Plasma process for metal production

Abstract

A plasma process for metal oxide reduction is disclosed herein. The process comprises producing a plasma to bring the metal oxide to a reaction temperature ranging from about 500°C to about 5000°C; and reacting the metal oxide at the reaction temperature ranging from about 500°C to about 5000°C with a reducing gas mixture comprising CO2 and a hydrocarbon to produce a reduced metal oxide. The reducing gas mixture comprises a CO2 / hydrocarbon ratio ranging from about 2:1 to about 1:4. The hydrocarbon is at least one of natural gas, CH4, C2H6, and C3H8.

Description

TITLE PLASMA PROCESS FOR METAL PRODUCTION CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application 63 / 602,018, filed November 22, 2023. The contents of the referenced application are incorporated into the present application by reference. BACKGROUND 1. Field

[0002] This disclosure relates to the fields of chemistry, pyrometallurgy and thermal plasma torches. More specifically, but not exclusively, the present disclosure broadly relates to the production of metals. Yet more specifically, the present disclosure relates to a process for the production of one or more metals from a feed material using a DC thermal plasma torch and a plasma gas comprising CO2and a hydrocarbon. The present disclosure also relates to pyrometallurgical applications using a DC thermal plasma torch and a plasma gas comprising CO2 and a hydrocarbon for treating feed materials comprising metals such as metal oxides. The present disclosure also relates to a leaching process for the recovery of the produced metal values. 2. Related Art

[0003] The following discussion of the background art is only intended to facilitate an understanding of the process described herein.

[0004] The chemical and physical properties of titanium make it a metal of great interest. It is widely used because of its strong heat resistance, low density, biocompatibility, and excellent corrosion resistance. Titanium has been used in a variety of industries such as the automobile, and aircraft industries. It has also found wide use in a variety of chemical and military applications, as well as for biomedical applications including the manufacture of implants and prostheses.

[0005] The Kroll method, one of the currently used industrial titanium refining methods, suffers from low production efficiency, and the production of titanium metal in the form of a porous sponge. In the Kroll method, titanium ore, the main component of which is titanium dioxide (TiO2), is reacted with chlorine gas and coke (C) to provide titanium tetrachloride (TiCl4) which is subsequently purified. The purified titanium tetrachloride is subsequently reduced using magnesium to provide titanium metal. The Kroll method is acomplicated batch process which requires many process steps and extensive amounts of production time. While the Kroll method provides for a titanium product of enhanced quality, the production efficiency does not meet the increasing market demand.

[0006] In recent years, electrochemical and thermochemical processes have been investigated as potential alternatives for titanium metal production. In the Armstrong process, ilmenite ore undergoes carbothermal reduction to Ti-slag and pig Fe, followed by chemical extraction and high temperature chlorination of upgraded synthetic rutile to TiCl4. The TiCl4is subsequently reduced using molten sodium (Na) metal. Although the Armstrong process presents some advantages over the Kroll process, a number of challenges remain. In one aspect, the Armstrong process results in a Ti powder having the consistency of mini sponges, making subsequent processes, such as compacting and sintering, difficult. In another aspect, molten sodium is a costly material, and regenerating Na (from NaCl) is an energy intensive process. Furthermore, the Armstrong process still requires the formation of TiCl4. Therefore, the benefits of the Armstrong process are limited. In the FFC Cambridge process, ilmenite ore undergoes carbothermal reduction to Ti-slag and pig Fe, followed by chemical extraction and electrolysis to electrochemically reduce upgraded synthetic rutile to Ti sponge or powder.

[0007] Ilmenite (FeTiO3) has been found in a great number of countries around the world, some of the more notable ones being Canada, China, South Africa, Norway, and Australia. About 40% of its composition is TiO2, making it a significant source of titanium dioxide. Although both natural rutile and anatase are important titanium sources, they are both scarce and expensive. About 90% of the world's titanium comes from ilmenite. Despite its availability, ilmenite has not been extensively exploited in traditional metallurgical techniques for titanium production because of its high production cost. In Australia and Canada, volcanic ilmenite is the traditional source of titanium ore, while placer ilmenite and rutile constitute the majority of the ilmenite resources.

[0008] A method for producing titanium powder is disclosed in US 10,689,730 B2. The method comprises reacting TiO2with a metallic reducing agent, followed by dehydrogenating and deoxygenating the resulting hydrogenated titanium product.

[0009] A process for producing titanium metal is disclosed in US 8,092,570 B2. A feed material (TiCl4) and magnesium are fed into the center of an RF thermal plasma discharge, followed by collecting and depositing of the titanium metal at a predetermined temperature not lower than the boiling point of magnesium chloride and not higher than the boiling point of the titanium metal.

[0010] A method for producing titanium metal from titanium oxides, using magnesium vapor reduction, is disclosed in US 2018 / 0223393. A feed material is first subjected to an acid leaching step for iron removal, followed by heating the leached product in the presence of a magnesium source in a sealed reaction chamber filled with an inert gas, at temperatures ranging from 850 to 1000°C.

[0011] A process for the production of titanium metal from a titanium metal containing ore is disclosed in US 6,824,585 B2. The ore material is first subjected to a chlorination step to produce TiCl4, followed by reacting the TiCl4with a metallic reductant in a plasma to provide molten titanium metal.

[0012] Aluminum is used in a wide variety of goods because of its low weight, high strength-to-weight ratio, excellent electrical and thermal conductivity, and great resistance to corrosion. As a consequence, aluminum has surpassed steel as the world's most widely used metal, and the aluminum manufacturing industry now dominates the non-ferrous metal sector in terms of output.

[0013] A novel process for the extraction of metal values from a metal containing feed material in high yield and purity, that is of an environmentally cleaner design, and overcoming the technical and economic limitations of the existing commercial processes, is of commercial interest. SUMMARY

[0014] The present disclosure broadly relates to the production of metals. More specially, the present disclosure relates to the plasma reduction of metal oxides. Yet more specifically, the present disclosure relates to a process for the production of one or more metals from a feed material comprising the one or more metals as metal oxides using a DC thermal plasma torch and a plasma gas comprising CO2and a hydrocarbon.

[0015] In an aspect, the present disclosure relates to a process for metal oxide reduction, the process comprising: producing a plasma to bring the metal oxide to a reaction temperature ranging from about 500°C to about 5000°C; and reacting the metal oxide at the reaction temperature ranging from about 500°C to about 5000°C with a reducing gas mixture comprising CO2and a hydrocarbon to produce a reduced metal oxide. In an embodiment of the present disclosure, the process further comprises cooling the reduced metal oxide to a temperature ranging from about 25°C to about 500°C by injecting a quench gas. In an embodiment of the present disclosure, the process further comprises collecting the reduced metal oxide. In an embodiment of the present disclosure,the reducing gas mixture comprises a CO2 / hydrocarbon ratio ranging from about 2:1 to about 1:4. In an embodiment of the present disclosure, the hydrocarbon is at least one of natural gas, CH4, C2H6, and C3H8. In an embodiment of the present disclosure, the hydrocarbon is CH4. In an embodiment of the present disclosure, the metal oxide is comprised in an ore material, a concentrate or a mining residue. In an embodiment of the present disclosure, the metal oxide is at least one of Li2O, MgO, Al2O3, TiO2, V2O5, Cr2O3, MnO2, Fe3O4, CoO, NiO, CuO, ZnO, Ga2O3, Y2O3, ZrO2, Nb2O5, Mo2O3, Tc2O7, RuO2, Rh2O3, PdO, Au2O, CdO, In2O3, SnO, La2O3, HfO2, Ta2O5, WO2, Re2O7, OsO4, IrO2, PtO2, Au2O3, Tl2O3, CeO2, Nd2O3, Pr6O11, Sm2O3, Gd2O3, Dy2O3, Yb2O3, Er2O3and mixtures thereof. In an embodiment of the present disclosure, the ore material comprises ilmenite.

[0016] In an aspect, the present disclosure relates to a process for metal oxide reduction, the process comprising: producing a reducing plasma to bring the metal oxide to a reaction temperature ranging from about 500°C to about 5000°C; and reacting the metal oxide at the reaction temperature ranging from about 500°C to about 5000°C with the reducing plasma to produce a reduced metal oxide. In an embodiment of the present disclosure, the process further comprises cooling the reduced metal oxide to a temperature ranging from about 25°C to about 500°C by injecting a quench gas. In an embodiment of the present disclosure, the process further comprises collecting the reduced metal oxide. In an embodiment of the present disclosure, the reducing plasma is produced using a gas mixture comprising CO2and a hydrocarbon. In an embodiment of the present disclosure, the reducing gas mixture comprises a CO2 / hydrocarbon ratio ranging from about 2:1 to about 1:4. In an embodiment of the present disclosure, the hydrocarbon is at least one of natural gas, CH4, C2H6, and C3H8. In an embodiment of the present disclosure, the hydrocarbon is CH4. In an embodiment of the present disclosure, the metal oxide is comprised in an ore material, a concentrate or a mining residue. In an embodiment of the present disclosure, the metal oxide is at least one of Li2O, MgO, Al2O3, TiO2, V2O5, Cr2O3, MnO2, Fe3O4, CoO, NiO, CuO, ZnO, Ga2O3, Y2O3, ZrO2, Nb2O5, Mo2O3, Tc2O7, RuO2, Rh2O3, PdO, Au2O, CdO, In2O3, SnO, La2O3, HfO2, Ta2O5, WO2, Re2O7, OsO4, IrO2, PtO2, Au2O3, Tl2O3, CeO2, Nd2O3, Pr6O11, Sm2O3, Gd2O3, Dy2O3, Yb2O3, Er2O3and mixtures thereof. In an embodiment of the present disclosure, the ore material comprises ilmenite.

[0017] In an aspect, the present disclosure relates to a process for the production of a metal from its oxide ore, the process comprising: producing a plasma to bring the oxide ore to a reaction temperature ranging from about 500°C to about 5000°C; and reacting the oxide ore at the reaction temperature ranging from about 500°C to about 5000°C with a reducing gas mixture comprising CO2and a hydrocarbon to produce a reduced oxide ore.In an embodiment of the present disclosure, the process further comprises cooling the reduced oxide ore to a temperature ranging from about 25°C to about 500°C by injecting a quench gas. In an embodiment of the present disclosure, the process further comprises collecting the reduced oxide ore. In an embodiment of the present disclosure, the reducing gas mixture comprises a CO2 / hydrocarbon ratio ranging from about 2:1 to about 1:4. In an embodiment of the present disclosure, the hydrocarbon is at least one of natural gas, CH4, C2H6, and C3H8. In an embodiment of the present disclosure, the hydrocarbon is CH4. In an embodiment of the present disclosure, the oxide ore comprises at least one metal oxide including Li2O, MgO, Al2O3, TiO2, V2O5, Cr2O3, MnO2, Fe3O4, CoO, NiO, CuO, ZnO, Ga2O3, Y2O3, ZrO2, Nb2O5, Mo2O3, Tc2O7, RuO2, Rh2O3, PdO, Au2O, CdO, In2O3, SnO, La2O3, HfO2, Ta2O5, WO2, Re2O7, OsO4, IrO2, PtO2, Au2O3, Tl2O3, CeO2, Nd2O3, Pr6O11, Sm2O3, Gd2O3, Dy2O3, Yb2O3, Er2O3and mixtures thereof. In an embodiment of the present disclosure, the oxide ore comprises ilmenite.

