Technologies for Boron Removal from Lithium-Rich Brines: A Review

The growing demand for lithium for lithium-ion batteries and energy storage systems has driven the exploitation of natural brines in the “Lithium Triangle” (Chile, Argentina, Bolivia). However, the presence of boron, which is highly soluble and exhibits amphoteric behavior, poses a critical challenge to achieving battery-grade purity standards (<5 ppm). This element interferes with the crystallization and morphology of lithium carbonate (Li2CO3), reduces recovery efficiency, and affects the chemical stability of lithium phases. Due to its molecular characteristics and strong affinity for water, boron is difficult to remove using conventional methods. This work presents a critical review of current technologies for its removal from lithium-rich brines, including ion exchange with functionalized resins, adsorption, liquid–liquid extraction, and electrochemical methods. Their principles, efficiencies (60%–95%), selectivity towards Li+ and Mg2+, sustainability, reusability, and industrial feasibility are analyzed. A comparison shows that ion exchange and adsorption offer high selectivity and reusability, liquid–liquid extraction stands out for its efficiency but has lower sustainability, and electrochemical methods exhibit high sustainability with variable efficiency. The choice of the most suitable technology will depend on the specific composition of the brine and the operating conditions of the plant.