Preparation method of sponge titanium

Abstract

This disclosure provides at least one embodiment of a method for preparing sponge titanium, comprising: pretreating bauxite tailings to obtain a first mixture; acid-treating the first mixture and filtering it to obtain a second mixture; placing the second mixture in a reaction vessel containing an alkaline substance to react, thereby converting ferrous titanate into titanate and ferric oxide or ferrous hydroxide to obtain a third mixture; filtration of the third mixture to obtain a first solid phase and a first liquid phase, and drying and grinding the first solid phase; calcining the dried and ground first solid phase to form elemental iron, and performing magnetic separation to remove the elemental iron; adding an acidic substance to the first liquid phase to react and obtain metatitanic acid colloid, and washing the metatitanic acid colloid; and sequentially subjecting the metatitanic acid colloid to calcination, chlorination, and displacement reactions to obtain sponge titanium. The sponge titanium obtained by this preparation method has high purity.

Description

Technical Field

[0001] The embodiments of this disclosure relate to a method for preparing sponge titanium. Background Technology

[0002] Bauxite tailings are the main solid waste generated during alumina production, containing valuable metallic elements such as titanium, iron, and silicon. Titanium mainly exists in the form of ilmenite (FeTiO3) or rutile (TiO2), possessing high recovery value. Traditional titanium extraction methods, such as the sulfuric acid process or chlorination process, suffer from high energy consumption, significant pollution, and complex processes, making it difficult to economically and efficiently process low-grade titanium resources. Therefore, developing a green and efficient titanium extraction technology is of great significance for realizing the resource utilization of bauxite tailings. Summary of the Invention

[0003] A method for preparing sponge titanium involves pretreating and acid-treating solid waste bauxite tailings to remove excess impurities, followed by a subcritical alkaline-thermal reaction to convert titanium into easily extractable titanates. The titanates are then further purified to obtain sponge titanium. The sponge titanium obtained by this method has high purity and can realize high-value-added utilization of bauxite tailings.

[0004] A method for preparing sponge titanium includes: pretreating bauxite tailings to obtain a first mixture, wherein the pretreating includes: crushing and grinding the bauxite tailings; adding carbon and alkaline compound powder to the crushed and ground bauxite tailings; mixing evenly; calcining under anaerobic conditions at 800℃~850℃ to obtain elemental iron and silicates; removing the elemental iron by magnetic separation; and removing silicon by filtration; acid treating the first mixture; and filtering to obtain a second mixture, wherein the acid treatment includes: adding hydrochloric acid or nitric acid to the first mixture to remove alkaline calcium compounds, aluminum compounds, and magnesium compounds. The mixture is a compound of potassium and potassium; the second mixture is placed in a reaction vessel containing an alkaline substance to react, so as to convert ferric titanate into titanate and ferric oxide or ferrous hydroxide, to obtain a third mixture; the third mixture is filtered to obtain a first solid phase and a first liquid phase, and the first solid phase is dried and ground; the dried and ground first solid phase is calcined to form elemental iron, and magnetic separation is performed to remove the elemental iron; an acidic substance is added to the first liquid phase to react, to obtain metatitanic acid colloid, and the metatitanic acid colloid is washed; the metatitanic acid colloid is subjected to calcination, chlorination and displacement reaction in sequence to obtain sponge titanium.

[0005] In the mixture of bauxite tailings, carbon, and alkaline compound powder, the mass percentage of carbon is 8% to 12%, and the mass percentage of alkaline compound powder is 15% to 25%.

[0006] The carbon includes at least one of biochar, coke, and carbon powder; the alkaline compound powder includes at least one of sodium carbonate, potassium carbonate, and sodium hydroxide.

[0007] The conditions for placing the second mixture into a reaction vessel containing an alkaline substance are as follows: reaction temperature of 200℃~300℃, reaction pressure of 1 MPa~10 MPa, the alkaline substance being sodium hydroxide or potassium hydroxide, and the molar concentration of the alkaline substance being 5 mol / L~10 mol / L.

