CN115365511A - Gas phase reduction and collection device and method for narrow-distribution ultrafine molybdenum powder - Google Patents
Gas phase reduction and collection device and method for narrow-distribution ultrafine molybdenum powder Download PDFInfo
- Publication number
- CN115365511A CN115365511A CN202211087137.6A CN202211087137A CN115365511A CN 115365511 A CN115365511 A CN 115365511A CN 202211087137 A CN202211087137 A CN 202211087137A CN 115365511 A CN115365511 A CN 115365511A
- Authority
- CN
- China
- Prior art keywords
- molybdenum
- molybdenum powder
- hydrogen
- gas phase
- reduction
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F9/00—Making metallic powder or suspensions thereof
- B22F9/16—Making metallic powder or suspensions thereof using chemical processes
- B22F9/18—Making metallic powder or suspensions thereof using chemical processes with reduction of metal compounds
- B22F9/28—Making metallic powder or suspensions thereof using chemical processes with reduction of metal compounds starting from gaseous metal compounds
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
- B22F1/05—Metallic powder characterised by the size or surface area of the particles
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
- B22F1/14—Treatment of metallic powder
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
Abstract
A gas phase reduction and collection device and a gas phase reduction and collection method for narrow-distribution ultrafine molybdenum powder. The invention utilizes MoO 3 The MoO is realized by heating at about 900 deg.C with highest sublimation efficiency 3 And (4) sublimating. MoO control through temperature and pressure regulation of sublimation process 3 Sublimation gas amount and molecular weight, and timely blowing-off to ensure MoO 3 And (4) stably sublimating. By the method of arranging the microchannel reactor, instantaneous uniform mixing and completely consistent reaction conditions of the gas-phase molybdenum source and hydrogen in time and space are realized, molybdenum trioxide is completely reduced in a very short time, and a narrow distribution interval of the granularity of the superfine molybdenum powder is ensured. Anhydrous alcohol is used as cooling and collecting liquid, when the product is introduced into alcohol to generate bubbles, the bubbles are crushed by a stirring device with a sawtooth-shaped impeller to sharply reduce the size of the bubbles,the contact area of the bubbles containing the molybdenum powder particles and the alcohol is enlarged, the rapid cooling and collection of the ultrafine molybdenum powder are realized, and the agglomeration phenomenon of the ultrafine molybdenum powder is reduced.
Description
Technical Field
The invention relates to a molybdenum powder processing device and method, in particular to a gas phase reduction and collection device and method for narrow-distribution ultrafine molybdenum powder.
Background
The refractory metal molybdenum has a melting point as high as 2610 ℃, not only has excellent heat conduction, electric conduction and corrosion resistance, but also has low thermal expansion coefficient, higher hardness and good high-temperature strength, thereby having wide application in the fields of electronic industry, aerospace industry, energy industry and the like. The ultra-fine molybdenum powder with the grain diameter less than 1.5 mu m has more excellent mechanical, electrical, magnetic, thermal, optical and chemical (including catalyst) performances. Ultrafine powders are commonly used in the production of powder metallurgy and cermet compacts, alloys, specialty ceramics and electrical components. They are excellent fillers, abrasives, pigments, catalysts and can also be used in corrosion-, wear-and heat-resistant coatings. Adding 3-5% of superfine molybdenum powder into molybdenum powder with common granularity for compression and sintering, the sintering temperature can be greatly reduced, and molybdenum alloy products with high density can be obtained. The molybdenum powder granularity has great influence on the chemical properties of the molybdenum powder, and researches show that the molybdenum powder with different granularities has different sintering activities and catalytic activities. Therefore, obtaining narrow distribution characteristics is one of the most important indexes of ultra-fine molybdenum powder.
The existing preparation of ultrafine molybdenum powder is mainly divided into a thermal decomposition method and a reduction method. The thermal decomposition method is to react chlorine with molybdenite to prepare MoCl 6 Then heating at high temperature to decompose MoCl 6 Preparing superfine molybdenum powder; the reduction process is further divided into C reduction process and H 2 A reduction method. The carbon reduction method is to mix C and MoO 3 High-energy ball milling is carried out, and MoO is prepared through low-temperature section 2 Then continuously reducing at a high temperature section to obtain superfine molybdenum powder; h 2 The reduction process is carried out with H 2 As a reducing agent, reducing industrial molybdenum oxide in a closed high-temperature environment,Preparing ultrafine molybdenum powder from molybdenum carbonyl or molybdenum chloride. In addition, ultrafine molybdenum powder can also be obtained by reducing ultrafine precursors such as sublimed molybdenum trioxide, ultrafine ammonium octamolybdate and other raw materials.
