage their respective strengths but also mitigate the pressure from homogeneous competition.
The novel coronavirus outbreak at the end of 2019 had a significant impact on the global economy, and the lithium industry was no exception. However, the lithium industry is, after all, a new energy industry and a sunrise industry; societal development cannot be separated from energy, especially new clean energy. From the current situation, the slight decrease in lithium sales caused by the epidemic in the short term will not affect the industry's development trend or price changes. Currently, the lithium battery industry has entered a growth stage and will encounter some difficulties. However, with the development of lithium extraction technology from salt lakes, the difficulties and problems faced by existing high magnesium-to-lithium ratio salt lake lithium extraction technologies will be resolved. We firmly believe that the lithium battery industry has enormous development potential in the future. Let us work together to create a better tomorrow for the lithium battery industry!
