CN117963924B - Preparation method of nano tungsten carbide - Google Patents
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- UONOETXJSWQNOL-UHFFFAOYSA-N tungsten carbide Chemical compound [W+]#[C-] UONOETXJSWQNOL-UHFFFAOYSA-N 0.000 title claims abstract description 56
- 238000002360 preparation method Methods 0.000 title claims abstract description 23
- QGLKJKCYBOYXKC-UHFFFAOYSA-N nonaoxidotritungsten Chemical compound O=[W]1(=O)O[W](=O)(=O)O[W](=O)(=O)O1 QGLKJKCYBOYXKC-UHFFFAOYSA-N 0.000 claims abstract description 39
- 229910001930 tungsten oxide Inorganic materials 0.000 claims abstract description 39
- 239000000463 material Substances 0.000 claims abstract description 36
- 239000000843 powder Substances 0.000 claims abstract description 28
- 238000003763 carbonization Methods 0.000 claims abstract description 27
- 238000000034 method Methods 0.000 claims abstract description 25
- 239000006229 carbon black Substances 0.000 claims abstract description 18
- 238000002156 mixing Methods 0.000 claims abstract description 16
- 239000005539 carbonized material Substances 0.000 claims abstract description 15
- 238000002161 passivation Methods 0.000 claims abstract description 15
- 238000001354 calcination Methods 0.000 claims abstract description 12
- QGZKDVFQNNGYKY-UHFFFAOYSA-O Ammonium Chemical compound [NH4+] QGZKDVFQNNGYKY-UHFFFAOYSA-O 0.000 claims abstract description 9
- 239000002245 particle Substances 0.000 claims description 17
- 238000004321 preservation Methods 0.000 claims description 14
- 238000005469 granulation Methods 0.000 claims description 12
- 230000003179 granulation Effects 0.000 claims description 12
- 239000012298 atmosphere Substances 0.000 claims description 11
- 239000007921 spray Substances 0.000 claims description 11
- 239000000203 mixture Substances 0.000 claims description 10
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 claims description 6
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 6
- 230000002829 reductive effect Effects 0.000 claims description 6
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims description 5
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 claims description 4
- 229910002091 carbon monoxide Inorganic materials 0.000 claims description 4
- 229910052786 argon Inorganic materials 0.000 claims description 3
- 239000001257 hydrogen Substances 0.000 claims description 3
- 229910052739 hydrogen Inorganic materials 0.000 claims description 3
- 229910052757 nitrogen Inorganic materials 0.000 claims description 3
- 239000011261 inert gas Substances 0.000 claims description 2
- 238000010000 carbonizing Methods 0.000 claims 1
- 238000004519 manufacturing process Methods 0.000 abstract description 6
- 239000013078 crystal Substances 0.000 abstract description 5
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 abstract description 5
- 239000011858 nanopowder Substances 0.000 abstract description 2
- 229910052721 tungsten Inorganic materials 0.000 abstract description 2
- 239000010937 tungsten Substances 0.000 abstract description 2
- ZNOKGRXACCSDPY-UHFFFAOYSA-N tungsten trioxide Chemical compound O=[W](=O)=O ZNOKGRXACCSDPY-UHFFFAOYSA-N 0.000 description 14
- 238000005516 engineering process Methods 0.000 description 7
- 239000007789 gas Substances 0.000 description 7
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 6
- 239000012535 impurity Substances 0.000 description 6
- 238000001878 scanning electron micrograph Methods 0.000 description 6
- 238000002441 X-ray diffraction Methods 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 4
- 238000001035 drying Methods 0.000 description 4
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 3
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 3
- 238000000498 ball milling Methods 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 3
- 238000007599 discharging Methods 0.000 description 3
- 229910002804 graphite Inorganic materials 0.000 description 3
- 239000010439 graphite Substances 0.000 description 3
- 239000007791 liquid phase Substances 0.000 description 3
- 238000011068 loading method Methods 0.000 description 3
- 239000012071 phase Substances 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- 238000009827 uniform distribution Methods 0.000 description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 239000012299 nitrogen atmosphere Substances 0.000 description 2
- 238000010532 solid phase synthesis reaction Methods 0.000 description 2
- 238000001308 synthesis method Methods 0.000 description 2
- 238000005054 agglomeration Methods 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000012300 argon atmosphere Substances 0.000 description 1
- 230000003197 catalytic effect Effects 0.000 description 1
- 239000010406 cathode material Substances 0.000 description 1
- 238000010924 continuous production Methods 0.000 description 1