[0008] The step of calcining the dried and ground first solid phase to form elemental iron includes calcining at a temperature of 600℃~650℃ for 30min~60min.

[0009] The acidic substance added to the first liquid phase includes at least one of hydrochloric acid and nitric acid.

[0010] The calcination of the metatitanic acid colloid includes converting the metatitanic acid colloid into titanium dioxide in air at a temperature of 800°C to 1000°C.

[0011] The chlorination reaction includes reacting the titanium dioxide with chlorine and carbon at a temperature of 800℃~1100℃ to convert the titanium dioxide into titanium tetrachloride.

[0012] The displacement reaction includes reducing titanium tetrachloride to sponge titanium in a protective gas environment and at a temperature of 850°C to 950°C.

[0013] The reduction of titanium tetrachloride to sponge titanium includes: using elemental magnesium for a displacement reaction. Attached Figure Description

[0014] To more clearly illustrate the technical solutions of the embodiments of this disclosure, the accompanying drawings of the embodiments will be briefly described below. Obviously, the drawings described below only relate to some embodiments of this disclosure and are not intended to limit this disclosure.

[0015] Figure 1 A flowchart illustrating a method for preparing sponge titanium according to at least one embodiment of this disclosure;

[0016] Figure 2 This is another schematic flowchart illustrating a method for preparing sponge titanium, provided for at least one embodiment of this disclosure.

[0017] Figure 3 Microscopic images of sponge titanium formed by the preparation method in at least one embodiment of this disclosure; and

[0018] Figure 4 This is a scanning electron microscope image of sponge titanium formed by the preparation method in at least one embodiment of this disclosure.

[0019] Figure 5 An XRF image of sponge titanium provided in at least one embodiment of this disclosure. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this disclosure. All other embodiments obtained by those skilled in the art based on the described embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.

[0021] Subcritical water technology is an emerging green chemical method; the subcritical state of water is defined as a temperature of 100°C. o C ~374 o C, with pressures ranging from 1 MPa to 22.1 MPa, utilizes the unique physicochemical properties of water in its subcritical state, such as low dielectric constant, high diffusivity, and strong dissolving power, to significantly improve mineral decomposition and metal leaching efficiency. Compared to traditional acid / alkali high-temperature melting methods, subcritical methods offer advantages such as milder reaction conditions, lower reagent consumption, and environmental friendliness, and have shown promising application prospects in the extraction of rare earth metals, lithium metals, and nickel metals. However, research on subcritical extraction of titanium from bauxite tailings remains relatively scarce, especially regarding how to optimize the reaction system. For example, the concentration of alkaline substances, reaction temperature, and reaction time should be considered to improve the selective leaching rate of titanium metal and reduce the co-dissolution problem of impurities such as iron and silicon.

[0022] The preparation of sponge titanium mainly relies on the magnesothermic reduction method, whose core steps include raw material processing, reduction reaction, and post-processing. The specific process is as follows: Titanium-rich minerals (such as rutile or ilmenite) are used as raw materials, purified, and chlorinated to convert into titanium tetrachloride. Titanium tetrachloride is liquid at room temperature, facilitating storage and transportation. Next, titanium tetrachloride and metallic magnesium are injected into a closed reactor. Under high temperature, magnesium reacts with titanium tetrachloride to produce titanium metal and magnesium chloride. Due to the need for precise control of reaction conditions, the titanium deposits as a loose, porous, sponge-like solid, rather than a dense mass. After the reaction, the sponge titanium needs to be separated from the byproducts. Residual magnesium chloride and unreacted magnesium are removed by methods such as vacuum distillation or acid washing, ultimately yielding pure sponge titanium. The entire production process requires extremely high levels of equipment sealing and temperature control to avoid impurities or safety accidents.

[0023] Subcritical methods can be used to extract sponge titanium from bauxite tailings. This involves pretreating and acid-treating the bauxite tailings to remove excess impurities, followed by a subcritical alkaline-thermal reaction that converts titanium into easily extractable titanates. These titanates are then further purified to obtain sponge titanium. This method uses bauxite tailings as raw material to extract high-purity sponge titanium, enabling high-value utilization of bauxite tailings.

