A method for preparing titanium powder by stepwise reduction of titanium dioxide, aluminum and magnesium

Abstract

The present invention provides a method for preparing titanium powder by stepwise reduction of titanium dioxide, aluminum and magnesium. The method comprises the following steps: firstly, reducing the titanium oxide source with aluminum to obtain TiO x (0.333≤x≤0.5) intermediate powder, and then the obtained TiO x After the intermediate powder is mixed with low-oxygen metallic titanium powder and sintered, magnesium is used as a reducing agent for a second reduction to obtain metallic titanium powder. The method described in the present invention uses aluminum to first remove more than 75% of the oxygen in titanium dioxide, greatly reducing the use of reducing agent magnesium. By mixing with the prepared metallic titanium powder, the firing of the titanium oxide solid solution can be enhanced and the deoxygenation depth of the second reduction can be guaranteed. Moreover, the method uses wet separation technology to dissolve and separate the alumina-enriched by-product phase obtained by aluminum reduction with dilute acid, and no longer uses the conventional high-temperature slag-metal separation method of thermite self-propagating reaction, so the separation efficiency is higher and it is easier to scale up safely.

Description

Technical Field

[0001] The invention relates to the technical field of metal titanium powder preparation, in particular to a method for preparing metal titanium powder through stepwise reduction of titanium dioxide, aluminum and magnesium. Background Art

[0002] Titanium is a rare, active metal with a high melting point and excellent physical and chemical properties. It has become a popular sustainable development material due to its low density, high specific strength, high temperature resistance, strong corrosion resistance and good biocompatibility.

[0003] As another metal with excellent performance and wide applications after iron and aluminum, titanium consumption is 2-3 orders of magnitude lower than aluminum and 5 orders of magnitude lower than steel. This difference in demand is due to the differences in their application areas. Due to cost constraints, titanium in my country is mainly used in high-end fields such as high-end chemical industry, aerospace, and marine engineering, making it difficult to achieve a breakthrough in volume. However, the application of aluminum and steel is closer to civilian fields such as construction, transportation, and home appliances.

[0004] Titanium is a typical chemically active metal. Its strong chemical activity makes it difficult to fully dissociate titanium and oxygen in titanium oxide through direct reduction. The preparation of metallic titanium is more difficult and expensive than that of common metals.

[0005] The HAMR method is a novel magnesium thermal reduction method for TiO2 proposed in recent years. Its key steps include magnesium reduction in a hydrogen atmosphere, heat treatment, and magnesium deoxidation in a hydrogen atmosphere. This method not only has the potential to reduce the smelting cost of titanium metal, but also directly produces high-quality titanium metal powder with low oxygen content, providing a new development direction for titanium powder metallurgy. For example, CN101628337A and CN107639234A disclose methods for producing titanium metal powder by magnesium reduction of titanium dioxide, but both methods still suffer from the problem of high reducing agent costs.

[0006] CN107236869A discloses a method for preparing reduced titanium powder by multi-stage deep reduction, which comprises: uniformly mixing dried titanium dioxide powder and magnesium powder, adding the mixture into a self-propagating reactor, initiating a self-propagating reaction, and obtaining low-valent titanium oxide Ti. x O is dispersed in the MgO matrix, and the intermediate product is leached with hydrochloric acid as the leaching solution, filtered, washed, and vacuum dried to obtain low-valent titanium oxide Ti x The O precursor is mixed evenly with calcium powder, pressed, and placed in a vacuum reduction furnace for secondary deep reduction. The deep reduction product is leached with hydrochloric acid as the leaching liquid to obtain reduced titanium powder, but the cost of the reducing agent is still high.

[0007] Therefore, it is necessary to further reduce the cost of reducing agents in the preparation of metallic titanium powder by reducing titanium dioxide and to achieve a lower oxygen content. Summary of the Invention

[0008] In view of the problems existing in the prior art, the present invention provides a method for preparing metallic titanium powder by the stepwise reduction of titanium dioxide, aluminum and magnesium. The method saves the cost of reducing agents. By combining aluminum reduction, preparation of titanium oxide solid solution and deep reduction of magnesium, not only does it not require the use of high-temperature slag-metal separation methods, but the reaction process is highly controllable, and metallic titanium powder with a low oxygen content can be obtained, which has broader industrial application prospects.

[0009] To achieve this object, the present invention adopts the following technical solutions:

[0010] The present invention provides a method for preparing metallic titanium powder by stepwise reduction of titanium dioxide, aluminum and magnesium, the method comprising the following steps:

[0011] (1) Mixing a calcium titanium source, a first reducing agent and a first auxiliary agent, and sequentially performing a first reduction and a first wet treatment to obtain TiO x Intermediate powder, wherein 0.333≤x≤0.5, and the first reducing agent includes aluminum;

[0012] (2) The TiO x The intermediate powder is mixed with the metal titanium powder returned from step (3), and the obtained mixture is sintered to obtain a titanium oxide solid solution with an oxygen content of ≤8wt%;

[0013] (3) The titanium oxide solid solution is subjected to a second reduction with a second reducing agent and then subjected to a second wet process to obtain metallic titanium powder, wherein the second reducing agent includes magnesium, and a portion of the metallic titanium powder is recycled to step (2).

[0014] The present invention found that the combination of calcium-containing substances and the first auxiliary agent, based on aluminum as a reducing agent, can control the reduced aluminum phase to an aluminum oxide phase soluble in dilute acid, so that TiO can be efficiently separated by the first wet treatment. x Intermediate powder; and TiO x The intermediate powder is mixed with the returned metal titanium powder to prepare a titanium oxide solid solution, thereby strengthening the sintering of the titanium oxide solid solution and ensuring the reduction efficiency of the second reduction.

[0015] Moreover, the present invention does not require the use of a self-propagating reduction method for aluminum reduction, and does not require the subsequent use of a high-temperature slag-metal separation method. Direct wet separation can be performed, greatly improving operational safety.

[0016] The present invention firstly prepares TiO x In the intermediate powder, x is controlled in the range of 0.333≤x≤0.5. On the one hand, it can make full use of the reducing agent aluminum to remove oxygen and reduce the amount of subsequent second reduction magnesium. On the other hand, it is beneficial to inhibit the conversion of aluminum to TiO xAlloying in the intermediate powder ensures the purity of the metal titanium powder. In the second step, the oxygen content is controlled to ≤8wt% by mixing the returned metal titanium powder, which can enhance the firing of the titanium oxide solid solution and ensure the deoxidation depth of the second reduction.