- 238000006356 dehydrogenation reaction Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000000713 high-energy ball milling Methods 0.000 description 1
- 238000003837 high-temperature calcination Methods 0.000 description 1
- 238000005984 hydrogenation reaction Methods 0.000 description 1
- 238000009776 industrial production Methods 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 238000006317 isomerization reaction Methods 0.000 description 1
- 238000000634 powder X-ray diffraction Methods 0.000 description 1
- 239000010970 precious metal Substances 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
Abstract
The invention belongs to the technical field of nano powder, and particularly relates to a preparation method of nano tungsten carbide. The invention provides a preparation method of nano tungsten carbide, which comprises the following steps: calcining ammonium metatungstate to obtain tungsten oxide agglomerates; mixing the tungsten oxide agglomerates with carbon black, and granulating to obtain a spherical material; and sequentially carrying out reduction carbonization and passivation on the spherical material to obtain the nano tungsten carbide. The invention provides a method for preparing nano tungsten carbide powder by adopting a dynamic reduction carbonization method. The preparation method firstly prepares the pre-carbonized material with uniformly dispersed crystal grains, and prepares the high-quality nano tungsten carbide on the basis. The preparation method provided by the invention has the advantages of simple process, low production cost and easiness in realizing industrialization; the obtained nano tungsten carbide has high purity and good dispersibility, and further improves the technical level and the product quality of the deep processing and application products in the tungsten industry.
Description
Technical Field
The invention belongs to the technical field of nano powder, and particularly relates to a preparation method of nano tungsten carbide.
Background
The nano tungsten carbide powder is a novel functional material with high hardness, high thermal stability and high wear resistance, breaks through the restriction that the high hardness and the high toughness of the traditional hard alloy can not be achieved, and has wide application prospect in the fields of tools, precision dies, drills and the like. Meanwhile, the nano tungsten carbide has excellent catalytic performance, so that the nano tungsten carbide can be used for hydrogenation, dehydrogenation, isomerization and other reactions, and can replace some precious metals to be used as cathode materials in battery materials.
The preparation method of the nano tungsten carbide mainly comprises three methods, namely a solid phase method, a gas phase method and a liquid phase method. The conventional vapor synthesis method has the characteristics of expensive equipment, complex process, high cost and the like, so that the industrialized application of the conventional vapor synthesis method is restricted. The liquid phase method has simple preparation process and high purity, but the liquid phase method generally uses various solvents and can also carry out reaction for a period of time under the condition of high temperature, so that certain requirements are put on large-scale industrial production. The traditional solid phase method generally needs high-temperature calcination and high-energy ball milling, the preparation cost is high, and the prepared nano WC particles are easy to have the problems of non-uniformity and impurity introduction.
Disclosure of Invention
The invention aims to provide a preparation method of nano tungsten carbide, which has the advantages of simple process, low production cost, high purity and good dispersibility.
In order to achieve the above object, the present invention provides the following technical solutions:
the invention provides a preparation method of nano tungsten carbide, which comprises the following steps:
Calcining ammonium metatungstate to obtain tungsten oxide agglomerates;
Crushing the tungsten oxide agglomerates, mixing the crushed tungsten oxide agglomerates with carbon black, and granulating to obtain spherical materials; the particle size of the tungsten oxide powder obtained after crushing is less than or equal to 0.5 mu m;
And sequentially carrying out reduction carbonization and passivation on the spherical material to obtain the nano tungsten carbide.
Preferably, the calcination temperature is 750-850 ℃, and the heat preservation time is 4-6 hours.
Preferably, the crushing mode is air flow mill crushing; the air flow rate of the jet mill is 150-200 m 3/h, the air pressure is 0.03-0.06 MPa, and the time is 30-50 min.
Preferably, the mass ratio of the tungsten oxide powder to the carbon black is 5:1 or 1:0.19.
