Method for preparing MXene from titanium ore slag resource utilization

Abstract

This invention discloses a method for preparing MXene through the resource utilization of titanium slag. The method includes: heating titanium slag, hydrocarbons and / or nitrogen gas, and hydrogen halide gas and / or elemental halogen gas to a reaction temperature, followed by cooling to obtain a solid product containing MXene material. This invention uses low-value titanium slag as raw material and utilizes the titanium element therein to synthesize high-value-added MXene material. This invention explores the application value of titanium slag and provides a high-value-added industrial application direction for the resource utilization of titanium slag.

Description

Technical Field

[0001] This invention belongs to the field of environmental resource utilization, and in particular relates to a method for preparing MXene by utilizing titanium slag resources. Background Technology

[0002] my country is rich in vanadium-titanium magnetite, while titanium slag is an industrial solid waste produced during pig iron smelting. The main chemical component of titanium slag is TiO2, which generally exceeds 10%, and in some cases even exceeds 20%. Due to its high titanium content, titanium slag cannot be directly used to produce slag silicate cement; furthermore, its titanium grade is not high enough to make it suitable as a raw material for the titanium industry. The large amount of titanium slag not being utilized properly not only wastes resources and occupies huge areas of storage sites but also pollutes the environment. Currently, the resource utilization of titanium slag, titanium-vanadium slag, and vanadium slag is mainly in construction projects. However, the application value or industrial added value of these slags as aggregates in ordinary concrete is extremely low, and their resource and functional attributes are not fully utilized. Summary of the Invention

[0003] The purpose of this invention is to address the problem of extremely low application value or industrial added value of titanium slag resource utilization. It provides a method for preparing MXene from titanium slag resource utilization, using low-value titanium slag as raw material and utilizing the titanium element to synthesize high-value-added MXene materials. This invention explores the application value of titanium slag, providing a high-value-added application direction for the resource utilization of titanium slag.

[0004] The first aspect of this invention provides a method for preparing MXene by utilizing titanium slag resources. The method includes: heating titanium slag, hydrocarbons and / or nitrogen, and hydrogen halide gas and / or halogen gas to a reaction temperature, and cooling to obtain a solid product, wherein the solid product contains MXene material.

[0005] In some embodiments, the hydrocarbon is one or more of an alkane, olefin, or alkyne.

[0006] In some embodiments, the hydrocarbon is in a gaseous state.

[0007] In some embodiments, the hydrogen halide gas is selected from HCl, HBr, or HI; the halogen gas is selected from Cl2, Br2, or I2.

[0008] In some embodiments, the raw materials used in the above method contain carbon materials.

[0009] In some embodiments, the alkane is selected from one or more of methane, ethane, propane, and butane.

[0010] In some embodiments, the olefin is selected from one or more of ethylene, propylene, and butene.

[0011] In some embodiments, the alkyne is selected from acetylene and methylacetylene.

[0012] In some embodiments, the titanium oxide content in the slag is ≥10% by mass; more preferably, ≥20%.

[0013] In some embodiments, the titanium slag contains vanadium oxide;

[0014] In some embodiments, the titanium slag is selected from one or more of the following: titanium-containing blast furnace slag produced by blast furnace smelting of vanadium-titanium magnetite, molten titanium slag produced by pre-reduction electric furnace smelting, or titanium-rich slag obtained by pre-reduction grinding and beneficiation.

[0015] In some embodiments, the above method includes more specific steps including: heating titanium slag powder in a high-temperature furnace to the reaction temperature, introducing gaseous hydrocarbon and hydrogen halide gases and holding it at the temperature for a predetermined time, and then cooling it to room temperature to obtain a solid product.

[0016] In some embodiments, the above method includes more specific steps including: placing titanium slag powder and carbon powder into a high-temperature furnace and heating to the reaction temperature, then introducing chlorine gas and holding at the temperature for a predetermined time, and finally cooling to room temperature to obtain a solid product.

[0017] In some embodiments, the method further includes a purification step to remove impurities from the solid product.

[0018] In some embodiments, the purification steps described above include: washing the solid product obtained after the reaction in an acid solution and then adding it back in; dispersing the product in a non-aqueous solvent after the reaction; and then separating it by precipitation or centrifugation.

[0019] In some embodiments, the acid solution is selected from one or more of hydrochloric acid, sulfuric acid, hydrofluoric acid, phosphoric acid, or nitric acid.

