Method for producing magnesium hydride

Abstract

This invention provides a method for efficiently producing one MgH2 (magnesium hydride) structure from one Mg compressed body made of raw materials mainly composed of magnesium. [Solution] A process to produce a magnesium-based hydride, in which a raw material mainly composed of magnesium is combined with hydrogen by reacting the components in a compressed Mg body with hydrogen gas in a hydrogen gas atmosphere under predetermined pressure and temperature ranges, is carried out by housing the compressed Mg body in a sealed reaction box equipped with a function to maintain the internal space pressure and internal space temperature under predetermined pressure and temperature ranges. Multiple reaction boxes in which the magnesium-based hydride production process is being carried out are brought into a reaction station, and the process of producing a magnesium-based hydride is carried out in the brought-in multiple reaction boxes while maintaining the internal space pressure and internal space temperature under predetermined pressure and temperature ranges.

Description

TECHNICAL FIELD

[0001] The present invention relates to a method for producing a magnesium-based hydride, which is formed by combining a magnesium-based raw material and hydrogen and is used for generating hydrogen through reaction with water. BACKGROUND ART

[0002] MgH₂ (magnesium hydride), which is a magnesium-based hydride formed by combining a magnesium-based raw material and hydrogen, is an ionic bonded hydride composed of a bond between Mg 2+ and H - similar to alkali metal hydrides, and is produced by reacting Mg (magnesium) with high-pressure hydrogen in a heated state. The reaction formula for producing MgH₂ is Mg+H₂ → MgH₂, as represented.

[0003] Although MgH₂ powder is charcoal gray and stable in air, it decomposes in water by reacting with water to release hydrogen. Therefore, MgH₂ that has absorbed hydrogen in advance can be used as a hydrogen storage material that releases hydrogen by reacting with water when needed.

[0004] The reaction formula for the reaction of MgH₂ with water is Pressure Temperature Water supply MgO 0.5×10 3 hPa 440°C 0.30kg / h 100% 1.0×10 3 hPa 470°C 0.27kg / h 100% 2.0×10 3 hPa 600°C 0.25kg / h 100% under the conditions of MgH₂+H₂O→MgO+2H₂ , as represented.

[0005] Note that Mg(OH)₂ is generated under normal temperature and normal pressure conditions MgH₂+2H₂O→Mg(OH)₂+2H₂ It is also known that the following hydrogen production reaction occurs.

[0006] As a by-product, MgO is more valuable and therefore more economically viable.

[0007] Various methods have been proposed for producing magnesium-based hydrides.

[0008] For example, Patent Document 1 proposes a method for producing magnesium-based hydride by creating a compressed material by accumulating and compressing multiple thin pieces of magnesium, each with a thickness of 150 μm or less, and then reacting the components in the compressed material with hydrogen gas in a hydrogen gas atmosphere. It is said that compressing the Mg-based thin pieces generates strain within the pieces, making it easier for Mg to react with hydrogen gas, thereby improving the yield of magnesium-based hydride.

[0009] Furthermore, Patent Document 2 proposes a magnesium hydride production method in which a unit containing a magnesium compressed body, formed by compressing thin magnesium flakes, is placed in a first chamber connected to the first end of a cylindrical production furnace; the magnesium contained in the unit is heated in the first chamber; the unit containing the heated magnesium compressed body is transported from the first end to the second end of the production furnace while a magnesium hydride structure is produced; and the unit containing the produced magnesium hydride structure is cooled in a second chamber connected to the second end of the production furnace. It is said that the magnesium hydride production apparatus can be operated stably for a long time and variations in the quality of the magnesium hydride structure can be prevented. [Prior art documents] [Patent Documents]

[0010] [Patent Document 1] Patent No. 4425990 [Patent Document 2] Patent No. 6948641 [Disclosure of the Invention] [Problems that the invention aims to solve]

[0011] The purpose of this invention is to propose a magnesium-based hydride manufacturing method that can efficiently produce one MgH2 (magnesium hydride) structure from one Mg compressed body made of magnesium-based raw materials. [Means for solving the problem]

[0012] The present invention, which solves the aforementioned problems, involves a process for producing a magnesium-based hydride, in which a raw material mainly composed of magnesium is combined with hydrogen by reacting the components in a compressed Mg body with hydrogen gas in a hydrogen gas atmosphere within a predetermined pressure range and temperature range, and carrying out this process by housing the compressed Mg body in a sealed reaction box equipped with the function of maintaining the internal space pressure and internal space temperature within the predetermined pressure range and temperature range.

[0013] Furthermore, multiple reaction boxes, each carrying out a process for producing magnesium hydride, are brought into a reaction station, and in each of the brought-in reaction boxes, the process for producing magnesium hydride is carried out while maintaining the internal space pressure and internal space temperature within the predetermined pressure and temperature ranges.

[0014] Furthermore, the reaction box in which the magnesium hydride production process is completed is removed from the reaction station, and a new reaction box containing the compressed Mg, which will start the magnesium hydride production process, is brought into the empty space of the reaction station from which the reaction box was removed, and the magnesium hydride production process is carried out within this new reaction box.

[0015] Such an invention can be illustrated as follows: [1] A first step of producing, by mechanical processing from an ingot containing magnesium as a main component, fibrous magnesium fibers having a diameter of 10 nm to 1,000 nm and a length of at least 0.3 m or more in an inert gas atmosphere, A second step of accumulating the fibrous magnesium fibers produced in the first step in a mold, compressing the fibers by cold isostatic pressing (CIP: Cold Isostatic Pressing), and producing a cylindrical magnesium bar having a specific gravity of 0.7 to 0.9, wherein the circumference of the upper end edge and the circumference of the lower end edge are formed into a mirror surface having an R shape, in an inert gas atmosphere, A third step of sawing the magnesium bar produced in the second step to produce a disk-shaped first magnesium disk in an inert gas atmosphere, A fourth step of pressing the first magnesium disk produced in the third step to produce a thin disk-shaped second magnesium disk having a specific gravity of 1.4 or more in an inert gas atmosphere, a fifth step of producing magnesium-based hydride obtained by combining a raw material containing magnesium as a main component with hydrogen by reacting a component in the second magnesium disk with hydrogen gas in a predetermined pressure range and a predetermined temperature range in a hydrogen gas atmosphere, and A method for producing magnesium-based hydride, comprising:

