High-activity rare earth alloy low-temperature anti-oxidation sample preparation method and grinding tank gas replacement online monitoring device

Abstract

The present application relates to metallurgical analysis sample preparation, in particular to a high-activity rare earth alloy low-temperature anti-oxidation sample preparation method and a grinding pot gas replacement online monitoring device. The high-activity rare earth alloy low-temperature anti-oxidation sample preparation method comprises the following steps: liquid nitrogen precooling of a high-activity rare earth alloy block sample; low-temperature staged crushing of the pre-cooled sample; loading of the crushed sample into a grinding pot; connecting the grinding pot to the grinding pot gas replacement online monitoring device; performing a cycle process of vacuumizing, vacuum pressure maintaining, argon filling, argon pressure maintaining and oxygen content detection; low-temperature step grinding; opening the grinding pot in an argon protection environment; and sieving and collecting the sample. The present application combines low-temperature staged crushing, low-temperature step grinding and grinding pot gas replacement, and reduces the whole process of high-activity rare earth alloy sample preparation.

Description

Technical Field

[0001] This invention relates to the preparation of metallurgical analysis samples, and more particularly to a method for preparing high-activity rare earth alloy samples at low temperature with anti-oxidation properties and an online monitoring device for gas replacement in grinding jars. Background Technology

[0002] Rare earth alloys such as cerium-iron alloys are important additives in the smelting of special steels, and the results of their oxygen content and other component tests directly affect production control and quality assessment. These samples are highly reactive and readily react with oxygen in the air during crushing, grinding, and transfer, leading to oxidation of the test samples and consequently, higher oxygen content test results.

[0003] Existing sample preparation methods typically have the following problems:

[0004] First, during room temperature crushing and grinding, the fresh cross-section of the sample is continuously exposed to air, making oxidation inevitable. Second, conventional manual double-row gas replacement relies mainly on the operator's experience and judgment, lacking online oxygen content detection and pressure threshold indication. Third, there is a risk of backflow of air when the pump is stopped or due to misoperation. Fourth, commercial glove boxes or fully automated gas replacement equipment are expensive and require significant modifications to existing laboratory equipment. Fifth, the consistency of parameters is poor when different operators perform the same sample preparation process, making it difficult to form a reproducible standardized sample preparation method.

[0005] Therefore, it is necessary to propose a sample preparation method and device that takes into account low-temperature oxidation prevention, online monitoring of gas replacement, pressure safety interlock, and low-cost modification. Summary of the Invention

[0006] This invention addresses the shortcomings of existing technologies by providing a method for preparing high-activity rare earth alloy samples at low temperatures to prevent oxidation, and an online monitoring device for gas replacement in grinding tanks.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: a low-temperature anti-oxidation sample preparation method for highly active rare earth alloys, comprising the following steps:

[0008] (1) Pre-cool the high-activity rare earth alloy block sample with liquid nitrogen;

[0009] (2) The pre-cooled sample is subjected to low-temperature grading and crushing. During the crushing process, liquid nitrogen is continuously sprayed onto the crushing roller surface to keep the crushing zone at a low temperature and crush the sample to the predetermined particle size.

[0010] (3) Load the crushed sample into the grinding jar, connect the grinding jar to the online gas replacement monitoring device of the grinding jar, and perform a cycle of vacuuming, vacuum pressure holding, argon filling, argon filling pressure holding and oxygen content detection until the oxygen content reaches the set threshold.

[0011] (4) Place the grinding jar that has undergone gas replacement into a low-temperature ball mill for low-temperature step grinding;

[0012] (5) Open the grinding jar under argon protection, sieve and collect the sample.

[0013] Furthermore, the particle size of the high-activity rare earth alloy block sample in step (1) is 4-8 cm. It is sprayed with liquid nitrogen evenly and pre-cooled for 3 minutes until frost forms on the sample surface.

[0014] Furthermore, the low-temperature grading crushing in step (2) includes three stages: coarse crushing, fine crushing, and roller shaping. During the low-temperature grading crushing process, liquid nitrogen is continuously sprayed, with the liquid nitrogen outlet pressure controlled at 0.08 to 0.10 MPa, the liquid nitrogen spray flow rate controlled at 1.2 to 1.5 L / min, and the roller surface temperature maintained at -80 to -120℃.

