JP5546359B2 - Reduction device and method - Google Patents

Description

  The present invention relates to a reduction apparatus, and more particularly to a reduction apparatus suitable for producing high-purity silicon and reducing carbon dioxide.

Patent Document 1 discloses a hydrogen generation apparatus that efficiently uses renewable energy, recovers reaction energy, and generates hydrogen gas by the present inventors. The hydrogen generator includes a reaction vessel that holds a metal element, a water storage tank for supplying water to the reaction vessel, and a laser that heats the metal element by heating a portion where the metal element contacts the water And a hydrogen extraction pipe for recovering hydrogen gas and reaction energy generated by the reaction between the metal element and the water.
JP 2007-145686 A

  By the way, theoretically, when an oxide such as silicon monoxide or silicon dioxide is subjected to a temperature equal to or higher than the boiling point under a predetermined condition using a laser or the like, silicon and oxygen constituting the silicon dioxide or the like The bond can be ejected while being broken and separated from the heating location. Therefore, in such a case, silicon that can be used as a semiconductor material can be collected.

  Further, for example, when carbon dioxide is heated at a temperature equal to or higher than the boiling point under a predetermined condition using a laser or the like, the carbon and oxygen bonds are ejected while being cut and separated from the heating place. Therefore, in such a case, it should be possible to reduce the amount of carbon dioxide, which is considered to be a cause of global warming.

  However, it is difficult to select "predetermined conditions". In theory, it is very difficult to actually collect high-purity silicon or effectively reduce the amount of carbon dioxide. Have difficulty.

  As a result of research and experiments, the present inventor succeeded in finding the “predetermined condition”. That is, the reduction apparatus of the present invention is based on a mixture or compound of a first oxide (for example, magnesium oxide, potassium oxide or calcium oxide) and a second oxide (for example, carbon dioxide or silicon monoxide). By irradiating a laser, oxygen is removed from the first or second oxide.

  That is, in the present invention, typically, carbon dioxide or silicon monoxide is not simply irradiated with a laser, but is mixed or combined with magnesium oxide, potassium oxide, calcium oxide, or the like. By irradiating with laser, oxygen is removed from carbon dioxide, silicon monoxide, magnesium oxide, potassium oxide or calcium oxide.

More specifically, for example, when magnesium oxide is selected as the first oxide and silicon oxide is selected as the second oxide, and a mixture thereof is prepared, the strength required for the mixture is increased. When this laser is irradiated, Mg, O ₂ , Si and the like are generated, that is, high-purity silicon (Si) can be collected.

  The laser may be a solid-state laser, a gas laser, or a semiconductor laser that uses an energy source including sunlight. In this way, by realizing a laser generated from sunlight or natural energy, a new reduction treatment that is friendly to the global environment is possible without using a power source derived from fossil fuel.

It is a typical block diagram of the laser reduction apparatus of Embodiment 1 of this invention. It is a typical block diagram of the laser reduction apparatus of Embodiment 2 of this invention. It is a typical block diagram of the laser reduction apparatus of Embodiment 3 of this invention. It is a related figure of the mixing ratio of magnesium oxide and silicon monoxide, a magnesium fraction, a silicon fraction [mass%], and energy efficiency [mg / kJ]. It is a typical block diagram of the laser reduction apparatus of Embodiment 4 of this invention. FIG. 2 is a relationship diagram of initial pressure [Pa], magnesium fraction [mass%], and energy efficiency [mg / kJ] in the processing chamber 1 of FIG. It is a relationship figure of the mixing rate of magnesium oxide and silicon monoxide, and the total amount of the acquired spherical high concentration silicon.

DESCRIPTION OF SYMBOLS 1 Processing chamber 2 Incident window 3 Reflecting mirror 4 Adhering medium 5 Container 7 Collection means 9 Lens array

BEST MODE FOR CARRYING OUT THE INVENTION

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, in each figure, the same code | symbol is attached | subjected to the same part.

(Embodiment 1)
FIG. 1 is a schematic configuration diagram of a laser reduction device according to a first embodiment of the present invention. FIG. 1 shows a processing chamber 1 that is also generally referred to as a chamber. An exhaust pump P is attached to the processing chamber 1, and the processing chamber 1 is exhausted as necessary.

  Note that a gas introduction pipe (not shown) is provided in the processing chamber 1, and nitrogen gas, argon gas, helium gas, neon gas, inert gas, or the like can be selectively introduced into the processing chamber 1.

  The processing chamber 1 is provided with a stage 21 on which, for example, a cylindrical container 5 is placed. The container 5 mainly contains, for example, a mixture obtained by stirring magnesium oxide as the first oxide and silicon monoxide as the second oxide.

  In the present embodiment, silicon monoxide is generated by irradiating abundant silicon dioxide on the earth with a laser using the laser reduction device shown in FIG. Therefore, the contents in the container 5 may be, for example, silicon dioxide that is not a mixture of the first oxide and the second oxide. But the acquisition method of the silicon monoxide which is a 2nd oxide is not limited to this.

  Further, the contents in the container 5 can be, for example, magnesium oxide that has adsorbed carbon dioxide, that is, a compound of carbon dioxide and magnesium oxide. Magnesium oxide is known to adsorb carbon dioxide. If magnesium oxide is left in the atmosphere for several days, for example, carbon dioxide in the atmosphere will be adsorbed here. In this embodiment, it is possible to reduce carbon dioxide by irradiating a magnesium oxide adsorbing carbon dioxide with a laser to decompose the carbon dioxide into oxygen and carbon.

