A method for preparing tungsten carbide powder based on a self-milling process

Abstract

The present application belongs to the technical field of hard alloy material, and relates to a method for preparing tungsten carbide powder based on a self-milling process. The method uses tungsten carbide with different particle sizes as raw material, which is added into a ball mill, and the target tungsten carbide powder is obtained after ball milling and screening. The tungsten carbide raw material is composed of three types of coarse tungsten carbide, fine tungsten carbide and micro tungsten carbide. The ball mill is a closed space, and nitrogen and argon are gradually introduced during the ball milling process until the pressure in the ball mill tank reaches 0.8-1.5 MPa, and the aeration is stopped. The ball mill rotates in the forward and reverse rotation mode alternately. The preparation method utilizes the high hardness and high wear resistance of tungsten carbide, and controls the particle size of tungsten oxide raw material and the rotation mode of the ball mill, etc. parameters, so that the tungsten carbide itself is used as the raw material and the grinding ball, and self-milling crushing is carried out. The method not only reduces the consumption of grinding balls and brings no pollutants, but also greatly improves the grinding efficiency, and is suitable for industrial production.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of hard alloy materials, and particularly relates to a method for preparing tungsten carbide powder based on a self-ball milling process. BACKGROUND

[0002] Tungsten carbide is an important material for preparing hard alloy, and is mainly obtained by carbonizing tungsten powder, and has a sintering method and a casting method. Due to differences in crystal structure, the obtained tungsten carbide has different particle sizes and needs to be further processed. The method for controlling the particle size of tungsten carbide is mainly through subsequent ball milling process.

[0003] At present, the ball milling process includes wet ball milling and dry ball milling. Mainly, the raw material is added to the ball milling device, grinding balls are added, and then some additives are added for ball milling to achieve the desired particle size. For example, Chinese patent 200980144624.6 adopts hard alloy balls with a diameter of 4-6 mm, the positive and negative deviation of the diameter of the alloy ball is ≤0.1 mm, tungsten carbide powder with a diameter of 0.3-0.8 um and drill powder are used, alcohol is used as a grinding medium, and paraffin is used as a forming agent. The ball-material ratio between the hard alloy ball and the tungsten carbide powder and the drill powder is 3:1. The rotating speed of the stirring arm is 100-135 rpm / min, and the ball milling time is 6-8 h. Chinese patent 20101024246975.4 selects a mixture of tungsten carbide powder with a particle size of ≥2.0 um and cobalt powder as raw material, uses alcohol as a ball milling medium, polyethylene glycol as a binder, and adds stearic acid as a dispersant in the ball milling medium, and carries out ball milling through a stirring ball mill. The ball milling parameters of the stirring ball mill are as follows: the ball milling rotating speed is 100-120 rpm, the filling coefficient is 0.5, the solid-liquid volume ratio is 1:1, the diameter of the grinding ball is 6.0 mm±0.2 mm, and the ball-material ratio is 4-5:1. In the above existing method, more than 3 times of grinding balls need to be added, the ball milling efficiency is low, the grinding balls are easy to hide the material and are difficult to clean, and the additives added are easy to bring in foreign matters or pollutants, which affects the product quality. SUMMARY

[0004] In view of the deficiencies of the prior art, the purpose of the present application is to provide a method for preparing tungsten carbide powder based on a self-ball milling process. The preparation method utilizes the characteristics of high hardness and high wear resistance of tungsten carbide itself, controls the particle size of tungsten oxide raw material, uses itself as raw material and grinding ball, and carries out self-ball milling crushing, which not only reduces the consumption of grinding balls, does not bring in pollutants, greatly improves the grinding efficiency, and is suitable for industrial production.

[0005] The present application provides a method for preparing tungsten carbide powder based on a self-ball milling process. Different particle sizes of tungsten carbide are used as raw material, added to the ball mill, and after ball milling and screening, the target tungsten carbide powder can be obtained.

[0006] The raw material of the tungsten carbide is composed of coarse tungsten carbide, fine tungsten carbide and micro tungsten carbide;

[0007] The ball mill is a closed space, and nitrogen and argon are gradually introduced during the ball milling process until the pressure in the tank of the ball mill reaches 0.8-1.5 MPa, and the aeration is stopped.

[0008] The ball mill rotates in the forward and reverse rotation alternately.

[0009] In the technical solution, tungsten carbide is used as the raw material and the grinding ball, and the high hardness and high wear resistance of tungsten carbide are utilized to break the tungsten carbide itself without adding other grinding balls. The ball milling efficiency can be improved by ball milling the tungsten carbide with different particle sizes. The ball milling has a certain pressure by introducing gas, which can protect the silicon carbide and promote grinding while effectively preventing the agglomeration between particles as the particle size of tungsten carbide decreases. The target tungsten carbide powder can be obtained by controlling the rotation speed, rotation mode and grinding time of the ball mill. The method does not need to add grinding balls, and the tungsten carbide is used as both the raw material and the grinding ball, which can not only improve the ball milling efficiency, but also avoid the introduction of foreign matter due to the breakage of the grinding ball, affecting the product quality. In addition, no other grinding balls are used, the grinding machine is easy to clean, and there is no need to worry about the shortage of grinding balls, and the process is more stable. In addition, no other dispersing agent is added in the present application, and the powder dispersion and fluidity can be effectively maintained under the action of pressure and the self-force between the tungsten carbide powders by introducing gas.

