Metal production from halide-based molten salt electrolysis process

Abstract

An electrolysis reactor for electrolytically generating one or more metal cathode product(s) includes a dimensionally stable anode (DSA) and a cathode positioned in a molten salt electrolyte containing fused salts, wherein the DSA includes a graphite substrate and a non-ceramic, transition metal oxide coating on the substrate and wherein during electrolysis the one or more metal cathode product(s) are produced at the cathode.

Having described the invention, the following is claimed: 
     
         1 . An electrolysis reactor for electrolytically generating one or more metal cathode product(s) comprising:
 a dimensionally stable anode (DSA) and a cathode positioned in a molten salt electrolyte containing fused salts, wherein the DSA includes a graphite substrate and a non-ceramic, transition metal oxide coating on the substrate and wherein during electrolysis the one or more metal cathode product(s) are produced at the cathode.   
     
     
         2 . The electrolysis reactor of  claim 1 , wherein the non-ceramic, transition metal oxide coating includes RuO 2 , IrO 2 , Fe 2 O 3 , NiO, Cr 2 O 3 , Mn 2 O 3 , CuO, or binary mixtures thereof. 
     
     
         3 . The electrolysis reactor of  claim 1 , wherein the non-ceramic, transition metal oxide coating includes a 30:70 wt. % to 60:40 wt. % binary mixture of two of RuO 2 , IrO 2 , Fe 2 O 3 , NiO, Cr 2 O 3 , Mn 2 O 3 , or CuO. 
     
     
         4 . The electrolysis reactor of  claim 1 , the non-ceramic, transition metal oxide coating has a thickness of about 1 μm to about 1000 μm. 
     
     
         5 . The electrolysis reactor of  claim 1 , wherein the molten salt electrolyte includes a molten mixture of at least 50 mol % chloride containing fused salts. 
     
     
         6 . The electrolysis reactor of  claim 5 , wherein balance of the fused salt comprises a single electrolyte or mixture of electrolytes where the anion is a carbonate, sulfate, phosphate, fluoride, bromide, iodide, or hydroxide. 
     
     
         7 . The electrolysis reactor of  claim 5 , wherein the molten salt electrolyte includes a metal salt of the one or more metal cathode product(s), the one or metal cathode product(s) including at least one of Fe, Al, Mg, Ti, Li, Na, Dy, Nd, NdPr, La, or Ce. 
     
     
         8 . The electrochemical cell electrolysis reactor of  claim 7 , wherein the metal salt includes at least one of FeX 2 , FeX 3 , AlX 3 , NdX 3 , MgX 2 , TiX 3 , TiX 4 , LiX, NaX, DyX 2 , DyX 3 , NdPrX 6 , LaX 3 , CeX 2 , or CeX 3 , where X is a halogen. 
     
     
         9 . The electrolysis reactor of  claim 8 , wherein the molten salt electrolyte includes a eutectic of the metal salt and at least one of LiCl, KCl, NaCl, CsCl, MgCl 2 , BaCl 2 , SrCl 2 , or CaCl 2  and the molten salt electrolysis is conducted at a temperature of about 400° C. to about 1200° C. 
     
     
         10 . The electrolysis reactor of  claim 8 , wherein the molten salt electrolyte includes a eutectic of FeX 2  and/or FeX 3 , where X is a halogen, and at least one of LiCl, KCl, NaCl, CsCl, MgCl 2 , BaCl 2 , SrCl 2 , or CaCl 2  and the molten salt electrolysis is conducted at a temperature of about 400° C. to about 1200° C. 
     
     
         11 . The electrolysis reactor of  claim 1 , wherein electrolysis is conducted at a current density of about 50 mA/cm 2  to about 10 A/cm 2 . 
     
     
         12 . A system for production of iron from iron oxides and/or iron ore containing iron compounds and/or aqueous spent pickle liquor containing iron halide, the system comprising:
 an electrolysis reactor for molten salt electrolysis of iron halide feedstock to iron and halogen(s), wherein the electrolysis reactor includes a dimensionally stable anode (DSA) and a cathode positioned in a molten salt electrolyte containing fused salts, the DSA includes a graphite substrate and a non-ceramic, transition metal oxide coating on the substrate, and during electrolysis iron is produced at the cathode from the iron halide feed stock and halogen gas is produced at the anode.   
     
     
         13 . The system of  claim 12 , wherein the non-ceramic, transition metal oxide coating includes RuO 2 , IrO 2 , Fe 2 O 3 , NiO, Cr 2 O 3 , Mn 2 O 3 , CuO, or binary mixtures thereof. 
     
     
         14 . The system of  claim 12 , wherein the non-ceramic, transition metal oxide coating includes a 30:70 wt. % to 60:40 wt. % binary mixture of two of RuO 2 , IrO 2 , Fe 2 O 3 , NiO, Cr 2 O 3 , Mn 2 O 3 , or CuO. 
     
     
         15 . The system of  claim 12 , wherein the molten salt electrolyte includes a molten mixture of at least 50 mol % chloride containing fused salts. 
     
     
         16 . The system of  claim 12 , wherein the molten salt electrolyte includes a eutectic of FeX 2  and/or FeX 3 , where X is a halogen, and at least one of LiCl, KCl, NaCl, CsCl, MgCl 2 , BaCl 2 , SrCl 2 , or CaCl 2  and the molten salt electrolysis is conducted at a temperature of about 400° C. to about 1200° C. 
     
     
         17 . The system of  claim 12 , wherein electrolysis is conducted at a current density of about 50 mA/cm 2  to about 10 A/cm 2 . 
     
     
         18 . The system of  claim 12 , further comprising a halogenation reactor configured for non-carbothermic reacting of the iron oxides and/or iron ore containing iron compounds with halogen acids to form the iron halide feedstock and/or a dehydration reactor for dehydrating an aqueous spent pickle liquor containing iron halide to form the iron halide feedstock. 
     
     
         19 . The system of  claim 18 , where the halogenation reactor includes a halogen acid or leaching acid converted from the generated halogen at molarity effective to convert the iron oxide to the iron halide feedstock. 
     
     
         20 . The system of  claim 18 , wherein the iron ore comprises at least one of taconite, hematite, siderite, ironstone, magnetite ore, limonite, or goethite; and/or
 the aqueous spent pickle liquor comprises a product from a pickling bath used in the production of steel.