Highly Efficient Separation of Magnesium and Lithium and High-Valued Utilization of Magnesium from Salt Lake Brine by a Reaction-Coupled Separation Technology

Abstract

Lithium extraction from salt lake brines is one of the most important pathways for obtaining Li-related products, e.g., Li2CO3 and LiOH, and for further fabricating electric energy-storage products, e.g., lithium ion batteries. The high Mg/Li ratio and high Mg content are remarkable characteristics of the salt lakes in the Qaidam Basin in China, making the Mg/Li separation and Li extraction rather difficult. Herein, we proposed a reaction-coupled separation technology for Mg/Li separation from brine with a high Mg/Li ratio. The core idea of this technology is that the Mg2+ cations were reacted to form a solid via a nucleation–crystallization separation method. The solid product was MgAl-layered double hydroxide (MgAl-LDH), a widely used and high-valued product in the family of LDHs. The Li+ cations were left in the solution after Mg2+ cations were reacted with alkali solution, accompanied by foreign Al3+ cations. That is to say that the Mg2+ cations can be incorporated into the layers of MgAl-LDH while Li+ cations cannot. The findings indicated that Mg2+ cations were almost completely extracted into the solid phase to form the LDH. The Li+ cations remained in the solution having a weight loss less than 8%, which is an excellent level of Li extraction from the brine with a high Mg/Li ratio. The effects of reaction parameters, e.g., ionic strength, nucleation rotating speed, Mg/Al ratio, and crystallization temperature and time, on the separation performance and lithium loss were investigated. The optimal conditions were derived for lower lithium loss and more outstanding Mg/Li separation performance, which can be a useful guide for environmentally friendly and sustainable Li extraction from the brine.

Highly efficient extraction of lithium from salt lake brine by LiAl-layered double hydroxides as lithium-ion-selective capturing material

“…The Na/Li ratio reached 48.7 in weight after separating Mg 2 + ions from East Taijinar salt lake brine [31] . The concentrations of Li + and carbonate ions in the brine are 0.675 g/L and 8.57 g/L, respectively.…”

“…In our previous study, we proposed a new reaction-coupled separation technology to simultaneously separate Mg 2 + and Li + ions and retrieve magnesium resources from East Taijinar salt lake brine with a high Mg/Li ratio [31] . The core idea is that Mg 2 + ions can selectively enter the solid phase to form a MgAl-layered double hydroxide (MgAl-LDHs), while Li + ions cannot.…”

Materials for lithium recovery from salt lake brine

“…in salt lake brines, which are typically rich in Mg 2? [19][20][21][22]. To extract high-purity lithium products from salt lake brines, it is necessary to separate lithium from other coexisting ions.…”

Preparation of Sulfonated Polyarylene Ether Nitrile Hollow Fiber Membrane Adsorbent and Its Potential in Separation Lithium Ion from Brine

“…Lithium is widely used in production and life, such as nuclear energy, batteries, aviation, metallurgy, medicine and electronic equipment. [1][2][3][4][5][6][7][8] Especially with the rapid development of the lithium battery industry, people's demand for lithium resources is increasing year by year. It is estimated that by 2025, the global lithium consumption used only for lithium batteries will increase to 65 % compared to 35 % in 2015.…”