Method for preparing fine-particle tungsten powder by using dust collecting material generated by rotary furnace for producing tungsten powder

Abstract

The invention relates to the technical field of powder metallurgy, in particular to a method for preparing fine-particle tungsten powder by using a dust collecting material generated by a rotary furnace for producing tungsten powder, the dust collecting material generated by the rotary furnace for producing the tungsten powder and tungsten oxide are used, and the tungsten powder with the same quality as that prepared by adopting normal tungsten oxide can be stably prepared. And the problem that an existing dust collecting material is difficult to recycle is solved, the production efficiency is improved, and the productivity of tungsten powder is greatly improved.

Description

Technical Field

[0001] The invention relates to the technical field of powder metallurgy, in particular to a method for preparing fine-grained tungsten powder by using dust collected from a rotary furnace for producing tungsten powder. Background Art

[0002] Tungsten has the advantages of high melting point, good thermal conductivity, strong radiation absorption ability, excellent high temperature strength and good corrosion resistance. It is widely used in various industrial fields such as mining, metallurgy, machinery, construction, transportation, electronics, chemical industry, light industry, textile, military industry, aerospace and science and technology. The performance of tungsten powder (such as purity, particle size, particle size composition, etc.) mainly depends on the reduction equipment and reduction process. At present, the main equipment for producing tungsten powder includes 14-tube reduction furnace, 15-tube reduction furnace and rotary furnace. Among them, the rotary furnace is used in the reduction and preparation of fine-grained tungsten powder. It has the advantages of high output and good product quality stability, and has become the main production equipment for preparing fine-grained tungsten powder in recent years. However, due to the characteristics of the equipment, 10~30wt% of dust is also produced while producing tungsten powder. The traditional method of treating dust is to firstly subject the dust to high-temperature oxidation treatment to obtain tungsten oxide, and then subject the tungsten oxide to high-temperature reduction to prepare tungsten powder. The process is complicated and energy-intensive. Summary of the invention

[0003] In view of the technical problems existing in the prior art, the present invention provides a method for preparing fine particle tungsten powder using dust collected from a rotary furnace for producing tungsten powder.

[0004] According to one aspect of the present invention, the present invention provides the following technical solution: A method for preparing fine-grained tungsten powder using dust collected from a rotary furnace for producing tungsten powder comprises the following steps: S1. Mixing the dust collecting material with tungsten oxide to obtain a mixture of tungsten oxide and the dust collecting material; S2, reducing the mixture at high temperature in a reducing atmosphere to obtain tungsten powder; S3. Sieve the tungsten powder to obtain uniform fine-grained tungsten powder.

[0005] The beneficial effects of the present invention are as follows: The present invention provides a method for preparing fine-grained tungsten powder by using dust collected by a rotary kiln for producing tungsten powder. By using the dust collected by a rotary kiln for producing tungsten powder and tungsten oxide, tungsten powder of the same quality as that prepared by using normal tungsten oxide can be stably prepared, and the problem of difficulty in recycling the existing dust collected can be solved, thereby improving production efficiency and greatly increasing the production capacity of tungsten powder. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0007] Figure 1 This is an electron microscope photograph of the fine-grained tungsten powder prepared in Example 1; Figure 2 This is an electron microscope photograph of the fine-grained tungsten powder prepared in Example 2; Figure 3 This is an electron microscope photograph of the fine-grained tungsten powder prepared in Example 3; Figure 4 This is an electron microscope photograph of the fine-grained tungsten powder prepared in Example 4; Figure 5 This is an electron microscope photograph of the fine-grained tungsten powder prepared in Comparative Example 1; Figure 6 This is an electron microscope photograph of the fine-grained tungsten powder prepared in Comparative Example 2; Figure 7 This is an electron microscope photograph of the fine-grained tungsten powder prepared in Comparative Example 3; Figure 8 This is an electron microscope photograph of the fine-grained tungsten powder prepared in Comparative Example 4.

