KR20040048356A - Process and apparatus for producing high purity magnesium oxide fine particles - Google Patents

Abstract

PURPOSE: A method and an apparatus for producing high-purity magnesium oxide fine powder are provided to obtain high-purity magnesium oxide fine powder having a narrow particle size distribution for a long period of time in a continuous manner. CONSTITUTION: The method for producing high-purity magnesium oxide fine powder comprises the steps of: contacting oxygen-containing gas flow with a mixed gas formed of magnesium vapor and inert gas, sprayed upwardly and substantially vertically, to oxidize magnesium, thereby forming magnesium oxide fine powder, while collecting a part of the resultant magnesium oxide fine powder continuously or intermittently to determine characteristic values related with particle diameter of the powder; and adjusting the flow and/or concentration of the oxygen-containing gas based on the determined values, so that the particle diameter of the resultant magnesium oxide fine powder is controlled to be in a predetermined range of particle diameters.

Description

Manufacturing method and apparatus of high purity magnesium oxide fine powder {PROCESS AND APPARATUS FOR PRODUCING HIGH PURITY MAGNESIUM OXIDE FINE PARTICLES}

The present invention relates to a method and apparatus for producing high purity magnesium oxide fine powder.

As a method for producing high purity magnesium oxide fine powder, a gas phase synthesis method is known. This gas phase synthesis method is a method of heating magnesium metal to generate magnesium vapor, and contacting each other with magnesium oxide and oxygen-containing gas to oxidize magnesium to produce fine magnesium oxide powder.

The apparatus for producing magnesium oxide fine powder by vapor phase synthesis method is generally a magnesium vapor generating device for producing metal magnesium vapor, and a magnesium oxide device for producing magnesium oxide fine powder by oxidizing magnesium by bringing magnesium vapor and oxygen-containing gas into contact with each other. Is made of.

Japanese Unexamined Patent Application Publication No. Hei 2-307822, which is a magnesium vapor generating apparatus, has a structure in which a metal magnesium melting port for heating and melting metal magnesium and a magnesium evaporation port for heating and evaporating molten magnesium are connected by heat-resistant connection pipes. Metal magnesium melt evaporation apparatus is disclosed.

Japanese Laid-Open Patent Publication No. 7-101722 is a magnesium oxide device, including a mixed gas injection port for injecting a mixed gas composed of magnesium vapor and an inert gas from the bottom to an upward direction, and having an oxygen-containing gas injection port at the side. Disclosed is a magnesium oxide device. In this publication, the cross-sectional area of the mixed gas jet port is set so as to have a desired particle size, and then, magnesium oxide powder is produced by a real apparatus, and the difference between the set particle diameter and the particle size of the powder actually obtained is changed by changing the mounting position of the oxygen-containing gas jet port. There is a description that it is possible to manufacture magnesium oxide powder of a desired particle size accurately by adjustment.

According to the research of the present inventors, it was found that there are some problems when the fine magnesium oxide powder is actually manufactured by using the above-mentioned magnesium magnesium evaporation apparatus and the magnesium oxide apparatus. One of them, if the magnesium oxide fine powder is continuously produced over a long period of time, the magnesium oxide fine powder having an irregular particle diameter tends to be easily formed with the passage of the production time, and the width of the particle size distribution of the obtained high purity magnesium oxide fine powder is increased. There is a problem that is widened. In addition, it has been found that there is a problem that the purity of the obtained magnesium oxide fine powder may decrease when the magnesium oxide fine powder is continuously produced over a long period of time.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method and apparatus for producing a high purity magnesium oxide fine powder having a narrow width of particle size distribution continuously over a long period of time by eliminating the problems described above.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows an example of the structure of the high purity magnesium oxide fine powder collection | recovery apparatus for implementing the method of this invention.

FIG. 2 is an enlarged view of a peripheral portion of a magnesium vapor injection hole of a magnesium oxide device which is a feature of the high purity magnesium oxide fine powder production device of FIG. 1.

3 is a view showing another example of the configuration of a high-purity magnesium oxide fine powder production and recovery apparatus using the high-purity magnesium oxide fine powder production apparatus according to the present invention.

FIG. 4 is an enlarged view of a peripheral portion of a magnesium vapor injection hole of a magnesium oxide device which is a feature of the high purity magnesium oxide fine powder production device of FIG. 3.