[0016] [2] the fifth step is performed in a reaction box that hermetically contains the second magnesium disk, the reaction box comprises: opening / closing means that seals the internal space of the reaction box and opens and closes the internal space when the second magnesium disk is loaded into and unloaded from the internal space; a temperature sensor that detects an internal temperature of the sealed internal space; temperature adjustment means that adjusts the temperature of the sealed internal space and comprises a heating and cooling mechanism; a pressure sensor that detects an internal pressure of the sealed internal space; An air supply valve mechanism used when gas is supplied from the outside to the sealed internal space, an exhaust valve mechanism used when gas is exhausted from the sealed internal space to the outside, comprising: the fifth step comprises: a hydrogen replacement step of discharging inert gas from the internal space of the reaction box, in which the second magnesium disk is hermetically accommodated, to the outside through the exhaust valve mechanism, and supplying hydrogen into the internal space through the air supply valve mechanism, so as to replace the sealed internal space with a hydrogen atmosphere; a first temperature and pressure adjustment step of heating the internal space after the hydrogen replacement step by the temperature adjustment means to bring the internal space into the predetermined temperature range state in the fifth step, and supplying hydrogen into the internal space through the air supply valve mechanism to bring the internal space into the predetermined pressure range state in the fifth step, the method for producing a magnesium-based hydride according to [1], comprising the above steps.

[0017] [3] the fifth step comprises: carrying the reaction box after completion of the first temperature and pressure adjustment step into a reaction station, after the reaction box is carried into the reaction station, a second temperature and pressure adjustment step of constantly detecting the internal temperature and internal pressure in the reaction box by the temperature sensor and the pressure sensor, maintaining the internal temperature in the predetermined temperature range state by the temperature adjustment means, and maintaining the internal space in the predetermined pressure range state in the fifth step by supplying hydrogen into the internal space through the air supply valve mechanism, the method for producing a magnesium-based hydride according to [2], comprising the above step.

[0018] [4] a plurality of said reaction boxes can be carried into said reaction station, in the fifth step, the reaction boxes after the first temperature and pressure adjustment step is completed are sequentially fed into the reaction station, A method for producing magnesium hydride, wherein the second temperature and pressure adjustment step is performed in each of the multiple reaction boxes introduced into the reaction station [3].

[0019] [5] The fifth step is carried out in a reaction box that is sealed and housed the second magnesium disk. The reaction box is The reaction box has an opening / closing mechanism for sealing the internal space and opening and closing the internal space when the second magnesium disk is to be placed in and removed from the internal space, A temperature sensor for detecting the internal temperature of the sealed internal space, A temperature control means comprising a heating and cooling mechanism for adjusting the temperature of the sealed internal space, A pressure sensor for detecting the internal pressure of the sealed internal space, An air supply valve mechanism used when gas is supplied from the outside to the sealed internal space, An exhaust valve mechanism used when gas is exhausted from the sealed internal space to the outside, It is equipped with, The fifth step is, The reaction box containing the second magnesium disk is sequentially transported to a reaction station capable of accommodating multiple reaction boxes. In each of the multiple reaction boxes brought into the reaction station, the hydrogen replacement process, the first temperature and pressure control process, and the second temperature and pressure control process are sequentially started. [1] A method for producing magnesium hydride.

[0020] [6] The fifth step is carried out in a reaction box that is sealed and housed the second magnesium disk. The reaction box is The reaction box has an opening / closing mechanism for sealing the internal space and opening and closing the internal space when the second magnesium disk is to be placed in and removed from the internal space, A temperature sensor for detecting the internal temperature of the sealed internal space, A temperature control means comprising a heating and cooling mechanism for adjusting the temperature of the sealed internal space, A pressure sensor for detecting the internal pressure of the sealed internal space, An air supply valve mechanism used when gas is supplied from the outside to the sealed internal space, An exhaust valve mechanism used when gas is exhausted from the sealed internal space to the outside, It is equipped with, In the fifth step, after loading the reaction box containing the second magnesium disk into a reaction station capable of accommodating multiple reaction boxes, In each of the multiple reaction boxes, the hydrogen replacement step, the first temperature and pressure adjustment step, and the second temperature and pressure adjustment step are started in sequence. [1] A method for producing magnesium hydride.

[0021] [7] The fifth step is to remove the reaction box from the reaction station, A third temperature and pressure adjustment step involves detecting the internal temperature and internal pressure inside the reaction box after the extraction step using the temperature sensor and the pressure sensor, lowering the internal temperature to the ambient temperature around the reaction box using the temperature adjustment means, and exhausting the hydrogen to the outside via the exhaust valve mechanism, thereby reducing the internal space to the ambient pressure around the reaction box. An inert gas replacement step is performed by exhausting hydrogen from the internal space to the outside via the exhaust valve mechanism and supplying an inert gas into the internal space via the air supply valve mechanism, thereby replacing the sealed internal space with an inert gas atmosphere. An air replacement step is performed in which the sealed internal space is replaced with air by exhausting the inert gas to the outside from the internal space after the inert gas replacement step via the exhaust valve mechanism and supplying air into the internal space via the air supply valve mechanism, After the atmospheric replacement step, the reaction box is opened by the opening / closing means, and the magnesium hydride is removed from the reaction box to the outside in a removal step. A method for producing a magnesium hydride, further comprising one of the following: [4], [5], [6].

[0022] [8] A method for producing a magnesium-based hydride, further comprising a first inert gas recycling step for recovering and recycling the inert gas exhausted to the outside in the hydrogen replacement step [2].