[0015] Further, in step (3), when the vacuum pressure reaches -0.095MPa, the vacuum pump and vacuum solenoid valve are turned off, and the manual valve set on the vacuum drain is prompted to be closed manually. After manual confirmation, the vacuum pressure holding process begins. After the vacuum pressure holding process is completed, the manual valve set on the inert gas drain is prompted to be opened manually. After manual confirmation, the inert gas solenoid valve is opened to fill argon gas, and the oxygen content is detected synchronously by the oxygen content detection unit set on the bypass sampling branch.

[0016] If the oxygen content is ≤0.8%, close the inert gas solenoid valve and start argon charging and pressure holding;

[0017] If the oxygen content does not meet the standard and the argon filling pressure reaches the preset filling pressure threshold, the inert gas solenoid valve will be closed and the next replacement cycle will begin.

[0018] Furthermore, in step (4), the low-temperature stepped grinding includes a rapid pre-cooling stage, a stepped speed-up stage, and a stable grinding stage. In the rapid pre-cooling stage, the grinding speed is 300 rpm and the grinding temperature is cooled to -45℃. In the stepped speed-up stage, the grinding speed is gradually increased from 300 rpm to 400 rpm and the grinding temperature is maintained at -45℃±1℃. In the stable grinding stage, the grinding speed is 400 rpm and the grinding temperature is maintained at -45℃.

[0019] An online monitoring device for gas replacement in a grinding jar for low-temperature anti-oxidation sample preparation of highly active rare earth alloys includes a dual-row tube body, a vacuum passage, an inert gas filling passage, and an end bypass sampling and monitoring component.

[0020] The dual-row pipe body includes a vacuum row and an inert gas row. The inert gas row has multiple grinding tank interfaces for connecting to the grinding tank and an exhaust port located at the end of the inert gas row.

[0021] The vacuum pumping passage is connected to the vacuum drain, and the inert gas filling passage is connected to the inert gas drain;

[0022] The end bypass sampling monitoring component includes a diversion connector disposed at the exhaust port, a bypass sampling branch connected to the diversion connector, and an oxygen content detection unit disposed on the bypass sampling branch.

[0023] The diversion connector is used to allow a portion of the exhaust gas from the exhaust port to be discharged along the main exhaust direction, while the other portion enters the bypass sampling branch, so that the oxygen content detection unit can perform online oxygen content detection on the replacement gas that flows from the multiple grinding tank interfaces to the exhaust port.

[0024] Furthermore, the bypass sampling branch is provided with a one-way valve, a buffer flow stabilizer, a flow control display component, an oxygen content detection unit, and an exhaust gas barrier component in sequence along the airflow direction.

[0025] Furthermore, the buffer flow stabilizer is a buffer bottle, the flow control display component includes a rotor flow meter and / or a flow regulating valve, the rotor flow meter is used to display the gas flow rate of the bypass sampling branch, the flow regulating valve is used to regulate the gas flow rate of the bypass sampling branch, the tail gas barrier is a water seal bottle, and the oxygen content detection unit includes an oxygen content sensor flow cell and an oxygen sensor disposed in the oxygen content sensor flow cell.

[0026] Furthermore, the one-way valve, the buffer flow stabilizer, and the exhaust gas barrier together constitute an anti-backflow structure to prevent external gas or liquid from entering the inert gas outlet in the reverse direction through the bypass sampling branch.

[0027] Furthermore, it also includes an intelligent monitoring and alarm module, which is electrically connected to the oxygen content detection unit and configured to output a prompt signal or alarm signal based on the oxygen content detected by the oxygen content detection unit;

[0028] The intelligent monitoring and alarm module is also electrically connected to the pressure detection unit, which is used to detect the pressure inside the dual-row pipe body. The intelligent monitoring and alarm module is configured to perform a linkage prompt or linkage alarm based on the pressure value detected by the pressure detection unit and the oxygen content detected by the oxygen content detection unit.

[0029] The vacuum stack is equipped with a pressure detection port, and the pressure detection unit is connected to the pressure detection port;

[0030] The vacuum outlet is provided with a vacuum inlet. The vacuum pumping passage includes a vacuum pump, a filter, and a vacuum control valve connected in sequence. The vacuum control valve is connected to the vacuum inlet. The inert gas charging passage includes an inert gas source, a pressure reducing valve, a check valve, and a charging control valve (inert gas solenoid valve) connected in sequence. The charging control valve is connected to the inert gas outlet.

