New Advances in Lithium Extraction from Salt Lake Brine

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On October 17, the Qinghai Lithium Magnesium-Lithium Separation Project, funded by TUSI Water Shanghai Co., Ltd. and implemented under the EPCM model by Beijing Anyuan Yangguang Petrochemical Engineering Technology Co., Ltd. and Beijing Bipaike Project Management Co., Ltd., was successfully put into operation and began producing qualified products. Since 2016, with the vigorous promotion of new energy electric vehicles, the price of lithium carbonate, which is used in lithium batteries, has risen sharply from 30,000 yuan per ton to 172,000 yuan per ton. The price of lithium carbonate has been on the rise. The production of lithium carbonate mainly follows two primary processes: the extraction of lithium from ores using sulfuric acid, and the extraction of lithium from salt lake brines. The traditional method of extracting lithium from ores via sulfuric acid has limitations such as high energy consumption, numerous processing steps, high costs, and limited ore reserves, which restrict its further development. With the success of lithium extraction from salt lake brines in South America, this method has rapidly become the dominant approach for producing lithium carbonate. China possesses abundant salt lake resources and large deposits of lithium carbonate. However, since companies such as Lankemo Lithium, CITIC Guoan, and Qinghai Lithium were established in China starting in 2005 to engage in lithium extraction from brines, the high magnesium-to-lithium ratio in China’s salt lake brines (500:1) – compared to 100:1 in those of South America – has led to problems such as insufficient production capacity and low purity among Chinese companies involved in this process, thereby severely hindering the development of lithium carbonate production from salt lakes. The magnesium-lithium separation unit developed by Qidi Water Treatment involves adding a nanofiltration membrane separation system to the first-phase lithium carbonate production project of Lankē Lithium Industry, thereby increasing the annual production capacity of lithium carbonate from 2,000 tons to 8,000–10,000 tons. It can also achieve the energy-saving and environmental protection goal of saving 300 liters of water per ton of lithium carbonate. At present, the magnesium-lithium separation unit developed by Qidi Water has been successfully put into operation, and the performance of all products meets the design requirements. Qinghai Qidi Water Treatment’s magnesium-lithium separation project has completely resolved the key technical challenges that have long plagued lithium extraction from salt lake brines in China, opening up a new shortcut for such extraction. Relying on the magnesium-lithium separation technology provided by Qidii, Qinghai Salt Lake Group has recently begun preparations for a second-phase project that will enable annual production of 30,000 tons of lithium carbonate and 10,000 tons of lithium hydroxide, as well as a project for producing metallic lithium. By then, the Salt Lake Group will have an annual production capacity of 100,000 tons of lithium metal-related products.