Preferably, the reduction carbonization temperature is 850-1100 ℃, and the heat preservation time is 30-60 min.
Preferably, the reductive carbonization is performed in an inert atmosphere; the inert gas includes nitrogen and/or argon.
Preferably, the reduction carbonization is performed in a rotary reduction furnace;
The rotary reduction furnace sequentially comprises a first temperature zone, a second temperature zone, a third temperature zone, a fourth temperature zone, a fifth temperature zone and a sixth temperature zone from the furnace end to the furnace tail;
The temperature of the first temperature zone is 850-880 ℃; the temperature of the second temperature zone is 880-910 ℃; the temperature of the third temperature zone is 910-930 ℃; the temperature of the fourth temperature zone is 930-950 ℃; the temperature of the fifth temperature zone is 980-1000 ℃; the temperature of the sixth temperature zone is 980-1080 ℃;
the rotation speed of the materials in the rotary reduction furnace is 3-6 r/min.
Preferably, the passivation temperature is 1400-1500 ℃, and the heat preservation time is 20-40 min.
Preferably, the passivation is performed in a reducing atmosphere;
the reducing atmosphere comprises carbon monoxide and/or hydrogen.
Preferably, the specific surface area of the nano tungsten carbide is 3.5-4.3 m 2/g.
The invention provides a preparation method of nano tungsten carbide, which comprises the following steps: calcining ammonium metatungstate to obtain tungsten oxide agglomerates; crushing the tungsten oxide agglomerates, mixing the crushed tungsten oxide agglomerates with carbon black, and granulating to obtain spherical materials; the particle size of the tungsten oxide powder obtained after crushing is less than or equal to 0.5 mu m; and sequentially carrying out reduction carbonization and passivation on the spherical material to obtain the nano tungsten carbide. The invention provides a method for preparing nano tungsten carbide powder by adopting a dynamic reduction carbonization method. The preparation method firstly prepares WC and W 2 C pre-carbonized material with uniformly dispersed crystal grains, and prepares high-quality nano tungsten carbide on the basis. The preparation method provided by the invention has the advantages of simple process, low production cost and easiness in realizing industrialization; the obtained nano tungsten carbide has high purity and good dispersibility, and further improves the technical level and the product quality of the deep processing and application products in the tungsten industry.
Drawings
FIG. 1 is an SEM image of tungsten oxide agglomerates and industrial tungsten trioxide obtained in example 1;
FIG. 2 is an SEM image of spherical materials and nano-tungsten carbide obtained in example 1, wherein (a) and (b) are spherical materials and (c) and (d) are nano-tungsten carbide;
FIG. 3 is an XRD pattern of the pre-carbonized material obtained in example 1;
FIG. 4 is an XRD pattern of nano-tungsten carbide obtained in example 1;
FIG. 5 is an SEM image of the nano-tungsten carbide powder obtained in example 1 after gas-flow crushing.
Detailed Description
The invention provides a preparation method of nano tungsten carbide, which comprises the following steps:
Calcining ammonium metatungstate to obtain tungsten oxide agglomerates;
Crushing the tungsten oxide agglomerates, mixing the crushed tungsten oxide agglomerates with carbon black, and granulating to obtain spherical materials; the particle size of the tungsten oxide powder obtained after crushing is less than or equal to 0.5 mu m;
And sequentially carrying out reduction carbonization and passivation on the spherical material to obtain the nano tungsten carbide.
In the present invention, all the preparation materials are commercially available products well known to those skilled in the art unless specified otherwise.
The invention calcines ammonium metatungstate to obtain tungsten oxide aggregate.
In the invention, the calcination temperature is preferably 750-850 ℃, more preferably 780-830 ℃, and even more preferably 800-810 ℃; the heat preservation time is preferably 4 to 6 hours, more preferably 4 to 5 hours. In the present invention, the calcination is preferably performed in a muffle furnace.
After the tungsten oxide aggregate is obtained, crushing the tungsten oxide aggregate, mixing the crushed tungsten oxide aggregate with carbon black, and granulating to obtain a spherical material; the particle size of the tungsten oxide powder obtained after crushing is less than or equal to 0.5 mu m.
