阅读说明：本技术 一种颗粒氢化镁的制造方法 (Method for preparing granular magnesium hydride ) 是由 俞强 于 2021-09-23 设计创作，主要内容包括：本发明公开了一种颗粒氢化镁的制造方法,包括如下步骤：将镁为主要成分的原料制造镁粉；将镁粉压制标准镁颗粒；在惰性气体保护下对标准镁颗粒进行高低温脆化,使标准镁颗粒产生更多的微裂纹,增大比表面积,形成颗粒镁胚；将颗粒镁胚与氢气反应生成氢化镁颗粒。该颗粒氢化镁的制造方法,先通过镁粉压制形成多孔的标准镁颗粒,然后采用了物理加热然后再急速冷却使标准镁颗粒产生微裂纹以增大比表面积的工艺,使得颗粒镁胚与氢气的接触充分,提高生成氢化镁的速率,且使所选用的镁粉的尺寸可以较大,以降低成本,同时,同时更大的镁粉粒径尺寸意味着更低的粉尘爆炸风险,提高了加工的安全性。(The invention discloses a method for manufacturing granular magnesium hydride, which comprises the following steps: preparing magnesium powder from raw materials with magnesium as a main component; pressing magnesium powder into standard magnesium particles; carrying out high-low temperature embrittlement on standard magnesium particles under the protection of inert gas, so that more microcracks are generated on the standard magnesium particles, the specific surface area is increased, and a particle magnesium blank is formed; reacting the magnesium blank with hydrogen to produce magnesium hydride particles. According to the manufacturing method of the granular magnesium hydride, the porous standard magnesium granules are formed by pressing magnesium powder, then the technology that microcracks are generated on the standard magnesium granules to increase the specific surface area is adopted, the contact between the granular magnesium blank and hydrogen is sufficient, the speed of generating magnesium hydride is improved, the size of the selected magnesium powder can be larger, the cost is reduced, meanwhile, the larger particle size of the magnesium powder means the lower dust explosion risk, and the processing safety is improved.)

1. A method for producing particulate magnesium hydride, comprising the steps of:

firstly, preparing magnesium powder from raw materials with magnesium as a main component;

secondly, pressing magnesium powder into standard magnesium particles;

performing high-low temperature embrittlement on the standard magnesium particles under the protection of inert gas, so that more microcracks are generated on the standard magnesium particles, the specific surface area is increased, and a particle magnesium blank is formed;

and (IV) reacting the magnesium blank particles with hydrogen to generate magnesium hydride particles.

2. The method for producing a particulate magnesium hydride according to claim 1, wherein: the particle size of the magnesium powder is between 150 and 250 microns.

3. The method for producing a particulate magnesium hydride according to claim 1, wherein: the density of the granular magnesium embryo is less than 1.5g/cm³。

4. The method for producing a particulate magnesium hydride according to claim 1, wherein: the shapes of the granular magnesium blank comprise a sphere, a cuboid, a cylinder and a hexahedron.

5. The method for producing a particulate magnesium hydride according to claim 1, wherein: in the step (III), the high-low temperature embrittlement process comprises the following steps: firstly, baking standard magnesium particles in an oven under the protection of inert gas, then quickly introducing low-temperature inert gas into the standard magnesium particles, and enabling the standard magnesium particles to generate a large number of microcracks through high-temperature and low-temperature alternation.

6. The method for producing a particulate magnesium hydride according to claim 1, wherein: the magnesium powder in the step (I) is prepared by adopting an ultrasonic smashing molten metal powder preparation process.

Technical Field

The invention relates to the field of magnesium hydride manufacturing, in particular to a method for manufacturing granular magnesium hydride.

Background

Magnesium hydride (MgH)₂) The grey white powder is single light metal hydride, has high stability at normal temperature and normal pressure, density of 1.45g/cm3 and hydrogen storage amount of 7.6%, and is far higher than magnesium-based hydrogen storage alloy hydride and other metal hydrides. Magnesium hydride may react with water at ambient temperature to produce hydrogen. And can also be used as a catalyst, a reducing agent and the like.

The following methods are available for the production of magnesium hydride: 1. the nano magnesium powder and hydrogen are combined to generate the hydrogen-rich magnesium alloy in a high-temperature and high-pressure environment, and the nano magnesium powder is used, so that the production cost is high, and the yield is low; 2. compared with the reaction of nano magnesium powder and hydrogen, the method has lower cost, but requires a large amount of energy consumption and time for grinding, has higher production cost and cannot produce magnesium hydride on a large scale.