[0024] This disclosure provides at least one embodiment of a method for preparing sponge titanium, the method comprising: pretreating bauxite tailings to obtain a first mixture; acid-treating the first mixture and filtering it to obtain a second mixture; reacting the second mixture in a reaction vessel containing an alkaline substance to convert ferric titanate into titanate and ferric oxide or ferrous hydroxide to obtain a third mixture; filtration of the third mixture to obtain a first solid phase and a first liquid phase, and drying and grinding the first solid phase; calcining the dried and ground first solid phase to form elemental iron, and then... Magnetic separation is used to remove elemental iron; an acidic substance is added to the first liquid phase to react and obtain metatitanic acid colloid, which is then washed; the metatitanic acid colloid is then subjected to calcination, chlorination, and displacement reactions to obtain sponge titanium. This preparation method involves pretreating and acid-treating solid waste bauxite tailings to remove excess impurities, followed by a subcritical alkaline-thermal reaction to convert titanium into easily extractable titanates, which are then further purified to obtain sponge titanium. The sponge titanium obtained by this method has high purity and can realize high-value-added utilization of bauxite tailings.

[0025] Figure 1 The flowchart illustrates a method for preparing sponge titanium according to at least one embodiment of this disclosure. Figure 2 This is another schematic flowchart illustrating a method for preparing sponge titanium provided in at least one embodiment of the present disclosure, as shown below. Figure 1 and Figure 2As shown, the preparation method of this sponge titanium includes the following steps.

[0026] Step S101: Pre-treat the bauxite tailings to obtain a first mixture.

[0027] The main components of bauxite tailings include Al2O3, SiO2, Fe2O3, K2O, and TiO2, with small amounts of CaO, MgO, SO3, and other components. Specifically, the mass percentages of Al2O3, SiO2, Fe2O3, K2O, TiO2, CaO, MgO, and SO3 are 43.98%, 36.03%, 10.55%, 3.57%, 3.08%, 0.89%, 0.57%, and 0.78%, respectively, with other components comprising 0.55%. For example, SO3 readily volatilizes under heating conditions and is therefore easily removed without the need for specialized reactions.

[0028] The main components of bauxite tailings are oxides. Other components include ferrous oxide.

[0029] In step S101, the pretreatment of bauxite tailings includes: crushing and grinding the bauxite tailings, reducing the iron oxide and ferrous oxide in the bauxite tailings to elemental iron, removing elemental iron by magnetic separation; converting the silicon oxide in the bauxite tailings into silicates, and removing silicon by filtration.

[0030] Bauxite tailings can be crushed and ground by grinding them in a mortar with a grinding rod to grind them into powder with a certain mesh size.

[0031] The process of reducing iron oxide and ferrous oxide in bauxite tailings to elemental iron and converting silicon oxide in bauxite tailings to silicates includes: adding carbon and alkaline compound powder to the crushed and ground bauxite tailings, mixing them evenly, and then calcining them at 800℃~850℃ under anaerobic conditions to obtain elemental iron and silicates.

[0032] The mixture of bauxite tailings, carbon, and alkaline compound powder can be stirred evenly with a stirring rod, placed in a crucible, and then placed in a muffle furnace. Calcination is then performed under a protective gas atmosphere (e.g., nitrogen or helium), at temperatures such as 800°C, 810°C, 820°C, 830°C, 840°C, or 850°C. For example, the temperature of the muffle furnace can be rapidly increased to 800°C–850°C using a programmed temperature rise method.

[0033] The above steps utilize carbon powder to reduce the iron components in bauxite tailings, dissociating them from a non-magnetic polymer state to generate magnetic iron substances. The iron impurities are then removed through magnetic separation.