According to the present invention, a portion of the resulting magnesium oxide fine powder is continuously produced while the magnesium oxide fine powder is oxidized by oxidizing magnesium by bringing an oxygen-containing gas stream into contact with a mixed gas composed of magnesium vapor and an inert gas sprayed substantially vertically upward. Alternatively, the intermittent sample may be collected intermittently to measure the property value related to the particle size, and the flow rate and / or the oxygen concentration of the oxygen-containing gas may be adjusted based on the measured property value so that the particle size of the fine magnesium oxide powder is made to fall within the predetermined particle size range. There is a method for producing a high-purity magnesium oxide fine powder consisting of adjusting.

The present invention also relates to a metal magnesium melting port having a metal magnesium inlet at the top and a molten magnesium outlet at the bottom of the side, a heat resistant pipe connected to the molten magnesium outlet of the melting port, and the other heat resistant pipe. A molten magnesium inlet connected to the end is provided at the lower side of the side, and a magnesium magnesium evaporation device comprising a magnesium evaporation port having a magnesium vapor outlet at the top thereof, and a magnesium vapor outlet of the evaporation port at the bottom thereof. Magnesium oxidizer equipped with a magnesium vapor injection port, an oxygen-containing gas injection port on the side, and a fine magnesium oxide powder outlet on the upper side, the magnesium oxide device has an internal observation window on the side, and magnesium vapor parallel to the bottom Metal magnesium or magnesium compound deposited at the nozzle May also grinding device is laid high purity magnesium oxide powder producing apparatus, characterized in that to remove.

The invention also relates to a metal magnesium melting port having a metal magnesium inlet at the top and a molten magnesium outlet at the bottom of the side, a heat resistant pipe connected to the molten magnesium outlet of the melting port, and a second end of the heat resistant pipe. A magnesium magnesium evaporation device comprising a magnesium evaporation port having a molten magnesium inlet at the lower side and a magnesium evaporation port at the top, and a magnesium vapor inlet connected at the bottom to the magnesium vapor outlet at the bottom. And a magnesium oxide device having an oxygen-containing gas injection port at the side and a magnesium oxide fine powder outlet at the top, and a heater for heating the surroundings of the magnesium vapor injection port at the bottom of the magnesium oxide device is provided. Magnesium Fine Powder Manufacturing Equipment There is also.

The present invention also relates to a metal magnesium melting port having a metal magnesium inlet at the top and a molten magnesium outlet at the bottom of the side, a heat resistant pipe connected to the molten magnesium outlet of the melting port, and the other end of the heat resistant pipe. It is composed of a magnesium evaporation port having a molten magnesium inlet at the lower side of the side and a magnesium vapor outlet at the top, and the distance from the molten magnesium inlet to the bottom of the evaporation port is from the molten magnesium outlet of the molten port to the bottom. There is also a metal magnesium melt evaporation apparatus, characterized in that it is longer than the distance of.

The invention also relates to a metal magnesium melting port having a metal magnesium inlet at the top and a molten magnesium outlet at the bottom of the side, a heat resistant pipe connected to the molten magnesium outlet of the melting port, and a second end of the heat resistant pipe. A molten magnesium inlet is provided at the lower side of the side and a magnesium evaporation port having a magnesium vapor outlet at the top thereof, and a molten magnesium outlet is formed at the bottom of the evaporation port to open and close the molten magnesium. It is also in the device.

Detailed description of the invention

The preferable aspect of the high purity magnesium oxide fine powder manufacturing apparatus of this invention is shown below.

(1) The contact angle between the mixed gas and the oxygen-containing gas is approximately perpendicular to the direction of travel of the mixed gas.

(2) The physical property value related to particle diameter is a specific surface area.

(3) A step of adjusting the particle size of the fine magnesium oxide powder produced by adjusting the contacting position of the mixed gas and the oxygen-containing gas.

The preferable aspect of the high purity magnesium oxide fine powder manufacturing apparatus of this invention is shown below.

(1) At the bottom of the magnesium oxidation apparatus, a heater is provided for heating the surroundings of the magnesium vapor jet port together with the grinding apparatus.

The preferable aspect of the metal magnesium melt evaporation apparatus of this invention is shown below.

(1) A molten magnesium outlet is formed at the bottom of the evaporation port where the distance from the molten magnesium inlet to the bottom is adjusted.

In the method for producing a high-purity magnesium oxide fine powder of the present invention, while producing a fine magnesium oxide powder, a portion of the produced magnesium oxide fine powder is continuously or intermittently taken to measure the physical property value related to the particle diameter, and based on the measured physical property value By adjusting the flow rate and / or oxygen concentration of the containing gas, it is characterized in that the particle size of the resulting magnesium oxide fine powder is adjusted to fall within the predetermined particle size range.