[0017] Preferably, the metallic titanium powder of the present invention refers to titanium powder with an oxygen content of ≤0.3wt%, for example, it can be 0.3wt%, 0.25wt%, 0.2wt%, 0.15wt%, 0.12wt%, 0.10wt% or 0.08wt%.

[0018] In the present invention, the range of x is 0.333 to 0.5, for example, it can be 0.333, 0.34, 0.35, 0.38, 0.4, 0.42, 0.45, 0.47, 0.47, 0.48, 0.49 or 0.5.

[0019] Preferably, the calcium-containing titanium source in step (1) comprises any one or a combination of at least two of a first titanium source, a second titanium source, a third titanium source or a fourth titanium source; the first titanium source is a mixture of titanium dioxide and calcium oxide, the second titanium source is a mixture of calcium oxide and calcined titanium dioxide, the third titanium source is a mixture of a calcined product obtained by mixing calcium oxide and titanium dioxide in a stoichiometric ratio of CaTiO3 and calcium oxide, and the fourth titanium source is a mixture obtained by mixing calcium oxide and titanium dioxide in a stoichiometric ratio exceeding CaTiO3 and calcining.

[0020] Preferably, the calcination temperature of the second titanium source, the third titanium source or the fourth titanium source is independently 1000~1400°C, for example, it can be 1000°C, 1044°C, 1088°C, 1132°C, 1176°C, 1220°C, 1264°C, 1308°C, 1352°C or 1400°C, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0021] Preferably, the molar ratio of calcium in the calcium-containing titanium source to the first reducing agent in step (1) is 0.6-2:1, for example, it can be 0.6:1, 0.75:1, 0.9:1, 1.05:1, 1.2:1, 1.35:1, 1.5:1, 1.65:1, 1.8:1 or 2:1, etc.

[0022] Preferably, the molar ratio of the first reducing agent to titanium in the calcium titanium source is 1 to 1.22:1, for example, it can be 1:1, 1.04:1, 1.07:1, 1.11:1, 1.14:1, 1.18:1, 1.20:1, 1.21:1 or 1.22:1.

[0023] The present invention further preferably has the molar ratio of calcium, titanium and the first reducing agent in the first reduction be within the above range, which can ensure that the first reduction reaches the set oxygen content level while avoiding the formation of an insoluble aluminum phase.

[0024] Preferably, in step (1), the first auxiliary agent comprises any one of anhydrous CaCl2, KCl, NaCl, CaCl2-KCl eutectic salt, CaCl2-NaCl eutectic salt, CaCl2-LiCl eutectic salt, KCl-NaCl eutectic salt, LiCl-NaCl eutectic salt, LiCl-KCl eutectic salt, AlCl3-KCl eutectic salt or AlCl3-NaCl eutectic salt, or a combination of at least two thereof, wherein typical but non-limiting combinations are: a combination of CaCl2 and KCl, a combination of CaCl2 and NaCl, a combination of CaCl2 and a CaCl2-NaCl eutectic salt, a combination of CaCl2 and a CaCl2-LiCl eutectic salt, a combination of CaCl2 and an AlCl3-NaCl eutectic salt, a combination of a CaCl2-NaCl eutectic salt and a CaCl2-LiCl eutectic salt, a combination of a CaCl2-NaCl eutectic salt and a CaCl2-KCl eutectic salt, and a combination of a CaCl2-KCl eutectic salt and an AlCl3-NaCl eutectic salt.

[0025] The present invention further prefers calcium-containing substances as the first auxiliary agent, which can better control the formation of aluminum phase that is easily soluble in dilute acid and avoid aluminum in TiO x Residue in the intermediate powder, while ensuring TiO x The oxygen content in the intermediate powder reaches the set level.

[0026] Preferably, the weight ratio of the first auxiliary agent to the titanium in the calcium titanium source calculated as TiO2 is 0.05~3:1, for example, it can be 0.05:1, 0.1:1, 0.15:1, 0.2:1, 0.5:1, 1.0:1, 1.5:1, 2.0:1, 2.5:1, 2.8:1 or 3.0:1, etc.

[0027] Preferably, the first reducing agent is in the form of powder, chips or granules, or a combination of at least two of them, wherein typical but non-limiting combinations are a combination of powder and chips, a combination of granules and chips, and a combination of powder and granules.

[0028] Preferably, the temperature of the first reduction in step (1) is 700-1200°C, for example, 700°C, 777°C, 855°C, 932°C, 1010°C, 1087°C, 1100°C, 1140°C, 1160°C or 1200°C, etc., but is not limited to the listed values, and other values ​​not listed within the range are also applicable.

[0029] Preferably, the first reduction time is 0.3 to 24 hours, for example, 0.3 hours, 0.5 hours, 3.0 hours, 5.6 hours, 8.2 hours, 10.7 hours, 13.5 hours, 16.1 hours, 18.8 hours, 21.5 hours or 24 hours, but is not limited to the listed values, and other values ​​not listed within the range are also applicable.

[0030] Preferably, the first reducing atmosphere comprises a vacuum or protective atmosphere.

[0031] Preferably, the first reducing protective atmosphere comprises any one or a combination of at least two of argon, hydrogen or helium, wherein typical but non-limiting combinations are: a combination of argon and hydrogen, a combination of argon and helium, a combination of hydrogen and helium, and a combination of argon, hydrogen and helium.

[0032] Preferably, the first wet treatment in step (1) comprises: slurrying the product of the first reduction with water and / or acid solution to obtain a slurry; the slurry is successively subjected to pH adjustment and solid-liquid separation, and the obtained solid phase is successively washed and dried to obtain TiO x (0.333≤x≤0.5) intermediate powder.

[0033] Preferably, the second wet treatment in step (3) includes: slurrying the product of the second reduction with water and / or acid solution to obtain a slurry; the slurry is successively pH-adjusted and solid-liquid separated, and the obtained solid phase is successively washed and dried to obtain metallic titanium powder.

[0034] Preferably, the pH of the acid solution in the first wet treatment and the second wet treatment is independently ≥0.5, for example, it can be 0.5, 0.7, 0.9, 1, 1.2, 1.4, 1.5, 1.7, 1.9 or 2, etc., but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0035] Preferably, the liquid-to-solid ratio of the slurry in the first wet treatment and the second wet treatment is independently 1 to 100:1 mL / g, for example, it can be 1:1 mL / g, 12:1 mL / g, 23:1 mL / g, 34:1 mL / g, 45:1 mL / g, 56:1 mL / g, 67:1 mL / g, 78:1 mL / g, 89:1 mL / g or 100:1 mL / g, but is not limited to the listed values, and other values ​​not listed within the range are also applicable.