[0010] Preferably, in the above technical solution, the three types of coarse tungsten carbide, fine tungsten carbide and micro tungsten carbide are mixed in a mass ratio of 3-5:2-3:1-2. In the technical solution, different particle sizes of tungsten carbide are added at the same time to fully utilize the grinding space and the extrusion grinding effect between different particle sizes, which can greatly improve the grinding efficiency.

[0011] Preferably, in the above technical solution, the particle size of the coarse tungsten carbide is greater than 20 μm.

[0012] Preferably, in the above technical solution, the particle size of the fine tungsten carbide is 11-20 μm.

[0013] Preferably, in the above technical solution, the particle size of the micro tungsten carbide is 5-10 μm.

[0014] Preferably, in the above technical solution, the volume ratio of nitrogen to argon is 2-3:0.3. The purpose of introducing nitrogen and argon in the technical solution is to increase the pressure and protect the tungsten carbide. Since the densities of the two gases are different, the argon will sink to the surface of the tungsten carbide as the gas is added, which can effectively prevent the denaturation of the tungsten carbide.

[0015] Preferably, the ventilation rate is 2-10 L / min.

[0016] Preferably, the size of the ball mill is φ900 mm x 600 mm.

[0017] Preferably, the loading amount of the tungsten carbide is 45-65% of the effective volume of the mill. In general, the loading amount is 30-40% when using the ball milling process. In the present technical solution, the tungsten carbide itself is used as the grinding ball, and each particle size model can be a grinding ball relative to other particle sizes, so the ball milling efficiency is very high, and the loading amount can be increased.

[0018] Preferably, the rotation speed of the ball mill is 20-40 r / min, and the ball milling time is 3-6 h.

[0019] Preferably, the ball milling rotation mode is forward rotation for 0.5-2 h and reverse rotation for 0.1-0.5 h, and the forward rotation and the reverse rotation are alternately performed. Specifically, the forward rotation can be performed for 0.5 h, the reverse rotation can be performed for 0.1 h, then the forward rotation can be continuously performed for 1 h, the reverse rotation can be performed for 0.2 h, and other modes of forward rotation and reverse rotation can be alternately performed.

[0020] Preferably, the oversize after screening is re-placed into the mill for the next round of grinding. In the present technical solution, after obtaining the target tungsten carbide powder, the oversize can be re-placed into the next round of grinding process without waste.

[0021] The beneficial effects of the present application relative to the prior art are as follows:

[0022] The present application utilizes the high hardness and high wear resistance of tungsten carbide itself, and uses the tungsten carbide self-milling and breaking without adding other media and grinding balls. By matching tungsten carbide of different particle sizes for ball milling, the ball milling efficiency is high, and the yield is high. According to the particle size of the target product, the ball mill rotation speed, the rotation mode and the grinding time can be controlled to obtain the target tungsten carbide powder required.

[0023] In the ball milling process, a closed space ball mill is gradually used, nitrogen and argon are introduced, the pressure in the grinding process can be gradually increased, the ball milling can be promoted, and the quality of the tungsten carbide can be effectively ensured by controlling the proportion of the two.

[0024] The present application uses tungsten carbide as a grinding ball, which can effectively avoid the problem of low ball milling efficiency caused by too few grinding balls, has a large loading amount, and has high ball milling efficiency. At the same time, no other substances are added, no pollutants are brought in, and the quality of the obtained tungsten carbide powder is high.

[0025] The present application has a simple process, does not need to use other media, utilizes the force between the particles of tungsten carbide itself, has good dispersibility and flowability, has high yield, and is suitable for industrial production. DETAILED DESCRIPTION

[0026] The above technical features of the present application and the technical features described in detail below (such as the embodiments) can be combined with each other to form new or preferred technical solutions, but the present application is not limited to these embodiments only, and these embodiments do not limit the present application in any way.

[0027] The experimental methods in the following examples are all conventional methods unless otherwise specified. The preparations involved in the following examples are all ordinary commercially available products unless otherwise specified, and can be purchased on the market.

[0028] The present application discloses a method for preparing tungsten carbide powder based on a self-milling process. Different particle sizes of tungsten carbide are used as raw materials, which are added to a ball mill, and the target tungsten carbide powder is obtained after ball milling and screening. The tungsten carbide is composed of three types of coarse tungsten carbide, fine tungsten carbide and micro tungsten carbide. The ball mill is a closed space, and nitrogen and argon are gradually introduced at a speed of 2-10 L / min (volume ratio of 2-3:0.4) during the ball milling process until the pressure in the ball mill tank reaches 0.8-1.5 Mpa, and the aeration is stopped. The ball mill rotates in the forward and reverse directions alternately.

[0029] In this method, different particle sizes of tungsten carbide refer to a mixture of coarse tungsten carbide with a particle size greater than 20 μm, fine tungsten carbide with a particle size of 11-20 μm, and micro tungsten carbide with a particle size of 5-10 μm, which can be mixed in a mass ratio of 3-5:2-3:1-2. In this application, tungsten carbide is used as the grinding ball and raw material, and by controlling the proportion of different tungsten carbides, the space extrusion force between materials is effectively utilized, and the self-milling of tungsten carbide can be realized. The process is stable, and the quality of the obtained product is high.