[0023] [9] A method for producing a magnesium hydride, further comprising a second inert gas recycling step for recovering and recycling the inert gas exhausted to the outside in the atmospheric replacement step [7]. [Effects of the Invention]

[0024] According to this invention, one MgH2 (magnesium hydride) structure can be efficiently produced from one Mg compressed body made of raw materials mainly composed of magnesium. [Brief explanation of the drawing]

[0025] [Figure 1] Figures (a) to (e) illustrate an example of a step in a magnesium-based hydride production method according to one embodiment of the present invention, in which a second magnesium disk, which is a compressed Mg body, is produced from a magnesium ingot. [Figure 2]A diagram showing an example of a magnesium bar produced in the second step of a magnesium hydride production method according to one embodiment of the present invention, wherein (a) is a schematic perspective view, and (b) is a partially omitted front view illustrating that the upper and lower surfaces of the magnesium bar are formed in the shape of end plates, and the circumference of the upper and lower edges are formed in the shape of end plates with a radius (R). [Figure 3] A diagram showing an example of a reaction box in which the fifth step of producing a magnesium hydride is carried out in a sealed internal space, in a method for producing a magnesium hydride according to one embodiment of the present invention, where (a) is a schematic perspective view in a closed (sealed) state, and (b) is a front view in a chained (sealed) state. [Figure 4] Figure 3 shows an example of the internal space of the reaction box, where (a) is a partially omitted front view, and (b) is a partially omitted front view showing an example of a state in which a second magnesium disk (Mg compressed body) used in the fifth step (step for producing magnesium hydride) of the magnesium hydride production method according to one embodiment of the present invention is housed in the internal space of the reaction box as shown in Figure 4(a). [Figure 5] A conceptual diagram illustrating the state in which the hydrogen substitution step is underway in a magnesium-based hydride production method according to one embodiment of the invention. [Figure 6] (b) is a conceptual diagram illustrating the state in which the inert gas replacement step is underway in a magnesium hydride production method according to one embodiment of the present invention, in which the fifth step (the step of producing magnesium hydride) has been completed in the internal space of the reaction box and the inside of the box is being transformed into an inert gas atmosphere. (b) is a conceptual diagram illustrating the state in which the air replacement step, which is performed after the inert gas replacement step, is underway. [Figure 7]In the method for producing a magnesium-based hydride according to one embodiment of the present invention, a plurality of reaction boxes in which the fifth step (the step of producing magnesium-based hydride) proceeds in respective inner spaces are placed on a driving conveyor of a reaction station and moved, the reaction box in which the reaction is completed is taken out from the driving conveyor, and a new reaction box hermetically containing a second magnesium disk (Mg compact) to be subjected to the fifth step (the step of producing magnesium-based hydride) is carried into the empty space where the taking-out was performed. It is a conceptual diagram illustrating an example of the state. DETAILED DESCRIPTION OF THE INVENTION

[0026] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. <Step of producing Mg compact> In the method for producing magnesium-based hydride of the present embodiment, an example of the step of producing an Mg compact to be subjected to the magnesium-based hydride production step will be described. For example, the Mg compact can be produced by performing the following first to fourth steps.

[0027] <First Step> Fibrous magnesium fibers having a diameter of 10 nm to 1,000 nm and a length of at least 0.3 m or more are produced from an ingot containing magnesium as a main component by mechanical processing in an inert gas atmosphere.

[0028] For example, an Mg ingot (for example, 8 kg per piece, specific gravity: 1.74), three of which are shown as reference photographs in FIG. 1(a), is cut in an Ar gas atmosphere to produce fibrous magnesium fibers having a diameter of 10 nm to 1,000 nm and a length of at least 0.3 m or more in an Ar gas atmosphere. FIG. 1(b) shows, as a reference photograph, an example of the fibrous magnesium fiber produced in the first step.

[0029] <Second Step> In the first step, the fibrous magnesium fibers produced are accumulated in a mold in an inert gas atmosphere and compressed by cold isostatic pressing (CIP) to produce a cylindrical magnesium bar with a specific gravity of 0.7 to 0.9, where the upper and lower edges have a mirror-like surface with a radius (R). Figure 1(c) is a reference photograph showing a portion of the magnesium bar (cylindrical, 300 mm in diameter and 1,000 mm in length) produced in the second step, with some parts omitted.

[0030] This second step involves compressing the fibrous magnesium fibers accumulated in the mold using a cold isostatic pressing (CIP) method in an inert gas atmosphere (for example, an Ar gas atmosphere).

[0031] Cold isostatic pressing (CIP) is a conventionally known method and is performed using a conventionally known dry cold isostatic pressing apparatus.

[0032] The dry cold isostatic pressurizing device described above generally consists of a vertically cylindrical molding container and an upper and lower lid that close the upper and lower openings of the molding container, respectively, with a cylindrical molding rubber mold arranged around the inside of the molding container via a pressure rubber mold.

[0033] The top lid has a double-layered structure with an upper punch installed within a hollow top lid frame, and similarly, the bottom lid has a double-layered structure with a lower punch installed within a hollow bottom lid frame. The upper punch is fitted by a predetermined amount into the upper opening of the molding rubber mold, and the lower punch is fitted by a predetermined amount into the lower opening of the molding rubber mold, thereby forming a cylindrical molding chamber for the workpiece surrounded by these upper punch, molding rubber mold, molding rubber mold, and lower punch.

[0034] The cold isostatic pressing (CIP) method involves pressurizing the workpiece through a rubber mold pre-installed in a pressure vessel. This method allows for smooth filling, pressurizing, and removal of the molded product, making it easy to automate and suitable for mass production.

[0035] The magnesium bar 30 (Figure 2(a)) with a specific gravity of 0.7 to 0.9, which is produced by compression processing using the cold isostatic pressing method (CIP) performed in an inert gas atmosphere (for example, in an Ar gas atmosphere) using the dry cold isostatic pressing apparatus described above, is cylindrical in shape, and the circumference of the upper edge 31 and the circumference of the lower edge 32 are formed in a mirror-like shape with a radius (R), as illustrated in Figure 2(b).

[0036] In other words, by performing compression processing by the cold isostatic pressing method (CIP) using the dry cold isostatic pressing apparatus described above, as shown in Figure 2(b), the upper surface 30a of the magnesium bar 30 after compression processing is formed in the shape of an end plate, and the circumference of the upper edge 31a is formed in the shape of an end plate with a radius. Similarly, the lower surface 30 of the magnesium bar 30 after compression processing is formed in the shape of an end plate, and the circumference of the lower edge 32a is formed in the shape of an end plate with a radius.

