A ball milling method of electrolytically treated tungsten-containing cemented carbide

Abstract

The application discloses a ball milling method for electrolytically treated tungsten-containing hard alloy, and aims to solve the problems of large dust in dry ball milling process and large difference in physical and chemical indexes of recycled tungsten carbide powder. The ball milling method comprises the following steps: washing electrolytically treated tungsten-containing hard alloy blocks in pure water, then putting the washed tungsten-containing hard alloy blocks into a ball mill for wet ball milling, drying, and obtaining coarse tungsten carbide powder; reducing the coarse tungsten carbide powder at high temperature in an inert atmosphere; and airflow milling the high-temperature reduced coarse tungsten carbide powder to obtain tungsten carbide powder. The ball milling method for electrolytically treated tungsten-containing hard alloy provided by the application reduces the dust generation in the ball milling process by adopting the wet ball milling technology, combining with the optimized ball-to-material ratio, ball milling speed, ball milling time and solid content, and improves the working environment on site. By controlling the drying temperature, time and water content, and optimizing the reduction and airflow milling steps, the final product can have high purity, fine particle size and uniform particle size distribution, and the quality of the product is improved.

Description

Technical Field

[0001] This invention belongs to the technical field of cemented carbide recycling, and particularly relates to a ball milling method for tungsten-containing cemented carbide that has undergone electrolytic treatment. Background Technology

[0002] Current methods for recycling tungsten carbide blocks mainly include zinc melting, mechanical crushing, electrochemical methods, oxidation, and acid leaching. Among these methods, electrochemical methods are widely used due to their relative environmental friendliness and high recycling efficiency. However, existing electrochemical methods primarily rely on dry grinding, which generates large amounts of dust during on-site operation, resulting in an extremely harsh working environment and potential product contamination.

[0003] In dry grinding, the abrasive and grinding chips are in direct contact, and the chips are constantly impacted and sheared within the high-speed rotating grinding disc, generating a large amount of fine dust. This dust not only poses a threat to the health of operators but may also enter the equipment, affecting its normal operation. Furthermore, the dust's emission can pollute the surrounding environment, increasing the difficulty of subsequent treatment.

[0004] To address the problems associated with dry milling, some researchers have attempted to use wet milling. Wet milling reduces dust generation by adding appropriate amounts of liquid, such as water or oil, to the abrasive. However, most existing wet milling methods require the addition of additives, which may affect the purity of the product, thereby reducing its quality.

[0005] While existing technologies offer solutions to the problems associated with dry milling, several technical limitations remain. For instance, some wet milling methods, though reducing dust generation, may introduce additives that could negatively impact product performance. Furthermore, current methods still require improvement in terms of processing efficiency, energy consumption, and equipment lifespan. Summary of the Invention

[0006] The purpose of this invention is to overcome the above-mentioned shortcomings and provide a ball milling method for electrolytically treated tungsten-containing cemented carbide.

[0007] A ball milling method for electrolytically treated tungsten-containing cemented carbide, characterized by comprising the following steps:

[0008] The tungsten-containing cemented carbide block was washed in pure water, and then the washed tungsten-containing cemented carbide block was put into a ball mill for wet ball milling and drying to obtain coarse tungsten carbide powder.

[0009] The crude tungsten carbide powder was reduced at high temperature in an inert atmosphere;

[0010] The crude tungsten carbide powder after high-temperature reduction is subjected to air jet milling to obtain tungsten carbide powder.

[0011] By adopting the above technical solution, through the steps of wet ball milling, high-temperature reduction and air jet milling, tungsten-containing cemented carbide blocks can be effectively processed and recycled, improving ball milling efficiency, increasing the service life of the ball mill, avoiding dust pollution during the ball milling process, improving the on-site working environment, and increasing the recovery rate of cemented carbide.

[0012] Furthermore, in the wet ball milling step, the ball-to-material ratio is 1:1 to 1.5:1, the ball milling speed is 25 r / min to 30 r / min, the ball milling time is 1.5 h to 2 h, and the solid content is 85 wt% to 90 wt%.