[0034] In the mixture of bauxite tailings, carbon, and alkaline compound powder, the mass percentage of carbon is 8% to 12%, and the mass percentage of alkaline compound powder is 15% to 25%, to ensure an alkaline environment and sufficient amount of reducing agent carbon.

[0035] In the embodiments of this disclosure, expressions of numerical ranges such as "8%-12%" include both extreme values, which will not be repeated below.

[0036] In one example, carbon includes at least one of biochar, coke, and carbon powder.

[0037] In one example, the alkaline compound powder includes at least one of sodium carbonate, potassium carbonate, and sodium hydroxide.

[0038] Pretreatment of bauxite tailings to remove silicon and most of the iron components involves the following main chemical reaction: γNa₂CO₃ + M x (SiO3) y →Na 2y (SiO3) y +M x O y +yCO2↑, 2(ɑ-Fe2O3)+3C→4Fe+3CO2↑ and 2FeO+C→2Fe+CO2↑.

[0039] Based on the above chemical reactions, oxidized iron is reduced to elemental iron, which can then be removed by magnetic attraction. Silicon oxide is converted into water-soluble silicates, which can be removed by dissolving them in water.

[0040] Step S102: The first mixture is acid-treated and filtered to obtain the second mixture.

[0041] Acid treatment of the first mixture includes adding hydrochloric acid or nitric acid to the first mixture to remove alkaline compounds of calcium, aluminum, magnesium and potassium, i.e., to remove alkaline compounds such as Al2O3, K2O, CaO and MgO.

[0042] Step S103: The second mixture is placed in a reaction vessel containing an alkaline substance to react, so as to convert ferric titanate into titanate and ferric oxide or ferrous hydroxide, to obtain the third mixture.

[0043] The second mixture is placed in a reaction vessel containing an alkaline substance, and the reaction conditions are as follows: reaction temperature of 200℃~300℃, reaction pressure of 1 MPa~10 MPa, the alkaline substance being sodium hydroxide or potassium hydroxide, and the molar concentration of the alkaline substance being 5 mol / L~10 mol / L. This reaction is a subcritical alkaline-thermal reaction.

[0044] Ferric titanate consists of divalent iron ions (Fe2+) 2+ ) and titanate ions (TiO3) 2- It is composed of titanium, which has a +4 oxidation state, and its corresponding oxyacid is titanic acid (H4TiO4 or H2TiO3), which is a weak acid and its acidity is significantly stronger than its basicity. Therefore, when ferric titanate dissolves in water, its hydrolysis tendency is mainly acidic.

[0045] The second mixture was placed in a reaction vessel containing an alkaline substance and reacted under high temperature and high pressure for a period of time. The main chemical reaction that occurred was: FeTiO3 + NaOH + O2 → Na2TiO3 + Fe2O3 + H2O.

[0046] FeTiO3 + NaOH → Na2TiO3 + Fe(OH) 2。

[0047] As can be seen from the above chemical reactions, the titanium element in ferric titanate is converted into water-soluble titanate, and the iron element is converted into ferric oxide or ferrous hydroxide, in preparation for the subsequent formation of magnetic elemental iron.

[0048] Step S104: The third mixture is filtered to obtain a first solid phase and a first liquid phase, and the first solid phase is dried and ground.

[0049] A vacuum pump, or a circulating water vacuum pump, or a water-pumped air pump can be used to provide negative pressure to achieve rapid filtration.

[0050] Step S105: The first solid phase after drying and grinding is calcined to form elemental iron, and then magnetic separation is performed to remove elemental iron.

[0051] In one example, calcining the dried and ground first solid phase to form elemental iron involves calcining at a temperature of 600°C to 650°C for 30 to 60 minutes to allow the iron oxide or ferrous hydroxide to react sufficiently to form elemental iron.

[0052] Step S106: Add an acidic substance to the first liquid phase to react and obtain metatitanic acid colloid, and wash the metatitanic acid colloid.

[0053] The acidic substance added to the first liquid phase includes at least one of hydrochloric acid and nitric acid.

[0054] Metatitanic acid colloids can be washed multiple times with distilled water.

