A device and method for preparing high-toughness hydrogen storage alloy low-defect ultrafine powder

Abstract

The present invention discloses a device and method for preparing a strong and tough hydrogen storage alloy low-defect ultrafine powder, which belongs to the technical field of hydrogen storage materials. The alloy powder prepared by the device has uniform particle size distribution, easy to control particle size, few lattice defects, not easy to oxidize, no dust pollution, significantly improves the efficiency of strong and tough alloy powder making, reduces the poisoning of the material powder making process, and improves the cycle stability.

Description

Technical Field

[0001] The invention belongs to the technical field of hydrogen storage materials, and in particular relates to a device and a method for preparing a high-toughness hydrogen storage alloy low-defect ultrafine powder. Background Art

[0002] Titanium-vanadium, ZrCo and other hydrogen storage alloys have the advantages of high hydrogen storage capacity and the ability to absorb and desorb hydrogen at near normal temperature and pressure. They are expected to become a new generation of solid-state hydrogen storage materials for large-scale applications. However, due to the solid solution structure of such hydrogen storage alloys, they often show strong toughness and are difficult to directly powderize using conventional mechanical crushing methods like brittle intermetallic compounds such as LaNi5 and TiMn2. Mechanical action can easily introduce a large number of lattice defects, thereby deteriorating the hydrogen storage performance. In addition, studies have shown that the cyclic stability of hydrogen storage alloys in the absorption and desorption of hydrogen is significantly affected by the particle size and degree of distortion of the alloy powder. Ultrafine powders with low defects often show better cyclic stability. Therefore, it is a key technical problem to be solved urgently to develop efficient and clean powdering technology for high-strength and tough hydrogen storage alloys and obtain ultrafine powders with low defects and controllable composition and particle size distribution.

[0003] Hydrogenation powder making is currently a more commonly used method for making strong and tough hydrogen storage alloys. This method is to control the hydrogen flow rate and reaction time at a certain temperature to achieve uniform solid solution of a certain amount of H, so that the matrix lattice expands and catalyzes and pulverizes. However, the powder particle size distribution obtained by this method is relatively wide, and multiple hydrogen absorption and desorption cycles or further mechanical ball milling are required to obtain alloy powders with smaller particle sizes. At the same time, hydrogen-induced distortion will also deteriorate the hydrogen storage performance of the alloy. The transfer process of the powder is also very likely to cause poisoning of the active alloy surface after hydrogenation, resulting in a decrease in the hydrogen storage performance of the alloy.

[0004] Therefore, in order to accelerate the large-scale application of strong and tough hydrogen storage alloys, it is crucial to develop a device and method for preparing low-defect ultrafine powders of strong and tough hydrogen storage alloys to address the problems of uneven particle size distribution of hydrogenated powder particles and prone to hydrogen-induced distortion, and the method of auxiliary mechanical ball milling after hydrogenation easily causing alloy poisoning.

[0005] In order to solve the problem that titanium-vanadium hydrogen storage alloy is hard and tough and difficult to crush, the embrittlement technology of the pre-hydrogenation process is adopted, combined with the controllable powder technology of low-temperature air flow mill, to develop a semi-continuous hydrogenation crushing-low-temperature air flow mill ultrafine powder clean preparation device and method, forming a hydrogen storage alloy ultrafine powder preparation technology with controllable particle size distribution and low defects. Summary of the invention

[0006] In order to solve the above problems, the present invention proposes a device for preparing ultrafine powder of strong and tough hydrogen storage alloy with low defects, including a hydrogenation system, a feeding system, a jet mill system and a control system;

[0007] A) Hydrogenation system:

[0008] The hydrogenation system comprises a hydrogenation tank (11) and a hydrogen tank (1), the hydrogenation tank (11) is connected to the hydrogen tank (1), and a feed port (15) is provided on the hydrogenation tank (11);

[0009] Controlling the opening and closing of the hydrogen tank (1) through the first valve;

