Abstract
Critical minerals mining and processing, such as lithium, generate wastewater streams containing several metals in significant concentrations. These metals are targeted as a source of acute toxicity for aquatic species, resulting in ever more stringent discharge criteria. These metals should therefore be removed, while considering that each of these metals requires very specific conditions for optimal removal.
This study presents how these metals can be effectively removed in a reduced footprint. The goal is to present what needs to be considered for a greater understanding of the water chemistry, as well as the strategic approach that can be used for reduction of treatment steps while meeting the most stringent criteria. The combination of metal precipitation mechanisms with specific chemistry will be approached, as well as the efficiency of ballasted flocculation for maximal solids and precipitates removal.
The presentation will focus on how metal removal can be approached using physico-chemical technologies, with the various precipitation mechanisms available, and how to efficiently combine these mechanisms to reduce the required treatment step for the mine wastewater treatment plant. A case study will be presented to illustrate this quest to reach ever lower effluent metal concentrations in applications where so many different metals need to be removed on a design point of view for a lithium mining application.