[0036] Preferably, the acid used for pH adjustment in the first wet treatment and the second wet treatment is independently hydrochloric acid.

[0037] Preferably, the pH of the slurry is independently controlled to be ≥ 0.8 in the pH adjustment in the first wet treatment and the second wet treatment, for example, it can be 0.8, 1.1, 1.3, 1.6, 1.8, 2.1, 2.3, 2.6, 2.8 or 3, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0038] Preferably, the pH of the slurry after pH adjustment in the first wet treatment and the second wet treatment is independently 1.5 to 3.0, for example, it can be 1.5, 1.7, 1.9, 2, 2.2, 2.4, 2.5, 2.7, 2.9 or 3.0, but is not limited to the listed values, and other values ​​not listed within the range are also applicable.

[0039] In the present invention, in order to prevent TiO x (0.333≤x≤0.5) The intermediate powder and the titanium metal powder undergo a dissolution reaction with the acid during the pH adjustment process. The pH value of the slurry during the pH adjustment process is preferably controlled to be above 0.8. The pH adjustment is considered to be completed when the pH value stabilizes between 1.5 and 3.0 and no longer changes.

[0040] Preferably, the washing temperature in the first wet treatment and the second wet treatment is independently 0~60℃, for example, it can be 0℃, 7℃, 14℃, 20℃, 27℃, 34℃, 40℃, 47℃, 54℃ or 60℃, etc., but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0041] Preferably, the drying temperature in the first wet treatment and the second wet treatment is independently ≤60°C, for example, 40°C, 43°C, 45°C, 47°C, 49°C, 52°C, 54°C, 56°C, 58°C or 60°C, etc., but is not limited to the listed values, and other values ​​not listed in this range are also applicable. The drying method is one of atmospheric pressure or vacuum drying at no more than 60°C, or freeze drying. Controlling the drying temperature in the present invention can effectively prevent excessive oxidation of the titanium powder surface, which is more conducive to controlling the oxygen content level of the final metallic titanium powder.

[0042] Preferably, the TiO x The mass ratio of the intermediate powder to the metallic titanium powder is 1:0.25 to 10, for example, it can be 1:0.25, 1:0.3, 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9 or 1:10, etc., but is not limited to the listed values, and other values ​​not listed within the range are also applicable.

[0043] Preferably, the sintering temperature is 800-1200°C, for example, it can be 800°C, 850°C, 900°C, 950°C, 1000°C, 1050°C, 1100°C or 1200°C, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0044] Preferably, the sintering time is 0.25~24h, for example, it can be 0.25h, 0.5h, 1h, 1.5h, 2h, 2.5h, 3h, 4h, 5h, 6h, 7h, 8h, 10h, 12h, 15h, 18h, 20h or 24h, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0045] Preferably, the sintering atmosphere is a vacuum or protective atmosphere.

[0046] Preferably, the protective atmosphere for sintering comprises any one of hydrogen, argon or helium, or a combination of at least two of them, wherein typical but non-limiting combinations are a combination of hydrogen and argon, a combination of helium and argon, and a combination of hydrogen and helium.

[0047] Preferably, the mixing in step (2) includes dry powder mixing, or the mixing process includes first mixing TiO x The intermediate powder is ground into slurry to make the TiO x The particle size of the intermediate powder is below 10µm, and then the slurry and the titanium metal powder are mixed, stirred evenly and dried, or the mixing process includes firstly mixing TiO x The intermediate powder is ground into slurry to make the TiO x The particle size of the intermediate powder is below 6 μm, and the slurry is atomized to the surface of the metal titanium powder by air flow and dried, or the mixing process includes the step of adding TiO x The intermediate powder and the titanium metal powder are mixed, crushed and granulated.

[0048] Preferably, the dry powder mixing includes any one of three-dimensional mixing, V-type mixing or drum mixing.

[0049] Preferably, the crushing method includes any one of ball milling, stirred milling or air flow milling, or a combination of at least two of them, wherein a typical but non-limiting combination is a combination of ball milling and stirred milling, a combination of air flow milling and stirred milling, or a combination of ball milling and air flow milling.

[0050] Preferably, the granulation method includes any one of spray granulation, drum granulation or compression granulation.

[0051] Preferably, the mass ratio of the second reducing agent to the titanium oxide solid solution in step (3) is 0.033~0.6:1, for example, it can be 0.033:1, 0.04:1, 0.05:1, 0.1:1, 0.15:1, 0.2:1, 0.25:1, 0.3:1, 0.35:1, 0.4:1, 0.45:1, 0.5:1 or 0.6:1, etc., but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0052] Preferably, the second reducing agent is in the form of powder, chips or granules, or a combination of at least two of them, wherein typical but non-limiting combinations are a combination of powder and chips, a combination of granules and chips, and a combination of powder and granules.

[0053] Preferably, a second auxiliary agent is added during the second reduction.

[0054] Preferably, the second auxiliary agent includes any one of anhydrous MgCl2, MgCl2-CaCl2 eutectic salt, MgCl2-NaCl eutectic salt or MgCl2-KCl eutectic salt, or a combination of at least two thereof, wherein typical but non-limiting combinations are: a combination of MgCl2 and a MgCl2-CaCl2 eutectic salt, a combination of MgCl2 and a MgCl2-NaCl eutectic salt, a combination of MgCl2 and a MgCl2-KCl eutectic salt, a combination of a MgCl2-KCl eutectic salt and a MgCl2-NaCl eutectic salt, and a combination of a MgCl2-KCl eutectic salt and a MgCl2-CaCl2 eutectic salt.

[0055] Preferably, the weight ratio of the second auxiliary agent to the Ti-O solid solution is 0.05~3:1, for example, it can be 0.05:1, 0.1:1, 0.15:1, 0.2:1, 0.5:1, 1.0:1, 1.5:1, 2.0:1, 2.5:1, 2.8:1 or 3.0:1, etc.

[0056] Preferably, the temperature of the second reduction is 650-900°C, for example, 650°C, 677°C, 705°C, 732°C, 760°C, 787°C, 815°C, 842°C, 868°C or 900°C, etc., but is not limited to the listed values, and other values ​​not listed within this range are also applicable.

[0057] Preferably, the second reduction time is 0.25 to 48 hours, for example, 0.25 hours, 1.0 hours, 5.0 hours, 10.5 hours, 15 hours, 21 hours, 28 hours, 35 hours, 40 hours or 48 hours, but is not limited to the listed values, and other values ​​not listed within the range are also applicable.

[0058] Preferably, the second reducing atmosphere includes a hydrogen-argon mixed atmosphere or a pure hydrogen atmosphere.

