Direct lithium extraction from raw brine by chemical redox method with LiFePO4/FePO4 materials

In this study, a novel high-efficient approach of directly extracting lithium from the Da Qaidam artificial raw brine (the main components: Li+ 0.10 g·L-1, Na+ 82.34 g·L-1) by LiFePO4/FePO4 material through the chemical redox method was proposed. The extraction process demonstrated a fast reaction speed and expected lithium adsorption capacity which reached 9.13 mg·g−1, and the whole process could be online monitored by measuring the solution's redox potential and pH value. Besides, the adsorption process exhibited excellent ion selectivity while the separation coefficient of lithium towards sodium, potassium, and magnesium reached 8704, 2460, and 6864 respectively. This extraction method features high efficiency, facile and continuous operation, and provides an alternative pathway to directly extract lithium from raw brines.