Currently, such techniques have some drawbacks and limitations, in particular:
1) The thermal decomposition method takes molybdenum pentachloride as a raw material and prepares the ultrafine molybdenum powder by high-temperature heating decomposition. However, chlorine gas is used in the preparation and purification processes of molybdenum pentachloride, and the pollution of chlorine gas to the atmosphere and the harm to people, livestock and plants should be paid attention to, so that the molybdenum powder prepared by the method is not suitable for industrial large-scale production. The molybdenum chloride thermal decomposition method has simple preparation process, can produce molybdenum powder with higher purity, and has smaller granularity; however, the thermal decomposition method of molybdenum chloride requires high demand for the raw materials used, and there are problems such as discharge of waste gas and recovery treatment when it is used.
The specific experimental procedures can be summarized as follows: using molybdenite concentrate as raw material, chlorinating it with chlorine gas at 270 deg.C to produce MoCl 5 The reaction formula is as follows:
2MoS 2 +5Cl 2 ＝2MoCl 5 +2S 2 (1)
then, pure molybdenum powder can be obtained through heating decomposition, and the reaction formula is as follows:
2MoCl 5 ＝2Mo+5Cl 2 (2)
2) C reduction of MoO 3 In the experimental process, firstly, moO 3 And C, the uniformity of mixing affects the reactant contact area, the nucleation rate of the product, the diffusion rate of the reactant through the product phase and thus directly affects the reaction rate and progress; further, it is very difficult to control the amount of carbon added, and excessive addition tends to introduce impurities, while insufficient addition results in insufficient reduction. In addition, carbon reduction produces CO 2 Gas emissions, which do not meet the national "double carbon" target, will also be limited in the future.
Saghafi et al 3 Mixing with C in high-energy ball mill, and preparing MoO at low temperature 2 Then, thenThen continuously reducing at a high temperature section to prepare the ultrafine molybdenum powder with the average grain size of 45 nm. The reactions mainly occur as shown in formulas (3) and (4).
600℃ 2MoO 3 +C＝2MoO+CO 2 (3)
1050℃ MoO 2 +2C＝Mo+2CO (4)
However, it is difficult to precisely control the amount of carbon added in the molybdenum powder prepared by carbothermic reduction, molybdenum carbide is easily generated in the product when the amount of carbon added is excessive, and the molybdenum oxide cannot be completely reduced into molybdenum powder when the amount of carbon added is insufficient.
3) The carbonyl molybdenum and the molybdenum fluoride required by the chemical vapor reduction method are ideal methods for preparing the narrow-distribution ultrafine molybdenum powder. However, since the raw materials are very expensive and the molybdenum fluoride generates HF during use, its strong corrosiveness and toxicity impose extremely strict requirements on equipment and operators. Similarly, the preparation of the molybdenum carbonyl needs to be carried out in a CO environment, the requirement is strict, the requirement on the reaction environment is extremely high, and the industrial production is difficult to realize.
As early as 60 years in the world, the gas-phase reduction technology was studied in Soviet Union to prepare tungsten-molybdenum metal powder, and Ultramet in the United states carries out a great deal of technical development and application. However, the existing molybdenum gas phase reduction technology mainly uses molybdenum chloride, molybdenum fluoride and molybdenum carbonyl as metal gas phases, the price of the gas phase is very high, the molybdenum chloride reacts with hydrogen to generate HCl gas, and the molybdenum fluoride is firstly heated and volatilized into gas at low temperature in the using process and then reacts with H to generate the HCl gas 2 The mixture is mixed to carry out gas phase reaction to produce Mo and HF gas. At present, the recycling of HF gas has been successfully solved. However, the strong corrosiveness and toxicity of both hydrofluoric acid and HF itself place stringent requirements on equipment and personnel handling. Similarly, the preparation process of molybdenum carbonyl needs to be carried out in a CO environment, and the requirement is harsh, and although nickel carbonyl has been studied successfully and related to iron carbonyl and molybdenum carbonyl, the strict preparation environment severely limits the popularization of the molybdenum carbonyl in the industry.
4)H 2 Reduction of MoO 3 The method is a traditional molybdenum powder preparation method, and comprises first-stage reduction and second-stage reductionAnd a three-stage reduction method, the reaction process of the one-stage reduction is difficult to control, and the obtained molybdenum powder has coarse granularity and poor quality; the process which has the greatest influence on the quality of the molybdenum powder in the two-stage reduction is the two-stage reduction of the molybdenum powder, namely MoO 2 The coarse molybdenum powder reduced from the second stage is sieved and mixed uniformly to obtain finished molybdenum powder with the granularity of 3-4 mu m; the three-stage principle is mainly used for preparing high-purity molybdenum powder and molybdenum powder with low oxygen content and large particle size. If ultra-fine molybdenum powder is to be prepared by a hydrogen reduction method, ultra-fine precursors such as sublimed molybdenum trioxide, fine-grained ammonium octamolybdate, molybdic acid and the like must be used.