[0010] Feeding system: the alloy block (7) is added into the hydrogenation tank (11) through the feeding port (15);

[0011] A temperature sensor (12), a pressure sensor (13) and a pressure gauge (14) are also provided in the hydrogenation tank (11) for monitoring the reaction environment in the tank;

[0012] The hydrogenation tank (11) is also connected to a vacuum pump (6); the vacuum pump (6) is used to control the vacuum degree in the hydrogenation tank (11), and the switch of the vacuum pump (6) is controlled by a valve III;

[0013] B) Feeding system:

[0014] The feed system comprises a gate valve (2) and a feeder (3); the bottom of a hydrogenation tank (11) of the hydrogenation system is connected to the feeder (3) via the gate valve (2); the feeder (3) contains a hydrogenated alloy block (8);

[0015] C) Jet Mill System:

[0016] The jet mill system comprises a feeder (31), a jet mill (32), an argon gas bottle (4), a gas precooler (41) and a gas compressor (42);

[0017] One end of the jet mill (32) is connected to the feeder (3) of the feeding system via the feeder (31), and the other end is connected to the argon gas bottle (4);

[0018] The airflow mill (32) is also provided with a vacuum pump; the vacuum pump is used to control the vacuum degree in the airflow mill (32) and the feeder (3), so as to ensure that the feeder (31) can transport the material in the feeder (3) to the airflow mill (32), and the switch of the vacuum pump is controlled by the valve II to obtain the powdering process alloy (9) in the airflow mill system;

[0019] By controlling the Vth valve, the gas in the argon gas cylinder (4) passes through the gas precooler (41) and the gas compressor (42) in sequence, and then enters the jet mill (32) through the IVth valve;

[0020] A temperature sensor (33) and a pressure sensor (34) are also provided in the airflow mill (32) for monitoring the internal reaction environment temperature and pressure;

[0021] The jet mill (32) is also connected to a collecting hopper (35) for collecting materials crushed by the jet mill (32);

[0022] D) Control system:

[0023] The control system comprises a control cabinet (5) and corresponding valve switches and monitoring equipment, and the closing of the valve and the parameters of the reaction environment (pressure, temperature, etc.) are controlled by the control cabinet (5).

[0024] The present invention also provides a method for preparing a device for preparing a high-toughness hydrogen storage alloy low-defect ultrafine powder, comprising the following steps:

[0025] 1) feeding the alloy raw material into the hydrogenation tank (11) through the feed port (15), then closing the feed port (15), turning on the vacuum pump (6), opening the valve III, performing a vacuum treatment on the hydrogenation tank (11), and then closing the valve III;

[0026] In the step 1), the alloy raw material is a strong and tough alloy ingot obtained by smelting, which is broken by wire cutting or mechanical impact to obtain an alloy block with a diameter less than 5 cm.

[0027] 2) heating the hydrogenation tank (11) to 100-200° C. and detecting the temperature of the hydrogenation tank (11) using a temperature sensor (12); opening the first valve of the hydrogen tank to allow hydrogen to be filled into the hydrogenation tank (11); closing the first valve and opening the third valve to perform a secondary vacuum treatment on the hydrogenation tank (11), and then cooling the hydrogenation tank (11) to room temperature.

[0028] 3) Open valve II and use a vacuum pump to evacuate the jet mill system. Then open the argon bottle (4) to allow argon to enter the jet mill system. Repeat the above operation to perform gas washing.

