Development of a hydrometallurgical process to recover lithium from industrial wastewater

Details

Supervisors

Henry, Philippe ; Proost, Joris ; Marenne, Amélie

Faculty

Ecole polytechnique de Louvain

Degree label

Master [120] : ingénieur civil en chimie et science des matériaux, à finalité spécialisée

Abstract

Lithium is a critical material with growing demand for use in lithium-ion batteries (LIBs). As natural sources of lithium are depleting and spent LIB waste accumulates, the recycling of lithium has become a pressing concern. In this work in collaboration with Hydrometal Belgium, a sodium aluminate co-precipitation process was employed to recover residual lithium from industrial effluents at three levels. First, the process was applied to a crafted solution containing 10 mg/L of lithium. Next, it was tested on the effluent of a lithium carbonate precipitation process with 1.6 g/L of lithium. Finally, a phosphate and aluminate mixed precipitation was tested at 70 ◦C on the same effluent. The first tests revealed that the composition of the wastewater greatly influence the lithium recovery. A large excess of precipitant brought the lithium concentration of the crafted solution below 1 mg/L. The influence of pH was evaluated and an optimal pH of 9.5 was found. The precipitates were weakly charged with lithium therefore the co-precipitation method was coupled with a preliminary lithium phosphate precipitation. The mixed precipitation process facilitated the lithium recovery while limiting the reagent use and the mass of precipitated solid. The use of aluminum compounds for lithium recovery should be reserved for low lithium concentration effluents. The influence of temperature on the process is an important parameter that needs to be investigated further in future research.