There are mainly 3 traditional process flows for hydrogen reduction of molybdenum oxide: moO 3 One-stage reduction, moO 3 Two stage reduction and MoO 3 And (4) three-stage reduction. MoO 3 The one-stage reduction process is simple, and intermediate steps such as screening and batching are not required in the reduction process, so that the MoO can be obtained 3 Reducing the molybdenum powder in one step. But the reaction process of one-stage reduction is difficult to control, and the obtained molybdenum powder has low purity, coarse granularity and poor quality. The two-stage reduction process is to firstly perform MoO 3 Reduction to MoO 2 Then the mixture is put into the furnace again and heated to a higher temperature zone to be reduced into molybdenum powder. The molybdenum powder prepared by the two-stage reduction process has good quality and fine granularity (3-4 mu m). MoO 3 Two-stage reduction is the most commonly used process in industry, for example, the gold heaping city molybdenum industry gmbh invented a method for preparing molybdenum powder by two-stage reduction using molybdenum trioxide as raw material: putting the ball-milled molybdenum trioxide powder in a hydrogen atmosphere, and in the first stage, moO 3 Reduction to MoO 2 The second stage is to mix MoO 2 And continuously reducing the molybdenum powder into rough Mo powder, and finally sieving the rough Mo powder and placing the sieved rough Mo powder into a mixer to be uniformly mixed to obtain the finished molybdenum powder. In the process of preparing molybdenum powder by hydrogen reduction, the process which has the greatest influence on the quality of the molybdenum powder is two-stage reduction of the molybdenum powder, namely MoO 2 Reduction to molybdenum powder. MoO 3 The three-stage reduction method is to perform high-temperature oxygen reduction again under the condition that the oxygen content of the molybdenum powder obtained after two times of reduction is still high. The process is mainly used for preparing molybdenum powder with special purpose, such as high-purity molybdenum powder with extremely low oxygen content and molybdenum powder with large particle size of more than 10 μm。
The nanometer molybdenum powder is successfully prepared by mixing and reducing a gas-phase sublimate generated by sublimating molybdenum oxide and hydrogen gas by utilizing Beijing science and technology university Zhanghua (patent number CN 110227826A). However, the superfine molybdenum powder has a simple structure, and the difference between the micro-area thermal field and the atmosphere is large, so that the uniform particle size distribution is difficult to ensure.
Particularly, the superfine molybdenum powder reduction technology has larger change due to the condition factors (temperature, gas concentration and the like) of the reaction micro-area in the reduction process. For example, in conventional reactors, the reactant micromixing rate is less than the chemical reaction rate, and therefore the reaction process is affected by mass transfer, resulting in inconsistent chemical reaction rates throughout the reactor and localized supersaturation differences. Meanwhile, the traditional reactor has thick gas flow boundary layer, low temperature conduction efficiency and inconsistent local temperature with the whole body. The nano particles prepared under the conditions have large particle size, wide distribution and high agglomeration probability among particles, so that the product quality is greatly reduced, and the superfine molybdenum powder is produced with wider particle size distribution, thereby greatly reducing the product quality. This has a very severe effect on the surface activity of the ultra-fine molybdenum powder, directly resulting in a significant difference in its later use properties.
Disclosure of Invention
The invention aims to provide a gas phase reduction and collection device and a gas phase reduction and collection method for narrow-distribution ultrafine molybdenum powder, which can realize the integrated molding of industrial molybdenum trioxide to ultrafine molybdenum powder with uniform particle size, greatly reduce the equipment investment and operation cost, reduce the energy consumption and pollution emission of the preparation of the ultrafine molybdenum powder, and realize the narrow-distribution-high-efficiency-low-cost-green preparation of the ultrafine molybdenum powder.
In order to achieve the purpose, the device comprises a molybdenum source stable sublimation area, a very fast reduction area and a cooling and collecting area which are communicated in sequence;
the molybdenum source stable sublimation area comprises a molybdenum trioxide evaporation tank, the inlet of the molybdenum source stable sublimation area is connected with the argon pressure maintaining tank, and the outlet of the molybdenum source stable sublimation area is connected with the top-speed reduction area and is used for evaporating molybdenum trioxide;
the ultra-fast reduction zone is a microchannel reactor with an inlet end connected with an outlet of the molybdenum trioxide evaporation tank and an outlet end connected with a cooling and collecting zone, and the microchannel reactor consists of a tubular hydrogen distribution bin, a central support rod and a microchannel. The tubular hydrogen distribution bin is of a concentric multilayer structure, a plurality of micro-channels which are arranged along the circumference of a concentric circle are distributed between each layer of the tubular hydrogen distribution bin, a plurality of small holes are uniformly distributed on the tangent line of the inner wall of each layer of the tubular hydrogen distribution bin and the micro-channels, a plurality of small holes are uniformly distributed on the tangent line of each micro-channel and the inner side of the tubular hydrogen distribution bin, the tubular hydrogen distribution bin corresponds to the small holes on the micro-channels, and hydrogen enters the micro-channels from the tubular hydrogen distribution bin through the small holes under the pressure action. (ii) a
The cooling and collecting area comprises a cooling and collecting device and absolute ethyl alcohol arranged in the cooling and collecting area, and an outlet of the microchannel reactor extends into the absolute ethyl alcohol.
