JP2015137410A - Reducer and reduction method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reducer or the like capable of more efficiently performing reduction of magnesium oxide.SOLUTION: A reducer 1 reduces magnesium oxide for acquiring magnesium. A laser radiation part 200 radiates laser to a magnesium oxide 2 mounted on a stage 120 in a treatment chamber 100. A gas spraying part 300 sprays actuation gas to gas of magnesium evaporated from the magnesium oxide 2 by the radiated laser and to gas of oxygen, in a horizontal direction, for separating gases. The separated magnesium adheres to a collector 400.

Description

  The present invention relates to a reduction device that reduces magnesium oxide to obtain magnesium, and a reduction method.

  There is a technique for obtaining a highly pure metal by reducing the oxide by irradiating the metal oxide with a laser and evaporating it. For example, Patent Document 1 discloses a method of irradiating a metal oxide such as magnesium oxide with a laser while introducing an inert gas into a container, and using the inert gas to evaporate the metal oxide toward a deposition medium. Is disclosed, and a technique for depositing evaporated metal on the deposition medium is disclosed.

JP 2011-255291 A

  However, in Patent Document 1, oxygen and metal are not sufficiently separated in the evaporated product from the metal oxide, and the reduction efficiency is not sufficient.

  This invention is made | formed in view of this problem, Comprising: It aims at providing the reducing apparatus and the reduction | restoration method which can reduce | restore magnesium oxide more efficiently.

In order to achieve the above object, the reduction apparatus of the present invention comprises:
A reduction device for reducing magnesium oxide to obtain magnesium,
A laser irradiation unit for irradiating a magnesium oxide with a laser;
A gas spraying unit that sprays a working gas in a horizontal direction on the magnesium gas evaporated from the magnesium oxide and the oxygen gas by the irradiated laser;
An adhering portion to which the magnesium gas adheres;
It is characterized by providing.

  According to the present invention, it is possible to provide a reduction device and a reduction method that can reduce magnesium oxide more efficiently.

It is a figure which shows schematic structure of the reducing apparatus which concerns on Embodiment 1. FIG. When (a) does not spray working gas, (b) is a figure which shows typically the flow of the vapor | steam which generate | occur | produced by irradiating a laser to magnesium oxide in the case of blowing working gas. It is a figure showing the production | generation efficiency of magnesium with respect to the blowing flow rate of a working gas.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a diagram schematically showing a configuration of a reduction apparatus 1 according to the present embodiment. As shown in FIG. 1, the reduction apparatus 1 includes a processing chamber 100, a laser irradiation unit 200, a gas blowing unit 300, and a collector 400.

  The processing chamber 100 is generally called a chamber and is a place where the magnesium oxide 2 placed in the processing chamber 100 is reduced. An exhaust pump (not shown) is attached in the processing chamber 100, and the processing chamber 100 is evacuated as necessary. In addition, a gas introduction pipe (not shown) is provided in the processing chamber 100, and nitrogen gas, argon gas, helium gas, inert gas, or the like is selectively introduced. In addition, a known incident window 110 is provided in the upper portion of the processing chamber 100 in order to take the laser irradiated from the laser irradiation unit 200 into the processing chamber 100.

  The stage 120 is a table on which the magnesium oxide 2 is placed. The stage 120 may be movable by a driving mechanism (not shown).

  The laser irradiation unit 200 includes a laser irradiation apparatus that irradiates, for example, a solid laser, a gas laser, or a semiconductor laser of several kw. Here, as the laser irradiation unit 200, a solid laser, a gas laser, or a semiconductor laser irradiation apparatus using an energy source including sunlight may be used.

  The path of the laser irradiated from the laser irradiation unit 200 is changed by the reflecting mirror 210 and introduced into the processing chamber 100 through the incident window 110. Note that at least the laser irradiation unit 200 and the reflecting mirror 210 may be connected using an optical fiber (not shown). Similarly, the connection from the reflecting mirror 210 to the entrance window 110 and the connection from the entrance window 110 to the vicinity of the magnesium oxide 2 may be performed using an optical fiber or the like. Thereby, the optical loss of the laser which reaches the magnesium oxide 2 can be suppressed.

