Method for preparing molybdenum powder based on spray granulation precursor and molybdenum powder

Abstract

The invention relates to the technical field of nano powder material preparation, in particular to a method for preparing molybdenum powder based on a spray granulation precursor and the molybdenum powder. The method for preparing the molybdenum powder comprises the steps that ammonium molybdate and a pore forming agent are dissolved in ultrapure water at the room temperature, and mixed slurry is obtained; carrying out spray granulation treatment on the mixed slurry to obtain composite powder particles containing the pore-forming agent and ammonium molybdate; the composite powder particles are placed in an oxygen-containing atmosphere to be roasted, and superfine nano molybdenum trioxide is obtained; placing the superfine nano molybdenum trioxide in a hydrogen atmosphere for primary reduction treatment to obtain superfine molybdenum dioxide powder; and the superfine molybdenum dioxide powder is subjected to second-stage reduction treatment, the superfine molybdenum powder is obtained, and the reduction conditions of the first-stage reduction treatment and the second-stage reduction treatment are different. According to the preparation method, the superfine molybdenum powder with good uniformity and dispersity can be prepared.

Description

Technical Field

[0001] The disclosed embodiments relate to the technical field of nano-powder material preparation, and specifically to a method for preparing molybdenum powder based on a spray granulation precursor and the molybdenum powder. Background Art

[0002] Molybdenum powder is a key basic material for the production of molybdenum alloys and molybdenum products. Its particle size, dispersibility, purity and morphology directly affect the quality and performance of molybdenum processed products. With the development of my country's economy and the adjustment of industrial structure, molybdenum has also developed rapidly in emerging industries such as semiconductors and 5G (5th Generation Mobile Communication Technology) communications. While broadening its application areas and market prospects, higher requirements are placed on its product quality. Compared with traditional molybdenum powder, ultrafine / nano molybdenum powder has the characteristics of large specific surface area, enhanced chemical activity of interface atoms and molecules, and high absorption capacity, which significantly changes the physical, mechanical and chemical properties of the material and has broad market prospects in the field of high-end manufacturing.

[0003] However, although the traditional method of preparing molybdenum dioxide and molybdenum powder is low-cost and simple in process, the resulting molybdenum powder is also limited in its application in high-end manufacturing due to its coarse grains, poor dispersibility and uneven particle size. High-end molybdenum powder still relies heavily on imports.

[0004] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present disclosure, and therefore may include information that does not constitute the prior art known to ordinary technicians in the field. Summary of the invention

[0005] The purpose of the present disclosure is to provide a method for preparing molybdenum powder based on a spray granulation precursor and molybdenum powder, thereby improving the uniformity and dispersibility of the prepared ultrafine molybdenum powder at least to a certain extent.

[0006] According to one aspect of the present disclosure, a method for preparing molybdenum powder based on a spray granulation precursor is provided, comprising: dissolving ammonium molybdate and a pore-forming agent in ultrapure water at room temperature to obtain a mixed slurry; spray granulating the mixed slurry to obtain composite powder particles containing the pore-forming agent and ammonium molybdate; calcining the composite powder particles in an oxygen-containing atmosphere to obtain ultrafine nano molybdenum trioxide; subjecting the ultrafine nano molybdenum trioxide to a one-stage reduction treatment in a hydrogen atmosphere to obtain ultrafine molybdenum dioxide powder; and subjecting the ultrafine molybdenum dioxide powder to a two-stage reduction treatment to obtain ultrafine molybdenum powder, wherein the reduction conditions of the one-stage reduction treatment and the two-stage reduction treatment are different.

[0007] In an exemplary embodiment of the present disclosure, the temperature of the spray granulation treatment is 100-200° C.; wherein a spray dryer is used to perform the spray granulation treatment on the mixed slurry.

[0008] In an exemplary embodiment of the present disclosure, the composite powder particles are placed in an oxygen-containing atmosphere and calcined to obtain ultrafine nano molybdenum trioxide, including: a calcination temperature of 500 to 700° C. and a calcination time of 1 to 2 hours.

[0009] In an exemplary embodiment of the present disclosure, the reduction temperature of the first-stage reduction treatment is 480-700° C., the heating rate is less than or equal to 10° C. / min, and the reduction time is 1-2 hours.

[0010] In an exemplary embodiment of the present disclosure, the reducing atmosphere of the second-stage reduction treatment is selected from at least one of carbon monoxide, hydrogen, and a hydrogen-argon mixed gas.