[0031] Compared with the prior art, the present invention has the following advantages.

[0032] This invention combines low-temperature graded crushing, low-temperature stepped grinding, and gas replacement in the grinding tank to reduce oxidation throughout the entire process of preparing highly reactive rare earth alloy samples. It also enables online detection of oxygen content at the end of the replacement process and reduces the risk of backflow caused by pump stoppage, misoperation, or pressure fluctuations through a protective structure consisting of a one-way valve, a GL45 buffer bottle, a flow cell, and a water seal bottle. Attached Figure Description

[0033] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. The scope of protection of the present invention is not limited to the following description.

[0034] Figure 1 This is a flowchart of the low-temperature anti-oxidation sample preparation method for high-activity rare earth alloys in Example 1.

[0035] Figure 2 This is a system diagram of the online monitoring device for gas replacement in a grinding tank for manual double-row pipes, as shown in Example 2.

[0036] Figure 3 for Figure 2 Enlarged view of a part Figure 1 .

[0037] Figure 4 for Figure 2 Enlarged view of a part Figure 2 (Schematic diagram of the end-of-line bypass sampling and monitoring component).

[0038] Figure 5 This is a system diagram of an online monitoring device using argon as an inert gas source, as shown in Example 2.

[0039] Figure 6 This is a graph showing the grinding process parameters at low temperatures.

[0040] In the diagram, 1 represents the body of the double-row pipe;

[0041] 11 is the upper vacuum port; 12 is the lower inert gas port; 13 is port A; 14 is the grinding jar interface;

[0042] 141 is the first grinding jar; 142 is the second grinding jar; 143 is the third grinding jar;

[0043] 15 is a manual valve; 16 is port B; 17 is port C; 18 is an exhaust port;

[0044] 2 is the end-point bypass sampling and monitoring component; 21 is the shunt connector;

[0045] 3 represents the intelligent monitoring and alarm module; 31 represents the microcontroller main control unit; 32 represents the pressure detection unit;

[0046] 41 is a vacuum pump; 42 is an inert gas source; 43 is a flow cell for an oxygen content sensor; 431 is an oxygen sensor;

[0047] 45 is a filter; 46 is a flow control display component; 47 is a vacuum solenoid valve; 48 is a pressure reducing valve; 49 is an inert gas inlet check valve;

[0048] 50 is an inert gas solenoid valve; 51 is a three-way valve; 53 is a bypass check valve; 54 is a GL45 buffer bottle; 55 is a water seal bottle. Detailed Implementation

[0049] The embodiments of this application will be further described in detail below with reference to the accompanying drawings and examples. The detailed description of the following embodiments and the accompanying drawings are used to illustrate the principles of this application by way of example, but should not be used to limit the scope of this application. This application can be implemented in many different forms and is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

[0050] These embodiments are provided to make the application thorough and complete, and to fully express the scope of the application to those skilled in the art. It should be noted that, unless otherwise specifically stated, the relative arrangement of components and steps, material composition, numerical expressions, and values ​​illustrated in these embodiments should be interpreted as merely exemplary and not as limiting.

[0051] It should be noted that, in the description of this application, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," and "outer," etc., indicating orientation or positional relationship, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0052] Furthermore, the terms "first," "second," and similar terms used in this application do not indicate any order, quantity, or importance, but are merely used to distinguish different parts. "Vertical" is not strictly vertical, but within the permissible margin of error. "Parallel" is not strictly parallel, but within the permissible margin of error. Terms such as "including" or "contains" mean that the element preceding the word encompasses the element listed after it, and do not exclude the possibility of encompassing other elements as well.

[0053] It should also be noted that, in the description of this application, unless otherwise expressly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this application depending on the specific circumstances. When a specific device is described as being located between a first device and a second device, an intermediary device may or may not be present between the specific device and the first or second device.

[0054] All terms used in this application have the same meaning as understood by one of ordinary skill in the art to which this application pertains, unless otherwise specifically defined. It should also be understood that terms defined in general dictionaries should be interpreted as having meanings consistent with their meanings in the context of the relevant art, and not as idealized or highly formalized, unless expressly defined herein.