And an inlet valve and an outlet valve are respectively arranged on an inlet pipeline and an outlet pipeline of the molybdenum trioxide evaporation tank.
And a pressure detection meter is arranged on the molybdenum trioxide evaporation tank.
And a blow-off device is arranged on one side of the molybdenum trioxide evaporation tank opposite to the outlet.
The inlet of the microchannel reactor is a conical airflow buffer with an inverted conical structure.
The center of the microchannel reactor is provided with a support rod, the microchannels at the innermost layer are arranged along the circumference of the support rod, and the diameter of each microchannel is 10-1000 mu m.
And a stirring device is arranged in the cooling and collecting device.
And a hydrogen valve is arranged on a road where the hydrogen and water vapor separation and buffer tank is communicated with the tubular hydrogen distribution bin.
The cooling and collecting device is also connected with a recovery area, and the recovery area comprises a gas, water and ethanol separator and a hydrogen and argon separator which are respectively connected with an argon pressure maintaining tank, a hydrogen and water vapor separation and buffer tank.
The gas phase reduction and collection method of the narrow-distribution ultrafine molybdenum powder comprises the following steps:
1) Stable sublimation of gaseous molybdenum source
Mixing high-purity MoO 3 Placing in a molybdenum trioxide evaporation tank, opening an argon pressure maintaining tank to replace air in the molybdenum trioxide evaporation tank by vacuum exhaust and gas replacement, heating the furnace to 900 ℃ under the protection of argon, opening an outlet valve and a blow-off device when the positive pressure in the furnace is more than or equal to 50pa, and sublimed MoO 3 The gas flow is driven to enter a micro-channel reactor;
2) Gas phase mixing and rapid reduction
Meanwhile, hydrogen enters the micro-channel from the tubular hydrogen distribution bin through the micropores and is in contact with the gas-phase MoO entering from the axis of the micro-channel 3 Forming vertical cross airflow to realize instant uniform mixing and completely consistent reaction conditions of the gas phase molybdenum source and hydrogen in time and space, and generating ultrafine molybdenum powder with narrow particle size distribution through uniform mixing and very fast reduction;
3) Cooling and collecting superfine molybdenum powder
The ultra-fine molybdenum powder with narrowly distributed particle size generated by reduction flows out from the other side of the microchannel reactor under the action of gas pressure, the ultra-fine molybdenum powder is communicated to absolute ethyl alcohol of a cooling and collecting device at the outlet of the microchannel reactor through a pipeline, generated bubbles are broken through a stirring device, the contact area of the bubbles and collecting liquid, namely the absolute ethyl alcohol is increased, molybdenum powder particles are cooled and collected, and the molybdenum powder particles in the bubbles are remained in the collecting liquid; discharging the vapor and excessive hydrogen generated by gas phase reduction out of the cooling and collecting device along with bubbles, and drying the collected liquid containing molybdenum powder particles in an argon environment to obtain ultrafine molybdenum powder;
4) Recycling and utilizing
The water vapor, hydrogen and argon which are not completely reacted return to corresponding hydrogen and water vapor separation and buffer tanks and argon pressure maintaining tanks for recycling through a gas, water and ethanol separator and a hydrogen and argon separator.
The invention utilizes MoO 3 The MoO is realized by heating with the characteristic of highest sublimation efficiency at about 900 DEG C 3 And (4) sublimating. And control of MoO by temperature and pressure of sublimation process 3 Sublimation gas amount and molecular weight. Control of blown-off sublimated MoO by controlling fan speed 3 Steam, which ensures the stable evaporation of the molybdenum trioxide; the simultaneous and simultaneous mixing of the reactants is critical to achieving product consistency. The invention realizes the instant uniform mixing and completely consistent reaction conditions of the gas phase molybdenum source and the hydrogen in time and space by arranging the microchannel reactor, realizes the complete reduction of the molybdenum trioxide in a very short time, and ensures the narrow distribution interval of the granularity of the superfine molybdenum powder. The traditional cooling process for preparing the ultrafine molybdenum powder by gas-phase reduction is furnace cooling, and because the particle size is extremely small, the agglomeration phenomenon is easy to occur, so that the particle size is not uniform. According to the invention, absolute alcohol is used as cooling and collecting liquid, when the product is introduced into alcohol to generate bubbles, the bubbles are crushed by the stirring device with the sawtooth impeller, the size of the bubbles is rapidly reduced, the contact area of the bubbles containing molybdenum powder particles and the alcohol is enlarged, the rapid cooling and collection of the ultrafine molybdenum powder are realized, and the agglomeration phenomenon of the ultrafine molybdenum powder is reduced.
