Detection method for uniformity of wax adhesion in granulated cobalt powder, and use thereof

Abstract

A detection method for the uniformity of wax adhesion in granulated cobalt powder, and a use thereof. In the manufacturing process of granulated cobalt powder, the actual content of wax in the obtained granulated cobalt powder is measured in real time, and the uniformity of wax adhesion in the granulated cobalt powder is determined on the basis of wax content fluctuations in the granulated cobalt powder during production. The actual content of the wax in the granulated cobalt powder is measured in real time, so as to determine whether wax distribution is uniform. The uniformity of wax adhesion in the granulated cobalt powder is detected and tracked during the production process, so that granulation process parameters can be adjusted promptly, ensuring the quality of the granulated cobalt powder. During wax content measurement, the wax content in the granulated cobalt powder can be calculated simply by acquiring the density of the used paraffin, the density of the used superfine cobalt powder, and the true density of the granulated cobalt powder product. The detection method of the present invention has simple processes, short testing time, high efficiency, high repeatability, and high practicability, and can be widely applied to the detection of binder dispersion uniformity in metal powder granulation, ensuring the quality of the granulated metal powder.

Description

A method for detecting uniformity of wax in granulated cobalt powder and its application Technical Field

[0001] The invention belongs to the technical field of granulation, relates to the detection of dispersion uniformity of granulated metal powder, and is a method for detecting the uniformity of wax attachment in granulated cobalt powder. Background Art

[0002] Granulated cobalt powder is a product form of cobalt powder. Cobalt powder is the raw material for granulated cobalt powder. By adding paraffin wax, another raw material, to the product, granulated cobalt powder, granulated cobalt powder is obtained. Granulated cobalt powder is primarily used in the cemented carbide industry. It offers advantages such as excellent oxidation resistance, long storage life, high bulk density, easy transportation, good fluidity, and low dust generation. It plays a significant role in improving the cemented carbide production environment and enhancing occupational health.

[0003] During the preparation of granulated cobalt powder, paraffin wax acts as a binder, binding the ultrafine cobalt powder together to form granules. During the cooling and solidification process, the paraffin wax's crystalline structure supports and secures the metal powder, resulting in granules with a defined strength and shape.

[0004] The production steps of granulated cobalt powder in the prior art are:

[0005] 1. Adding materials: Open the valve on the top of the mixer and add the raw material ultrafine cobalt powder as required;

[0006] 2. Wax spraying and mixing: Spray the pre-melted paraffin wax into the mixer tank through the nozzle, then start the mixer to evenly mix the paraffin wax and ultrafine cobalt powder; before spraying the wax, first heat the tank to 55-60℃ with water vapor; then evacuate the inside of the tank and fill it with nitrogen, and repeat this operation twice;

[0007] 3. Powder transfer: After the wax spraying and mixing is completed, the powder is discharged into the silo, and then the material is transferred to the roller conveyor through the elevator;

[0008] 4. Tabletting: The roller machine squeezes the powder, i.e. the mixture of ultrafine cobalt powder and paraffin wax, into thin flakes;

[0009] 5. Granulation: The material enters the crusher, which breaks the flaky material into fine particles;

[0010] 6. Screening: Use ultrasonic vibration screen to screen out granulated cobalt powder that meets the particle size requirements.

[0011] During the actual production process, due to problems such as insufficient mixing in the mixer and clogging of the wax spray port, it is impossible to ensure the uniform distribution of paraffin wax in the granulated cobalt powder. Whether the paraffin wax can be evenly and quantitatively distributed in the granulated cobalt powder has a significant impact on whether the granulated cobalt powder produced meets the requirements. However, the granulated cobalt powder is small in size and a mixture, making it difficult to directly observe the wax adhesion through visual inspection or microscopic instruments. Therefore, there is no detection method for detecting the uniformity of wax adhesion in the granulated cobalt powder in the prior art. Instead, it is assumed that ultrafine cobalt powder and paraffin wax can be evenly mixed in the mixer, combined with the control of the wax spray amount, to obtain the required degree of wax adhesion and ensure the uniformity of wax adhesion in the granulated cobalt powder.