[0013] By adopting the above technical solutions, and by precisely controlling the ball-to-material ratio, ball milling speed, ball milling time, and solid content, the ball milling process can be optimized, ball milling efficiency can be improved, and the particle size distribution of the powder can be guaranteed, thereby improving the quality of the product.

[0014] Furthermore, the particle size of the coarse tungsten carbide powder can pass through a 100-mesh sieve.

[0015] By adopting the above technical solution, coarse tungsten carbide powder in this particle size range is beneficial to subsequent high-temperature reduction and air jet milling steps, which can improve reduction efficiency and grinding efficiency, while ensuring that the particle size of the final product meets the requirements.

[0016] Furthermore, the drying temperature is 110℃~120℃, the drying time is 4h~5h, and the moisture content of the dried crude tungsten carbide powder is 0.1wt%~0.2wt%.

[0017] By adopting the above technical solution, appropriate drying temperature and time can effectively remove moisture from the powder, ensuring that the moisture content of the powder is within a suitable range, which is beneficial to subsequent reduction and grinding steps.

[0018] Furthermore, the inert atmosphere is a hydrogen atmosphere; in the high-temperature reduction step, the inlet flow rate is 0.1 m³ / s. 3 / h~0.2m 3 / h, pressure 5KPa~30KPa, reduction temperature 1000℃~1350℃, reduction time 0.5h~1h.

[0019] By adopting the above technical solution and using hydrogen as an inert atmosphere, some of the oxidized tungsten powder can be effectively reduced. At the same time, by controlling the gas flow rate, pressure, reduction temperature and time, the reduction process can be optimized, the reduction efficiency can be improved, and the quality of the product can be guaranteed.

[0020] Furthermore, in the air jet milling step, nitrogen and compressed air are introduced, with a nitrogen to compressed air volume ratio of 8:1 to 10:1.

[0021] By adopting the above technical solution and controlling the volume ratio of nitrogen and compressed air, the air jet mill process can be optimized, the grinding efficiency can be improved, and the particle size of the final product can be guaranteed to meet the requirements.

[0022] Furthermore, in the air jet milling step, the pressure is 0.8MPa to 1.2MPa, and the air jet milling time is 2h to 3h.

[0023] By adopting the above technical solutions, appropriate airflow mill pressure and time can effectively control the grinding process, improve grinding efficiency, and ensure that the particle size of the final product meets the requirements.

[0024] Furthermore, in the air jet milling step, the particle size of the tungsten carbide powder is 1.2 μm to 4.0 μm.

[0025] By adopting the above technical solution, tungsten carbide powder in this particle size range is beneficial for subsequent applications, can improve product performance, and meet specific needs.

[0026] Secondly, a tungsten carbide adopts the following technical solution:

[0027] A type of tungsten carbide, prepared by ball milling of a tungsten-containing cemented carbide block as described in any of the preceding claims.

[0028] By adopting the above technical solution, the tungsten carbide produced by this method has high purity, fine particle size and uniform particle size distribution, which is beneficial for subsequent applications and improves product performance.

[0029] Furthermore, the tungsten carbide has ≤0.07wt% free carbon, ≤0.2wt% oxygen content, and <0.5wt% total content of Co, Ni, Fe, and Ti.

[0030] By adopting the above technical solution, the tungsten carbide has extremely low free carbon and oxygen content and total content of Co, Ni, Fe and Ti, which is beneficial to improving product performance and meeting high application requirements.

[0031] The beneficial effects of this invention are:

[0032] This invention provides a ball milling method for electrolytically treated tungsten-containing cemented carbide. By employing wet ball milling technology and optimizing the ball-to-material ratio, milling speed, milling time, and solid content, ball milling efficiency can be significantly improved, accelerating production speed. Compared to dry milling, wet ball milling reduces wear on the ball mill, extends equipment lifespan, and lowers maintenance costs. Wet ball milling also reduces dust generation during the milling process, thereby improving the working environment and reducing health risks for operators. By precisely controlling milling and subsequent processing parameters, the recovery rate of cemented carbide can be improved, reducing resource waste. By controlling drying temperature, time, and moisture content, and optimizing reduction and air jet milling steps, the final product can be guaranteed to have high purity, fine particle size, and uniform particle size distribution, improving product quality.

