Electrolytic cell for production of rare earth metals

Abstract

An electrolytic cell for production of rare earth metals is disclosed. The electrolytic cell includes a cell housing provided with one or more inclined channels disposed in a floor of the cell housing along which channel(s) molten rare earth metals produced in the electrolytic cell can drain. One or more cathodes are suspended within the cell housing in substantially vertical alignment with the one or more channels. Respective opposing surfaces of the one or more cathodes are downwardly and outwardly inclined at an angle from the vertical. One or more pairs of anodes are suspended within the cell housing; each anode in the one or more pairs has a facing surface inclined from the vertical and spaced apart in parallel alignment with respective opposing inclined surfaces of the one or more cathodes to define a substantially constant anode-cathode distance therebetween. The electrolytic cell also includes a sump for receiving molten rare earth metals from the channel, wherein the sump is spaced apart and isolated from the one or more cathodes and the one or more anodes. Separation of the molten rare earth metals from the cathode(s) and the anode(s) prevents reaction and/or contamination with fugitive carbon arising from the anode(s) or back reaction with off gases.

1 - 17 . (canceled) 
     
     
         18 . An electrolytic cell for production of rare earth metals comprising:
 a cell housing provided with one or more inclined channels disposed in a floor of the cell housing along which channel(s) molten rare earth metals produced in the electrolytic cell can drain;   one or more cathodes suspended within the cell housing in substantially vertical alignment with the one or more channels, respective opposing surfaces of the one or more cathodes being downwardly and outwardly inclined at an angle from the vertical;   one or more pairs of anodes suspended within the cell housing, each anode in the one or more pairs having a facing surface inclined from the vertical and spaced apart in parallel alignment with respective opposing inclined surfaces of the one or more cathodes to define a substantially constant anode-cathode distance therebetween; and,   a sump for receiving molten rare earth metals from the channel, wherein the sump is spaced apart and isolated from the one or more cathodes and the one or more anodes.   
     
     
         19 . The electrolytic cell as defined in  claim 18  further comprising a displacement device to control a height of the electrolyte bath contained in the cell housing. 
     
     
         20 . The electrolytic cell as defined in  claim 18  further comprising a device operatively associated with the one or more anodes to control a distance between the anodes and the opposing sides of the cathode in response to anode consumption. 
     
     
         21 . The electrolytic cell as defined in  claim 19 , wherein displacement device comprises an inert body which is suspended in the housing and positionable in a vertical direction. 
     
     
         22 . The electrolytic cell as defined in  claim 20 , wherein the device operatively associated with the one or more anodes comprises a horizontal positioning apparatus. 
     
     
         23 . The electrolytic cell as defined in  claim 22 , wherein the horizontal positioning apparatus is configured, in use, to laterally translate the one or more anodes towards the cathode in response to a rate at which the anodes are consumed. 
     
     
         24 . The electrolytic cell as defined in  claim 18 , wherein the one or more channels therein are inclined from the horizontal at an angle of up to about 10°. 
     
     
         25 . The electrolytic cell as defined in  claim 18 , wherein the one or more channels have a cross-sectional shape that is rectangular, V-shaped or U-shaped. 
     
     
         26 . The electrolytic cell as defined in  claim 18 , wherein the opposing sides of the cathode and the facing sides of the anode are inclined from the vertical by up to 45°. 
     
     
         27 . The electrolytic cell as defined in  claim 26 , wherein the opposing sides of the cathode and the facing sides of the anode are inclined from the vertical by 2° to 10°. 
     
     
         28 . A system for electrolytically producing rare earth metals comprising:
 an electrolytic cell as defined in  claim 18 ;   a feed material comprising one or more rare earth metal compounds capable of undergoing electrolysis to produce rare earth metals;   a molten electrolyte in which the feed material is soluble; and,   a source of direct current configured to pass a current between an anode and a cathode in the electrolytic cell to electrolyse the feed material and thereby produce molten rare earth metal product in the electrolytic cell.   
     
     
         29 . A process for electrolytically producing rare earth metals comprising:
 providing an electrolytic cell as defined in  claim 19 ;   charging the electrolytic cell with a feed material comprising one or more rare earth metal compounds capable of undergoing electrolysis to produce rare earth metals and an electrolyte bath comprising molten electrolyte in which the feed material is soluble;   passing a direct current between at least one consumable anode and a cathode in the electrolytic cell to electrolyse the feed material and thereby produce molten rare earth metal product on the cathode; and,   displacing the molten electrolyte in the electrolytic cell to maintain a height of the electrolyte bath in the electrolytic cell.   
     
     
         30 . A process for electrolytically producing rare earth metals comprising:
 providing an electrolytic cell according to  claim 20 ;   charging the electrolytic cell with a feed material comprising one or more rare earth metal compounds capable of undergoing electrolysis to produce rare earth metals and a molten electrolyte in which the feed material is soluble;   passing a direct current between at least one consumable anode and a cathode in the electrolytic cell to electrolyse the feed material and thereby produce molten rare earth metal product on the cathode; and,   translating the or each consumable anode toward the cathode in response to a rate of anode consumption to maintain a constant cathode-anode distance in the electrolytic cell.