[0018] In an aspect, the present disclosure relates to a process for metal oxide reduction, the process comprising: determining the constituents of a feed material from which one or more metals are to be extracted; using process simulation and / or modeling software to model a plasma arc reaction for the feed material comprising the one or more metals as metal oxides and a reducing agent comprising CO2and a hydrocarbon; feeding the feed material into a thermal plasma torch producing a material comprising reduced metal oxides. In an embodiment of the present disclosure, the process further comprises producing a plasma to bring the feed material to a reaction temperature ranging from about 500°C to about 5000°C; reacting the feed material at the reaction temperature ranging from about 500°C to about 5000°C with the reducing agent producing the reduced metal oxides; and cooling the reduced metal oxides to a temperature ranging from about 25°C to about 500°C by injecting a quench gas. In an embodiment of the present disclosure, the process further comprises collecting the reduced metal oxides.. In an embodiment of the present disclosure, the reducing agent comprises a CO2 / hydrocarbon ratio ranging from about 2:1 to about 1:4. In an embodiment of the present disclosure, the hydrocarbon is at least one of natural gas, CH4, C2H6, and C3H8. In an embodiment of the present disclosure, the hydrocarbon is CH4. In an embodiment of the present disclosure, the feed material is an ore material, a concentrate or a mining residue. In an embodiment of the present disclosure, the metal oxide is at least one of Li2O, MgO, Al2O3, TiO2, V2O5, Cr2O3, MnO2, Fe3O4, CoO, NiO, CuO, ZnO, Ga2O3, Y2O3, ZrO2, Nb2O5, Mo2O3, Tc2O7, RuO2, Rh2O3, PdO, Au2O, CdO, In2O3, SnO, La2O3, HfO2, Ta2O5, WO2, Re2O7, OsO4, IrO2, PtO2, Au2O3, Tl2O3, CeO2, Nd2O3, Pr6O11, Sm2O3, Gd2O3, Dy2O3, Yb2O3, Er2O3and mixtures thereof. In an embodiment of the present disclosure, the ore material comprises ilmenite.

[0019] In an aspect of the present disclosure, the feed material is an ilmenite concentrate. In a further aspect of the present disclosure, the feed material is alumina (Al2O3). In a further aspect of the present disclosure, the feed material is magnetite. In a further aspect of the present disclosure, the feed material is rutile.

[0020] Also disclosed in the context of the present disclosure are embodiments 1 to 114. Embodiment 1 is a process for metal oxide reduction, the process comprising: producing a plasma to bring the metal oxide to a reaction temperature ranging from about 500°C to about 5000°C; and reacting the metal oxide at the reaction temperature ranging from about 500°C to about 5000°C with a reducing gas mixture comprising CO2and a hydrocarbon to produce a reduced metal oxide. Embodiment 2 is the process of embodiment 1, further comprising cooling the reduced metal oxide to a temperature ranging from about 25°C to about 500°C by injecting a quench gas. Embodiment 3 is the process of embodiment 1 or 2, further comprising collecting the reduced metal oxide. Embodiment 4 is the process of any one of embodiments 1 to 3, wherein reacting the metal oxide with the reducing gas mixture comprises injecting the reducing gas mixture into the plasma. Embodiment 5 is the process of any one of embodiments 1 to 4, wherein the reducing gas mixture comprises a CO2 / hydrocarbon ratio ranging from about 2:1 to about 1:4. Embodiment 6 is the process of any one of embodiments 1 to 5, wherein the hydrocarbon is at least one of natural gas, CH4, C2H6, and C3H8. Embodiment 7 is the process of embodiment 6, wherein the hydrocarbon is CH4. Embodiment 8 is the process of any one of embodiments 1 to 7, wherein the metal oxide is comprised in an ore material, a concentrate or a mining residue. Embodiment 9 is the process of embodiment 8, wherein the metal oxide is at least one of Li2O, MgO, Al2O3, TiO2, V2O5, Cr2O3, MnO2, Fe3O4, CoO, NiO, CuO, ZnO, Ga2O3, Y2O3, ZrO2, Nb2O5, Mo2O3, Tc2O7, RuO2, Rh2O3, PdO, Au2O, CdO, In2O3, SnO, La2O3, HfO2, Ta2O5, WO2, Re2O7, OsO4, IrO2, PtO2, Au2O3, Tl2O3, CeO2, Nd2O3, Pr6O11, Sm2O3, Gd2O3, Dy2O3, Yb2O3, Er2O3and mixtures thereof. Embodiment 10 is the process of embodiment 8, wherein the ore material comprises ilmenite. Embodiment 11 is the process of any one of embodiments 1 to 10, wherein the plasma is produced using a readily ionizable working gas. Embodiment 12 is the process of embodiment 11, wherein the working gas comprises at least one of He, Ar and N2. Embodiment 13 is the process of any one of embodiments 1 to 12, wherein the plasma is produced using a DC thermal plasma torch, an alternating current (AC) thermal plasma torch, a radio-frequency (RF) thermal plasma torch, an induction thermal plasma torch, or a microwave plasma. Embodiment 14 is the process of embodiment 13, wherein the DC thermal plasma torch is a transferred arc plasma torch or a non-transferred arc plasma torch. Embodiment 15 is the process of embodiment 13 or 14, wherein the DC thermalplasma torch comprises an anode and a cathode, and wherein a carbon layer is deposited on the cathode surface during operation. Embodiment 16 is the process of embodiment 15, further comprising adjusting the electric current through the cathode and anode based on post-plasma mixture composition analysis. Embodiment 17 is the process of any one of embodiments 1 to 16, further comprising adjusting a composition of the reducing gas mixture based on post-plasma mixture composition analysis. Embodiment 18 is the process of any one of embodiments 1 to 17, further comprising adjusting a rate of injection of the reducing gas mixture based on post-plasma mixture composition analysis. Embodiment 19 is the process of any one of embodiments 1 to 18, wherein the reduced metal oxide is at least one of Li, Mg, Al, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, In, Sn, La, Hf, Ta, W, Re, Os, Ir, Pt, Au, Ce, Nd, Pr, Sm, Gd, Dy, Yb, Er and Tl. Embodiment 20 is the process of any one of embodiments 1 to 19, further comprising leaching the reduced metal oxide in an acidic solution thereby producing a pregnant solution. Embodiment 21 is the process of embodiment 20, wherein the leaching is performed at a temperature ranging between 20˚C and 300˚C. Embodiment 22 is the process of embodiment 20 or 21, wherein the acidic solution is at least one of a sulfuric acid solution, a hydrochloric acid solution, a nitric acid solution, a carbonic acid solution, an oxalic acid solution, or a combination of any thereof. Embodiment 23 is the process of embodiment 22, wherein the acidic solution is a sulfuric acid solution. Embodiment 24 is the process of embodiment 23, wherein the sulfuric acid solution comprises a mass percentage from about 5 wt.% H2SO4to about 100 wt.% H2SO4. Embodiment 25 is the process of embodiment 24, wherein the sulfuric acid solution comprises a mass percentage from about 15 wt.% H2SO4to about 80 wt.% H2SO4. Embodiment 26 is the process of embodiment 24 or 25, wherein the sulfuric acid solution has a mass percentage of about 30 wt.% H2SO4. Embodiment 27 is the process of any one of embodiments 23 to 26, wherein the sulfuric acid leaching is performed over a period ranging from about 30 minutes to about 3 hours. Embodiment 28 is the process of embodiment 27, wherein the sulfuric acid leaching is performed over a period ranging from about 1 hour to about 2.5 hours. Embodiment 29 is the process of embodiment 27 or 28, wherein the sulfuric acid leaching is performed over a period of about 1.5 hours.