[0030] The specific steps of the method are as follows: the completely carbonized tungsten carbide raw material is mixed according to the above-mentioned different types and particle size ratios, and is loaded into a ball mill with a size of φ900 mm x 600 mm, and the boat is loaded according to 45-65% of the effective volume of the ball mill. The speed of the ball mill is controlled at 20-40 r / min, and the forward rotation is 0.5-2 h and the reverse rotation is 0.1-0.5 h alternately, and the ball milling is carried out for 3-6 h. At the same time, nitrogen and argon are gradually introduced at a speed of 2-10 L / min (volume ratio of 2-3:0.4) during the ball milling process until the pressure in the ball mill tank reaches 0.8-1.5 Mpa, and the aeration is stopped. Then, according to the required product, the screening is carried out.

[0031] In this method, the tungsten carbide powder has good flowability, and the particle size of the product can be controlled by controlling the loading amount, the forward and reverse rotation speed and the ball milling time. The process is simple, and the quality of the product is controllable.

[0032] The present application will be further described in detail below in combination with specific embodiments:

[0033] Example 1

[0034] A method for preparing tungsten carbide powder based on self-milling process (target product particle size range less than or equal to 3 μm), specifically comprising the following steps:

[0035] The completely carbonized tungsten carbide raw material is mixed in a ratio of 3:2:1 of coarse tungsten carbide, fine tungsten carbide and micro tungsten carbide, the ball mill is a closed space, and the effective volume is 45% of the boat. In the ball milling process, gradually introduce nitrogen and argon (volume ratio of 3:0.4) at a speed of 2L / min until the pressure in the ball mill tank reaches 0.8Mpa, stop aeration, at the same time, control the speed of the ball mill to 20r / min, forward rotation 0.5h, reverse rotation 0.1h, forward rotation 0.6h, reverse rotation 0.3h, forward rotation 1h, reverse rotation 0.5h, total ball milling 3h, and then pass through 3μm screen to obtain tungsten carbide powder with particle size less than or equal to 3μm. The yield of tungsten carbide powder is 78% and the rest angle is 23°.

[0036] Example 2

[0037] A method for preparing tungsten carbide powder based on self-milling process (target product particle size range less than or equal to 3 μm), specifically comprising the following steps:

[0038] The completely carbonized tungsten carbide raw material is mixed in a ratio of 3:2:1 of coarse tungsten carbide, fine tungsten carbide and micro tungsten carbide, the ball mill is a closed space, and the effective volume is 45% of the boat. In the ball milling process, gradually introduce nitrogen and argon (volume ratio of 3:0.4) at a speed of 2-10L / min until the pressure in the ball mill tank reaches 0.8Mpa, stop aeration, at the same time, control the speed of the ball mill to 20r / min, forward rotation 1h, reverse rotation 0.2h, forward rotation 1h, reverse rotation 0.2h, forward rotation 1h, reverse rotation 0.2h, forward rotation 1h, reverse rotation 0.2h, forward rotation 1h, reverse rotation 0.2h, total ball milling 6h, and then pass through 3μm screen to obtain tungsten carbide powder with particle size less than or equal to 3μm. The yield of tungsten carbide powder is 86% and the rest angle is 22°.

[0039] Example 3

[0040] A method for preparing tungsten carbide powder based on self-milling process (target product particle size range less than or equal to 7 μm), specifically comprising the following steps:

[0041] The completely carbonized tungsten carbide raw material is mixed in a ratio of 5:3:2 of coarse tungsten carbide, fine tungsten carbide and micro tungsten carbide, the ball mill is a closed space, and the effective volume is 55% of the tank. Nitrogen and argon are gradually introduced at a speed of 5L / min (volume ratio of 2.5:0.4) during the ball milling process until the pressure in the tank reaches 1.0Mpa, and the gas supply is stopped. At the same time, the rotation speed of the ball mill is controlled at 30r / min, and the positive rotation is 0.5h, the reverse rotation is 0.1h, the positive rotation is 1h, the reverse rotation is 0.3h, the positive rotation is 1.6h, the reverse rotation is 0.5h, and the total ball milling time is 4h. The particle size of the tungsten carbide powder obtained by passing through a 7μm screen is less than or equal to 7μm. The yield of the tungsten carbide powder is 91% and the angle of repose is 26°.

[0042] Example 4

[0043] A method for preparing tungsten carbide powder based on self-milling process (target product particle size range less than or equal to 7μm), specifically comprising the following steps:

[0044] The completely carbonized tungsten carbide raw material is mixed in a ratio of 5:3:2 of coarse tungsten carbide, fine tungsten carbide and micro tungsten carbide, the ball mill is a closed space, and the effective volume is 55% of the tank. Nitrogen and argon are gradually introduced at a speed of 5L / min (volume ratio of 2.5:0.4) during the ball milling process until the pressure in the tank reaches 1.0Mpa, and the gas supply is stopped. At the same time, the rotation speed of the ball mill is controlled at 30r / min, and the positive rotation is 1h, the reverse rotation is 0.2h, the positive rotation is 1h, the reverse rotation is 0.2h, the positive rotation is 1h, the reverse rotation is 0.2h, the positive rotation is 1h, the reverse rotation is 0.2h, the positive rotation is 1h, the reverse rotation is 0.2h, and the total ball milling time is 6h. The particle size of the tungsten carbide powder obtained by passing through a 7μm screen is less than or equal to 7μm. The yield of the tungsten carbide powder is 93% and the angle of repose is 25°.

