JP2013023406A - Manufacturing method for magnesium hydride and manufacturing unit for magnesium hydride - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing high purity magnesium hydride (MgH) using magnesium (Mg) containing impurity metal or alloy material.SOLUTION: The method includes a vaporization process in which a raw material mainly containing magnesium and also containing impurity metal having a vapor pressure higher than magnesium is heated and evaporated in an atmosphere of hydrogen gas, and a condensation process in which magnesium hydride is condensed by contacting the evaporated raw material gas with a condensation section which has a lower temperature than the heating temperature of the raw material. In the condensation process, at least a part of the condensation section is controlled at a lower temperature than the heating temperature of the raw material and higher temperature than the melting temperature of the impurity metal.

Description

  The present invention relates to a magnesium hydride manufacturing method and a magnesium hydride manufacturing apparatus using a hydrochemical vapor deposition (HCVD) method.

Hydrogen, which is an important energy carrier for realizing a petroleum-free and low-carbon clean society, can be produced by biomass or water electrolysis. And it can be converted into electricity with high efficiency by the fuel cell. However, since hydrogen has a low volumetric energy density, it must be compressed and liquefied, stored in a hydrogen storage metal material, or converted into a compound such as methane, ammonia, or organic hydride. In terms of safe handling, storage in a hydrogen storage metal material such as magnesium hydride MgH ₂ is the best.

  Patent Document 1 discloses a method for producing a magnesium hydride from pure magnesium Mg using a thermal equilibrium method.

  Patent Document 2 discloses a hydrogenation chemical vapor deposition method in which pure magnesium is evaporated in a hydrogen atmosphere and magnesium hydride is deposited in a low temperature portion. Magnesium hydride obtained by the HCVD method has a purity of 98% or more, and has a fiber shape with a diameter of several hundred nm and a length of several tens of μm. Practical favorable properties that show good hydrogen storage / release characteristics without the activation treatment required for normal metal hydrides, and that it does not collapse even after repeated storage / release due to its unique form. It also has.

  On the other hand, Patent Documents 3 and 4 disclose a method for producing pure magnesium from a magnesium alloy scrap material by a vacuum distillation purification method.

Patent No. 4083786 JP 2006-76803 A Japanese Patent Laid-Open No. 10-158753 JP 2002-348621 A

  However, the methods disclosed in Patent Documents 1 and 2 are based on the premise that pure magnesium is used as a raw material, and using magnesium containing an impurity metal, for example, low-grade magnesium or alloy material such as magnesium alloy scrap material, There was a problem that high-purity magnesium hydride could not be produced.

  The present invention has been made in view of such circumstances, and a magnesium hydride capable of producing high-purity magnesium hydride by a hydrochemical vapor deposition method using magnesium or an alloy material containing an impurity metal as a raw material. It aims at providing a manufacturing method and a magnesium hydride manufacturing apparatus.

  A magnesium hydride production method according to the present invention includes an evaporation step of evaporating a raw material containing magnesium as a main component, containing an impurity metal having a higher vapor pressure than magnesium, by heating in a hydrogen gas atmosphere, A condensing step of condensing magnesium hydride by bringing the evaporated raw material gas into contact with a condensing portion having a temperature lower than the heating temperature, wherein the condensing step includes at least part of the condensing portion at a heating temperature of the raw material. The temperature is adjusted to a temperature lower than that of the impurity metal and higher than the melting point of the impurity metal.

  In the magnesium hydride manufacturing method according to the present invention, before the evaporation step, the source material is heated in an inert gas atmosphere to evaporate the impurity metal contained in the source material, and the impurity metal evaporated And a step of removing steam.

  The magnesium hydride manufacturing method according to the present invention is characterized in that the raw material contains zinc and the condensing step heats the condensing part to 400 to 500 ° C.

  The method for producing magnesium hydride according to the present invention includes a step of washing the raw material using an acid before heating the raw material.

  In the magnesium hydride manufacturing method according to the present invention, in the evaporation step, the first space where the raw material is heated in a hydrogen gas atmosphere is separated from the second space where the magnesium hydride is condensed. The raw material is evaporated, and the condensation step condenses the magnesium hydride in a state where the first space and the second space are communicated and the pressure of the second space is lower than the pressure of the first space. It is characterized by making it.