[0008] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0009] The following will be described clearly and completely in conjunction with the technical solutions in the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0010] According to one aspect of the present invention, the present invention provides the following technical solution: A method for preparing fine-grained tungsten powder using dust collected from a rotary furnace for producing tungsten powder comprises the following steps: S1. Mixing the dust collecting material with tungsten oxide (tungsten oxide used in normal production) to obtain a mixture of tungsten oxide and dust collecting material; S2, reducing the mixture at high temperature in a reducing atmosphere to obtain tungsten powder; S3. Sieve the tungsten powder to obtain uniform fine-grained tungsten powder.

[0011] Preferably, in step S1, the dust collecting material includes tungsten trioxide, intermediate tungsten oxide and incompletely reacted tungsten powder.

[0012] Preferably, in step S1, the mass ratio of the dust collecting material to tungsten oxide is 1:(3-5). Specifically, the mass ratio of the dust collecting material to tungsten oxide can be, for example, any one of 1:3, 1:3.5, 1:4, 1:4.5, 1:5, or a range between any two thereof.

[0013] Preferably, in step S1, a double cone mixer is used for mixing, the mixing time is 30 to 60 minutes, and the mixing speed is 6.0 to 10.0 r / min. Specifically, the mixing time can be, for example, any one of 30 minutes, 35 minutes, 40 minutes, 45 minutes, 50 minutes, 55 minutes, and 60 minutes, or a range between any two of them. The mixing speed can be, for example, any one of 6.0 r / min, 7.0 r / min, 8.0 r / min, 9.0 r / min, and 10.0 r / min, or a range between any two of them.

[0014] Preferably, in step S2, the reduction process is carried out in a rotary kiln, the feed rate of the mixed material during the reduction process is 100-280 kg / h, the reduction temperature is 610-1020° C., and the reduction atmosphere flow rate is 400-550 m 3 / h, the rotating speed of the rotary kiln is 3-6r / min, and the reducing atmosphere is hydrogen. Specifically, the mixed material feeding speed during the reduction process can be, for example, 100kg / h, 110kg / h, 120kg / h, 130kg / h, 140kg / h, 150kg / h, 160kg / h, 170kg / h, 180kg / h, 190kg / h, 200kg / h, 210kg / h, 220kg / h, 230kg / h, 240kg / h, 250kg / h, 260kg / h, 270kg / h, 280kg / h, any one or the range between any two. The reduction temperature can be, for example, 610°C, 650°C, 700°C, 750°C, 800°C, 850°C, 900°C, 950°C, 1000°C, 1020°C, any one or the range between any two. The reducing atmosphere flow rate can be, for example, 400 m 3 / h、410m 3 / h、420m 3 / h、430m 3 / h、440m 3 / h、450m 3 / h、460m 3 / h、470m 3 / h、480m 3 / h、490m 3 / h、500m 3 / h、510m 3 / h、520m 3 / h、530m 3 / h、540m 3 / h、550m 3 The rotation speed of the rotary kiln can be, for example, any one of 3 r / min, 4 r / min, 5 r / min, 6 r / min, or any range between two thereof.

[0015] Preferably, in step S2, the rotary kiln includes six temperature zones with successively increasing temperatures from the feeding point to the discharging point.

[0016] Preferably, in step S3, the mesh size of the sieve is 80-100 meshes, and the sieve frequency is 30-50 Hz.

[0017] Preferably, in step S3, the ground FSSS particle size of the tungsten powder is 0.70-1.0 μm, and the specific surface area is 2-4 m2 / g.

[0018] The technical solution of the present invention is further described below in conjunction with specific embodiments.