[0037] When a compressed Mg body, used in the process of producing magnesium-based hydrides, is manufactured by a conventional press method involving X-axis, Y-axis, and Z-axis compression, an octahedral Mg body is produced. The eight corners and eight edges of this octahedral Mg body have a high compression ratio. As a result, the hydrogenation rate in these areas becomes high, approaching 100%, leading to the phenomenon described later, where the hydrogenation rate decreases in the process of producing magnesium-based hydrides from the compressed Mg body.

[0038] The compression process performed in this embodiment is carried out by the cold isostatic pressing method (CIP) using the dry cold isostatic pressing apparatus described above. As a result, the magnesium bar 30 (Figure 2(a)) with a specific gravity of 0.7 to 0.9 after compression is cylindrical, as illustrated in Figure 2(b), with the upper surface 30a and lower surface 30b formed in the shape of end plates, and the upper edge circumference 31 and lower edge circumference 32 formed in the shape of end plates with a radius. Therefore, the aforementioned phenomena that occur in conventional press methods that perform compression using X-axis, Y-axis, and Z-axis compression can be suppressed.

[0039] <Third step> The magnesium bar 30 (Figure 2) produced in the second step is sawn in an inert gas atmosphere (for example, an Ar gas atmosphere) to produce a disc-shaped first magnesium disk. This results in the first magnesium disk (diameter 300 mm) shown in the reference photograph in Figure 1(d). For example, a cylindrical magnesium bar 30 (Figure 2(a)) produced in the second step, with a vertical length (length between the upper surface 30a and the lower surface 30b of the cylindrical magnesium bar 30) of 1,000 mm, is sawn to produce first magnesium disks (diameter 300 mm) (Figure 1(d)) with a thickness of 100 mm each.

[0040] As will be described later, the compressed Mg body produced through the first to fourth steps is subjected to the magnesium hydride manufacturing process. In order to achieve a good hydrogenation rate in the short-time magnesium hydride manufacturing process, it is desirable that the compressed Mg body be compressed to a specific gravity of 1.4 or higher.

[0041] However, it is not easy to produce a compressed Mg body with a specific gravity of 1.4 or higher in one step from the fibrous magnesium fibers produced in the first step. Therefore, it is advantageous in terms of efficiency to produce a compressed Mg body by first producing a magnesium bar with a uniform specific gravity of 0.7 to 0.9 by cold isostatic compression in the second step described above, then producing a first magnesium disc with a predetermined thickness by sawing in the third step, and finally producing a compressed Mg body with a specific gravity of 1.4 or higher by compression in the fourth step described later.

[0042] Furthermore, the reason why the specific gravity of the magnesium bar produced by the cold isostatic compression process in the second step described above is set to a range of 0.7 to 0.9 is that a first magnesium disc with a predetermined thickness is produced from the magnesium bar by sawing in the third step, and then a compressed Mg body with a specific gravity of 1.4 or higher is produced by compression in the subsequent second step.

[0043] <Fourth process> The first magnesium disc produced in the third step described above is pressed in an inert gas atmosphere (for example, an Ar gas atmosphere) to produce a second magnesium disc that is thin, disc-shaped, and has a specific gravity of 1.4 or higher. This results in the second magnesium disc (300 mm in diameter, 25 mm thick) shown in the reference photograph in Figure 1(e).

[0044] This second magnesium disk (Figure 1(e)) becomes a compressed Mg body that is subsequently used in the process of producing magnesium hydride.

[0045] This compressed Mg material is an ingot primarily composed of magnesium (specific gravity 1.74 g / cm³) produced in the first step described above. 3 From this, fibrous magnesium fibers with a diameter of 10 nm to 1,000 nm and a length of at least 0.3 m are produced by machining, and these are then assembled in a mold and compressed.

[0046] Therefore, this second magnesium disc with a specific gravity of 1.4 or higher is a porous structure, and the effective surface area of ​​the fibrous magnesium fibers made from magnesium ingots is large. In addition, as mentioned above, the compression process to achieve a specific gravity of 1.4 or higher results in a good hydrogenation rate in a short-time magnesium-based hydride manufacturing process.

[0047] In order to achieve a good hydrogenation rate in such a short-time magnesium-based hydride manufacturing process, it is desirable that the specific gravity of the Mg compressed body produced in the fourth step, i.e., the second magnesium disk, be at least 1.4.

[0048] Furthermore, the compression process in the fourth step can be performed using the cold isostatic pressing method (CIP) with the dry cold isostatic pressing device described above, instead of press working.

[0049] However, by manufacturing a cylindrical magnesium bar in the second step, with its upper and lower surfaces formed in the shape of end plates, and the upper and lower edges having rounded ends, it is desirable that the second step be a cold isostatic pressing (CIP) compression process using a dry cold isostatic pressing device, in order to suppress the occurrence of phenomena that occur in conventional compression processes using presses that perform X-axis, Y-axis, and Z-axis compression as described above.

[0050] On the other hand, considering the equipment costs, it is advantageous to perform the compression process in the fourth step using press working, as mentioned above.

[0051] As described above, in the magnesium hydride production method of the present invention, all steps (steps 1 to 4 in the above example) for producing a compressed Mg body (i.e., the second magnesium disk described above) to be used in the magnesium hydride production process from a magnesium ingot (e.g., 8 kg / 1 piece, specific gravity: 1.74) are carried out in an inert gas atmosphere (e.g., in an Ar gas atmosphere).

[0052] Furthermore, the inert gas (e.g., Ar gas) used to carry out the above-described process in an inert gas atmosphere (e.g., Ar gas atmosphere) can be recovered, recycled, and reused after the completion of the process. Since inert gases (e.g., Ar gas) are scarce and expensive, having such an inert gas recycling process is advantageous in terms of cost.