[0045] Example 5

[0046] A method for preparing tungsten carbide powder based on self-milling process (target product particle size range less than or equal to 10μm), specifically comprising the following steps:

[0047] The completely carbonized tungsten carbide raw material is mixed in a ratio of 4:2:1 of coarse tungsten carbide, fine tungsten carbide and micro tungsten carbide, the ball mill is a closed space, and the effective volume is 65% of the tank. During the ball milling process, nitrogen and argon are gradually introduced at a speed of 10 L / min (volume ratio of 2:0.4) until the pressure in the tank of the ball mill reaches 1.5 Mpa, the aeration is stopped, and the rotation speed of the ball mill is controlled at 40 r / min. The positive rotation is 0.5 h, the reverse rotation is 0.1 h, the positive rotation is 0.6 h, the reverse rotation is 0.3 h, the positive rotation is 1 h, the reverse rotation is 0.5 h, and the total ball milling time is 3 h. The tungsten carbide powder with a particle size of less than or equal to 10 μm is obtained by passing through a 10 μm screen. The yield of the tungsten carbide powder is 95%, and the rest angle is 28°.

[0048] Example 6

[0049] A method for preparing tungsten carbide powder based on a self-milling process (the target product particle size range is less than or equal to 10 μm), specifically comprising the following steps:

[0050] The completely carbonized tungsten carbide raw material is mixed in a ratio of 4:2:1 of coarse tungsten carbide, fine tungsten carbide and micro tungsten carbide, the ball mill is a closed space, and the effective volume is 65% of the tank. During the ball milling process, nitrogen and argon are gradually introduced at a speed of 10 L / min (volume ratio of 2:0.4) until the pressure in the tank of the ball mill reaches 1.5 Mpa, the aeration is stopped, and the rotation speed of the ball mill is controlled at 40 r / min. The positive rotation is 0.5 h, the reverse rotation is 0.1 h, the positive rotation is 0.6 h, the reverse rotation is 0.3 h, the positive rotation is 1 h, the reverse rotation is 0.5 h, and the total ball milling time is 3 h. The tungsten carbide powder with a particle size of less than or equal to 10 μm is obtained by passing through a 10 μm screen. The yield of the tungsten carbide powder is 95%, and the rest angle is 28°.

[0051] Comparative Example 1

[0052] A method for preparing tungsten carbide powder based on a self-milling process, specifically comprising the following steps:

[0053] The completely carbonized tungsten carbide raw material is mixed in a ratio of 4:2:1 of coarse tungsten carbide, fine tungsten carbide and micro tungsten carbide, the ball mill is a closed space, and the effective volume is 65% of the tank. During the ball milling process, nitrogen and argon are gradually introduced at a speed of 10 L / min (volume ratio of 2:0.4) until the pressure in the tank of the ball mill reaches 1.5 Mpa, the aeration is stopped, and the rotation speed of the ball mill is controlled at 40 r / min. The positive rotation is 0.5 h, the reverse rotation is 0.1 h, the positive rotation is 0.6 h, the reverse rotation is 0.3 h, the positive rotation is 1 h, the reverse rotation is 0.5 h, and the total ball milling time is 3 h. The tungsten carbide powder with a particle size of less than or equal to 10 μm is obtained by passing through a 10 μm screen. The yield of the tungsten carbide powder is 95%, and the rest angle is 28°.

[0054] ① The ball mill is a closed space, and the boat is filled according to 45% of the effective volume. Nitrogen and argon are gradually introduced at a speed of 2L / min during the ball milling process (volume ratio is 3:0.4) until the pressure in the ball mill tank reaches 0.8Mpa, stop aeration, at the same time, by controlling the speed of the ball mill to 20r / min, forward rotation 1h, reverse rotation 0.2h, forward rotation 1h, reverse rotation 0.2h, forward rotation 1h, reverse rotation 0.2h, forward rotation 1h, reverse rotation 0.2h, forward rotation 1h, reverse rotation 0.2h, total ball milling 6h, pass through 3μm screen, get tungsten carbide powder with particle size less than or equal to 3μm, by calculation, the yield of tungsten carbide powder is 60%, the angle of repose is 35°;

[0055] ② The ball mill is a closed space, and the boat is filled according to 55% of the effective volume. Nitrogen and argon are gradually introduced at a speed of 5L / min during the ball milling process (volume ratio is 2.5:0.4) until the pressure in the ball mill tank reaches 1.0Mpa, stop aeration, at the same time, by controlling the speed of the ball mill to 30r / min, forward rotation 1h, reverse rotation 0.2h, forward rotation 1h, reverse rotation 0.2h, forward rotation 1h, reverse rotation 0.2h, forward rotation 1h, reverse rotation 0.2h, forward rotation 1h, reverse rotation 0.2h, total ball milling 6h, pass through 7μm screen, get tungsten carbide powder with particle size less than or equal to 7μm, by calculation, the yield of tungsten carbide powder is 70%, the angle of repose is 36°;

