Use of Continuous Ion Exchange For Removal of Environmental Contaminants From Waste Streams

CIM Bulletin, Vol. 71, No. 796, 1978

M. J. Slater, Professor, School of Chemical Engineering, University of Bradford, Bradford, Yorkshire, U.K., B. H. Lucas, Assistant Head, and G. M. Ritcey, Head, Hydrometallurgy Section, OPL, MSL, Canada Centre for Mineral and Energy Technology, Department of Energy, Mines and Resources, Ottawa, Canada

Ion exchange using resins is one of the few processes capable of reducing ionic contaminants in effluents to very low levels. Continuous fluidized-bed ion exchange is an advantageous technique for processing dirty effluents and thin slurries. It also reduces resin inventory and equipment cost compared to fixed packed beds. A simple continuous fluidized-bed unit has been investigated for treating effluents and its performance is described. Breakthrough curves were first obtained from static fluid-ized fixed beds; these data were then used to determine the required operating conditions for a periodic-flow, counter-current fluidized-bed ion exchange system. A waste stream, containing about 56 ppm copper, was treated in the continuous system using an extraction fluidized bed depth of 203 cm and a flow rate of 1.22 cm3/cm2s (900 gph/sq.ft) to yield an effluent containing less than 0.02 ppm copper. A generalized design method is proposed for similar chemical systems.
Keywords: Hydrometallurgy, Ion exchange, Environmental control, Waste water, Resins, Fluidized beds, Mixing cells, Extraction columns, Effluents.