In the invention, the crushing mode is preferably air flow mill crushing; the air flow rate of the jet mill crushing is preferably 150-200 m 3/h, and the air pressure is preferably 0.03-0.06 MPa; the time is preferably 30-50 min. In the invention, the particle size of the tungsten oxide powder obtained after crushing is less than or equal to 0.5 mu m. In the invention, the mass ratio of the tungsten oxide powder to the carbon black is preferably 5:1 or 1:0.19. in the present invention, the mixing is preferably carried out using a vertical coulter. In the traditional process for preparing nano tungsten carbide powder, carbon black is generally mixed in raw materials in a ball milling mixing mode, and impurity elements such as iron are introduced due to the fact that the ball milling method is used for uniformly mixing the carbon black for a long time, so that the purity of a product is reduced. In the invention, the tungsten trioxide agglomerates are fully crushed by adopting an airflow crushing method, so that the time for ball milling and mixing is greatly reduced, and the introduction of impurity elements is avoided.
In the present invention, the granulation method is preferably spray granulation. The process of the spray granulation is not particularly limited, and may be employed as is well known to those skilled in the art.
After the spherical material is obtained, the spherical material is subjected to reduction carbonization and passivation in sequence, so that the nano tungsten carbide is obtained.
In the invention, the reduction carbonization temperature is preferably 850-1100 ℃, and more preferably 900-1000 ℃; the heat preservation time is preferably 30-60 min, more preferably 40-50 min. In the present invention, the reductive carbonization is preferably performed in an inert atmosphere; the inert atmosphere preferably comprises nitrogen and/or argon.
In the present invention, the reduction carbonization is preferably performed in a rotary reduction furnace; the rotary reduction furnace preferably comprises a first temperature zone, a second temperature zone, a third temperature zone, a fourth temperature zone, a fifth temperature zone and a sixth temperature zone from the furnace head to the furnace tail in sequence; the temperature of the first temperature zone is preferably 850-880 ℃; the temperature of the second temperature zone is preferably 880-910 ℃; the temperature of the third temperature zone is preferably 910-930 ℃; the temperature of the fourth temperature zone is preferably 930-950 ℃; the temperature of the fifth temperature zone is preferably 980-1000 ℃; the temperature of the sixth temperature zone is preferably 980-1080 ℃. In the invention, the rotation speed of the materials in the rotary reduction furnace is preferably 3-6 r/min, and more preferably 4-5 r/min.
The invention adopts a rotary reduction furnace with six temperature zones to prepare the pre-carbonized material. The traditional one-step method for preparing the nano tungsten carbide adopts a tubular furnace for reaction, and the tubular furnace often has the problem of uneven temperature, so that the produced product has poor consistency and has the conditions of poor grain size and uneven grain size distribution. The rotary reduction furnace with multiple temperature zones has good temperature uniformity, better control of temperature parameters, continuous production, timely adjustment aiming at the problems of incomplete carbonization and the like possibly occurring in products, ensures the quality of the products, greatly improves the production efficiency and has great industrial potential.
In the present invention, the components of the pre-carbonized material obtained after the reductive carbonization preferably include WC and W 2 C.
In the invention, the passivation temperature is preferably 1400-1500 ℃, and more preferably 1300 ℃; the holding time is preferably 20 to 40 minutes, more preferably 30 minutes. In the present invention, the passivation is preferably performed in a reducing atmosphere; the reducing atmosphere preferably comprises carbon monoxide and/or hydrogen.
In the invention, the specific surface area of the nano tungsten carbide is preferably 3.5-4.3 m 2/g.
For further explanation of the present invention, a method for preparing nano tungsten carbide according to the present invention is described in detail with reference to the accompanying drawings and examples, but they should not be construed as limiting the scope of the present invention.