As a physical property value related to particle diameter, an average particle diameter and specific surface area (BET specific surface area) can be used. A well-known method, such as a laser diffraction method, can be used for the measurement of an average particle diameter. A well-known method, such as a nitrogen adsorption method, can be used for the measurement of a specific surface area. It is preferable to use a specific surface area for the physical property value which concerns on a particle diameter.

The measurement of the physical property value is preferably carried out at a frequency of two or more times (preferably 2 to 10 times) per hour immediately after the start of production (usually within 5 hours from the start of production) where the particle size of the fine magnesium oxide powder is likely to become unstable. Do. Moreover, even when the particle size of magnesium oxide fine powder is comparatively stable, it is preferable to perform a measurement of a physical property at the frequency of 1 or more times (preferably 1 to 5 times) per hour.

When the particle size of the fine magnesium oxide powder is larger than the target particle size range, the flow rate of the oxygen-containing gas is higher than before adjustment, and the oxygen concentration of the oxygen-containing gas is higher than before adjustment. On the other hand, when the particle diameter is smaller than the target particle size range, the flow rate of the oxygen-containing gas is lower than before adjustment, and the oxygen concentration of the oxygen-containing gas is lower than before adjustment.

In this invention, you may use together the method of adjusting the contact place of a mixed gas and an oxygen containing gas as a method of adjusting the particle diameter of the produced magnesium oxide fine powder. In this method, when the particle size of the fine magnesium oxide powder is larger than the target particle size range, the contact point of the mixed gas and the oxygen-containing gas is set to a lower position than before the adjustment. On the other hand, when the particle diameter is smaller than the target particle size range, the contact place between the mixed gas and the oxygen-containing gas is set to a position higher than before the adjustment. It is preferable to adjust the place of contact of the mixed gas and the oxygen-containing gas by changing the arrangement position of the oxygen-containing gas injection port.

EMBODIMENT OF THE INVENTION Hereinafter, the manufacturing method of the high purity magnesium oxide fine powder of this invention is demonstrated, referring an accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows an example of the structure of the high purity magnesium oxide fine powder collection | recovery apparatus for implementing the method of this invention. 2 is an enlarged view of the peripheral portion of the magnesium vapor injection port of the magnesium oxide device, which is a feature of the high purity magnesium oxide fine powder production device of FIG.

The high purity magnesium oxide fine powder production and recovery apparatus shown in FIG. 1 includes a high purity magnesium oxide fine powder production apparatus comprising a metal magnesium melt evaporation apparatus 10 and a magnesium oxidation apparatus 26, a heat exchanger 41, a bug filter 42, and It is comprised by the high purity magnesium oxide fine powder collection | recovery apparatus which consists of hoppers 43. As shown in FIG.

The metal magnesium melt evaporation apparatus 10 includes a lid 13 having a metal magnesium inlet 11 and an oxidation gas inlet 12 for preventing oxidation of the metal magnesium, and a molten magnesium outlet at the lower side of the metal magnesium inlet 11. The metal magnesium melting port 16 which consists of the port part 15 provided with the 14, the heat resistant pipe 17 connected to the molten magnesium outlet of the melting port, and the molten magnesium inlet 18 connected to the other end of the heat resistant pipe. ) And a lid portion 22 having a port portion 19 provided at the lower side of the side, and an inert gas inlet 21 for preventing the oxidation of the magnesium vapor outlet 20 and the metal magnesium and diluting the magnesium vapor. It consists of the magnesium evaporation port 23 which consists of.

As the antioxidant gas introduced into the melting port from the antioxidant gas inlet 12 of the melting port cover part, sulfur hexafluoride gas, carbon dioxide gas, neon gas, argon gas, krypton gas, xenon gas, and radon gas may be used. . Among these gases, sulfur hexafluoride gas is particularly preferable. This antioxidant gas is always introduced into the melting pot during the production of magnesium vapor.

Helium gas, neon gas, argon gas, krypton gas, xenon gas, and radon gas may be used as the inert gas introduced into the evaporation port from the inert gas inlet 21 of the evaporation port cover part. Among these gases, argon gas is particularly preferable. This inert gas is always introduced into the evaporation port when magnesium vapor is produced.

