Composite hydrogen storage material based on invalid hydrogen storage alloy powder and preparation method thereof

Abstract

The invention discloses a composite hydrogen storage material based on invalid hydrogen storage alloy powder and a preparation method thereof.The preparation method comprises the following steps that waste hydrogen storage powder alloy blocks are crushed in an inert atmosphere under the hammer type impact effect, the impact pressure is 10-90 MPa, and the waste hydrogen storage powder alloy blocks form mechanical tablets while being crushed; and after the crushed powdered alloy is screened, the crushed powdered alloy is uniformly mixed with an aerosol lubricant in proportion, and the mixing process is carried out in an inert atmosphere. The aerosol lubricant and the treated and recycled hydrogen storage alloy are used for preparing the composite hydrogen storage material, so that the powder fluidity is improved, crushing, compaction and stress accumulation in the circulation process are reduced, the resource utilization rate is increased, and environmental pollution is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of hydrogen storage alloy materials, and specifically provides a composite hydrogen storage material based on spent hydrogen storage alloy powder and a preparation method thereof. Background Art

[0002] The statements herein merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] Hydrogen energy has a very broad application market in vehicle-mounted and energy storage due to its green, safe, efficient and sustainable characteristics. Safe hydrogen storage is one of the key technologies to realize the utilization of hydrogen energy. Hydrogen storage alloys have large hydrogen absorption capacity and mild conditions. In addition, my country has abundant reserves of nickel and rare earths, so the industrialization prospects of hydrogen storage alloys are optimistic. At present, the hydrogen storage alloys with relatively mature research systems mainly include rare earth hydrogen storage alloys (AB5 type), Laves phase hydrogen storage alloys (AB2 type), Ti-Fe hydrogen storage alloys (AB type) and Mg hydrogen storage alloys (A2B type).

[0004] However, during the process of hydrogen absorption and desorption, the large expansion and contraction of the metal lattice in the hydrogen storage alloy, as well as the cracks and residual thermal stress inside the alloy, will cause the alloy to pulverize rapidly after hydrogen absorption. After several cycles of hydrogen absorption and desorption, the hydrogen storage alloy is pulverized into powders ranging from several microns to tens of microns. After the alloy is pulverized, under the action of gravity and expansion stress, it accumulates in the middle and lower parts of the hydrogen storage reaction bed and forms blocks, which directly leads to the expansion, plastic deformation and failure of the reaction bed. Increasing the wall thickness of the reaction bed is the most direct way to improve the structural strength of the bed, but relying on increasing the wall thickness to improve the reliability of the bed is not only costly, but also has negative effects on self-weight and heat transfer. In addition, the porosity of the compacted hydrogen storage alloy gradually decreases, and the process of hydrogen atoms continuing to diffuse into the alloy is hindered, making it difficult for the internal alloy to be hydrogenated. At the same time, the increase in the size of the hydrogen storage alloy may cause hydrogen atoms to need to overcome a higher energy barrier height during the diffusion process, which directly affects the heat transfer and mass transfer performance of the hydrogen storage alloy, resulting in the so-called alloy failure and even the filled reaction bed being abandoned.

[0005] In addition, the main components of hydrogen storage alloy waste powder are Ni, La, etc., which are all precious metal elements. Most of them are sold at low prices or directly discarded. This not only causes a waste of resources, but also the heavy metals in it will pollute the surrounding environment.

[0006] A small amount of hydrogen storage alloy waste powder can be recycled by pyrometallurgy or hydrometallurgy, which can improve the recycling rate of alloy elements. The process is simple and reasonable, the process is easy to control, and a large amount of precious metal element resources can be saved. However, the recycling method based on hydrometallurgy has low added value and brings secondary pollution of acid and alkali, while the method based on pyrometallurgy has high energy consumption and serious pollution. Moreover, neither of these two methods fully utilizes the advantages of the powdered alloy block being dense and difficult to crush. Summary of the invention

[0007] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a composite hydrogen storage material based on spent hydrogen storage alloy powder and a preparation method thereof. The present invention prepares a composite hydrogen storage material by combining an aerosol lubricant with a treated recycled hydrogen storage alloy to improve powder fluidity, thereby reducing crushing, compaction and stress accumulation during the circulation process, improving resource utilization, and reducing environmental pollution.