Example 1
Loading ammonium metatungstate into an alumina crucible, and calcining by a muffle furnace at 700 ℃ for 4 hours to obtain tungsten oxide agglomerates;
crushing the obtained tungsten oxide aggregate by adopting an air flow mill for 30min, wherein the air flow is 150m 3/h, the air pressure is 0.06MPa, and the crushed tungsten oxide (the particle size is 0.5 mu m) and high-purity carbon black are mixed according to the following ratio of 1: mixing materials by a vertical coulter according to the mass ratio of 0.19, and performing spray granulation on the obtained mixture by adopting a spray granulation technology and a normal-temperature second drying technology to obtain a spherical material;
Adopting a rotary reduction furnace with six temperature zones, carrying out reduction carbonization on the obtained spherical material under the protection of nitrogen atmosphere, wherein the temperatures of the six temperature zones from a furnace end to a furnace tail are 850 ℃, 880 ℃, 910 ℃, 950 ℃, 980 ℃ and 980 ℃ respectively, the rotation speed of the material is 3r/min, the heat preservation time from feeding to discharging is 60min, and the pre-carbonized material with the chemical composition of WC+W 2 C is obtained;
Passivating the obtained pre-carbonized material in carbon monoxide atmosphere by adopting a molybdenum wire furnace, wherein the passivating temperature is 1400 ℃, the heat preservation time is 30min, and the nano tungsten carbide with complete crystal grains and uniform distribution is obtained after passivation, and the specific surface area of the nano tungsten carbide powder is 3.71m 2/g.
Example 2
Loading ammonium metatungstate into an alumina crucible, and calcining by a muffle furnace at 750 ℃ for 6 hours to obtain tungsten oxide agglomerates;
Crushing the obtained tungsten oxide aggregate by adopting an air flow mill for 45min, wherein the air flow is 180m 3/h, the air pressure is 0.05MPa, and the crushed tungsten oxide (the particle size is 0.5 mu m) and high-purity carbon black are mixed according to a proportion of 5:1, mixing materials by a vertical coulter according to the mass ratio, and performing spray granulation on the obtained mixture by adopting a spray granulation technology and a normal-temperature second drying technology to obtain a spherical material;
Adopting a rotary reduction furnace with six temperature zones, carrying out reduction carbonization on the obtained spherical material under the protection of nitrogen atmosphere, wherein the temperatures of the six temperature zones from a furnace head to a furnace tail are 880 ℃, 910 ℃, 930 ℃, 990 ℃ and 990 ℃, the rotation speed of the material is 5r/min, the heat preservation time from feeding to discharging is 40min, and the pre-carbonized material with the chemical composition of WC+W 2 C is obtained;
Passivating the obtained pre-carbonized material in hydrogen gas by adopting a molybdenum wire furnace, wherein the passivating temperature is 1450 ℃, the heat preservation time is 20min, and the nano tungsten carbide with complete crystal grains and uniform distribution is obtained after passivation, and the specific surface area of the nano tungsten carbide powder is 4.13m 2/g.
Example 3
Loading ammonium metatungstate into an alumina crucible, and calcining by a muffle furnace at 700 ℃ for 4 hours to obtain tungsten oxide agglomerates;
Crushing the obtained tungsten oxide aggregate by adopting an air flow mill for 30min, wherein the air flow is 200m 3/h, the air pressure is 0.03MPa, and the crushed tungsten oxide (the particle size is 0.5 mu m) and high-purity carbon black are mixed according to a proportion of 5:1, mixing materials by a vertical coulter according to the mass ratio, and performing spray granulation on the obtained mixture by adopting a spray granulation technology and a normal-temperature second drying technology to obtain a spherical material;
adopting a rotary reduction furnace with six temperature zones, carrying out reduction carbonization on the obtained spherical material under the protection of argon atmosphere, wherein the temperatures of the six temperature zones from a furnace end to a furnace tail are 880 ℃, 910 ℃, 930 ℃, 950 ℃, 1000 ℃ and 1080 ℃, the advancing speed of the material is 6r/min, the heat preservation time from feeding to discharging is 35min, and the pre-carbonized material with the chemical composition of WC+W 2 C is obtained;
Passivating the obtained pre-carbonized material in hydrogen gas by adopting a molybdenum wire furnace, wherein the passivating temperature is 1500 ℃, the heat preservation time is 20min, and the nano tungsten carbide with complete crystal grains and uniform distribution is obtained after passivation, and the specific surface area of the nano tungsten carbide powder is 3.96m 2/g.