[0021] Embodiment 30 is a process for metal oxide reduction, the process comprising: producing a reducing plasma to bring the metal oxide to a reaction temperature ranging from about 500°C to about 5000°C; and reacting the metal oxide at the reaction temperature ranging from about 500°C to about 5000°C with the reducing plasma to produce a reduced metal oxide. Embodiment 31 is the process of embodiment 30, further comprising cooling the reduced metal oxide to a temperature ranging from about 25°C toabout 500°C by injecting a quench gas. Embodiment 32 is the process of embodiment 30 or 31, further comprising collecting the reduced metal oxide. Embodiment 33 is the process of any one of embodiments 30 to 32, wherein the reducing plasma is produced using a reducing gas mixture comprising CO2and a hydrocarbon. Embodiment 34 is the process of any one of embodiments 30 to 33, wherein the reducing gas mixture comprises a CO2 / hydrocarbon ratio ranging from about 2:1 to about 1:4. Embodiment 35 is the process of any one of embodiments 30 to 34, wherein the hydrocarbon is at least one of natural gas, CH4, C2H6, and C3H8. Embodiment 36 is the process of embodiment 35, wherein the hydrocarbon is CH4. Embodiment 37 is the process of any one of embodiments 30 to 36, wherein the metal oxide is comprised in an ore material, a concentrate or a mining residue. Embodiment 38 is the process of embodiment 37, wherein the metal oxide is at least one of Li2O, MgO, Al2O3, TiO2, V2O5, Cr2O3, MnO2, Fe3O4, CoO, NiO, CuO, ZnO, Ga2O3, Y2O3, ZrO2, Nb2O5, Mo2O3, Tc2O7, RuO2, Rh2O3, PdO, Au2O, CdO, In2O3, SnO, La2O3, HfO2, Ta2O5, WO2, Re2O7, OsO4, IrO2, PtO2, Au2O3, Tl2O3, CeO2, Nd2O3, Pr6O11, Sm2O3, Gd2O3, Dy2O3, Yb2O3, Er2O3 and mixtures thereof. Embodiment 39 is the process of embodiment 37, wherein the ore material comprises ilmenite. Embodiment 40 is the process of any one of embodiments 30 to 39, wherein the plasma is produced using a DC thermal plasma torch, an alternating current (AC) thermal plasma torch, a radio-frequency (RF) thermal plasma torch, an induction thermal plasma torch, or a microwave plasma. Embodiment 41 is the process of embodiment 40, wherein the DC thermal plasma torch is a transferred arc plasma torch or a non-transferred arc plasma torch. Embodiment 42 is the process of embodiment 40 or 41, wherein the DC thermal plasma torch comprises an anode and a cathode, and wherein a carbon layer is deposited on the cathode surface during operation. Embodiment 43 is the process of embodiment 42, further comprising adjusting the electric current through the cathode and anode based on post-plasma mixture composition analysis. Embodiment 44 is the process of any one of embodiments 30 to 43, further comprising adjusting a composition of the reducing gas mixture based on post-plasma mixture composition analysis. Embodiment 45 is the process of any one of embodiments 30 to 44, further comprising adjusting a rate of injection of the reducing gas mixture based on post-plasma mixture composition analysis. Embodiment 46 is the process of any one of embodiments 30 to 45, wherein the reduced metal oxide is at least one of Li, Mg, Al, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, In, Sn, La, Hf, Ta, W, Re, Os, Ir, Pt, Au, Ce, Nd, Pr, Sm, Gd, Dy, Yb, Er and Tl. Embodiment 47 is the process of any one of embodiments 30 to 46, further comprising leaching the reduced metal oxide in an acidic solution thereby producing a pregnant solution. Embodiment 48 is the process of embodiment 47, whereinthe leaching is performed at a temperature ranging between 20˚C and 300˚C. Embodiment 49 is the process of embodiment 47 or 48, wherein the acidic solution is at least one of a sulfuric acid solution, a hydrochloric acid solution, a nitric acid solution, a carbonic acid solution, an oxalic acid solution, or a combination of any thereof. Embodiment 50 is the process of embodiment 49, wherein the acidic solution is a sulfuric acid solution. Embodiment 51 is the process of embodiment 50, wherein the sulfuric acid solution comprises a mass percentage from about 5 wt.% H2SO4to about 100 wt.% H2SO4. Embodiment 52 is the process of embodiment 51, wherein the sulfuric acid solution comprises a mass percentage from about 15 wt.% H2SO4to about 80 wt.% H2SO4. Embodiment 53 is the process of embodiment 51 or 52, wherein the sulfuric acid solution has a mass percentage of about 30 wt.% H2SO4. Embodiment 54 is the process of any one of embodiments 50 to 53, wherein the sulfuric acid leaching is performed over a period ranging from about 30 minutes to about 3 hours. Embodiment 55 is the process of embodiment 54, wherein the sulfuric acid leaching is performed over a period ranging from about 1 hour to about 2.5 hours. Embodiment 56 is the process of embodiment 54 or 55, wherein the sulfuric acid leaching is performed over a period of about 1.5 hours. Embodiment 57 is the process of embodiment 2 or 31, wherein the quench gas comprises Ar.

[0022] Embodiment 58 is a process for the production of a metal from its oxide ore, the process comprising: producing a plasma to bring the oxide ore to a reaction temperature ranging from about 500°C to about 5000°C; and reacting the oxide ore at the reaction temperature ranging from about 500°C to about 5000°C with a reducing gas mixture comprising CO2and a hydrocarbon to produce a reduced oxide ore. Embodiment 59 is the process of embodiment 58, further comprising cooling the reduced oxide or to a temperature ranging from about 25°C to about 500°C by injecting a quench gas. Embodiment 60 is the process of embodiment 58 or 59, further comprising collecting the reduced oxide ore. Embodiment 61 is the process of any one of embodiments 58 to 60, wherein reacting the oxide ore with the reducing gas mixture comprises injecting the reducing gas mixture into the plasma. Embodiment 62 is the process of any one of embodiments 58 to 61, wherein the reducing gas mixture comprises a CO2 / hydrocarbon ratio ranging from about 2:1 to about 1:4. Embodiment 63 is the process of any one of embodiments 58 to 62, wherein the hydrocarbon is at least one of natural gas, CH4, C2H6, and C3H8. Embodiment 64 is the process of embodiment 63, wherein the hydrocarbon is CH4. Embodiment 65 is the process of any one of embodiments 58 to 64, wherein the oxide ore comprises at least one metal oxide including Li2O, MgO, Al2O3, TiO2, V2O5, Cr2O3, MnO2, Fe3O4, CoO, NiO, CuO, ZnO, Ga2O3, Y2O3, ZrO2, Nb2O5, Mo2O3, Tc2O7,RuO2, Rh2O3, PdO, Au2O, CdO, In2O3, SnO, La2O3, HfO2, Ta2O5, WO2, Re2O7, OsO4, IrO2, PtO2, Au2O3, Tl2O3, CeO2, Nd2O3, Pr6O11, Sm2O3, Gd2O3, Dy2O3, Yb2O3, Er2O3and mixtures thereof. Embodiment 66 is the process of embodiment 65, wherein the oxide ore comprises ilmenite. Embodiment 67 is the process of any one of embodiments 58 to 66, wherein the plasma is produced using a readily ionizable working gas. Embodiment 68 is the process of embodiment 67, wherein the working gas comprises at least one of He, Ar and N2. Embodiment 69 is the process of any one of embodiments 58 to 68, wherein the plasma is produced using a DC thermal plasma torch, an alternating current (AC) thermal plasma torch, a radio-frequency (RF) thermal plasma torch, an induction thermal plasma torch, or a microwave plasma. Embodiment 70 is the process of embodiment 69, wherein the DC thermal plasma torch is a transferred arc plasma torch or a non-transferred arc plasma torch. Embodiment 71 is the process of embodiment 69 or 70, wherein the DC thermal plasma torch comprises an anode and a cathode, and wherein a carbon layer is deposited on the cathode surface during operation. Embodiment 72 is the process of embodiment 71, further comprising adjusting the electric current through the cathode and anode based on post-plasma mixture composition analysis. Embodiment 73 is the process of any one of embodiments 58 to 72, further comprising adjusting a composition of the reducing gas mixture based on post-plasma mixture composition analysis. Embodiment 74 is the process of any one of embodiments 58 to 73, further comprising adjusting a rate of injection of the reducing gas mixture based on post-plasma mixture composition analysis. Embodiment 75 is the process of any one of embodiments 58 to 74, wherein the metal is at least one of Li, Mg, Al, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, In, Sn, La, Hf, Ta, W, Re, Os, Ir, Pt, Au, Ce, Nd, Pr, Sm, Gd, Dy, Yb, Er and Tl. Embodiment 76 is the process of any one of embodiments 58 to 75, further comprising leaching the reduced oxide ore in an acidic solution thereby producing a pregnant solution. Embodiment 77 is the process of embodiment 76, wherein the leaching is performed at a temperature ranging between 20˚C and 300˚C. Embodiment 78 is the process of embodiment 76 or 77, wherein the acidic solution is at least one of a sulfuric acid solution, a hydrochloric acid solution, a nitric acid solution, a carbonic acid solution, an oxalic acid solution, or a combination of any thereof. Embodiment 79 is the process of embodiment 78, wherein the acidic solution is a sulfuric acid solution. Embodiment 80 is the process of embodiment 79, wherein the sulfuric acid solution comprises a mass percentage from about 5 wt.% H2SO4 to about 100 wt.% H2SO4. Embodiment 81 is the process of embodiment 80, wherein the sulfuric acid solution comprises a mass percentage from about 15 wt.% H2SO4to about 80 wt.% H2SO4. Embodiment 82 is the process of embodiment 80 or 81, wherein the sulfuric acid solution has a mass percentageof about 30 wt.% H2SO4. Embodiment 83 is the process of any one of embodiments 79 to 82, wherein the sulfuric acid leaching is performed over a period ranging from about 30 minutes to about 3 hours. Embodiment 84 is the process of embodiment 83, wherein the sulfuric acid leaching is performed over a period ranging from about 1 hour to about 2.5 hours. Embodiment 85 is the process of embodiment 83 or 84, wherein the sulfuric acid leaching is performed over a period of about 1.5 hours.