[0055] Theoretically, adding an acidic substance to the first liquid phase will result in the following chemical reaction: Na₂TiO₃ + 2H₂O + +(n+1)H2O→H4TiO 4` nH2O + 2Na + Since original titanic acid is unstable and will form metatitanic acid, the actual chemical reaction that will occur is: Na₂TiO₃ + 2H₂O + +(n-1)H₂O→TiO 2` nH2O↓+2Na + .

[0056] Step S107: The metatitanic acid colloid is subjected to calcination, chlorination and displacement reaction in sequence to obtain sponge titanium.

[0057] The calcination of metatitanic acid colloid includes converting it into titanium dioxide in air at a temperature of 800℃~1000℃. The corresponding chemical reaction formula is as follows:

[0058] TiO 2` nH2O→TiO2+H2O.

[0059] The above chlorination reaction includes reacting titanium dioxide with chlorine and carbon at a temperature of 800℃~1100℃ to convert titanium dioxide into titanium tetrachloride. The corresponding chemical reaction formula is as follows:

[0060] TiO2 + Cl2 + C → TiCl4 + CO2.

[0061] The above displacement reaction includes reducing titanium tetrachloride to sponge titanium in a protective gas environment and at a temperature of 850℃~950℃.

[0062] The reduction of titanium tetrachloride to sponge titanium includes: a displacement reaction using elemental magnesium, with the corresponding chemical reaction formula being:

[0063] TiCl4(g)+Mg(l)→Ti(s)+MgCl2(l).

[0064] The method for preparing sponge titanium provided in the embodiments of this disclosure involves pretreating and acid-treating solid waste bauxite tailings to remove excess impurities, followed by a subcritical alkaline-thermal reaction to convert titanium into easily extractable titanates. The titanates are then further purified to obtain sponge titanium. The sponge titanium obtained by this method has high purity and can realize high-value-added utilization of bauxite tailings.

[0065] The following specific embodiments describe the preparation method of sponge titanium provided in the present disclosure.

[0066] Example 1:

[0067] Step S1: Crush and grind the bauxite tailings, add carbon powder and sodium hydroxide. In the mixture of bauxite tailings, carbon powder and sodium hydroxide, the mass percentage of carbon powder is 10% and the mass percentage of sodium hydroxide is 20%. After mixing evenly, roast at 830℃ to reduce the iron oxide and ferrous oxide in the bauxite tailings to elemental iron. Remove the elemental iron by wet magnetic separation. Convert the silicon oxide in the bauxite tailings to silicates, filter to remove silicon, and obtain the first mixture.

[0068] The above steps utilize carbon powder to reduce the iron components in bauxite tailings, dissociating them from a non-magnetic polymer state to generate magnetic iron substances. Through magnetic separation, iron impurities are removed, and silicon elements are removed simultaneously.

[0069] Step S2: The first mixture is then subjected to acid treatment, and the mixture is filtered to obtain the second mixture.

[0070] The above steps can dissolve all minerals such as calcium, aluminum, magnesium, and potassium in bauxite tailings in the water system using acid, and then remove calcium, aluminum, magnesium, and potassium elements through filtration.

[0071] Step S3: The second mixture is placed in a reaction vessel containing sodium hydroxide for reaction at a temperature of 250°C and a pressure of 5 MPa, i.e., the reaction is carried out under high temperature and high pressure for 30 minutes.

[0072] The above steps cause the ferritic titanate in the bauxite tailings to react with sodium hydroxide, generating easily extractable titanates and ferrous hydroxide.

[0073] Step S4: Filter to obtain the first solid phase, and dry and grind it.

[0074] The above steps can yield high-purity titanates, which can then be dried and ground into smaller particles to facilitate subsequent purification operations.

[0075] Step S5: The first solid phase after drying and grinding is calcined at a temperature of 630℃ for 45 minutes and then subjected to magnetic separation.

[0076] The above steps decompose non-magnetic ferrous hydroxide into magnetic ferric oxide through calcination, followed by magnetic separation to remove the iron component.