[0011] In an exemplary embodiment of the present disclosure, the reduction temperature of the second-stage reduction treatment is 700-900° C., the heating rate is less than or equal to 10° C. / min, and the reaction time is 1-3 hours.

[0012] In an exemplary embodiment of the present disclosure, the pore-forming agent is selected from at least one of polyvinyl alcohol, polyethylene glycol, and tartaric acid.

[0013] In an exemplary embodiment of the present disclosure, the mass of the pore former is 2% to 5% of the mass of the ammonium molybdate.

[0014] In an exemplary embodiment of the present disclosure, when ammonium molybdate and a pore-forming agent are dissolved in ultrapure water, the total amount of the ammonium molybdate and the pore-forming agent in the solid-liquid mixture is 40% to 80% by mass.

[0015] According to one aspect of the present disclosure, a molybdenum powder is provided, which is prepared by any one of the above methods.

[0016] In the technical solution provided in the embodiment of the present disclosure, ammonium molybdate is used as a precursor, and a mixed slurry is prepared by adding a pore-forming agent (which can also be used as a binder). The selection of the pore-forming agent and the combination of the spray granulation process can effectively achieve uniform mixing of ammonium molybdate and the pore-forming agent, increase their contact area, and realize the regulation of the nucleation and growth process of molybdenum trioxide in the subsequent roasting process. The addition of the pore-forming agent can effectively inhibit the abnormal growth of molybdenum trioxide, adjust the surface structure of molybdenum trioxide, improve its reaction activity, reduce the Gibbs free energy required for the reduction process, reduce the reduction temperature, and promote the reduction process. At the same time, it also avoids the abnormal growth of molybdenum dioxide at a higher reduction temperature, provides conditions for chemical vapor migration in the hydrogen reduction process, and obtains ultrafine molybdenum dioxide with uniform size and good dispersibility. Through further reduction, ultrafine nano molybdenum powder with good dispersibility, regular morphology and uniform size can be obtained.

[0017] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings herein are incorporated into the specification and constitute a part of the specification, illustrate embodiments consistent with the present disclosure, and together with the specification are used to explain the principles of the present disclosure. Obviously, the accompanying drawings described below are only some embodiments of the present disclosure, and for ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without creative work.

[0019] Figure 1 A flow chart of preparing molybdenum powder based on a spray granulation precursor according to an embodiment of the present disclosure is schematically shown.

[0020] Figure 2 A scanning electron microscope image (SEM image) of the ultrafine molybdenum dioxide powder obtained in step 4 of the preparation process of Example 1 of the present embodiment is schematically shown.

[0021] Figure 3 The SEM image of molybdenum powder prepared by the preparation method of Example 1 according to an embodiment of the present disclosure is schematically shown. DETAILED DESCRIPTION

[0022] The following is an explanation of the implementation of the present disclosure by means of specific embodiments. Those skilled in the art can easily understand other advantages and effects of the present disclosure from the contents disclosed in this specification.

[0023] It should be noted that the process equipment or devices not specifically specified in the following embodiments are all conventional equipment or devices in the art.

[0024] In addition, it should be understood that one or more method steps mentioned in the present disclosure do not exclude the existence of other method steps before or after the combination step or the insertion of other method steps between these explicitly mentioned steps, unless otherwise specified; it should also be understood that the combination connection relationship between one or more devices / apparatuses mentioned in the present disclosure does not exclude the existence of other devices / apparatuses before or after the combination device / apparatus or the insertion of other devices / apparatuses between these explicitly mentioned two devices / apparatuses, unless otherwise specified. Moreover, unless otherwise specified, the numbering of each method step is only a convenient tool for identifying each method step, and is not intended to limit the order of arrangement of each method step or to limit the scope of the present invention. Changes or adjustments in their relative relationships, without substantial changes in the technical content, should also be regarded as the scope of the present disclosure.

[0025] During the implementation process, it was found that the method of obtaining molybdenum trioxide by high-temperature calcination of ammonium molybdate and then preparing molybdenum dioxide and molybdenum powder through a one-stage or two-stage hydrogen reduction process has low cost and simple process, but the obtained molybdenum powder is also limited in its application in high-end manufacturing due to its coarse grains, poor dispersibility and uneven particle size.

[0026] In view of this, considering that ultrafine molybdenum trioxide (MoO3) material with good dispersibility, controllable morphology, uniform particle size and high porosity is crucial for the final preparation of molybdenum dioxide (MoO2) and molybdenum powder (Mo) with controllable particle size, good dispersibility and high porosity, the present disclosed embodiment provides a method for preparing ultrafine nano molybdenum powder based on a spray granulation precursor.