[0023] Embodiment 86 is a process for metal oxide reduction, the process comprising: determining the constituents of a feed material from which one or more metals are to be extracted; using process simulation and / or modeling software to model a plasma arc reaction for the feed material comprising the one or more metals as metal oxides and a reducing agent comprising CO2and a hydrocarbon; feeding the feed material into a thermal plasma torch producing a material comprising reduced metal oxides. Embodiment 87 is the process of embodiment 86, further comprising: producing a plasma to bring the feed material to a reaction temperature ranging from about 500°C to about 5000°C; reacting the feed material at the reaction temperature ranging from about 500°C to about 5000°C with the reducing agent producing a reduced metal oxide; and cooling the reduced metal oxides to a temperature ranging from about 25°C to about 500°C by injecting a quench gas. Embodiment 88 is the process of embodiment 86 or 87, further comprising collecting the reduced metal oxides. Embodiment 89 is the process of any one of embodiments 86 to 88, wherein reacting the feed material with the reducing agent comprises injecting the reducing agent into the plasma. Embodiment 90 is the process of any one of embodiments 86 to 89, wherein the reducing agent comprises a CO2 / hydrocarbon ratio ranging from about 2:1 to about 1:4. Embodiment 91 is the process of any one of embodiments 86 to 90, wherein the hydrocarbon is at least one of natural gas, CH4, C2H6, and C3H8. Embodiment 92 is the process of embodiment 91, wherein the hydrocarbon is CH4. Embodiment 93 is the process of any one of embodiments 86 to 90, wherein the feed material is an ore material, a concentrate or a mining residue. Embodiment 94 is the process of any one of embodiments 86 to 93, wherein the metal oxide is at least one of Li2O, MgO, Al2O3, TiO2, V2O5, Cr2O3, MnO2, Fe3O4, CoO, NiO, CuO, ZnO, Ga2O3, Y2O3, ZrO2, Nb2O5, Mo2O3, Tc2O7, RuO2, Rh2O3, PdO, Au2O, CdO, In2O3, SnO, La2O3, HfO2, Ta2O5, WO2, Re2O7, OsO4, IrO2, PtO2, Au2O3, Tl2O3, CeO2, Nd2O3, Pr6O11, Sm2O3, Gd2O3, Dy2O3, Yb2O3, Er2O3and mixtures thereof. Embodiment 95 is the process of embodiment 86, wherein the feed material comprises ilmenite. Embodiment 96 is the process of embodiment 87, wherein the plasma is produced using a readily ionizable working gas. Embodiment 97 is the process of embodiment 96, wherein the working gas comprises at least one of He, Ar and N2. Embodiment 98 is the process ofany one of embodiments 86 to 98, wherein the thermal plasma torch comprises a DC thermal plasma torch, an alternating current (AC) thermal plasma torch, a radio-frequency (RF) thermal plasma torch, an induction thermal plasma torch, or a microwave plasma. Embodiment 99 is the process of embodiment 98, wherein the DC thermal plasma torch is a transferred arc plasma torch or a non-transferred arc plasma torch. Embodiment 100 is the process of embodiment 98 or 99, wherein the DC thermal plasma torch comprises an anode and a cathode, and wherein a carbon layer is deposited on the cathode surface during operation. Embodiment 101 is the process of embodiment 100, further comprising adjusting the electric current through the cathode and anode based on post-plasma mixture composition analysis. Embodiment 102 is the process of any one of embodiments 86 to 101, further comprising adjusting a composition of the reducing agent based on post- plasma mixture composition analysis. Embodiment 103 is the process of any one of embodiments 86 to 102, further comprising adjusting a rate of injection of the reducing agent based on post-plasma mixture composition analysis. Embodiment 104 is the process of any one of embodiments 86 to 103, wherein the reduced metal oxide is at least one of Li, Mg, Al, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, In, Sn, La, Hf, Ta, W, Re, Os, Ir, Pt, Au, Ce, Nd, Pr, Sm, Gd, Dy, Yb, Er and Tl. Embodiment 105 is the process of any one of embodiments 86 to 104, further comprising leaching the reduced metal oxides in an acidic solution thereby producing a pregnant solution. Embodiment 106 is the process of embodiment 105, wherein the leaching is performed at a temperature ranging between 20˚C and 300˚C. Embodiment 107 is the process of embodiment 105 or 106, wherein the acidic solution is at least one of a sulfuric acid solution, a hydrochloric acid solution, a nitric acid solution, a carbonic acid solution, an oxalic acid solution, or a combination of any thereof. Embodiment 108 is the process of embodiment 107, wherein the acidic solution is a sulfuric acid solution. Embodiment 109 is the process of embodiment 108, wherein the sulfuric acid solution comprises a masspercentage from about 5 wt.% H2SO4to about 100 wt.% H2SO4. Embodiment 110 is theprocess of embodiment 109, wherein the sulfuric acid solution comprises a mass percentage from about 15 wt.% H2SO4to about 80 wt.% H2SO4. Embodiment 111 is the process of embodiment 109 or 110, wherein the sulfuric acid solution has a mass percentage of about 30 wt.% H2SO4. Embodiment 112 is the process of any one of embodiments 108 to 111, wherein the sulfuric acid leaching is performed over a period ranging from about 30 minutes to about 3 hours. Embodiment 113 is the process of embodiment 112, wherein the sulfuric acid leaching is performed over a period ranging from about 1 hour to about 2.5 hours. Embodiment 114 is the process of embodiment 112 or 113, wherein the sulfuric acid leaching is performed over a period of about 1.5 hours.

[0024] The word “a” or “an” when used in conjunction with the term “comprising” in the claims and / or the specification may mean “one”, but it is also consistent with the meaning of “one or more”, “at least one”, and “one or more than one” unless the content clearly dictates otherwise. Similarly, the word “another” may mean at least a second or more unless the content clearly dictates otherwise.

[0025] As used in this specification and claim(s), the words “comprising” (and any form of comprising, such as “comprise” and “comprises”), “having” (and any form of having, such as “have” and “has”), “including” (and any form of including, such as “include” and “includes”) or “containing” (and any form of containing, such as “contain” and “contains”), are inclusive or open-ended and do not exclude additional, unrecited elements or process steps.

[0026] As used in this specification and claim(s), the word “consisting” and its derivatives, are intended to be close ended terms that specify the presence of stated features, elements, components, groups, integers, and / or steps, and also exclude the presence of other unstated features, elements, components, groups, integers and / or steps.

[0027] The term “consisting essentially of”, as used herein, is intended to specify the presence of the stated features, elements, components, groups, integers, and / or steps as well as those that do not materially affect the basic and novel characteristic(s) of these features, elements, components, groups, integers, and / or steps.

[0028] The terms “about”, “substantially” and “approximately” as used herein mean a reasonable amount of deviation of the modified term such that the end result is not significantly changed. These terms of degree should be construed as including a deviation of at least ±5% of the modified term if this deviation would not negate the meaning of the word it modifies.

[0029] The foregoing and other advantages and features of the present disclosure will become more apparent upon reading of the following non-restrictive detailed description of illustrative embodiments thereof, with reference to the accompanying drawings / figures. It should be understood, however, that the detailed description and the illustrative embodiments, while indicating specific embodiments of the disclosure, are given by way of illustration only, since various changes and modifications within the spirit and scope of the disclosure will become apparent to those skilled in the art from this description.BRIEF DESCRIPTION OF THE DRAWINGS / FIGURES

[0030] The following figures / drawings form part of the present specification and are included to further demonstrate certain aspects of the present specification. The present specification may be better understood by reference to one or more of these figures / drawings in combination with the detailed description. In the appended drawings / figures:

[0031] FIG. 1 - Illustration of a SEM image of ilmenite reduced using a DC thermal plasma torch and a plasma gas comprising CO2and a hydrocarbon, in accordance with an embodiment of the present disclosure.

[0032] FIG.2 - Illustration of a DC thermal plasma torch and an apparatus including the DC thermal plasma torch, in accordance with an embodiment of the present disclosure

[0033] FIG. 3 - Illustration of an apparatus including a DC thermal plasma torch, in accordance with an embodiment of the present disclosure.

[0034] FIG. 4 - Illustration of a DC thermal plasma torch, in accordance with an embodiment of the present disclosure.

[0035] FIG.5 - Illustration of the equilibrium log (mole) of a CO2 / CH4plasma mixture as a function of temperature in accordance with an embodiment of the present disclosure.

[0036] FIG.6 - Illustration of the equilibrium log (mole) of a CO2 / CH4plasma mixture and ilmenite (FeTiO3) as a function of temperature in accordance with an embodiment of the present disclosure.

[0037] FIG. 7 - Illustration of the Gibbs free energy for ilmenite reduction using a CO2 / CH4plasma mixture (Reaction 1: CO2+ CH4→ 2 CO + 2 H2; Reaction 2: FeTiO3+ 2 CO + 2 H2→ Ti + Fe + CO + H2O), in accordance with an embodiment of the present disclosure.

[0038] FIG.8 - Illustration of the temperature variation inside the reactor for heating and cooling phases of the reductive thermal plasma process using a CO2 / CH4plasma mixture of 1:1, in accordance with an embodiment of the present disclosure.

[0039] FIG.9 - Illustration of an X-ray diffractogram of an ilmenite concentrate before and after reductive thermal plasma treatment, in accordance with an embodiment of the present disclosure.

[0040] FIG.10 - Illustration of an SEM image of an ilmenite feed material (a) before and (b) after reductive thermal plasma treatment, in accordance with an embodiment of the present disclosure.

[0041] FIG.11 - Illustration of an EDS image of an ilmenite feed material (a) before and (b) after reductive thermal plasma treatment (CO2 / CH41:1), in accordance with an embodiment of the present disclosure.

[0042] FIG.12 - Illustration of a mapping distribution of the main elements (Ti, Fe, and O) of an ilmenite concentrate feed before reductive thermal plasma treatment, in accordance with an embodiment of the present disclosure.

[0043] FIG.13 - Illustration of a mapping distribution of the main elements (Ti, Fe, and O) of an ilmenite concentrate feed after reductive thermal plasma treatment, in accordance with an embodiment of the present disclosure.

[0044] FIG. 14 - Illustration of the enthalpies of a CO2 / CH4plasma torch, an argon plasma torch, and a nitrogen plasma torch.

[0045] FIG.15 - Illustration of an X-ray diffractogram of an ilmenite concentrate before and after reductive thermal plasma treatment (CO2 / CH41:1), in accordance with an embodiment of the present disclosure.

[0046] FIG.16 - Illustration of an FTIR spectrum of an ilmenite concentrate before and after reductive thermal plasma treatment, in accordance with an embodiment of the present disclosure.

[0047] FIG. 17 - Illustration of the Gibbs free energy for ilmenite reduction using a CO2 / CH4plasma mixture (Reaction 1: 2 CO2+ CH4; Reaction 2: FeO + 2 CO2+ CH4; Reaction 3: TiO2+ 2 CO2+ CH4; Reaction 4: FeTiO3+ 2 CO2+ CH4), in accordance with an embodiment of the present disclosure.

[0048] FIG.18 - Illustration of an X-ray diffractogram of an ilmenite concentrate before and after reductive thermal plasma treatment (CO2 / CH42:1), in accordance with an embodiment of the present disclosure.

[0049] FIG.19 - Illustration of an EDS image of an ilmenite feed material (a) before and (b) after reductive thermal plasma treatment (CO2 / CH42:1), in accordance with an embodiment of the present disclosure.

[0050] FIG.20 - Illustration of the power variation over time of a plasma torch operating using a plasma gas having CO2 / CH4ratio of 1:1 and 2:1 respectively, in accordance with an embodiment of the present disclosure.

[0051] FIG.21 - Illustration of the temperature variation inside the reactor of heating and cooling phases of the thermal plasma reduction process using a CO2 / CH4plasma mixture of 1:1 and 2:1 respectively, in accordance with an embodiment of the present disclosure.

[0052] FIG.22 - Illustration of the equilibrium log (mole) of a CO2 / CH4plasma mixture (1:1) and ilmenite Al2O3as a function of temperature, in accordance with an embodiment of the present disclosure.

[0053] FIG.23 - Illustration of the equilibrium log (mole) of a CO2 / CH4plasma mixture (1:1) and ilmenite TiO2as a function of temperature, in accordance with an embodiment of the present disclosure.

[0054] FIG.24 - Illustration of the equilibrium log (mole) of a CO2 / CH4plasma mixture (1:1) and ilmenite Fe3O4 as a function of temperature, in accordance with an embodiment of the present disclosure.

[0055] FIG.25 - Illustration of an X-ray diffractogram of an Al2O3sample before and after reductive thermal plasma treatment (CO2 / CH41:1), in accordance with an embodiment of the present disclosure.

[0056] FIG.26 - Illustration of an X-ray diffractogram of a TiO2sample before and after reductive thermal plasma treatment (CO2 / CH41:1), in accordance with an embodiment of the present disclosure.

[0057] FIG.27 - Illustration of an X-ray diffractogram of a Fe3O4sample (magnetite) before and after reductive thermal plasma treatment (CO2 / CH41:1), in accordance with an embodiment of the present disclosure.

[0058] FIG. 28 - Illustration of an X-ray diffractogram of a sample consisting of a mixture of TiO2and Fe3O4after reductive thermal plasma treatment (CO2 / CH41:1), in accordance with an embodiment of the present disclosure.

