Aiming towards a zero-waste strategy for the recovery of metals from battery refining waste waters, LEITAT is working on the development and evaluation of novel polymer inclusion membranes (PIM). PIMs are a type of liquid membrane in which the liquid phase, the extractant, is held within a polymeric network. The interest in these membranes has been growing exponentially over the past few years as an alternative separation technique to conventional solvent extraction.
Work during the first six months has focused on the evaluation of different extractants for the target metals: lithium, manganese, cobalt and nickel. Researchers established a liquid-liquid extraction protocol based on two different processes in which the target metal is extracted and recovered separately. During the extraction step, a specific carrier compound selective towards the target metal separates an amount of it from a feed metal solution. The recovery of the metal takes place in the second process, where a stripping solution is employed to recover the metal previously extracted through the carrier. Initial PIMs containing the most efficient extractants have been prepared, characterised and are currently evaluated. The featured image depicts the continuous procedure used to test the synthesised PIMs.