  A magnesium hydride production apparatus according to the present invention includes an enclosure containing an impurity metal having a higher vapor pressure than magnesium and enclosing a magnesium-based material in a hydrogen gas atmosphere, and hydrogen gas in the enclosure. At least one of a hydrogen gas supply unit to be supplied, a heating unit for evaporating the raw material by heating in a hydrogen gas atmosphere, a condensing unit for condensing magnesium hydride in contact with the evaporated source gas, and And a temperature control unit that adjusts the temperature to a temperature lower than the heating temperature of the raw material and higher than the melting point of the impurity metal.

  The magnesium hydride manufacturing apparatus according to the present invention includes a gate valve that separates the first space on the heating unit side and the second space on the condensing unit side, and a vacuum connected to the second space side of the enclosure. And a pump.

In the present invention, the raw material mainly containing magnesium is evaporated in a hydrogen gas atmosphere in the evaporation step. Then, the magnesium hydride is condensed by bringing the evaporated source gas into contact with the condensing part at a temperature lower than the heating temperature of the source. Typical magnesium alloy elements such as manganese Mn and aluminum Al, heavy metal impurities such as iron Fe, nickel Ni, and copper Cu, and metal oxides such as magnesium oxide MgO are removed as a residue because the vapor pressure is sufficiently lower than magnesium. .
Moreover, when the raw material containing the impurity metal whose vapor pressure is higher than magnesium is heated, the impurities are evaporated together with magnesium. In the condensation step, the temperature is adjusted to a temperature lower than the heating temperature of the raw material and higher than the melting point of the impurity metal. Therefore, magnesium hydride is selectively condensed in the condensing part. Preferably, in the condensation step, the temperature is adjusted to a temperature lower than the boiling point of magnesium under a specific pressure condition and higher than the boiling point of the impurity metal. Furthermore, in the condensation step, it is more preferable to adjust the temperature to a temperature lower than the melting point of magnesium under a specific pressure condition and higher than the boiling point of the impurity metal.

  In the present invention, the impurity metal is evaporated by heating the raw material in an inert gas atmosphere, and the evaporated impurity metal is removed together with the inert gas. Therefore, magnesium hydride can be produced from the raw material from which the impurity metal having a higher vapor pressure than magnesium is removed.

In the present invention, it is possible to prevent zinc Zn and zinc hydride ZnH ₂ from condensing in the condensing part.

  In the present invention, it is possible to prevent the magnesium oxide or the like based on the decomposition gas of organic impurities from forming in the condensing part by washing the raw material in advance.

  In the present invention, the shape and surface area of the condensed magnesium hydride can be controlled.

  According to the present invention, high-purity magnesium hydride can be produced by a hydrochemical vapor deposition method using magnesium or an alloy material containing an impurity metal as a raw material.

It is a schematic diagram which shows one structural example of the magnesium hydride manufacturing apparatus which concerns on this Embodiment 1. FIG. It is the figure which showed the thermal equilibrium curve of magnesium and magnesium hydride in hydrogen atmosphere. It is a graph which shows the vapor pressure curve of the various metals contained in a raw material. It is the photograph which showed the external appearance of the magnesium hydride obtained by the hydrogenation chemical vapor deposition method which used AZ91D alloy cutting waste as a raw material. It is the photograph which showed the SEM image of the magnesium hydride obtained by the hydrogenation chemical vapor deposition method which used AZ91D alloy cutting waste as a raw material. It is the X-ray diffraction pattern which showed the X-ray-diffraction (XRD: X-ray diffraction) pattern of the magnesium hydride obtained by the hydrogenation chemical vapor deposition method which used AZ91D alloy and AM60B alloy cutting waste as a raw material. FIG. 6 is a schematic diagram showing a configuration example of a magnesium hydride production apparatus according to Embodiment 2. 5 is a flowchart showing a method for producing magnesium hydride according to Embodiment 2. FIG. 6 is a schematic diagram showing a configuration example of a magnesium hydride production apparatus according to Embodiment 3.