[0059] FIG.29 - Illustration of a plasma reactor comprising an inlet (16), exhaust (17), thermocouple (18), view port (19), conical bed (20), air manifold (21), cooling water outlets (22, 23), cooling water inlets (24, 25), plasma gas inlet (26), and plasma torch (27), in accordance with an embodiment of the present disclosure.

[0060] FIG. 30 - Illustration of the cone section of the plasma reactor comprising volatile particles (28), plasma jet (29), trapped particles (30) and solidified phase (31), in accordance with an embodiment of the present disclosure. DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

[0061] The present disclosure broadly relates to the production of metals. More specially, the present disclosure relates to the plasma reduction of metal oxides. Yet more specifically, the present disclosure relates to a process for the production of one or more metals from a feed material comprising the one or more metals as metal oxides using a DC thermal plasma torch and a plasma gas comprising CO2and a hydrocarbon.

[0062] With reference to FIGs.2 and 3, illustrated therein is a DC thermal plasma torch and an apparatus including the DC thermal plasma torch, in accordance with an embodiment of the present disclosure. The apparatus was equipped with a spouted bed reactor comprising a bottom cone in direct contact with the plasma where temperatures can exceed 2000°C. The walls of the reactor are cooled using cold water to avoid overheating and deformation of reactor walls. The apparatus was further equipped with one or more filters to remove fine particulate material from the exit gasses. The reducing plasma gas mixture was comprised of CO2and a hydrocarbon. In an embodiment of the present disclosure, the reducing plasma gas mixture comprises a CO2 / hydrocarbon ratio ranging from about 1:1 to about 2:1. In an embodiment of the present disclosure, the hydrocarbon is at least one of CH4, C2H6, and C3H8. In an embodiment of the present disclosure, the hydrocarbon is CH4. Reducing the CO2 / CH4ratio from 2:1 to 1:1 (i.e. increasing the amount of CH4relative to CO2) increases the reducing power of the plasma gas. In further embodiments of the present disclosure, the current and voltage of the plasma torch were kept constant at 252 amps and 150 V respectively. The pressure within the torch was maintained close to atmospheric pressure or near 760 torr. The reducing plasma gas mixture comprising CO2and a hydrocarbon such as CH4advantageously provides for the deposition of a carbon layer on the cathode surface during operation. The reduced ilmenite product was cooled using a flow of argon. In further embodiments of the present disclosure, the metal oxide containing feed material was subjected to plasma treatment for periods ranging from 1 to 5 minutes.

[0063] In an aspect, the present disclosure relates to a process for the production of high grade metals using a DC thermal plasma torch and a reducing plasma gas mixture comprising CO2 and a hydrocarbon. In embodiments of the present disclosure, the high grade metals comprise titanium and iron.

[0064] In an aspect, the present disclosure relates to a process for metal oxide reduction using a DC thermal plasma torch and a reducing plasma gas mixture comprising CO2and a hydrocarbon. The use of a gas mixture comprising CO2and a hydrocarbon such as CH4advantageously provides for generating a plasma exhibiting high enthalpy and high thermal conductivity. A plasma gas mixture comprising CO2advantageously provides for higher plasma power at lower gas flow rates relative to plasma gasses such as Ar or mixtures such as Ar / CH4. Furthermore, the use of a gas mixture comprising CO2and a hydrocarbon such as CH4advantageously provides for extending the life of the cathode by deposition of a carbon layer on the cathode surface during operation. The carbon layer protects the cathode from erosion. In an embodiment of the present disclosure, the source of the metal oxide comprises ilmenite.

[0065] In an aspect, the present disclosure relates to a process for the production of a metal from its oxide ore using a DC thermal plasma torch and a reducing plasma gas mixture comprising CO2and a hydrocarbon. In an embodiment of the present disclosure, the process provides for the production of titanium metal. In an embodiment of the present disclosure, the process provides for the production of iron metal. In an embodiment of the present disclosure, the process provides for the production of aluminum metal.

[0066] In an aspect, the present disclosure relates to a process for the production of titanium and / or iron metal from its oxide ore using a DC thermal plasma torch and a reducing plasma gas mixture comprising CO2and a hydrocarbon. In an embodiment of the present disclosure, the source of the metal oxide comprises ilmenite. XRD and SEM were used to examine the ilmenite concentrate before and after it was subjected to reductive thermal treatment using the DC thermal plasma torch. The results show that titanium and / or iron metal can be advantageously produced using the DC thermal plasma torch and a reducing plasma gas mixture comprising CO2and a hydrocarbon. Moreover, XRD and SEM analysis of the ilmenite concentrate after reductive thermal treatment illustrated that the reductive thermal plasma treatment not only provides for the substantially quantitative conversion of the metal oxides into their corresponding metal values but also advantageously provides for the separation of the metal values. It is surmised that this separation is at least in part due to the differences in the physical properties of the respective metal values (e.g. melting points etc.).

[0067] In an embodiment of the present disclosure, the process for metal oxide reduction is performed using a DC thermal plasma torch and a reducing gas mixture comprising CO2and a hydrocarbon. In a further embodiment of the present disclosure, the hydrocarbon is CH4. In yet a further embodiment of the present disclosure, the feedmaterial is ilmenite. The ilmenite feed material may be subjected to a drying step prior to plasma treatment. In embodiments of the present disclosure, the ilmenite feed material is oven dried at temperatures ranging from about 100°C to about 120°C, over periods of time ranging from 12 to 48 hours. The composition of the reducing gas mixture may be advantageously tailored based on the metal oxide content of the feed material. In an embodiment of the present disclosure, the reducing gas mixture comprises a CO2 / hydrocarbon ratio ranging from about 1:1 to about 2:1.

[0068] EXAMPLES

[0069] The following examples are included to demonstrate preferred embodiments of the disclosure. It should be appreciated by those of skill in the art that the techniques disclosed in the examples which follow represent techniques discovered by the inventors to function well in the practice of the invention, and thus can be considered to constitute preferred modes for its practice. However, those of skill in the art should, in light of the present disclosure, appreciate that many changes can be made in the specific embodiments which are disclosed and still obtain a like or similar result without departing from the spirit and scope of the disclosure.

[0070] General Methods and Materials

[0071] CO2(99%), CH4(99%) and Ar are used as the plasma gasses in the DC thermal plasma torch. Argon (99%) is used to cool down the experimental apparatus and reduced products. MetChib – Metallurgical Services provided the Ilmenite concentrates. Additional feed materials include Al2O3(98%), Fe3O4(98%), and TiO2(99%). H2SO4(aq.) was purchased form Sigma-Aldrich. X-ray diffraction was performed on samples before and after thermal treatment to identify the crystalline phases using an X'Pert Pro MPD X-ray diffractometer from PANalytical. The starting angle was 10°, and the final angle was 70°, with a gradient of 0.05° / min. Scanning electron microscopy and Energy dispersive spectroscopy (SEM-EDS) was performed using a Hitachi S-4700 microscope equipped with a field-effect gun and cold cathode. FTIR spectra were obtained using a SpectrumTM 3 FT-IR spectrometer from PerkinElmer. BET surface area analysis was performed using an ASAP 2020 analyzer from Micromeritics.

[0072] Thermodynamic Study

[0073] To gain insight into the effects of the CO2 / CH4ratio on the thermal plasma reduction process, and to forecast the formation of titanium and iron metals, thermodynamic calculations were performed using Factsage® 8.2. It is based on theprinciple of optimizing the Gibbs free energy of all thermodynamic reactions involving selected chemical species. To cover the liquid, solid, and gas species obtained from the total reaction between CO2, CH4, and FeTiO3, and / or TiO2and / or Al2O3two databases have been chosen: FactPS (Fact pure substance database) and FToxid (oxide database for slags, glasses, ceramics, and refractories). CO2and CH4were the primary gases employed in the process, which took place at a constant pressure of 1 atm and at temperatures ranging from 0 to 5000 °C. Carbon dioxide (CO2) and methane (CH4) react to produce carbon monoxide (CO) and hydrogen gas (H2) at high temperatures. The calculations took into account the gas species formed during the thermal plasma reduction process using a CO2 / CH4gas mixture (e.g. H2O, H2, CO, OH, H, O, O3, CH, CO[-]c, O[+], HCO[+], H2[+], O[-], H[-], C2[-], H2[-], OH[-], H[+], e[-], CO2, CH4). CH4decomposition provides the source of carbon ions (C[-] and C[+]) of which C[+] deposits on the cathode surface forming a carbon layer protecting the cathode from erosion. FIG.5 illustrates the equilibrium log (mole) of a CO2 / CH4plasma mixture as a function of temperature.

[0074] FIG.6 illustrates the equilibrium log (mole) of a CO2 / CH4 plasma mixture and ilmenite FeTiO3as a function of temperature.

[0075] The production of titanium metal starts at temperatures above 1400°C, whereas the production of iron metal starts at temperatures above 600°C. The amount of iron produced increases up to a temperature of 2000°C before stabilizing. The amount of titanium produced increases after reaching a temperature of 1400°C. The ilmenite phase (FeTiO3) is stable at temperatures below 1300°C. The formation of pseudobrookite FeTi2O5occurs at temperatures above 1200°C. Carbon deposition on the cathode occurs at temperatures above 1600°C. In an embodiment of the present disclosure, the carbon deposition is a graphite deposition.

[0076] FIG.22 illustrates the equilibrium log (mole) of a CO2 / CH4plasma mixture (1:1) and ilmenite Al2O3as a function of temperature. The production of aluminum metal starts at temperatures above 1000°C.

[0077] FIG.23 illustrates the equilibrium log (mole) of a CO2 / CH4plasma mixture (1:1) and ilmenite TiO2as a function of temperature. The production of titanium metal starts at temperatures above 1400°C.

[0078] FIG.24 illustrates the equilibrium log (mole) of a CO2 / CH4plasma mixture (1:1) and ilmenite Fe3O4as a function of temperature. The production of titanium metal starts at temperatures above 600°C.

[0079] Gibbs Free Energy

[0080] The reaction to produce titanium and iron metal from natural ilmenite exhibits a negative Gibbs free energy (FIGs. 7 and 17). Increasing the temperature helps the reaction to proceed spontaneously. Hence, when the temperature increases, the ΔG become more negative and ilmenite reduction is greatly enhanced.

[0081] Temperature Variation Inside the Reactor

[0082] With reference to FIGs.8 and 21, once the reductive thermal plasma process has been initiated, the temperature inside the reactor increases rapidly to reach temperatures in excess of 700°C (CO2 / CH4plasma mixture of 1:1). During the cooling phase, the temperature inside the reactor decreases more gradually.

