Study on the dissolution process of zinc anode in ammoniacal ammonium chloride system

To evaluate the feasibility of ammoniacal ammonium chloride system (NH3–NH4Cl) served as the electrolyte for the electrorefining process of zinc slag. The zinc anodeʹs dissolution process in the NH3–NH4Cl solution was studied through electrochemical test, meanwhile, the effects of each component concentration of the NH3–NH4Cl electrolyte on the dissolution potential of zinc anode were investigated. The results suggested that zinc anode mainly took place active dissolution in the NH3–NH4Cl system, the apparent activation energy was 14.46 kJ mol− 1 and the exchange current density 1.48 × 10− 4 A cm− 2. The increment of the NH4Cl concentration made a little contribution on decreasing the dissolution potential of zinc anode. However, the increment of NH3 concentration exhibited a notable effect on decreasing the dissolution potential of zinc anode. The anodic dissolution potential moved to positive-direction with the increase of Zn2+ concentration in the NH3–NH4Cl system.