[0020] In some embodiments, the non-aqueous solvent is selected from one or more of propylene carbonate (PC), dimethyl sulfoxide (DMSO), N-methylpyrrolidone (NMP), acetonitrile (ACN), N,N-dimethylformamide (DMF), N-methylformamide (NMF), and isopropanol (IPA).

[0021] In some embodiments, the reaction temperature is between 500°C and 1500°C, preferably between 650°C and 900°C; and / or, the holding time at the reaction temperature is between 1 min and 24 h; preferably between 30 min and 4 h.

[0022] In some embodiments, the chemical formula of the above-mentioned MXene material is M2XT. xOr M2X, where M represents titanium and / or vanadium; X represents carbon and / or nitrogen; T represents a functional group, wherein T includes at least one of Cl, Br, and I, and 0 < x ≤ 2.

[0023] A second aspect of the present invention provides an application of the MXene material obtained by the above method in energy, catalysis, adsorption separation, sensing and detection, electromagnetic shielding, biomedicine, gas storage, microwave absorbing materials, corrosion-resistant materials, or superconducting materials.

[0024] A third aspect of the present invention provides the use of slag as a raw material for preparing MXene materials, wherein the slag contains titanium oxide and / or vanadium oxide; preferably, the mass content of titanium oxide in the slag is ≥10%; more preferably, ≥20%; and even more preferably, ≥50%; or, the slag is selected from one or more of the following: titanium-containing blast furnace slag produced by blast furnace smelting of vanadium-titanium magnetite, molten titanium slag produced by pre-reduction electric furnace smelting, or titanium-rich slag obtained by pre-reduction grinding and beneficiation.

[0025] This invention provides a method for preparing MXene from titanium slag using a gas-phase method. On one hand, this offers a new direction for the resource utilization of industrial waste titanium slag. On the other hand, it reduces the synthesis cost of MXene materials by utilizing transition metal elements such as titanium and vanadium in the titanium slag, thereby lowering the raw material cost for MXene synthesis. The preparation process uses gas-phase raw materials (gaseous halide hydrides or elements) to directly synthesize MXene materials, avoiding the synthesis of the MAX phase and the liquid-phase etching step using the MAX phase as a precursor, thus simplifying the preparation process. Attached Figure Description

[0026] Figure 1 The MXene Ti2CCl prepared after purification in Example 1 of this invention x XRD patterns.

[0027] Figure 2 MXene Ti2CCl in Embodiment 1 of the present invention x TEM image (a) and HRTEM image (b).

[0028] Figure 3 MXene Ti2CCl in Embodiment 1 of the present invention x The SEM image (a) and the corresponding EDS image of the region are shown, where (b-d) correspond to the Ti, C and Cl elements, respectively.

[0029] Figure 4 MXene Ti in Embodiment 2 of the present invention a V b CCl x XRD patterns.

[0030] Figure 5 MXene Ti in Embodiment 2 of the present invention a V b CCl x The SEM image (a) and the corresponding EDS image of the region are shown, where (b-e) correspond to the elements Ti, V, C and Cl, respectively.

[0031] Figure 6 MXene Ti2NCl in Embodiment 3 of the present invention x XRD patterns.

[0032] Figure 7 MXene Ti2CI in Embodiment 4 of the present invention x XRD patterns.

[0033] Figure 8 MXene Ti2CCl in Embodiment 5 of the present invention x XRD patterns. Detailed Implementation

[0034] The technical solution of the present invention is illustrated below through specific embodiments. It should be understood that the one or more steps mentioned in the present invention do not preclude the existence of other methods and steps before or after the combined steps, or that other methods and steps may be inserted between these explicitly mentioned steps. It should also be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Unless otherwise stated, the numbering of each method step is only for the purpose of identifying each method step, and not for limiting the order of each method or limiting the scope of the present invention. Changes or adjustments to their relative relationships, without substantial changes to the technical content, can also be considered as within the scope of the present invention.

[0035] The raw materials and instruments used in the examples are not subject to any specific restrictions on their source; they can be purchased from the market or prepared according to conventional methods known to those skilled in the art.