[0008] In order to achieve the above object, the present invention is implemented through the following technical solutions:

[0009] In a first aspect, the present invention provides a method for preparing a composite hydrogen storage material based on spent hydrogen storage alloy powder, comprising the following steps:

[0010] The waste hydrogen storage powdered alloy blocks are crushed by hammer impact in an inert atmosphere, and the impact pressure is 10-90MPa. The waste hydrogen storage powdered alloy blocks are crushed and mechanically pressed into tablets at the same time;

[0011] The crushed powdered alloy is sieved and then mixed with the aerosol lubricant in proportion, and the mixing process is carried out in an inert atmosphere.

[0012] Mechanical tableting refers to a collection of particles of a certain size, similar to a pile of powder compacted under high pressure into a flat block. In order to relieve the stress caused by the expansion and contraction of the alloy during the alloy hydrogenation process of the reaction bed, tableting the alloy powder is an effective solution, and powder does not have this effect.

[0013] In some embodiments, the waste hydrogen storage powdered alloy blocks are cut and taken out from the waste reaction bed and then sealed in a sealed bag for storage.

[0014] In some embodiments, the waste hydrogen storage pulverized alloy blocks are crushed using a reversible hammer crusher.

[0015] In some embodiments, the crushed powdered alloy is screened using a double-layer vibrating screen, with the upper screen opening being 4 mm and the lower screen opening being 3 mm, to discard larger and smaller alloy agglomerates.

[0016] In some embodiments, the mass ratio of the crushed powdered alloy to the aerosol lubricant is 99-1991:1.

[0017] Preferably, the aerosol lubricant is Aerosil R805 or Aerosil R972.

[0018] Aerosil R805 and Aerosil R972 are Degussa fumed silica white carbon black.

[0019] In some embodiments, when the crushed pulverized alloy is mixed with the aerosol lubricant, the mixture is initially mixed and then mixed in a rotating drum. This mixing method can effectively improve the mixing uniformity and will not cause significant damage to the crushed pulverized alloy.

[0020] Preferably, when mixing in a rotating drum, the rotating drum is rotated at 4-6 rpm for 50-100 revolutions for mixing.

[0021] In some embodiments, during the treatment process of the discarded hydrogen storage powdered alloy block and the crushed powdered alloy, the O2 content in the atmosphere is less than 5ppm and the H2O content is less than 1ppm.

[0022] In a second aspect, the present invention provides a composite hydrogen storage material based on spent hydrogen storage alloy powder, which is prepared by the preparation method.

[0023] The beneficial effects achieved by one or more embodiments of the present invention are as follows:

[0024] The agglomerates of the powdered alloy densified by stress accumulation (about tens of MPa) are crushed and screened by the present method to form mechanical tablets similar to hydrogen storage alloys (the compaction pressure is about tens of MPa) with stable properties.

[0025] When the powdered alloy blocks are recycled, the cohesive force inside the powdered alloy is greater than the expansion stress, and it is not easy to crush itself again. In addition, the aerosol lubricant powder initially exists in the form of agglomerates and is decomposed into smaller aggregates during the mixing process. These smaller aggregates are adsorbed on the surface of the powdered alloy blocks, which reduces the total contact area between the powdered alloy blocks and weakens the van der Waals force, thereby improving the fluidity of the alloy blocks and effectively limiting their further discrete aggregation.