[0083] In an embodiment of the present disclosure, the cooling may be advantageously achieved by injecting a quench gas into the reactor. In a further embodiment of the present disclosure, the quench gas may be Ar.

[0084] XRD Analysis

[0085] The ilmenite feed material was analyzed before and after reductive thermal plasma treatment. In an embodiment of the present disclosure, the ilmenite concentrate feed material comprises substantially ilmenite as well as some magnetite. Titanium dioxide and aluminum silicate are also observed. With reference to FIGs.9, 15 and 18, after subjecting the feed material to reductive thermal plasma treatment, the presence of titanium and iron metal can be observed.

[0086] The Al2O3feed material was analyzed before and after reductive thermal plasma treatment (CO2 / CH41:1). FIG.25 reveals that the Al2O3feed material exhibits only the alumina peaks. Since the raw material was only partially reduced in the plasma reactor, some alumina peaks remained after the plasma treatment. In addition, metallic aluminum peaks also appear next to the alumina peaks, confirming the formation of aluminum.

[0087] The TiO2feed material was analyzed before and after reductive thermal plasma treatment (CO2 / CH41:1). FIG.26 reveals that before plasma treatment TiO2is in the rutile phase. After plasma treatment, additional oxidized forms of rutile appear, indicative of a partial reduction of the raw material inside the reactor. TiO2has been reduced to its metallic form in certain areas as corroborated by the presence of the titanium metal peaks.

[0088] The Fe3O4feed material was analyzed before and after reductive thermal plasma treatment (CO2 / CH41:1). FIG.27 reveals that before plasma treatment there are six prominent diffraction peaks in the X-ray diffraction pattern that correspond to the (220), (311), (400), (422), (511), and (440) crystalline planes of the magnetite phase, respectively. After plasma treatment, the magnetite was processed into iron oxide (FeO) and iron metal.

[0089] The sample consisting of a mixture of TiO2and Fe3O4was analyzed after reductive thermal plasma treatment (CO2 / CH41:1). FIG.28 reveals that Ti and Fe metals formed locally during thermal plasma treatment of the oxide mixture composed of rutile and magnetite. A distinct delineation between the iron and titanium metals could be observed. The presence of oxygen reveals that the reduction process was incomplete.

[0090] SEM Analysis

[0091] With reference to FIG.10, SEM analysis of the ilmenite concentrate following reductive thermal plasma treatment revealed that important surface modifications had taken place. In areas where iron and titanium melting had occurred, the surface has become more porous. Moreover, a metallic iron layer can be observed, deposited over a metallic titanium layer. Prior to reductive thermal plasma treatment (FIG.10a), the ilmenite concentrate, in addition to titanium and iron oxides, was comprised of impurities such as oxides of vanadium, silica, aluminum, manganese, and magnesium as well as oxygen. Moreover, the surface appears clean and smooth. Following reductive thermal plasma treatment (FIG.10b), a great many of the aforementioned impurities were advantageously removed (Table 1) and distinct metallic iron and titanium layers were observed.

[0092] Table 1: Elemental composition (wt.%) of the Ilmenite feed material before and after reductive thermal plasma treatment. Il t tr Il ttreatment

[0093] With reference to FIGs. 11 (CO2 / CH41:1) and 19 (CO2 / CH42:1), Energy Dispersive Spectroscopy (EDS) shows iron and titanium peaks next to minor impurities such as silicon and aluminum.

[0094] With reference to FIG.12, a mapping distribution of the main elements (Ti, Fe, and O) of the ilmenite concentrate feed before reductive thermal plasma treatment is illustrated. The mapping illustrates that the feed material comprises significant amounts of oxygen in the form of oxides. The iron and titanium are distributed throughout the feed material without any separation.

[0095] With reference to FIG.13, a mapping distribution of the ilmenite concentrate feed after reductive thermal plasma treatment is illustrated. The mapping illustrates that the oxygen content in the feed material has been significantly reduced. The red region highlights concentrations of iron, whereas the green region highlights concentrations of titanium. Moreover, the mapping illustrates a separation between the produced iron and titanium.

[0096] BET surface area analysis

[0097] The ilmenite’s surface (before and after reductive thermal plasma treatment) was analyzed using an ASAP 2020 analyzer from Micromeritics (Table 1). To generate an adsorption isotherm, the sample is exposed to a gas, typically nitrogen, at a variety of pressures. The BET equation (Brunauer, Emmett, and Teller) was used to extract information on the specific surface area, while the BJH (Brunauer, Joyner, and Halenda) model was used to extract information on pore size, volume, and distribution. The BET surface area of the ilmenite concentrate was reduced by 0.1147 m2 / g after reductive thermal plasma treatment, whereas the pore size increased by 54.6834 (Table 2).

[0098] Table 2: Ilmenite surface area and pore size before and after reductive thermal plasma treatment. P B B s Bpore diameter (4V / A) (nm)

[0099] Enthalpy

[0100] The use of a gas mixture comprising CO2and a hydrocarbon such as CH4advantageously provides for generating a plasma exhibiting high enthalpy and high thermal conductivity. FIG. 14 illustrates the enthalpies of a CO2 / CH4plasma torch, an argon plasma torch, and a nitrogen plasma torch. The plasma enthalpy reveals a system'sheat content. As a result, the thermodynamic properties of a plasma arc are affected by the particle density, the plasma gases, and the degree of ionization. The presence of a high electron density plasma makes the environment more energetic and reactive, allowing the plasma arc to create a rich region for chemical species activation.

[0101] FTIR Analysis

[0102] The ilmenite concentrate feed material was analyzed, before and after reductive thermal plasma treatment, using a SpectrumTM 3 FT-IR spectrometer from PerkinElmer. With reference to FIG. 16, the Ilmenite concentrate exhibits an O=C=O signal at about 2300 cm-1, a Ti-O signal at 982.97 cm-1, a Ti-O-Ti signal at 556.12 cm-1, and a Fe-O signal at about 1500 cm-1. Following reductive thermal plasma treatment, a new Ti-OH signal was observed at about 1492 cm-1resulting from ilmenite reduction at high temperatures. At about 520 cm-1, a new Fe-O bond was formed, indicative of the reduction in oxygen content of the ilmenite feed material following reductive thermal plasma treatment.

[0103] Effect of CO2 / CH4 Gas Ratio

[0104] At ambient pressure, a plasma having a CO2 / CH4ratio of 1:1 may be more stable than one having a CO2 / CH4ratio of 2:1. This is surmised to be due, at least in part, to the latter's potential to produce a hotter, more reactive plasma with a greater concentration of reactive species. Moreover, increasing the amount of CH4relative to CO2increases the reducing power of the plasma gas. FIG.20 illustrates the power variation over time in a spouted bed reactor.

[0105] EXAMPLE 1 – Production of metallic Fe and Ti

[0106] An ilmenite concentrate provided by MetChib - Metallurgical Services (Quebec, Canada) was used in this Example. In an embodiment, the ilmenite concentrate was composed of Fe2O3(50.88%), TiO2(42.30%), SiO2(3.77%), Al2O3(2.30%) and other oxides. The particle size range was between 100-200 µm. A steady plasma arc exhibiting high enthalpy and thermal conductivity was generated using a 50 kW DC thermal plasma torch and the two greenhouse gases, carbon dioxide (CO2) and methane (CH4). Thermocouples were used to monitor the inlet and outlet temperatures of the reactor in order to maintain a desired temperature gradient for the reduced material. A fluidized bed reactor was used to smelt the ilmenite concentrate. The 50 kW DC thermal plasma torch’s reduction power was modulated by adjusting the CO2 / CH4gas ratio to 1:1. The experimental apparatus was equipped with a spouted bed reactor comprising a bottomcone in direct contact with the plasma. The current and voltage of the plasma torch were kept constant at 252 amps and 150 V respectively. The ilmenite concentrate was heated until the section closest to the torch turned red. In an embodiment of the present disclosure, the ilmenite material was heated for about 3 minutes. The pressure within the torch is maintained close to atmospheric pressure. An argon flux was pumped through the reactor in order to prevent the molten cone of reduced ilmenite product from falling into the plasma torch. The walls of the reactor are cooled using cold water and the reduced ilmenite product was cooled using a flow of argon. Exit gases from the reactor were analyzed using a mass spectrometer.

[0107] EXAMPLE 2 - Production of metallic Fe and Ti

[0108] An ilmenite concentrate provided by Metchib - Metallurgical Services (Quebec, Canada) was used in this Example. The particle size range was between 50-150 µm. A steady plasma arc was generated using a 50 kW DC thermal plasma torch and the two greenhouse gases, carbon dioxide (CO2) and methane (CH4). The plasma torch’s reduction power was modulated by adjusting the CO2 / CH4gas ratio to 1:1. The current was maintained between 250-260 amps and the voltage at 152 V. The temperature within the reactor reached 760°C. The reduced ilmenite product was cooled using a flow of argon.

[0109] EXAMPLE 3 - Production of metallic Fe and Ti

[0110] An ilmenite concentrate provided by Metchib - Metallurgical Services (Quebec, Canada) was used in this Example. A steady plasma arc was generated using a 50 kW DC thermal plasma torch and the two greenhouse gases, carbon dioxide (CO2) and methane (CH4). The plasma torch’s reduction power was modulated by adjusting the CO2 / CH4gas ratio to 1:2. The current and voltage of the plasma torch were kept constant at 250 amps and 152 V respectively. The temperature within the reactor reached 690°C. The reduced ilmenite product was cooled using a flow of argon.

[0111] EXAMPLE 4 - Production of metallic Fe and Ti

[0112] An ilmenite concentrate provided by Metchib - Metallurgical Services (Quebec, Canada) was used in this Example. The particle size range was between 80-250 µm. A steady plasma arc was generated using a 50 kW DC thermal plasma torch and the two greenhouse gases, carbon dioxide (CO2) and methane (CH4). The plasma torch’s reduction power was modulated by adjusting the CO2 / CH4gas ratio to 1:1. The currentand voltage of the plasma torch were kept constant at 252 amps and 152 V respectively. The reduced ilmenite product was cooled using a flow of argon.

[0113] EXAMPLE 5 - Production of metallic Fe

[0114] A magnetite (Fe3O4) sample was used in this Example. The particle size range was between 100-200 µm. A steady plasma arc was generated using a 50 kW DC thermal plasma torch and the two greenhouse gases, carbon dioxide (CO2) and methane (CH4). The plasma torch’s reduction power was modulated by adjusting the CO2 / CH4gas ratio to 1:1. The temperature within the reactor reached 700°C. The reduced magnetite product was cooled using a flow of argon.