[0053] <Magnesium-based hydride manufacturing process (fifth step)> In the magnesium-based hydride production method of this embodiment, after producing a compressed Mg body, i.e., a second magnesium disk, as described above, the components within the second magnesium disk (compressed Mg body) are reacted with hydrogen gas in a hydrogen gas atmosphere under a predetermined pressure range and a predetermined temperature range to produce a magnesium-based hydride, which is formed by the combination of a raw material mainly composed of magnesium and hydrogen.

[0054] The predetermined pressure range in the hydrogen gas atmosphere described above is, as conventionally known, for example, 6,000 hPa to 10,000 hPa, and the predetermined temperature range in the hydrogen gas atmosphere is, as conventionally known, for example, 550°C to 590°C. In this embodiment, various forms described below can be adopted as the fifth step (magnesium-based hydride production step).

[0055] <Reaction box used in the fifth step (magnesium hydride production step)> In this embodiment, the fifth step (magnesium hydride production step) is carried out in a reaction box that contains the second magnesium disk (Mg compressed body) produced in the first to fourth steps described above.

[0056] Here, one embodiment of this reaction box will be described with reference to Figures 3 and 4.

[0057] The reaction box 1, shown as an example in Figures 3 and 4, is made of austenitic stainless steel and has a rectangular parallelepiped shape consisting of a front wall 5, a back wall 6, a top wall 2, a bottom wall 7, a left side wall 3, and a right side wall 4. The internal space 12 of the reaction box 1 is formed by being enclosed by these walls.

[0058] The reaction box 1 is equipped with an opening / closing mechanism (not shown), which opens or closes the front wall 5, thereby opening or closing the internal space 12.

[0059] In the illustrated embodiment, the opening and closing mechanism (not shown) seals the internal space 12 of the reaction box 1 by closing the front wall 5 (Figure 3), and allows the second magnesium discs produced in the first to fourth steps described above to be stored in and removed from the internal space 12 by opening the front wall 5 (Figure 4).

[0060] In the illustrated embodiment, an upper support shelf 13 is formed in the internal space 12 of the reaction box 1 by a plurality of support rods 13a, 13b, ..., 13i that extend from the back side to the front side of the drawing at predetermined intervals in the left-right direction as shown in Figure 4(a), and a lower support shelf 14 is formed by a plurality of support rods 14a, 14b, ..., 14i that extend from the back side to the front side of the drawing at predetermined intervals in the left-right direction as shown in Figure 4(a).

[0061] As shown in Figure 4, with the front wall 5 open and the internal space 12 open by an opening / closing mechanism (not shown), the second magnesium discs (Mg compressed bodies) 20a and 20b produced in the first to fourth steps described above are placed on the support shelves 13 and 14. Then, with the front wall 5 closed and the internal space 12 closed by an opening / closing mechanism (not shown) (Figure 3), the magnesium hydride production process (fifth step) is carried out on the second magnesium discs (Mg compressed bodies) 20a and 20b. In this way, the process of sealing and housing the Mg compressed bodies (i.e., the second magnesium discs described above) to be used in the magnesium hydride production process within the internal space 12 of the reaction box 1 can also be carried out in an inert gas atmosphere (for example, in an Ar gas atmosphere).

[0062] In the diagram, two second magnesium disks (Mg compressed bodies) used in the magnesium hydride production process (fifth step) are housed within the internal space 12 of the reaction box 1. However, this can be modified to accommodate only one disk, or three or more disks.

[0063] Furthermore, the configuration in which the second magnesium disk (Mg compressed body) used in the magnesium hydride production process (fifth step) is arranged within the internal space 12 of the reaction box 1 can also be varied.

[0064] The reaction box 1 includes a temperature sensor, a temperature adjustment means, a pressure sensor, an air supply valve mechanism, and an exhaust valve mechanism.

[0065] In the illustrated embodiment, a temperature control mechanism 8 that serves as both a temperature sensor and a temperature control means, a pressure sensor 9, an air supply valve mechanism 10, and an exhaust valve mechanism 11 are provided in the reaction box 1.

[0066] The temperature control mechanism 8 comprises an outer temperature control mechanism part 8a located outside the reaction box 1 and an inner temperature control mechanism part 8b located inside the reaction box 1. It serves as a temperature sensor to detect the internal temperature of the sealed internal space 12 and as a temperature control means consisting of a heating and cooling mechanism to adjust the temperature of the sealed internal space 12.

[0067] The pressure sensor 9 comprises an outer pressure sensor portion 9a located outside the reaction box 1 and an inner pressure sensor portion 9b located inside the reaction box 1, and plays a role in detecting the internal pressure of the sealed internal space 12.

[0068] The air supply valve mechanism 10 comprises an outer air supply valve mechanism 10a located outside the reaction box 1 and an inner air supply valve mechanism 10b located inside the reaction box 1, and is used when gas is supplied from the outside to the sealed internal space 12.

[0069] The exhaust valve mechanism 11 comprises an outer exhaust valve mechanism portion 11a located outside the reaction box 1 and an inner exhaust valve mechanism portion 11b located inside the reaction box 1, and is used when gas is exhausted to the outside from the sealed internal space 12.

[0070] Although not shown in Figures 3 and 4, the air supply valve mechanism 10 is connected to an air supply pipe that supplies a predetermined gas from outside the reaction box 1, and the exhaust valve mechanism 11 is connected to an exhaust pipe that exhausts gas from inside the reaction box 1 to the outside.

[0071] Furthermore, although not shown in Figures 3 and 4, the temperature control mechanism 8, pressure sensor 9, air supply valve mechanism 10, and exhaust valve mechanism 11 each communicate with an external control device (not shown) via predetermined wiring to monitor temperature and pressure. This controls the temperature adjustment of the sealed internal space 12 by heating or cooling via the temperature control mechanism 8, the supply of gas to the internal space 12 of the reaction box 1 via the air supply valve mechanism 10, the exhaust of gas from the internal space 12 of the reaction box 1 to the outside via the exhaust valve mechanism 11, and the adjustment of the internal pressure by supplying gas to the internal space 12 of the reaction box 1 via the air supply valve mechanism 10.