[0019] Example 1 A method for preparing fine-grained tungsten powder using dust collected from a rotary furnace for producing tungsten powder comprises the following steps: S1. 2 tons of dust collecting material and 6 tons of tungsten oxide are mixed with a double cone mixer at a mixing time of 60 minutes and a mixing speed of 6.0 r / min to obtain a mixture of tungsten oxide and dust collecting material; S2. The mixture is subjected to high-temperature reduction in a reducing atmosphere to obtain tungsten powder; the reduction process is carried out in a rotary furnace, the feed rate of the mixture during the reduction process is 110 kg / h, the reduction temperature is: the first zone temperature is 610°C, the second zone temperature is 650°C, the third zone temperature is 700°C, the fourth zone temperature is 750°C, the fifth zone temperature is 850°C, and the sixth zone temperature is 920°C; the reducing atmosphere flow rate is 550m 3 / h, the rotating speed of the rotary kiln is 5r / min, and the reducing atmosphere is hydrogen; S3, pass the tungsten powder through an 80-mesh linear sieve to obtain uniform fine-grained tungsten powder, such as Figure 1 As shown, the BET specific surface area of ​​tungsten powder is 3.5±0.5㎡ / g.

[0020] Example 2 A method for preparing fine-grained tungsten powder using dust collected from a rotary furnace for producing tungsten powder comprises the following steps: S1. 1.5 tons of dust collecting material and 6 tons of tungsten oxide are mixed with a double cone mixer at a mixing time of 60 minutes and a mixing speed of 10.0 r / min to obtain a mixture of tungsten oxide and dust collecting material; S2. The mixed material is subjected to high-temperature reduction in a reducing atmosphere to obtain tungsten powder; the reduction process is carried out in a rotary furnace, the mixed material feed rate during the reduction process is 129.5 kg / h, the reduction temperature is: the first zone temperature is 590°C, the second zone temperature is 650°C, the third zone temperature is 690°C, the fourth zone temperature is 750°C, the fifth zone temperature is 860°C, and the sixth zone temperature is 940°C; the reducing atmosphere flow rate is 530m 3 / h, the rotating speed of the rotary kiln is 5r / min, and the reducing atmosphere is hydrogen; S3, pass the tungsten powder through an 80-mesh linear sieve to obtain uniform fine-grained tungsten powder, such as Figure 2 As shown, the BET specific surface area of ​​tungsten powder is 2.5±0.5㎡ / g.

[0021] Example 3 A method for preparing fine-grained tungsten powder using dust collected from a rotary furnace for producing tungsten powder comprises the following steps: S1. 1.5 tons of dust collecting material and 6 tons of tungsten oxide are mixed with a double cone mixer at a mixing time of 60 minutes and a mixing speed of 8.0 r / min to obtain a mixture of tungsten oxide and dust collecting material; S2. The mixed material is subjected to high-temperature reduction in a reducing atmosphere to obtain tungsten powder; the reduction process is carried out in a rotary furnace, the mixed material feed rate during the reduction process is 230 kg / h, the reduction temperature is: the first zone temperature is 750°C, the second zone temperature is 830°C, the third zone temperature is 900°C, the fourth zone temperature is 910°C, the fifth zone temperature is 930°C, and the sixth zone temperature is 950°C; the reducing atmosphere flow rate is 500m 3 / h, the rotary kiln speed is 5r / min, the reducing atmosphere is hydrogen; the ground FSSS particle size of tungsten powder is 0.80±0.05μm; S3, pass the tungsten powder through an 80-mesh linear sieve to obtain uniform fine-grained tungsten powder, such as Figure 3 shown.

[0022] Example 4 A method for preparing fine-grained tungsten powder using dust collected from a rotary furnace for producing tungsten powder comprises the following steps: S1. 1.2 tons of dust collecting material and 6 tons of tungsten oxide are mixed with a double cone mixer at a mixing time of 60 minutes and a mixing speed of 8.0 r / min to obtain a mixture of tungsten oxide and dust collecting material; S2. The mixed material is subjected to high-temperature reduction in a reducing atmosphere to obtain tungsten powder; the reduction process is carried out in a rotary furnace, the mixed material feed rate during the reduction process is 260kg / h, the reduction temperature is: the first zone temperature is 770°C, the second zone temperature is 850°C, the third zone temperature is 920°C, the fourth zone temperature is 930°C, the fifth zone temperature is 950°C, and the sixth zone temperature is 970°C; the reducing atmosphere flow rate is 480m 3 / h, the rotating speed of the rotary kiln is 4r / min, and the reducing atmosphere is hydrogen; S3, pass the tungsten powder through an 80-mesh linear sieve to obtain uniform fine-grained tungsten powder, such as Figure 4 As shown, the ground FSSS particle size of the tungsten powder is 0.90±0.05 μm.