[0026] The inherent compaction and anti-powdering properties of the pulverized alloy block will significantly reduce the local expansion stress of the hydrogen storage reaction bed, and also have the characteristics of reducing strain accumulation and enhancing heat transfer. The efficient recycling of the modified spent hydrogen storage alloy powder is also of great significance to the protection of rare earth deposits. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0028] Figure 1 This is a flow chart of preparing a composite hydrogen storage material for reusing hydrogen storage alloy powder by adding a lubricant according to Example 1 of the present invention;

[0029] Figure 2 This is a schematic diagram of loading a composite hydrogen storage material for reusing hydrogen storage alloy powder by adding a lubricant according to Example 1 of the present invention;

[0030] Figure 3 This is a specific flow chart for preparing a composite hydrogen storage material by adding a lubricant to reuse the hydrogen storage alloy powder according to Example 1 of the present invention. DETAILED DESCRIPTION

[0031] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0032] The present invention will be further described below in conjunction with the embodiments.

[0033] Example 1

[0034] A method for preparing a composite hydrogen storage material by adding a lubricant to reuse hydrogen storage alloy powder, see Figure 1 ,include:

[0035] Step 1: Recovery of hydrogen storage powdered alloy blocks:

[0036] 11) Cutting and removing the powdered alloy blocks from the abandoned reaction bed;

[0037] 12) The cut powdered alloy blocks are sealed and stored in a sealed bag;

[0038] 13) All material processing was carried out in a controlled argon-filled glove box;

[0039] Step 2: Crushing of hydrogen storage powder alloy blocks:

[0040] The powdered alloy powder blocks recovered in step 1 are continuously and evenly fed into the crushing chamber of a reversible hammer crusher for fine crushing. The pressure applied by the crusher to the powdered alloy blocks is 60 MPa. This process is carried out in an argon-filled glove box.

[0041] The crushed powdered alloy was placed in an argon-filled glove box with a double-layer vibrating screen (upper sieve hole ~4mm, lower sieve hole ~3mm) for sieving. The weight of a single piece was about 5 to 30 mg, and larger and smaller alloys were discarded.

[0042] Step 3: Loading of composite hydrogen storage materials:

[0043] The powdered alloy and lubricant Aerosil R 805 with a mass ratio of 99:1 were hand-shaken in a volumetric flask, and then rotated in a rotating drum at 4.5 rpm for about 50 turns. All material processing was carried out in a controlled argon-filled glove box (<5 ppm O2 and <1 ppm H2O).

[0044] Schematic diagram of the structure of the prepared composite hydrogen storage material, such as Figure 2 As shown, the powdered alloy 1 itself is similar to a mechanical tablet because of its densification, and its internal cohesive force is greater than the expansion stress, and it is not easy to be crushed again. After the powdered alloy is evenly mixed with the nano-silicon dioxide powder, the nano-silicon dioxide powder 2 is adsorbed on the surface of the powdered alloy block 1, thereby reducing the van der Waals force by increasing the roughness of the surface of the powdered alloy block 1, effectively limiting its re-powdering and deposition, realizing the reuse of the powdered alloy, and improving resource utilization. The alloy hydrogen absorption and desorption cycle test 50 times shows that the stability of the alloy sheet is good.

[0045] Example 2

[0046] A method for preparing a composite hydrogen storage material by adding a lubricant to reuse hydrogen storage alloy powder, see Figure 1 ,include:

[0047] Step 1: Recovery of hydrogen storage powdered alloy blocks:

[0048] 11) Cutting and removing the powdered alloy blocks from the abandoned reaction bed;

[0049] 12) The cut powdered alloy blocks are sealed and stored in a sealed bag;

[0050] 13) All material processing was carried out in a controlled argon-filled glove box;

[0051] Step 2: Crushing of hydrogen storage powder alloy blocks:

[0052] The powdered alloy powder blocks recovered in step 1 are continuously and evenly fed into the crushing chamber of a reversible hammer crusher for fine crushing. The pressure applied by the crusher to the powdered alloy blocks is 70 MPa. This process is carried out in an argon-filled glove box.

