Electrochemical removal of Cu, Fe and Mn from molten ZnCl2:KCl:NaCl

This study was carried out to investigate the use of electrodeposition for the removal of impurities from molten ZnCl2:KCl:NaCl in order to purify and reuse the molten salt after electrorefining and electrowinning. The deposition of the elements, Cu, Fe, and Mn from CuCl, FeCl2, FeCl3, and MnO2 in molten salt at 260 ℃ was examined using cyclic voltammetry (CV), employing graphite and platinum (Pt) electrodes. Subsequently, a series of potentiostatic electrolysis experiments were conducted to remove the impurities in the salt using a zinc (Zn) electrode. X-ray diffraction (XRD) was used in one case to analyze and confirm that the reduced element was deposited on the surface of the Zn electrode. The results show that Cu and Fe(III) were removed from the molten salt through 1.5 and 2.5 h of electrodeposition, respectively. The results for removing Fe(II) and Mn were slightly different after 3 h of purification, despite being mostly effectively separated, there were still some impurities found in the molten salt.