[0023] Comparative Example 1 8t of tungsten oxide was reduced at high temperature in a reducing atmosphere to obtain tungsten powder. The reduction process was carried out in a rotary furnace. The feed rate of the mixed material during the reduction process was 110kg / h. The reduction temperatures were: 630℃ for the first zone, 700℃ for the second zone, 750℃ for the third zone, 800℃ for the fourth zone, 900℃ for the fifth zone, and 970℃ for the sixth zone. The reducing atmosphere flow rate was 550m 3 / h, the rotating speed of the rotary kiln is 5r / min, and the reducing atmosphere is hydrogen; the tungsten powder is passed through an 80-mesh linear sieve to obtain uniform fine-grained tungsten powder, and the specific surface area of ​​the tungsten powder is 3.5±0.5㎡ / g by BET.

[0024] The tungsten powder produced in this comparative example is Figure 5 As shown, there is no difference in physical properties and microscopic morphology between the tungsten powder produced in Example 1. However, the reduction temperature of Comparative Example 1 is higher than that of Example 1.

[0025] Comparative Example 2 7.5t of tungsten oxide was reduced at high temperature in a reducing atmosphere to obtain tungsten powder. The reduction process was carried out in a rotary furnace. The feed rate of the mixed material during the reduction process was 129.5kg / h. The reduction temperatures were: 640℃ for the first zone, 700℃ for the second zone, 740℃ for the third zone, 800℃ for the fourth zone, 910℃ for the fifth zone, and 990℃ for the sixth zone. The reducing atmosphere flow rate was 530m 3 / h, the rotating speed of the rotary kiln is 5r / min, and the reducing atmosphere is hydrogen; the tungsten powder is passed through an 80-mesh linear sieve to obtain uniform fine-grained tungsten powder, and the specific surface area of ​​the tungsten powder is 2.5±0.5㎡ / g by BET.

[0026] The tungsten powder produced in this comparative example is Figure 6 As shown, there is no difference in physical properties and microscopic morphology between the tungsten powder produced in comparative example 2 and the tungsten powder produced in example 2. However, the reduction temperature of comparative example 2 is higher than that of example 2.

[0027] Comparative Example 3 7.5t of tungsten oxide was reduced at high temperature in a reducing atmosphere to obtain tungsten powder. The reduction process was carried out in a rotary furnace. The feed rate of the mixed material during the reduction process was 230kg / h. The reduction temperatures were: 640℃ for the first zone, 700℃ for the second zone, 740℃ for the third zone, 800℃ for the fourth zone, 910℃ for the fifth zone, and 990℃ for the sixth zone. The reducing atmosphere flow rate was 500m 3 / h, the rotating speed of the rotary kiln is 5r / min, and the reducing atmosphere is hydrogen; the tungsten powder is passed through an 80-mesh linear sieve to obtain uniform fine-grained tungsten powder, and the ground FSSS particle size of the tungsten powder is 0.80±0.05μm.

[0028] The tungsten powder produced in this comparative example is Figure 7 As shown, there is no difference in physical properties and microscopic morphology between the tungsten powder produced in Example 3. However, the reduction temperature of Comparative Example 3 is higher than that of Example 3.

[0029] Comparative Example 4 7.2t of tungsten oxide was reduced at high temperature in a reducing atmosphere to obtain tungsten powder. The reduction process was carried out in a rotary furnace. The feed rate of the mixed material was 260kg / h. The reduction temperatures were: 800℃ for the first zone, 880℃ for the second zone, 950℃ for the third zone, 960℃ for the fourth zone, 980℃ for the fifth zone, and 1000℃ for the sixth zone. The reducing atmosphere flow rate was 480m 3 / h, the rotating speed of the rotary kiln is 4r / min, and the reducing atmosphere is hydrogen; the tungsten powder is passed through an 80-mesh linear sieve to obtain uniform fine-grained tungsten powder, and the ground FSSS particle size of the tungsten powder is 0.90±0.05μm.