[0029] The vacuum degree of the first vacuum treatment and the second vacuum treatment in step 3) is ≥ 0.0001 MPa, and is maintained for 10 min to 2 h, preferably 10 to 60 min;

[0030] The pressure of the argon gas introduced in step 3) is 0.1 MPa;

[0031] Step 3) repeats the gas washing operation 2 to 3 times,

[0032] 4) opening the gate valve (2) to allow the hydrogenated and embrittled feed system alloy block (7) to enter the feeder (3), introducing argon gas to 0.05-1 MPa into the airflow mill system, and then opening the feeder (31) to transport the material into the airflow mill (32) at a feed rate of 0.5-5 kg / h; preferably, introducing argon gas to 0.1 MPa;

[0033] 5) Open the argon valve, valve IV and valve V, so that the argon gas first enters the gas precooler (41), is precooled to -30 ~ 10 ° C, and then the argon gas is compressed into the air mill (32) through the gas compressor (42); under the impact of the high-speed airflow, the alloy blocks in the air mill collide with each other quickly and break, and the crushed particles enter the collecting hopper (35) to be collected, thereby realizing a semi-continuous low-temperature powder making process.

[0034] In some preferred embodiments, the vacuum degree of step 1) the primary vacuum treatment and step 2) the secondary vacuum treatment is ≥ 0.0001 MPa, and is maintained for 10 min to 2 h, preferably 10 to 60 min.

[0035] In some preferred embodiments, the flow rate of hydrogen in step 2) is 2-10 mL / min / g; the hydrogen absorption amount of the hydrogen storage material in the hydrogenation tank is controlled to be 0.3-0.8 wt% and the inflation is stopped.

[0036] In some preferred embodiments, in the step 2), the hydrogenation tank is heated to a hydrogenation reaction temperature of 100-200°C.

[0037] In some preferred embodiments, the fan speed of the gas compressor (42) in step 5) is 1000-3500 rpm, and the gas flow rate is 200-500 m / s

[0038] The temperature of the argon gas is -30°C to 10°C; the flow rate of the argon gas is 200 to 500 m / s.

[0039] In some preferred embodiments, in step 5), argon gas is replaced with nitrogen gas.

[0040] The beneficial effects of the present invention are:

[0041] 1. The present invention discloses a method for preparing ultrafine powder of highly active and tough hydrogen storage alloy, which comprises pre-hydrogenation embrittlement treatment-inert atmosphere low-temperature air flow grinding powder treatment.

[0042] 2. The prepared alloy powder has uniform particle size distribution, easy to control particle size, few lattice defects, not easy to oxidize, and no dust pollution, which significantly improves the efficiency of strong and tough alloy powder making, reduces the toxicity of the material powder making process, and improves the cycle stability.

[0043] 3. The pre-hydrogenation embrittlement technology disclosed in the present invention reduces the high toughness and hard-to-break characteristics of the material itself through the hydrogen absorption and expansion effect of the material.

[0044] 4. The airflow milling equipment disclosed in the present invention can realize the transfer and milling of materials without contact with air after hydrogenation, thereby avoiding oxidation of highly active materials after hydrogenation due to contact with air.

[0045] 5. The low-temperature inert gas airflow grinding and powder making equipment disclosed in the present invention can realize defect-free and high-quality crushing of powder. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 .Schematic diagram of the structure of the hydrogenation-low temperature jet mill;

[0047] in:

[0048] Hydrogen tank 1, hydrogenation tank 11, temperature sensor 12, pressure sensor 13, pressure gauge 14, feed port 15;

[0049] Gate valve 2;

[0050] Feeder 3, feeder 31, jet mill 32, temperature sensor 33, pressure sensor 34, collection hopper 35;

[0051] Argon gas cylinder 4, gas precooler 41, gas compressor 42;

[0052] Control cabinet 5;

[0053] Vacuum pump 6;

[0054] Feeding system alloy block 7;

[0055] The alloy block 8 after hydrogenation in the feeder;

[0056] Powder making process in jet mill system Alloy 9;

[0057] Figure 2 .Macroscopic photo of the alloy block after the hydrogenation system reaction;

[0058] Figure 3 . Macroscopic photograph of the powder prepared by low-temperature jet milling after hydrogenation in Example 1;

[0059] Figure 4 . Microscopic morphology of powder prepared by low-temperature jet milling after hydrogenation in Example 1;

