Optimized ore processing using molten salts for leaching and thermal energy source

Abstract

A method for the electrolytic production of pure copper from copper-containing compounds dissolved in a high-temperature bath of molten salts which function as an electrolyte in an electrolytic cell. An electric current is passed between an anode immersed in the copper-ion rich molten salt bath and a cathode or cathode-lined kettle in which the molten salt bath is contained, thereby reducing the dissolved copper ions to form pure molten copper. The deposited molten copper collects at the bottom of the kettle and can be separated from the molten salt bath using conventional means.

1 . A method of producing pure metallic copper in an electrolytic cell containing a molten salt electrolyte, the method comprising the steps of:
 providing a vessel for containing the molten salt electrolyte at a temperature of between 500° C. and 1200° C., said vessel comprising a bottom and walls extending upwardly from said bottom, wherein said vessel further comprises an outlet configured as a drain;   providing at least one copper-containing compound;   dissolving said at least one copper-containing compound in said molten salt electrolyte;   providing at least one anode in liquid communication with said molten salt electrolyte;   providing at least one cathode in communication with said vessel bottom;   passing an electrical current through said anode and said cathode, thereby depositing molten copper at said cathode and producing gas at said anode;   removing copper deposited at said cathode through the outlet in said vessel.   
     
     
         2 . The method of  claim 1 , wherein said vessel further comprises a mechanical stirrer configured to aerate said molten salt electrolyte and any copper copper-containing compounds dissolved therein. 
     
     
         3 . The method of  claim 1 , wherein said vessel is composed of fused quartz. 
     
     
         4 . The method of  claim 1 , wherein said anode and said cathode are composed of graphite carbon. 
     
     
         5 . The method of  claim 1 , wherein said electrolyte comprises at least one compound selected from the group consisting of the halide salts of alkali metals, alkaline earth metals, and magnesium. 
     
     
         6 . The method of  claim 1 , further comprising the step of monitoring the electric potential of the molten salt electrolyte using a reference electrode. 
     
     
         7 . A method of producing pure metals from slag obtained from the copper mining process using an electrolytic cell containing a molten salt electrolyte, the method comprising the steps of:
 providing an extraction vessel for containing a mixture of molten salt electrolyte and slag at a temperature of between 1000° C. and 1200° C., wherein said extraction vessel comprises a bottom and walls extending upwardly from said bottom and is configured with a mechanical stirrer to aerate the mixture of slag and molten salt electrolyte contained in the extraction vessel, thereby causing metal ions in the slag to be dissolved as metal ions in the electrolyte;   wetting said slag in said molten salt electrolyte in said extraction vessel;   removing metal ion-depleted slag from said extraction vessel;   transferring metal ion-rich electrolyte from said extraction vessel to said electrodeposition vessel;   providing an electrodeposition vessel in liquid communication with said extraction vessel, said electrodeposition vessel comprising:
 a bottom and walls extending upwardly from said bottom, and further comprising an outlet configured as a drain; 
 at least one anode; 
 at least one cathode in communication with said vessel bottom in said electrodeposition vessel; 
   passing electrical current through said anode and said cathode in said electrodeposition vessel, thereby depositing molten metal at said cathode and producing gas at said anode;   removing metal deposited at said cathode through the outlet in said vessel.   
     
     
         8 . The method of  claim 7 , wherein said vessel further comprises a mechanical stirrer configured to aerate said molten salt electrolyte and any copper copper-containing compounds dissolved therein. 
     
     
         9 . The method of  claim 7 , wherein said vessel is composed of fused quartz. 
     
     
         10 . The method of  claim 7 , wherein said anode and said cathode are composed of graphite carbon. 
     
     
         11 . The method of  claim 7 , wherein said electrolyte comprises at least one compound selected from the group consisting of the halide salts of alkali metals, alkaline earth metals, and magnesium. 
     
     
         12 . The method of  claim 7 , further comprising the step of monitoring the electric potential of the molten salt electrolyte using a reference electrode. 
     
     
         13 . An electrolytic cell for the production of pure copper metal, the electrolytic cell comprising:
 a molten salt electrolyte having at least one copper-containing compound dissolved in therein;   a vessel for containing the molten salt electrolyte at a temperature of between 500° C. and 1200° C., said vessel comprising a bottom and walls extending upwardly from said bottom, wherein said vessel further comprises an outlet configured as a drain;   at least one anode in liquid communication with said molten salt electrolyte;   at least one cathode in communication with said vessel bottom;   a source of electrical current in communication with said anode and said cathode.   
     
     
         14 . The electrolytic cell of  claim 13 , further comprising a reference electrode for monitoring the electric potential of the molten salt electrolyte. 
     
     
         15 . The electrolytic cell of  claim 13 , wherein said vessel further comprises a mechanical stirrer configured to aerate said molten salt electrolyte and any copper copper-containing compounds dissolved therein. 
     
     
         16 . The method of  claim 13 , wherein said vessel is composed of fused quartz. 
     
     
         17 . The method of  claim 13 , wherein said anode and said cathode are composed of graphite carbon. 
     
     
         18 . The method of  claim 13 , wherein said electrolyte comprises at least one compound selected from the group consisting of the halide salts of alkali metals, alkaline earth metals, and magnesium.