[0033] The present invention provides a tungsten carbide with extremely low free carbon and oxygen content and impurity content such as Co, Ni, Fe, and Ti, which is beneficial to improving product performance and meeting the high requirements of applications. Detailed Implementation

[0034] The following detailed description, in conjunction with embodiments, provides a method for ball milling tungsten-containing cemented carbide after electrolytic treatment according to the present invention. For the sake of simplicity, this document cannot exhaustively list all alternative technical features and embodiments included in the present invention. Therefore, those skilled in the art should understand that any technical feature and embodiment within this embodiment does not limit the scope of protection of the present invention, which includes all alternative technical features and embodiments adopted by those skilled in the art without inventive effort. Specifically, any embodiment obtained by replacing any technical feature in the present invention or by combining any two or more technical features provided by the present invention should be within the scope of protection of the present invention.

[0035] Unless otherwise specified in the embodiments, the techniques and conditions described in the literature in this field or the product instructions shall be followed. If the manufacturers of the reagents or instruments used are not specified, they are all conventional products that can be purchased commercially.

[0036] Example

[0037] Example 1

[0038] Example 1 provides a ball milling method for electrolytically treated tungsten-containing cemented carbide, comprising the following steps:

[0039] Wet ball milling: The recycled tungsten-containing cemented carbide blocks that have been cleaned after electrolysis are used as raw materials and ball milled using a conventional ball mill. The ball milling equipment is a closed equipment with a ball-to-material ratio of 1:1, a ball milling speed of 25 r / min, a ball milling time of 2 h, a solid content of 90 wt%, and a particle size of ≤125 μm for the coarse tungsten carbide powder after wet ball milling.

[0040] Drying: Vacuum drying equipment was used to remove the moisture content from the crude tungsten carbide powder. The drying temperature was 110℃ and the drying time was 5h. The moisture content of the dried crude tungsten carbide powder was 0.1wt%.

[0041] High-temperature reduction: A rotary reduction furnace is used to reduce the crude tungsten carbide powder. Hydrogen gas is used to reduce some of the oxidized tungsten powder, with an inlet flow rate of 0.2 m³ / s. 3 / h, pressure of 30KPa, reduction temperature of 1350℃, reduction time of 0.5h;

[0042] Airflow milling: The crude tungsten carbide powder after high-temperature reduction is subjected to airflow milling. Airflow milling includes two processes: ball milling and sorting. Nitrogen and compressed air are introduced into the ball milling equipment. The ratio of nitrogen to compressed air is 10:1, the pressure is 1.2 MPa, and the airflow milling time is 2 hours. After the airflow milling step is completed, tungsten carbide powder is obtained.

[0043] Example 1 provides a tungsten carbide powder with an average particle size of 1.5 μm, a free carbon content of 0.04%, an oxygen content of 0.1%, and a total content of Co, Ni, Fe, and Ti of 0.4%.

[0044] Example 2

[0045] Example 2 provides a ball milling method for electrolytically treated tungsten-containing cemented carbide, comprising the following steps:

[0046] Wet ball milling: The recycled tungsten-containing cemented carbide blocks, which have been cleaned after electrolysis, are used as raw materials and ball milled using a conventional ball mill. The ball milling equipment is a closed system with a ball-to-material ratio of 1.5:1, a ball milling speed of 30 r / min, a ball milling time of 1.5 h, a solid content of 85 wt%, and a particle size of ≤150 μm for the coarse tungsten carbide powder after wet ball milling.

[0047] Drying: Vacuum drying equipment was used to remove the moisture content from the crude tungsten carbide powder. The drying temperature was 120℃ and the drying time was 4 hours. The moisture content of the dried crude tungsten carbide powder was 0.2wt%.