Comparative example 1
1. Uniformly mixing nano tungsten powder with BET of 6.0m 2/g and carbon black according to a certain proportion to obtain W+C;
2. And placing the uniformly mixed W+C in a graphite boat, ensuring the total height of the boat to be unchanged, superposing and placing the two boats, controlling the stacking density of the boats to be 1.75g/cm 3, and placing the boats into a molybdenum wire furnace for carbonization for 4 hours at 1050 ℃.
3. Performing gas breaking on the carbonized tungsten carbide blocks, wherein the gas breaking pressure is 8bar, and the rotating speed of a grading wheel is 4000r/min;
4. the specific surface area of the WC produced was 2.95m 2/g.
Comparative example 2
1. Uniformly mixing nano tungsten powder with BET of 8.0m 2/g and carbon black according to a certain proportion to obtain W+C;
2. And placing the uniformly mixed W+C in a graphite boat, ensuring the total height of the boat to be unchanged, superposing and placing the two boats, controlling the stacking density of the boats to be 1.75g/cm 3, and placing the boats into a molybdenum wire furnace for carbonization for 3h at 1100 ℃.
3. Performing gas breaking on the carbonized tungsten carbide blocks, wherein the gas breaking pressure is 10bar, and the rotating speed of a grading wheel is 4800r/min;
4. the specific surface area of the WC is 3.2m 2/g.
Comparative example 3
1. Uniformly mixing nano tungsten powder with BET of 10.0m 2/g and carbon black according to a certain proportion to obtain W+C;
2. And placing the uniformly mixed W+C in a graphite boat, ensuring the total height of the boat to be unchanged, superposing and placing the three boats, controlling the stacking density of the three boats to be 1.52g/cm 3, and placing the three boats into a molybdenum wire furnace for carbonization for 3h at 1100 ℃.
3. Performing gas breaking on the carbonized tungsten carbide blocks, wherein the gas breaking pressure is 9bar, and the rotating speed of a grading wheel is 4500r/min;
4. The specific surface area of the WC is 3.05m 2/g.
As can be seen from comparison of examples 1-3 and comparative examples 1-3, the WC obtained by the preparation method provided by the invention has higher specific surface area, and the preparation method provided by the invention is simpler, more convenient and more efficient.
Performance testing
FIG. 1 is a SEM image of the tungsten oxide agglomerates obtained in example 1, wherein FIG. 1 (a) is a tungsten oxide agglomerate and FIG. 1 (b) is a conventional industrial tungsten trioxide, and it can be seen from FIG. 1 that the AMT calcined tungsten trioxide particles are fine, have a particle size of less than 0.5 μm, whereas conventional industrial tungsten trioxide particles are coarse, have an average particle size of about 25 μm, and are unsuitable for the production of nano tungsten carbide.
Fig. 2 is an SEM image of the spherical material and nano tungsten carbide obtained in example 1, wherein (a) and (b) of fig. 2 are spherical materials, and (c) and (d) of fig. 2 are nano tungsten carbide, as can be seen from fig. 2: the mixture of spherical WO 3 +C formed by low-power spray granulation and normal-temperature second drying technology has uneven surface and loose structure (fig. 2 (a)); the tungsten trioxide and the carbon black are uniformly distributed under high power, so that the subsequent carbonization is facilitated to prepare tungsten carbide powder (fig. 2 (b)); the graph c shows that the spherical structure of spray granulation is inherited due to the inheritance of the powder, so that WC aggregate with the spherical structure is formed, the surface of the WC aggregate is coarser than that of the spherical material, the structure is looser, WC particles are fine at high power (fig. 2 (d)), the particle size is about 100nm, and the WC aggregate is easy to crush in the subsequent airflow crushing process to form nano tungsten carbide powder with better dispersibility.
Fig. 3 is an XRD pattern of the pre-carbonized material obtained in example 1, as can be seen from fig. 3: the reduction and partial carbonization of tungsten trioxide are completed in a rotary reduction furnace, and two phases, namely W 2 C, WC phase, exist, and a subsequent passivation process is required to realize complete carbonization.