[0077] Step S6: Add hydrochloric acid to the non-magnetic substance to obtain a colloid, and wash it multiple times;

[0078] Through the above steps, the titanate replaces the original titanate, and the salt impurities are removed by repeated washing.

[0079] Step S7: The colloid is subjected to calcination, chlorination reaction, and displacement reaction to obtain high-purity sponge titanium.

[0080] Through the above steps, calcination converts the original titanic acid into titanium dioxide; then, through chlorination, titanium dioxide is converted into titanium chloride; and high-purity sponge titanium is extracted by displacing titanium with an active metal.

[0081] For example, Figure 3 This is a microscopic image of the sponge titanium formed by the preparation method in at least one embodiment of this disclosure. Figure 4 Here are scanning electron microscope (SEM) images of sponge titanium formed by the preparation method in at least one embodiment of this disclosure, such as... Figure 3 and Figure 4 As shown, the surface of the titanium sponge has some pores, exhibiting a loose state. XRD analysis requires the sample to be in powder or smooth surface, but titanium sponge has high hardness, making it impossible to pulverize the sample using traditional methods. Therefore, a handheld X-ray fluorescence spectrometry (XRF) detector was used to determine its composition and content. Figure 5 Here is an XRF detection image of sponge titanium provided in at least one embodiment of this disclosure, such as... Figure 5 As shown, the sponge titanium has a mass percentage content of 98.99%, the manganese has a mass percentage content of 0.127%, and the iron has a mass percentage content of 0.749%.

[0082] Comparative Example 1

[0083] Based on Example 1, the wet magnetic separation in step S1 is replaced with dry magnetic separation, which results in the silicon component not being dissolved and removed by water. In step S2, it reacts with acid to produce silica gel precipitate, which makes it impossible to completely remove the coating of other metal impurities. It is necessary to hydrolyze and then redissolve to continue the reaction.

[0084] The raw materials used in Comparative Example 1 were 100g of bauxite tailings, 203ml of hydrochloric acid, 3.62g of sponge titanium, and a purity of 45.02%, which is too low.

[0085] The X-ray fluorescence spectrometry (XRF) report shows that the product in Comparative Example 1 includes silicon (19.56% by mass), iron (20.35% by mass), calcium (5.31% by mass), aluminum (8.97% by mass), titanium (45.02% by mass), and other elements (0.79% by mass).

[0086] Comparative Example 2

[0087] Based on Example 1, removing 10% of the carbon powder in step S1 prevents a large amount of non-magnetic iron components from being reduced, resulting in a significant increase in the amount of acid used in step S2.

[0088] The raw materials used in Comparative Example 2 were 100g of bauxite tailings, 613ml of hydrochloric acid, 2.88g of sponge titanium, and 98.59% purity of sponge titanium. The acid consumption was too high.

[0089] The X-ray fluorescence spectrometry (XRF) report shows that the product in Comparative Example 2 includes silicon (0.02% by mass), iron (0.34% by mass), calcium (0.1% by mass), aluminum (0.05% by mass), titanium (98.59% by mass), and other elements (0.9% by mass).

[0090] Comparative Example 3

[0091] Based on Example 1, concentrated sulfuric acid is used in step S2, causing the titanium component to be dissolved by sulfuric acid into titanium oxysulfate, which is removed along with other impurities.

[0092] The raw materials used in Comparative Example 3 were 100g of bauxite tailings, 170ml of sulfuric acid, 0.35g of sponge titanium, and 98.65% purity of sponge titanium, resulting in a very low yield.

[0093] The X-ray fluorescence spectrometry (XRF) report shows that the products in Comparative Example 3 include silicon (0.05% by mass), iron (0.65% by mass), calcium (0.08% by mass), aluminum (0.09% by mass), titanium (98.65% by mass), and other elements (0.48% by mass).

[0094] Comparative Example 4

[0095] Without performing magnetic separation in step S5, the prepared titanium product will contain a large amount of iron impurities, as in Example 1.

