Cyclic process using A.C. for selective recovery of metals from materials containing same

Claim 1

A cyclic process for selectively recovering metals from a material containing other metallic values in addition to the selected metal, comprising (a) leaching said material with an aqueous leach solution; (b) recovering a pregnant, aqueous, leach solution containing the selected metal and other metallic contaminants dissolved therein; (c) intimately mixing the recovered aqueous leach solution with an organic medium containing an exchange reagent, which is capable of selectively extracting the selected metal from the aqueous solution, thereby producing a dispersion comprising an aqueous portion containing said other metallic and exchanged ions, and an organic portion containing the exchange reagent and the selected metal values; (d) passing the dispersion from step (c) through a flow way having a plurality of spaced, parallel, elongate electrodes disposed therein so that the flow of dispersion in the flow way is distributed uniformly about the elongate electrodes; (e) subjecting the flow of dispersion in step (d) to an A.C. electric field by applying an A.C. potential to the elongate electrodes in the flow way, said field being sufficient to electrically coalesce the aqueous phase of the dispersion as it flows through said flow way; (f) feeding the electrically treated dispersion from step (e) to a gravity settling tank wherein the coalesced aqueous phase is separated from the organic phase; (g) recycling the aqueous phase as leach solution for further leaching of said material; (h) intimately mixing the organic phase from step (f) with an aqueous stripping solution which is capable of stripping the selected metal ions from the organic phase, thereby producing a second dispersion comprising an aqueous portion containing the selected metal and an organic portion containing the exchange reagent; (i) passing the dispersion from step (h) through a second flow way having a plurality of spaced, parallel elongate electrodes disposed therein so that the flow of dispersion in said second flow way is distributed uniformly about the elongate electrodes; (j) subjecting the flow of dispersion in step (i) to an A.C. electric field by applying an A.C. potential to the electrodes in said second flow way, said field being sufficient to electrically coalesce the aqueous phase of the dispersion as it flows through second flow way; (k) feeding the electrically treated dispersion from step (j) to a gravity settling tank wherein the coalesced, aqueous phase which contains the selected metal values is separated from the organic phase which contains the exchange reagent; (1) recycling the organic phase from step (k) as the organic medium containing an exchange reagent to be mixed with further leach solution in step (c); and (m) recovering the selected metal values from the aqueous phase obtained in step (k).