[0012] Metal powder granulation is a key step in most powder metallurgy processes. Except for granulated cobalt powder, all types of granulated powders used in metal powder metallurgy suffer from the same problem: there is no quantitative and qualitative detection method for the dispersion uniformity of the forming agent. It is assumed that the powder and the forming agent have been evenly mixed during the process. However, the actual process will affect the dispersion of the forming agent, which causes fluctuations in the actual product quality. A method that can detect product quality is needed to ensure the quality of granulated metal powder.

[0013] Summary of the Invention

[0014] The problem to be solved by the present invention is that the prior art does not yet have a solution for detecting the uniformity of wax attachment during the cobalt powder granulation process. The production of granulated cobalt powder is affected by the performance of the mixing granulator, and the uniformity quality of the granulated cobalt powder cannot be guaranteed. A method is needed to detect the uniformity of wax attachment of granulated cobalt powder in a timely manner during the production process to ensure the quality of the manufactured product.

[0015] The technical solution of the present invention is: a method for detecting the uniformity of wax attachment in granulated cobalt powder. During the manufacturing process of the granulated cobalt powder, the wax content of the obtained granulated cobalt powder is detected in real time. Based on the fluctuation of the wax content in the granulated cobalt powder during production, the wax attachment uniformity of the granulated cobalt powder is judged. If the fluctuation is greater than a set value, it is considered that the wax attachment is uneven, and the manufacturing process is adjusted.

[0016] Furthermore, during the manufacturing process, a sample of the granulated cobalt powder is taken every 0.5 hours, and the wax content test value of every 5 samples is judged. The maximum test value is subtracted from the minimum test value. If it is less than 0.2%, it is considered that the wax is uniformly attached. Otherwise, it is considered that the wax is unevenly attached. The mixer speed or wax spraying equipment is adjusted, the manufacturing process is repeated, and the test is repeated until the wax uniformity test is passed.

[0017] Furthermore, adjusting the wax spraying equipment includes adjusting the wax spraying speed and checking whether the wax spraying head is clogged.

[0018] Furthermore, the detection of the actual content of wax in the granulated cobalt powder comprises the following steps:

[0019] 1) Obtaining the density ρ1 of the paraffin wax raw material used for granulating cobalt powder;

[0020] 2) obtaining the density ρ2 of the ultrafine cobalt powder raw material used for granulating the cobalt powder;

[0021] 3) obtaining the true density ρ3 of the granulated cobalt powder product;

[0022] 4) Substitute the density ρ1 obtained in step 1), the density ρ2 obtained in step 2), and the true density ρ3 obtained in step 3) into the wax content formula of the granulated cobalt powder: The wax content w in the granulated cobalt powder is obtained 测 .

[0023] Furthermore, the true density ρ3 of the granulated cobalt powder was measured using a true density meter.

[0024] Furthermore, the density ρ1 of the paraffin wax raw material and the density ρ2 of the ultrafine cobalt powder raw material were measured using a true density meter.

[0025] The present invention also proposes a method for detecting the uniformity of dispersion of a molding agent in granulated metal powder, and the method for detecting the uniformity of wax attached to granulated cobalt powder is applied to detect the uniformity of dispersion of the molding agent in the granulated metal powder, wherein the cobalt powder corresponds to the metal powder, the wax corresponds to the molding agent, and the granulated cobalt powder corresponds to the granulated metal powder.

[0026] The present invention provides a method for detecting the uniformity of wax attachment in granulated cobalt powder. The method can quickly and in real time detect the actual content of wax in the granulated cobalt powder, and further determine whether the wax distribution is uniform. The method detects and tracks the uniformity of wax attachment in the granulated cobalt powder during the production process, which is conducive to timely adjusting the process parameters of the granulated cobalt powder and ensuring the quality of the granulated cobalt powder.