[0048] High-temperature reduction: A rotary reduction furnace is used to reduce the crude tungsten carbide powder. Hydrogen gas is used to reduce some of the oxidized tungsten powder, with an inlet flow rate of 0.1 m³ / s. 3 / h, pressure of 5KPa, reduction temperature of 1000℃, reduction time of 1h;

[0049] Airflow milling: The crude tungsten carbide powder after high-temperature reduction is subjected to airflow milling. Airflow milling includes two processes: ball milling and sorting. Nitrogen and compressed air are introduced into the ball milling equipment, with a nitrogen:compressed air ratio of 8:1 and a pressure of 0.8 MPa. The airflow milling time is 3 hours. After the airflow milling step is completed, tungsten carbide powder is obtained.

[0050] Example 2 provides a tungsten carbide powder with an average particle size of 1.2 μm, a free carbon content of 0.05%, an oxygen content of 0.15%, and a total content of Co, Ni, Fe, and Ti of 0.5%.

[0051] Example 3

[0052] Example 3 provides a ball milling method for electrolytically treated tungsten-containing cemented carbide, comprising the following steps:

[0053] Wet ball milling: The recycled tungsten-containing cemented carbide blocks, which have been cleaned after electrolysis, are used as raw materials and ball milled using a conventional ball mill. The ball milling equipment is a closed system with a ball-to-material ratio of 1.3:1, a ball milling speed of 28 r / min, a ball milling time of 2 h, a solid content of 90 wt%, and a particle size of ≤135 μm for the coarse tungsten carbide powder after wet ball milling.

[0054] Drying: The moisture content of the crude tungsten carbide powder was removed using a vacuum drying device at a temperature of 115℃ for 4.5 hours. The moisture content of the dried crude tungsten carbide powder was 0.12 wt%.

[0055] High-temperature reduction: A rotary reduction furnace is used to reduce the crude tungsten carbide powder. Hydrogen gas is used to reduce some of the oxidized tungsten powder, with an inlet flow rate of 0.15 m³ / h. 3 / h, pressure of 15KPa, reduction temperature of 1250℃, reduction time of 1h;

[0056] Air jet milling: The crude tungsten carbide powder after high-temperature reduction is subjected to air jet milling. Air jet milling includes two processes: ball milling and sorting. Nitrogen and compressed air are introduced into the ball milling equipment. The ratio of nitrogen to compressed air is 9:1, the pressure is 1.0 MPa, and the air jet milling time is 2.5 hours. After the air jet milling step is completed, tungsten carbide powder is obtained.

[0057] Example 3 provides a tungsten carbide powder with an average particle size of 1.2 μm, a free carbon content of 0.03%, an oxygen content of 0.12%, and a total content of Co, Ni, Fe, and Ti of 0.35%.

[0058] Comparative Example

[0059] Comparative Example 1

[0060] Comparative Example 1 provides a ball milling method for electrolytically treated tungsten-containing cemented carbide. The difference between this method and Example 3 is that it uses dry ball milling, as detailed below:

[0061] Comparative Example 1 provides a ball milling method for electrolytically treated tungsten-containing cemented carbide, comprising the following steps:

[0062] Dry ball milling: The recycled tungsten carbide blocks that have been cleaned after electrolysis are used as raw materials and ball milled using a conventional ball mill. The ball-to-material ratio is 1.3:1, the ball milling speed is 28 r / min, and the ball milling time is 2 h. The particle size of the coarse tungsten carbide powder after dry ball milling is ≤135 μm.

[0063] Drying: The moisture content of the crude tungsten carbide powder was removed using a vacuum drying device at a temperature of 115℃ for 4.5 hours. The moisture content of the dried crude tungsten carbide powder was 0.12 wt%.

[0064] High-temperature reduction: A rotary reduction furnace is used to reduce the crude tungsten carbide powder. Hydrogen gas is used to reduce some of the oxidized tungsten powder, with an inlet flow rate of 0.15 m³ / h. 3 / h, pressure of 15KPa, reduction temperature of 1250℃, reduction time of 1h;

[0065] Air jet milling: The crude tungsten carbide powder after high-temperature reduction is subjected to air jet milling. Air jet milling includes two processes: ball milling and sorting. Nitrogen and compressed air are introduced into the ball milling equipment. The ratio of nitrogen to compressed air is 9:1, the pressure is 1.0 MPa, and the air jet milling time is 2.5 hours. After the air jet milling step is completed, tungsten carbide powder is obtained.