[0027] It should be noted that the molybdenum powder prepared by the method for preparing molybdenum powder in the embodiment of the present disclosure can be applied to the semiconductor field, 5G communication field, etc. Of course, the molybdenum powder prepared by the embodiment of the present disclosure can also be applied to other application fields requiring molybdenum processed products, without limitation.

[0028] Figure 1 A flow chart of preparing molybdenum powder based on a spray granulation precursor is shown, which may include:

[0029] In step S110, ammonium molybdate and a pore-forming agent are dissolved in ultrapure water at room temperature to obtain a mixed slurry.

[0030] In step S120, the mixed slurry is subjected to spray granulation treatment to obtain composite powder particles containing a pore-forming agent and ammonium molybdate.

[0031] In step S130, the composite powder particles are placed in an oxygen-containing atmosphere and calcined to obtain ultrafine nano molybdenum trioxide.

[0032] In step S140, ultrafine nano molybdenum trioxide is placed in a hydrogen atmosphere for a reduction treatment to obtain ultrafine molybdenum dioxide powder.

[0033] In step S150, ultrafine molybdenum dioxide powder is subjected to a two-stage reduction treatment to obtain ultrafine molybdenum powder, wherein the reduction conditions of the first-stage reduction treatment and the second-stage reduction treatment are different.

[0034] Next, the method for preparing molybdenum powder in the embodiment of the present disclosure is specifically described.

[0035] In step S110, ammonium molybdate and a pore-forming agent are dissolved in ultrapure water at room temperature to obtain a mixed slurry.

[0036] In the embodiment of the present disclosure, the pore former also acts as a binder, and optionally, the pore former is selected from at least one of polyvinyl alcohol (PVA), polyethylene glycol (PEG), and tartaric acid. Optionally, the mass of the pore former is 2% to 5% of the mass of ammonium molybdate.

[0037] Optionally, when ammonium molybdate and the pore-forming agent are dissolved in ultrapure water, the total amount of ammonium molybdate and the pore-forming agent in the solid-liquid mixture is 40% to 80% by mass.

[0038] By controlling the concentration of ammonium molybdate slurry, the nucleation sites of subsequent reactions can be regulated, thereby regulating the particle size of molybdenum trioxide, avoiding excessive concentration leading to large particle size agglomeration or too low concentration affecting the reaction efficiency. Mixing ammonium molybdate with a pore-forming agent and roasting it can prepare molybdenum trioxide with higher defects, increase the activity of molybdenum trioxide, and reduce the subsequent reduction temperature, which is beneficial to improving the reaction efficiency. The lower reduction temperature can inhibit the abnormal growth of grains. Therefore, the embodiment of the present disclosure can regulate the nucleation and growth process of molybdenum trioxide by regulating the ratio of pore-forming agent to ammonium molybdate, thereby controlling its particle size, morphology and dispersibility.

[0039] Among them, ultrapure water, also known as UP water, refers to water with a resistivity of 18MΩ*cm (25℃). In addition to water molecules, ultrapure water contains almost no impurities, and does not contain bacteria, viruses, organic matter such as chlorinated dioxins, nor does it contain trace minerals required by the human body, that is, water from which almost all atoms except oxygen and hydrogen have been removed. Ultrapure water can be used in the preparation process of ultrapure materials (such as semiconductor component materials, nano-fine ceramic materials, etc.) using distillation, deionization, reverse osmosis technology or other appropriate supercritical fine technology.

[0040] In step S120, the mixed slurry is subjected to spray granulation treatment to obtain composite powder particles containing a pore-forming agent and ammonium molybdate.

[0041] In the embodiment of the present disclosure, the spray granulation process refers to a granulation method in which a slurry or solution is sprayed into a granulation tower, and the slurry or solution is dried and agglomerated under the action of the spray hot air, thereby obtaining spherical granules, and the obtained granules have good ball precision and uniform particles. Among them, the temperature of the spray granulation process in the embodiment of the present disclosure is 100 to 200°C. Optionally, a spray dryer can be used to spray granulate the mixed slurry, and of course other types of spray granulation equipment can also be selected according to actual needs.