[0059] Preferably, the volume fraction of hydrogen in the hydrogen-argon mixed atmosphere is 5 to 100%, for example, it can be 5%, 10%, 15%, 20%, 30%, 40%, 50%, 60%, 80% or 100%, etc., but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0060] Preferably, the method further comprises: subjecting the metallic titanium powder obtained by the second wet treatment in step (3) to dehydrogenation treatment.

[0061] Hydrogen regulates the thermodynamic stability of the Ti-O solid solution. With the help of interstitial hydrogen, oxygen in the titanium oxide solid solution can be efficiently removed by magnesium. However, the second deep reduction process also results in hydrogen in the titanium powder. When the application scenario of the titanium powder product has limitations on hydrogen content, dehydrogenation treatment is performed.

[0062] Preferably, the temperature of the dehydrogenation treatment is 500-1000°C, for example, 500°C, 600°C, 700°C, 800°C, 850°C, 900°C, 950°C or 1000°C, etc., but is not limited to the listed values, and other values ​​not listed within this range are also applicable.

[0063] Preferably, the atmosphere of the dehydrogenation treatment includes vacuum or protective atmosphere.

[0064] Preferably, the protective atmosphere of the dehydrogenation treatment includes argon and / or helium.

[0065] As a preferred technical solution of the present invention, the method comprises the following steps:

[0066] (1) mixing a calcium titanium source, a first reducing agent, and a first auxiliary agent, wherein the molar ratio of calcium in the calcium titanium source to the first reducing agent is 0.6-2:1, the molar ratio of the first reducing agent to titanium in the calcium titanium source is 1-1.22:1, and the weight ratio of the first auxiliary agent to titanium in the calcium titanium source as TiO2 is 0.05-3:1, and performing a first reduction in vacuum or protective atmosphere at 700-1200°C for 0.3-24h to obtain a first reduced product;

[0067] The product of the first reduction is slurried with water and / or an acid solution with a pH value of ≥0.5, with a liquid-solid ratio of 1-100:1 mL / g, to obtain a slurry; the slurry is successively pH-adjusted, wherein the pH of the slurry is controlled to be ≥0.8 during the pH adjustment, and the pH of the slurry after pH adjustment is stabilized at 1.5-3.0, and solid-liquid separation is performed, and the obtained solid phase is successively washed at 0-60°C and dried at ≤60°C to obtain TiO x Intermediate powder, where 0.333≤x≤0.5;

[0068] (2) Mix the TiO x The mixture of the intermediate powder and the titanium powder returned from step (3) is sintered at 800-1200°C for 0.25-24h in vacuum or protective atmosphere to obtain a titanium oxide solid solution with an oxygen content of ≤8wt%;

[0069] (3) The titanium oxide solid solution is subjected to a second reduction with a second reducing agent and a second auxiliary agent in a hydrogen-argon mixed atmosphere or a pure hydrogen atmosphere at 650-900°C for 0.25-48h, wherein the mass ratio of the second reducing agent to the titanium oxide solid solution is 0.033-0.6:1, and the weight ratio of the second auxiliary agent to the titanium oxide solid solution is 0.05-3:1, to obtain a second reduced product;

[0070] The product of the second reduction is slurried with water and / or an acid solution with a pH ≥ 0.5, with a liquid-solid ratio of 1-100:1 mL / g, to obtain a slurry; the slurry is successively pH-adjusted, and the pH of the slurry is controlled to be ≥ 0.8 during the pH adjustment. The pH of the slurry after pH adjustment is stabilized at 1.5-3.0, and solid-liquid separation is performed. The obtained solid phase is successively washed at 0-60°C and dried at ≤ 60°C to obtain metallic titanium powder.

[0071] In the present invention, the oxygen content in the aluminum reduction, i.e., the first reduction product, can be better controlled at 10-14.3%, thereby effectively inhibiting the conversion of aluminum to TiO x The solid solution in the intermediate powder and the return of low-oxygen titanium powder can reduce the sintering temperature and energy consumption.

[0072] The present invention has no particular limitation on the solid-liquid separation in the above process. Any device and method for solid-liquid separation known to those skilled in the art can be used, and can also be adjusted according to the actual process. For example, it can be filtration, centrifugation or sedimentation separation, or a combination of different methods.

[0073] The present invention has no particular limitation on the drying process. Any drying device and method known to those skilled in the art can be used. The drying method can also be adjusted according to the actual process. For example, it can be air drying, vacuum drying, oven drying or freeze drying, or a combination of different methods.

[0074] Compared with the prior art, the present invention has at least the following beneficial effects:

[0075] (1) The method for preparing titanium powder by stepwise reduction of titanium dioxide, aluminum and magnesium provided by the present invention is to first reduce the TiO2 raw material with aluminum, and then xThe intermediate powder is mixed with titanium metal powder to prepare a titanium oxide solid solution, which is then deeply reduced. Compared with the full magnesium reduction process of oxygen in titanium dioxide, this method can save more than 60% of the cost of the reducing agent required for the oxygen removed by aluminum. The overall reducing agent cost can be reduced by 22,060 yuan per ton of titanium metal powder, which is only 55% of the original full magnesium reduction process. In addition, the overall process has high deoxidation efficiency.

[0076] (2) The method for preparing metallic titanium powder by the stepwise reduction of titanium dioxide, aluminum and magnesium provided by the present invention obtains an aluminum oxide-enriched by-product phase that is easily soluble in dilute acid by adding CaO and a first auxiliary agent and controlling an appropriate ratio. The separation of the titanium product and the by-product phase is more thorough, and the temperature requirement for the reduction process is greatly reduced;

[0077] (3) The method for preparing metallic titanium powder by stepwise reduction of titanium dioxide, aluminum and magnesium provided by the present invention can ensure that the oxygen content in the prepared titanium powder is low, the oxygen content is less than 0.3wt%, and under optimal conditions, the oxygen content is less than 0.1wt%. BRIEF DESCRIPTION OF THE DRAWINGS

[0078] Figure 1 It is a flow chart of a method for preparing metallic titanium powder by stepwise reduction of titanium dioxide, aluminum and magnesium provided in a specific embodiment of the present invention. DETAILED DESCRIPTION

[0079] The technical solution of the present invention will be further described below with reference to the accompanying drawings and through specific implementation methods.

[0080] The present invention is further described in detail below. However, the following examples are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims.