[0036] MXene is a two-dimensional transition metal carbide, nitride, or carbonitride. The chemical formula for MXene can be represented as M... n+1 X n T x Where M represents a pre-transition metal element (Sc, Ti, V, Cr, Zr, Nb, Mo, etc.), X represents C and / or N, T represents a surface end group (-O, -OH, -F, etc.), 0 < x ≤ 2, T xThis indicates the presence of functional groups on the surface of MXene. Due to the diversity of composition and structure of the MAX phase, MXene materials derived from it have become the largest family of two-dimensional materials, with over 100 theoretically predicted and more than 40 synthesized to date. The mainstream route for preparing MXene, from the precursor MAX phase to obtaining two-dimensional MXene, generally involves two steps: etching away the atom layer from the MAX phase and then performing intercalation and exfoliation on multi-layered MXene. Most etching methods rely on ferrite (F). - The presence of substances such as HF acid, fluorine-containing salts (LiF, NaF, KF, etc.) and acids. Because the preparation of MXene requires MAX phase precursors as raw materials, and MAX phase precursors need to be sintered at high temperatures; the MAX phase liquid-phase etching process inevitably requires multiple steps of cleaning, filtration, and drying, resulting in extremely high MXene preparation costs, which seriously hinders the industrial application of MXene materials.

[0037] The technical features of the present invention are illustrated below through specific embodiments:

[0038] The present invention uses two titanium slags with different titanium contents. One type of titanium slag has the following main chemical composition by mass: TiO2 21.5%, CaO 26.4%, SiO2 24.2%, Al2O3 13.3%, MgO 8.7%, Fe2O3 2.5%, SO3 1.1%, and impurities (K2O, P2O5, Na2O, etc.) with a mass content of <1%. The other type of titanium slag contains vanadium oxides and is called titanium vanadium slag. Its main chemical composition by mass includes: TiO2 57.7%, V2O5 3.0%, CaO 8.3%, SiO2 9.6%, Al2O3 4.3%, MgO 5.9%, Fe2O3 8.3%, MnO 1.3%, and impurities (SO3, K2O, P2O5, Na2O, etc.) with a mass content of <1%.

[0039] This invention also includes refining vanadium slag to obtain vanadium slag powder, increasing the contact area with gaseous raw materials and improving reaction efficiency; however, the refining step is not mandatory. Refining can be achieved through methods such as crushing, grinding, and ball milling. In this invention, the vanadium slag is ball-milled for a predetermined time and then sieved to obtain vanadium slag powder. Specifically, the ball milling step includes: adding vanadium slag to a planetary ball mill at a ball-to-material ratio of (1-10):1, ball milling for 1-24 hours, and then passing the powder through a 50-400 mesh sieve to obtain titanium slag or powder.

[0040] Example 1

[0041] This embodiment provides a method for preparing MXeneTi2CCl using vanadium slag, methane (CH4), and hydrogen chloride gas (HCl) as raw materials. x The method, including the following steps:

[0042] 1) Place 10g of vanadium slag powder (sieved through 200 mesh) in a ceramic boat, put it into a tube furnace, and introduce argon gas into the tube furnace. Set the heating program of the tube furnace to increase the temperature to the reaction temperature of 750 degrees at a rate of 20℃ / min. Argon gas is used as a protective gas during the heating process.

[0043] 2) When the temperature reaches the preset temperature of 750 degrees Celsius, hydrogen chloride and methane gases are introduced into the tubular furnace, making the volume fraction of hydrogen chloride gas 10% and the volume fraction of methane gas 5%. The furnace is held at this temperature for 1 hour to carry out the gas-phase growth reaction. During this process, TiO2 in the vanadium slag reacts with HCl to form TiCl4, which is also gaseous at this reaction temperature. The gaseous TiCl4 reacts with gaseous methane at high temperature to synthesize solid MXene Ti2CCl. x , deposited in the tubular furnace;

[0044] 3) After the set holding time, change the gas in the tube furnace back to argon, open the lid and air cool to room temperature, then collect the solid products in the tube furnace.

[0045] 4) Purification steps: The solid product was dispersed in 20wt% hydrofluoric acid and stirred for 6h. After washing and drying with deionized water, the product was added to non-aqueous dispersion propylene carbonate (PC) and ultrasonically dispersed. The precipitate was removed by centrifugation, which effectively removed impurities such as TiC, CaO, Fe2O3, Al2O3, SiO2, K2O, and Na2O.

