Abstract
Nickel, cobalt and manganese are all critical materials that are vital for the green transition, and their demand is expected to increase significantly in the years to come. In this work, nickel, cobalt and manganese metals are electrowon from methanesulfonic acid (MSA) electrolytes derived from processing of various industrial intermediates and tailings. Several of these raw materials, as well as many primary raw materials, contain iron that is precipitated as an oxide/oxyhydroxide and subsequently landfilled in conventional flow sheets. With the aim of implementing circular processes to maximize raw materials usage, iron metal can be recovered by electrowinning, where iron metal forms at the cathode while the acid (MSA) is regenerated at the anode.
Electrowinning experiments were performed in a small 3-electrodes cell (25 mL) and in a larger flow cell (120 mL), the latter allowing for process optimization under more industrially relevant conditions. The performance of the electrowinning processes was evaluated by varying different parameters such as pH, metal-ion concentration, temperature, current density and cathode material. Some experiments were also conducted in state-of-the-art sulfate-based electrolytes for comparison. Overall, the results provide insight on how to optimize the process parameters for metal electrowinning from MSA-based electrolytes to obtain high-purity metals at as low energy consumption as possible.
This work was supported by the European Union’s Framework Programme for research and innovation Horizon Europe, via project CICERO [Grant number 101137560]