Coupled transport membranes for metal separations. Final report on phase 3, May 1975-May 1978

The report covers Phase III of a continuing program to apply a new membrane process--coupled transport--to the separation and concentration of copper and uranium from hydrometallurgical leach solutions. During Phases I and II of this program, the basic feasibility and economic viability of the process was demonstrated with laboratory cells and with copper leach solutions. During this third phase, small bench-scale membrane separation units were constructed, consisting of three to four hollow fiber modules with a total surface area of up to 100 sq ft. These units were used to define the process system parameters for copper recovery. During the course of these studies, mechanical problems with the hollow fiber membrane modules surfaced which delayed completion of the module stability and field trial portion of the program. In all other aspects, the units worked well, yielding high concentration and moderate separation factors and good fluxes. The technical feasibility of separating and concentrating uranium from leach liquors using tertiary amine agents was also demonstrated. High concentration and separation factors resulted at fluxes that appear to make coupled transport membranes for uranium separations competitive with existing techniques