Drawings
Fig. 1 is a schematic view of the overall structure of the present invention.
FIG. 2 is a schematic diagram of the microchannel reactor 12 of the present invention.
Fig. 3 is a side view of fig. 2 of the present invention.
Wherein: 1. a molybdenum source stable sublimation area, a 2, a top-speed reduction area, a 3, a cooling and collecting area, a 4, a recovery area, a 5, an argon pressure maintaining tank, a 6, an inlet valve, a 7, a blow-off device, a 8, a pressure detecting meter, a 9, a molybdenum trioxide evaporating tank, a 10, molybdenum trioxide, a 11, an outlet valve, a 12, a microchannel reactor, a 13, a cooling and collecting device, a 14, a collecting object, a 15, a stirring device, a 16, a hydrogen valve, a 17, a hydrogen and water vapor steam-water separation and buffer tank, a 121, molybdenum trioxide steam, a 122, a conical airflow buffer, a 123, a tubular hydrogen distribution bin, a 124, a support rod and a 125 microchannel.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings.
Referring to fig. 1, the device of the invention comprises a molybdenum source stable sublimation area 1, a very fast reduction area 2 and a cooling and collecting area 3 which are communicated in sequence;
the molybdenum source stable sublimation area 1 comprises a molybdenum trioxide evaporation tank 9, an inlet of the molybdenum trioxide evaporation tank is connected with an argon pressure maintaining tank 5, an outlet of the molybdenum trioxide evaporation tank is connected with the rapid reduction area 2, the molybdenum trioxide evaporation tank 9 is used for evaporating molybdenum trioxide 10, an inlet valve 6 and an outlet valve 11 are respectively arranged on an inlet pipeline and an outlet pipeline of the molybdenum trioxide evaporation tank 9, a pressure detection meter 8 is arranged on the molybdenum trioxide evaporation tank 9, and a blow-off device 7 is arranged on one side, opposite to the outlet, in the molybdenum trioxide evaporation tank 9;
referring to fig. 2 and 3, the inlet end of the very fast reduction region 2 of the invention is connected with the outlet of the molybdenum trioxide evaporation tank 9, the outlet end is connected with the microchannel reactor 12 connected with the cooling and collecting region 3, the inlet of the microchannel reactor 12 is a conical airflow buffer 122 with an inverted cone-shaped structure, the rear end of the conical airflow buffer 122 is provided with a plurality of microchannels 125 with the diameter of 10-1000 μm which are arranged along the circumference of a concentric circle, the center of the microchannel reactor 12 is provided with a supporting rod 124, the microchannels 125 at the innermost layer are arranged along the circumference of the supporting rod 124, a tubular hydrogen distribution bin 123 which is communicated with the buffer tank 17 and is provided with a hydrogen valve 16 and is communicated with the hydrogen and water vapor is arranged between each layer of microchannels 125, and a plurality of communicated micropores are uniformly arranged on the tangent line of each microchannel 125 and the inner wall of the tubular hydrogen distribution bin 123;
the cooling and collecting area 3 comprises a cooling and collecting device 13 and absolute ethyl alcohol arranged in the cooling and collecting area, the outlet of the microchannel reactor 12 extends into the absolute ethyl alcohol, and a stirring device 15 is arranged in the cooling and collecting device 13;
the cooling and collecting device 13 of the invention is also connected with a recovery area 4, and the recovery area 4 comprises a gas, water and ethanol separator and a hydrogen-argon separator which are respectively connected with an argon pressure maintaining tank 5, a hydrogen-water vapor separation and buffer tank 17.