[0056] ③ The ball mill is a closed space, and the boat is filled according to 65% of the effective volume. Nitrogen and argon are gradually introduced at a speed of 10L / min during the ball milling process (volume ratio is 2:0.4) until the pressure in the ball mill tank reaches 1.5Mpa, stop aeration, at the same time, by controlling the speed of the ball mill to 40r / min, forward rotation 1h, reverse rotation 0.2h, forward rotation 1h, reverse rotation 0.2h, forward rotation 1h, reverse rotation 0.2h, forward rotation 1h, reverse rotation 0.2h, forward rotation 1h, reverse rotation 0.2h, total ball milling 6h, pass through 10μm screen, get tungsten carbide powder with particle size less than or equal to 10μm, by calculation, the yield of tungsten carbide powder is 75%, the angle of repose is 37°.

[0057] Comparative Example 2

[0058] A method for preparing tungsten carbide powder based on self-ball milling process, specifically comprising the following steps:

[0059] The completely carbonized tungsten carbide raw material, the fine tungsten carbide after screening (particle size is 11-20μm):

[0060] ① The ball mill is a closed space, and the boat is filled according to 45% of the effective volume. Nitrogen and argon are gradually introduced at a speed of 2L / mincm 3The speed of nitrogen and argon (volume ratio of 3:0.4) is gradually increased to 10 L / min until the pressure in the tank of the ball mill reaches 1.5 Mpa, the ventilation is stopped, and the rotation speed of the ball mill is controlled at 40 r / min. The positive rotation is 1 h, the reverse rotation is 0.2 h, the positive rotation is 1 h, the reverse rotation is 0.2 h, the positive rotation is 1 h, the reverse rotation is 0.2 h, the positive rotation is 1 h, the reverse rotation is 0.2 h, the positive rotation is 1 h, the reverse rotation is 0.2 h, and the total ball milling time is 6 h. The tungsten carbide powder with a particle size of less than or equal to 10 μm is obtained by passing through a 10 μm screen. The yield of the tungsten carbide powder is 76%, and the angle of repose is 35°.

[0061] The ball mill is a closed space, and the boat is filled according to 55% of the effective volume. The speed of nitrogen and argon (volume ratio of 2.5:0.4) is gradually increased to 5 L / min during the ball milling process until the pressure in the tank of the ball mill reaches 1.0 Mpa. The ventilation is stopped, and the rotation speed of the ball mill is controlled at 30 r / min. The positive rotation is 1 h, the reverse rotation is 0.2 h, the positive rotation is 1 h, the reverse rotation is 0.2 h, the positive rotation is 1 h, the reverse rotation is 0.2 h, the positive rotation is 1 h, the reverse rotation is 0.2 h, the positive rotation is 1 h, the reverse rotation is 0.2 h, and the total ball milling time is 6 h. The tungsten carbide powder with a particle size of less than or equal to 7 μm is obtained by passing through a 7 μm screen. The yield of the tungsten carbide powder is 73%, and the angle of repose is 34°.

[0062] The ball mill is a closed space, and the boat is filled according to 65% of the effective volume. The speed of nitrogen and argon (volume ratio of 2:0.4) is gradually increased to 10 L / min during the ball milling process until the pressure in the tank of the ball mill reaches 1.5 Mpa. The ventilation is stopped, and the rotation speed of the ball mill is controlled at 40 r / min. The positive rotation is 1 h, the reverse rotation is 0.2 h, the positive rotation is 1 h, the reverse rotation is 0.2 h, the positive rotation is 1 h, the reverse rotation is 0.2 h, the positive rotation is 1 h, the reverse rotation is 0.2 h, the positive rotation is 1 h, the reverse rotation is 0.2 h, and the total ball milling time is 6 h. The tungsten carbide powder with a particle size of less than or equal to 10 μm is obtained by passing through a 10 μm screen. The yield of the tungsten carbide powder is 76%, and the angle of repose is 35°.

[0063] Comparative Example 3

[0064] A method for preparing tungsten carbide powder based on a self-ball milling process, specifically comprising the following steps:

[0065] The completely carbonized tungsten carbide raw material is sieved into micro-tungsten carbide (particle size of 5-10 μm):

[0066] ① The ball mill is a closed space. The boat is filled with 45% of the effective volume. During the ball milling process, nitrogen and argon (volume ratio of 3:0.4) are gradually introduced at a rate of 2L / min until the pressure inside the ball mill reaches 0.8Mpa. Then the gas supply is stopped. At the same time, the speed of the ball mill is controlled at 20r / min. The cycle is: forward rotation for 1h, reverse rotation for 0.2h, forward rotation for 1h, reverse rotation for 0.2h, forward rotation for 1h, reverse rotation for 0.2h, forward rotation for 1h, reverse rotation for 0.2h, forward rotation for 1h, reverse rotation for 0.2h, for a total of 6h of ball milling. The powder is then passed through a 3μm sieve to obtain tungsten carbide powder with a particle size of less than or equal to 3μm. The yield of tungsten carbide powder is calculated to be 68%, and the angle of repose is 32°.