The production of magnesium vapor takes place as follows. First, the metal magnesium 24 used as a raw material is thrown into the melting port 16 from the metal magnesium introduction port 11, and the metal magnesium is heated at the melting temperature to the molten magnesium 25 in the melting port. This molten magnesium is stored in the evaporation port 23 through the heat resistant pipe 17. Then, the molten magnesium 25 is heated again at the evaporation port 23 to a temperature above the boiling point to generate magnesium vapor. This magnesium vapor is discharged from the magnesium atomization port 20 of the evaporation port as a mixed gas with an inert gas introduced into the evaporation port from the inert gas inlet 21.

When magnesium steam is produced continuously for a long time, impurities in metal magnesium (especially high boiling point heavy metals such as iron, nickel, and chromium) gradually accumulate in the evaporation port, and impurities increase in the magnesium vapor as the accumulation amount increases. The purity of the fine magnesium oxide powder obtained by mixing may fall. For this reason, in the metal magnesium fusion evaporation apparatus of FIG. By staying at the bottom, it is possible to reduce the amount of impurity mixed with magnesium vapor over a long period of time. The distance from the molten magnesium inlet port to the bottom of the evaporation port is preferably in the range of 1.2 to 1.8 times the distance from the molten magnesium outlet of the melting port to the bottom.

Further, the molten magnesium outlet may be formed to be longer than the distance from the molten magnesium outlet of the melting pot to the bottom, or to be opened and closed at the bottom of the melting pot without adjusting such distance.

The magnesium oxide oxidizer 26 is a mixture gas injection port 27 of magnesium vapor and an inert gas connected to the magnesium vapor outlet 20 of the evaporation port at the bottom, an oxygen-containing gas injection port 28 at the side, and fine magnesium oxide powder at the top. The ejection opening 29 is provided.

The mixed gas injection port 27 is arranged so that the mixed gas of magnesium vapor and the inert gas is vertically upwardly injected. The oxygen-containing gas injection port 28 is arranged to inject the oxygen-containing gas approximately perpendicular to the traveling direction of the mixed gas injected from the mixed gas injection port 27. The magnesium oxide fine powder outlet 29 is disposed above the mixed gas injection port so that the produced magnesium oxide fine powder can be taken out by the flow of the inert gas introduced with the magnesium vapor.

As the oxygen-containing gas, air is usually used. However, the oxygen-containing gas is not limited to air. For example, oxygen may be used alone, or an inert gas (usually argon gas) may be added to oxygen or air.

The internal temperature of the magnesium oxide oxidizer 26 (that is, the oxidation reaction temperature of magnesium) is preferably set to 1200 to 2000 ° C. However, since the oxidation of magnesium is an exothermic reaction, the internal portion of the magnesium oxidizer is produced by the production of fine magnesium oxide powder. The temperature tends to rise. For this reason, the vicinity of the site where the magnesium vapor and the oxygen-containing gas contact each other is covered with a cooling exterior 32 having a cooling air inlet 30 and a cooling air exhaust port 31. The internal temperature of the magnesium oxide can be adjusted by introducing cooling air.

In the magnesium oxide apparatus, metal magnesium or magnesium compound (e.g. magnesium oxide) is deposited around the mixed gas injection port 27, and the amount of finely mixed magnesium oxide powder produced by varying the amount of mixed gas introduced into the apparatus from the mixed gas injection port 27 is generated. The particle diameter may vary. For this reason, in the magnesium oxidation apparatus of FIG. 1, the grinding | polishing apparatus 34 which has the window 33 for internal observation in the side part, and removes the magnesium oxide deposited at the mixed gas injection port parallel to the bottom part is provided.

The grinding device 34 is composed of an arm 36 having a grinding plate 35 at its tip, and a cylinder 37 for pushing the arm in parallel with the bottom of the magnesium oxide device. In addition, in the magnesium oxidation apparatus of FIG. 1, although the internal observation window 33 and the grinding device 34 are each mounted integrally with the hollow casing body 38, the internal observation window and the grinding device are arranged. There is no restriction in particular. The operating speed of the arm 36 of the grinding device 34 is appropriately adjusted in consideration of the deposition state of the metal magnesium or magnesium compound observed by the window 33 for internal observation. The metal magnesium or magnesium compound removed by the grinding device 34 can be taken out to the outside by an opening (cleaning window) 39 provided on the side of the magnesium oxide device.