[0053] The crushed powdered alloy was placed in an argon-filled glove box with a double-layer vibrating screen (upper sieve hole ~4mm, lower sieve hole ~3mm) for sieving. The weight of a single piece was about 5 to 30 mg, and larger and smaller alloys were discarded.

[0054] Step 3: Loading of composite hydrogen storage materials:

[0055] The powdered alloy and lubricant Aerosil R972 with a mass ratio of 1991:1 were hand-shaken in a volumetric flask, and then rotated in a rotating drum at 4.5 rpm for about 50 turns. All material processing was carried out in a controlled argon-filled glove box (<5 ppm O2 and <1 ppm H2O).

[0056] Schematic diagram of the structure of the prepared composite hydrogen storage material, such as Figure 2 As shown, the powdered alloy 1 itself is similar to a mechanical tablet because of its densification, and its internal cohesive force is greater than the expansion stress, and it is not easy to be crushed again. After the powdered alloy is evenly mixed with the nano-silicon dioxide powder, the nano-silicon dioxide powder 2 is adsorbed on the surface of the powdered alloy block 1, thereby reducing the van der Waals force by increasing the roughness of the surface of the powdered alloy block 1, effectively limiting its re-powdering and deposition, realizing the reuse of the powdered alloy, and improving resource utilization. The alloy hydrogen absorption and desorption cycle test 50 times shows that the stability of the alloy sheet is good.

[0057] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing a composite hydrogen storage material based on spent hydrogen storage alloy powder, characterized in that: The steps include: The waste hydrogen storage powdered alloy blocks are crushed by hammer impact in an inert atmosphere, and the impact pressure is 10-90MPa. The waste hydrogen storage powdered alloy blocks are crushed and mechanically pressed into tablets at the same time; The crushed powdered alloy is sieved and then mixed with the aerosol lubricant in proportion, and the mixing process is carried out in an inert atmosphere.

2. The method for preparing a composite hydrogen storage material based on spent hydrogen storage alloy powder according to claim 1, characterized in that: The waste hydrogen storage powdered alloy blocks are cut and taken out from the waste reaction bed and then sealed in a sealed bag for storage.

3. The method for preparing a composite hydrogen storage material based on spent hydrogen storage alloy powder according to claim 1, characterized in that: The waste hydrogen storage powdered alloy blocks are crushed by a reversible hammer crusher.

4. The method for preparing a composite hydrogen storage material based on spent hydrogen storage alloy powder according to claim 1, characterized in that: The crushed powdered alloy is screened using a double-layer vibrating screen, with the upper screen hole being 4 mm and the lower screen hole being 3 mm.

5. The method for preparing a composite hydrogen storage material based on spent hydrogen storage alloy powder according to claim 1, characterized in that: The mass ratio of the crushed powdered alloy to the aerosol lubricant is 99-1991:

1.

6. The method for preparing a composite hydrogen storage material based on spent hydrogen storage alloy powder according to claim 1, characterized in that: The aerosol lubricant is Aerosil R805 or Aerosil R972.

7. The method for preparing a composite hydrogen storage material based on spent hydrogen storage alloy powder according to claim 1, characterized in that: When the crushed powdered alloy is mixed with the aerosol lubricant, after preliminary mixing, the mixture is mixed in a rotating drum.

8. The method for preparing a composite hydrogen storage material based on spent hydrogen storage alloy powder according to claim 7, characterized in that: When mixing in a rotating drum, the mixing is performed by rotating the drum at 4-6 rpm for 50-100 revolutions.

9. The method for preparing a composite hydrogen storage material based on spent hydrogen storage alloy powder according to claim 1, characterized in that: During the treatment process of the waste hydrogen storage powdered alloy blocks and the crushed powdered alloy, the O2 content in the atmosphere is less than 5ppm and the H2O content is less than 1ppm.

10. A composite hydrogen storage material based on spent hydrogen storage alloy powder, characterized in that: Prepared by the preparation method described in any one of claims 1 to 9.

Images