[0067] ② The ball mill is a closed space. The ball mill is filled with 55% of its effective volume. During the ball milling process, nitrogen and argon (volume ratio of 2.5:0.4) are gradually introduced at a rate of 5 L / min until the pressure inside the ball mill reaches 1.0 MPa. Then, the gas supply is stopped. At the same time, the rotation speed of the ball mill is controlled at 30 r / min. The rotation is repeated 1 hour in the forward direction and 0.2 hours in the reverse direction. The total ball milling time is 6 hours. The powder is then passed through a 7 μm sieve to obtain tungsten carbide powder with a particle size of less than or equal to 7 μm. The yield of tungsten carbide powder is calculated to be 77%, and the angle of repose is 34°.

[0068] Comparative Example 4

[0069] A method for preparing tungsten carbide powder based on a self-ball milling process specifically includes the following steps:

[0070] Fully carbonized tungsten carbide raw materials are mixed at a mass ratio of coarse tungsten carbide (particle size greater than 20 μm) to fine tungsten carbide (particle size 11-20 μm) of 3:2.

[0071] ① The ball mill is a closed space. The boat is filled to 45% of its effective volume, and during the ball milling process, the water gradually increases at a rate of 2...

[0072] Nitrogen and argon gas (volume ratio 3:0.4) were introduced at a rate of L / min until the pressure inside the ball mill tank reached 0.8 MPa. Then, the gas supply was stopped. At the same time, the ball mill speed was controlled at 20 r / min, rotating forward for 1 h, then in reverse for 0.2 h, then rotating forward for 1 h, then in reverse for 0.2 h, then rotating forward for 1 h, then in reverse for 0.2 h, then rotating forward for 1 h, then in reverse for 0.2 h, then rotating forward for 1 h, then in reverse for 0.2 h, for a total of 6 h of ball milling. The powder was then passed through a 3 μm sieve to obtain tungsten carbide powder with a particle size of less than or equal to 3 μm. The yield of tungsten carbide powder was calculated to be 66%, and the angle of repose was 28°.

[0073] ② The ball mill is a closed space, and the effective volume is 55% of the tank. Nitrogen and argon are gradually introduced at a rate of 5L / min (volume ratio of 2.5:0.4) during the ball milling process until the pressure in the tank reaches 1.0Mpa. Stop aeration, and control the speed of the ball mill at 30r / min. Positive rotation for 1h, reverse rotation for 0.2h, positive rotation for 1h, reverse rotation for 0.2h, positive rotation for 1h, reverse rotation for 0.2h, positive rotation for 1h, reverse rotation for 0.2h, positive rotation for 1h, reverse rotation for 0.2h, total ball milling for 6h, and then pass through a 7μm sieve to obtain tungsten carbide powder with a particle size of less than or equal to 7μm. The yield of tungsten carbide powder is 73%, and the angle of repose is 30°.

[0074] ③ The ball mill is a closed space, and the effective volume is 65% of the tank. Nitrogen and argon are gradually introduced at a rate of 10L / min (volume ratio of 2:0.4) during the ball milling process until the pressure in the tank reaches 1.5Mpa. Stop aeration, and control the speed of the ball mill at 40r / min. Positive rotation for 1h, reverse rotation for 0.2h, positive rotation for 1h, reverse rotation for 0.2h, positive rotation for 1h, reverse rotation for 0.2h, positive rotation for 1h, reverse rotation for 0.2h, positive rotation for 1h, reverse rotation for 0.2h, total ball milling for 6h, and then pass through a 10μm sieve to obtain tungsten carbide powder with a particle size of less than or equal to 10μm. The yield of tungsten carbide powder is 81%, and the angle of repose is 29°.

[0075] Comparative Example 5

[0076] A method for preparing tungsten carbide powder based on a self-ball milling process, specifically comprising the following steps:

[0077] The completely carbonized tungsten carbide raw material is mixed with coarse tungsten carbide (particle size greater than 20μm) and micro tungsten carbide (particle size of 5-10μm) at a mass ratio of 3:1:

[0078] ① The ball mill is a closed space, and the effective volume is 45% of the tank. Nitrogen and argon are gradually introduced at a rate of 2L / min (volume ratio of 3:0.4) during the ball milling process until the pressure in the tank reaches 0.8Mpa. Stop aeration, and control the speed of the ball mill at 20r / min. Positive rotation for 1h, reverse rotation for 0.2h, positive rotation for 1h, reverse rotation for 0.2h, positive rotation for 1h, reverse rotation for 0.2h, positive rotation for 1h, reverse rotation for 0.2h, positive rotation for 1h, reverse rotation for 0.2h, total ball milling for 6h, and then pass through a 3μm sieve to obtain tungsten carbide powder with a particle size of less than or equal to 3μm. The yield of tungsten carbide powder is 64%, and the angle of repose is 31°.