[0060] Figure 5 Example 1 Particle size distribution of powder prepared by low-temperature jet mill after hydrogenation;

[0061] Figure 6 .Example 1 Hydrogen absorption and desorption cycle performance diagram of powder prepared by low-temperature air flow mill after hydrogenation. DETAILED DESCRIPTION

[0062] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments:

[0063] Use Figure 1 The device shown is used to prepare ultrafine powder of strong and tough hydrogen storage alloy with low defects, and the steps are as follows:

[0064] 1) The cut alloy block is fed into the hydrogenation tank 11 through the feed port 15, and then the feed port 15 is closed, the vacuum pump 6 is turned on, the valve III is opened, and the hydrogenation tank is vacuumized. After the pressure in the hydrogenation tank is better than 0.0001 MPa, it is maintained for 10 to 60 minutes, and then the valve III is closed;

[0065] 2) After the hydrogenation tank is heated to a certain temperature (100-200° C.) and stabilized, the first valve of the hydrogen tank is opened, and a certain amount of hydrogen (corresponding to the hydrogen absorption of the hydrogen storage material of 0.3-0.8wt%) is charged at a certain flow rate (2-10mL / min / g); the hydrogen valve and the first valve are closed, the third valve is opened, and the vacuum is evacuated to a pressure better than 0.0001MPa, and after maintaining for 1-2h, the hydrogenation tank 11 is closed, heated, and cooled to room temperature;

[0066] 3) Open valve II, evacuate the jet mill system to a pressure better than 0.0001 MPa, maintain for 10 to 60 minutes, then introduce argon gas to the jet mill and feeder to a pressure of 0.1 MPa, evacuate again to a pressure better than 0.0001 MPa, repeat the above operation 2 to 3 times for gas washing;

[0067] 4) Open the gate valve 2 to allow the hydrogenated and embrittled alloy material to enter the airflow mill feeder 3, then close the gate valve. After argon is introduced into the feeder 3 and the airflow mill 32 to a pressure of 0.1 MPa, open the feeder 31 to transport the material into the airflow mill 32 at a feed rate of 0.5-5 kg / h;

[0068] 5) Open the argon valve, valve IV and valve V, and the gas first enters the gas precooler 41, where it is precooled to -30 to 10°C, and then passes through the gas compressor 42 to pressurize the low-temperature high-speed gas into the airflow mill 32, with a fan speed of 1000 to 3500 rpm and an airflow speed of 200 to 500 m / s. Under the impact of the high-speed airflow, the alloy blocks in the airflow mill collide with each other quickly and break, and the crushed particles enter the collecting hopper 35 to be collected, thereby realizing a semi-continuous low-temperature powder making process;

[0069] b) breaking the smelted tough alloy ingot by wire cutting or mechanical impact to obtain an alloy block with a diameter of less than 5 cm;

[0070] c) The block alloy prepared in step b is loaded into a hydrogenation tank device for pre-hydrogenation embrittlement treatment; the hydrogenation treatment conditions are as follows: the block alloy is laid flat in the sample chamber, the hydrogenation tank is heated to 100-200° C., hydrogen is slowly filled into the sample chamber at a rate of 2-10 mL / min / g, and the charging is stopped when the hydrogen absorption of the hydrogen storage material in the hydrogenation tank reaches 0.3-0.8 wt%, and the vacuum is evacuated to better than 0.0001 MPa and maintained for 1-2 hours, and then cooled to room temperature;

[0071] d) While step c is being carried out, wash the feeder and the jet mill equipment 2 to 3 times, and turn on the gas precooler to precool the argon gas entering the jet mill;

[0072] e) After closing the valve of the vacuum pump pipeline, open the gate to allow the hydrogenated and embrittled alloy block to enter the feeder, close the gate valve, and fill the feeder and the airflow mill with 0.05-1MPa argon. The alloy is fed into the airflow mill through the feeder at a feed rate of 0.5-5kg / h. The air compressor is turned on to perform low-temperature airflow milling of the alloy material particles obtained in step c under an inert atmosphere, with a fan speed of 1000rpm-3500rpm, a gas temperature of -30℃-10℃, and an airflow speed of 200-500m / s.