[0081] As a specific embodiment of the present invention, a method for preparing titanium powder by stepwise reduction of titanium dioxide, aluminum and magnesium is provided. The flow chart of the method is as follows: Figure 1 As shown, the specific steps include:

[0082] (1) mixing a calcium-titanium source (calcined or uncalcined titanium oxide and calcium oxide), a first reducing agent, and a first auxiliary agent, and sequentially performing a first reduction to obtain a first reduced product;

[0083] The product of the first reduction is subjected to a first wet treatment, wherein the first wet treatment comprises slurrying the product of the first reduction with water and / or acid solution to obtain a slurry; the slurry is pH-adjusted and subjected to solid-liquid separation, and the obtained solid phase is sequentially washed and dried to obtain TiO x Intermediate powder, where 0.333≤x≤0.5;

[0084] (2) The TiO xThe intermediate powder is mixed with the metal titanium powder returned from step (3), and the obtained mixture is sintered to obtain a titanium oxide solid solution with an oxygen content of ≤8wt%;

[0085] (3) The titanium oxide solid solution is subjected to a second reduction by a second reducing agent and a second auxiliary agent to obtain a second reduced product;

[0086] The product of the second reduction is subjected to a second wet treatment, wherein the second wet treatment comprises slurrying the product of the second reduction with water and / or acid to obtain a slurry; the slurry is pH-adjusted and subjected to solid-liquid separation, and the obtained solid phase is sequentially washed and dried to obtain metallic titanium powder, and a portion of the solid phase is returned to step (2);

[0087] Optionally, the metal titanium powder is partially dehydrogenated to obtain dehydrogenated metal titanium powder as the output titanium powder.

[0088] Example 1

[0089] This embodiment provides a method for preparing metallic titanium powder by stepwise reduction of titanium dioxide, aluminum and magnesium, the method comprising the following steps:

[0090] (1) mixing a calcium titanium source (a mixture of calcium oxide and calcined titanium dioxide), aluminum powder and a CaCl2-NaCl eutectic salt, wherein the molar ratio of calcium in the calcium titanium source to aluminum powder is 1.3:1, the molar ratio of aluminum powder to titanium in the calcium titanium source is 1.0:1, and the weight ratio of the CaCl2-NaCl eutectic salt to titanium in the calcium titanium source as TiO2 is 1.5:1, and subjecting the mixture to a first reduction at 790°C for 10 hours in a helium atmosphere to obtain a first reduced product;

[0091] The product of the first reduction was slurried with hydrochloric acid solution at a pH of 0.5, with a liquid-to-solid ratio of 40:1 mL / g, to obtain a slurry; the slurry was successively pH-adjusted, and the pH of the slurry was controlled to be ≥ 0.8 during the pH adjustment. The pH of the slurry after pH adjustment was stabilized at 1.8, and filtered. The obtained solid phase was successively washed with water at 45°C and dried at 55°C to obtain TiO x middle powder;

[0092] (2) Directly dry-mix the TiO x The mixture of the intermediate powder and the metal titanium powder returned from step (3) is sintered at 1200°C for 6 hours in an argon atmosphere to obtain a titanium oxide solid solution;

[0093] (3) The titanium oxide solid solution is subjected to a second reduction with magnesium powder and MgCl2-KCl eutectic salt in a hydrogen-argon mixed atmosphere (the volume fraction of hydrogen is 70%) at 850°C for 2 hours, wherein the mass ratio of magnesium powder to titanium oxide solid solution is 0.3:1, and the weight ratio of MgCl2-KCl eutectic salt to titanium oxide solid solution is 2:1, to obtain a second reduced product;

[0094] The product of the second reduction is slurried in water with a liquid-to-solid ratio of 5:1 mL / g to obtain a slurry; the slurry is successively pH-adjusted, and the pH of the slurry is controlled to be ≥0.8 during the pH adjustment. The pH of the slurry after pH adjustment is stabilized at 1.6, and is filtered. The obtained solid phase is successively washed with water at 50°C and dried at 40°C to obtain metallic titanium powder.

[0095] Example 2

[0096] This embodiment provides a method for preparing metallic titanium powder by stepwise reduction of titanium dioxide, aluminum and magnesium, the method comprising the following steps:

[0097] (1) mixing a calcium titanium source (a mixture of a calcined product obtained by mixing calcium oxide and titanium dioxide in a stoichiometric ratio of CaTiO3 and calcium oxide), aluminum powder, and anhydrous CaCl2, wherein the molar ratio of calcium in the calcium titanium source to aluminum powder is 0.6:1, the molar ratio of aluminum powder to titanium in the calcium titanium source is 1.22:1, and the weight ratio of anhydrous CaCl2 to titanium in the calcium titanium source as TiO2 is 3:1, and the mixture is first reduced at 1200°C for 0.25h in an argon atmosphere to obtain a first reduced product;

[0098] The product of the first reduction was slurried with hydrochloric acid solution at a pH of 1.5, with a liquid-solid ratio of 100:1 mL / g, to obtain a slurry; the slurry was successively pH-adjusted, and the pH of the slurry was controlled to be ≥ 0.8 during the pH adjustment. The pH of the slurry after pH adjustment was stabilized at 1.5, and filtered. The obtained solid phase was successively washed with water at 40°C and dried at 0°C to obtain TiO x middle powder;

[0099] (2) First, the TiO x The intermediate powder is ground into slurry to make the TiO x The particle size of the intermediate powder is below 10µm. Then the slurry is mixed with the titanium powder returned from step (3), stirred evenly and dried. x The mass ratio of the intermediate powder to the metallic titanium powder is 1:4, and the resulting mixture is sintered at 800°C for 24 hours under vacuum conditions to obtain a titanium oxide solid solution;

[0100] (3) The titanium oxide solid solution is subjected to a second reduction reaction at 900°C for 0.25h in a hydrogen-argon mixed atmosphere (the volume fraction of hydrogen is 10%) with magnesium powder and MgCl2 salt, wherein the mass ratio of magnesium powder to titanium oxide solid solution is 0.05:1 and the weight ratio of MgCl2 salt to titanium oxide solid solution is 0.05:1, to obtain a second reduced product;

[0101] The product of the second reduction is slurried with hydrochloric acid solution with a pH of 1.0 and a liquid-to-solid ratio of 20:1 mL / g to obtain a slurry; the slurry is successively pH-adjusted, and the pH of the slurry is controlled to be ≥0.8 during the pH adjustment. The pH of the slurry after pH adjustment is stabilized at 3.0, and is filtered. The obtained solid phase is successively washed with water at 20°C and dried at 45°C to obtain metallic titanium powder.