[0055] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, they should be considered part of the specification.

[0056] like Figure 1 As shown in Example 1: Low-temperature anti-oxidation sample preparation method for cerium-iron alloy.

[0057] S1. Take a block sample of cerium-iron alloy with a particle size of 4-8 cm. Pre-cool the sample by uniformly spraying it with liquid nitrogen for about 3 minutes until frost appears on the sample surface.

[0058] S2. Subsequently, low-temperature grading and crushing are carried out, which includes three stages: coarse crushing, fine crushing, and roller shaping. During the crushing process, liquid nitrogen is continuously sprayed onto the roller surface to maintain the roller surface temperature within the range of -80 to -120°C. The liquid nitrogen outlet pressure is controlled at 0.08 to 0.10 MPa, and the liquid nitrogen injection flow rate is controlled at 1.2 to 1.5 L / min. After crushing, the sample passes through a 3 mm standard sieve.

[0059] S3. Load samples ≤3mm into the grinding jar, add grinding balls according to process requirements, and seal. Connect the grinding jar to a dual-row tubular gas replacement online monitoring device, and perform the following procedures for the grinding jar: vacuuming, manual confirmation of pressure holding, argon filling, simultaneous oxygen measurement, and determining whether to continue the cycle based on oxygen content. During vacuuming, the vacuum pump and vacuum solenoid valve will automatically start; when the pressure reaches -0.095MPa, the vacuum pump and vacuum solenoid valve will automatically shut off, and a voice module will prompt, "Please manually close the high vacuum valve of the vacuum line, please confirm." After manual voice confirmation, the pressure holding process will begin. After the pressure holding period is completed, the voice module prompts "Please manually open the argon exhaust valve". After manual voice confirmation, the argon solenoid valve is opened to fill with argon. While filling with argon, the oxygen sensor on the D-port bypass continuously monitors the oxygen content of the replacement gas flowing from multiple grinding tanks to the exhaust port. If the oxygen content is ≤0.8%, the argon solenoid valve is closed and the argon filling and pressure holding process begins. The results are recorded after the pressure holding period. If the oxygen content does not meet the standard and the pressure reaches the upper limit of 0.2MPa, the argon solenoid valve is closed and the next round of vacuuming and argon filling cycle begins.

[0060] S4. Place the replaced grinding jar into a low-temperature ball mill for low-temperature stepped grinding. The grinding process includes a rapid pre-cooling stage (0–5 min), a stepped speed-up stage (5–15 min), and a stable grinding stage (15–25 min). During the rapid pre-cooling stage, the rotation speed is 300 rpm and the temperature is lowered to -45℃. During the stepped speed-up stage, the rotation speed is gradually increased from 300 rpm to 400 rpm, and the temperature is stabilized at -45℃ ± 1℃. During the stable grinding stage, the rotation speed is 400 rpm, and the temperature is maintained at -45℃. After grinding, open the grinding jar under argon protection, sieve using a 0.5 mm standard sieve, and collect the sample.

[0061] In one implementation, the cryogenic ball mill is a planetary ball mill or a vibratory ball mill equipped with refrigeration function and programmable speed control. This cryogenic ball mill is equipped with a refrigeration system (e.g., liquid nitrogen refrigeration or compressor refrigeration) that can drive the grinding jar to maintain a certain low-temperature environment during the grinding process. The cryogenic ball mill can also be equipped with a frequency converter control system, capable of executing multi-stage grinding programs including rapid precooling, stepped speed increase, and constant-speed grinding.

[0062] Example 2, as follows Figure 2-5 As shown, the online monitoring device for gas replacement in a grinding tank with manual double-row tubes includes a double-row tube body 1, a vacuum passage, an inert gas filling passage, and an end bypass sampling and monitoring component 2; in this embodiment, argon is used as the inert gas. Wherein:

[0063] The dual-row pipe body 1 includes an upper vacuum line 11 and a lower inert gas line 12. Both the upper vacuum line 11 and the lower inert gas line 12 are equipped with manual valves 15. The upper vacuum line 11 has ports A 13 and B 16, while the lower inert gas line 12 has a port C 17, multiple grinding jar interfaces 14 for connecting grinding jars, and an exhaust port 18 at the end of the lower inert gas line 12. The vacuuming passage is connected to the upper vacuum line 11, and the inert gas filling passage is connected to the lower inert gas line 12. Port B 16 of the upper vacuum line 11 is selectively connected to port C 17 of the lower inert gas line 12 via a three-way valve 51, so that each grinding jar can be evacuated through the lower inert gas line 12 during the vacuuming phase.