[0066] Comparative Example 1 provides a tungsten carbide powder with an average particle size of 1.5 μm, a free carbon content of 0.05%, an oxygen content of 0.24%, and a total content of Co, Ni, Fe, and Ti of 0.8%.

[0067] Comparative Example 2

[0068] Comparative Example 2 provides a ball milling method for electrolytically treated tungsten-containing cemented carbide, which differs from Example 3 in that it does not involve a high-temperature reduction step, as detailed below:

[0069] Comparative Example 2 provides a ball milling method for electrolytically treated tungsten-containing cemented carbide, comprising the following steps:

[0070] Wet ball milling: The recycled tungsten-containing cemented carbide blocks, which have been cleaned after electrolysis, are used as raw materials and ball milled using a conventional ball mill. The ball milling equipment is a closed system with a ball-to-material ratio of 1.3:1, a ball milling speed of 28 r / min, a ball milling time of 2 h, a solid content of 90 wt%, and a particle size of ≤135 μm for the coarse tungsten carbide powder after wet ball milling.

[0071] Drying: The moisture content of the crude tungsten carbide powder was removed using a vacuum drying device at a temperature of 115℃ for 4.5 hours. The moisture content of the dried crude tungsten carbide powder was 0.12 wt%.

[0072] Air jet milling: The coarse tungsten carbide powder is processed by air jet milling, which includes two processes: ball milling and sorting. The ball milling equipment is purged with nitrogen and compressed air at a ratio of 9:1 and a pressure of 1.0 MPa. The air jet milling time is 2.5 hours. After the air jet milling step is completed, tungsten carbide powder is obtained.

[0073] Comparative Example 2 provides a tungsten carbide powder with an average particle size of 1.2 μm, a free carbon content of 0.06%, an oxygen content of 0.40%, and a total content of Co, Ni, Fe, and Ti of 1.2%.

[0074] Comparative Example 3

[0075] Comparative Example 3 provides a ball milling method for electrolytically treated tungsten-containing cemented carbide, which differs from Example 3 in that it omits the air jet milling step, as detailed below:

[0076] Comparative Example 3 provides a ball milling method for electrolytically treated tungsten-containing cemented carbide, comprising the following steps:

[0077] Wet ball milling: The recycled tungsten-containing cemented carbide blocks, which have been cleaned after electrolysis, are used as raw materials and ball milled using a conventional ball mill. The ball milling equipment is a closed system with a ball-to-material ratio of 1.3:1, a ball milling speed of 28 r / min, a ball milling time of 2 h, a solid content of 90 wt%, and a particle size of ≤135 μm for the coarse tungsten carbide powder after wet ball milling.

[0078] Drying: The moisture content of the crude tungsten carbide powder was removed using a vacuum drying device at a temperature of 115℃ for 4.5 hours. The moisture content of the dried crude tungsten carbide powder was 0.12 wt%.

[0079] High-temperature reduction: A rotary reduction furnace is used to reduce the crude tungsten carbide powder. Hydrogen gas is used to reduce some of the oxidized tungsten powder, with an inlet flow rate of 0.15 m³ / h. 3 The reduction process was carried out at a pressure of 15 kPa, a reduction temperature of 1250 °C, and a reduction time of 1 h to obtain tungsten carbide powder.

[0080] Comparative Example 3, due to the lack of air jet milling, produced tungsten carbide powder particles that were too large to meet national standards and therefore unsellable.

[0081] Comparative Example 4

[0082] Comparative Example 4 provides a ball milling method for electrolytically treated tungsten-containing cemented carbide, which differs from Example 3 in that the particle size after wet ball milling is ≤200μm.

[0083] Comparative Example 4 provides a tungsten carbide powder with an average particle size of 4.5 μm, a free carbon content of 0.10%, an oxygen content of 0.24%, and a total content of Co, Ni, Fe, and Ti of 1.0%.

[0084] Comparative Example 5

[0085] Comparative Example 5 provides a ball milling method for electrolytically treated tungsten-containing cemented carbide, which differs from Example 3 in that the moisture content of the dried coarse tungsten carbide powder is 0.5 wt%.