[0096] The raw materials used in Comparative Example 4 were 100g of bauxite tailings, 237ml of sulfuric acid, 3.21g of sponge titanium, and 88.06% purity of sponge titanium, which contained many impurities.

[0097] The X-ray fluorescence spectrometry (XRF) report shows that the products in Comparative Example 4 include silicon (0.11% by mass), iron (11.26% by mass), calcium (0.16% by mass), aluminum (0.15% by mass), titanium (88.06% by mass), and other elements (0.26% by mass).

[0098] Therefore, wet magnetic separation is required in step S1, and concentrated sulfuric acid cannot be used for acid treatment.

[0099] The above description is merely a specific embodiment of this disclosure, but the scope of protection of this disclosure is not limited thereto. The scope of protection of this disclosure should be determined by the scope of protection of the claims.

Claims

1. A method for preparing sponge titanium, comprising: A pretreatment of bauxite tailings is performed to obtain a first mixture, wherein the pretreatment includes: crushing and grinding the bauxite tailings; adding carbon and alkaline compound powder to the crushed and ground bauxite tailings; mixing evenly; calcining under anaerobic conditions at 800℃~850℃ to obtain elemental iron and silicates; removing the elemental iron by wet magnetic separation; and removing silicon by filtration. The first mixture is subjected to acid treatment, and the mixture is filtered to obtain a second mixture. The acid treatment includes adding hydrochloric acid or nitric acid to the first mixture to remove alkaline calcium compounds, aluminum compounds, magnesium compounds and potassium compounds. The second mixture is placed in a reaction vessel containing an alkaline substance to react, so as to convert ferric titanate into titanate and ferric oxide or ferrous hydroxide, to obtain a third mixture; The third mixture is subjected to vacuum filtration to obtain a first solid phase and a first liquid phase, and the first solid phase is dried and ground. The first solid phase after drying and grinding is calcined to form elemental iron, and then magnetic separation is performed to remove the elemental iron. An acidic substance is added to the first liquid phase to react and obtain metatitanic acid colloid, which is then washed. The titanium sponge was obtained by sequentially subjecting the metatitanic acid colloid to calcination, chlorination, and displacement reactions. In the mixture of bauxite tailings, carbon, and alkaline compound powder, the mass percentage of carbon is 8% to 12%, and the mass percentage of alkaline compound powder is 15% to 25%. The conditions for placing the second mixture into a reaction vessel containing an alkaline substance are as follows: reaction temperature of 200℃~300℃, reaction pressure of 1 MPa~10 MPa, the alkaline substance being sodium hydroxide or potassium hydroxide, and the molar concentration of the alkaline substance being 5 mol / L~10 mol / L.

2. The preparation method according to claim 1, wherein, The carbon includes at least one of biochar, coke, and carbon powder; The alkaline compound powder includes at least one of sodium carbonate, potassium carbonate, and sodium hydroxide.

3. The preparation method according to claim 1, wherein, The step of calcining the dried and ground first solid phase to form elemental iron includes calcining at a temperature of 600℃~650℃ for 30min~60min.

4. The preparation method according to claim 1, wherein, The acidic substance added to the first liquid phase includes at least one of hydrochloric acid and nitric acid.

5. The preparation method according to claim 1, wherein, The calcination of the metatitanic acid colloid includes converting the metatitanic acid colloid into titanium dioxide in air at a temperature of 800°C to 1000°C.

6. The preparation method according to claim 5, wherein, The chlorination reaction includes reacting the titanium dioxide with chlorine and carbon at a temperature of 800℃~1100℃ to convert the titanium dioxide into titanium tetrachloride.

7. The preparation method according to claim 6, wherein, The displacement reaction includes reducing titanium tetrachloride to sponge titanium in a protective gas environment and at a temperature of 850°C to 950°C.

8. The preparation method according to claim 7, wherein, The reduction of titanium tetrachloride to sponge titanium includes: using elemental magnesium for a displacement reaction.

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