The gas phase reduction and collection method of the narrow-distribution ultrafine molybdenum powder comprises the following steps:
1) Stable sublimation of gas phase molybdenum source
Mixing high-purity MoO 3 10 is put into a molybdenum trioxide evaporation tank 9, an argon pressure maintaining tank 5 is opened to replace the air in the molybdenum trioxide evaporation tank 9 in a vacuum exhaust and gas replacement mode, the furnace temperature is raised to 900 ℃ under the protection of argon, and when the positive pressure in the furnace is more than or equal to 50pa, an outlet valve 11 is opened and blowing is carried outCentrifuge 7, sublimed MoO 3 The steam 121 enters the microchannel reactor 12 under the driving of the airflow;
2) Gas phase uniform mixing and rapid reduction
MoO from the molybdenum Source stabilization sublimation zone 1 3 Steam 121 enters the microchannel reactor 12 at the temperature of about 900 ℃, a conical airflow buffer 122 is arranged at the inlet of the microchannel reactor 12 and serves as a molybdenum trioxide steam airflow buffer area, so that the pressure and the speed of the molybdenum trioxide steam 121 entering each microchannel 125 are the same, hydrogen enters the microchannel 125 from the hydrogen and water steam separation and buffer tank 17, enters the tubular hydrogen distribution bin 123 through the micropores, and enters the gas-phase MoO from the axis of the microchannel 125 3 Forming vertical cross airflow to realize instantaneous uniform mixing and completely consistent reaction conditions of a gas phase molybdenum source and hydrogen in time and space, and generating superfine molybdenum powder with narrow particle size distribution through uniform mixing and extremely-fast reduction;
3) Cooling and collecting of ultra-fine molybdenum powder
The ultra-fine molybdenum powder with narrowly distributed particle size generated by reduction flows out from the other side of the microchannel reactor 12 under the action of gas pressure, the ultra-fine molybdenum powder is led into the absolute ethyl alcohol of the cooling and collecting device 13 at the outlet of the microchannel reactor 12 through a pipeline, generated bubbles are broken through the stirring device 15, the contact area of the bubbles and collecting liquid, namely the absolute ethyl alcohol is increased, molybdenum powder particles are cooled and collected, and the molybdenum powder particles in the bubbles are left in the collecting liquid; the vapor generated by the gas phase reduction and the excessive hydrogen are discharged out of the cooling and collecting device 13 along with the bubbles, and the collected liquid containing molybdenum powder particles is dried in the argon environment to obtain the ultra-fine molybdenum powder;
the ultrafine molybdenum powder can also be stored and transported through the organic matters with better thermal stability by means of the compatibility of alcohol and the organic matters;
4) Recycling and utilizing
The water vapor, hydrogen and argon which are not completely reacted return to the corresponding hydrogen and water vapor separation and buffer tank 17 and argon pressure maintaining tank 5 for recycling through the gas, water and ethanol separator and the hydrogen and argon separator.
According to the invention, by utilizing the principle of a microchannel reactor, the concentration of the gas-phase molybdenum oxide is uniformly supplied by uniformly distributing the sublimed molybdenum oxide through the microchannels on the cross section of the reaction zone; the hydrogen is uniformly input through the pores which are uniformly distributed in the micro-channel in the axial direction. The micro-channel reducer is uniform in overall temperature by using high-thermal-conductivity metals such as molybdenum, copper and molybdenum-copper alloys thereof.
In the traditional reactor, the reaction process is influenced by mass transfer speed to a certain extent, and the reaction is in sequence, time is not uniform, and degrees are different. Thus, the product showed a broad particle size distribution. And through the reduction of the microchannel reactor, the narrow channel shortens the transfer time and the transfer distance of reactants, has strong mass transfer characteristic, obviously enhances the molecular diffusion, has consistent reaction duration and narrow product uniformity distribution.
The molybdenum oxide realizes the uniform mixing of molecular level by gas phase and hydrogen, and has high reaction speed and low energy consumption.
Claims (10)
1. A gas phase reduction and collection device for narrow-distribution ultrafine molybdenum powder is characterized in that: comprises a molybdenum source stable sublimation area (1), a rapid reduction area (2) and a cooling and collecting area (3) which are communicated in sequence;
the molybdenum source stable sublimation area (1) comprises a molybdenum trioxide evaporation tank (9) which is connected with an argon pressure maintaining tank (5) at the inlet and connected with the top-speed reduction area (2) at the outlet and is used for evaporating molybdenum trioxide;
the rapid reduction zone (2) is a microchannel reactor (12) with an inlet end connected with an outlet of a molybdenum trioxide evaporation tank (9) and an outlet end connected with a cooling and collecting zone (3), and the microchannel reactor (12) consists of a tubular hydrogen distribution bin (123), a central support rod (124) and a microchannel (125). The tubular hydrogen distribution bin (123) is of a concentric multilayer structure, a plurality of micro-channels (125) which are arranged along the circumference of a concentric circle are distributed between each layer of the tubular hydrogen distribution bin (123), a plurality of small holes are uniformly distributed on the tangent line of the inner wall of each layer of the tubular hydrogen distribution bin (123) and the micro-channels (125), a plurality of small holes are uniformly distributed on the tangent line of the inner side of each micro-channel (125) and the tubular hydrogen distribution bin (123), the tubular hydrogen distribution bin (123) corresponds to the small holes on the micro-channels (125), and hydrogen enters the micro-channels (125) from the tubular hydrogen distribution bin (123) through the small holes under the action of pressure.