[0079] ② The ball mill is a closed space, and the effective volume is 55% of the tank. Nitrogen and argon are gradually introduced at a speed of 5L / min (volume ratio of 2.5:0.4) during the ball milling process until the pressure in the tank reaches 1.0Mpa. Stop aeration, and control the speed of the ball mill at 30r / min. Positive rotation for 1h, reverse rotation for 0.2h, positive rotation for 1h, reverse rotation for 0.2h, positive rotation for 1h, reverse rotation for 0.2h, positive rotation for 1h, reverse rotation for 0.2h, positive rotation for 1h, and reverse rotation for 0.2h. The total ball milling time is 6h. The obtained tungsten carbide powder with a particle size of less than or equal to 7μm is sieved through a 7μm sieve. The yield of the tungsten carbide powder is 71%, and the angle of repose is 32°.

[0080] ③ The ball mill is a closed space, and the effective volume is 65% of the tank. Nitrogen and argon are gradually introduced at a speed of 10L / min (volume ratio of 2:0.4) during the ball milling process until the pressure in the tank reaches 1.5Mpa. Stop aeration, and control the speed of the ball mill at 40r / min. Positive rotation for 1h, reverse rotation for 0.2h, positive rotation for 1h, reverse rotation for 0.2h, positive rotation for 1h, reverse rotation for 0.2h, positive rotation for 1h, reverse rotation for 0.2h, positive rotation for 1h, and reverse rotation for 0.2h. The total ball milling time is 6h. The obtained tungsten carbide powder with a particle size of less than or equal to 10μm is sieved through a 10μm sieve. The yield of the tungsten carbide powder is 78%.

[0081] Comparative Example 6

[0082] A method for preparing tungsten carbide powder based on a self-ball milling process, specifically comprising the following steps:

[0083] The completely carbonized tungsten carbide raw material is mixed with coarse tungsten carbide (particle size of 11-20μm) and fine tungsten carbide (particle size of 5-10μm) at a mass ratio of 2:1:

[0084] ① The ball mill is a closed space, and the effective volume is 45% of the tank. Nitrogen and argon are gradually introduced at a speed of 2L / min (volume ratio of 3:0.4) during the ball milling process until the pressure in the tank reaches 0.8Mpa. Stop aeration, and control the speed of the ball mill at 20r / min. Positive rotation for 1h, reverse rotation for 0.2h, positive rotation for 1h, reverse rotation for 0.2h, positive rotation for 1h, reverse rotation for 0.2h, positive rotation for 1h, reverse rotation for 0.2h, positive rotation for 1h, and reverse rotation for 0.2h. The total ball milling time is 6h. The obtained tungsten carbide powder with a particle size of less than or equal to 3μm is sieved through a 3μm sieve. The yield of the tungsten carbide powder is 67%, and the angle of repose is 27°.

[0085] The ball mill is a closed space, and the effective volume is 55% of the tank. Nitrogen and argon are gradually introduced at a speed of 5 L / min (volume ratio of 2.5:0.4) during the ball milling process until the pressure in the tank reaches 1.0 Mpa. Stop aeration, and control the speed of the ball mill at 30 r / min. Positive rotation for 1 h, reverse rotation for 0.2 h, positive rotation for 1 h, reverse rotation for 0.2 h, positive rotation for 1 h, reverse rotation for 0.2 h, positive rotation for 1 h, reverse rotation for 0.2 h, positive rotation for 1 h, and reverse rotation for 0.2 h. The total ball milling time is 6 h. The tungsten carbide powder with a particle size of less than or equal to 7 μm is obtained by passing through a 7 μm screen. The yield of the tungsten carbide powder is 75%, and the angle of repose is 28°.

[0086] The ball mill is a closed space, and the effective volume is 65% of the tank. Nitrogen and argon are gradually introduced at a speed of 10 L / min (volume ratio of 2:0.4) during the ball milling process until the pressure in the tank reaches 1.5 Mpa. Stop aeration, and control the speed of the ball mill at 40 r / min. Positive rotation for 1 h, reverse rotation for 0.2 h, positive rotation for 1 h, reverse rotation for 0.2 h, positive rotation for 1 h, reverse rotation for 0.2 h, positive rotation for 1 h, reverse rotation for 0.2 h, positive rotation for 1 h, and reverse rotation for 0.2 h. The total ball milling time is 6 h. The tungsten carbide powder with a particle size of less than or equal to 10 μm is obtained by passing through a 10 μm screen. The yield of the tungsten carbide powder is 84%, and the angle of repose is 29°.

[0087] Comparative Example 7

[0088] A method for preparing tungsten carbide powder based on a self-ball milling process (the particle size range of the target product is less than or equal to 3 μm), specifically including the following steps:

[0089] The completely carbonized tungsten carbide raw material is mixed in a ratio of 3:2:1 of coarse tungsten carbide, fine tungsten carbide, and micro tungsten carbide. The ball mill is a closed space, and the effective volume is 45% of the tank. The speed of the ball mill is controlled at 20 r / min. Positive rotation for 1 h, reverse rotation for 0.2 h, positive rotation for 1 h, reverse rotation for 0.2 h, positive rotation for 1 h, reverse rotation for 0.2 h, positive rotation for 1 h, reverse rotation for 0.2 h, positive rotation for 1 h, and reverse rotation for 0.2 h. The total ball milling time is 6 h. The tungsten carbide powder with a particle size of less than or equal to 3 μm is obtained by passing through a 3 μm screen. The yield of the tungsten carbide powder is 61%, and the angle of repose is 38°.