[0046] SiO2 reacts with hydrofluoric acid to form fluorosilicic acid; metal oxides such as calcium, magnesium, and iron react with hydrofluoric acid to form metal fluoride precipitates; fluorosilicic acid is soluble in solution and reacts with metal fluorides, further removing impurities such as calcium, magnesium, and iron fluorides. Taking CaO as an example, the purification steps involve the reactions: CaO + 2HF = CaF2 + H2O, SiO2 + 6HF = H2SiF6 + 2H2O, and CaF2 + H2SiF6 = CaSiF6 + HF.

[0047] X-ray diffraction (XRD) analysis was performed on the purified solid product, and the results are as follows: Figure 1 As shown, the XRD pattern is similar to that of Ti2CCl2 MXene obtained by Lewis acid molten salt etching of the Ti2AlC MAX phase, with a strong diffraction peak appearing at around 6.9 degrees, corresponding to Ti2CCl x The diffraction peaks of the MXene(002) crystal plane indicate that Ti2CCl was successfully prepared by growth using titanium slag, methane, and hydrogen chloride gas. x MXene.

[0048] The prepared MXene Ti2CT xAfter liquid-phase exfoliation, the sample was characterized by transmission electron microscopy (TEM), and the results are as follows: Figure 2 As shown in Figure a, it exhibits a two-dimensional nanosheet structure. Figure 2 b is a high-resolution transmission electron microscope (HRTEM) image and its output via FFT. Figure 2 The diffraction spots obtained (see illustration b) show that the product has a hexagonal crystal structure, consistent with the reported structure of MXene and the XRD analysis results. Energy dispersive spectroscopy (EDS) analysis reveals that this MXene Ti2CT... x Distribution of Ti, C and Cl elements in the middle (corresponding to Figure 3 (b), (c), and (d) indicate that the target product obtained is an MXene material Ti2CCl containing Cl functional groups. x .

[0049] Example 2

[0050] This embodiment provides a method for preparing MXene using vanadium-titanium ore slag, methane (CH4), and hydrogen chloride gas (HCl) as raw materials. Similar to Embodiment 1, the difference lies in replacing titanium ore slag powder with titanium-vanadium ore slag powder. In step 2, TiO2 and V2O5 in the titanium-vanadium ore slag react with HCl to generate TiCl4 and VCl5, respectively. Both are gaseous at this reaction temperature. The gaseous TiCl4 and VCl5 react with gaseous methane at high temperature to synthesize a solid MXene material, which is then deposited in a tube furnace. The M metal site in this MXene material is titanium and / or vanadium, represented by the chemical formula Ti. a V b CCl x In (a+b=2, 0<x≤2).

[0051] The collected solid products were analyzed by X-ray diffraction (XRD), and the results are as follows: Figure 4 As shown, the XRD pattern shows a strong diffraction peak at around 8.1 degrees, which corresponds to the diffraction peak of the MXene(002) crystal plane. This indicates that MXene was successfully prepared by growth using titanium vanadium slag, methane, and hydrogen chloride gas.

[0052] EDS analysis of the purified solid product revealed the elemental distributions of Ti, V, C, and Cl in the two-dimensional nanosheets (corresponding to...). Figure 5 The values ​​b, c, d, and e in the figure indicate that the target product obtained is an MXene material Ti containing Cl functional groups. a V b CCl x .

[0053] Example 3

[0054] This embodiment provides a method for preparing nitrogen-containing MXene Ti2NT using titanium slag, nitrogen, and hydrogen chloride gas as raw materials.x (or written as: Ti2NCl) x The method (0 < x ≤ 2) is similar to that in Example 1, except that methane gas is replaced with nitrogen gas (N2), the volume fraction of nitrogen gas is 20%, the volume fraction of hydrogen chloride gas is 10%, the reaction temperature is adjusted to 650°C, and the temperature is maintained for 30 min.

[0055] X-ray diffraction (XRD) analysis was performed on the purified solid product, and the results are as follows: Figure 6 As shown, the XRD pattern is similar to that of Ti2NCl2 MXene obtained by Lewis acid molten salt etching of the Ti2AlN MAX phase, with a strong diffraction peak appearing at around 5.9 degrees, corresponding to Ti2NCl x The diffraction peaks of the MXene(002) crystal plane indicate that Ti2NCl was successfully prepared by growth using titanium slag, nitrogen, and hydrogen chloride gas. x MXene.

