Kinetics of Cu(II) cementation on a pure aluminum disc in acidic sulphate solutions

Abstract

Abstract The rates of copper cementation on pure aluminum discs were studied as a function of (a) initial copper ion concentration, (b) temperature, (c) initial hydrogen ion concentration, and (d) the effect of the peripheral velocity of the Al disc.At low initial copper ion concentration (1 × 10−4M), there are two rate-controlling processes: ionic diffusion control at temperatures. above 40°C, and surface reaction control at temperatures below 40° C. At higher initial copper ion concentrations (5 × 10−3 M), the rate is controlled by a chemical (surface) reaction.When the-hydrogen ion concentration is increased to 0.7 M, the cementation rate increases. The pH remains constant during the reaction.The cemented deposit is pure copper. The structure. of the deposit is dependent on both temperature and the initial copper ion concentration. At high initial copper ion concentration (5 × 10-3 M) and at high temperatures (75° C), the rate, which was constant initially, increases with increasing deposition. Resume ...