[0027] In the detection of wax content, the present invention does not require decomposition and reduction experiments on the granulated cobalt powder to separate the wax and then calculate the wax content. The detection method of the present invention only needs to know the density ρ1 of the paraffin wax used, the density ρ2 of the ultrafine cobalt powder used, and the true density ρ3 of the granulated cobalt powder product to calculate the wax content in the granulated cobalt powder. The detection method has a simple process, short testing time, high efficiency, high repeatability, and high practicality.

[0028] Furthermore, the method for detecting the uniformity of wax attachment in granulated cobalt powder proposed in the present invention can be extended and applied to the detection of the dispersion uniformity of the forming agent in the granulation of metal powder, and can timely adjust and optimize the process of metal powder granulation to ensure the quality of the granulated metal powder. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] FIG1 is a schematic diagram showing the change in wax content in a test sample according to an embodiment of the present invention. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solutions and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below using a preferred embodiment.

[0031] The present invention detects the actual content of wax in the obtained granulated cobalt powder in real time during the manufacturing process of the granulated cobalt powder, and judges the wax attachment uniformity of the granulated cobalt powder based on the fluctuation of the wax content in the granulated cobalt powder in the production batch. If the fluctuation is greater than a set value, it is considered that the wax attachment is uneven, and the manufacturing process is adjusted.

[0032] In the present invention, the detection of the actual wax content in the granulated cobalt powder affects the determination of the uniformity of wax attachment. In order to ensure timely adjustment of the granulation process, it is necessary to quickly and accurately obtain the actual wax content of the granulated cobalt powder. However, the existing technology is unable to achieve this. Most existing technologies use theoretical calculations to ensure accurate feeding amounts, trouble-free equipment, and stable operation to ensure the correctness of the product preparation process, achieve control of the wax dosage, and achieve theoretically uniform wax attachment. However, various material losses and errors in the mixing process are inevitable during the manufacturing process. The resulting granulated cobalt powder product still needs actual testing to improve the process effect of the manufacturing process and ensure product quality.

[0033] The present invention has studied this. Since the actual volume of all materials will not change during the cobalt powder granulation process, that is, the volume of granulated cobalt powder = the volume of paraffin wax + the volume of cobalt powder, assuming that there are m grams of paraffin wax in every 100 grams of granulated cobalt powder, the percentage of wax content is expressed as w 测 If we express it as: V3=V1+V2

[0034] Right now

[0035] Right now

[0036] The wax content is calculated as:

[0037] Where ρ1 is the density of paraffin wax; ρ2 is the density of ultrafine cobalt powder; ρ3 is the true density of granulated cobalt powder; V1 is the volume of paraffin wax; V2 is the volume of cobalt powder; and V3 is the volume of granulated cobalt powder.

[0038] Based on the above research, the present invention found that the wax content of the granulated cobalt powder can be calculated without separating the cobalt powder and paraffin wax, and the detection steps for detecting the wax content in the granulated cobalt powder are obtained:

[0039] 1) Obtaining the density ρ1 of the paraffin wax raw material used for granulating cobalt powder;

[0040] 2) obtaining the density ρ2 of the ultrafine cobalt powder raw material used for granulating the cobalt powder;

[0041] 3) obtaining the true density ρ3 of the granulated cobalt powder product;

[0042] 4) Substitute the density ρ1 obtained in step 1), the density ρ2 obtained in step 2), and the true density ρ3 obtained in step 3) into the wax content formula of the granulated cobalt powder: The wax content w in the granulated cobalt powder is obtained 测 .