  The gas spraying unit 300 is configured by a pipe for introducing the working gas G to the surface of the magnesium oxide 2. The gas blowing unit 300 blows working gas in the horizontal direction against the magnesium gas evaporated from the magnesium oxide 2 and the oxygen gas.

The collector 400, magnesium G _M evaporated from magnesium oxide 2, by impinging in the cooling process, is deposited on the surface. The collector 400 is disposed above the magnesium oxide 2 with a predetermined distance. The collector 400 may be movable with respect to the magnesium oxide 2 by a driving mechanism (not shown). The collector 400 may be made of any material as long as it satisfies the heat resistance condition that is not dissolved by the heat of the evaporate adhering to the surface. For example, a copper plate or a titanium plate can be adopted as the collector 400.

  Next, in the reduction apparatus 1 according to the present embodiment, the speed and flow rate of the working gas ejected by the gas blowing unit 300 will be described.

In general, when an atom of mass m collides with a stationary atom of mass M at a velocity V, if the collision occurs only in a one-dimensional direction, from the conservation of momentum and energy, velocity V _M which atoms are obtained is expressed by equation (1) below.

  Here, since the mass numbers of the magnesium atom and the oxygen atom are 24 and 16, respectively, when the particles of the working gas G collide with the magnesium atom and the oxygen atom, respectively, according to the formula 1, the speed that magnesium obtains is the oxygen Smaller than the speed that the atoms can get. Considering the collision between magnesium and oxygen molecules, the mass numbers are 24 and 32, respectively.

Therefore, in this embodiment, separation of magnesium and oxygen is performed using this difference in speed. FIG. 2A schematically shows a flow of vapor generated by irradiating the magnesium oxide 2 with the laser L when the working gas G is not sprayed and when the working gas G is sprayed in FIG. As shown in FIG. 2 (a), if not blown working gas G, steam G _a of the evaporated magnesium and oxygen from the magnesium oxide 2, regardless of the direction of irradiation of the laser L, perpendicular to the surface of the magnesium oxide 2 Spouts in the direction. Incidentally, when irradiating actually the oxide laser, although steam G _a laterally extending, this divergence is primarily due to thermal velocity with temperature, when a large ejection speed of the vapor G _a, the The spread is negligible.

2B, when the working gas G is sprayed in the horizontal direction, the magnesium vapor G _mg evaporated from the magnesium oxide 2 and the oxygen vapor _Go have different velocities depending on the working gas G. To gain, rise while separating. Here, when the working gas G is blown as shown in FIG. 2B, in a situation where the density is low, the collision between the fluids is small, and the particles pass through each other, each particle is obtained by the collision between the particles. The speed is determined by equation (1). That is, the horizontal velocity V _O obtained by oxygen atoms is different from the velocity V _mg obtained by magnesium atoms. Here, it is assumed that the oxygen mass M 2 _O and the mass m of the working gas G are expressed by the following equation (2).

Further, since the mass ratio of oxygen atoms to magnesium atoms is 16: 24 = 2: 3, the mass M _{mg of} magnesium atoms is expressed by the following formula 3 from this mass ratio and formula 2.

From Equation 1 and Equation 3, the ratio of the velocity V _{o of} oxygen atoms to the velocity V _{mg of} magnesium atoms is expressed by the following Equation 4.

  From the equation (4), it can be seen that as α is larger, that is, as the mass m of the working gas G is smaller, the rate ratio of oxygen and magnesium becomes larger, and it becomes easier to separate oxygen atoms and magnesium atoms. This is supported by FIG. 3, which is an experiment actually performed by changing the working gas. As shown in FIG. 3, the highest reduction efficiency is obtained when helium is used as the working gas compared to argon and nitrogen.