[0102] Example 3

[0103] This embodiment provides a method for preparing metallic titanium powder by stepwise reduction of titanium dioxide, aluminum and magnesium, the method comprising the following steps:

[0104] (1) mixing a calcium titanium source (a calcined product obtained by mixing calcium oxide and titanium dioxide in a stoichiometric ratio exceeding CaTiO3), aluminum powder, and a CaCl2-LiCl eutectic salt, wherein the molar ratio of calcium in the calcium titanium source to aluminum powder is 2:1, the molar ratio of aluminum powder to titanium in the calcium titanium source is 1:1, and the weight ratio of the CaCl2-LiCl eutectic salt to titanium in the calcium titanium source as TiO2 is 1.22:1, and subjecting the mixture to a first reduction at 700°C for 24 hours under vacuum conditions to obtain a first reduced product;

[0105] The product of the first reduction was slurried with hydrochloric acid solution at a pH of 1.0, with a liquid-to-solid ratio of 25:1 mL / g, to obtain a slurry; the slurry was successively pH-adjusted, and the pH of the slurry was controlled to be ≥1.0 during the pH adjustment. The pH of the slurry after pH adjustment was stabilized at 3.0, and filtered. The obtained solid phase was successively washed with water at 60°C and dried at 15°C to obtain TiO x middle powder;

[0106] (2) First, TiO x The intermediate powder is ground into slurry to make the TiO x The particle size of the intermediate powder is below 6 μm, and the slurry is atomized to the surface of the metal titanium powder by air flow and dried. x The mass ratio of the intermediate powder to the metal titanium powder returned from step (3) is 1:0.25, and the obtained mixture is sintered at 1000°C for 8 hours under an argon atmosphere to obtain a titanium oxide solid solution;

[0107] (3) The titanium oxide solid solution is subjected to a second reduction with magnesium powder and MgCl2-KCl eutectic salt in a pure hydrogen atmosphere at 650°C for 24 hours, wherein the mass ratio of magnesium powder to titanium oxide solid solution is 0.15:1, and the weight ratio of MgCl2-KCl eutectic salt to titanium oxide solid solution is 3:1, to obtain a second reduced product;

[0108] The product of the second reduction is slurried with hydrochloric acid solution with a pH of 1.5 and a liquid-to-solid ratio of 10:1 mL / g to obtain a slurry; the slurry is successively pH-adjusted, and the pH of the slurry is controlled to be ≥0.8 during the pH adjustment. The pH of the slurry after pH adjustment is stabilized at 1.5, and is filtered. The obtained solid phase is successively washed with water at 25°C and dried at 55°C to obtain metallic titanium powder.

[0109] Example 4

[0110] This embodiment provides a method for preparing metallic titanium powder by stepwise reduction of titanium dioxide, aluminum and magnesium. The method is the same as that of Example 1, except that the CaCl2-NaCl eutectic salt is replaced by AlCl3-KCl eutectic salt in step (1).

[0111] Example 5

[0112] This embodiment provides a method for preparing metallic titanium powder by stepwise reduction of titanium dioxide, aluminum and magnesium. The method is the same as that of Example 1, except that in step (1), the weight ratio of the CaCl2-NaCl eutectic salt to the titanium in the calcium titanium source calculated as TiO2 is 3.5:1.

[0113] Example 6

[0114] This embodiment provides a method for preparing metallic titanium powder by stepwise reduction of titanium dioxide, aluminum and magnesium. The method is the same as that of Example 1, except that in step (1), the weight ratio of the CaCl2-NaCl eutectic salt to the titanium in the calcium titanium source calculated as TiO2 is 0.01:1.

[0115] Example 7

[0116] This embodiment provides a method for preparing metallic titanium powder by stepwise reduction of titanium dioxide, aluminum and magnesium. The method is the same as that of embodiment 1 except that the MgCl2-KCl eutectic salt is replaced by CaCl2-KCl eutectic salt in step (3).

[0117] Example 8

[0118] This embodiment provides a method for preparing titanium powder by stepwise reduction of titanium dioxide, aluminum and magnesium. The method includes replacing the step of direct dry powder mixing in step (2) with the following steps: x The intermediate powder and the metal titanium powder are mixed, crushed by ball milling, and spray granulated and sintered to obtain a titanium oxide solid solution with a nearly spherical morphology. Others are the same as in Example 1.

[0119] Example 9

[0120] This embodiment provides a method for preparing metallic titanium powder by stepwise reduction of titanium dioxide, aluminum and magnesium. The method is the same as that of embodiment 1 except that the atmosphere of the second reduction in step (3) is replaced by a helium atmosphere.

[0121] Example 10

[0122] This embodiment provides a method for preparing metallic titanium powder by stepwise reduction of titanium dioxide, aluminum and magnesium. The method is the same as that of embodiment 1 except that the molar ratio of calcium to aluminum powder in the calcium-containing titanium source in step (1) is 0.2:1.

[0123] Example 11

[0124] This embodiment provides a method for preparing metallic titanium powder by stepwise reduction of titanium dioxide, aluminum and magnesium. The method is the same as that of embodiment 1 except that the molar ratio of calcium to aluminum powder in the calcium-containing titanium source in step (1) is 2.5:1.

[0125] Comparative Example 1

[0126] This comparative example provides a method for preparing metallic titanium powder by stepwise reduction of titanium dioxide, aluminum and magnesium. The method is the same as Example 1 except that the calcium-containing titanium source in step (1) is replaced by a non-calcium-containing titanium source, that is, calcined titanium dioxide is directly used.

[0127] Comparative Example 2

[0128] This comparative example provides a method for preparing titanium powder by reduction. The method is the same as Example 1 except that the mixing step (2) is not performed. That is, TiO x The intermediate powder is sintered and then subjected to a second reduction, and the parameters and conditions of the second reduction are the same as those in Example 1.

[0129] The content of other elements was determined by ICP-OES and the content of TiO was determined by X-ray diffraction. x The value of x in the intermediate powder is obtained, and the oxygen content of the final metal titanium powder is measured using an ONH analyzer. The cost of the reducing agent consumed for each ton of metal titanium powder produced is calculated, where the current market price of magnesium is RMB 40,000 per ton and that of aluminum is RMB 20,000 per ton.

[0130] The test results, calculation results and effects of the above embodiments and comparative examples are shown in Tables 1 and 2.