[0043] Based on the detection of wax content in the above embodiment, the present invention has two optional preferred methods. One is to use a true density meter to detect the three densities, namely the density ρ1 of the paraffin raw material, the density ρ2 of the ultrafine cobalt powder raw material, and the true density ρ3 of the granulated cobalt powder. This method has the best accuracy because the true density of each product has certain fluctuations. All densities are measured using a true density meter, and the results are the most accurate. Another method is to take into account the detection time of the true density meter, and the fact that ultrafine cobalt powder and paraffin are raw materials, and their densities are known by default during manufacturing. For example, a fixed empirical value density or theoretical density is usually used as a process parameter in the process. The practice of the present invention shows that if a fixed empirical value is used for paraffin and ultrafine cobalt powder for detection, the effect on the detection result of wax uniformity is small and within an acceptable range. In the above-mentioned wax content detection, it is preferred to use only a true density meter to measure the true density ρ3 of the granulated cobalt powder product, which can improve the detection speed and achieve a balance between the accuracy of the detection result and the detection speed.

[0044] The following describes the implementation of the present invention through an embodiment.

[0045] First, the actual wax content in the obtained granulated cobalt powder was determined:

[0046] 1) When preparing granulated cobalt powder with a wax content standard value w of 2.20%, 20 g of the granulated cobalt powder is taken as a test sample. In this embodiment, the densities of the ultrafine cobalt powder and paraffin wax are known by default, and the density of paraffin wax is ρ1 = 0.91 g / cm 3 The density of ultrafine cobalt powder is ρ2=8.9g / cm 3 .

[0047] 2) Using a true density meter to measure the true density of the granulated cobalt powder product, ρ3 = 7.4889 g / cm 3 In this embodiment, the true density detection data is measured using an AccuPycII series fully automatic gas displacement method true density meter.

[0048] 3) Substitute the wax content formula of granulated cobalt powder into Get w 测 =2.15%.

[0049] In this embodiment, 测 The difference from the required standard value of 2.20% is only 0.05%, which is within the acceptable range (±0.1%), indicating that the current sample is a qualified sample.

[0050] The wax content of multiple batches of granulated cobalt powder was measured using the wax content detection method described above. Ten batches of granulated cobalt powder were tested multiple times, with each batch weighing 500 kg. Samples were taken every 0.5 hours during the product preparation process, with five samples taken from each batch, each weighing 20 g. The test data are shown in Table 1:

[0051] Table 1 Wax content test data of granulated cobalt powder samples

[0052] In this embodiment, the uniformity of the wax attachment is determined by the numerical value of the wax content of the batch product. A wax content curve is established with the batch as the horizontal axis and the detected wax content as the vertical axis. The closer the curve is to a straight line and the smaller the fluctuation is, the better the uniformity. The fluctuation here is preferably determined by subtracting the minimum detection value from the maximum detection value, with 0.2% as the fluctuation threshold. According to Table 1, a curve graph is obtained, as shown in Figure 1. From the curve graph of the first 5 batches of samples, i.e., the curve of the abscissa 1 to 25 part, it can be seen from the analysis that the wax content of the first 5 batches of samples is 2.198-2.206% from the average value, indicating that the amount of paraffin added is accurate, and the standard is 2.20 ± 0.1%. However, the error exceeds 0.2% by subtracting the minimum detection value from the maximum detection value within the batch, and the fluctuation is large, indicating that the wax attachment is uneven. At this time, the manufacturing process is adjusted. The present embodiment uses a double-cone mixing device, which is a cylinder rotating with a wax spray nozzle. By adjusting the speed and the wax spraying, such as adjusting the wax spraying speed or checking whether the wax spraying nozzle is blocked, the production is re-manufactured. It can be seen from the curve graph of the latter 5 batches of samples that after adjustment, the wax content fluctuation becomes smaller, the wax attachment uniformity becomes better, and the wax content is 2.198-2.204% from the average value, indicating that the amount of paraffin added is also accurate. Judging from the respective data of the above 10 batches of 50 samples, for the quality of wax-attached granulated cobalt powder, the detection method of the present invention, on the one hand, detects the actual content of wax in the granulated cobalt powder in real time, which can be used to determine whether the wax content meets the basic quality requirement of 2.20%. At the same time, the wax-attached uniformity of the granulated cobalt powder is detected by the change in wax content, further ensuring the quality of the granulated cobalt powder, making the quality of multiple batches of granulated cobalt powder stable, and the entire detection process does not require operations such as separation of cobalt powder and paraffin wax on the granulated cobalt powder. The detection process is fast and can be carried out in real time with the manufacturing process, and real-time feedback is provided to adjust the manufacturing process, thereby improving the process effect of the granulated cobalt powder.

