Production of copper powder from synthetic wastewaters by cementation on a longitudinal finned rotating zinc cylinder

摘要

This study aims to the enhancement of Cu2+ ions removal from wastewaters and recovery of the metal value by cementation on a longitudinal finned rotating zinc cylinder. The effect of different parameters such as cylinder rotational speed (rpm), initial Cu2+ ions concentration and the effect of the fin height to cylinder diameter (e/d) on the rate of Cu2+ ions cementation was investigated. In addition, the effect of drag reducing polymer on the rate of Cu2+ cementation was examined. The rate of cementation was expressed in terms of the mass transfer coefficient. The results revealed that the mass transfer coefficient increases with increasing rpm, initial Cu2+ concentration and e/d ratio. The present results show that finned rotating cylinder enhances rate of cementation compared to smooth rotating cylinder by percentage ranges from 28.79 to 134.85 depending on the operating conditions. On the other hand, the presence of drag reducing polymer retards the rate of cementation. The present data fit the following dimensionless equations: For smooth cylinder: Sh=0.74 Re-0.69 Sc-0.33. For finned rotating cylinder: Sh=0.38 Re-0.9 Sc-0.33 (e/d)(0.25). The importance of the above correlations in the design and operation of industrial-scale rotating cylinders cementation reactors was pointed out.