[0042] By using ammonium molybdate as a precursor and adding a pore-forming agent to prepare a mixed slurry, the selection of the pore-forming agent and the spray granulation process can effectively achieve uniform mixing of ammonium molybdate and the pore-forming agent, construct a special nano-composite structure precursor in which the pore-forming agent uniformly coats the ammonium molybdate, increase its contact area, and achieve regulation of the nucleation and growth process of molybdenum trioxide in the subsequent calcination process, and can avoid the problem of particle agglomeration caused by uneven mixing.

[0043] In step S130, the composite powder particles are placed in an oxygen-containing atmosphere and calcined to obtain ultrafine nano molybdenum trioxide.

[0044] In the embodiment of the present disclosure, the roasting temperature is 500-700° C. and the roasting time is 1-2 hours to ensure that ammonium molybdate is completely converted into molybdenum trioxide. The roasting furnace can be selected according to actual needs in the embodiment of the present disclosure, and there is no special limitation on this.

[0045] Optionally, the firing atmosphere is air or oxygen.

[0046] In step S140, ultrafine nano molybdenum trioxide is placed in a hydrogen atmosphere for a reduction treatment to obtain ultrafine molybdenum dioxide powder.

[0047] In the embodiment disclosed herein, the reduction temperature of the first reduction treatment is 480-700°C, the heating rate is less than or equal to 10°C / min, and the reduction time is 1-2h. By regulating the hydrogen reduction temperature field and the air flow field, the Mo4O 11 And the chemical vapor transport and deposition process of MoO2, to obtain ultrafine nano molybdenum dioxide materials with regular morphology and uniform size. The embodiment of the present disclosure can flexibly adjust the gas flow field of hydrogen reduction according to needs to ensure that the ultrafine nano molybdenum dioxide materials that meet the above results are obtained.

[0048] In step S150, ultrafine molybdenum dioxide powder is subjected to a two-stage reduction treatment to obtain ultrafine molybdenum powder, wherein the reduction conditions of the first-stage reduction treatment and the second-stage reduction treatment are different.

[0049] In the embodiment of the present disclosure, optionally, the reducing atmosphere of the second stage reduction treatment is selected from at least one of carbon monoxide, hydrogen, and a hydrogen-argon mixture. Optionally, the reduction temperature of the second stage reduction treatment is 700-900°C, the heating rate is less than or equal to 10°C / min, and the reaction time is 1-3h.

[0050] Among them, by selecting a reducing atmosphere, the molybdenum dioxide is further reduced and deoxidized, and the concentration of water vapor in the reaction process can be controlled to avoid gas phase dissolution and abnormal coarsening during the nucleation and growth of the molybdenum powder, thereby achieving effective control of the particle size, morphology and dispersibility of the molybdenum powder and obtaining highly dispersed ultrafine nano molybdenum powder.

[0051] Furthermore, the present disclosure also provides a molybdenum powder, which is prepared by the method for preparing molybdenum powder of the above exemplary embodiment. For details, please refer to the above embodiment, which will not be described in detail here.

[0052] In the technical solution provided in the embodiment of the present disclosure, on the one hand, compared with the shortcomings of poor particle size uniformity, difficult to control morphology, poor dispersibility, etc. of molybdenum trioxide prepared by the traditional roasting process, the embodiment of the present disclosure uniformly mixes ammonium molybdate with a pore-forming agent through a spray granulation process, constructs a special nano-composite structure precursor in which the pore-forming agent uniformly coats ammonium molybdate, increases its contact area, improves reaction efficiency, and can avoid the problem of particle agglomeration caused by uneven mixing. At the same time, the surface structure of molybdenum trioxide is regulated by the pore-forming agent to enhance the reaction activity, providing a basis for subsequent reduction and gas phase transport deposition. On the other hand, by roasting the composite powder particles obtained by spray granulation, the obtained nano molybdenum trioxide can have a higher porosity and higher activity, thereby ensuring more chemical vapor migration efficiency during its reduction process, and the prepared MoO2 has a regular morphology, a small particle size, good uniformity, and high dispersibility. Due to the higher reaction activity, the energy barrier formed by molybdenum powder in the subsequent reduction process is reduced, providing a basis for obtaining molybdenum powder with uniform particle size and high dispersion. On the other hand, the water vapor concentration in the byproduct can be effectively controlled by regulating the airflow field during the molybdenum dioxide reduction process, thereby achieving effective control of the dispersibility, particle size, and morphology of the molybdenum powder. In addition, the raw materials used in the preparation method of the disclosed embodiment are widely available, low in cost, easy to promote, and have high industrial application prospects.

[0053] The method for preparing molybdenum powder disclosed in the present invention is specifically described below through specific examples.