The internal observation window 33 is a window for visually observing the deposition state of the metal magnesium or magnesium compound around the magnesium vapor injection port 27. The operating speed of the arm 36 of the grinding device 34 is appropriately adjusted in consideration of the deposition state of magnesium oxide observed through this inner viewing window.

In the magnesium oxidizing apparatus of FIG. 1, the oxygen-containing gas is injected from the magnesium-vapor injection port 27 through the oxygen-containing gas injection port 28, and the magnesium-vapor fine powder 40 is brought into contact with the magnesium vapor by contacting it. At the same time, the magnesium oxide deposited around the magnesium vapor jet port can be removed by the grinding device 34 while observing the surroundings of the magnesium vapor jet port from the internal observation window 33. Therefore, the amount of magnesium vapor introduced into the magnesium oxide device from the magnesium vapor injection port is stabilized for a long time.

The magnesium oxide fine powder 40 produced in the magnesium oxide apparatus is sent to the heat exchanger 41 through the magnesium oxide fine powder outlet 29. The fine magnesium oxide powder cooled by the heat exchanger 41 is recovered by the bug filter 42 and once stored in the hopper 43.

Magnesium oxide fine powder produced by gas phase synthesis has high activity, so that in contact with air, carbon dioxide or water vapor in the air may be adsorbed. For this reason, it is preferable to refire the magnesium oxide fine powder stored in the hopper at the temperature of 500-1100 degreeC before shipment.

3 is a view showing another example of the configuration of a high-purity magnesium oxide fine powder production recovery apparatus using a high-purity magnesium oxide fine powder production apparatus according to the present invention, Figure 4 is a magnesium oxide device which is a feature of the high-purity magnesium oxide fine powder production apparatus of FIG. Is an enlarged view of the peripheral portion of the magnesium vapor nozzle.

In Figure 3, the high purity magnesium oxide fine powder production and recovery apparatus is made of a high-purity magnesium oxide fine powder production apparatus consisting of a metal magnesium melt evaporation apparatus 10 and a magnesium oxidation apparatus 26, a heat exchanger 41, a bug filter as in the case of FIG. A high purity magnesium oxide fine powder recovery device comprising a 42 and a hopper 43 is provided.

Even in the high purity magnesium oxide fine powder production apparatus of FIG. 3, the metal magnesium melt evaporation apparatus 10 includes a lid portion 13 having an inert gas inlet 11 and an oxidation gas inlet 12 for preventing oxidation of the metal magnesium. ) And a metal magnesium melting port 16 consisting of a port portion 15 having a molten magnesium outlet 14 at the lower side of the side, a heat resistant pipe 17 connected to the molten magnesium outlet of the melting port, and the other heat resistant pipe. A port portion 19 having a molten magnesium inlet 18 connected to an end portion at the lower side of the side, and an inert gas inlet 21 for preventing oxidation of the magnesium vapor outlet 20 and the metal magnesium and diluting magnesium vapor. It is comprised by the magnesium evaporation port 23 which consists of the cover part 22 provided with the lid.

Also in the high purity magnesium oxide fine powder production apparatus of FIG. 3, the magnesium oxide oxidizer 26 has a magnesium vapor inlet 27 connected to the magnesium vapor outlet 20 at the bottom of the evaporation port, an oxygen-containing gas inlet 28 at the side, and an upper portion thereof. The fine magnesium oxide fine powder outlet 29 is provided in the In the magnesium oxide device of Fig. 3, the heater 44 is provided at the bottom thereof. As the heater 44, an induction heating type heater and a heating element type heater can be used.

In the magnesium oxidation apparatus of FIG. 3, the magnesium vapor is injected from the magnesium vapor injection port 27 by the oxygen-containing gas injection port 28, and the oxygen-containing gas is brought into contact with the magnesium vapor and the oxygen-containing gas to obtain a high-purity magnesium oxide powder 40. At the same time, the magnesium vapor and the magnesium compound are heated around the magnesium vapor jet port by heating the surroundings of the magnesium vapor jet port 27 to a temperature above the boiling point of the metal magnesium (preferably 1200 to 2000 ° C.) by the heater 44. You can prevent it from sticking well. Therefore, the amount of magnesium vapor introduced into the magnesium oxide device from the magnesium vapor injection port is stabilized for a long time.

In the magnesium oxidation apparatus of FIG. 3, the heater 44 is arranged so as to surround the magnesium vapor injection port as shown in FIG. 4, but the grinding device is arranged around the magnesium vapor injection port 27 of the magnesium oxidation device of FIG. 1. A heater may be provided within a range that does not interfere with the operation of (34), and the grinding of the deposit by the grinding device and the heating around the magnesium vapor injection port by the heater may be performed simultaneously.

