RECOVERY AND SEPARATION OF VALUABLE METALS (COPPER AND ZINC) FROM ACIDIC MINE WATERS BY ION-EXCHANGE RESINS

Mining wastewaters, containing heavy metals such as copper (Cu) and zinc (Zn), have a huge impact on the environment due to they are not biodegradable and tend to bioaccumulate in plants or living organisms. Therefore, in this work the performance of ion-exchange and solvent-impregnated resins were compared for the separation and recovery of valuable metals (Cu, Zn) from acidic mine waters (AMW). Lewatit 207 as an ion-exchange resin, and an impregnated resin containing Di-2-ethylhexylphosphate, named Lewatit 1026, were evaluated for extract both metal ions. Additionally, the metal extraction was determined as a function of pH (from 1 to 5) when an AMW was used to carry out the experiments. Batch experiments results showed that best extraction of Zn was obtained using Lewatit 1026 being around 96% (pH=2.5-3); whereas Lewatit 207 performance was optimum for Cu extraction (about 99%) at pH=3-4. Moreover, using a fixed-bed configuration column, it was possible to separate and concentrate Zn (10 times) and Cu (40 times) by using Lewatit 1026 and 207, respectively. Overall, the application of an ion-exchange process showed a great potential in the recovery of valuable metals from mine waters to promote a circular economy scheme in the metallurgical industries.