[0030] The tungsten powder produced in this comparative example is Figure 8 As shown, there is no difference in physical properties and microscopic morphology between the tungsten powder produced in Example 4. However, the reduction temperature of Comparative Example 4 is higher than that of Example 4.

[0031] Comparative Example 5 4 tons of dust collecting material and 2 tons of tungsten oxide were mixed with a double cone mixer, the mixing time was 30 minutes, the mixing speed was 6.0 r / min, and a mixture of tungsten oxide and dust collecting material was obtained; the mixture was subjected to high-temperature reduction in a reducing atmosphere to obtain tungsten powder; the reduction process was carried out in a rotary furnace, the feed rate of the mixture during the reduction process was 230 kg / h, and the reduction temperatures were: 750°C for the first zone, 830°C for the second zone, 900°C for the third zone, 910°C for the fourth zone, 930°C for the fifth zone, and 950°C for the sixth zone; the reducing atmosphere flow rate was 500 m 3 / h, the rotating speed of the rotary kiln is 5r / min, and the reducing atmosphere is hydrogen; the product is passed through an 80-mesh linear sieve to obtain a mixture of brown-red powder and black powder, and the mixture is tungsten dioxide and tungsten powder after XRD analysis.

[0032] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A method for preparing fine-grained tungsten powder using dust collected from a rotary furnace for producing tungsten powder, characterized in that: The steps include: S1. Mixing the dust collecting material with tungsten oxide to obtain a mixture of tungsten oxide and the dust collecting material; S2, reducing the mixture at high temperature in a reducing atmosphere to obtain tungsten powder; S3. Sieve the tungsten powder to obtain uniform fine-grained tungsten powder.

2. The method for preparing fine-grained tungsten powder using dust collected from a rotary furnace for producing tungsten powder according to claim 1, characterized in that: In the step S1, the dust collecting material includes tungsten trioxide, intermediate tungsten oxide and incompletely reacted tungsten powder.

3. The method for preparing fine-grained tungsten powder using dust collected from a rotary furnace for producing tungsten powder according to claim 1, characterized in that: The mass ratio of dust collecting material to tungsten oxide is 1:(3~5).

4. The method for preparing fine-grained tungsten powder using dust collected from a rotary furnace for producing tungsten powder according to claim 1, characterized in that: In the step S1, a double cone mixer is used for mixing, the mixing time is 30-60 min, and the mixing speed is 6.0-10.0 r / min.

5. The method for preparing fine-grained tungsten powder using dust collected from a rotary furnace for producing tungsten powder according to claim 1, characterized in that: In step S2, the reduction process is carried out in a rotary kiln.

6. The method for preparing fine-grained tungsten powder using dust collected from a rotary furnace for producing tungsten powder according to claim 1, characterized in that: In step S2, the feed rate of the mixed material during the reduction process is 100-280 kg / h.

7. The method for preparing fine-grained tungsten powder using dust collected from a rotary furnace for producing tungsten powder according to claim 1, characterized in that: In step S2, the reduction temperature is 610-1020°C, and the reduction atmosphere flow rate is 400-550m 3 / h.

8. The method for preparing fine-grained tungsten powder using dust collected from a rotary furnace for producing tungsten powder according to claim 5, characterized in that: In step S2, the rotation speed of the rotary kiln is 3-6 r / min.

9. The method for preparing fine-grained tungsten powder using dust collected from a rotary furnace for producing tungsten powder according to claim 1, characterized in that: In step S2, the reducing atmosphere is hydrogen.

10. The method for preparing fine-grained tungsten powder using dust collected from a rotary furnace for producing tungsten powder according to claim 1, characterized in that: In step S3, the mesh size of the sieve is 80-100 meshes, and the sieve frequency is 30-50 Hz.

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