[0072] Below, we will describe several embodiments in which the second magnesium disk (Mg compressed body) produced in the first to fourth steps described above is sealed and housed in the reaction box 1 described above, as illustrated in Figures 3 and 4, and the fifth step (magnesium hydride production step) is carried out.

[0073] <First form of the fifth process (magnesium hydride production process)> As described above, in a reaction box 1 in an inert gas atmosphere (for example, an Ar gas atmosphere), the fifth step (magnesium hydride production step) proceeds as follows in the reaction box 1 in which the compressed Mg body to be used in the magnesium hydride production step (i.e., the second magnesium disk described above) is sealed and housed in the internal space 12 of the reaction box 1.

[0074] (Hydrogen replacement process) The inert gas (argon gas as described above) is exhausted from the internal space 12 of the reaction box 1 to the outside via the exhaust valve mechanism 11, and hydrogen is supplied into the internal space 12 via the air supply valve mechanism 10, thereby replacing the sealed internal space 12 with a hydrogen atmosphere (Figure 5).

[0075] The process of sealing and housing the compressed Mg body (the second magnesium disk described above) to be used in the magnesium hydride production process within the internal space 12 of the reaction box 1 is carried out in an inert gas atmosphere (for example, an Ar gas atmosphere). This process exhausts the inert gas (for example, Ar gas) present in the internal space 12 to the outside, and simultaneously replaces the sealed internal space 12 of the reaction box 1 with a hydrogen atmosphere by supplying hydrogen gas into the internal space 12.

[0076] Furthermore, the system can be configured to include a first inert gas recycling process in which the inert gas (argon gas, as mentioned above) exhausted to the outside during the hydrogen replacement process is recovered and recycled.

[0077] The inert gas recycled in the first inert gas recycling process (for example, the argon gas mentioned above) can be used as the inert gas (Ar gas) when performing processes such as the production of a compressed Mg body (the second magnesium disk mentioned above) for use in the magnesium hydride production process from a magnesium-based ingot (for example, 8 kg / 1 piece, specific gravity: 1.74) (steps 1 to 4 in the example above), or the sealing and housing of the compressed Mg body (the second magnesium disk mentioned above) for use in the magnesium hydride production process within the internal space 12 of the reaction box 1, all in an inert gas atmosphere (for example, an Ar gas atmosphere). It can also be used to supply the gas into the internal space 12 of the reaction box 1 in the inert gas replacement process described later.

[0078] Since argon gas is scarce and expensive, a magnesium-based hydride production method that incorporates a primary inert gas recycling process offers cost advantages.

[0079] (First temperature and pressure control process) After the hydrogen replacement process, the internal space 12 is heated by a temperature control means (temperature control mechanism 8) to bring it to a predetermined temperature range (550°C to 590°C) in a hydrogen gas atmosphere required for the magnesium-based hydride production process. At the same time, hydrogen is supplied into the internal space 12 via the air supply valve mechanism 10 to bring it to a predetermined pressure range (6,000 hPa to 10,000 hPa) in a hydrogen gas atmosphere required for the magnesium-based hydride production process.

[0080] This first temperature and pressure adjustment process initiates a process in which the components in the second magnesium discs (Mg compressed bodies) 20a and 20b react with hydrogen gas to produce a magnesium-based hydride, which is a compound of magnesium-based raw materials and hydrogen.

[0081] <Second form of the fifth process (magnesium hydride production process)> After the start of the "first temperature and pressure adjustment process" in the first configuration described above, the temperature and pressure of the internal space 12 of the reaction box 1 fluctuate as the magnesium hydride production process progresses. Therefore, the reaction box 1 after the start of the "first temperature and pressure adjustment process" in the first configuration described above is moved to a predetermined reaction station, and the temperature and pressure of the internal space 12 of the reaction box 1 are maintained within the predetermined temperature range (550°C to 590°C) and predetermined pressure range (6,000 hPa to 10,000 hPa) required for the magnesium hydride production process in a hydrogen gas atmosphere.

[0082] In other words, the reaction box 1, after the "first temperature and pressure adjustment process" in the first form described above has been completed, is transported to the reaction station.

[0083] After the reaction box has been brought into the reaction station, the second temperature and pressure control process, as described below, is carried out.

[0084] In this second temperature and pressure control step, the internal temperature and pressure inside the reaction box 1 are constantly detected by a temperature sensor (temperature control mechanism 8) and a pressure sensor 9. The temperature control means (temperature control mechanism 8) maintains the internal temperature within a predetermined temperature range (550°C to 590°C), and hydrogen is supplied into the internal space 12 via the air supply valve mechanism 10 to maintain the internal space 12 within a predetermined pressure range (6,000 hPa to 10,000 hPa).

[0085] When the reaction box 1, after the "first temperature and pressure adjustment process" in the first embodiment described above has been completed, is brought into the reaction station and the second temperature and pressure adjustment process is carried out as described above, multiple reaction boxes 1 can be brought into the reaction station, and the reaction boxes 1, after the first temperature and pressure adjustment process described above has been completed, can be sequentially put into the reaction station, and the second temperature and pressure adjustment process can be carried out in each of the multiple reaction boxes 1 that have been put into the reaction station.

[0086] Figure 7 illustrates an example of such an embodiment.

[0087] The reaction station 100 is equipped with a drive conveyor 101 that carries and transports multiple reaction boxes.

[0088] After the "first temperature and pressure adjustment process" described above in the first form is completed, the reaction box 1a is transported to the drive conveyor 101 of the reaction station 100, as indicated by arrow 103.

[0089] Reaction box 1b in Figure 7 is the reaction box after the completion of the "first temperature and pressure adjustment process" described above in the first embodiment, prior to reaction box 1a. As it moves in the direction indicated by arrow 102 in Figure 7, the second temperature and pressure adjustment process described above is underway.

[0090] In this way, multiple reaction boxes 1 can be brought into the reaction station, and after the first temperature and pressure adjustment process described above is completed, the reaction boxes 1h, 1g, 1f, 1e, 1d, 1c, 1b, and 1a are sequentially fed into the drive conveyor 101 of the reaction station 100, and the second temperature and pressure adjustment process described above is performed in each of the multiple reaction boxes 1h, 1g, 1f, 1e, 1d, 1c, 1b, and 1a that have been fed into the station.