Hereinafter, the present invention will be described in detail with reference to the drawings illustrating embodiments thereof.
(Embodiment 1)
<Configuration of Magnesium Hydride Production Equipment>
FIG. 1 is a schematic diagram showing a configuration example of a magnesium hydride production apparatus according to the present embodiment. The magnesium hydride production apparatus includes an enclosure 1 that contains an impurity metal having a vapor pressure higher than that of magnesium and can enclose a raw material 4 mainly composed of magnesium and high-pressure hydrogen gas. The enclosure 1 is disposed in a heating furnace 2 for heating and evaporating the raw material 4 in a hydrogen gas atmosphere.

The enclosure 1 is a pressure vessel that can maintain the internal atmosphere at high temperature and pressure. The enclosure 1 has, for example, a cylindrical container body 11 and flanges 12 that close both ends. Examples of the material of the enclosure 1 include a heat-resistant metal such as Inconel, and a ceramic containing glass. A placing plate portion 14 on which the raw material 4 is placed is provided at a substantially central portion of the container main body portion 11. On both ends of the container main body 11, a condensing unit 13 is arranged in which the magnesium hydride condenses in contact with the raw material 4 gas evaporated in the hydrogen atmosphere. The arrangement of the condensing unit 13 is not particularly limited as long as it can be kept lower than the heating temperature of the raw material 4, and may be provided on the upper surface or the lower surface of the enclosure 1.
The enclosure 1 includes a high-pressure hydrogen cylinder, a pressure regulator, and the like, and is provided with a hydrogen gas supply unit 32 that supplies high-pressure hydrogen gas into the enclosure 1. Furthermore, the enclosure 1 is provided with a pressure controller 33 that includes a decompressor, a microcontroller, and the like and can control the pressure of the hydrogen gas atmosphere in the enclosure 1 to an arbitrary pressure. Furthermore, the sealed container 1 is provided with a pressure gauge 34 that detects and displays the internal pressure of the sealed container 1.

  The heating furnace 2 includes heating units 21 and 21 for heating the inside of the heating furnace 2, a temperature sensor 22 for detecting the temperature in the enclosure 1, and a temperature sensor 23 for detecting the temperature of the raw material 4. The heating units 21 and 21 are for evaporating the raw material 4 by heating it in a hydrogen gas atmosphere, and are constituted by heaters or induction heating coils made of heating wires. For the temperature sensors 22 and 23, for example, thermocouples are used. The heating units 21 and 21 and the temperature sensors 22 and 23 are connected to a temperature control unit 31 including a power source and a microcontroller for supplying a heating current to the heating units 21 and 21. The temperature control unit 31 can control the temperature of the enclosure 1 and the raw material 4 to an arbitrary temperature.

  Moreover, the magnesium hydride manufacturing apparatus detects the temperature of the temperature control parts 24 and 24 which adjust the temperature of the condensation part 13 to a temperature lower than the heating temperature of the raw material 4 and higher than the melting point of the impurity metal, and the condensation part 13. Sensors 25 are provided. The temperature control units 24 and 24 are, for example, heating wires embedded in the condensing unit 13, and the temperature sensors 25 and 25 are thermocouples. Further, when the condensing unit 13 is disposed at a location where the temperature of the condensing unit 13 is higher than the melting point of the impurity metal by the heating units 21 and 21, an air cooling fan for cooling the condensing unit 13 and a refrigerant are passed. The temperature control sections 24 and 24 may be configured by flow pipes or Peltier elements that are allowed to flow. Furthermore, you may comprise the temperature control parts 24 and 24 combining these so that it can heat and cool. In order to increase the surface area of the condensing part 13, the wall surface may be wedge-shaped or a removable baffle plate may be provided.

<Magnesium hydride production method>
First, the raw material 4 is prepared. The raw material 4 may be low-purity metallic magnesium that does not satisfy industrial standards such as JIS, or is a general-purpose magnesium alloy such as Mg—Al, Mg—Al—Zn, Mg—Al—Si, Mg—Al—RE. , Mg—Zr, Mg—RE (RE: rare earth element), and Mg—Zn—Zr may be used. Further, as the raw material 4, a special magnesium alloy containing Ag or Y may be used. Furthermore, unused materials of these alloys, molding defects such as casting, extrusion, forging, runners, gates, overflows, end materials during pressing, chips during cutting, chemical conversion, painting, plating, anode An oxidized product may be used as the raw material 4.

