A New Approach for Cu and Fe/Fe _xB Production from Chalcopyrite by Molten Salt Electrolysis

Abstract: In the present study, copper (Cu) and iron boride (Fe_xB) were produced for the first time through molten salt electrolysis using chalcopyrite (CuFeS₂) in an oxide-based borax electrolyte. Molten salt electrolysis was carried out at 1073 K and a current density of 600 mA/cm² for 3600 s under galvanostatic conditions. Cu and Fe/Fe_xB were deposited on the graphite crucible surface used as the cathode. The particles obtained as a result of electrolysis were examined by X-ray diffraction (XRD) and determined to contain Cu and Fe/Fe_xB. The location and ratio of Cu and Fe_xB in the particles were investigated by using EDS mapping, energy-dispersive spectroscopy (EDS), and X-ray spectroscopy (XRD); Cu and Fe/Fe_xB were found to be present throughout the particles at different ratios. Cu and Fe/Fe_xB were successfully separated from each other by selective leaching of copper in a 1 M NH₃–H₂O solution. The time-dependent dissolution behavior of Cu was investigated at pH 8, 298 K, 600 rpm stirring rate for 900–5400 s, and it was observed that the dissolution rate increased over time and all the copper had completely dissolved after 5400 s. After leaching particles were examined by XRD and SEM, it was revealed that Fe/Fe_xB particles did not contain any Cu. Graphical Abstract: [Figure not available: see fulltext.]