Water recovery assessment from hypersaline lithium-rich brines using Membrane Distillation-Crystallization

Abstract

The current lithium extraction from hypersaline salt-lake brines is causing concerns, mainly due to the evaporation and loss of around 90 % of the water contained in the brines, tensioning the relationship between communities and industrial companies located in zones with a severe water scarcity. This study assesses the water recovery from synthetic hypersaline brines - mimicking the contents variability of Na, K, and Mg - using a Membrane Distillation-Crystallization process. An evaluation of the operational parameters of the process, such as feed temperature, flowrate and water activity was carried-out using a Response Surface Methodology. Final validation was performed to assess the process performance by comparing a real brine from Maricunga salt-lake (Chile) and a synthetic brine. An average flux of around 3.5 kg/m2 h at 60 °C brine feed temperature was obtained for real and synthetic brines, achieving a high quality recovered freshwater (electrical conductivity <40 μS/cm) and low contents of ions.