[0115] EXAMPLE 6 - Production of metallic Ti

[0116] A rutile (TiO2; 99%) sample was used in this Example. A steady plasma arc was generated using a 50 kW DC thermal plasma torch and the two greenhouse gases, carbon dioxide (CO2) and methane (CH4). The plasma torch’s reduction power was modulated by adjusting the CO2 / CH4gas ratio to 1:1. The temperature within the reactor reached 650°C. The reduced rutile product was cooled using a flow of argon.

[0117] EXAMPLE 7 - Production of metallic Fe and Ti

[0118] A 300g mixture of iron oxide and TiO2was used in this Example. A steady plasma arc was generated using a 50 kW DC thermal plasma torch and the two greenhouse gases, carbon dioxide (CO2) and methane (CH4). The plasma torch’s reduction power was modulated by adjusting the CO2 / CH4gas ratio to 1:1.22. The current and voltage of the plasma torch were kept constant at 251 amps and 145 V respectively. The reduced product was cooled using a flow of argon.

[0119] EXAMPLE 8 - Production of metallic Al

[0120] An alumina (Al2O3; 98%) sample was used in this Example. The particle size range was between 100-200 µm. A steady plasma arc was generated using a 50 kW DC thermal plasma torch and the two greenhouse gases, carbon dioxide (CO2) and methane (CH4). The plasma torch’s reduction power was modulated by adjusting the CO2 / CH4gas ratio to 1:1. The current and voltage of the plasma torch were kept constant at 252 amps and 150 V respectively. The temperature within the reactor reached 700°C. The reduced product was cooled using a flow of argon.

[0121] EXAMPLE 9 - Plasma Parameters for Reduction of Various Oxides - Production of metallic Al, Ti, Fe

[0122] Selected plasma parameters for the reduction of AlO3, TiO2, Fe3O4and a mixture composed of TiO2and Fe3O4are illustrated in Table 3. Material Initial CO2 / CH4Time Temp. Pressure Voltage Current T 1 T 2 T 3 T 4

[0123] All of the processes disclosed and claimed herein can be made and executed without undue experimentation in light of the present disclosure. While the processes of this disclosure have been described in terms of preferred embodiments, it will be apparent to those of skill in the art that variations may be applied to the processes and in the steps or in the sequence of steps of the processes described herein without departing from the concept, spirit, and scope of the disclosure. More specifically, it will be apparent that certain process parameters and / or reagents which are chemically related may be substituted for the reagents described herein while the same or similar results would be achieved. All such similar substitutes and modifications apparent to those skilled in the art are deemed to be within the spirit, scope and concept of the disclosure as defined by the appended claims.

Claims

CLAIMS 1. A process for metal oxide reduction, the process comprising: producing a plasma to bring the metal oxide to a reaction temperature ranging from about 500°C to about 5000°C; and reacting the metal oxide at the reaction temperature ranging from about 500°C to about 5000°C with a reducing gas mixture comprising CO2and a hydrocarbon to produce a reduced metal oxide.

2. The process of claim 1, further comprising cooling the reduced metal oxide to a temperature ranging from about 25°C to about 500°C by injecting a quench gas.

3. The process of claim 1 or 2, further comprising collecting the reduced metal oxide.

4. The process of any one of claims 1 to 3, wherein reacting the metal oxide with the reducing gas mixture comprises injecting the reducing gas mixture into the plasma.

5. The process of any one of claims 1 to 4, wherein the reducing gas mixture comprises a CO2 / hydrocarbon ratio ranging from about 2:1 to about 1:

4.

6. The process of any one of claims 1 to 5, wherein the hydrocarbon is at least one of natural gas, CH4, C2H6, and C3H8.

7. The process of claim 6, wherein the hydrocarbon is CH4.

8. The process of any one of claims 1 to 7, wherein the metal oxide is comprised in an ore material, a concentrate or a mining residue.

9. The process of claim 8, wherein the metal oxide is at least one of Li2O, MgO, Al2O3, TiO2, V2O5, Cr2O3, MnO2, Fe3O4, CoO, NiO, CuO, ZnO, Ga2O3, Y2O3, ZrO2, Nb2O5, Mo2O3, Tc2O7, RuO2, Rh2O3, PdO, Au2O, CdO, In2O3, SnO, La2O3, HfO2, Ta2O5, WO2, Re2O7, OsO4, IrO2, PtO2, Au2O3, Tl2O3, CeO2, Nd2O3, Pr6O11, Sm2O3, Gd2O3, Dy2O3, Yb2O3, Er2O3and mixtures thereof.

10. The process of claim 8, wherein the ore material comprises ilmenite.

11. The process of any one of claims 1 to 10, wherein the plasma is produced using a readily ionizable working gas.

12. The process of claim 11, wherein the working gas comprises at least one of He, Ar and N2.

13. The process of any one of claims 1 to 12, wherein the plasma is produced using a DC thermal plasma torch, an alternating current (AC) thermal plasma torch, a radio- frequency (RF) thermal plasma torch, an induction thermal plasma torch, or a microwave plasma.

14. The process of claim 13, wherein the DC thermal plasma torch is a transferred arc plasma torch or a non-transferred arc plasma torch.

15. The process of claim 13 or 14, wherein the DC thermal plasma torch comprises an anode and a cathode, and wherein a carbon layer is deposited on the cathode surface during operation.

16. The process of claim 15, further comprising adjusting the electric current through the cathode and anode based on post-plasma mixture composition analysis.

17. The process of any one of claims 1 to 16, further comprising adjusting a composition of the reducing gas mixture based on post-plasma mixture composition analysis.

18. The process of any one of claims 1 to 17, further comprising adjusting a rate of injection of the reducing gas mixture based on post-plasma mixture composition analysis.

19. The process of any one of claims 1 to 18, wherein the reduced metal oxide is at least one of Li, Mg, Al, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, In, Sn, La, Hf, Ta, W, Re, Os, Ir, Pt, Au, Ce, Nd, Pr, Sm, Gd, Dy, Yb, Er and Tl.

20. The process of any one of claims 1 to 19, further comprising leaching the reduced metal oxide in an acidic solution thereby producing a pregnant solution.

21. The process of claim 20, wherein the leaching is performed at a temperature ranging between 20˚C and 300˚C.

22. The process of claim 20 or 21, wherein the acidic solution is at least one of a sulfuric acid solution, a hydrochloric acid solution, a nitric acid solution, a carbonic acid solution, an oxalic acid solution, or a combination of any thereof.

23. The process of claim 22, wherein the acidic solution is a sulfuric acid solution.

24. The process of claim 23, wherein the sulfuric acid solution comprises a mass percentage from about 5 wt.% H2SO4to about 100 wt.% H2SO4.

25. The process of claim 24, wherein the sulfuric acid solution comprises a mass percentage from about 15 wt.% H2SO4to about 80 wt.% H2SO4.

26. The process of claim 24 or 25, wherein the sulfuric acid solution has a mass percentage of about 30 wt.% H2SO4.

27. The process of any one of claims 23 to 26, wherein the sulfuric acid leaching is performed over a period ranging from about 30 minutes to about 3 hours.

28. The process of claim 27, wherein the sulfuric acid leaching is performed over a period ranging from about 1 hour to about 2.5 hours.

29. The process of claim 27 or 28, wherein the sulfuric acid leaching is performed over a period of about 1.5 hours.

30. A process for metal oxide reduction, the process comprising: producing a reducing plasma to bring the metal oxide to a reaction temperature ranging from about 500°C to about 5000°C; and reacting the metal oxide at the reaction temperature ranging from about 500°C to about 5000°C with the reducing plasma to produce a reduced metal oxide.

31. The process of claim 30, further comprising cooling the reduced metal oxide to a temperature ranging from about 25°C to about 500°C by injecting a quench gas.

32. The process of claim 30 or 31, further comprising collecting the reduced metal oxide.

33. The process of any one of claims 30 to 32, wherein the reducing plasma is produced using a reducing gas mixture comprising CO2and a hydrocarbon.

34. The process of any one of claims 30 to 33, wherein the reducing gas mixture comprises a CO2 / hydrocarbon ratio ranging from about 2:1 to about 1:

4.

35. The process of any one of claims 30 to 34, wherein the hydrocarbon is at least one of natural gas, CH4, C2H6, and C3H8.

36. The process of claim 35, wherein the hydrocarbon is CH4.

37. The process of any one of claims 30 to 36, wherein the metal oxide is comprised in an ore material, a concentrate or a mining residue.

38. The process of claim 37, wherein the metal oxide is at least one of Li2O, MgO, Al2O3, TiO2, V2O5, Cr2O3, MnO2, Fe3O4, CoO, NiO, CuO, ZnO, Ga2O3, Y2O3, ZrO2, Nb2O5, Mo2O3, Tc2O7, RuO2, Rh2O3, PdO, Au2O, CdO, In2O3, SnO, La2O3, HfO2, Ta2O5, WO2, Re2O7, OsO4, IrO2, PtO2, Au2O3, Tl2O3, CeO2, Nd2O3, Pr6O11, Sm2O3, Gd2O3, Dy2O3, Yb2O3, Er2O3and mixtures thereof.

39. The process of claim 37, wherein the ore material comprises ilmenite.

40. The process of any one of claims 30 to 39, wherein the plasma is produced using a DC thermal plasma torch, an alternating current (AC) thermal plasma torch, a radio- frequency (RF) thermal plasma torch, an induction thermal plasma torch, or a microwave plasma.

41. The process of claim 40, wherein the DC thermal plasma torch is a transferred arc plasma torch or a non-transferred arc plasma torch.

42. The process of claim 40 or 41, wherein the DC thermal plasma torch comprises an anode and a cathode, and wherein a carbon layer is deposited on the cathode surface during operation.

43. The process of claim 42, further comprising adjusting the electric current through the cathode and anode based on post-plasma mixture composition analysis.

44. The process of any one of claims 30 to 43, further comprising adjusting a composition of the reducing gas mixture based on post-plasma mixture composition analysis.

45. The process of any one of claims 30 to 44, further comprising adjusting a rate of injection of the reducing gas mixture based on post-plasma mixture composition analysis.

46. The process of any one of claims 30 to 45, wherein the reduced metal oxide is at least one of Li, Mg, Al, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, In, Sn, La, Hf, Ta, W, Re, Os, Ir, Pt, Au, Ce, Nd, Pr, Sm, Gd, Dy, Yb, Er and Tl.

47. The process of any one of claims 30 to 46, further comprising leaching the reduced metal oxide in an acidic solution thereby producing a pregnant solution.

48. The process of claim 47, wherein the leaching is performed at a temperature ranging between 20˚C and 300˚C.

49. The process of claim 47 or 48, wherein the acidic solution is at least one of a sulfuric acid solution, a hydrochloric acid solution, a nitric acid solution, a carbonic acid solution, an oxalic acid solution, or a combination of any thereof.

50. The process of claim 49, wherein the acidic solution is a sulfuric acid solution.

51. The process of claim 50, wherein the sulfuric acid solution comprises a mass percentage from about 5 wt.% H2SO4to about 100 wt.% H2SO4.

52. The process of claim 51, wherein the sulfuric acid solution comprises a mass percentage from about 15 wt.% H2SO4to about 80 wt.% H2SO4.

53. The process of claim 51 or 52, wherein the sulfuric acid solution has a mass percentage of about 30 wt.% H2SO4.

54. The process of any one of claims 50 to 53, wherein the sulfuric acid leaching is performed over a period ranging from about 30 minutes to about 3 hours.

55. The process of claim 54, wherein the sulfuric acid leaching is performed over a period ranging from about 1 hour to about 2.5 hours.

56. The process of claim 54 or 55, wherein the sulfuric acid leaching is performed over a period of about 1.5 hours.

57. The process of claim 2 or 31, wherein the quench gas comprises Ar.

58. A process for the production of a metal from its oxide ore, the process comprising: producing a plasma to bring the oxide ore to a reaction temperature ranging from about 500°C to about 5000°C; and reacting the oxide ore at the reaction temperature ranging from about 500°C to about 5000°C with a reducing gas mixture comprising CO2and a hydrocarbon to produce a reduced oxide ore.

59. The process of claim 58, further comprising cooling the reduced oxide or to a temperature ranging from about 25°C to about 500°C by injecting a quench gas.

60. The process of claim 58 or 59, further comprising collecting the reduced oxide ore.

61. The process of any one of claims 58 to 60, wherein reacting the oxide ore with the reducing gas mixture comprises injecting the reducing gas mixture into the plasma.

62. The process of any one of claims 58 to 61, wherein the reducing gas mixture comprises a CO2 / hydrocarbon ratio ranging from about 2:1 to about 1:

4.

63. The process of any one of claims 58 to 62, wherein the hydrocarbon is at least one of natural gas, CH4, C2H6, and C3H8.

64. The process of claim 63, wherein the hydrocarbon is CH4.

65. The process of any one of claims 58 to 64, wherein the oxide ore comprises at least one metal oxide including Li2O, MgO, Al2O3, TiO2, V2O5, Cr2O3, MnO2, Fe3O4, CoO, NiO, CuO, ZnO, Ga2O3, Y2O3, ZrO2, Nb2O5, Mo2O3, Tc2O7, RuO2, Rh2O3, PdO, Au2O, CdO, In2O3, SnO, La2O3, HfO2, Ta2O5, WO2, Re2O7, OsO4, IrO2, PtO2, Au2O3, Tl2O3, CeO2, Nd2O3, Pr6O11, Sm2O3, Gd2O3, Dy2O3, Yb2O3, Er2O3and mixtures thereof.

66. The process of claim 65, wherein the oxide ore comprises ilmenite.

67. The process of any one of claims 58 to 66, wherein the plasma is produced using a readily ionizable working gas.

68. The process of claim 67, wherein the working gas comprises at least one of He, Ar and N2.

69. The process of any one of claims 58 to 68, wherein the plasma is produced using a DC thermal plasma torch, an alternating current (AC) thermal plasma torch, a radio- frequency (RF) thermal plasma torch, an induction thermal plasma torch, or a microwave plasma.

70. The process of claim 69, wherein the DC thermal plasma torch is a transferred arc plasma torch or a non-transferred arc plasma torch.

71. The process of claim 69 or 70, wherein the DC thermal plasma torch comprises an anode and a cathode, and wherein a carbon layer is deposited on the cathode surface during operation.

72. The process of claim 71, further comprising adjusting the electric current through the cathode and anode based on post-plasma mixture composition analysis.

73. The process of any one of claims 58 to 72, further comprising adjusting a composition of the reducing gas mixture based on post-plasma mixture composition analysis.

74. The process of any one of claims 58 to 73, further comprising adjusting a rate of injection of the reducing gas mixture based on post-plasma mixture composition analysis.

75. The process of any one of claims 58 to 74, wherein the metal is at least one of Li, Mg, Al, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, In, Sn, La, Hf, Ta, W, Re, Os, Ir, Pt, Au, Ce, Nd, Pr, Sm, Gd, Dy, Yb, Er and Tl.

76. The process of any one of claims 58 to 75, further comprising leaching the reduced oxide ore in an acidic solution thereby producing a pregnant solution.

77. The process of claim 76, wherein the leaching is performed at a temperature ranging between 20˚C and 300˚C.

78. The process of claim 76 or 77, wherein the acidic solution is at least one of a sulfuric acid solution, a hydrochloric acid solution, a nitric acid solution, a carbonic acid solution, an oxalic acid solution, or a combination of any thereof.

79. The process of claim 78, wherein the acidic solution is a sulfuric acid solution.

80. The process of claim 79, wherein the sulfuric acid solution comprises a mass percentage from about 5 wt.% H2SO4to about 100 wt.% H2SO4.

81. The process of claim 80, wherein the sulfuric acid solution comprises a mass percentage from about 15 wt.% H2SO4to about 80 wt.% H2SO4.

82. The process of claim 80 or 81, wherein the sulfuric acid solution has a mass percentage of about 30 wt.% H2SO4.

83. The process of any one of claims 79 to 82, wherein the sulfuric acid leaching is performed over a period ranging from about 30 minutes to about 3 hours.

84. The process of claim 83, wherein the sulfuric acid leaching is performed over a period ranging from about 1 hour to about 2.5 hours.

85. The process of claim 83 or 84, wherein the sulfuric acid leaching is performed over a period of about 1.5 hours.

86. A process for metal oxide reduction, the process comprising: determining the constituents of a feed material from which one or more metals are to be extracted; using process simulation and / or modeling software to model a plasma arc reaction for the feed material comprising the one or more metals as metal oxides and a reducing agent comprising CO2and a hydrocarbon; feeding the feed material into a thermal plasma torch producing a material comprising reduced metal oxides.

87. The process of claim 86, further comprising: producing a plasma to bring the feed material to a reaction temperature ranging from about 500°C to about 5000°C; reacting the feed material at the reaction temperature ranging from about 500°C to about 5000°C with the reducing agent producing a reduced metal oxide; and cooling the reduced metal oxides to a temperature ranging from about 25°C to about 500°C by injecting a quench gas.

88. The process of claim 86 or 87, further comprising collecting the reduced metal oxides.

89. The process of any one of claims 86 to 88, wherein reacting the feed material with the reducing agent comprises injecting the reducing agent into the plasma.

90. The process of any one of claims 86 to 89, wherein the reducing agent comprises a CO2 / hydrocarbon ratio ranging from about 2:1 to about 1:

4.

91. The process of any one of claims 86 to 90, wherein the hydrocarbon is at least one of natural gas, CH4, C2H6, and C3H8.

92. The process of claim 91, wherein the hydrocarbon is CH4.

93. The process of any one of claims 86 to 92, wherein the feed material is an ore material, a concentrate or a mining residue.

94. The process of any one of claims 86 to 93, wherein the metal oxide is at least one of Li2O, MgO, Al2O3, TiO2, V2O5, Cr2O3, MnO2, Fe3O4, CoO, NiO, CuO, ZnO, Ga2O3, Y2O3, ZrO2, Nb2O5, Mo2O3, Tc2O7, RuO2, Rh2O3, PdO, Au2O, CdO, In2O3, SnO, La2O3, HfO2, Ta2O5, WO2, Re2O7, OsO4, IrO2, PtO2, Au2O3, Tl2O3, CeO2, Nd2O3, Pr6O11, Sm2O3, Gd2O3, Dy2O3, Yb2O3, Er2O3and mixtures thereof.

95. The process of claim 86, wherein the feed material comprises ilmenite.

96. The process of claim 87, wherein the plasma is produced using a readily ionizable working gas.

97. The process of claim 96, wherein the working gas comprises at least one of He, Ar and N2.

98. The process of any one of claims 86 to 98, wherein the thermal plasma torch comprises a DC thermal plasma torch, an alternating current (AC) thermal plasma torch, a radio-frequency (RF) thermal plasma torch, an induction thermal plasma torch, or a microwave plasma.

99. The process of claim 98, wherein the DC thermal plasma torch is a transferred arc plasma torch or a non-transferred arc plasma torch.

100. The process of claim 98 or 99, wherein the DC thermal plasma torch comprises an anode and a cathode, and wherein a carbon layer is deposited on the cathode surface during operation.

101. The process of claim 100, further comprising adjusting the electric current through the cathode and anode based on post-plasma mixture composition analysis.

102. The process of any one of claims 86 to 101, further comprising adjusting a composition of the reducing agent based on post-plasma mixture composition analysis.

103. The process of any one of claims 86 to 102, further comprising adjusting a rate of injection of the reducing agent based on post-plasma mixture composition analysis.

104. The process of any one of claims 86 to 103, wherein the reduced metal oxide is at least one of Li, Mg, Al, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, In, Sn, La, Hf, Ta, W, Re, Os, Ir, Pt, Au, Ce, Nd, Pr, Sm, Gd, Dy, Yb, Er and Tl.

105. The process of any one of claims 86 to 104, further comprising leaching the reduced metal oxides in an acidic solution thereby producing a pregnant solution.

106. The process of claim 105, wherein the leaching is performed at a temperature ranging between 20˚C and 300˚C.

107. The process of claim 105 or 106, wherein the acidic solution is at least one of a sulfuric acid solution, a hydrochloric acid solution, a nitric acid solution, a carbonic acid solution, an oxalic acid solution, or a combination of any thereof.

108. The process of claim 107, wherein the acidic solution is a sulfuric acid solution.

109. The process of claim 108, wherein the sulfuric acid solution comprises a mass percentage from about 5 wt.% H2SO4to about 100 wt.% H2SO4.

110. The process of claim 109, wherein the sulfuric acid solution comprises a mass percentage from about 15 wt.% H2SO4to about 80 wt.% H2SO4.

111. The process of claim 109 or 110, wherein the sulfuric acid solution has a mass percentage of about 30 wt.% H2SO4.

112. The process of any one of claims 108 to 111, wherein the sulfuric acid leaching is performed over a period ranging from about 30 minutes to about 3 hours.

113. The process of claim 112, wherein the sulfuric acid leaching is performed over a period ranging from about 1 hour to about 2.5 hours.

114. The process of claim 112 or 113, wherein the sulfuric acid leaching is performed over a period of about 1.5 hours.

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