The cooling and collecting area (3) comprises a cooling and collecting device (13) and absolute ethyl alcohol arranged in the cooling and collecting area, and an outlet of the microchannel reactor (12) extends into the absolute ethyl alcohol.
2. The gas phase reduction and collection device for the narrowly distributed ultra-fine molybdenum powder as claimed in claim 1, wherein: an inlet valve (6) and an outlet valve (11) are respectively arranged on an inlet and an outlet pipeline of the molybdenum trioxide evaporation tank (9).
3. The gas phase reduction and collection device for the narrow distribution ultrafine molybdenum powder of claim 1, wherein: and a pressure detection meter (8) is arranged on the molybdenum trioxide evaporation tank (9).
4. The gas phase reduction and collection device for the narrow distribution ultrafine molybdenum powder of claim 1, wherein: and a blow-off device (7) is arranged on one side of the molybdenum trioxide evaporating pot (9) opposite to the outlet.
5. The gas phase reduction and collection device for the narrow distribution ultrafine molybdenum powder of claim 1, wherein: the inlet of the microchannel reactor (12) is a conical airflow buffer (122) with an inverted conical structure.
6. The gas phase reduction and collection device for the narrowly distributed ultra-fine molybdenum powder as claimed in claim 1, wherein: the center of the microchannel reactor (12) is provided with a support rod (124), the microchannels (125) at the innermost layer are arranged along the circumference of the support rod 124, and the diameter of the microchannels (125) is 10-1000 mu m.
7. The gas phase reduction and collection device for the narrow distribution ultrafine molybdenum powder of claim 1, wherein: and a stirring device (15) is arranged in the cooling and collecting device (13).
8. The gas phase reduction and collection device for the narrowly distributed ultra-fine molybdenum powder as claimed in claim 1, wherein: and a hydrogen valve (16) is arranged on a road where the hydrogen and water vapor separation and buffer tank (17) is communicated with the tubular hydrogen distribution bin (123).
9. The gas phase reduction and collection device for the narrowly distributed ultra-fine molybdenum powder as claimed in claim 1, wherein: the cooling and collecting device (13) is also connected with the recovery area (4), and the recovery area (4) comprises a gas, water and ethanol separator and a hydrogen-argon separator which are respectively connected with an argon pressure maintaining tank (5), a hydrogen and water vapor separation and buffer tank (17).
10. A gas phase reduction and collection method of the narrow distribution ultra-fine molybdenum powder of the apparatus of any one of claims 1 to 9, wherein:
1) Stable sublimation of gas phase molybdenum source
Mixing high-purity MoO 3 Placing in a molybdenum trioxide evaporation tank (9), opening an argon pressure maintaining tank (5) to replace air in the molybdenum trioxide evaporation tank (9) in a vacuum exhaust and gas replacement mode, raising the furnace temperature to 900 ℃ under the protection of argon, opening an outlet valve (11) and a blow-off device (7) when the positive pressure in the furnace is more than or equal to 50pa, and sublimating MoO 3 Enters a micro-channel reactor (12) under the driving of the airflow;
2) Gas phase uniform mixing and rapid reduction
Meanwhile, hydrogen enters the micro-channel (125) from the tubular hydrogen distribution bin (123) through the micropores and is in contact with the gas-phase MoO entering from the axis of the micro-channel (125) 3 Forming vertical cross airflow to realize instant uniform mixing and completely consistent reaction conditions of the gas phase molybdenum source and hydrogen in time and space, and generating ultrafine molybdenum powder with narrow particle size distribution through uniform mixing and very fast reduction;
3) Cooling and collecting of ultra-fine molybdenum powder
Ultra-fine molybdenum powder with narrowly distributed particle sizes generated by reduction flows out from the other side of the microchannel reactor (12) under the action of gas pressure, the ultra-fine molybdenum powder is communicated to absolute ethyl alcohol of a cooling and collecting device (13) through a pipeline at an outlet of the microchannel reactor (12), generated bubbles are broken through a stirring device (15), the contact area of the bubbles and collecting liquid, namely the absolute ethyl alcohol is increased, molybdenum powder particles are cooled and collected, and the molybdenum powder particles in the bubbles are left in the collecting liquid; the vapor generated by gas phase reduction and excessive hydrogen are discharged out of the cooling and collecting device (13) along with bubbles, and collected liquid containing molybdenum powder particles is dried in an argon environment to obtain ultra-fine molybdenum powder;
4) Recycle and utilize