[0056] Example 4

[0057] This embodiment provides a method for preparing MXene Ti2CT containing I functional groups using titanium slag, methane, and elemental iodine (I2) gas as raw materials. x (or written as: Ti2CI) x The method (0 < x ≤ 2) is similar to that in Example 1, except that hydrogen chloride gas is replaced with iodine vapor (I2) after heating and sublimation, the reaction temperature is adjusted to 800°C, and the holding time is 30 min.

[0058] X-ray diffraction (XRD) analysis was performed on the purified solid product, and the results are as follows: Figure 7 As shown, the XRD pattern is similar to that of Ti2CCl2 MXene obtained by Lewis acid molten salt etching of the Ti2AlC MAX phase, with a strong diffraction peak appearing at around 6.6 degrees, corresponding to Ti2Cl. x The diffraction peaks of the MXene(002) crystal plane indicate that Ti2CI was successfully prepared by growth using titanium slag, methane, and hydrogen chloride gas. x MXene.

[0059] Example 5

[0060] This embodiment provides a method for preparing MXene Ti2CCl using vanadium slag, methane (CH4), and chlorine (Cl2) as raw materials. x The method, including the following steps:

[0061] 1) Place 10g of vanadium slag powder (sieved through 200 mesh) and 10g of carbon powder in a ceramic boat, put it into a tube furnace, and introduce argon gas into the tube furnace. Set the heating program of the tube furnace to increase the temperature to the reaction temperature of 900 degrees at a rate of 20℃ / min. Argon gas is used as a protective gas during the heating process.

[0062] 2) When the temperature reaches the preset temperature of 900 degrees Celsius, chlorine and methane gases are introduced into the tubular furnace, making the volume fraction of chlorine gas 20% and the volume fraction of methane gas 5%, and the temperature is maintained for 1 hour to carry out the gas-phase growth reaction. During this process, TiO2 in the vanadium slag reacts with carbon powder and chlorine to generate TiCl4 and CO. The gaseous TiCl4 reacts with gaseous methane at high temperature to synthesize solid MXene Ti2CCl. x , deposited in the tubular furnace;

[0063] Meanwhile, under high-temperature conditions, oxides (such as SiO2, Fe2O3, Al2O3, etc.) in vanadium slag react with chlorine (Cl2) to generate gaseous chlorides, which are then removed from the reaction system to remove oxide impurities from the vanadium slag. Taking SiO2 as an example, the reaction is SiO2 + 2Cl2 + C = SiCl4 + CO2; taking Fe2O3 as an example, the reaction is 2Fe2O3 + 6Cl2 + 3C = 4FeCl3 + CO2.

[0064] 3) After the set holding time, change the gas in the tube furnace back to argon, open the lid and air cool to room temperature, then collect the solid products in the tube furnace.

[0065] The purified solid product was analyzed by X-ray diffraction (XRD) using a method similar to that in Example 1, and the results are as follows: Figure 8 As shown, the XRD pattern is similar to that of Ti2CCl obtained by Lewis acid molten salt etching of Ti2AlCMAX phase. x MXene exhibits a strong diffraction peak at around 6.2 degrees, corresponding to Ti₂CCl. x The diffraction peaks of the MXene(002) crystal plane indicate that Ti2CCl was successfully prepared by growth using titanium slag, carbon powder, methane, and chlorine gas. x MXene.

[0066] In this embodiment, reducing agent carbon powder is also added to the raw materials, and chlorine gas is used as the reaction gas. During the gas-phase synthesis reaction, oxide impurities (such as SiO2, Fe2O3, etc.) in the titanium slag can further react with carbon powder and chlorine gas to generate gaseous chlorides (such as SiCl4, FeCl3, etc.), which are then discharged from the system with the gas flow, reducing the difficulty of subsequent impurity removal. The carbon powder is a powder containing elemental carbon; in this embodiment, carbon black powder is used.

[0067] Example 6

[0068] Using a method similar to that in Example 1, the applicant also prepared a series of MXene materials by changing the reaction raw materials and conditions, as shown in the table below:

[0069]

[0070] The foregoing description of specific exemplary embodiments of the invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the invention, as well as various different choices and variations. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. A method for preparing MXene by utilizing titanium slag resources, characterized in that, The method includes: Titanium slag, hydrocarbons and / or nitrogen, and hydrogen halide gas and / or elemental halogen gas are heated to the reaction temperature and then cooled to obtain a solid product containing MXene material.