The other method is to use mechanical processing method under normal state, firstly, the metal magnesium is cut into magnesium chips with certain size, the contradiction between dust explosion and the largest specific area and easier reaction with hydrogen is effectively balanced by the size of the magnesium chips, then the magnesium chips are pressed into magnesium blanks, and the magnesium blanks react with hydrogen in a hydrogenation furnace at high temperature and high pressure to generate magnesium hydride. The method needs mechanical processing of the magnesium blank, the processing size of the magnesium blank needs to be in the range of mu m, the processing efficiency is low, the cost is high, and potential safety hazards exist.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a method for manufacturing granular magnesium hydride, which solves the problems in the background art.

In order to achieve the purpose, the invention is realized by the following technical scheme: a method of making particulate magnesium hydride comprising the steps of:

firstly, preparing magnesium powder from raw materials with magnesium as a main component;

secondly, pressing magnesium powder into standard magnesium particles;

performing high-low temperature embrittlement on the standard magnesium particles under the protection of inert gas, so that more microcracks are generated on the standard magnesium particles, the specific surface area is increased, and a particle magnesium blank is formed;

and (IV) reacting the magnesium blank particles with hydrogen to generate magnesium hydride particles.

Further defined, the particle size of the magnesium powder is between 150 and 250 microns.

Further defined, the density of the particulate magnesium embryo is less than 1.5 g/cm.

Further defined, the shape of the granular magnesium blank comprises a sphere, a cuboid, a cylinder and a hexahedron.

Further limiting, in the step (three), the high-low temperature embrittlement process is as follows: firstly, baking standard magnesium particles in an oven under the protection of inert gas, then quickly introducing low-temperature inert gas into the standard magnesium particles, and enabling the standard magnesium particles to generate a large number of microcracks through high-temperature and low-temperature alternation.

Further limiting, the preparation of the magnesium powder in the step (I) adopts a process of crushing molten metal into powder by ultrasonic waves.

The invention has the following beneficial effects: according to the manufacturing method of the granular magnesium hydride, the porous standard magnesium granules are formed by pressing magnesium powder, then the technology that microcracks are generated on the standard magnesium granules to increase the specific surface area is adopted, the contact between the granular magnesium blank and hydrogen is sufficient, the speed of generating magnesium hydride is improved, the size of the selected magnesium powder can be larger, the cost is reduced, meanwhile, the larger particle size of the magnesium powder means the lower dust explosion risk, and the processing safety is improved.

Drawings

FIG. 1 is a flow chart of the preparation of the present invention;

FIG. 2 is a schematic representation of a particulate magnesium embryo of the present invention;

FIG. 3 is a schematic representation of a standard magnesium particle of the present invention;

FIG. 4 shows Mg and MgH in the production of magnesium hydride according to the invention₂The equilibrium graph.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 4, the formation of particulate magnesium hydride is based on the well-known principle curve of magnesium hydride formation, i.e., hydrogen gas will produce stable magnesium hydride at one temperature and pressure and will decompose into magnesium and hydrogen gas at the other side of the curve.

Referring to fig. 1, in the first embodiment: the invention discloses a method for manufacturing granular magnesium hydride, which comprises the following steps:

1. magnesium powder is manufactured, wherein magnesium is used as a raw material of a main component, the magnesium powder is prepared by a process of crushing molten metal powder by ultrasonic waves, the particle size of the magnesium powder is required to be larger than 150 micrometers to ensure processing safety and avoid explosion risks caused by dust, and meanwhile, the particle size of the magnesium powder is required to be smaller than 250 micrometers to ensure a large enough specific surface area and hydrogen reaction;

2. the standard magnesium particles are pressed by magnesium powder, other metal powder such as iron powder, calcium powder and the like can be added into the magnesium powder before pressing to improve the hydrogen release performance of the magnesium hydride particles, and finally porous stable granular standard magnesium particles shown in figure 3 are formed, wherein the size of the standard magnesium particles can be various forms and sizes, the diameter of the standard magnesium particles can be more than 3mm, the standard magnesium particles can be various required shapes such as spheres, cuboids, hexahedrons and the like according to actual requirements, and the density of the standard magnesium particles is required to be less than 1.5g/cm³So as to ensure that the clearance between the magnesium powder is ensured to the maximum extent in the compression process, and the hydrogen can contact with the magnesium to the maximum extent and generate magnesium hydride;