[0064] The end-of-line bypass sampling monitoring component 2, also known as the D-port micro-damage bypass oxygen content monitoring module, specifically includes a diversion connector 21 located at the exhaust port 18, a bypass sampling branch connected to the diversion connector 21, and an oxygen content detection unit located on the bypass sampling branch. The diversion connector 21 has an inlet end connected to the exhaust port 18, a straight end connected along the main exhaust direction, and a bypass end connected to the bypass sampling branch. The straight end forms the main exhaust passage, and the bypass end forms the bypass sampling passage. The oxygen content detection unit is located on the bypass sampling branch and is connected to the replacement gas that converges from multiple grinding tank interfaces 14 to the exhaust port 18.

[0065] During the gas replacement process, the manual valves 15 at the interfaces of multiple grinding tanks are open, creating a connected cavity between the inner cavity of each grinding tank and the lower inert gas outlet. During the vacuuming phase, residual gas in the grinding tanks is extracted as the system pressure decreases; during the inert gas filling phase, inert gas enters the lower inert gas outlet and replenishes the inner cavity of each grinding tank; during the exhaust phase, residual gas in the grinding tanks mixes with the inert gas and flows through the lower inert gas outlet to the exhaust port. Therefore, the end-point bypass sampling and monitoring component located at the exhaust port can perform online detection of the oxygen content of the gas flowing from the multiple grinding tanks after replacement.

[0066] In a preferred embodiment, the diversion connector 21 is a three-way connector, and the air inlet end of the three-way connector is plugged into, sleeved into, or threadedly connected to the exhaust port 18.

[0067] Preferably, the bypass sampling branch is equipped with a flow control display component 46, which is used to monitor the flow rate and ensure that the gas volume flow rate entering the bypass sampling branch is less than 5% of the total exhaust flow rate at the exhaust port 18. The bypass sampling branch is provided with a bypass check valve 53, a buffer flow stabilizer, a flow control display component 46, an oxygen content detection unit, and an exhaust gas barrier component in sequence along the bypass airflow direction.

[0068] In a preferred embodiment, the buffer flow stabilizer is a GL45 buffer bottle 54, the flow control and display assembly 46 includes a rotor flowmeter and / or a flow regulating valve, the exhaust gas barrier is a water seal bottle 55, and the oxygen content detection unit includes an oxygen content sensor flow cell 43 and an oxygen sensor 431 disposed within the oxygen content sensor flow cell 43. Furthermore, the bypass check valve 53, the buffer flow stabilizer, and the exhaust gas barrier together constitute an anti-backflow structure, which prevents external gas or liquid from entering the lower inert gas outlet 12 via the bypass sampling branch. The water seal bottle is located at the end of the bypass sampling branch to prevent external air or liquid from entering the bypass sampling branch in reverse. The oxygen content sensor flow cell is disposed between the GL45 buffer bottle and the water seal bottle to form a stable detection chamber and accommodate the oxygen sensor.

[0069] In a preferred embodiment, the oxygen content detection unit includes an oxygen sensor 431. The oxygen sensor 431 is used to simultaneously detect the oxygen content of the gas flowing from the grinding tanks connected to the multiple grinding tank interfaces 14 after displacement, that is, to detect the overall oxygen content after the displacement gases from the multiple grinding tank interfaces have flowed together. It should be noted that the oxygen content detection unit detects the overall oxygen content after the gas flows from the multiple grinding tank interfaces, and it is used to determine the overall compliance status of the gas displacement process in the parallel grinding tanks. When it is necessary to independently confirm a single grinding tank, other grinding tank interfaces can be closed, and only the interface of the grinding tank to be tested can be opened, allowing its displacement gas to flow separately to the exhaust port for detection.

[0070] In a preferred embodiment, there are three grinding tank interfaces 14, which are arranged in parallel in the lower inert gas outlet 12 and are used to connect the first grinding tank 141, the second grinding tank 142 and the third grinding tank 143 respectively.

