Removal and Recovery of Copper and Zinc by Supported Liquid Membranes with Strip Dispersion

Abstract

We have developed and scaled up effective supported liquid membrane (SLM) systems with strip dispersion for the selective removal and recovery of copper and zinc from he Berkeley Pit water containing about 150 ppm copper, 550 ppm zinc, and other metals. The stability of the SLM has been ensured by an improved SLM with strip dispersion, where the aqueous strip solution is dispersed in the organic membrane solution in a mixer. The strip dispersion formed is circulated from the mixer to the membrane module to have a constant supply of the organic solution to the membrane pores. The copper SLM system using nonylsalicyl aldoxime and ketoxime not only removed removed the copper to less than 0.1 ppm in the treated feed allowable for discharge or reuse, but also recovered the copper at a high concentration of greater than 10,000 ppm in the strip solution suitable for resale or reuse. For he zinc SLM system with di(2,4,4-trimethylpentyl) dithiophosphinic acid, the zinc was removed to less than 0.3 ppm in the treated feed while a high zinc concentration of more than 17,000 ppm was recovered in the strip solution. The scale-up results from pilot runs agreed reasonably well with the laboratory results. Both the copper and zinc concentrations in the treated feed met the target specifications for discharge whereas both the strip solutions recovered ad high purity for reuse. Thus, the goals of zero discharge and no sludge have been achievable.