[0090] Comparative Example 8

[0091] A method for preparing tungsten carbide powder based on a self-ball milling process (the particle size range of the target product is less than or equal to 3 μm), specifically including the following steps:

[0092] The completely carbonized tungsten carbide raw material is mixed in a ratio of 3:2:1 of coarse tungsten carbide, fine tungsten carbide and micro tungsten carbide, the ball mill is a closed space, and the ball mill is filled to 45% of the effective volume. Nitrogen and argon (volume ratio of 3:0.4) are gradually introduced at a speed of 2L / min during the ball milling process until the pressure in the ball mill tank reaches 0.8Mpa, the aeration is stopped, and the speed of the ball mill is controlled at 20r / min. The positive rotation is 3h, and the total ball milling time is 3h. The tungsten carbide powder with a particle size of less than or equal to 3μm is obtained by passing through a 3μm screen. The yield of the tungsten carbide powder is 65%, and the angle of repose is 33°.

[0093] Comparative Example 9

[0094] A method for preparing tungsten carbide powder based on a self-ball milling process (the particle size range of the target product is less than or equal to 3μm), specifically comprising the following steps:

[0095] The completely carbonized tungsten carbide raw material is mixed in a ratio of 3:2:1 of coarse tungsten carbide, fine tungsten carbide and micro tungsten carbide, the ball mill is a closed space, and the ball mill is filled to 45% of the effective volume. Nitrogen and argon (volume ratio of 3:0.4) are gradually introduced at a speed of 2L / min during the ball milling process until the pressure in the ball mill tank reaches 0.8Mpa, the aeration is stopped, and the speed of the ball mill is controlled at 20r / min. The positive rotation is 3h, and the total ball milling time is 3h. The tungsten carbide powder with a particle size of less than or equal to 3μm is obtained by passing through a 3μm screen. The yield of the tungsten carbide powder is 65%, and the angle of repose is 33°.

[0096] From the results of Examples 1-6, it can be seen that by ball milling tungsten carbide of different particle sizes, the ball milling efficiency is high, the yield is high, the flowability is good, the angle of repose is small, and the desired tungsten carbide powder can be obtained by appropriately controlling the speed of the ball mill, aeration and pressurization, rotation mode and milling time according to the particle size of the target product. From the results of Comparative Examples 1-9, it can be seen that the ball milling yield is lower when larger, finer or smaller tungsten carbide is used alone or in combination. The ball milling yield and the angle of repose are both poor when there is no aeration and pressurization, indicating that pressurization is also beneficial to grinding and can promote flowability. The yield is also relatively low when only positive rotation is used, indicating that the grinding efficiency of single-direction ball milling is lower than that of two-way alternating grinding.

[0097] In summary, the preparation method of the application has simple process, only by controlling the particle size of tungsten oxide raw material, ventilation pressure, ball mill rotation mode and other parameters, using itself as raw material and grinding ball, self-ball milling crushing is carried out, so that the grinding ball consumption is reduced, other media is not needed, no pollutants are brought in, the grinding efficiency is greatly improved, and the method is suitable for industrial production.

[0098] Finally, it should be emphasized that the above only describes the preferred embodiments of the present application and is not intended to limit the present application. For those skilled in the art, the present application can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for producing tungsten carbide powder based on a self-milling process, characterized in that, The tungsten carbide powder is obtained by adding tungsten carbide with different particle sizes into a ball mill, ball milling and screening. The tungsten carbide raw material is composed of coarse tungsten carbide, fine tungsten carbide and micro tungsten carbide; the mass ratio of the coarse tungsten carbide, fine tungsten carbide and micro tungsten carbide is 3-5:2-3:1-2; the particle size of the coarse tungsten carbide is greater than 20 μm; the particle size of the fine tungsten carbide is 11-20 μm; the particle size of the micro tungsten carbide is 5-10 μm; The ball mill is a closed space, and nitrogen and argon are gradually introduced during the ball milling process until the pressure in the ball mill tank reaches 0.8-1.5 Mpa, and the aeration is stopped; the volume ratio of nitrogen to argon is 2-3:0.4; The ball mill rotates in the forward rotation and reverse rotation alternately.

2. The method of claim 1, wherein the self-milling process is carried out in a ball mill. The aeration speed is 2-10 L / min.

3. The method of claim 1, wherein the self-milling process is carried out in a ball mill. The size of the ball mill is φ900 mm×600 mm.

4. The method of claim 1, wherein the self-milling process is carried out in a ball mill. The tungsten carbide loading amount is 45-65% of the effective volume of the mill.

5. The method of claim 1, wherein the self-milling process is carried out in a ball mill. The rotation speed of the ball mill is 20-40 r / min, and the ball milling time is 3-6 h.

6. The method of claim 1, wherein the self-milling process is carried out in a ball mill. The ball mill rotates in the forward rotation for 0.5-2 h, and in the reverse rotation for 0.1-0.5 h, and the rotation is alternated.

7. The method of claim 1, wherein the self-milling process is carried out in a ball mill. The oversize after screening is put back into the mill for the next round of grinding.