[0071] Preferably, the system further includes an intelligent monitoring and alarm module 3, which is electrically connected to the oxygen content detection unit and configured to output a prompt signal or alarm signal based on the oxygen content detected by the oxygen content detection unit. Specifically, the intelligent monitoring and alarm module 3 includes a microcontroller main control unit 31, which is electrically connected to the oxygen sensor 431 and the pressure detection unit 32, respectively. The pressure detection unit 32 is used to detect the system pressure within the dual-row pipe body 1, and the intelligent monitoring and alarm module 3 is configured to perform a linkage prompt or linkage alarm based on the system pressure and oxygen content. Moreover, the pressure detection unit 32 is connected to port B 16 of the upper vacuum duct 11 and selectively connected to port C 17 of the lower inert gas duct 12 through a three-way valve 51 to achieve switching of the vacuum path and pressure detection of the upper vacuum duct 11 or the lower inert gas duct 12.

[0072] When detecting the pressure of the upper vacuum drain, the three-way valve is used to connect the pressure detection unit to the upper vacuum drain; when detecting the pressure of the lower inert gas drain, the three-way valve is used to connect the pressure detection unit to the lower inert gas drain; when it is not necessary to connect the two pipelines, the three-way valve is in the closed or isolated state to avoid unintended connection between the vacuum drain and the inert gas drain.

[0073] As a preferred embodiment, the pressure detection unit 32 is an intelligent digital display pressure gauge with two independent relay outputs, which are used to set the vacuum threshold and the inert gas filling threshold, respectively.

[0074] As a preferred embodiment, the vacuum threshold is -0.095MPa, the inert gas filling threshold is a preset filling pressure threshold, and the intelligent monitoring and alarm module 3 outputs corresponding operation prompt signals or alarm signals based on the vacuum threshold, the inert gas filling threshold and the preset oxygen content threshold.

[0075] Preferably, the vacuum pumping passage includes a vacuum pump 41, a filter 45, and a vacuum solenoid valve 47 connected in sequence, with the vacuum solenoid valve 47 connected to port A 13 of the upper vacuum outlet 11. The inert gas filling passage includes an inert gas source 42, a pressure reducing valve 48, an inert gas inlet check valve 49, and an inert gas solenoid valve 50 connected in sequence, with the inert gas solenoid valve 50 connected to port C 17 of the lower inert gas outlet 12.

[0076] See Figure 4 In a preferred embodiment, the inert gas source 42 is an argon cylinder, and the lower inert gas outlet 12 is a lower argon outlet. The rotor flowmeter has a range of 6–60 mL / min, the GL45 buffer bottle 54 has a volume of 500 mL, and the bypass check valve 53 has an opening pressure of 0.02 MPa. The oxygen sensor 431 is an electrochemical oxygen sensor with a measurement range of 0–25% VOL, a measurement accuracy of ±0.1% VOL, and a response time ≤15 s.

[0077] Example 3: Low-temperature stepped grinding parameters.

[0078] like Figure 6 As shown, the low-temperature stepped grinding process includes three stages: rapid precooling, stepped speed increase, and stable grinding. The rapid precooling stage lasts 0–5 minutes at a grinding speed of 300 rpm, with the temperature dropping from room temperature to -45°C. The stepped speed increase stage lasts 5–15 minutes, with the grinding speed gradually increasing from 300 rpm to 400 rpm, and the temperature stabilizing at -45°C ± 1°C. The stable grinding stage lasts 15–25 minutes at a grinding speed of 400 rpm, with the temperature maintained at -45°C. These process parameters reduce the oxidation risk caused by grinding temperature increases and improve sample preparation repeatability.

