Producing battery grade lithium carbonate from salt-lake brine via bipolar membrane carbon dioxide mineralization

Abstract

Producing battery-grade Li₂CO₃ product from salt-lake brine is a critical issue for meeting the growing demand of the lithium-ion battery industry. Traditional procedures include Na₂CO₃ precipitation and multi-stage crystallization for refining, resulting in significant lithium loss and undesired lithium product quality. Herein, we first proposed a bipolar membrane CO₂ mineralization technique for directly producing battery-grade Li₂CO₃ from lake brine that enriches alkali metals (Na⁺, K⁺). Results indicate the process can successfully separate Li⁺ from contaminants and present a selectivity above 900 for Li⁺ through the CO₂ mineralization reaction, while prevent electro-oxidating Cl⁻ to Cl₂ pollution. The obtained Li₂CO₃ production purity is above 99.75% with lithium recovery rate of 86%. Carbon dioxide was captured in the form of Li₂CO₃, with a capacity of 595 g of CO₂ for1 kg of Li₂CO₃. The technology provides a sustainable and cost-effective path for producing battery-grade Li₂CO₃ from the lake brine.