[0131] Table 1

[0132] <![CDATA[TiO x The value of x in the intermediate powder]]> Oxygen content in titanium oxide solid solution (wt%) Oxygen content of titanium powder (wt%) Aluminum consumption / ton of titanium powder Magnesium consumption / ton of titanium powder Reducing agent cost / ton of titanium powder Example 1 0.5 7.94 0.18 0.5625 0.6300 3.645 Example 2 0.333 2.01 0.25 0.6863 0.2777 2.483 Example 3 0.333 8.00 0.09 0.6863 0.2083 2.206

[0133] Table 2

[0134] The product of the first reduction is separated by the first wet method Oxygen content in titanium oxide solid solution (wt%) Oxygen content of titanium powder (wt%) Example 4 <![CDATA[Ti2O, that is, x = 0.5]]> 7.94 0.18 Example 5 <![CDATA[Ti2O, that is, x = 0.5]]> 7.94 0.18 Example 6 <![CDATA[Ti2O and weakly acid-insoluble aluminum phase make it difficult to implement subsequent steps]]> / / Example 7 <![CDATA[Ti2O, that is, x = 0.5]]> 7.94 0.82 Example 8 <![CDATA[Ti2O, i.e., x = 0.5]]> 7.94 0.12 Example 9 <![CDATA[Ti2O, that is, x = 0.5]]> 7.94 2.42 Example 10 <![CDATA[Ti2O and the weak acid-insoluble aluminum phase make it difficult to implement subsequent steps]]> / / Example 11 <![CDATA[Ti2O, that is, x = 0.5]]> 7.94 0.18 Comparative Example 1 <![CDATA[Ti2O, Ti3Al, and weak-acid-insoluble Al2O3 make it impossible to carry out subsequent steps]]> / / Comparative Example 4 <![CDATA[Ti2O, that is, x = 0.5]]> / 1.78

[0135] “ / ” in the table indicates that there is no relevant data.

[0136] The following points can be seen from Tables 1 and 2:

[0137] (1) Based on Examples 1 to 3, it can be seen that the method for preparing titanium powder by stepwise reduction of titanium dioxide, aluminum and magnesium provided by the present invention can produce titanium powder with an oxygen content of less than 0.3%, and the cost of the reducing agent can be reduced by RMB 22,060 per ton of titanium powder, which is only 55% of the cost of the original full magnesium reduction process.

[0138] (2) From Example 1 and Examples 5-6, it can be seen that the present invention can reduce the waste of the first auxiliary agent and avoid the formation of a weakly acid-insoluble aluminum phase by controlling the weight ratio of the first auxiliary agent to the titanium in the calcium-containing titanium source in terms of TiO2 within a specific range, which is beneficial to the subsequent wet separation.

[0139] (3) From the combination of Example 1, Example 7 and Example 9, it can be seen that the magnesium reduction in Example 1 adopts a second auxiliary agent containing magnesium and a hydrogen-containing atmosphere. Compared with Example 7 using CaCl2-KCl eutectic salt as the second auxiliary agent and Example 9 using a hydrogen-free atmosphere, the oxygen content in the titanium metal powder in Example 1 is 0.18 wt%, while the oxygen contents in Examples 7 and 9 are as high as 0.82 wt% and 2.42 wt%, respectively. This shows that the present invention improves the reduction effect and further reduces the oxygen content in the titanium metal powder by adopting a second auxiliary agent containing magnesium and performing the magnesium reduction step in a hydrogen-containing atmosphere.

[0140] (4) Combining Example 1 and Example 8, it can be seen that the spray granulation sintering method used in Example 8 can further reduce the oxygen content in the metal titanium powder compared with Example 1;

[0141] (5) From Example 1, Examples 10-11, and Comparative Example 1, it can be seen that the molar ratio of calcium to aluminum powder in the calcium titanium source in Example 1 is 1.3:1, compared with 0.2:1 and 2.5:1 in Examples 10-11, respectively. In Comparative Example 1, which does not contain calcium, the first reduced product in Example 1 can be wet-processed to obtain TiO with x=0.5. x The intermediate powder, while in Comparative Example 1 and Example 10, due to the formation of weakly acid-insoluble aluminum phase, subsequent wet separation is difficult, and in Example 11, there is excess CaO ineffective consumption. This shows that the present invention can effectively ensure that the reduction by-products are soluble in weak acid by controlling the molar ratio of calcium to aluminum powder within a specific range;

[0142] (5) From Example 1 and Comparative Example 2, it can be seen that in Comparative Example 2, the oxygen content of the final metal titanium powder is as high as 1.78 wt %. This shows that the present invention can obtain low-oxygen metal titanium powder through only two reduction steps by returning part of the low-oxygen titanium powder, and the process is short.

[0143] While the present invention is described through the above-described embodiments to illustrate the detailed structural features of the present invention, the present invention is not limited to these detailed structural features, nor does it necessarily rely on these detailed structural features for implementation. Those skilled in the art should understand that any improvements to the present invention, equivalent replacements for selected components, additions of auxiliary components, and selection of specific embodiments, etc., fall within the scope of protection and disclosure of the present invention.

Claims

1. A method for preparing metallic titanium powder by stepwise reduction of titanium dioxide, aluminum and magnesium, characterized in that: The method comprises the following steps: (1) Mixing a calcium titanium source, a first reducing agent and a first auxiliary agent, and sequentially performing a first reduction and a first wet treatment to obtain TiO x Intermediate powder, wherein 0.333≤x≤0.5, and the first reducing agent includes aluminum; (2) The TiO x The intermediate powder is mixed with the metal titanium powder returned from step (3), and the obtained mixture is sintered to obtain a titanium oxide solid solution with an oxygen content of ≤8wt%; (3) The titanium oxide solid solution is subjected to a second reduction by a second reducing agent, and then subjected to a second wet process to obtain metallic titanium powder, wherein the second reducing agent includes magnesium, and the metallic titanium powder is partially recycled to step (2); The molar ratio of calcium in the calcium-titanium source to the first reducing agent is 0.6 to 2:1; The molar ratio of the first reducing agent to the titanium in the calcium-containing titanium source is 1 to 1.22:1; In step (1), the first auxiliary agent includes any one of anhydrous CaCl2, KCl, NaCl, CaCl2-KCl eutectic salt, CaCl2-NaCl eutectic salt, CaCl2-LiCl eutectic salt, KCl-NaCl eutectic salt, LiCl-NaCl eutectic salt, LiCl-KCl eutectic salt, AlCl3-KCl eutectic salt or AlCl3-NaCl eutectic salt, or a combination of at least two thereof; The weight ratio of the first auxiliary agent to the titanium in the calcium titanium source calculated as TiO2 is 0.05 to 3:1; The first wet treatment in step (1) includes: slurrying the product of the first reduction with water and / or acid solution to obtain slurry; the slurry is successively pH-adjusted and solid-liquid separated, and the obtained solid phase is successively washed and dried to obtain TiO x middle powder; In step (3), the mass ratio of the second reducing agent to the titanium oxide solid solution is 0.033-0.6:

1.