  And when organic substances, such as cutting oil and a coating film, remain on the surface in the prepared raw material 4, it removes by immersing in a release agent or a degreasing agent. Moreover, as pre-processing which removes the organic substance, oxide, or hydroxide which remain | survives on the surface of the raw material 4, it immerses for a short time in the organic acid or inorganic acid of pH = 1-3. The type of acid is not particularly limited, and hydrochloric acid, citric acid and the like can be used. However, if the pH is too low, the raw material 4 is often dissolved, which is not economical. When the pH is high, the treatment time becomes long. Mechanical polishing with loose abrasive grains such as abrasive paper and blasting can also be used. And the raw material 4 which finished washing | cleaning is cut | disconnected below to the magnitude | size which enters the enclosure 1.

Next, a sealed container 1 having a heat resistance and a pressure resistance of 1 MPa or more is maintained, and the pretreated raw material 4 is placed on the dish portion 14 in the sealed container 1 and sealed. And hydrogen gas is supplied to the enclosure 1 and the raw material 4 is heated to 600-700 degreeC by the heating parts 21 and 21 under hydrogen atmosphere. The pressure control unit 33 controls the hydrogen pressure in the enclosure 1 to 4 MPa, for example. The hydrogen purity is not specified, but it is preferably 99.99% or more. Further, the temperature of the condensing unit 13 is adjusted by the temperature control units 24 and 24. The temperature of the condenser 13 varies depending on the hydrogen gas pressure, the coexisting metal component in the raw material 4 described later, and the type of impurities.
FIG. 2 is a diagram showing a thermal equilibrium curve between magnesium and magnesium hydride under a hydrogen atmosphere. In the figure, it is divided into two regions by a curve crossing from the lower left to the upper right. Region I is a stable state of magnesium Mg and hydrogen H ₂ , respectively, and region II is a stable state of magnesium hydride MgH ₂ . The temperature of the condenser 13 is adjusted to the shaded area in the figure. From a practical point of view, a lower hydrogen pressure is desirable. Magnesium hydride is deposited in the condensing part 13 provided in the enclosure 1 by adjusting the temperature to 400 to 500 ° C. under a hydrogen pressure lower than 6 MPa.

  FIG. 3 is a graph showing vapor pressure curves of various metals contained in the raw material 4. The horizontal axis indicates the temperature, and the vertical axis indicates the vapor pressure of each metal at the temperature. Both draw a rising curve, and the higher the vapor pressure at a certain temperature, the easier the metal evaporates. Typical magnesium alloy elements such as manganese Mn and aluminum Al, heavy metal impurities such as iron Fe, nickel Ni and copper Cu, and metal oxides such as magnesium oxide have a vapor pressure sufficiently lower than that of magnesium, so the evaporation temperature is 600 to 700. If set to ° C., it is removed as a residue. Mg-9Al-0.7Zn-0.3Mn (AZ91D alloy), which is a general-purpose alloy, contains about 0.5 to 0.9% by weight of zinc Zn. Since the vapor pressure of zinc Zn is close to that of magnesium, care must be taken so that zinc or zinc hydride does not condense in the condensing part 13. Specifically, the partial pressure of zinc in the enclosure 1 is adjusted to be less than the vapor pressure of zinc at the temperature of the condensing unit 13.

  In addition, the shape of the magnesium hydride as a precipitate is adjusted by the heating temperature of the raw material 4, the temperature of the condensing unit 13, or the pressure in the enclosure 1. Although the reaction time depends on the required yield and the shape of the enclosure 1, 1 to 40 hours is appropriate.

As described above, in the magnesium hydride manufacturing method and the magnesium hydride manufacturing apparatus according to the first embodiment, a hydrogen chemical vapor deposition method using magnesium or an alloy material containing an impurity metal such as zinc as the raw material 4 is used. High-purity magnesium hydride can be produced.
Moreover, since the low-grade magnesium such as low-purity magnesium metal or magnesium alloy scrap is used as the raw material 4, the cost and energy required for production can be greatly reduced.