3. performing high-low temperature embrittlement, namely baking standard magnesium particles in an oven under the protection of inert gas, then quickly introducing low-temperature inert gas into the standard magnesium particles, and performing high-low temperature alternation to generate a large number of microcracks on the standard magnesium particles and increase the specific surface area to form a particle magnesium blank shown in figure 2, wherein the inert gas can be one or the combination of more of helium, neon, argon, krypton and xenon.

4. The method comprises the following steps that a particle magnesium blank enters a hydrogenation furnace, and reacts with hydrogen in the hydrogenation furnace to generate magnesium hydride particles, the hydrogenation process in the hydrogenation furnace is divided into two process stages, wherein in the first process stage, the temperature and the pressure are increased, and the hydrogen and the particle magnesium blank are positioned on one side of a curve which cannot produce magnesium hydride, so that the hydrogen reduces a small amount of magnesium oxide shells on the surfaces of the magnesium particles; after the above-mentioned process is completed, regulating temperature and pressure and returning to one side of curve capable of producing stable magnesium hydride material, after the catalytic reaction of temperature and pressure, the heat quantity produced by combining magnesium hydride can retain further reaction of hydrogen gas and granular magnesium, and after the heat-insulating and pressure-maintaining processes are continued for a period of time, the produced purity of magnesium hydride granules can meet the required requirements.

Cutting, pressing, hydrogenating and secondarily crushing are needed in a normal state. The mechanical processing energy consumption of the whole process is high, and the process is complex. The new invention improves the technology of mechanically processing the magnesium blank under normal conditions and then carrying out the manufacture of magnesium hydride. The new invention prepares fine powder with the particle size meeting the maximum specific surface area for reaction with hydrogen and the granularity above the dust explosion critical by improving the process and canceling the mechanical cutting link and using an industrial metal physical powder preparation method, and prepares the standard porous magnesium particles by subdividing and pressing the fine powder into the required shapes of a ball star, a cuboid, a column and the like by a standardized particle pressing process.

In order to ensure that the generated magnesium particles have a large enough specific surface area, the pressed porous standard magnesium particles firstly enter a high-temperature oven under the protection of inert gas, are heated to the temperature of between 50 and 200 ℃, then are moved into a cold box under the protection of the inert gas, and are rapidly cooled by using inert cold gas at the temperature of less than minus 20 ℃, so that the process causes a large number of secondary microcracks to be generated on particles forming the magnesium particles, thereby increasing the specific surface area of the reaction.

The method can further increase the particle size of the magnesium powder for pressing and further reduce the production cost. Because the heating and the rapid cooling are integrated operations, the industrial scale production can be carried out. And (4) loading the standard magnesium particles by using a standard container, and then, feeding the standard magnesium particles into a hydrogenation furnace for hydrogenation to prepare the granular magnesium hydride. The magnesium hydride discharged from the furnace can be used without any secondary processing. The process greatly shortens the production process of magnesium hydride. The production cost of the magnesium hydride is reduced. Meanwhile, the consistency of magnesium hydride particles is improved, and the stability, safety and controllability of a subsequent hydrogen release device are guaranteed.

The invention further reduces the production cost of the magnesium hydride and reduces the mechanical processing links. The magnesium powder and magnesium powder pressed particles can be produced in the existing industrial system in a large scale and at low cost, so that the production cost of the magnesium hydride particles is reduced;

the invention makes the magnesium hydride in standard particle form, the production process can be standardized, and the consistency of the generated magnesium hydride can be completely guaranteed. In the process of using magnesium hydride in batch industry, the stability of the magnesium hydride is improved, and the stability and the reliability of the whole hydrogen generating system are further improved.

The invention adopts the process of generating microcracks by physical heating and then rapidly cooling to increase the specific surface area, so that the size of the selected magnesium powder can be larger, the production cost is further reduced in the process, and meanwhile, the larger particle size of the magnesium powder means lower dust explosion risk, and the processing safety is improved.

The invention cancels the secondary crushing process of the massive magnesium hydride, further reduces the cost and avoids the waste in the crushing process.

It should be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.