The water vapor and hydrogen gas which are not completely reacted and argon gas return to the corresponding hydrogen gas and water vapor separation and buffer tank (17) and the argon gas pressure maintaining tank (5) for recycling through the gas, water and ethanol separator and the hydrogen and argon separator.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211087137.6A CN115365511B (en) | 2022-09-07 | 2022-09-07 | Gas-phase reduction and collection device and method for narrow-distribution superfine molybdenum powder |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211087137.6A CN115365511B (en) | 2022-09-07 | 2022-09-07 | Gas-phase reduction and collection device and method for narrow-distribution superfine molybdenum powder |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN115365511A true CN115365511A (en) | 2022-11-22 |
| CN115365511B CN115365511B (en) | 2023-06-30 |
Family
ID=84070500
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202211087137.6A Active CN115365511B (en) | 2022-09-07 | 2022-09-07 | Gas-phase reduction and collection device and method for narrow-distribution superfine molybdenum powder |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115365511B (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3062638A (en) * | 1961-05-03 | 1962-11-06 | Union Carbide Corp | Ultrafine metal powders |
| CN102632249A (en) * | 2012-03-29 | 2012-08-15 | 洛阳开拓者投资管理有限公司 | Method for preparing metal molybdenum powder |
| CN107262733A (en) * | 2017-08-02 | 2017-10-20 | 北京科技大学 | A kind of method that two-part reduction prepares ultrafine molybdenum powder |
| CN114606479A (en) * | 2022-03-11 | 2022-06-10 | 西安交通大学 | Molybdenum vapor deposition molding integrated device and method |
-
2022
- 2022-09-07 CN CN202211087137.6A patent/CN115365511B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3062638A (en) * | 1961-05-03 | 1962-11-06 | Union Carbide Corp | Ultrafine metal powders |
| CN102632249A (en) * | 2012-03-29 | 2012-08-15 | 洛阳开拓者投资管理有限公司 | Method for preparing metal molybdenum powder |
| CN107262733A (en) * | 2017-08-02 | 2017-10-20 | 北京科技大学 | A kind of method that two-part reduction prepares ultrafine molybdenum powder |
| CN114606479A (en) * | 2022-03-11 | 2022-06-10 | 西安交通大学 | Molybdenum vapor deposition molding integrated device and method |
Also Published As
| Publication number | Publication date |
|---|---|
| CN115365511B (en) | 2023-06-30 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP5442260B2 (en) | Method for producing densified molybdenum metal powder | |
| JP3541939B2 (en) | Method for producing fine and ultrafine powder and transfer arc plasma system | |
| Gürmen et al. | Synthesis of nanosized spherical cobalt powder by ultrasonic spray pyrolysis | |
| TWI619672B (en) | Device and method for making particles | |
| Liu et al. | Preparation of nanosized Mo powder by microwave plasma chemical vapor deposition method | |
| CN111940757B (en) | Device and method for continuously preparing noble metal and alloy nanoparticles thereof | |
| CN104995134B (en) | Produce carbon nano-structured method and device | |
| KR100808027B1 (en) | Fabrication method of nickel nano-powder by gas phase reaction | |
| CN111187958B (en) | Mo powder/MoO2Method for preparing nano lanthanum-molybdenum oxide alloy by doping with lanthanum ammonium molybdate powder | |
| CN108080649A (en) | A kind of method that hydrocarbon duplex reduction of low temperature prepares superfine iron powder | |
| Bodkin et al. | Centrifugal shot casting: a new atomization process for the preparation of high-purity alloy powders | |
| Rykalin | Plasma engineering in metallurgy and inorganic materials technology | |
| CN113800522A (en) | Method for preparing high-purity compact tungsten carbide-cobalt composite spherical powder material | |
| US3062638A (en) | Ultrafine metal powders | |
| Wang et al. | The processes for fabricating nanopowders | |
| Zeng et al. | Effect of central gas velocity and plasma power on the spheroidizing copper powders of radio frequency plasma | |
| Zhang et al. | A novel method for preparing ultrafine molybdenum powder | |
| US3475158A (en) | Production of particulate,non-pyrophoric metals and product | |
| Mai et al. | Preparation of highly uniform molybdenum powder by the short-process reduction of molybdenum trioxide with hydrogen | |
| Wang et al. | A facile pathway to prepare ultrafine WC powder via a carbothermic pre-reduction followed by carbonization with CH4-H2 mixed gases | |
| Pan et al. | Preparation of nano-sized tungsten carbide via fluidized bed | |
| CN115365511B (en) | Gas-phase reduction and collection device and method for narrow-distribution superfine molybdenum powder | |
| Shi et al. | Synthesis of multi-walled carbon nanotube–tungsten carbide composites by the reduction and carbonization process | |
| US3989511A (en) | Metal powder production by direct reduction in an arc heater | |
| CN115889760A (en) | Device and method for rapidly preparing carbon nanotube coated superfine high-entropy alloy composite powder |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |