Great innovation has taken place in the technology of extracting lithium from salt lake brine.

On May 26, led by Minmetals Salt Lake Co., Ltd. (hereinafter referred to as "Minmetals Salt Lake") and developed in cooperation with Xi'an Lanshen Environmental Protection Technology Co., Ltd. (hereinafter referred to as "Xi'an Lanshen"), the project "Research on High efficiency Lithium extraction from Salt Lake Brine" has passed the expert review organized by Qinghai Provincial Department of Science and Technology in Beijing. Zheng Mianping, academician of the Chinese Academy of Engineering, and other experts agreed that this technical route is advanced and reasonable, has conquered the efficient lithium extraction technology from the original brine, has obvious technological innovation, has reached the domestic leading level, and has achieved remarkable achievements. it is of great significance to the salt lake lithium extraction industry in China and even in the world, and it is suggested to accelerate the industrial application of lithium extraction from salt lakes.

According to experts, the technology of extracting lithium from salt lakes with high mg / Li ratio "the world looks at China and China looks at Qinghai". The biggest highlight of Minmetals Salt Lake "Research on High efficiency Lithium extraction Technology from Salt Lake Brine" is that the old brine after sodium and potassium precipitation is exposed from the salt field stalls commonly used in Qinghai Salt Lake, and then magnesium and lithium are separated by the workshop, and the industrial lithium extraction technology route of lithium extraction after concentration is changed. The separation of sodium, magnesium, potassium and lithium and the concentration of boron and lithium are realized directly from the original brine, which greatly improves the overall yield of lithium ion. In addition, the continuous separation equipment is successfully applied to this lithium extraction process. The device efficiency and automatic control are improved, and it has obvious advantages such as high efficient extraction of lithium from complex brine system, short production cycle, improving the effective service life of resources, friendly to the environment and so on.

According to the main technical person in charge of Minmetals Salt Lake, the technological innovation of Minmetals Salt Lake is a concrete embodiment of the spirit of General Secretary Xi Jinping's instructions on the scientific development of Qinghai Salt Lake and the enterprise concept of "cherishing the limited and creating the infinite" of China Minmetals. With the strong support of governments at all levels in Qinghai Province and Minmetals Salt Lake shareholders, the technology research was launched in 2019. Combined with the advantages and disadvantages of the industrialized salt lake lithium extraction process, the upgrading process technology scheme was determined, with emphasis on increasing the primary yield of lithium. Improve plant efficiency, improve product quality, reduce consumption for the purpose of scientific research, mainly save the salt field drying process with long separation and concentration time and low yield. Shorten the original 2-year production cycle to 20 days.

The key of this process is that in March 2020, in cooperation with Xi'an Lanshen, we first developed an adsorbent that can separate lithium from potassium, sodium and magnesium at the same time, completed a small-scale experiment on a continuous separation adsorption device, and explored the optimum adsorption process conditions. the adsorption capacity, adsorbent strength and resolution were verified. The small-scale test was completed and the expert acceptance appraisal was carried out in July 2020, and the engineering industrialization experiment was started according to the results of the small-scale test. In April 2021, a nearly 1000-ton industrial production line was built and put into operation. From the operation in the past two months, the operation of the production equipment is continuous and stable, and various indexes are better than those of the feasibility study, and very good results have been achieved. Due to the realization of the front position in the process of this project, the salt field spreading is omitted, and the optimal combination mode of the membrane system is improved, the device efficiency is improved, the production capacity is increased by 1.5 times, the power consumption is reduced by more than 30%, and the "three wastes" zero emission is obvious. the effect of energy saving and emission reduction is obvious, and the overall cost is reduced by more than 10%, especially the total lithium extraction rate is increased to 2 times to more than 70%, in the case of the same scale, The service life of the mine has been doubled and extended, which has greatly improved the effective utilization of resources. At the same time, the product quality is further improved, and batch consistency is improved, which can fully meet the standards for the production of high-end materials for new energy lithium batteries and improve the added value of the products.

It is understood that at present, the process upgrading and expansion project of the 10,000-ton plant in Minmetals Salt Lake is advancing rapidly. with the comprehensive promotion and application of this technology, it can promote the comprehensive and efficient development of lithium resources in Yiliping Salt Lake and even the entire salt lake industry, effectively ensure the strategic security of national lithium resources, and effectively support the development of the national lithium power new energy industry.