Solidifying metals or metalloids from a liquid cathode during molten oxide electrolysis

Abstract

A method and system for precipitating a solid using molten oxide electrolysis are presented. Using an electrical current for electrolysis in a first vessel, an oxide material is heated to form a liquid cathode. The first vessel also includes a corresponding anode. A portion of the liquid cathode is received into a second vessel that is separated from the first vessel by a conduit. The portion of the liquid cathode is allowed to cool. Precipitate of the cooled liquid cathode may then be collected in the second vessel. The precipitate may be a metal or metalloid, such as silicon. The method and system allow for continuous processing for production of a precipitate material, in contrast to batch processing of other methods or systems. For example, precipitate may be harvested from the second vessel while electrolysis is continuously performed in the first vessel.

We claim as follows: 
     
         1 . A method for precipitating a solid using molten oxide electrolysis, the method comprising:
 via an electrical current, producing electrolysis in a first vessel containing a melted oxide material that includes a liquid cathode;   receiving a portion of the liquid cathode into a second vessel that is separated from the first vessel via a conduit, which conveys the portion of the liquid cathode from the first vessel;   allowing the portion of the liquid cathode to cool; and   collecting a precipitate of the cooled liquid cathode in the second vessel.   
     
     
         2 . The method of  claim 1 , wherein the precipitate of the cooled liquid cathode is a metal or metalloid. 
     
     
         3 . The method of  claim 2 , wherein the metalloid is silicon. 
     
     
         4 . The method of  claim 1 , wherein the oxide material is a mixture of two or more metallic oxides. 
     
     
         5 . The method of  claim 1 , wherein allowing the portion of the liquid cathode to cool comprises at least partially controlling heat transfer of the flow of the portion of the liquid cathode in the conduit or the second vessel. 
     
     
         6 . The method of  claim 1 , further comprising controlling the temperature of the portion of the liquid cathode in the second vessel to produce a vertical thermal gradient. 
     
     
         7 . The method of  claim 1 , wherein collecting the precipitate of the cooled liquid cathode in the second vessel is performed while simultaneously performing the electrolysis in a first vessel. 
     
     
         8 . The method of  claim 1 , wherein collecting the precipitate of the cooled liquid cathode comprises collecting the precipitate on a seed crystal. 
     
     
         9 . The method of  claim 1 , wherein collecting the precipitate of the cooled liquid cathode in the second vessel is performed without removing the liquid cathode that is in the first vessel. 
     
     
         10 . The method of  claim 1 , wherein the liquid cathode, based on density of the liquid cathode compared to density of the oxide material, collects at a bottom region of the first vessel and in contact with a cathodic electrode of the electrolysis. 
     
     
         11 . The method of  claim 1 , further comprising collecting oxygen gas from the first vessel while simultaneously collecting the precipitate in the second vessel. 
     
     
         12 . A molten oxide electrolysis (MOE) system comprising:
 a first vessel that includes i) an anode and ii) a cathodic electrode in a bottom region of the first vessel, wherein
 the cathodic electrode is configured to be in electrical communication with an oxide material in the first vessel, 
 the anode and the cathodic electrode are configured to provide an electrical current therebetween for a process of electrolysis of the oxide material, and 
 the process of electrolysis of the oxide material produces a liquid cathode; and 
   a second vessel that is separated from the first vessel by a conduit for carrying a portion of the liquid cathode from the first vessel to the second vessel, the second vessel including a precipitating surface configured to be immersed in the portion of the liquid cathode and to collect a precipitate of the cooled liquid cathode.   
     
     
         13 . The MOE system of  claim 12 , wherein the precipitate of the cooled liquid cathode is a metal or metalloid. 
     
     
         14 . The MOE system of  claim 12 , wherein the oxide material is derived from lunar regolith. 
     
     
         15 . The MOE system of  claim 12 , further comprising a temperature controller to control the temperature of the portion of the liquid cathode that is in the second vessel or the conduit. 
     
     
         16 . The MOE system of  claim 15 , wherein the temperature controller is configured to control the temperature of the portion of the liquid cathode in the second vessel to produce a vertical thermal gradient. 
     
     
         17 . The MOE system of  claim 16 , further comprising a seed holder configured to raise or lower the precipitating surface based, at least in part, on the vertical thermal gradient. 
     
     
         18 . The MOE system of  claim 12 , further comprising a system controller to enable the MOE system to collect the precipitate of the cooled liquid cathode in the second vessel while simultaneously performing the electrolysis in a first vessel. 
     
     
         19 . The MOE system of  claim 18 , wherein the system controller further enables the MOE system to collect the precipitate of the cooled liquid cathode in the second vessel without removing the liquid cathode that is in the first vessel. 
     
     
         20 . The MOE system of  claim 12 , wherein the liquid cathode is a liquid metal cathode.