Reacción a "Two low-pollution alternatives proposed to extract lithium from diluted brines like seawater"

The study offers a technological proposal to extract lithium using an electrochemical method that operates similarly to a battery. The novelty of the cell used is that it avoids the use of membranes (and the disadvantages associated with them) and consists of a simple, easily scalable design. The work is important because it reports the extraction of lithium from diluted solutions and takes advantage of the osmotic potential between the brine and the extraction water to reduce energy consumption.

The device was tested using both synthetic and natural brines (from the Dead Sea) at laboratory and pilot plant scales, achieving lithium recovery rates of over 90% at the laboratory scale and 80% at the pilot scale, while also saving 21% of energy costs. The lithium selectivity values were higher than those of other electrochemical methods that use membranes, and the calculated extraction cost was competitive with that of lithium extraction from conventional resources.

However, when evaluating direct lithium extraction technologies, it is crucial to consider other parameters beyond just economic cost, energy consumption, or lithium recovery performance. For example, there is no explicit calculation of the amount of fresh water the process requires. In fact, the authors mention that due to time limitations, they did not reach the necessary lithium concentrations to later precipitate it as Li2CO3 by adding Na₂CO₃ (the final product for commercialization) and therefore used a solar evaporation stage. Direct lithium extraction technologies should avoid water evaporation entirely, whether in the pre-concentration stages or in obtaining the final product. Additionally, it is crucial to develop technologies that move towards the simultaneous recovery of as many by-products as possible from a single deposit. These perspectives are fundamental for drastically reducing the consequences that lithium-related mining activities generate in the territories.