[0053] The method for detecting the uniformity of wax attachment in granulated cobalt powder described in the above embodiment of the present invention can also be further applied to the detection of the uniformity of dispersion of the molding agent in granulated metal powder, wherein the cobalt powder corresponds to the metal powder, the wax corresponds to the molding agent, and the granulated cobalt powder corresponds to the granulated metal powder. By detecting the content of the molding agent in the granulated metal powder preparation process, the uniformity of dispersion of the molding agent can be quickly detected, which is beneficial to improving the quality of the granulated metal powder and maintaining the stability of the quality.

Claims

1. A method for detecting the uniformity of wax adhesion in granulated cobalt powder, characterized in that During the manufacturing process of granulated cobalt powder, the wax content of the obtained granulated cobalt powder is detected in real time. Based on the fluctuation of the wax content in the granulated cobalt powder during production, the wax coating uniformity of the granulated cobalt powder is judged. If the fluctuation is greater than the set value, it is considered that the wax coating is uneven, and the manufacturing process is adjusted.

2. The detection method for the uniformity of wax adhesion in granulated cobalt powder according to claim 1 is characterized in that During the manufacturing process, samples of the granulated cobalt powder are taken every 0.5 hours, and the wax content detection values of every 5 samples are judged. The maximum detection value is subtracted from the minimum detection value. If it is less than 0.2%, it is considered that the wax coating is uniform, otherwise it is considered that there is uneven wax coating. The rotation speed of the mixer or the wax spraying equipment is adjusted, and the manufacturing process is carried out again and detected again until the wax coating uniformity test is passed.

3. The detection method for the uniformity of wax adhesion in granulated cobalt powder according to claim 2, characterized in that Adjusting the wax spraying equipment includes adjusting the wax spraying speed and checking whether the wax spraying head is blocked.

4. The detection method for the uniformity of wax adhesion in granulated cobalt powder according to claim 1, characterized in that The detected wax content in the granulated cobalt powder is the true content of the detected wax, including the following steps: 1) Obtain the density ρ1 of the paraffin raw material used for the granulated cobalt powder; 2) Obtain the density ρ2 of the ultrafine cobalt powder raw material used for the granulated cobalt powder; 3) Obtain the true density ρ3 of the granulated cobalt powder product; 4) Substitute the density ρ1 obtained in step 1), the density ρ2 obtained in step 2), and the true density ρ3 obtained in step 3) into the formula for the wax content in the granulated cobalt powder Obtain the wax content w in the granulated cobalt powder 测 .

5. The detection method for the uniformity of wax adhesion in granulated cobalt powder according to claim 4, wherein The true density ρ3 of the granulated cobalt powder is measured using a true density meter.

6. The detection method for the uniformity of wax adhesion in granulated cobalt powder according to claim 5, characterized in that The density ρ1 of the paraffin raw material and the density ρ2 of the ultrafine cobalt powder raw material are measured using a true density meter.

7. A method for detecting the uniformity of dispersibility of a forming agent in granulated metal powder, characterized in that The detection method for the uniformity of the dispersibility of the forming agent in the granulated metal powder is carried out by applying the detection method for the wax coating uniformity in the granulated cobalt powder described in any one of claims 1 to 6, wherein the cobalt powder corresponds to the metal powder, the wax corresponds to the forming agent, and the granulated cobalt powder corresponds to the granulated metal powder.

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