Copper removal from effluents by various separation techniques

In this study, the recovery of copper ions from simulated and real wastewaters of a mine and minerals processing plant was investigated. The separation process employed was flotation, which was applied in three different mechanisms: (i) ion flotation using xanthates, (ii) precipitate flotation generating copper hydroxide and (iii) sorptive flotation using zeolites as sorbent material. Under the studied conditions, ion and sorptive flotation were found to be effective methods for copper removal with almost 100% Cu removal achieved, while the precipitation method failed. The copper removal was always higher in simulated mixture than in real effluents; it may be due to the presence of other minor constituents that they have not taken into account in simulated mixture (e.g. organic compounds). The bubble generation method was that of dispersed-air flotation. Reference is also given to economic aspects. An economic study of sorptive flotation showed that the capital investment for a 10 m(3) /h plant would be of the order of US$1.15 million dollars. The operating costs are about US$1.76 million per year. The total revenues from water recycling and reuse are US$68,800 per annum, without calculating the benefits of copper recovery. (C) 2004 Elsevier B.V. All rights reserved.