[0091] <Third form of the fifth process (magnesium hydride manufacturing process)> In this third embodiment, as described above, the fifth step (magnesium-based hydride production step) is carried out in the reaction box 1 described above, but the specific embodiment differs from the second embodiment described above and is as follows.

[0092] Specifically, multiple reaction boxes 1, each containing a sealed second magnesium disc 20a or 20b, are sequentially loaded onto a drive conveyor 101 of a reaction station 100 capable of receiving multiple reaction boxes 1. In each of the reaction boxes 1h, 1g, 1f, 1e, 1d, 1c, 1b, and 1a loaded into the reaction station 100, the hydrogen replacement process, the first temperature and pressure adjustment process, and the second temperature and pressure adjustment process are sequentially initiated.

[0093] <Process for removing magnesium hydride> As described above, once the fifth step (magnesium hydride production step) is completed in the internal space 12 of the reaction box 1, the magnesium hydride can be removed from the reaction box 1 in the following manner.

[0094] (Removal process) The reaction box 1h, in which the fifth step (magnesium hydride production step) described above has been completed, is removed from the drive conveyor 101 of the reaction station 100 as indicated by arrow 104 (Figure 7).

[0095] (Third temperature and pressure control process) The internal temperature and pressure inside the reaction box 1h after the extraction process are detected by a temperature sensor (temperature control mechanism 8) and a pressure sensor 9. The temperature control means (temperature control mechanism 8) reduces the internal temperature to the ambient temperature surrounding the reaction box 1h, and the internal space 12 is depressurized to the ambient pressure surrounding the reaction box 1h by exhausting hydrogen to the outside via the exhaust valve mechanism 11.

[0096] (Inert gas replacement process) The sealed internal space 12 is replaced with an inert gas atmosphere by exhausting hydrogen from the internal space 12 to the outside via the exhaust valve mechanism 11 and supplying an inert gas (for example, argon gas) into the internal space 12 via the air supply valve mechanism 10 (Figure 6(a)).

[0097] (Atmospheric displacement process) After the inert gas replacement process described above, the inert gas (argon gas) is exhausted to the outside from the internal space 12 via the exhaust valve mechanism 11, and at the same time, air is supplied into the internal space 12 via the air supply valve mechanism 10, thereby replacing the sealed internal space 12 with air (Figure 6(b)).

[0098] Furthermore, the system can be configured to include a second inert gas recycling process in which the inert gas (argon gas, as mentioned above) exhausted to the outside during the atmospheric replacement process is recovered and recycled.

[0099] The inert gas recycled in the second inert gas recycling process (for example, the argon gas mentioned above) can be used as the inert gas (Ar gas) when performing processes such as the production of a compressed Mg body (the second magnesium disk mentioned above) for use in the magnesium hydride production process from the magnesium-based ingot (for example, 8 kg / 1 piece, specific gravity: 1.74) (steps one to four in the example above), or the sealing and housing of the compressed Mg body (the second magnesium disk mentioned above) for use in the magnesium hydride production process within the internal space 12 of the reaction box 1, all in an inert gas atmosphere (for example, an Ar gas atmosphere). It can also be used to supply the inert gas into the internal space 12 of the reaction box 1 during this inert gas replacement process.

[0100] Since argon gas is scarce and expensive, a magnesium-based hydride production method that includes a second inert gas recycling process offers cost advantages.

[0101] (Export process) After the atmospheric replacement process described above, the reaction box 1h is opened by an opening / closing mechanism (not shown), and the magnesium hydride is removed from the reaction box 1h to the outside.

[0102] In this way, one MgH2 (magnesium hydride) structure can be efficiently produced from one Mg compressed body made from raw materials mainly composed of magnesium.

[0103] Although embodiments of the present invention have been described above with reference to the attached drawings, the present invention is not limited to the embodiments described above, and can be modified in various ways within the technical scope as understood from the claims.

[0104] For example, the above description describes an embodiment in which a reaction station containing multiple reaction boxes 1, each carrying out the fifth process (magnesium hydride production process) within its internal space 12, is equipped with a drive conveyor 101. The fifth process (magnesium hydride production process) proceeds within the internal space 12 of each reaction box 1 as it is sequentially transported onto the drive conveyor 101. The fifth process (magnesium hydride production process) is completed while the reaction boxes 1 are being transported on the drive conveyor 101, and the completed reaction boxes 1 are removed from the reaction station (drive conveyor 101). A new reaction box 1 is then transported into the empty space left by the removal of the previous reaction box 1.

[0105] Alternatively, a fixed (pit-type) reaction station can be used. This fixed (pit-type) reaction station has a space that accommodates multiple reaction boxes 1, each carrying out the fifth step (magnesium-based hydride production step) within its internal space 12.

[0106] In this case as well, reaction boxes 1 are sequentially brought into the space of the fixed (pit-type) reaction station, and the fifth step (magnesium-based hydride production step) is carried out in the internal space 12 of each reaction box 1. Reaction boxes 1 that have completed their reaction are sequentially removed from the space of the fixed (pit-type) reaction station according to the order in which they were brought in, and a new reaction box 1 is brought into the empty space left by the removal of the reaction box 1.

Claims

1. The first step involves producing fibrous magnesium fibers with a diameter of 10 nm to 1,000 nm and a length of at least 0.3 m from a magnesium-based ingot by machining in an inert gas atmosphere. In the second step, the fibrous magnesium fibers produced in the first step are accumulated in a mold and compressed by cold isostatic pressing (CIP) to produce a cylindrical magnesium bar with a specific gravity of 0.7 to 0.9, which has a mirror-like surface with rounded upper and lower edges, in an inert gas atmosphere. In the third step, the magnesium bar produced in the second step is cut with a saw to create a disc-shaped first magnesium disc in an inert gas atmosphere. In the fourth step, the first magnesium disc produced in the third step is pressed to form a second magnesium disc, which is a thin, disc-shaped disc with a specific gravity of 1.4 or higher, in an inert gas atmosphere. A fifth step involves reacting the components in the second magnesium disk with hydrogen gas in a hydrogen gas atmosphere under predetermined pressure and temperature ranges to produce a magnesium-based hydride, in which a magnesium-based raw material is combined with hydrogen. A method for producing a magnesium-based hydride that possesses the following properties.

