Challenge: Saline wastewater generated from lithium recovery from brines and ores
 

Lithium carbonate and hydroxide production, by conventional methods or emerging technologies (i.e., Direct Lithium Extraction “DLE”), and whether using brine resources (salt lake solutions, brines from geothermal fields, oil/gas produced waters) or mineral ores, invariably produce one or more saline waste streams that need sustainable management. Solutions are needed for:

 

• Avoiding the co-precipitation of minerals of certain co-valent elements during the lithium carbonate crystallisation step from mother liquor, to reduce costs involved with the purification of lithium product to a desired purity level.

• Remove or reducing the need for re-injection of spent brine in the case of geothermal fields to avoid rapid interference with production wells in order to avoid significant dilution of the valuable resource.

• Removal or reducing the need for discharge of spent brine to solar evaporation/crystalliser ponds to avoid brine dilution due to destratification or contamination due to leaching of used solvents, with the latter known to cause significant pH changes and devaluation of the resource.

• Value adding to operations through recovery of additional water from reject brine of desalination processes and/or production and sale of by-products to improve the overall economics, via (i) reducing the volumes of spent brines, (ii) avoiding the evaporative loss of precious water and costs with resorting to higher cost desalination processes, and (iii) improving the sustainability of the operations. 

• Enabling de-risking of the emerging technologies (like DLE) to operate at economies of scale, whilst avoiding the return of lithium-extracted brine to lakes, known to be causing dilution of the resource.