[0054] Example 1

[0055] The method for preparing molybdenum powder based on spray granulation precursor comprises the following steps:

[0056] Step 1: Add ammonium molybdate and pore-forming agent (PVA) into 500 mL of ultrapure water and heat and stir on a magnetic stirrer until completely dissolved to obtain a transparent mixed slurry, wherein the mass of the pore-forming agent PVA is 3% of the mass of ammonium molybdate.

[0057] Step 2: Place the mixed slurry obtained in step 1 in a spray dryer and spray granulate at 150° C. to obtain composite powder particles in which the pore-forming agent uniformly coats ammonium molybdate.

[0058] Step 3: calcining the composite powder particles obtained in step 2 in an air atmosphere to obtain ultrafine molybdenum trioxide with high porosity, high dispersion and good particle size uniformity, and the calcination temperature is 560°C.

[0059] Step 4: The ultrafine molybdenum trioxide in step 3 is subjected to hydrogen reduction treatment at 480-650° C., with a heating rate of 10° C. / min and a treatment time of 2 h to obtain ultrafine molybdenum dioxide powder.

[0060] Step 5: Place the ultrafine molybdenum dioxide obtained in step 4 in an atmosphere reduction furnace at 700-900° C. for further reduction and deoxidation, using carbon monoxide as the reducing gas, a heating rate of 10° C. / min, and a treatment time of 1 h to obtain ultrafine nano molybdenum powder.

[0061] Example 2

[0062] The method for preparing molybdenum powder based on spray granulation precursor comprises the following steps:

[0063] Step 1: Add ammonium molybdate and pore-forming agent (PEG) into 500 mL ultrapure water and heat and stir on a magnetic stirrer until completely dissolved to obtain a transparent mixed slurry. The mass of the pore-forming agent PEG is 2% of the mass of the ammonium molybdate.

[0064] Step 2: Place the mixed slurry obtained in step 1 in a spray dryer and spray granulate at 120° C. to obtain composite powder particles in which the pore-forming agent uniformly coats ammonium molybdate.

[0065] Step 3: calcining the composite powder particles obtained in step 2 in an air atmosphere to obtain ultrafine molybdenum trioxide at a calcination temperature of 600°C.

[0066] Step 4: The ultrafine molybdenum trioxide in step 3 is subjected to hydrogen reduction treatment at 500-700° C., with a heating rate of 10° C. / min and a treatment time of 2 h to obtain ultrafine molybdenum dioxide powder.

[0067] Step 5: Place the ultrafine molybdenum dioxide obtained in step 4 in an atmosphere reduction furnace at 700-800° C. for further reduction and deoxidation, using hydrogen as the reducing gas, a heating rate of 10° C. / min, and a treatment time of 2 h to obtain ultrafine nano molybdenum powder.

[0068] Example 3

[0069] The method for preparing molybdenum powder based on spray granulation precursor comprises the following steps:

[0070] Step 1: Add ammonium molybdate and tartaric acid into 500 mL of ultrapure water and place on a magnetic stirrer and heat and stir until completely dissolved to obtain a transparent mixed slurry. The mass of the pore-forming agent tartaric acid is 5% of the mass of the ammonium molybdate.

[0071] Step 2: Place the mixed slurry obtained in step 1 in a spray dryer and spray granulate at 150° C. to obtain composite powder particles in which the pore-forming agent uniformly coats ammonium molybdate.

[0072] Step 3: calcining the composite powder particles obtained in step 2 in an air atmosphere to obtain ultrafine molybdenum trioxide at a calcination temperature of 500°C.

[0073] Step 4: The ultrafine molybdenum trioxide in step 3 is subjected to hydrogen reduction treatment at 550-650° C., with a heating rate of 10° C. / min and a treatment time of 3 h to obtain ultrafine molybdenum dioxide powder.

[0074] Step 5: Place the ultrafine molybdenum dioxide obtained in step 4 in an atmosphere reduction furnace at 800-900°C for further reduction and deoxidation. The reducing gas used is a hydrogen-argon mixture, in which argon accounts for 5%. The heating rate is 20°C / min and the treatment time is 3h to obtain ultrafine nano molybdenum powder.

[0075] After the molybdenum powder was prepared by the preparation method of Examples 1 to 3, the particle size and particle distribution of the molybdenum dioxide powder and the molybdenum powder in the preparation process were analyzed using a scanning electron microscope.