According to the method of the present invention, a high purity magnesium oxide fine powder having a narrow width of particle size distribution can be produced continuously over a long period of time.

Claims (11)

A portion of the resulting magnesium oxide fine powder is continuously or intermittently collected while oxidizing magnesium to produce fine magnesium oxide powder by bringing oxygen-containing gas into contact with a mixture of magnesium vapor and inert gas sprayed substantially vertically upwards. And measuring the physical property value related to the particle diameter, and adjusting the flow rate and / or oxygen concentration of the oxygen-containing gas based on the measured physical property value to adjust the particle diameter of the resulting magnesium oxide fine powder to fall within the predetermined particle size range. Method for producing high purity magnesium oxide fine powder. The method for producing a high purity magnesium oxide fine powder according to claim 1, wherein the contact angle between the mixed gas and the oxygen-containing gas is approximately perpendicular to the advancing direction of the mixed gas. The method for producing a high-purity magnesium oxide fine powder according to claim 1 or 2, wherein the physical property value related to the particle diameter is a specific surface. The method for producing a high-purity magnesium oxide fine powder according to any one of claims 1 to 3, comprising the step of adjusting the particle size of the fine magnesium oxide powder produced by adjusting the contacting position of the mixed gas and the oxygen-containing gas. The fine purity magnesium oxide powder manufactured by the manufacturing method in any one of Claims 1-4. A metal magnesium melting port having a metal magnesium inlet at the upper side and a molten magnesium outlet at the lower side thereof, a heat resistant pipe connected to the molten magnesium outlet of the melting port, and a molten magnesium inlet connected to the other end of the heat resistant pipe. A metal magnesium melt evaporation device comprising a magnesium evaporation port provided at the lower side of the side and having a magnesium vapor outlet at the top, a magnesium vapor injection port connected to the magnesium vapor outlet at the bottom of the evaporation port, an oxygen-containing gas injection port at the side, It is composed of a magnesium oxide device having a fine magnesium oxide powder outlet at the top, and the magnesium oxide device has an internal observation window at the side, and removes the metal magnesium or magnesium compound deposited at the magnesium vapor jet in parallel to the bottom thereof. Device laying High purity magnesium oxide fine powder production apparatus, characterized in that. 7. The high purity magnesium oxide fine powder production apparatus according to claim 6, wherein a heater for heating the surroundings of the magnesium vapor injection port is provided at the bottom of the magnesium oxidation apparatus. A metal magnesium melting port having a metal magnesium inlet at the upper side and a molten magnesium outlet at the lower side thereof, a heat resistant pipe connected to the molten magnesium outlet of the melting port, and a molten magnesium inlet connected to the other end of the heat resistant pipe. A metal magnesium melt evaporation device comprising a magnesium evaporation port provided at the lower side of the side and having a magnesium vapor outlet at the top, a magnesium vapor injection port connected to the magnesium vapor outlet at the bottom of the evaporation port, an oxygen-containing gas injection port at the side, A high purity magnesium oxide fine powder production apparatus comprising: a magnesium oxide device having a fine magnesium oxide powder outlet at an upper portion thereof, and a heater for heating the periphery of the magnesium vapor injection hole at the bottom of the magnesium oxide device. A metal magnesium melting port having a metal magnesium inlet at the upper side and a molten magnesium outlet at the lower side thereof, a heat resistant pipe connected to the molten magnesium outlet of the melting port, and a molten magnesium inlet connected to the other end of the heat resistant pipe. It is composed of a magnesium evaporation port provided at the lower side of the side and having a magnesium vapor outlet at the top, and the distance from the molten magnesium inlet to the bottom of the evaporation port is longer than the distance from the molten magnesium outlet of the melting port to the bottom. Metal magnesium melt evaporation apparatus. 10. The apparatus of claim 9, wherein a molten magnesium outlet that is openable at a bottom of the evaporation port is formed. A metal magnesium melting port having a metal magnesium inlet at the upper side and a molten magnesium outlet at the lower side thereof, a heat resistant pipe connected to the molten magnesium outlet of the melting port, and a molten magnesium inlet connected to the other end of the heat resistant pipe. And a magnesium evaporation port provided at a lower side of the side and having a magnesium vapor outlet, and a molten magnesium outlet formed at the bottom of the evaporation port to open and close.