Abstract
Matthew Hudder1*, Lucie Morin1, Sanaz Mosadeghsedghi1, MohammadAli Baghbanzadeh1, Charbel Atallah1, Seyedeh Laleh Dashtban Kenari1, Konstantin Volchek1, Matt Narrol2
1CanmetMINING, Natural Resources Canada, 555 Booth Street, Ottawa, Ontario, Canada K1A 0G1
2KMX Technologies, 1081 Britannia Road East, Mississauga, Ontario, L4W 3X1
*matthew.hudder@nrcan-rncan.gc.ca
Due to unique environmental conditions, geography, and lithium concentrations, conventional evaporative processes are not feasible for the recovery of lithium from geothermal and petroleum-based brines in Canada. The development of novel direct lithium extraction (DLE), separation, and purification technologies will assist in reducing water consumption, land use impacts, and waste generation for the recovery of lithium from these brines.
A vacuum membrane distillation (VMD) process was developed in a joint collaboration and operated at pilot-scale to concentrate lithium brine samples following pre-concentration using DLE and reverse osmosis. Two industrial brine samples with varying total dissolved solids (TDS) and lithium concentrations of 66.1 g/L, 1240 ppm and 48.1 g/L, 259 ppm were successfully processed to high lithium chloride concentrations using the VMD pilot unit.
A hollow fiber, polytetrafluoroethylene (PTFE) membrane was used to concentrate the two 1,000-liter samples. Between 83% and 85% of the water in the samples was recovered as permeate with TDS concentrations below 50 ppm using VMD, with greater than 99.99% of dissolved ions retained in the concentrate. The rejected ions include high concentrations of calcium, magnesium, and ammonia, which present a challenge for conventional pressure driven technologies. Both samples were concentrated to the point of saturation of sodium chloride, with TDS concentrations of 327 g/L and 331 g/L respectively. Further studies to optimize the performance of VMD and its integration with DLE and post-DLE technologies are ongoing.