Next, assuming that the kinetic energy involved in the heat of magnesium atoms and oxygen atoms is equal to the heat energy, the heat rate V _tmg [cm / sec] of magnesium and the heat rate V _to of oxygen atoms are expressed as T [K ], Boltzmann constant k = 1.38 × 10 ⁻¹⁶ [erg / K], magnesium atom mass M _mg = 24 × 1.673 × 10 ⁻²⁴ [g], and oxygen atom mass M _o = 16 × 1 .673 × 10 ⁻²⁴ [g] is represented by the following formula 5 and formula 6, respectively.

In Equations 5 and 6, for example, when T = 1000 [K], V _tmg = 5.8 × 10 ⁴ [cm / sec], V _to = 7.2 × 10 ⁴ [cm / sec] Become. Magnesium atoms and oxygen atoms spread in space at thermal speeds of V _tmg and V _to shown by the equations (5) and (6), respectively. Therefore, in order to separate these atoms, the difference in velocity between the oxygen atom velocity V _o and the magnesium atom velocity V _mg is determined by the sum of the magnesium thermal velocity V _tmg and the oxygen atom thermal velocity V _to. Must also grow. That is, it is necessary to satisfy the following equation (7).

Therefore, from the formula 7, the speed V of the working gas G needs to satisfy the following formula 8.

Next, the amount of working gas G to be sprayed will be described. When the radius of oxygen atoms and magnesium atoms is a and the number density of the working gas is n [/ m ³ ], the flight distance L until the oxygen atoms and magnesium atoms collide with the atoms constituting the working gas is as follows: It is expressed by equation (9).

The vertical height of the working gas G blown and H, the magnesium and oxygen ejected by the laser in the height direction of the flow velocity and V _a, the time t it takes for the vapor of the magnesium passes the distance H is less It is expressed by the following equation (10).

Assuming that the injection speed of the working gas G is V, the working gas G travels the flight distance L and collides with the magnesium vapor during the time t.

From the equations (9) to (11), the spray velocity V of the gas to be blown is expressed by the following equation (12).

In Equation 12, if H = 1 [mm], V _a = 10 ⁶ [cm / sec], a is 5 × 10 ⁻⁹ and n = 1 × 10 ¹⁸ by substituting the Bohr radius, V = 1. 3 × 10 ⁵ [cm / sec], which is larger than V _t . The working gas flow rate Q at this time is 1000 [cm ³ / sec] from the following equation (13).

  According to the reducing apparatus 1 configured as described above, magnesium and oxygen evaporated from magnesium oxide can be efficiently separated and high-purity magnesium can be recovered.

  As mentioned above, although embodiment of this invention was described, this invention is not limited by said embodiment.

DESCRIPTION OF SYMBOLS 1 Reduction | restoration apparatus 100 Processing chamber 110 Incident window 120 Stage 200 Laser irradiation part 210 Reflector 300 Gas spraying part 400 Collector

Claims (4)

A reduction device for reducing magnesium oxide to obtain magnesium,
A laser irradiation unit for irradiating a magnesium oxide with a laser;
A gas spraying unit that sprays a working gas in a horizontal direction on the magnesium gas evaporated from the magnesium oxide and the oxygen gas by the irradiated laser;
An adhering portion to which the magnesium gas adheres;
A reduction device. When the mass ratio of oxygen atoms to the mass of the working gas is α, the thermal velocity of magnesium atoms is V _tmg , and the thermal velocity of oxygen atoms is V _to , Spray at a speed of V
The reduction apparatus according to claim 1, wherein:
The gas spraying unit is configured such that the distance from the point where the laser is irradiated to the magnesium oxide to the working gas is H, the velocity in the height direction of the magnesium gas and the oxygen gas is V _a , the magnesium atom, and When the radius of oxygen atoms is a and the number density of the working gas is n, the working gas is blown at a flow rate Q that satisfies the following formula.
The reduction apparatus according to claim 1 or 2, wherein
A reduction method for obtaining magnesium by reducing magnesium oxide,
A laser irradiation step of irradiating the magnesium oxide with a laser;
A gas spraying step of spraying a working gas in a horizontal direction to the magnesium gas evaporated from the magnesium oxide and the oxygen gas by the irradiated laser;
An attaching step of attaching the magnesium gas to the attaching portion;
A reduction method comprising: