WO2014140700A1

WO2014140700A1 - Methods of producing vanadium boride and uses thereof

Info

Publication number: WO2014140700A1
Application number: PCT/IB2013/054119
Authority: WO
Inventors: Nilanjan DEB
Original assignee: University of Calcutta
Current assignee: University of Calcutta
Priority date: 2013-03-14
Filing date: 2013-05-20
Publication date: 2014-09-18
Anticipated expiration: 2015-09-14
Also published as: CN105228955B; CN105228955A

Abstract

Described herein are methods of producing metal borides including, but not limited to vanadium boride from metal ores and iron slag. Also disclosed are methods of producing vanadium boride in situ from titaniferous magnetite ore or iron slag and uses for vanadium boride.

Description

METHOD OF PRODUCING VANADIUM B PRIDE AND USES THEREOF

BACKGROUND

[0001] Electrochemical energy represents a dependable energy source and has utility as a replacement for depleting oil resources. Metal borides can be used to create batteries or fuel cells, which can be alternative energy sources to oil resources. Electrochemical energy storage technology with multi-electron oxidation of metal borides such as vanadium boride can be promising to replace existing batteries that are based on single electron charge storage. The multiple electron oxidation of a vanadium boride anode coupled with a carbon air cathode can provide extraordinary electrochemical energy storage capacities due to its multi- electron charge storage capabilities. Vanadium can be found in vanadium-bearing ores, such as titaniferous magnetite ore, where the vanadium pentoxide content may range from about 0.63 weight percent to about 1.38 weight percent. Vanadium can also be found in iron slag after smelting, where the vanadium pentoxide content may range from about 6 weight percent to about 25 weight percent. It will therefore be desirable to provide a simple method of producing vanadium boride directly from a vanadium-bearing ore or slag, and it will also be desirable that the method can be performed under ambient temperatures and pressures. SUMMARY

[0002] Embodiments described herein are directed to methods of producing metal borides, including, but are not limited to, vanadium boride. In an embodiment, a method of producing vanadium boride may comprise reducing vanadium pentoxide contained in vanadium-bearing ore, vanadium-bearing iron slag, or both, to produce vanadium (III) oxide; reducing the vanadium (III) oxide to vanadium (II) oxide; forming a vanadium nanoparticle; and forming vanadium boride from the vanadium nanoparticle.

[0003] In an embodiment, a method of producing vanadium boride may comprise: reducing vanadium pentoxide contained in vanadium-bearing ore, vanadium-bearing iron slag, or both, to produce a vanadium nanoparticle; and forming vanadium boride from the vanadium nanoparticle.

[0004] In an embodiment, a method of producing a metal boride may comprise: reducing a metal oxide contained in metal bearing ore, metal bearing iron slag, or both, to produce a metal nanoparticle; and forming a metal boride from the metal nanoparticle. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] Figure 1 depicts the X-ray diffraction (XRD) of vanadium boride produced from vanadium chloride.

[0006] Figure 2 depicts the X-ray diffraction (XRD) of vanadium boride produced from vanadium bearing magnetite ore.

[0007] Figure 3 depicts the X-ray diffraction (XRD) of vanadium boride produced from vanadium bearing iron slag.

[0008] Figure 4 depicts the Fourier transform infrared spectroscopy (FTIR) of vanadium boride produced from vanadium chloride.

[0009] Figure 5 depicts the Fourier transform infrared spectroscopy (FTIR) of vanadium boride produced from vanadium bearing magnetite ore.

[0010] Figure 6 depicts the Fourier transform infrared spectroscopy (FTIR) of vanadium boride produced from vanadium bearing iron slag.

[0011] Figure 7 depicts the in-situ formation of vanadium boride crystals from vanadium bearing iron slag

[0012] Figure 8 depicts various shapes and sizes of vanadium boride crystals produced by the methods described herein.

[0013] Figure 9 depicts iron oxide coated vanadium boride crystals.

DETAILED DESCRIPTION

[0014] Embodiments described herein are directed to methods of producing metal borides including, but are not limited to, vanadium boride from metal-containing ores and iron slag. The metal oxides produced by the methods described herein can have multiple applications including, but are not limited to, their uses in batteries. In the various methods, components may be added in a single batch, in multiple portions, or continuously.

[0015] Methods of producing vanadium boride (VB?) [0016] In an embodiment, a method of producing vanadium boride may include: reducing vanadium pentoxide contained in vanadium-bearing ore, vanadium-bearing iron slag, or both, to produce vanadium (III) oxide; reducing the vanadium (III) oxide to vanadium (II) oxide; forming a vanadium nanoparticle; and forming vanadium boride from the vanadium nanoparticle. [0017] In some embodiments, the vanadium-bearing ore may generally be any vanadium-bearing ore, and for example can be titaniferous magnetite ore, oxidized patronite, vanadinite, carnotite, or a combination thereof. Vanadium is naturally found in a number of vanadium-bearing ores in the form of vanadium pentoxide (V₂O₅). For example, the amount of vanadium pentoxide in titaniferous magnetite ore may often range from about 0.63% to about 1.38% by weight, and the amount of vanadium pentoxide in iron slag after smelting may often range from about 6% to about 25% by weight. The ore and slag may generally contain any concentration of vanadium and vanadium pentoxide. In some embodiments, the vanadium-bearing ore may contain less than about 2% vanadium pentoxide by weight. In some embodiments, the vanadium-bearing iron slag may contain less than about 25% vanadium pentoxide by weight.

[0018] The reducing of the vanadium pentoxide to vanadium (III) oxide can be performed using a catalytic reduction process or a non-catalytic reduction process. In some embodiments, reducing the vanadium pentoxide may include contacting the vanadium pentoxide contained in a mixture or solution of the vanadium-bearing ore, vanadium-bearing iron slag, or both, with vanadium tetrachloride. The vanadium tetrachloride may function as a catalytic reagent in the catalytic reduction process.

[0019] The vanadium tetrachloride may be obtained commercially, or can be prepared by various methods, including being prepared by combining vanadium pentoxide with hydrochloric acid. [0020] The vanadium-bearing ore, the vanadium-bearing iron slag, or both, may be combined with at least one solvent to form a mixture or solution before contacting with the vanadium tetrachloride. Alternatively, the solvent may be added after contacting the vanadium pentoxide with the vanadium tetrachloride. In some embodiments, reducing the vanadium pentoxide may further include contacting the vanadium pentoxide and the vanadium tetrachloride with at least one solvent. To prepare the solution, the vanadium- bearing ore, vanadium-bearing iron slag or both, may be milled or otherwise processed into a powder followed by mixing with at least one solvent prior to being used in the methods described herein. In some embodiments, the finer the vanadium-bearing ore, vanadium- bearing iron slag or both, the greater the reactivity. In some embodiments, the solvent may be water, ethanol, isopropanol, methanol, or a combination thereof. In some embodiments, the solvent may be a mixture of at least two of water, ethanol, isopropanol, and methanol. In some embodiments, the solvent may be a mixture of water and ethanol. In some embodiments, the water and ethanol may be present in the mixture in a ratio of about 1 to 2 by volume. For example, the mixture or solution may be formed by grinding titaniferous magnetite ore to a powder and mixing with deionized water to produce a 10% titaniferous magnetite ore solution by weight. In another example, iron slag may be ground to a powder and mixed with deionized water to produce a 10% iron slag solution by weight. Accordingly, the titaniferous magnetite ore solution, and the iron slag solution can be made up of up to about 25% w/v of titaniferous magnetite ore, and iron slag, respectively. In some embodiments, the titaniferous magnetite ore solution, and the iron slag solution can be made up of about 1 to about 10%> titaniferous magnetite ore, and iron slag, respectively. In some embodiments, the titaniferous magnetite ore solution, and the iron slag solution can be made up of about 1 to about 25% titaniferous magnetite ore, and iron slag, respectively. In some embodiments, the titaniferous magnetite ore solution, and the iron slag solution can be made up of greater than 25% titaniferous magnetite ore, and iron slag, respectively. These ratios, amounts, concentrations, solvents, and materials can be varied. [0021] In some embodiments, the mixture or solution of vanadium-bearing ore, vanadium-bearing iron slag or both, in the solvent, and the vanadium tetrachloride, may be contacted at generally any ratio, including, for example a ratio of about 2 to 1 (v/v), to about 20 to 1 (v/v). In some embodiments, the solution and the vanadium tetrachloride may be contacted at a ratio of about 2 to 1 (v/v), about 5 to 1 (v/v), about 10 to 1 (v/v), about 15 to 1 (v/v), about 20 to 1 (v/v), and any ratio between any two of these values.

[0022] The reducing of the vanadium pentoxide to vanadium (III) oxide may optionally further include adding at least one reducing agent after contacting the vanadium pentoxide with vanadium tetrachloride. The reducing agent can be any compound that is capable of releasing hydrogen (¾) and providing the boron component in the vanadium boride. In some embodiments, reducing the vanadium pentoxide may further include adding a borohydride compound, a borate compound with hydrogen (¾), or both, after contacting the vanadium pentoxide with the vanadium tetrachloride. In some embodiments, the borohydride compound may be sodium borohydride, lithium borohydride, sodium cyanoborohydride, potassium borohydride, lithium triethylborohydride, or a combination thereof. In some embodiments, the borate compound may be sodium metaborate, sodium borate, lithium metaborate, lithium borate, lithium tetraborate, or a combination thereof. [0023] The reducing of the vanadium (III) oxide to vanadium (II) oxide can be performed as a catalytic reduction process or as a non-catalytic reduction process. The catalytic reagent in the catalytic reduction process may be vanadium tetrachloride. The vanadium tetrachloride may be from an excess of the catalytic reagent that was previously contacted with the vanadium pentoxide, or can be additionally introduced. The reducing of the vanadium (III) oxide to vanadium (II) oxide can also include contacting the vanadium (III) oxide with at least one reducing agent. The reducing agent can be any compound that is capable of releasing hydrogen (H₂) and providing the boron component in the vanadium boride. In some embodiments, reducing the vanadium (III) oxide to vanadium (II) oxide may include contacting the vanadium (III) oxide with a borohydride compound, a borate compound and hydrogen (H₂), or both. In some embodiments, the borate compound may be sodium metaborate, sodium borate, lithium metaborate, lithium borate, lithium tetraborate, or a combination thereof. In some embodiments, the borohydride compound may be sodium borohydride, lithium borohydride, sodium cyanoborohydride, potassium borohydride, lithium triethylborohydride, or a combination thereof. Where the reducing agent is the borate compound and hydrogen (H₂), the borate compound and hydrogen (H₂) may be additionally introduced, or may formed in situ from an excess of the borohydride compound used in the reducing of the vanadium pentoxide to vanadium (III) oxide. In some embodiments, reducing the vanadium (III) oxide to vanadium (II) oxide may further include contacting the vanadium (III) oxide with hydrochloric acid, chlorine (Cl₂), or both. The hydrochloric acid and chlorine (Cl₂) may be additionally introduced or may be formed in situ from the reducing of the vanadium pentoxide to vanadium (III) oxide. In some embodiments, reducing the vanadium (III) oxide to vanadium (II) oxide may include contacting the vanadium (III) oxide with sodium metaborate, hydrochloric acid, chlorine (Cl₂), and hydrogen (H₂).

[0024] The forming of a vanadium nanoparticle from vanadium (II) oxide may include contacting the vanadium (II) oxide with at least one reducing agent. The reducing agent can be any compound that is capable of releasing hydrogen (H₂) and providing the boron component in the vanadium boride. In some embodiments, forming a vanadium nanoparticle may include contacting the vanadium (II) oxide with a borate compound and hydrogen (H₂), a borohydride compound, or both. In some embodiments, the borate compound may be sodium metaborate, sodium borate, lithium metaborate, lithium borate, lithium tetraborate, or a combination thereof. In some embodiments, the borohydride compound may be sodium borohydride, lithium borohydride, sodium cyanoborohydride, potassium borohydride, lithium triethylborohydride, or a combination thereof. Where the reducing agent is the borate compound and hydrogen (¾), the borate compound and hydrogen (H₂) may be additionally introduced, or may formed in situ from an excess of the borohydride compound used in the reducing of the vanadium pentoxide to vanadium (III) oxide, from the reducing of the vanadium (III) oxide to vanadium (II) oxide, or both. In some embodiments, forming the vanadium nanoparticle may further include contacting the vanadium (II) oxide with hydrochloric acid, chlorine (Cl₂), or both. The hydrochloric acid and chlorine (Cl₂) may be additionally introduced or may be formed in situ from the reducing of the vanadium pentoxide to vanadium (III) oxide, the reducing of the vanadium (III) oxide to vanadium (II) oxide, or both. In some embodiments, forming the vanadium nanoparticle may include contacting the vanadium (II) oxide with sodium metaborate, hydrochloric acid, chlorine (Cl₂), and hydrogen (H₂).

[0025] In some embodiments, forming the vanadium boride from the vanadium nanoparticle may include contacting the vanadium nanoparticle with boric acid. In some embodiments, forming the vanadium boride from the vanadium nanoparticle may further include contacting the vanadium nanoparticle with hydrogen (H₂). In some embodiments, forming vanadium boride from the vanadium nanoparticle may include contacting the vanadium boride nanoparticle with boric acid and hydrogen (H₂). The boric acid and the hydrogen (H₂) may be additionally introduced, or may be formed in situ from the reduction of vanadium pentoxide to vanadium (III) oxide, the reduction of vanadium (III) oxide to vanadium (II) oxide, the forming of vanadium nanoparticle from vanadium (II) oxide, or a combination thereof. The vanadium nanoparticle may bond with the boron released from the boric acid to form vanadium boride in aqueous solution.

[0026] In some embodiments, the method of forming vanadium boride may further include forming vanadium boride crystals. In some embodiments, forming vanadium boride crystals may include incubating the solution of the vanadium boride at about ambient temperature and pressure. In some embodiments, forming vanadium boride crystals may include incubating the solution of the vanadium boride at above ambient temperature, for example, about 40 °C to about 80 °C. In some embodiments, forming vanadium boride crystals may include incubating the solution of the vanadium boride at about 40°C to about 50°C, about 50°C to about 60°C, about 60°C to about 70°C, or about 70°C to about 80 °C. In some embodiments, forming the vanadium boride crystals may include incubating the solution of the vanadium boride at about ambient temperature and pressure for a period of time sufficient to form vanadium boride crystals. In some embodiments, forming the vanadium boride crystals may include incubating the solution of the vanadium boride at above ambient temperature, for example about 40 °C to about 80 °C, for a period of time sufficient to form vanadium boride crystals. The period of time can be about 1 hour, about 2 hours, about 4 hours, about 8 hours, about 12 hours, about 24 hours, about 36 hours, about 48 hours, or ranges between any two of these values (including endpoints). In some embodiments, forming the vanadium boride crystals may further include mixing or stirring the solution. The vanadium boride crystals may become visible on a surface of a reaction vessel after a period of time, such as about 2 hours from initiation of the reaction. The vanadium boride crystals may also continue to be formed on the surface of the reaction vessel for a period of time, such as up to about 48 hours after initiation of the reaction.

[0027] In some embodiments, the size and shape of the crystals being formed can be modulated by altering stirring speed, stirring time, the concentration of reactants, the concentration of the solvent, the type of solvent used, concentration of the reducing agent, the type of reducing agent used, the ethanol to water ratio in the reaction, the ratio of vanadium tetrachloride to vanadium bearing magnetite ore, the ratio of vanadium tetrachloride to vanadium bearing iron slag, the temperature of the reaction, the size of the reaction vessel, the shape of the reaction vessel and any combination thereof.

[0028] In some embodiments, the method of forming vanadium boride may further comprise coating the vanadium boride with an iron oxide. In some embodiments, the iron oxide may be iron oxide, iron (II) oxide, iron (III) oxide, iron (II, III) oxide, or any combination thereof. The iron oxide may be present in the vanadium-bearing ore and the vanadium-bearing iron slag, which forms a coating on the vanadium boride crystals. The iron oxide can also be additionally introduced to coat the vanadium boride. The coating may increase the vanadium boride 's resistance to corrosion. Figure 9 depicts vanadium boride crystals produced by the method described herein coated with iron oxide.

[0029] In some embodiments, the method of producing vanadium boride may be performed at about ambient temperature and pressure. In some embodiments, the method of producing vanadium boride may be performed at above ambient temperature, for example about 40 °C to about 80 °C. In some embodiments, the method of producing vanadium boride may be performed at about at about 40 °C to about 50 °C, about 50 °C to about 60 °C, about 60 °C to about 70 °C, or about 70 °C to about 80 °C. In some embodiments, the method may optionally be performed in a single reaction vessel. When the method is performed in a single reaction vessel, the vanadium boride may be formed in situ within a reaction mixture of the vanadium-bearing ore, vanadium-bearing iron slag, or both, the vanadium tetrachloride and the reducing agent. Figure 7 depicts the in situ formation of vanadium boride crystals from vanadium bearing iron slag performed in a single reaction vessel. Panel A shows the vanadium boride immediately after synthesis where hydrogen gas pushes the material in an upward direction. Panel B shows continued production of vanadium boride and hydrogen gas after 30 minutes. Panel C shows continued production of vanadium boride after 60 minutes. Panel D shows the appearance of a vanadium boride crystal on the reaction vessel wall after about 90 to 120 minutes. Panel E shows additional vanadium boride crystals forming on the reaction vessel wall and release of hydrogen gas. Panel F shows continued production appearance of vanadium boride crystals after 4 hours of synthesis. Panel G shows continued production appearance of vanadium boride crystals after 8 hours of synthesis. Panel H shows continued production appearance of vanadium boride crystals after 24 hours of synthesis. At this stage, the size of the vanadium boride crystals may increase significantly. Panel I shows the increasing size of the vanadium boride crystals after 36 hours of synthesis. Panel J shows the increasing size of the vanadium boride crystals after 40 hours of synthesis. Panel K shows the increasing size of the vanadium boride crystals after 42 hours of synthesis due to the presence of vanadium oxide (deep green in color). Panel L shows the increasing size of the vanadium boride crystals after 44 hours of synthesis. Panel M shows the increasing size of the vanadium boride crystals after 46 hours of synthesis. Panel N shows the vanadium boride crystals after completion of synthesis. As shown in Panel N, the vanadium boride crystals after completion of the synthesis are transparent and colorless.

[0030] During performance of the method, changes in the color of the reaction mixture may be observed either by eye or by using a machine, which can indicate the conversion of vanadium tetrachloride to vanadium pentoxide, vanadium pentoxide to vanadium (III) oxide, and vanadium (III) oxide to vanadium (II) oxide. The vanadium (II) oxide may be further reduced to vanadium nanoparticles, which can react with the boric acid to form vanadium boride in aqueous solution. Crystals of vanadium boride may then appear through incubating the solution under conditions as described in the disclosed embodiments. The color change may be from red (VC1₄), to yellow (V₂O₅), to blue (V₂O₃), and to green (VO). After the vanadium nanoparticles are formed, the color of the solution may change to white. Depending on the amount of vanadium-bearing ore or slag present, the final color may sometimes be grey due to the greyish residual materials from the ore or slag.

[0031] In an alternative embodiment, a method of producing vanadium boride may include reducing vanadium pentoxide contained in vanadium-bearing ore, vanadium-bearing iron slag, or both, to produce a vanadium nanoparticle; and forming vanadium boride from the vanadium nanoparticle.

[0032] Without wishing to be bound by theory, a series of reaction schemes are described below to form vanadium boride. The addition of sodium borohydride may result in the formation of vanadium (III) oxide according to reaction scheme (I):

V₂0₅ + 2VC1₄ + NaBH₄ + H₂0→ V2O3 + NaCl₄ + H3BO3 + H₂0 + C1₂(I)

[0033] The reduction of vanadium (III) oxide to vanadium (II) oxide may occur in situ. During reaction scheme I, the sodium borohydride may dissociate into sodium metaborate and hydrogen (H₂). The vanadium (III) oxide produced in reaction scheme (I) may be reduced to vanadium (II) oxide in the presence of the sodium metaborate and hydrogen (H₂) according to reaction scheme (II):

V₂0₃ + VC1₄ + NaB0₂ + 4H→ VO + NaCl + H₃BO₃ + H₂0 (II)

[0034] A vanadium nanoparticle may be formed in situ according to reaction scheme

(III):

2VO + HC1 + Cl₂ + 3NaB0₂ + 4H₂→ V + 3NaCl + H3BO3 + H₂0 (III)

[0035] With each successive reduction reaction occurring in reaction schemes I, II and III, boric acid may be formed, which can react with the vanadium nanoparticle to form vanadium boride according to reaction scheme (IV):

V + 2H3BO3 + 3H₂→ VB₂ + H₂0 (IV)

[0036] Figure 1 and Figure 4 depict X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) respectively, for vanadium boride produced from vanadium tetrachloride. In Figure 1, all vanadium borides are denoted as VB₂. In some embodiments, other vanadium borides may also be present including but not limited to V₃B₂, VB, V₅B₆, V₃B₄, V₂B₃, and VB₂. In some embodiments, the types of vanadium boride formed may be determined by the presence of vanadium bearing magnetite ore, vanadium bearing iron slag or combinations thereof. Figure 2 and Figure 5 depict X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) respectively, for vanadium boride produced from vanadium bearing magnetite ore. Figure 3 and Figure 6 depict X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) respectively, for vanadium boride produced from vanadium bearing iron slag respectively. In Figures 2 and 3, all vanadium borides are denoted as VB₂ or V₂B₃. In some embodiments, other vanadium borides may also be present including but not limited to V₃B₂, VB, V₅B₆, V₃B₄, V₂B₃, and VB₂. In some embodiments, the types of vanadium boride formed may be determined by the presence of vanadium bearing magnetite ore, vanadium bearing iron slag or combinations thereof. X-ray diffraction and Fourier transform infrared spectroscopy (FTIR) respectively, were performed using powdered vanadium boride crystals by standard methods well known to the skilled artisan.

[0037] Methods of producing metal boride (MB,/)

[0038] In an alternative embodiment, a method of producing a metal boride may include: reducing a metal oxide contained in metal bearing ore, metal bearing iron slag or both, to produce a metal nanoparticle; and forming a metal boride from the metal nanoparticle. In some embodiments, the metal bearing ore may be titaniferous magnetite ore, oxidized patronite, vanadinite, carnotite, or a combination thereof. In some embodiments, the metal oxide may be oxides of lithium, titanium, magnesium, manganese, aluminum, zinc, iron, or a combination thereof. [0039] The reducing of the metal oxide can be a catalytic reduction or non-catalytic reduction of the metal oxide to one or more intermediate metal oxides having a lower metal oxidation state than that of the metal oxide. For example, in the case of titanium, titanium dioxide Ti0₂ will be reduced to its intermediate metal oxides, dititanium trioxide Ti₂0₃ and titanium monooxide TiO, before forming titanium nanoparticle. Accordingly, the metal oxidation state or the oxidation state of titanium reduces from +4 in titanium dioxide, to +3 in dititanium trioxide, and to +2 in titanium monooxide. The series of reduction reactions may occur in situ within a single reaction vessel. In some embodiments, reducing the metal oxide may comprise contacting the metal oxide contained in metal bearing ore, metal bearing iron slag, or both, with a metal chloride. In some embodiments, the metal chloride corresponds to the metal boride being formed. For example, when the metal selected is lithium, the metal chloride is lithium chloride. The metal chloride may function as a catalytic reagent in the catalytic reduction process.

[0040] The metal bearing ore, the metal bearing iron slag, or both, may be in mixture or solution form before contacting with the metal chloride. Alternatively, the solvent may be added after the metal bearing ore, the metal bearing iron slag, or both, is contacted with the metal chloride. In some embodiments, reducing the metal oxide may further comprise contacting the metal oxide and the metal chloride with a solvent. To prepare the mixture or solution, the metal bearing ore, metal bearing iron slag or both, may be processed or milled into a powder followed by mixing with at least one solvent prior to being used in the methods described herein. In some embodiments, the solvent may be water, ethanol, isopropanol, methanol, or a combination thereof. In some embodiments, the solvent may be a mixture containing at least two of water, ethanol, isopropanol, and methanol. In some embodiments, the solvent may be a mixture of water and ethanol. In some embodiments, the water and ethanol may be present in the mixture in a ratio of about 1 to 2 by volume.

[0041] The reducing of the metal oxide may occur stepwise to form one or more intermediate metal oxides, before forming the metal nanoparticle. The reducing of the metal oxide to the one or more intermediate metal oxides may include contacting the metal oxide with at least one reducing agent after contacting the metal oxide with the metal chloride. The reducing agent can be any compound that is capable of releasing hydrogen (H₂) and providing the boron component in the resulting metal boride. In some embodiments, reducing the metal oxide may further comprise adding a borohydride compound, a borate compound and hydrogen (H₂), or both, after contacting the metal oxide with the metal chloride. In some embodiments, the borohydride compound may be sodium borohydride, lithium borohydride, sodium cyanoborohydride, potassium borohydride, lithium triethylborohydride, or combinations thereof. In some embodiments, the borate compound may be sodium metaborate, sodium borate, lithium metaborate, lithium borate, lithium tetraborate, or a combination thereof. Where the reducing agent is the borate compound and hydrogen (H₂), the borate compound and hydrogen (H₂) may be additionally introduced or may be formed in situ from an excess of the borohydride compound used in the reducing of the metal oxide to the one or more intermediate oxides. In some embodiments, reducing the metal oxide to the one or more intermediate metal oxides may further comprise contacting the metal oxide with hydrochloric acid, chlorine, or both. The hydrochloric acid and chlorine (Cl₂) may be additionally introduced or may be formed in situ from the reducing of the metal oxide to the one or more intermediate oxides. In some embodiments, reducing the metal oxide to the one or more intermediate metal oxides may further comprise contacting the metal oxide with sodium metaborate, hydrochloric acid, chlorine (Cl₂), and hydrogen (H₂).

[0042] The reducing of the intermediate metal oxide to metal nanoparticle may include contacting the intermediate metal oxide with at least one reducing agent. The reducing agent can be any compound that is capable of releasing hydrogen (H₂) and providing the boron component in the resulting metal boride. In some embodiments, reducing the intermediate metal oxide to the metal nanoparticle may further include contacting the intermediate metal oxide with a borohydride compound, a borate compound with hydrogen (H₂), or both. In some embodiments, the borohydride compound may be sodium borohydride, lithium borohydride, sodium cyanoborohydride, potassium borohydride, lithium triethylborohydride, or a combination thereof. In some embodiments, the borate compound may be sodium metaborate, sodium borate, lithium metaborate, lithium borate, lithium tetraborate, or a combination thereof. Where the reducing agent is the borate compound and hydrogen (H₂), the borate compound and hydrogen (H₂) may be additionally introduced or may be formed in situ from an excess of the borohydride compound used in the reducing of the metal oxide to the one or more intermediate metal oxides. In some embodiments, reducing the intermediate metal oxide to the metal nanoparticle may further include contacting the intermediate metal oxide with hydrochloric acid, chlorine (Cl₂), or both. The hydrochloric acid and chlorine (Cl₂) may be additionally introduced or may be formed in situ from the reducing of the metal oxide to the one or more intermediate metal oxides. In some embodiments, reducing the intermediate metal oxide to the metal nanoparticle may further include contacting the intermediate metal oxide with sodium metaborate, hydrochloric acid, chlorine (Cl₂), and hydrogen (H₂). [0043] In some embodiments, forming metal boride from the metal nanoparticle may include contacting the metal nanoparticle with boric acid. In some embodiments, forming the metal boride may further include contacting the metal nanoparticle with hydrogen (H₂). In some embodiments, forming the metal boride may include contacting the metal nanoparticle with boric acid and hydrogen (H₂). The boric acid and the hydrogen (H₂) may be additionally introduced, or may be formed in situ from the reduction of the metal oxide to the one or more intermediate metal oxides. The metal nanoparticle may bond with the boron released from the boric acid to form metal boride in aqueous solution.

[0044] In some embodiments, the method of forming metal boride may further include forming metal boride crystals. In some embodiments, forming metal boride crystals may include incubating a solution of the metal boride at about ambient temperature and pressure. In some embodiments, forming metal boride crystals may include incubating a solution of the metal boride at above ambient temperature, for example about 40 °C to 80 °C. In some embodiments, forming metal boride crystals may include incubating a solution of the metal boride at about 40 °C to about 50 °C, about 50 °C to about 60 °C, about 60 °C to about 70 °C, or about 70 °C to about 80 °C. In some embodiments, forming metal boride crystals may include incubating a solution of the metal boride at about ambient temperature and pressure for any period of time sufficient to obtain metal boride crystals, such as up to about 24 hours or more. In some embodiments, forming metal boride crystals may include incubating a solution of the metal boride at above ambient temperature, for example about 40 °C to about 80 °C, for any period of time sufficient to obtain metal boride crystals, such as up to about 24 hours or more. In some embodiments, forming metal boride crystals may include incubating a solution of the metal boride at ambient temperature and pressure for up to about 48 hours. In some embodiments, forming metal boride crystals may include incubating a solution of the metal boride at above ambient temperature, for example about 40 °C to 80 °C, for up to about 48 hours. In some embodiments, forming the metal boride crystals may further include mixing or stirring the solution. The metal boride crystals may become visible on a surface of the reaction vessel after a period of time, such as about 2 hours from initiation of the reaction. The metal boride crystals may also continue to be formed on the surface of the reaction vessel for a period of time, such as up to about 48 hours after initiation of the reaction. In some embodiments, the formation of the metal boride results in the formation of transparent colorless crystals.

[0045] In some embodiments, the method of forming metal boride may further include coating the metal boride with an iron oxide. The iron oxide can also be additionally introduced to coat the metal boride. The coating may increase the metal boride's resistance to corrosion. The iron oxide may be present in the titaniferous magnetite ore, oxidized patronite, vanadinite, carnotite, iron slag or combination thereof as a raw material in the methods described herein. The iron oxide can also be additionally introduced to coat the metal boride.

[0046] In some embodiments, the method of producing metal boride may be performed at about ambient temperature and pressure. In some embodiments, the method of producing metal boride may be performed at above ambient temperature, for example, about 40 °C to about 80 °C. In some embodiments, the method of producing metal boride may be performed at above ambient temperature, for example, about 40 °C to about 50 °C, about 50 °C to about 60 °C, about 60 °C to about 70 °C, or about 70 °C to about 80 °C. In some embodiments, the method of producing metal boride may be performed in a single reaction vessel. [0047] The costs of producing metal borides including, but are not limited to vanadium boride, using the methods described herein can be significantly lower than currently practiced commercial methods of production. For example, the cost of producing vanadium boride by the methods disclosed herein may be as much as one hundred times less expensive than currently practiced commercial manufacturing methods. [0048] The vanadium boride that is produced by the methods disclosed herein can have physical characteristics including but are not limited to hardness, electrical conductivity, a high melting point and the ability to break down in strong oxidizing or alkaline agents. In some embodiments, the hardness of the vanadium boride is determined by the hammer process. In some embodiments, vanadium boride produced from magnetite ore or iron slag is at least two times harder than vanadium boride produced from vanadium tetrachloride.

[0049] The vanadium boride produced by the methods disclosed herein can have multiple applications including but are not limited to automotive batteries with improved storage and discharge potentials, any application where electrical energy is used or can be used, and as a replacement for lithium and zinc electrodes in traditional fuel cells and batteries.

[0050] The vanadium boride produced by the methods disclosed herein can be suitable for use in vanadium boride air cells. The vanadium boride produced by the methods disclosed herein, when used in such cells, can have high energy storage capacity. The energy storage capacity can be equivalent to or greater than that of gasoline, lithium ion, or zinc air cell. [0051] The vanadium boride produced by the methods disclosed herein can be used as an anode in a battery. The vanadium boride produced by the methods disclosed herein can also be used as an anode in a rechargeable battery. Such rechargeable batteries can have a rapid recharge rate and greater energy storage capacity than lithium ion batteries. In non- rechargeable batteries, the vanadium boride produced by the methods disclosed herein can confer a superior charge storage density.

EXAMPLES

Example 1 - Preparation of titaniferous magnetite ore for use in the preparation of vanadium boride

[0052] 5 g of titaniferous magnetite ore was ground to a powder and mixed with 50 mL of deionized water to produce a 10% titaniferous magnetite ore solution.

Example 2 - Preparation of iron slag for use in the preparation of vanadium boride

[0053] 5 g of iron slag was ground to a powder and mixed with 50 mL of deionized water to produce a 10% iron slag ore solution.

Example 3 -Preparation of vanadium tetrachloride for use in the preparation of vanadium boride

[0054] Vanadium tetrachloride was freshly prepared from 1M vanadium pentoxide dissolved in concentrated hydrochloric acid (11.65M). The vanadium pentoxide was combined with the hydrochloric acid at a ratio of 1 : 10 by volume.

Example 4 - Preparation of vanadium tetrachloride for use in the preparation of vanadium boride

[0055] Vanadium tetrachloride was freshly prepared by combining 0.182 g of vanadium pentoxide with 4 mL of concentrated hydrochloric acid (11.65M), followed by mixing and a 10-minute incubation at ambient temperature and pressure.

Example 5 -In situ Preparation of vanadium boride from titaniferous magnetite ore [0056] 10 mL of titaniferous magnetite ore solution from Example 1 was mixed with

30 mL of a 2: 1 (v/v) ethanol and water mixture in a reaction vessel at ambient temperature and pressure. 1 mL of freshly prepared vanadium tetrachloride from Examples 3 or 4 was added to the titaniferous magnetite ore solution and ethanol and water mixture. Addition of the vanadium tetrachloride results in disassociation of vanadium pentoxide from the titaniferous magnetite ore. The combining of the titaniferous magnetite ore with vanadium tetrachloride was followed by the addition of 25 mL of 1M sodium borohydride to the reaction vessel to produce vanadium (III) oxide according to the following reaction scheme:

V₂0₅ + 2VC1₄ + NaBH₄ + H₂0→ V₂0₃ + NaCl₄ + H₃B0₃ + H₂0 + Cl₂

[0057] During the above reaction scheme, the sodium borohydride dissociated into sodium metaborate and hydrogen (H₂). The vanadium (III) oxide was reduced to vanadium (II) oxide in the presence of the sodium metaborate and hydrogen (H₂) according to the following reaction scheme:

V₂0₃ + VC1₄ + NaB0₂ + 4H₂→ VO + NaCl + H₃B0₃ + H₂0

[0058] A vanadium nanoparticle was formed from the vanadium (II) oxide in situ according to the following reaction scheme:

2VO + HC1 + Cl₂ + 3NaB0₂ + 4H₂→ V + 3NaCl + H₃B0₃ + H₂0 [0059] With each successive reduction reaction shown above, boric acid was formed which reacted with the vanadium nanoparticle to form vanadium boride according the following scheme:

V + 2H₃B0₃ + 3H₂→ VB₂ + H₂0

[0060] The reaction mixture was allowed to incubate at ambient temperature and pressure for about 48 hours resulting in the formation of vanadium boride crystals. The reaction mixture was stirred continuously during the incubation as well as during the process of adding the reactants.

[0061] As the vanadium boride crystals were formed in situ, they became coated by iron oxide that originates from the titaniferous magnetite ore solution. Example 6 - In situ Preparation of vanadium boride from iron slag [0062] 10 mL of iron slag solution from Example 1 was mixed with 30 mL of a 2: 1 (v/v) ethanol and water mixture in a reaction vessel at ambient temperature and pressure. 1 mL of freshly prepared vanadium tetrachloride from Examples 3 or 4 was added to the iron slag solution and ethanol and water mixture. Addition of the vanadium tetrachloride resulted in disassociation of vanadium pentoxide from the iron slag. The combining of the magnetite ore with vanadium tetrachloride was followed by the addition of 25 mL of 1M sodium borohydride to the reaction vessel to produce vanadium (III) oxide according to the following reaction scheme:

V₂0₅ + 2VC1₄ + NaBH₄ + H₂0→ V2O3 + NaCl₄ + H3BO3 + H₂0 + Cl₂

[0063] During the above reaction scheme, the sodium borohydride dissociated into sodium metaborate and hydrogen (H₂). The vanadium (III) oxide was reduced to vanadium (II) oxide in the presence of the sodium metaborate and hydrogen (H₂) according to the following reaction scheme:

V2O3 + VC1₄ + NaB0₂ + 4H→ VO + NaCl + H3BO3 + H₂0

[0064] A vanadium nanoparticle was formed from the vanadium (II) oxide in situ according to the following reaction scheme:

2VO + HC1 + Cl₂ + 3NaB0₂ + 4H₂→ V + 3NaCl + H3BO3 + H₂0

[0065] With each successive reduction reaction shown above, boric acid was formed which reacted with the vanadium nanoparticle to form vanadium boride according the following scheme:

V + 2H₃BO₃ + 3H₂→ VB₂ + H₂0

[0066] The reaction mixture was allowed to incubate at ambient temperature and pressure for about 48 hours resulting in the formation of vanadium boride crystals. The reaction mixture was stirred continuously during the incubation as well as during the process of adding the reactants.

[0067] As the vanadium boride crystals are formed in situ, they became coated by iron oxide that originates from the iron slag. Example 7 - Preparation of vanadium boride from magnetite ore

[0068] 10 mL of titaniferous magnetite ore solution from Example 1 is mixed with 30 mL of a 2: 1 (v/v) ethanol and water mixture in a reaction vessel at ambient temperature and pressure. 1 mL of freshly prepared vanadium tetrachloride from Examples 3 or 4 is added to the titaniferous magnetite ore solution and ethanol and water mixture. Addition of the vanadium tetrachloride results in disassociation of vanadium pentoxide from the magnetite ore. The combining of the ore with vanadium tetrachloride is followed by the addition of 25 mL of 1M sodium borohydride to the reaction vessel to produce vanadium (III) oxide.

[0069] 1M Sodium metaborate and an excess of hydrogen (¾) are then added to the reaction vessel at ambient temperature and pressure to yield vanadium (II) oxide. Fresh sodium metaborate is then added in excess to yield a vanadium nanoparticle.

[0070] 1M Boric acid is then added to the reaction vessel to produce vanadium boride. The reaction mixture is allowed to incubate at ambient temperature and pressure for about 48 hours resulting in the formation of vanadium boride crystals. The reaction mixture is stirred continuously during the incubation as well as during the process of adding the reactants.

Example 8 - Preparation of vanadium boride from iron slag

[0071] 10 mL of iron slag solution from Example 1 is mixed with 30 mL of a 2:1 (v/v) ethanol and water mixture in a reaction vessel at ambient temperature and pressure. 1 mL of freshly prepared vanadium tetrachloride from Examples 3 or 4 is added to the iron slag solution and ethanol and water mixture. Addition of the vanadium tetrachloride results in disassociation of vanadium pentoxide from the iron slag. The step of combining the slag with vanadium tetrachloride is followed by the addition of 25 mL of 1M sodium borohydride to the reaction vessel to produce vanadium (III) oxide. 1M Sodium metaborate and hydrogen (¾) are then added in excess to the reaction vessel at ambient temperature and pressure to yield vanadium (II) oxide. Fresh sodium metaborate is then added in excess to yield a vanadium nanoparticle.

[0072] 1M Boric acid is then added to the reaction vessel to produce vanadium boride. The reaction mixture is allowed to incubate at ambient temperature and pressure for about 48 hours resulting in the formation of vanadium boride crystals. The reaction mixture is stirred continuously during the incubation as well as during the process of adding the reactants.

Example 9 - Change in color as an indicator of progression in the preparation of vanadium boride from boride from titaniferous magnetite ore or iron slag

[0073] The addition of sodium borohydride to the reaction resulted in changes in the color of the reaction mixture of titaniferous magnetite ore or iron slag and vanadium tetrachloride. The color gradually changed from red (due to VC1₄), to yellow (due to V₂0₅), to blue (due to V₂0₃), and to green (due to VO). Following an incubation period at ambient temperature and pressure, a large amount of gas was released from the reaction mixture and the color of the reaction mixture changed from green to white. The gas produced is hydrogen, chlorine or a combination of both. Following the color change of the reaction mixture to white, the color changed again in rapid succession from white to black, to green and then to grey. The change in color of the reaction mixture to grey indicated completion of the reaction and formation of vanadium (III) oxide.

Incubation results in the formation of vanadium boride. At first, the solution appeared to be green/grey/steel grey in color depending on the concentration of reactants. As the vanadium boride crystals start to appear on the surface of the reaction vial after 2-3 hours of incubation. Once the crystals begin to appear, their size becomes larger and individual crystals cluster together to form a larger mass of crystals.

Example 10 - Preparation of vanadium boride microparticles and nanoparticles [0074] The particle size of vanadium boride crystals formed in any one of Examples 5 to 8 is affected by the time and speed of stirring of the vanadium boride during and after its formation. Micro- and nanoparticles of vanadium boride can be synthesized as a result of extended stirring times during and post synthesis.

Example 11 - Preparation of vanadium boride nanoparticles Vanadium boride is prepared by any one of Examples 5 to 8. The vanadium boride nanoparticles are produced by ball milling under argon environment in a tungsten carbide vessel using tungsten carbide bearings with a diameter of 10 mm. The vessel is then sealed and placed in a Retsch PM 100 ball-milling machine. The vanadium boride is milled at 600 rpm for 4 hours continuously. After milling, the temperature of the vessel is allowed to return ambient temperature and the vanadium boride nanoparticles are collected under an argon atmosphere.

Example 12 -Separation and purification of vanadium boride

[0075] Vanadium boride produced by any of Examples 5 to 8 can be separated from residual magnetite ore and iron slag, titanium oxide, iron oxide, aluminum oxide or other metal oxides that precipitate at the bottom of the reaction vessel in the process of producing vanadium boride from the magnetite ore or iron slag, by decantation and washing as vanadium boride is insoluble in water and ethanol.

[0076] After the formation of vanadium boride, such as in any one of Examples 5 to 8, impurities such as sodium chloride and boric acid is dissolved in the ethanol water mixture. Such impurities can be separated by decantation and washing.

[0077] Pure vanadium boride is obtained after a series of washing and decantation steps. The resulting vanadium boride may be coated with iron oxide that is also present in the reaction vessel. Example 13 - Preparation of a vanadium boride battery

[0078] Vanadium boride from magnetite ore or iron slag from any one of Examples 5 to 8 can be used as an anode in a rechargeable battery. The rechargeable battery is made up of two half-cells, an anode and an air cathode. The vanadium boride is mixed with carbon and potassium hydroxide to form the anode, which contains about 50% to about 80% vanadium boride and about 20% to about 50% carbon to achieve an optimum electrical discharge via multiple electron oxidation of vanadium boride. The electrolyte is an aqueous solution of potassium hydroxide (5M) as it is a suitable ionic conductor material. A membrane acting as a separator is also provided to minimize any non-electrochemical interaction between the anode and the air cathode. The vanadium boride undergoes an 11 electron per molecule oxidation which includes oxidation of the tetravalent transition metal ion, V (+4→ +5), and each of the two boron's 2xB (-2→ +3). The discharge potential of the high capacity battery is expected to be approximately 1.34 volts (V), whereas theoretical discharge potential is approximately 1.55 volts (V). The intrinsic storage capacity of the battery is expected to be about 1.55 volts (V) x 20,700 Ah/L = 32,000 Watt hours/liter (Wh/L). The anode had an open circuit potential of approximately 1.34 volts. At the anode, hydrogen is oxidized according to the reaction: VB₂ + 11 OH→ ½ V₂0₅ + B₂0₃ + ^U/₂ H₂0 + l ie- producing water and releasing two electrons. The electrons flow through an external circuit and return to the cathode, reducing oxygen in a reaction producing hydroxide ions: 0₂ + 2H₂0+4 e - = 11 OH, with the net reaction consuming one oxygen atom and two hydrogen atoms in the production of one water molecule. Electricity and heat are formed as by-products of this reaction.

Example 14 - Preparation of a vanadium boride battery

[0079] Vanadium boride derived from titaniferous magnetite ore or iron slag produced by any one of Examples 5 and 7 may be dissolved in 2 M potassium hydroxide solution to produce an anode, and the anode is added to the first half cell of a batteries. The battery may comprise two half-cells, which are in an electrochemical contact with each other through an electrolyte (potassium hydroxide). Potassium hydroxide can be used as an electrolyte in vanadium boride batteries because of its superior ionic conductivity. The first half-cell may comprise the vanadium boride anode and the second half-cell comprises a carbon air cathode. The anode, electrolyte, and carbon air cathodes and a separator, positioned to minimize any non-electrochemical interaction between the anode and the air cathode, may be sealed inside the battery cell. An electrical discharge from the anode occurs via multiple electron oxidation of vanadium boride. The battery may produce 1.34-volt open circuit discharge continuously.

Example 15 - Preparation of a vanadium boride battery [0080] Vanadium boride derived from iron slag as in Examples 6 or 8 may be dissolved in 2 M potassium hydroxide solution to produce an anode, and the anode is added to the first half cell of a batteries. The battery may comprise two half-cells, which are in an electrochemical contact with each other through an electrolyte (potassium hydroxide). Potassium hydroxide may be used as an electrolyte in vanadium boride batteries because of its superior ionic conductivity. The first half-cell may comprise the vanadium boride anode and the second half-cell may comprise a carbon air cathode. The anode, electrolyte, and carbon air cathodes and a separator, positioned to minimize any non-electrochemical interaction between the anode and the air cathode, are sealed inside the battery cell. An electrical discharge from the anode may occur via multiple electron oxidation of vanadium boride. The battery may produce 1.34-volt open circuit discharge continuously. Example 16 - Preparation of a vanadium boride-air button cell

[0081] Zinc Air button batteries with a 1 cm anode surface area can be used to produce a vanadium boride-air button cell. 0.1 g of ground vanadium boride from magnetite ore produced by Examples 5 or 7 may be mixed with activated carbon at a ratio of 1 : 1 in a porcelain crucible and a 5M potassium hydroxide solution may be added to produce a slurry that is used to replace the zinc anode in a conventional 1 cm diameter zinc-air button cell. The battery may discharge with a constant resistive load and exhibits higher potential. A 5M potassium hydroxide solution is used as the electrolyte. The loading of the anode material for each cell may be 10 mAh. To prepare the vanadium boride-air button cell, a zinc air button cell can be carefully opened, and the zinc anode and the carbon cathode material are removed. The vanadium boride slurry may then be added in the place of the zinc anode. A separator can then be placed over the vanadium boride anode. An activated carbon slurry can be prepared using 5M potassium hydroxide to produce an activated carbon slurry. The activated carbon slurry can replace the original carbon cathode in the lid of the of the button cell. The lid may then be placed on the separator above the anode making an airtight seal.

Example 17 - Preparation of a vanadium boride-air button cell

[0082] Zinc air button batteries with a 1 cm anode surface area can be used to produce a vanadium boride-air button cell. 0.1 g of ground vanadium boride from iron slag produced by Examples 6 or 8 may be mixed with activated carbon at a ratio of 1 : 1 in a porcelain crucible and a 5M potassium hydroxide solution may be added to produce a slurry that is used to replace the zinc anode in a conventional 1 cm diameter zinc-air button cell. The battery may discharge with a constant resistive load and exhibits higher potential. A 5M potassium hydroxide solution can be used as the electrolyte. The loading of the anode material for each cell may be 10 mAh. To prepare the vanadium boride-air button cell, a zinc air button cell can be opened, and the zinc anode and carbon cathode material are removed. The vanadium boride slurry is then added in the place of the zinc anode. A separator is then placed over the vanadium boride anode. An activated carbon slurry can be prepared using 5M potassium hydroxide to produce an activated carbon slurry. The activated carbon slurry then replaces the original carbon cathode in the lid of the button cell. The lid is then placed on the separator above the anode making an airtight seal. Example 18 - Preparation of a vanadium boride-air watch battery [0083] A 20.0 mm x 3.2 mm CR2032 watch battery with a lithium anode is used to prepare the battery. The cell is opened and the lithium anode is removed. The carbon cathode material is also removed. To produce the anode, 0.5 g of ground vanadium boride from magnetite ore produced by Example 5 or 7 is mixed with activated carbon powder at a 1 : 1 ratio in a porcelain crucible followed by adding a 5M potassium hydroxide solution to prepare a vanadium boride slurry. The vanadium boride slurry is then added in the place of the lithium anode. A separator is then placed over the vanadium boride anode. An activated carbon slurry is prepared using 5M potassium hydroxide to produce a carbon air cathode. The carbon air cathode is installed on the battery and the battery is tightly closed.

Example 19 - Preparation of a vanadium boride-air watch battery [0084] A 20.0 mm x 3.2 mm CR2032 watch battery with a lithium anode can be used to prepare the battery. The cell is opened and the lithium anode is removed. The carbon cathode material is also removed. To produce the anode, 0.5 g of ground vanadium boride from iron slag as produced by Examples 6 or 8 is mixed with activated carbon powder at a 1 : 1 ratio in a porcelain crucible followed by adding a 5M potassium hydroxide solution to prepare a vanadium boride slurry. The vanadium boride slurry is then added in the place of the lithium anode. A separator is then placed over the vanadium boride anode. An activated carbon slurry is prepared using 5M potassium hydroxide to produce a carbon air cathode. The carbon air cathode is installed on the battery and the battery is tightly closed.

Example 20 - Preparation of a vanadium boride-air coin battery [0085] A 5 cm coin battery with a lithium anode can be used to prepare the battery. 2 g of ground vanadium boride from magnetite ore as produced by Examples 5 or 7 is mixed with activated carbon powder (25%) in a porcelain crucible followed by the addition of 5M potassium hydroxide solution to prepare a vanadium boride anode slurry. The vanadium boride slurry is then added in the place of the lithium anode. A separator is then placed over the vanadium boride anode. An activated carbon slurry is prepared using 5M potassium hydroxide to produce a carbon air cathode. The carbon air cathode is installed on the battery and the battery is tightly closed.

Example 21 - Preparation of a vanadium boride-air coin battery [0086] A 5cm coin battery with a lithium anode can be used to prepare the battery. 2 g of ground vanadium boride from iron slag as produced by Examples 6 or 8 is mixed with activated carbon powder (25%) in a porcelain crucible followed by the addition of 5M potassium hydroxide solution to prepare a vanadium boride anode slurry. The vanadium boride slurry is then added in the place of the lithium anode. A separator is then placed over the vanadium boride anode. An activated carbon slurry is prepared using 5M potassium hydroxide to produce a carbon air cathode. The carbon air cathode is installed on the battery and the battery is tightly closed.

Example 22 - Comparison of vanadium boride batteries produced from various sources

[0087] Vanadium boride can be obtained from either vanadium chloride, magnetite ore as in Examples 5 and 7, or iron slag as in Examples 6 and 8. Vanadium boride batteries using vanadium boride from each source can be prepared as follows. Vanadium boride is dissolved in 2 M potassium hydroxide solution to produce a vanadium boride anode. The anode is then placed in the first half-cell a battery. The battery comprises two half-cells, which are in electrochemical contact with each other through an electrolyte (potassium hydroxide). Potassium hydroxide is used for its superior ionic conductivity. The first half- cell comprises the vanadium boride anode and the second half-cell comprises a carbon cathode.

[0088] The first half-cell, second half cell, and electrolyte are combined in a battery cell and a separator is placed between the first half-cell and the second half-cell. The battery cell is then sealed.

[0089] An electrical discharge from the anode (first half-cell) occurs via multiple electron oxidation of the vanadium boride. The battery may produce 1.34-volt open circuit discharge continuously.

[0090] Batteries using vanadium boride prepared from magnetite and iron slag may have a constant electrical discharge for a longer duration of time than batteries prepared with vanadium boride from vanadium chloride only. The increased discharge duration of batteries, prepared using vanadium boride may be due to the iron oxide coating, which makes the vanadium boride prepared from either magnetite ore of iron slag prepared from magnetite or iron slag. Example 23- Regeneration of vanadium boride after use

[0091] Regeneration of electrochemically irreversible alkaline vanadium boride from fuel cell discharge products can be done by treating with magnesium. Specifically, dried vanadate and borate products are combined with magnesium and ball milled for approximately 24 hours under an argon atmosphere at room temperature. Impurities including (e.g., magnesium oxide and residual reactants) are removed by leaching the milled powder with a 10% hydrochloric acid solution for approximately 1 hour. The solution is then decanted after leaching and the solid product is washed with deionized water and vacuum dried.

Example 24 -Regeneration of vanadium boride after use

[0092] Regeneration of electrochemically irreversible alkaline vanadium boride from fuel cell discharge products can be done by treating with heated hydrogen gas. Specifically, dried vanadate and borate products are combined with magnesium and ball milled for approximately 24 hour under an argon atmosphere at room temperature. Heated hydrogen gas is then passed over the vanadate and borate and reduces it back to a starting material for reinsertion into a refueled battery. The recharging process is performed at over 100°C to eliminate water formed from the hydrogen as steam.

[0093] The present disclosure is not to be limited in terms of the particular embodiments described in this application, which are intended as illustrations of various aspects. Many modifications and variations can be made without departing from its spirit and scope, as will be apparent to those skilled in the art. Functionally equivalent methods and apparatuses within the scope of the disclosure, in addition to those enumerated herein, will be apparent to those skilled in the art from the foregoing descriptions. Such modifications and variations are intended to fall within the scope of the appended claims. The present disclosure is to be limited only by the terms of the appended claims, along with the full scope of equivalents to which such claims are entitled. It is to be understood that this disclosure is not limited to particular methods, reagents, compounds, compositions or biological systems, which can, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting.

[0094] While various compositions, methods and devices are described in terms of "comprising" various components or steps (interpreted as meaning "including, but not limited to"), the compositions, methods, and devices can also "consist essentially of or "consist of the various components and steps, and such terminology should be interpreted as defining essentially closed-member groups.

[0095] With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity.

[0096] It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as "open" terms (e.g., the term "including" should be interpreted as "including but not limited to," the term "having" should be interpreted as "having at least," the term "includes" should be interpreted as "includes but is not limited to," etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases "at least one" and "one or more" to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles "a", "an", or "the" limits any particular claim containing such introduced claim recitation to embodiments containing only one such recitation, even when the same claim includes the introductory phrases "one or more" or "at least one" and indefinite articles such as "a", "an", or "the" (e.g., "a" and/or "an" and/or "the" should be interpreted to mean "at least one" or "one or more"); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should be interpreted to mean at least the recited number (e.g., the bare recitation of "two recitations," without other modifiers, means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to "at least one of A, B, and C, etc." is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., " a system having at least one of A, B, and C" would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances where a convention analogous to "at least one of A, B, or C, etc." is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., " a system having at least one of A, B, or C" would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase "A or B" will be understood to include the possibilities of "A" or "B" or "A and B." [0097] In addition, where features or aspects of the disclosure are described in terms of Markush groups, those skilled in the art will recognize that the disclosure is also thereby described in terms of any individual member or subgroup of members of the Markush group.

[0098] As will be understood by one skilled in the art, for any and all purposes, such as in terms of providing a written description, all ranges disclosed herein also encompass any and all possible subranges and combinations of subranges thereof. Any listed range can be easily recognized as sufficiently describing and enabling the same range being broken down into at least equal halves, thirds, quarters, fifths, tenths, etc. As a non-limiting example, each range discussed herein can be readily broken down into a lower third, middle third and upper third, etc. As will also be understood by one skilled in the art all language such as "up to," "at least," and the like include the number recited and refer to ranges that can be subsequently broken down into subranges as discussed above. Finally, as will be understood by one skilled in the art, a range includes each individual member. Thus, for example, a group having 1 -3 substituents refers to groups having 1 , 2, or 3 substituents. Similarly, a group having 1 -5 substituents refers to groups having 1 , 2, 3, 4, or 5 substituents, and so forth.

Claims

CLAIMS What is claimed:

1. A method of producing vanadium boride, the method comprising: reducing vanadium pentoxide contained in vanadium-bearing ore, vanadium- bearing iron slag or both, to produce vanadium (III) oxide; reducing the vanadium (III) oxide to vanadium (II) oxide; forming a vanadium nanoparticle from vanadium (II) oxide; and forming vanadium boride from the vanadium nanoparticle.

2. The method of claim 1, wherein the vanadium-bearing ore is titaniferous magnetite ore, oxidized patronite, vanadinite, carnotite, or a combination thereof.

3. The method of claim 1, wherein the vanadium-bearing ore comprises less than about 2% vanadium pentoxide by weight.

4. The method of claim 1, wherein the vanadium-bearing iron slag comprises less than about 25% vanadium pentoxide by weight.

5. The method of claim 1, wherein reducing the vanadium pentoxide comprises contacting the vanadium pentoxide contained in vanadium-bearing ore, vanadium-bearing iron slag, or both, with vanadium tetrachloride.

6. The method of claim 5, wherein reducing the vanadium pentoxide further comprises adding a borohydride compound, a borate compound and hydrogen (¾), or both, after contacting the vanadium pentoxide with vanadium tetrachloride.

7. The method of claim 6, wherein the borohydride compound is sodium borohydride, lithium borohydride, sodium cyanoborohydride, potassium borohydride and lithium triethylborohydride, or a combination thereof.

8. The method of claim 6, wherein the borate compound is sodium metaborate, sodium borate, lithium metaborate, lithium borate, lithium tetraborate, or a combination thereof.

9. The method of claim 5, wherein reducing the vanadium pentoxide further comprises contacting the vanadium pentoxide and the vanadium tetrachloride with a solvent.

10. The method of claim 9, wherein a solution of the vanadium-bearing ore, vanadium-bearing iron slag or both, in the solvent, and the vanadium tetrachloride, are contacted at a ratio of about 2 to 1 to about 20 to 1 by volume

11. The method of claim 10, wherein the solvent is water, ethanol, isopropanol, methanol, or a combination thereof.

12. The method of claim 10, wherein the solvent is a mixture of water and ethanol.

13. The method of claim 12, wherein the water and ethanol are present in a ratio of water to ethanol of about 1 to 2 by volume.

14. The method of claim 1, wherein reducing the vanadium (III) oxide to vanadium (II) oxide comprises contacting the vanadium (III) oxide with a borohydride compound, a borate compound and hydrogen (H₂), or both.

15. The method of claim 14, wherein the borohydride compound is sodium borohydride, lithium borohydride, sodium cyanoborohydride, potassium borohydride and lithium triethylborohydride, or a combination thereof.

16. The method of claim 14, wherein the borate compound is sodium metaborate, sodium borate, lithium metaborate, lithium borate, lithium tetraborate, or a combination thereof.

17. The method of claim 14, wherein reducing the vanadium (III) oxide to vanadium (II) oxide further comprises contacting the vanadium (III) oxide with hydrochloric acid, chlorine (Cl₂), or both.

18. The method of claim 1 , wherein reducing the vanadium (III) oxide to vanadium (II) oxide comprises contacting the vanadium (III) oxide with sodium metaborate, hydrochloric acid, chlorine (Cl₂), and hydrogen (H₂).

19. The method of claim 1, wherein forming the vanadium nanoparticle comprises contacting the vanadium (II) oxide with a borohydride compound, a borate compound and hydrogen (H₂), or both.

20. The method of claim 19, wherein the borohydride compound is sodium borohydride, lithium borohydride, sodium cyanoborohydride, potassium borohydride and lithium triethylborohydride, or a combination thereof.

21. The method of claim 19, wherein the borate compound is sodium metaborate, sodium borate, lithium metaborate, lithium borate, lithium tetraborate, or a combination thereof.

22. The method of claim 19, wherein forming the vanadium nanoparticle further comprises contacting the vanadium (II) oxide with hydrochloric acid, chlorine (Cl₂), or both.

23. The method of claim 1, wherein forming the vanadium nanoparticle comprises contacting the vanadium (II) oxide with sodium metaborate, hydrochloric acid, chlorine (Cl₂), and hydrogen (H₂) .

24. The method of claim 1 , wherein forming the vanadium boride from the vanadium nanoparticle comprises contacting the vanadium nanoparticle with boric acid.

25. The method of claim 24, wherein forming the vanadium boride from the vanadium nanoparticle further comprises contacting the vanadium nanoparticle with hydrogen (H₂).

26. The method of claim 1, wherein forming the vanadium boride from the vanadium nanoparticle comprises contacting the vanadium boride nanoparticle with boric acid and hydrogen (H₂).

27. The method of claim 1, further comprising forming vanadium boride crystals.

28. The method of claim 27, wherein forming the vanadium boride crystals comprises incubating a solution of the vanadium boride at ambient temperature and pressure.

29. The method of claim 27, wherein forming the vanadium boride crystals comprises incubating a solution of the vanadium boride at ambient temperature and pressure for up to about 24 hours to about 48 hours.