2. The method according to claim 1, characterized in that The first reducing agent may be in a powdery, crumbly or granular form, or in a combination of at least two of the forms.

3. The method according to claim 1, characterized in that The temperature of the first reduction in step (1) is 700-1200°C; The first reduction time is 0.3 to 24 hours; The first reducing atmosphere includes vacuum or protective atmosphere; The first reducing protective atmosphere includes any one of argon, hydrogen or helium, or a combination of at least two of them.

4. The method according to claim 1, wherein The second wet treatment in step (3) includes: the product of the second reduction is slurried with water and / or acid solution to obtain a slurry; the slurry is successively pH-adjusted and solid-liquid separated, and the obtained solid phase is successively washed and dried to obtain metallic titanium powder.

5. The method according to claim 4, characterized in that The pH of the acid solution in the first wet treatment and the second wet treatment is independently ≥ 0.5; The liquid-to-solid ratio of the slurry in the first wet treatment and the second wet treatment is independently 1 to 100:1 mL / g; The acid used for pH adjustment in the first wet treatment and the second wet treatment is independently hydrochloric acid; The pH of the slurry is independently controlled to be ≥ 0.8 during the pH adjustment in the first wet treatment and the second wet treatment; The pH of the slurry after pH adjustment in the first wet treatment and the second wet treatment is independently 1.5 to 3.0; The washing temperatures in the first wet treatment and the second wet treatment are each independently 0 to 60°C; The drying temperatures in the first wet treatment and the second wet treatment are each independently ≤ 60°C.

6. The method according to claim 1, characterized in that TiO x The mass ratio of the intermediate powder to the metal titanium powder is 1:0.25~10.

7. The method according to claim 1, characterized in that The sintering temperature is 800-1200°C; The sintering time is 0.25~24h; The sintering atmosphere is a vacuum or protective atmosphere; The protective atmosphere for sintering includes any one of hydrogen, argon or helium, or a combination of at least two of them.

8. The method according to claim 1, characterized in that The mixing in step (2) includes dry powder mixing, or the mixing process includes first mixing TiO x The intermediate powder is ground into slurry to make the TiO x The particle size of the intermediate powder is below 10µm, and then the slurry and the titanium metal powder are mixed, stirred evenly and dried, or the mixing process includes firstly mixing TiO x The intermediate powder is ground into slurry to make the TiO x The particle size of the intermediate powder is below 6 μm, and the slurry is atomized to the surface of the metal titanium powder by air flow and dried, or the mixing process includes the step of adding TiO x The intermediate powder and the titanium metal powder are mixed, crushed and granulated.

9. The method according to claim 8, characterized in that The dry powder mixing includes any one of three-dimensional mixing, V-type mixing or drum mixing; The crushing method includes any one of ball milling, stirred milling or air flow milling, or a combination of at least two of them; The granulation method includes any one of spray granulation, drum granulation or compression granulation.

10. The method according to claim 1, characterized in that The second reducing agent may be in a powdery, crumbly or granular form, or in a combination of at least two of the forms.

11. The method according to claim 1, wherein Adding a second auxiliary agent during the second reduction; The second auxiliary agent includes any one or a combination of at least two of anhydrous MgCl2, MgCl2-CaCl2 eutectic salt, MgCl2-NaCl eutectic salt or MgCl2-KCl eutectic salt; The weight ratio of the second auxiliary agent to the Ti—O solid solution is 0.05-3:

1.

12. The method according to claim 1, characterized in that The temperature of the second reduction is 650-900° C.; The second reduction time is 0.25~48h; The second reducing atmosphere includes a hydrogen-argon mixed atmosphere or a pure hydrogen atmosphere; The volume fraction of hydrogen in the hydrogen-argon mixed atmosphere is 5-100%.

13. The method according to claim 1, wherein The method further comprises: dehydrogenating the titanium powder obtained by the second wet process in step (3) The temperature of the dehydrogenation treatment is 500-1000°C; The atmosphere of the dehydrogenation treatment includes vacuum or protective atmosphere; The protective atmosphere of the dehydrogenation treatment includes argon and / or helium.

14. The method according to claim 1, wherein The method comprises the following steps: (1) mixing a calcium titanium source, a first reducing agent, and a first auxiliary agent, wherein the molar ratio of calcium in the calcium titanium source to the first reducing agent is 0.6-2:1, the molar ratio of the first reducing agent to titanium in the calcium titanium source is 1-1.22:1, and the weight ratio of the first auxiliary agent to titanium in the calcium titanium source as TiO2 is 0.05-3:1, and performing a first reduction in vacuum or protective atmosphere at 700-1200°C for 0.3-24h to obtain a first reduced product; The product of the first reduction is slurried with water and / or an acid solution with a pH value of ≥0.5, with a liquid-solid ratio of 1-100:1 mL / g, to obtain a slurry; the slurry is successively pH-adjusted, wherein the pH of the slurry is controlled to be ≥0.8 during the pH adjustment, and the pH of the slurry after pH adjustment is stabilized at 1.5-3.0, and solid-liquid separation is performed, and the obtained solid phase is successively washed at 0-60°C and dried at ≤60°C to obtain TiO x Intermediate powder, where 0.333≤x≤0.5; (2) Mix the TiO x The mixture of the intermediate powder and the titanium powder returned from step (3) is sintered at 800-1200°C for 0.25-24h in vacuum or protective atmosphere to obtain a titanium oxide solid solution with an oxygen content of ≤8wt%; (3) The titanium oxide solid solution is subjected to a second reduction with a second reducing agent and a second auxiliary agent in a hydrogen-argon mixed atmosphere or a pure hydrogen atmosphere at 650-900°C for 0.25-48h, wherein the mass ratio of the second reducing agent to the titanium oxide solid solution is 0.033-0.6:1, and the weight ratio of the second auxiliary agent to the titanium oxide solid solution is 0.05-3:1, to obtain a second reduced product; The product of the second reduction is slurried with water and / or an acid solution with a pH ≥ 0.5, with a liquid-solid ratio of 1-100:1 mL / g, to obtain a slurry; the slurry is successively pH-adjusted, and the pH of the slurry is controlled to be ≥ 0.8 during the pH adjustment. The pH of the slurry after pH adjustment is stabilized at 1.5-3.0, and solid-liquid separation is performed. The obtained solid phase is successively washed at 0-60°C and dried at ≤ 60°C to obtain metallic titanium powder.

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