[0073] Example 1

[0074] A method for preparing ultrafine powder of strong and tough hydrogen storage alloy comprises the following steps:

[0075] (1) Using metal vanadium, metal titanium and metal chromium as raw materials, each metal raw material is prepared according to the stoichiometric ratio between the elements in the hydrogen storage alloy using a vacuum non-consumable arc furnace or a vacuum induction furnace, and the raw metals are smelted 3-5 times under an argon protective atmosphere to obtain V x Ti y Cr z Alloy ingot.

[0076] The obtained alloy ingot is cut into alloy blocks with a diameter less than 5 cm by wire cutting.

[0077] The cut alloy block was placed in a hydrogenation tank, and the hydrogenation tank was evacuated. When the pressure in the hydrogenation tank was better than 0.0001MPa, it was maintained for 60min. Then the hydrogenation tank was heated to 200℃, and hydrogen was slowly filled into the sample chamber at a rate of 5mL / min / g. When the hydrogen storage material in the hydrogenation tank absorbed 0.7wt%, the filling was stopped, and the vacuum was evacuated to better than 0.0001MPa and maintained for 2h, and then cooled to room temperature. After the hydrogenation reaction, the alloy material was Figure 2 shown.

[0078] After the hydrogenation reaction is completed, open the gate valve and transfer the hydrogenated material to the feeder at a feed rate of 5 kg / h. The material is crushed in a jet mill with an inlet temperature of -5 °C, a gas flow rate of 350 m / s, and an air compressor fan speed of 2500 rpm.

[0079] The crushed material is transported by the rising airflow and collected by the collecting hopper. Its macroscopic and microscopic appearance is as follows: Figure 3 and Figure 4 shown.

[0080] The prepared alloy powder has uniform particle size distribution ( Figure 5 ), easy to control particle size, few lattice defects, not easy to oxidize, no dust pollution, significantly improve the efficiency of strong and tough alloy powder making, reduce the toxicity of the material powder making process, and improve the cycle stability ( Figure 6 ).

Claims

1. A device for preparing ultrafine powder of strong and tough hydrogen storage alloy with low defects, comprising: Hydrogenation system, feeding system, jet mill system and control system; A) Hydrogenation system: The hydrogenation system comprises a hydrogenation tank (11) and a hydrogen tank (1), the hydrogenation tank (11) is connected to the hydrogen tank (1), and a feed port (15) is provided on the hydrogenation tank (11); Controlling the opening and closing of the hydrogen tank (1) through the first valve; Feeding system: the alloy block (7) is added into the hydrogenation tank (11) through the feeding port (15); A temperature sensor (12), a pressure sensor (13) and a pressure gauge (14) are also provided in the hydrogenation tank (11) for monitoring the reaction environment in the tank; The hydrogenation tank (11) is also connected to a vacuum pump (6); the vacuum pump (6) is used to control the vacuum degree in the hydrogenation tank (11), and the switch of the vacuum pump (6) is controlled by a valve III; B) Feeding system: The feed system comprises a gate valve (2) and a feeder (3); the bottom of a hydrogenation tank (11) of the hydrogenation system is connected to the feeder (3) via the gate valve (2); the feeder (3) contains a hydrogenated alloy block (8); C) Jet Mill System: The jet mill system comprises a feeder (31), a jet mill (32), an argon gas cylinder (4), a gas precooler (41) and a gas compressor (42); One end of the jet mill (32) is connected to the feeder (3) of the feeding system via the feeder (31), and the other end is connected to the argon gas bottle (4); The air flow mill (32) is also provided with a vacuum pump; the vacuum pump is used to control the vacuum degree in the air flow mill (32) and the feeder (3), so as to ensure that the feeder (31) can transport the material in the feeder (3) to the air flow mill (32), and the switch of the vacuum pump is controlled by the valve II to obtain the powdering process alloy (9) in the air flow mill system; By controlling the Vth valve, the gas in the argon gas cylinder (4) passes through the gas precooler (41) and the gas compressor (42) in sequence, and then enters the jet mill (32) through the IVth valve; A temperature sensor (33) and a pressure sensor (34) are also provided in the air flow mill (32); The jet mill (32) is connected to a collecting hopper (35) for collecting materials crushed by the jet mill (32); D) Control system: The control system comprises a control cabinet (5) and corresponding valve switches and monitoring equipment.

