| abstract |
A cyclic process for selective recovery of a metal from a material which contains other metal values in addition to the selected metal, comprises leaching the material with an aqueous solution capable of leaching metal values including the selected metal from the material. The resulting, aqueous solution, containing the selected metal and other metallic contaminants, is dispersed in an organic medium comprising an exchange reagent which is capable of selectively extracting the selected metal from the aqueous solution while rejecting any other metal values in the aqueous solution. The dispersion, comprising the aqueous solution and the organic medium containing the extracted metal, is passed as a flowing stream through a zone in which there are a plurality of spaced, parallel, elongate electrodes. Flow of the dispersion is such that it is distributed uniformly about the electrodes. An alternating current potential is applied to the electrodes to create an A.C. electrical field within the zone sufficient to electrically coalesce the aqueous phase of the flowing dispersion, and the aqueous phase is then separated from the organic phase in a separation zone downstream from the electrodes. The selected metal values are stripped from the organic phase by dispersing the organic phase in an aqueous stripping solution. This dispersion is then resolved into an organic phase and an aqueous phase by flowing the dispersion through a zone as is described above. The selected metal is recovered in essentially pure form from the aqueous phase, and the organic phase can be used in further selective extraction of metal values from aqueous leach solution. |