[0079] Example 4: As an optional solution, the device also includes a circuit control module, which uses a 24V DC industrial power supply and a 5V independent adapter for separate power supply, and is grounded according to the field wiring requirements. The ESP32-S3 main control unit collects signals from the JXM-O2 oxygen sensor, BME280 environmental sensor, MDS828Z intelligent digital display pressure gauge, etc., and controls the slave station 8-channel relay board. The R1 vacuum enable relay is connected in series with the AL1 limit contact of the pressure gauge, and the R2 inflation enable relay is connected in series with the AL2 limit contact of the pressure gauge. Specifically, as a possible implementation, the circuit control module includes the ESP32-S3 main control unit, a 24V DC industrial power supply, a 5V independent adapter, a system ground, an 8-channel relay board, a JXM-O2 oxygen sensor, a BME280 environmental sensor, an ST7789 display screen, an MDS828Z intelligent digital display pressure gauge, a voice broadcast module, and an audible and visual alarm. The TXD terminal of the JXM-O2 oxygen sensor is connected to GPIO10 of the ESP32-S3 via a 1kΩ resistor; the SDA terminal of the BME280 is connected to GPIO8, and the SCL terminal is connected to GPIO9; the CS, DC, RST, SDA, SCL, and BL terminals of the ST7789 display are connected to GPIO41, GPIO40, GPIO45, GPIO47, GPIO21, and GPIO42, respectively. The slave station's 8-channel relay board is powered by a 24V DC industrial power supply. R1 vacuum enable relay, R2 inflation enable relay, R3 grinding enable relay, R4 pressure relief control relay, and R5 abnormal alarm relay are used for authorization or alarm output of corresponding actions. The MDS828Z intelligent digital pressure gauge 32 is powered by 24V and connected to the slave station via RS485 A / B, providing two limit contacts, AL1 and AL2. The R1 vacuum enable relay is connected in series with the AL1 limit contact, and the R2 inflation enable relay is connected in series with the AL2 limit contact. The corresponding action can only be executed when both the timing authorization of the ESP32-S3 and the pressure gauge hardware limit are met; if either condition is broken, the corresponding action will stop. This is only one possible implementation method of control and will not be elaborated here.

[0080] The embodiments of this application have now been described in detail. To avoid obscuring the concept of this application, some details known in the art have not been described. Those skilled in the art can fully understand how to implement the technical solutions disclosed herein based on the above description.

[0081] While specific embodiments of this application have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and are not intended to limit the scope of this application. Those skilled in the art should understand that modifications can be made to the above embodiments or equivalent substitutions can be made to some technical features without departing from the scope and spirit of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any manner.

Claims

1. A method for preparing samples of highly active rare earth alloys for low-temperature oxidation prevention, characterized in that, Includes the following steps: (1) Pre-cool the high-activity rare earth alloy block sample with liquid nitrogen; (2) The pre-cooled sample is subjected to low-temperature grading and crushing. During the crushing process, liquid nitrogen is continuously sprayed onto the crushing roller surface to keep the crushing zone at a low temperature and crush the sample to the predetermined particle size. (3) Load the crushed sample into the grinding jar, connect the grinding jar to the online gas replacement monitoring device of the grinding jar, and perform a cycle of vacuuming, vacuum pressure holding, argon filling, argon filling pressure holding and oxygen content detection until the oxygen content reaches the set threshold. (4) Place the grinding jar that has undergone gas replacement into a low-temperature ball mill for low-temperature step grinding; (5) Open the grinding jar under argon protection, sieve and collect the sample.

2. The method for preparing low-temperature anti-oxidation samples of highly active rare earth alloys according to claim 1, characterized in that, The particle size of the high-activity rare earth alloy block sample in step (1) is 4-8 cm. It is sprayed with liquid nitrogen evenly and pre-cooled for 3 minutes until frost forms on the sample surface.

3. The method for preparing low-temperature anti-oxidation samples of highly active rare earth alloys according to claim 1, characterized in that, The low-temperature grading crushing in step (2) includes three stages: coarse crushing, fine crushing and roller shaping. Liquid nitrogen is continuously sprayed during the low-temperature grading crushing process. The liquid nitrogen outlet pressure is controlled at 0.08 to 0.10 MPa, the liquid nitrogen spray flow rate is controlled at 1.2 to 1.5 L / min, and the roller surface temperature is maintained at -80 to -120℃.

4. The method for preparing low-temperature anti-oxidation samples of highly active rare earth alloys according to claim 1, characterized in that, In step (3), when the vacuum pressure reaches -0.095MPa, the vacuum pump and vacuum solenoid valve are turned off, and the manual valve set on the vacuum drain is prompted to be closed manually. After manual confirmation, the vacuum pressure holding process begins. After the vacuum pressure holding process is completed, the manual valve set on the inert gas drain is prompted to be opened manually. After manual confirmation, the inert gas solenoid valve is opened to fill argon gas, and the oxygen content is detected synchronously through the oxygen content detection unit set on the bypass sampling branch. If the oxygen content is ≤0.8%, close the inert gas solenoid valve and start argon charging and pressure holding; If the oxygen content does not meet the standard and the argon filling pressure reaches the preset filling pressure threshold, the inert gas solenoid valve will be closed and the next replacement cycle will begin.