Fig. 4 is an XRD pattern of nano-tungsten carbide obtained in example 1, as can be seen from fig. 4: only the characteristic peak of WC exists in the passivated tungsten carbide powder XRD spectrum, which indicates that the pre-carbonized material is completely carbonized, and the tungsten carbide powder is prepared. Combining the results in fig. 2 (d) and fig. 4, it is demonstrated that the process successfully produced nano tungsten carbide powder.
The elemental composition of the nano tungsten carbide powder obtained in example 1 was tested, and table 1 shows the impurity element content scale of the nano tungsten carbide powder;
TABLE 1 impurity element content table of nano tungsten carbide powder obtained in example 1
As can be seen from Table 1, the impurity element content of the powder is lower than the national standard of nano tungsten carbide, and the purity is higher.
The nano tungsten carbide of example 1 was subjected to air-flow crushing, and fig. 5 is an SEM image of the nano tungsten carbide powder after air-flow crushing, and it can be seen from fig. 5 that the nano tungsten carbide powder has no obvious agglomeration, and the particles are uniform and have good dispersibility.
Although the foregoing embodiments have been described in some, but not all embodiments of the invention, other embodiments may be obtained according to the present embodiments without departing from the scope of the invention.
Claims (7)
1. The preparation method of the nano tungsten carbide is characterized by comprising the following steps of:
Calcining ammonium metatungstate to obtain tungsten oxide agglomerates;
crushing the tungsten oxide agglomerates, and mixing the crushed tungsten oxide agglomerates with carbon black to obtain a mixture; the particle size of the tungsten oxide powder obtained after crushing is less than or equal to 0.5 mu m;
carrying out spray granulation on the mixture to obtain a spherical material;
reducing and carbonizing the spherical material to obtain a pre-carbonized material;
Passivating the pre-carbonized material to obtain the nano tungsten carbide;
the heat preservation time of the reduction carbonization is 30-60 min;
the reduction carbonization is carried out in a rotary reduction furnace;
The rotary reduction furnace sequentially comprises a first temperature zone, a second temperature zone, a third temperature zone, a fourth temperature zone, a fifth temperature zone and a sixth temperature zone from the furnace end to the furnace tail; the temperature of the first temperature zone is 850-880 ℃; the temperature of the second temperature zone is 880-910 ℃; the temperature of the third temperature zone is 910-930 ℃; the temperature of the fourth temperature zone is 930-950 ℃; the temperature of the fifth temperature zone is 980-1000 ℃; the temperature of the sixth temperature zone is 980-1080 ℃;
the rotation speed of the materials in the rotary reduction furnace is 3-6 r/min;
the passivation is performed in a reducing atmosphere; the reducing atmosphere comprises carbon monoxide and/or hydrogen.
2. The preparation method of claim 1, wherein the calcination temperature is 750-850 ℃, and the heat preservation time is 4-6 hours.
3. The method according to claim 1, wherein the crushing means is jet mill crushing; the air flow rate of the jet mill is 150-200 m 3/h, the air pressure is 0.03-0.06 MPa, and the time is 30-50 min.
4. The preparation method according to claim 1, wherein the mass ratio of the tungsten oxide powder to the carbon black is 5:1 or 1:0.19.
5. The method of claim 1, wherein the reductive carbonization is performed in an inert atmosphere; the inert gas includes nitrogen and/or argon.
6. The method according to claim 1, wherein the passivation temperature is 1400-1500 ℃ and the heat preservation time is 20-40 min.
7. The preparation method of claim 1, wherein the specific surface area of the nano tungsten carbide is 3.5-4.3 m 2/g.
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| CN202410361531.7A CN117963924B (en) | 2024-03-28 | Preparation method of nano tungsten carbide |
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| 孙鹏.纳米碳化钨催化剂的研究.中国优秀博硕士学位论文全文数据库 (硕士)工程科技Ⅰ辑.2005,第12-24页. * |
| 纳米W粉阶段碳化制备纳米WC粉的工艺及机制研究;叶楠等;稀有金属;20170731;第41卷(第7期);第775-782页 * |
| 纳米碳化钨催化剂的研究;孙鹏;中国优秀博硕士学位论文全文数据库 (硕士)工程科技Ⅰ辑;20050915;第12-24页 * |
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