2. The method as described in claim 1, characterized in that, The hydrocarbon is one or more of alkanes, alkenes, or alkynes; And / or, the hydrocarbon is in a gaseous state; And / or, the hydrogen halide gas is selected from HCl, HBr, or HI; the halogen gas is selected from Cl2, Br2, or I2; And / or, the raw materials used in the method contain carbon materials.

3. The method as described in claim 2, characterized in that, The alkane is selected from one or more of methane, ethane, propane, and butane; And / or, the olefin is selected from one or more of ethylene, propylene, and butene; And / or, the alkyne is selected from acetylene and methylacetylene.

4. The method as described in claim 1, characterized in that, The titanium oxide content in the titanium slag is ≥10% by mass; And / or, the titanium slag contains vanadium oxide; And / or, the titanium slag is selected from one or more of the following: titanium-containing blast furnace slag produced by blast furnace smelting of vanadium-titanium magnetite, molten titanium slag produced by pre-reduction electric furnace smelting, or titanium-rich slag obtained by pre-reduction grinding and separation.

5. The method as described in claim 4, characterized in that, The titanium oxide content in the titanium slag is ≥20% by mass.

6. The method according to any one of claims 1 to 5, characterized in that, The method includes the following more specific steps: Titanium ore slag powder is placed in a high-temperature furnace and heated to the reaction temperature. Then, gaseous hydrocarbon and hydrogen halide gases are introduced and kept at the temperature for a predetermined time. Finally, it is cooled to room temperature to obtain a solid product. Alternatively, titanium slag powder and carbon powder are placed in a high-temperature furnace and heated to the reaction temperature. Chlorine gas is then introduced and the mixture is kept at that temperature for a predetermined time before being cooled to room temperature to obtain a solid product.

7. The method according to any one of claims 1 to 5, characterized in that, The method further includes a purification step to remove impurities from the solid product.

8. The method as described in claim 7, characterized in that, The purification steps include: washing the solid product obtained after the reaction in an acid solution, then washing it with deionized water, drying it, dispersing the product in a non-aqueous solvent, and then separating it by precipitation or centrifugation.

9. The method as described in claim 8, characterized in that, The acid solution is selected from one or more of hydrochloric acid, sulfuric acid, hydrofluoric acid, phosphoric acid, or nitric acid; And / or, the non-aqueous solvent is selected from one or more of propylene carbonate, dimethyl sulfoxide, N-methylpyrrolidone, acetonitrile, N,N-dimethylformamide, N-methylformamide, and isopropanol.

10. The method according to any one of claims 1 to 5, characterized in that, The reaction temperature is between 500°C and 1500°C; And / or, the holding time at the reaction temperature is between 1 min and 24 h.

11. The method as described in claim 10, characterized in that, The reaction temperature is between 650 and 900°C; And / or, the holding time at the reaction temperature is between 30 min and 4 h.

12. The method according to any one of claims 1 to 5, wherein the chemical formula of the MXene material is M2XT. x Or M2X, where M represents titanium and / or vanadium; X represents carbon and / or nitrogen; and T represents a functional group, wherein T includes: At least one of Cl, Br, and I, 0 < x ≤2.

13. The application of the MXene material obtained by the method of any one of claims 1 to 12 in energy, catalysis, adsorption separation, sensing and detection, electromagnetic shielding, biomedicine, gas storage, microwave absorbing material, corrosion resistant material, or superconducting material.

14. The use of slag as a raw material for preparing MXene materials, characterized in that, The slag contains titanium oxide and / or vanadium oxide; Alternatively, the slag may be selected from one or more of the following: titanium-containing blast furnace slag produced by blast furnace smelting of vanadium-titanium magnetite, molten titanium slag produced by pre-reduction electric furnace smelting, or titanium-rich slag obtained by pre-reduction grinding and separation. The use includes the method as described in any one of claims 1 to 12.

15. The use as described in claim 14, characterized in that, The mass content of titanium oxide in the slag is ≥10%.

16. The use as described in claim 14, characterized in that, The mass content of titanium oxide in the slag is ≥20%.

17. The use as described in claim 14, characterized in that, The mass content of titanium oxide in the slag is ≥50%.

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