[0086] Comparative Example 5 provides a tungsten carbide powder with an average particle size of 1.5 μm, a free carbon content of 0.08%, an oxygen content of 0.23%, and a total content of Co, Ni, Fe, and Ti of 0.8%.

[0087] Comparative Example 6

[0088] Comparative Example 6 provides a ball milling method for electrolytically treated tungsten-containing cemented carbide, which differs from Example 3 in that the reduction temperature is 900°C.

[0089] Comparative Example 6 provides a tungsten carbide powder with an average particle size of 1.8 μm, a free carbon content of 0.05%, an oxygen content of 0.25%, and a total content of Co, Ni, Fe, and Ti of 0.9%.

[0090] Comparative Example 7

[0091] Comparative Example 7 provides a ball milling method for electrolytically treated tungsten-containing cemented carbide, which differs from Example 3 in that the pressure of the air jet mill is 0.6 MPa.

[0092] Comparative Example 7 provides a tungsten carbide powder with an average particle size of 3.5 μm, a free carbon content of 0.08%, an oxygen content of 0.21%, and a total content of Co, Ni, Fe, and Ti of 0.8%.

[0093] Comparative Example 8

[0094] Comparative Example 8 provides a ball milling method for electrolytically treated tungsten-containing cemented carbide, which differs from Example 3 in that the nitrogen-to-compressed air ratio in the air jet milling step is 7:1.

[0095] Comparative Example 8 provides a tungsten carbide powder with an average particle size of 1.5 μm, a free carbon content of 0.09%, an oxygen content of 0.23%, and a total content of Co, Ni, Fe, and Ti of 0.8%.

[0096] For those skilled in the art, other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations, but obvious variations or modifications derived therefrom are still within the scope of protection of the claims of this invention.

Claims

1. A method for ball milling tungsten-containing cemented carbide after electrolytic treatment, characterized in that, Includes the following steps: The tungsten-containing cemented carbide block, which has undergone electrolysis, is washed in pure water. Then, the washed tungsten-containing cemented carbide block is subjected to wet ball milling. The solid content of the wet ball milling is 85wt%~90wt%, the ball milling speed is 25r / min~30r / min, and the block is dried at a temperature of 110℃~120℃ for 4h~5h. The moisture content of the dried crude tungsten carbide powder is 0.1wt%~0.2wt%, thus obtaining crude tungsten carbide powder. The crude tungsten carbide powder was reduced at high temperature in a hydrogen atmosphere with an inlet flow rate of 0.1 m³ / s. 3 / h~0.2m 3 / h, pressure of 5KPa~30KPa, reduction time of 0.5 h~1 h, reduction temperature of 1000 ℃~1350 ℃; The crude tungsten carbide powder after high-temperature reduction is subjected to air jet milling. In the air jet milling step, nitrogen and compressed air are introduced, and the volume ratio of nitrogen to compressed air is controlled at 8:1 to 10:

1. The air jet milling pressure is 0.8 MPa to 1.2 MPa, and the air jet milling time is 2 h to 3 h to obtain tungsten carbide powder.

2. The ball milling method for an electrolytically treated tungsten-containing cemented carbide according to claim 1, characterized in that, The wet ball milling step has a ball-to-material ratio of 1:1 to 1.5:1 and a milling time of 1.5 h to 2 h.

3. The ball milling method for electrolytically treated tungsten-containing cemented carbide according to claim 1, characterized in that, The particle size of the coarse tungsten carbide powder after ball milling can pass through a 100-mesh sieve.

4. The ball milling method for an electrolytically treated tungsten-containing cemented carbide according to claim 1, characterized in that, In the air jet milling step, the particle size of the tungsten carbide powder after air jet milling is 1.2 μm to 4.0 μm.

5. A tungsten carbide, characterized in that, It is prepared by ball milling of the electrolytically treated tungsten-containing cemented carbide as described in any one of claims 1-4.

6. The tungsten carbide according to claim 5, characterized in that, The tungsten carbide has ≤0.07wt% free carbon, ≤0.2wt% oxygen, and <0.5wt% total content of Co, Ni, Fe, and Ti.