Abstract: An apparatus and method for electrowinning metal from ionic solutions is provided wherein ionic solution is subject to nanofiltration. An electrowinning cell (10) includes a reservoir (12) adapted to receive an ionic solution (14). During operation, metal ions in solution (14) electroplate onto cathode (18). Nanofilter (20) is in fluid communication with the reservoir and receives solution (14) from a location (22) proximate to the cathode (18). Retentate (52) is formed as a first portion (26) of the solution (14) which passes through the membrane (21) of the filter (20). Permeate (54) is formed as a second portion (28) of the solution (14) which passes through the membrane (21) of the filter (20) to a second region (29) on the opposite side of membrane (21) from the first region (27). Permeate (54) has a second concentration of metal ions lower than the first concentration in first portion (26). Retentate (52) is returned to the reservoir (12) to intermix with solution (14).

Abstract: The present invention relates to an electrowinning cell adapted to recover metal ions from a solution as their corresponding elementary metals. The electrowinning cell includes a reservoir and a filter in fluid communication with the reservoir. The filter is operative to receive a solution containing metal ions from a location proximate to the cathode and to retain a first portion of the solution having a first concentration of metal ions and to remove a second portion of the solution having a second concentration of metal ions lower than the first concentration. The electrowinning cell additionally includes return means operative to return the first portion of the solution to the reservoir. The present invention also relates to a method of concentrating metal ions in a solution for use in an electrochemical cell and to a system for reducing metal ions in a solution to their corresponding elementary metals.

Abstract: Wastewater discharge, which is generated in an ion exchange regeneration system having a cation exchange bed and an anion exchange bed, is minimized by circulating a displacement rinse through a cation exchange bed, saving an effluent of the displacement rinse to be used as a regenerant solution in a subsequent cycle, circulating the remaining rinse in the cation exchange bed through an anion exchange bed that has been exhausted by service flow, circulating a displacement rinse through the anion exchange bed, and circulating a final rinse through the cation and anion exchange beds. The volume of wastewater discharge can be reduced to a degree of approximately 80-90% of a typical conventional system, i.e., waste water discharge can be reduced to 1-2 bed volumes. Storage tanks, automation valves, etc. can be eliminated while high reduction of wastewater discharge is effected.