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

Abstract

In the present study, copper (Cu) and iron boride (FexB) 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/FexB 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/FexB. The location and ratio of Cu and FexB in the particles were investigated by using EDS mapping, energy-dispersive spectroscopy (EDS), and X-ray spectroscopy (XRD); Cu and Fe/FexB were found to be present throughout the particles at different ratios. Cu and Fe/FexB 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/FexB particles did not contain any Cu.