Water Recovery Via Solar Evaporation Systems Coupled to Lithium Mining from Brines
Abstract
Extraction of lithium from continental brines is becoming a focus of importance worldwide. This is a vital raw material for the fabrication of lithium-ion batteries. The continued availability of lithium salts can only rely on a strong increase of mining and ore processing. Currently slightly more than half of the world production of lithium is extracted from brines, a practice that evaporates on average half a million litres of water per ton of lithium carbonate in highly desertic regions whit intensive solar irradiation and fresh water scarcity. Taking into account the sustainability of the overall process with particular emphasis to water usage in relation to mining processes, we observed a link between lithium extraction from brine and desalination technologies with the purpose of considering the possibility of recovering water either in the current extractive process or with new extractive technologies, achieving a double objective: pure lithium salts plus desalinated water. There are several reported desalination technologies, and considering the high salinity of lithium rich brines (on average 300 g L-1 TDS) it is necessary to determine which of the already existing desalination technologies could be efficiently merged or coupled with the lithium extraction in technical and economic terms. According to type of energy used and the climatic conditions mentioned, it is logical to think first of thermal solar desalination methods. In this work, an experimental and theoretical analysis of brine desalination in the Olaroz Salar, northern Argentina, using a simple solar still was carried out, the performance analysis based on various factors affecting the productivity were studied. The evaporation rate of the brine in the solar still was compared with the natural evaporation rate from open surface brine