5. The method for preparing low-temperature anti-oxidation samples of highly active rare earth alloys according to claim 1, characterized in that, In step (4), the low-temperature stepped grinding includes a rapid pre-cooling stage, a stepped speed-up stage, and a stable grinding stage. In the rapid pre-cooling stage, the grinding speed is 300 rpm and the grinding temperature is cooled to -45℃. In the stepped speed-up stage, the grinding speed is gradually increased from 300 rpm to 400 rpm and the grinding temperature is maintained at -45℃±1℃. In the stable grinding stage, the grinding speed is 400 rpm and the grinding temperature is maintained at -45℃.

6. An online monitoring device for gas replacement in a grinding jar used for low-temperature oxidation prevention of high-activity rare earth alloy samples, characterized in that, It includes a dual-row tube body, a vacuum pumping passage, an inert gas filling passage, and an end-of-line bypass sampling and monitoring component; The dual-row pipe body includes a vacuum row and an inert gas row. The inert gas row has multiple grinding tank interfaces for connecting to the grinding tank and an exhaust port located at the end of the inert gas row. The vacuum pumping passage is connected to the vacuum drain, and the inert gas filling passage is connected to the inert gas drain; The end bypass sampling monitoring component includes a diversion connector disposed at the exhaust port, a bypass sampling branch connected to the diversion connector, and an oxygen content detection unit disposed on the bypass sampling branch. The diversion connector is used to allow a portion of the exhaust gas from the exhaust port to be discharged along the main exhaust direction, while the other portion enters the bypass sampling branch, so that the oxygen content detection unit can perform online oxygen content detection on the replacement gas that flows from the multiple grinding tank interfaces to the exhaust port.

7. The online monitoring device for gas replacement in grinding tanks according to claim 6, characterized in that, The bypass sampling branch is provided with a one-way valve, a buffer flow stabilizer, a flow control display component, an oxygen content detection unit, and an exhaust gas barrier component in sequence along the airflow direction.

8. The online monitoring device for gas replacement in grinding tanks according to claim 7, characterized in that, The buffer flow stabilizer is a buffer bottle, the flow control display component includes a rotor flow meter and / or a flow regulating valve, the rotor flow meter is used to display the gas flow rate of the bypass sampling branch, the flow regulating valve is used to regulate the gas flow rate of the bypass sampling branch, the tail gas barrier is a water seal bottle, and the oxygen content detection unit includes an oxygen content sensor flow cell and an oxygen sensor disposed in the oxygen content sensor flow cell.

9. The online monitoring device for gas replacement in a grinding tank according to claim 7 or 8, characterized in that, The one-way valve, buffer flow stabilizer, and exhaust gas barrier together constitute an anti-backflow structure to prevent external gas or liquid from entering the inert gas discharge via the bypass sampling branch.

10. The online monitoring device for gas replacement in a grinding tank according to claim 6, characterized in that, It also includes an intelligent monitoring and alarm module, which is electrically connected to the oxygen content detection unit and configured to output a prompt signal or alarm signal based on the oxygen content detected by the oxygen content detection unit; The intelligent monitoring and alarm module is also electrically connected to the pressure detection unit, which is used to detect the pressure inside the dual-row pipe body. The intelligent monitoring and alarm module is configured to perform a linkage prompt or linkage alarm based on the pressure value detected by the pressure detection unit and the oxygen content detected by the oxygen content detection unit. The vacuum stack is equipped with a pressure detection port, and the pressure detection unit is connected to the pressure detection port; The vacuum outlet is provided with a vacuum inlet. The vacuum pumping passage includes a vacuum pump, a filter, and a vacuum control valve connected in sequence. The vacuum control valve is connected to the vacuum inlet. The inert gas charging passage includes an inert gas source, a pressure reducing valve, a one-way valve, and a charging control valve connected in sequence. The charging control valve is connected to the inert gas outlet.

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