  Furthermore, the magnesium hydride production apparatus and the magnesium hydride production method according to the present invention are advantageous in that magnesium fine particles can be produced instead of a magnesium ingot, and the hydrogenation rate can be reduced as compared with conventional methods. Therefore, the magnesium evaporation process by reheating the ingot, which was necessary in the conventional method, is not necessary, and magnesium hydride can be produced efficiently.

  In the first embodiment, the evaporation process and the hydrogenation process of the raw material 4 are performed in the same container, but both may be performed in different reaction chambers or may be performed in stages.

  Moreover, in Embodiment 1, although the plate | board part 14 is made into the high temperature part and the condensation part 13 is made into the low temperature part, in order to accelerate | stimulate mass transfer, you may provide a gentle temperature gradient in a high temperature part and a low temperature part. For example, several band heaters are attached between the low temperature part and the high temperature part, and the temperature gradient is adjusted by the heater temperature.

Example 1
The example which manufactures a magnesium hydride using AZ91D alloy and AM60B alloy cutting waste as the raw material 4 is demonstrated. Table 1 shows the chemical composition of AZ91D alloy and AM60B alloy cutting waste in weight%. Chemical components were analyzed using an inductively coupled plasma-atomic emission spectrometer (ICP-AES). Both AZ91D alloy and AM60B alloy cutting waste are within the standard values of JIS.

As a pretreatment, the raw material 4 was immersed in 0.1 mol / L hydrochloric acid for several seconds, washed with ethanol, and dried under vacuum. Samples that were not pretreated were also subjected to the test. 2 g of raw material 4 was put into the Inconel enclosure 1 and set to high-pressure hydrogen PH ₂ having a purity of 99.99999%. The starting material 4 was heated from the outside to 600 ° C. with a heating resistor and kept at a hydrogen pressure of 4 MPa for 20 hours. A flange made of Inconel maintained at a low temperature T = 400 to 500 ° C. was provided on the side of the enclosure 1 to deposit magnesium hydride.

  FIG. 4 is a photograph showing the appearance of magnesium hydride obtained by the hydrogenation chemical vapor deposition method using AZ91D alloy cutting waste as raw material 4, and FIG. 5 is a photograph showing the SEM image. Magnesium hydride exhibited a fibrous shape having an average diameter of 1 μm or less and a length of 10 μm or more.

FIG. 6 is an X-ray diffraction diagram showing an X-ray diffraction (XRD) pattern of magnesium hydride obtained by a hydrogenation chemical vapor deposition method using AZ91D alloy and AM60B alloy cutting waste as raw material 4. . As a reference, the results with a commercially available magnesium hydride reagent (Alfa Aesar) are also shown. The horizontal axis is the diffraction angle, and the vertical axis is the diffraction intensity. Square marks diffraction peak of magnesium hydride MgH _2, circles diffraction peak of magnesium oxide MgO, rhombuses indicates the diffraction peak of magnesium Mg. 6A and 6B are X-ray diffraction diagrams when AZ91D alloy and AM60B alloy are used as raw material 4 without pretreatment, and FIGS. 6C and 6D show X when AZ91D alloy and AM60B alloy are used as raw material 4 with pretreatment. FIG. 6E is an X-ray diffraction diagram when a commercially available magnesium hydride reagent is used as the raw material 4.

  As shown in FIG. 6E, unreacted magnesium was detected in the commercially available magnesium hydride. In contrast, as shown in FIGS. 6A to 6D, such a peak is not observed in the magnesium hydride obtained by the HCVD method. Further, when no pretreatment is performed, magnesium oxide is detected as shown in FIGS. 6A and 6B. By performing the pretreatment, it can be seen that a high-purity magnesium hydride can be obtained even when the AZ91D alloy and the AM60B alloy are used as the starting material 4.