2. The fifth step is carried out in a reaction box that is sealed and housed the second magnesium disk. The reaction box is The reaction box has an opening / closing mechanism for sealing the internal space and for opening and closing the internal space when the second magnesium disk is to be placed in and removed from the internal space, A temperature sensor for detecting the internal temperature of the sealed internal space, A temperature control means comprising a heating and cooling mechanism for adjusting the temperature of the sealed internal space, A pressure sensor for detecting the internal pressure of the sealed internal space, An air supply valve mechanism used when gas is supplied from the outside to the sealed internal space, An exhaust valve mechanism used when gas is exhausted from the sealed internal space to the outside, It is equipped with, The fifth step is, A hydrogen replacement step is performed by exhausting inert gas to the outside from the internal space of the reaction box in which the second magnesium disc is sealed and housed, via the exhaust valve mechanism, and supplying hydrogen into the internal space via the air supply valve mechanism, thereby replacing the sealed internal space with a hydrogen atmosphere. A first temperature and pressure adjustment step involves heating the internal space after the hydrogen replacement step using the temperature adjustment means to bring it to the predetermined temperature range state in the fifth step, and supplying hydrogen to the internal space via the air supply valve mechanism to bring the internal space to the predetermined pressure range state in the fifth step. A method for producing magnesium hydride according to claim 1, comprising:

3. The fifth step is, After the first temperature and pressure adjustment process is completed, the reaction box is transported to the reaction station. After the reaction box is brought into the reaction station, The second temperature and pressure control step involves continuously detecting the internal temperature and pressure within the reaction box using the temperature sensor and pressure sensor, maintaining the internal temperature within the predetermined temperature range using the temperature control means, and maintaining the internal space within the predetermined pressure range in the fifth step by supplying hydrogen to the internal space via the air supply valve mechanism. A method for producing magnesium hydride according to claim 2, comprising:

4. The reaction station is capable of receiving multiple reaction boxes. In the fifth step, the reaction boxes, after the first temperature and pressure adjustment step has been completed, are sequentially placed into the reaction station. The method for producing a magnesium hydride according to claim 3, wherein the second temperature and pressure adjustment step is performed in each of the plurality of reaction boxes introduced into the reaction station.

5. The fifth step is carried out in a reaction box that is sealed and housed the second magnesium disk. The reaction box is The reaction box has an opening / closing mechanism for sealing the internal space and for opening and closing the internal space when the second magnesium disk is to be placed in and removed from the internal space, A temperature sensor for detecting the internal temperature of the sealed internal space, A temperature control means comprising a heating and cooling mechanism for adjusting the temperature of the sealed internal space, A pressure sensor for detecting the internal pressure of the sealed internal space, An air supply valve mechanism used when gas is supplied from the outside to the sealed internal space, An exhaust valve mechanism used when gas is exhausted from the sealed internal space to the outside, It is equipped with, The fifth step is, The reaction box containing the second magnesium disk is sequentially transported to a reaction station capable of accommodating multiple reaction boxes. In each of the multiple reaction boxes brought into the reaction station, the hydrogen replacement process, the first temperature and pressure control process, and the second temperature and pressure control process are sequentially started. A method for producing a magnesium-based hydride according to claim 1.

6. The fifth step is carried out in a reaction box that is sealed and housed the second magnesium disk. The reaction box is The reaction box has an opening / closing mechanism for sealing the internal space and for opening and closing the internal space when the second magnesium disk is to be placed in and removed from the internal space, A temperature sensor for detecting the internal temperature of the sealed internal space, A temperature control means comprising a heating and cooling mechanism for adjusting the temperature of the sealed internal space, A pressure sensor for detecting the internal pressure of the sealed internal space, An air supply valve mechanism used when gas is supplied from the outside to the sealed internal space, An exhaust valve mechanism used when gas is exhausted from the sealed internal space to the outside, It is equipped with, In the fifth step, after loading the reaction box containing the second magnesium disk into a reaction station capable of receiving multiple reaction boxes, In each of the multiple reaction boxes, the hydrogen replacement step, the first temperature and pressure adjustment step, and the second temperature and pressure adjustment step are started in sequence. A method for producing a magnesium-based hydride according to claim 1.

7. The fifth step is to remove the reaction box from the reaction station, A third temperature and pressure adjustment step involves detecting the internal temperature and internal pressure inside the reaction box after the extraction step using the temperature sensor and the pressure sensor, lowering the internal temperature to the ambient temperature around the reaction box using the temperature adjustment means, and exhausting the hydrogen to the outside via the exhaust valve mechanism, thereby reducing the internal space to the ambient pressure around the reaction box. An inert gas replacement step is performed by exhausting hydrogen from the internal space to the outside via the exhaust valve mechanism and supplying an inert gas into the internal space via the air supply valve mechanism, thereby replacing the sealed internal space with an inert gas atmosphere. An atmospheric replacement step is performed in which the sealed internal space is replaced with air by exhausting the inert gas to the outside from the internal space after the inert gas replacement step via the exhaust valve mechanism and supplying air into the internal space via the air supply valve mechanism, After the atmospheric replacement step, the reaction box is opened by the opening / closing means, and the magnesium hydride is removed from the reaction box to the outside in a removal step. A method for producing a magnesium-based hydride according to any one of claims 4, 5, or 6, further comprising the above.

8. The method for producing a magnesium-based hydride according to claim 2, further comprising a first inert gas recycling step of recovering and recycling the inert gas exhausted to the outside in the hydrogen replacement step.

9. The method for producing a magnesium-based hydride according to claim 7, further comprising a second inert gas recycling step for recovering and recycling the inert gas exhausted to the outside in the aforementioned atmospheric replacement step.

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