30. The method of claim 28, wherein forming the vanadium boride crystals further comprises stirring the solution.

31. The method of claim 1 , further comprising coating the vanadium boride with an iron oxide.

32. The method of claim 1, wherein the method is performed at ambient temperature and pressure.

33. The method of claim 1, wherein the method is performed in a single reaction vessel.

34. A method of producing vanadium boride, the method comprising: reducing vanadium (V) pentoxide contained in vanadium-bearing ore, vanadium-bearing iron slag, or both, to produce a vanadium nanoparticle; and forming vanadium boride from the vanadium nanoparticle.

35. The method of claim 34, wherein the vanadium-bearing ore is titaniferous magnetite ore, oxidized patronite, vanadinite, carnotite, or a combination thereof.

36. The method of claim 34, wherein the vanadium-bearing ore comprises less than about 2% vanadium pentoxide by weight.

37. The method of claim 34, wherein the vanadium-bearing iron slag comprises less than about 25% vanadium pentoxide by weight.

38. The method of claim34, wherein reducing the vanadium pentoxide comprises contacting the vanadium pentoxide contained in vanadium-bearing ore, vanadium-bearing iron slag, or both, with vanadium tetrachloride.

39. The method of claim 38, wherein reducing the vanadium pentoxide further comprises adding a borohydride compound, a borate compound and hydrogen (H₂), or both, after contacting the vanadium pentoxide with the vanadium tetrachloride to form vanadium (III) oxide.

40. The method of claim 39, wherein the borohydride compound is sodium borohydride, lithium borohydride, sodium cyanoborohydride, potassium borohydride, lithium triethylborohydride, or a combination thereof.

41. The method of claim 39, wherein the borate compound is sodium metaborate, sodium borate, lithium metaborate, lithium borate, lithium tetraborate, or a combination thereof.

42. The method of claim 38, wherein reducing the vanadium pentoxide further comprises contacting the vanadium pentoxide and vanadium tetrachloride with a solvent.

43. The method of claim 42, wherein a solution of the vanadium-bearing ore, vanadium-bearing iron slag, or both, in the solvent, and the vanadium tetrachloride, are contacted at a ratio of about 2 to 1 to about 20 to 1 by volume.

44. The method of claim 43, wherein the solvent is water, ethanol, isopropanol, methanol, or a combination thereof.

45. The method of claim 43, wherein the solvent is a mixture of water and ethanol.

46. The method of claim 45, wherein the water and ethanol are present in a ratio of about 1 to 2 by volume.

47. The method of claim 40, wherein reducing vanadium pentoxide further comprises contacting the vanadium (III) oxide with a borohydride compound, a borate compound and hydrogen (H₂), or both, to form vanadium (II) oxide.

48. The method of claim 47, wherein the borohydride compound is sodium borohydride, lithium borohydride, sodium cyanoborohydride, potassium borohydride, lithium triethylborohydride, or a combination thereof.

49. The method of claim 47, wherein the borate compound is sodium metaborate, sodium borate, lithium metaborate, lithium borate, lithium tetraborate, or a combination thereof.

50. The method of claim 47, wherein reducing vanadium pentoxide further comprises contacting the vanadium (III) oxide with hydrochloric acid, chlorine (Cl₂), or both.

51. The method of claim 40, wherein reducing vanadium pentoxide further comprises contacting the vanadium (III) oxide with sodium metaborate, hydrochloric acid, chlorine, and hydrogen (H₂) to form vanadium (II) oxide.

52. The method of claim 47, wherein reducing vanadium pentoxide further comprises contacting the vanadium (II) oxide with a borohydride compound, a borate compound and hydrogen (¾), or both, to form the vanadium nanoparticle.

53. The method of claim 52, wherein the borohydride compound is sodium borohydride, lithium borohydride, sodium cyanoborohydride, potassium borohydride, lithium triethylborohydride, or a combination thereof.

54. The method of claim 52, wherein the borate compound is sodium metaborate, sodium borate, lithium metaborate, lithium borate, lithium tetraborate, or a combination thereof.

55. The method of claim 52, wherein reducing vanadium pentoxide further comprises contacting the vanadium (II) oxide with hydrochloric acid, chlorine, or both.

56. The method of claim 47, wherein reducing vanadium pentoxide further comprises contacting the vanadium (II) oxide with sodium metaborate, hydrochloric acid, chlorine, and hydrogen (¾) to form the vanadium nanoparticle.

57. The method of claim 34, wherein forming the vanadium boride comprises contacting the vanadium nanoparticle with boric acid.

58. The method of claim 57, wherein forming the vanadium boride further comprises contacting the vanadium nanoparticle with hydrogen (¾).

59. The method of claim 34, wherein forming the vanadium boride comprises contacting the vanadium boride nanoparticle with boric acid and hydrogen (¾).

60. The method of claim 34, further comprising forming vanadium boride crystals.

61. The method of claim 54, wherein forming the vanadium boride crystals comprises incubating a solution of the vanadium boride at ambient temperature and pressure.

62. The method of claim 54, wherein forming the vanadium boride crystals comprises incubating a solution of the vanadium boride at ambient temperature and pressure for up to about 24 hours to about 48 hours.

63. The method of claim 61, wherein forming the vanadium boride crystals further comprises stirring the solution.

64. The method of claim 34, further comprising coating the vanadium boride with an iron oxide.

65. The method of claim 34, wherein the method is performed at ambient temperature and pressure.

66. The method of claim 34, wherein the method is performed in a single reaction vessel.

67. A method of producing a metal boride, the method comprising: reducing a metal oxide contained in a metal bearing ore, metal bearing iron slag or both, to produce a metal nanoparticle; and forming a metal boride from the metal nanoparticle.

68. The method of claim 67, wherein the metal bearing ore is titaniferous magnetite ore, oxidized patronite, vanadinite, carnotite, or a combination thereof.

69. The method of claim 67, wherein the metal oxide is an oxide of lithium, titanium, magnesium, manganese, aluminum, zinc, iron, or a combination thereof.

70. The method of claim 67, wherein reducing the metal oxide comprises contacting the metal oxide contained in the metal bearing ore, metal bearing iron slag or both, with a metal chloride.

71. The method of claim 70, wherein the metal chloride corresponds to the metal boride being formed.

72. The method of claim 67, wherein reducing the metal oxide further comprises adding a borohydride compound, a borate compound and hydrogen (¾), or both, after contacting the metal oxide with the metal chloride to form one or more intermediate metal oxides having a metal oxidation state lower than that of the metal oxide.

73. The method of claim 72, wherein the borohydride compound is sodium borohydride, lithium borohydride, sodium cyanoborohydride, potassium borohydride, lithium triethylborohydride, or a combination thereof.

74. The method of claim 72, wherein the borate compound is sodium metaborate, sodium borate, lithium metaborate, lithium borate, lithium tetraborate, or a combination thereof.

75. The method of claim 70, wherein reducing the metal oxide further comprises contacting the metal oxide and the metal chloride with a solvent.

76. The method of claim 75, wherein the solvent is water, ethanol, isopropanol, methanol or a combination thereof.

77. The method of claim 75, wherein the solvent is a mixture of water and ethanol.

78. The method of claim 77, wherein the water and ethanol are present in a ratio of about 1 to 2by volume.

79. The method of claim 72, wherein reducing the metal oxide further comprises contacting the one or more intermediate metal oxides with a borohydride compound, borate compound and hydrogen, or both, to form the metal nanoparticle.

80. The method of claim 79, wherein the borohydride compound is sodium borohydride, lithium borohydride, sodium cyanoborohydride, potassium borohydride, lithium triethylborohydride, or a combination thereof

81. The method of claim 79, wherein the borate compound is sodium metaborate, sodium borate, lithium metaborate, lithium borate, lithium tetraborate, or a combination thereof.

82. The method of claim 79, wherein reducing the metal oxide further comprises contacting the one or more intermediate metal oxides with hydrochloric acid, chlorine (Cl₂), or both.

83. The method of claim 72, wherein reducing the metal oxide further comprises contacting the one or more intermediate metal oxides with sodium metaborate, hydrochloric acid, chlorine (Cl₂), and hydrogen (H₂) to form the metal nanoparticle.

84. The method of claim 67, wherein forming the metal boride comprises contacting the metal nanoparticle with boric acid.

85. The method of claim 84, wherein forming the metal boride further comprises contacting the metal nanoparticle with hydrogen (¾).

86. The method of claim 67, wherein forming the metal boride comprises contacting the metal nanoparticle with boric acid and hydrogen (¾).

87. The method of claim 67, further comprising forming metal boride crystals.

88. The method of claim 87, wherein forming the metal boride crystals comprises incubating a solution of the metal boride at ambient temperature and pressure.

89. The method of claim 87, wherein forming the metal boride crystals comprises incubating a solution of the metal boride at ambient temperature and pressure for up to about 24 hours to about 48 hours.

90. The method of claim 88, wherein forming the metal boride crystals further comprises stirring the solution.

91. The method of claim 67, further comprising coating the metal boride with an iron oxide.

92. The method of claim 67, wherein the method is performed at ambient temperature and pressure.

93. The method of claim 67, wherein the method is performed in a single reaction vessel.