Here, the influence which zinc contained in magnesium hydride has on hydrogen storage and release performance will be described. Using AZ91D alloy cutting waste as raw material 4, the zinc concentration in the magnesium hydride obtained under the above-mentioned conditions was 0.2% by weight. For comparison, a HCVD method was applied under the condition of a deposition temperature of 400 ° C. using a sample in which pure zinc powder was mixed with pure magnesium powder at a ratio of 10: 2. When the XRD pattern of the obtained sample was measured, the peak of the zinc magnesium compound was detected in addition to the magnesium hydride. The dehydrogenation behavior of this sample and a magnesium hydride sample having a zinc concentration of 0.2% by weight was investigated by TGmass (TGA / DSC1-0804JPN, METLER TOLEDO STAR ^e System). As a result, the weight loss (hydrogen release amount) accompanying high-temperature heating was 4.8% by weight and 6.8% by weight, respectively. The small value of the former is due to the presence of zinc components that are not involved in hydrogen storage / release. Therefore, it is necessary to make the zinc content as low as possible.

(Example 2)
A test was conducted in which the average temperature of the condenser 13 was adjusted to less than 410 and 420 ± 10, 445 ± 15 ° C. under the conditions shown in Example 1, and magnesium hydride was produced using AZ91D alloy cutting waste as the raw material 4. It was. Table 2 below shows the concentration of zinc contained in the magnesium hydride obtained by adjusting the average temperature of the condenser 13 to less than 410, 420 ± 10, 445 ± 15 ° C. in weight%. .

  As can be seen from Table 2, the zinc concentration can be reduced to 0.02% by weight by setting the temperature of the condensing part 13 to a higher value of 445 ± 15 ° C.

  Currently, most of the magnesium alloys on the market as lightweight structural materials are AZ91D alloy and AM60B alloy shown in Table 1. Both can be easily identified by the recycle mark stamped on the product. Therefore, if an AM60B alloy containing almost no zinc is used as the starting material 4, a high-quality magnesium hydride can be obtained even when the temperature of the low temperature portion is 400 ° C. When an AZ91D alloy containing about 1% by weight of zinc is used for the starting material 4, the magnesium hydride having an equivalent quality can be obtained by slightly raising the temperature of the low temperature portion, for example, 430 ° C. or higher.

(Embodiment 2)
<Configuration of Magnesium Hydride Production Equipment>
FIG. 7 is a schematic diagram illustrating a configuration example of a magnesium hydride production apparatus according to Embodiment 2. The magnesium hydride production apparatus according to Embodiment 2 is a vertical type including a vertically long cylindrical enclosure 101 that can enclose the raw material 4 and high-pressure hydrogen gas, and has a space-saving configuration.

  The sealed container 101 includes, for example, a bottomed cylindrical container main body 111 having an opening in the upper part and a lid part 112 that closes the upper opening. The material of the enclosure 101 is the same as that of the enclosure 1 of the first embodiment. A first block heater 121 a for heating the inside of the sealed container 101 is disposed at the bottom of the container body 111, and a first temperature sensor that detects the temperature in the sealed container 101, particularly the temperature of the bottom of the container body 111. 122a is provided. On the upper surface of the first block heater 121a, a placing plate portion 114 on which the raw material 4 is placed is provided. In addition, a plurality of second block heaters (temperature control units) 122b are arranged on the outer peripheral surface of the container main body 111 in the circumferential direction and the longitudinal direction, and the temperatures at the locations where the second block heaters 121b are respectively provided. The 2nd temperature sensor 122b which detects this is provided. The first and second block heaters 121 a and 121 b and the first and second temperature sensors 122 a and 122 b are connected to the temperature control unit 131. The temperature control unit 131 includes a power source and a microcontroller for supplying a heating current to the first and second block heaters 121a and 121b. The temperature controller 131 controls the energization amount to the first and second block heaters 121a and 121b based on the temperatures detected by the first and second temperature sensors 122a and 122b, and the temperature of each part in the sealed container 101. Can be controlled arbitrarily. For example, the temperature controller 131 can generate a temperature gradient from the lower part to the upper part of the enclosure 101.

  Further, a condensing part 113 is arranged in the longitudinal direction of the container main body 111, from the substantially central part to the upper inner peripheral surface, in contact with the raw material 4 gas evaporated in the hydrogen atmosphere to condense magnesium hydride. The condensing part 113 is cylindrical and has unevenness on the inner peripheral surface side. The unevenness has, for example, a wedge shape in cross section.

