Method and apparatus for recovering metals and sulfur from feed streams containing metal sulfides and polysulfides

A system for recovering metal and elemental Sulfur from a non-aqueous feed stream, comprising:

• a first electrolytic cell comprising:
• a first anolyte compartment configured to hold an anolyte, wherein the anolyte comprises at least one of an alkali metal sulfide and an alkali metal poly sulfide, a polar organic solvent that dissolves elemental Sulfur and dissolves at least one of the alkali metal sulfide and the alkali metal polysulfide, the anolyte further comprising at least one of a heavy metal, a heavy metal compound, and a heavy metal ion;
• a first anode positioned within the first anolyte compartment in communication with the anolyte;
• a first catholyte compartment configured to hold a catholyte, wherein the catholyte comprises an alkali ion-conductive liquid;
• a first cathode positioned within the first catholyte compartment in communication with the catholyte;
• a first separator positioned between the first anolyte compartment and the first catholyte compartment, the first separator in communication with the anolyte of the first anolyte compartment and the catholyte of the first catholyte compartment, the first separator configured to non-selectively transport cations;
• and
• a first power source in electrical communication with the first anode and the first cathode, wherein the first power source is configured to apply a voltage to the first electrolytic cell that is sufficient to reduce at least one heavy metal ion to heavy metal;
• and
• further comprising a second electrolytic cell in fluid communication with the first electrolytic cell, wherein the second electrolytic cell comprises:
• a second anolyte compartment configured to hold a anolyte, wherein the anolyte comprises at least one of an alkali metal sulfide and an alkali metal polysulfide, a polar organic solvent that dissolves elemental Sulfur and dissolves at least one of the alkali metal sulfide and the alkali metal poly sulfide, the anolyte of the second compartment further comprising at least a portion of anolyte removed from the first anolyte compartment of the first electrolytic cell;
• a second anode positioned within the second anolyte compartment m communication with the anolyte;
• a second catholyte compartment configured to hold a catholyte, wherein the catholyte comprises an alkali ion-conductive liquid;
• a second cathode positioned within the second catholyte compartment m communication with the catholyte;
• a second separator positioned between the second anolyte compartment and the second catholyte compartment, the second separator in communication with the anolyte of the second anolyte compartment and the catholyte of the second catholyte compartment, wherein the second separator is an alkali-ion selective membrane configured to selectively transport alkali ions;
• and
• a second power source in electrical communication with the second anode and the second cathode, wherein the second power source is configured to apply a voltage to the second electrolytic cell that is greater than the open circuit potential of the second electrolytic cell, wherein the second electrolytic cell is configured to separate and recover the alkali metal and elemental Sulfur.