[0076] like Figure 2 The SEM image (SEM image) of the ultrafine molybdenum dioxide powder obtained in step 4 of the preparation process of Example 1 is shown. Figure 2 As shown, the molybdenum dioxide powder has uniform particle size distribution, good dispersibility, and a blocky, non-oriented morphology. Based on this, it is beneficial to obtain ultrafine molybdenum powder with good dispersibility and uniform particle size distribution by performing a two-stage hydrogen reduction treatment on molybdenum dioxide.

[0077] like Figure 3 Shown is a SEM image of the molybdenum powder prepared by the preparation method of Example 1, as shown in Figure 3 As shown, the obtained nano-molybdenum powder has regular morphology, good dispersibility, high porosity and uniform size.

[0078] From the above, it can be seen that the technical solution of the embodiment of the present disclosure uses ammonium molybdate as a precursor and adopts the method of adding a pore-forming agent (which can also be used as a binder) to prepare a mixed slurry. The selection of the pore-forming agent and the combination of the spray granulation process can effectively achieve uniform mixing of ammonium molybdate and the pore-forming agent, increase their contact area, and realize the regulation of the nucleation and growth process of molybdenum trioxide in the subsequent roasting process. The addition of the pore-forming agent can effectively inhibit the abnormal growth of molybdenum trioxide, adjust the surface structure of molybdenum trioxide, improve its reaction activity, reduce the Gibbs free energy required for the reduction process, reduce the reduction temperature, and promote the reduction process. At the same time, it also avoids the abnormal growth of molybdenum dioxide at a higher reduction temperature, provides conditions for chemical vapor migration in the hydrogen reduction process, and obtains ultrafine molybdenum dioxide with uniform size and good dispersibility. By further reduction, ultrafine nano molybdenum powder with good dispersibility, regular morphology and uniform size can be obtained.

[0079] It should be noted that the above embodiments are only illustrative of the principles and effects of the present disclosure, and are not intended to limit the present disclosure. Anyone familiar with the technology may modify or change the above embodiments without violating the spirit and scope of the present disclosure. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed in the present disclosure should still be covered by the claims of the present disclosure.

Claims

1. A method for preparing molybdenum powder based on a spray granulation precursor, characterized in that: include: Dissolving ammonium molybdate and a pore-forming agent in ultrapure water at room temperature to obtain a mixed slurry; The mixed slurry is subjected to a spray granulation treatment to obtain composite powder particles containing a pore-forming agent and ammonium molybdate; The composite powder particles are placed in an oxygen-containing atmosphere and calcined to obtain ultrafine nano-molybdenum trioxide; Placing the ultrafine nano molybdenum trioxide in a hydrogen atmosphere for a reduction treatment to obtain ultrafine molybdenum dioxide powder; The ultrafine molybdenum dioxide powder is subjected to a two-stage reduction treatment to obtain ultrafine molybdenum powder, wherein the reduction conditions of the one-stage reduction treatment and the two-stage reduction treatment are different.

2. The method according to claim 1, characterized in that The temperature of spray granulation treatment is 100-200°C; Wherein, a spray dryer is used to perform spray granulation treatment on the mixed slurry.

3. The method according to claim 1, characterized in that The step of placing the composite powder particles in an oxygen-containing atmosphere and calcining them to obtain ultrafine nano molybdenum trioxide comprises: The calcination temperature is 500-700°C, and the calcination time is 1-2h.

4. The method according to claim 1, characterized in that: The reduction temperature of the one-stage reduction treatment is 480-700° C., the heating rate is less than or equal to 10° C. / min, and the reduction time is 1-2 hours.

5. The method according to claim 1, characterized in that The reducing atmosphere of the second-stage reduction treatment is selected from at least one of carbon monoxide, hydrogen, and a hydrogen-argon mixed gas.

6. The method according to claim 5, characterized in that The reduction temperature of the two-stage reduction treatment is 700-900° C., the heating rate is less than or equal to 10° C. / min, and the reaction time is 1-3 hours.

7. The method according to claim 1, characterized in that The pore-forming agent is selected from at least one of polyvinyl alcohol, polyethylene glycol and tartaric acid.

8. The method according to claim 1, characterized in that The mass of the pore-forming agent is 2% to 5% of the mass of ammonium molybdate.

9. The method according to claim 8, characterized in that When ammonium molybdate and the pore-forming agent are dissolved in ultrapure water, the total amount of the ammonium molybdate and the pore-forming agent in the solid-liquid mixture is 40% to 80% by mass.

10. A molybdenum powder, characterized in that: The molybdenum powder is prepared by the method according to any one of claims 1 to 9.

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