  Furthermore, the sealed container 101, for example, the lid 112, includes a high-pressure hydrogen cylinder, a pressure regulator, and the like, and a hydrogen gas supply unit 132 that supplies high-pressure hydrogen gas into the sealed container 101 and a non-filled container 101. An inert gas supply unit 135 that supplies active gas is connected via a three-way valve 136. The type of gas supplied to the enclosure 1 can be switched by the three-way valve 136. The three-way valve 136 may be switched manually or automatically by a control circuit (not shown).

  Furthermore, an impurity trap 138 that supplements impurities, for example, zinc, is connected to the sealed container 101, for example, the lid portion 112, via an on-off valve 137. The impurity trap 138 is connected to a vacuum pump 139 that exhausts the gas in the sealed container 101, particularly exhausts the gas of zinc contained in the raw material 4.

  Furthermore, the sealed container 101, for example, the lid 112, includes a pressure gauge 134 that detects and displays the internal pressure of the sealed container 101, and a pressure control unit that controls the pressure of the hydrogen gas atmosphere in the sealed container 101 to an arbitrary pressure. 133 is provided.

<Magnesium hydride production method>
FIG. 8 is a flowchart showing the method for producing magnesium hydride according to the second embodiment. The pretreatment, cutting, and sealing process of the raw material 4 in the sealing container 101 are the same as those in the first embodiment. Table 3 below shows the temperature of the raw material 4 and the condensing unit 113 and the type of gas supplied to the enclosure 101 in the subsequent steps.

  As shown in Table 3, first, an inert gas is supplied to the enclosure 101 and the raw material 4 is heated at 430 to 460 ° C. Further, the temperature of the condenser 113 is adjusted to 445 ± 15 ° C. Since the melting point of zinc is 420 ° C., the melting point of magnesium is 650 ° C., and the vapor pressure of zinc is higher than that of zinc, heating the raw material 4 at a low temperature mainly evaporates the zinc, and the impurity trap 138 from the enclosure 1. Inert gas containing a large amount of zinc can be discharged. In order to accelerate the evaporation of zinc, the inside of the enclosure 1 may be brought into a reduced pressure state of about 10 kPa using a vacuum pump 139. By this treatment, the raw material 4 can be highly purified. The temperature control unit 131 is configured so that the first and second block heaters 121a and 121b, and the first and second temperature sensors 122a and 122b are used to change the temperature from the location where the raw material 4 of the container 101 is disposed over the condensing unit 113. Generate a gradient.

  Next, hydrogen gas is supplied to the enclosure 101 and the raw material 4 is heated to 600 to 700 ° C. by the first block heater 121a in a hydrogen atmosphere. Further, the temperature of the condensing unit 113 is adjusted to 445 ± 15 ° C. by the second block heater 121b. By setting the condensing unit 113 to 445 ± 15 ° C., magnesium hydride can be condensed in the condensing unit 113 while preventing the zinc remaining in the raw material 4 from condensing.

  In the magnesium hydride production method and the magnesium hydride production apparatus according to Embodiment 2, zinc can be removed from the raw material 4 by a simple treatment, and a higher purity magnesium hydride can be produced.

(Embodiment 3)
FIG. 9 is a schematic diagram illustrating a configuration example of a magnesium hydride production apparatus according to Embodiment 3. The magnesium hydride manufacturing apparatus according to the third embodiment has the same configuration as that of the second embodiment. Furthermore, the container body 111 of the enclosure 1 is condensed with the first space 111a on the first block heater 121a side. A gate valve 251 is provided to be separated from the second space 111b on the part 113 side. The first space 111a is a high temperature space, and the second space 111b is a low temperature space. In addition, the magnesium hydride manufacturing apparatus includes a gate valve control unit 252 that controls opening and closing of the gate valve 251. The vacuum pump 139 is connected to the second space 111b side of the container body 111.

  In the evaporation step of Embodiment 3, the first space 111a in which the raw material is heated in the hydrogen gas atmosphere is separated from the second space 111b in which the magnesium hydride is condensed in a state where the gate valve 251 is closed. In this state, the temperature of the first space 111a is slightly increased, for example, maintained at 450 to 460 ° C. to promote the evaporation of the raw material 4 and the Mg hydrogenation reaction. Then, after the lapse of a certain time, in the condensation process, the first space 111a and the second space 111b are communicated by opening the gate valve 251, and further, the pressure of the second space 111b is made higher than the pressure of the first space 111a. In this state, the vapor of the raw material 4 is transferred to the second space 111b. At this time, the second space 111b is kept at a temperature lower than that of the first space 111a, for example, 440 ± 10 ° C. In addition, the vacuum pump 139 is operated to set the pressure in the second space 111b slightly lower than the pressure in the first space 111a. By adjusting the pressure in the second space 111b, the shape and surface area of the magnesium hydride can be controlled. While the aggregation reaction of magnesium hydride is caused in the second space 111b, the first space 111a may be moved to the next batch process. In addition, although the container main-body part 111 was divided | segmented by the 1st space 111a and the 2nd space 111b here, you may comprise as an independent container, respectively. Moreover, it is good also as a mechanism which controls each hydrogen pressure.

  According to Embodiment 3, the shape and surface area of the condensed magnesium hydride can be controlled.

  The embodiment disclosed this time is to be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the meanings described above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  The present invention can be used in the magnesium recycling field, energy field, fuel cell field, nanotechnology field, metal forming field, and medical / health / beauty field.

DESCRIPTION OF SYMBOLS 1,101 Enclosed container 2 Heating furnace 4 Raw material 11,111 Container body part 12 Flange part 13,113 Condensing part 14,114 Dish part 21 Heating part 22,23,25 Temperature sensor 24 Temperature control part 31,131 Temperature control part 32 , 132 Hydrogen gas supply unit 33, 133 Pressure control unit 34, 134 Pressure gauge 111a First space 111b Second space 112 Lid 121a First block heater 121b Second block heater (temperature control unit)
122a 1st temperature sensor 122b 2nd temperature sensor 135 inert gas supply part 136 three-way valve 137 on-off valve 138 impurity trap 139 vacuum pump 251 gate valve 252 gate valve control part

Claims (7)

An evaporation step including an impurity metal having a higher vapor pressure than magnesium and evaporating a raw material mainly composed of magnesium by heating in a hydrogen gas atmosphere;
A condensing step of condensing magnesium hydride by contacting the evaporated raw material gas with a condensing part having a temperature lower than the heating temperature of the raw material,
The condensation step includes
A method for producing magnesium hydride, wherein the temperature of at least a part of the condensing part is adjusted to a temperature lower than a heating temperature of the raw material and higher than a melting point of the impurity metal. Before the evaporation step, heating the raw material in an inert gas atmosphere to evaporate the impurity metal contained in the raw material;
The method of removing the vapor | steam of the impurity metal which evaporated, The magnesium hydride manufacturing method of Claim 1 characterized by the above-mentioned. The raw material includes zinc;
The said condensation process heats the said condensation part to 400-500 degreeC. The magnesium hydride manufacturing method of Claim 1 or Claim 2 characterized by the above-mentioned. The method for producing a magnesium hydride according to any one of claims 1 to 3, further comprising a step of washing the raw material with an acid before heating the raw material. The evaporation step includes
In a state where the first space where the raw material is heated in a hydrogen gas atmosphere and the second space where the magnesium hydride is condensed are separated, the raw material is evaporated,
The condensation step includes
The magnesium hydride is condensed in a state where the first space communicates with the second space and the pressure in the second space is lower than the pressure in the first space. The method for producing magnesium hydride according to claim 4. An enclosure that contains an impurity metal having a higher vapor pressure than magnesium and encloses a raw material mainly composed of magnesium in a hydrogen gas atmosphere;
A hydrogen gas supply unit for supplying hydrogen gas into the enclosure;
A heating section for evaporating the raw material by heating in a hydrogen gas atmosphere;
A condensing part where magnesium hydride condenses in contact with the evaporated source gas;
A magnesium hydride manufacturing apparatus comprising: a temperature control unit configured to adjust a temperature of at least a part of the condensing unit to a temperature lower than a heating temperature of the raw material and higher than a melting point of the impurity metal. A gate valve separating the first space on the heating unit side and the second space on the condensation unit side;
The magnesium hydride manufacturing apparatus according to claim 6, further comprising: a vacuum pump connected to the second space side of the enclosure.