2. The method for preparing a device for preparing a strong and tough hydrogen storage alloy low-defect ultrafine powder according to claim 1 comprises the following steps: 1) feeding the alloy raw material into the hydrogenation tank (11) through the feed port (15), then closing the feed port (15), turning on the vacuum pump (6), opening the valve III, performing a vacuum treatment on the hydrogenation tank (11), and then closing the valve III; 2) heating the hydrogenation tank (11) to 100-200° C. and detecting the temperature of the hydrogenation tank (11) using a temperature sensor (12); opening the first valve of the hydrogen tank to allow hydrogen to be filled into the hydrogenation tank (11); closing the first valve and opening the third valve to perform a secondary vacuum treatment on the hydrogenation tank (11), and then cooling the hydrogenation tank (11) to room temperature; 3) Open valve II and use a vacuum pump to evacuate the jet mill system. Then open the argon bottle (4) to allow argon to enter the jet mill system. Repeat the above operation to perform gas washing. 4) opening the gate valve (2) to allow the hydrogenated and embrittled feed system alloy block (7) to enter the feeder (3), introducing argon gas into the jet mill system, and then opening the feeder (31) to transport the material into the jet mill (32); 5) Open the argon valve, valve IV and valve V, so that the argon gas first enters the gas precooler (41) and is precooled to -30~10°C. Then, the argon gas is compressed into the air flow mill (32) for reaction through the gas compressor (42); the crushed particles enter the collecting hopper (35) for collection, thereby realizing a semi-continuous low-temperature powder making process.

3. The preparation method according to claim 2, wherein In step 4), argon gas is introduced to a pressure of 0.05-1 MPa; The feed rate is 0.5~5kg / h.

4. The preparation method according to claim 2, wherein The vacuum degree of the step 1) the primary vacuum treatment and the step 2) the secondary vacuum treatment is ≥ 0.0001 MPa and is maintained for 10 min to 2 h.

5. The preparation method according to claim 2, wherein: The vacuum degree of the first vacuum treatment and the second vacuum treatment in step 3) is ≥ 0.0001 MPa, and is maintained for 10 min to 2 h; The pressure of the argon gas introduced in step 3) is 0.1 MPa; Repeat the gas washing operation 2 to 3 times in step 3).

6. The preparation method according to claim 2, wherein: In the step 2), the flow rate of hydrogen is 2-10 mL / min / g; the hydrogen absorption amount of the hydrogen storage material in the hydrogenation tank is controlled to be 0.3-0.8 wt% and the inflation is stopped.

7. The preparation method according to claim 2, wherein: In the step 2), the hydrogenation tank is heated to a hydrogenation reaction temperature of 100-200°C.

8. The preparation method according to claim 2, wherein: In step 5), the fan speed of the gas compressor (42) is 1000-3500 rpm, and the gas flow rate is 200-500 m / s.

9. The preparation method according to claim 2, wherein: In the step 5), the temperature of the argon gas is -30°C to 10°C; and the flow rate of the argon gas is 200 to 500 m / s.

10. The preparation method according to claim 2, wherein: In the step 5), argon gas is replaced with nitrogen gas.

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