Abstract:The effects of temperature, nickel concentration and current density on the current efficiency and the electrolyzer voltage were investigated in the process of electrowinning nickel. The results show that the current efficiency is above 90% under the various experimental conditions, and the electrolyzer voltage is less than that of traditional electrolyzer system. Therefore, the optimized parameters, i.e. temperature of 50℃, current density of 400A/m², are determined. It is also elucidated that anodic product is high valent nickel compound in the process of electrodeposition in terms of X-ray diffraction and chemical analysis. The amount of solid product formed on the electrode surface decreases with an increase in ammonium chloride concentration by cyclic voltammetry analysis. It is also indicated that the anodic gas species are mainly composed of nitrogen by vapor phase chromatograph.

Key words:  nickel; electrodeposition; ammonia coordinate