  Here, the method for producing silicon monoxide from silicon dioxide will be outlined first. In a container 5, silicon dioxide is accommodated, and a laser irradiation apparatus is used under the condition that the temperature at the position where the spot diameter is formed is 2230 degrees or more (for example, 2500 degrees to 5000 degrees) which is the boiling point of silicon. The laser is irradiated from L.

  As a result, oxygen is separated from silicon dioxide, and silicon monoxide is obtained. In the present embodiment, the silicon monoxide thus obtained is mixed with magnesium oxide or the like as described above and accommodated in the container 5. This mixing ratio is important when silicon or magnesium is efficiently extracted from a mixture of silicon monoxide and magnesium oxide. This point will be described later together with experimental results.

  Further, a motor M that rotates the stage 21 and moves the stage 21 up and down is attached to the stage 21. The rotation of the stage 21 is a process performed to irradiate the laser beam to the contents in the container 5 in a distributed manner.

  The raising / lowering of the stage 21 is a process performed in order to irradiate the things in the container 5 with laser with the same spot diameter. Therefore, it should be noted that it is not always necessary to execute these processes.

  Above the container 5, an adhesion medium 4 to which silicon monoxide, which is an evaporation product of silicon dioxide, is disposed at a predetermined distance S is disposed. In the present embodiment, the evaporated substance is adhered to the adhesion medium 4 by colliding with the adhesion medium 4 in the cooling process.

  In addition, although the adoption example of the plate-shaped adhesion medium 4 is shown in FIG. 1, the adhesion medium 4 of various shapes can be used like other embodiment mentioned later. Further, the adhering medium 4 may be made of any material as long as it satisfies the heat resistance condition that is not dissolved by the heat of the evaporated material adhering thereto. In the present embodiment, a copper plate is used as the adhesion medium 4.

  Furthermore, a hole 22 is formed in the adhesion medium 4 so as not to block the laser irradiated from the laser irradiation device L. In FIG. 1, the formation angle of the hole 22 is set to be parallel to the laser, but the angle is not limited to this as long as the laser reaches the accommodation in the container 5.

  Here, the predetermined distance S is a distance at which the silicon monoxide evaporated from the silicon dioxide in the container 5 can be efficiently attached to the attachment medium 4. As a specific example, when the inside of the processing chamber 1 is set to a vacuum degree of about 6 Pa by the pump P and copper is adopted as the material of the adhesion medium 4, the predetermined distance S can be set to about 5 mm to 15 mm, for example. .

  As a result of an actual experiment, if the predetermined distance S was 25 mm or less, the non-oxygen vapor could be attached to the attachment medium 4. In the case where the predetermined distance S is about 7 mm to about 14 mm, an effect twice or more that of about 5 mm was obtained. Furthermore, when the predetermined distance S is about 8 mm to about 12 mm, the effect of 2.5 times or more of about 5 mm was obtained.

  On the other hand, when the amount of oxygen remaining in the processing chamber 1 is extremely reduced by introducing an inert gas or the like into the processing chamber 1 or reducing the pressure in the processing chamber 1, The inner wall can also be used as an attachment medium. In such a case, the exhausted matter is attached to the periphery of the pump P attached to the processing chamber 1 by the exhaust by the pump P.

  In addition, a known incident window 2 is provided in the upper part of the processing chamber 1 in order to take the laser irradiated from the laser irradiation apparatus L into the processing chamber 1. In addition, a reflecting mirror 3 is provided in the optical path of the laser to change the path of the laser irradiated from the laser irradiation apparatus L toward the incident window 2.

  Note that at least the laser irradiation device L and the reflecting mirror 3 may be connected using an optical fiber (not shown). Similarly, the reflecting mirror 3 and the incident window 2 may be connected to each other by using an optical fiber or the like. If it carries out like this, it will become possible to suppress the optical loss of the laser which arrives at the accommodation thing in the container 5. FIG.

  As the laser irradiation apparatus L, for example, an irradiation apparatus that irradiates a solid laser, a gas laser, or a semiconductor laser of several kW can be used. In various experiments described later, an irradiation apparatus that irradiates a continuous carbon dioxide laser was used.

  Here, the laser irradiation device L may be a solid-state laser, a gas laser, or a semiconductor laser irradiation device that uses an energy source including sunlight. For this type of laser irradiation apparatus, reference is made to PCT / 2009/57671, filed by the inventors, which is not disclosed at the time of this application and is incorporated herein by reference.

  Further, since the kW number of the laser and the spot diameter of the laser determine the temperature given to the contents in the container 5, these selections are important. Specifically, when the laser is 1 kW and the spot diameter is about 2 mm, the temperature at the spot diameter formation position of the contents in the container 5 is about 5000 degrees.

  From this, in order to evaporate the silicon dioxide in the container 5 and to effectively separate silicon monoxide and oxygen, when the laser irradiation apparatus L that irradiates a laser of 1 kW is used, the spot diameter is It may be set to be 2 mm or less.

  Preferably, when the laser irradiation apparatus L of 1 kW is used, if the spot diameter is 2 mm or less, the expansion of silicon dioxide at the laser irradiation position is facilitated, and then silicon monoxide is rapidly cooled. Thus, silicon monoxide can be collected efficiently.

  Further, for example, when a 1 kW laser irradiation apparatus is used to set the spot diameter to 2 mm, silicon dioxide at the laser irradiation position can be expanded to 2 cm, and silicon monoxide is immediately below 100 degrees. Cool to temperature.

  Note that, by keeping the value obtained by dividing the laser kW number by the laser spot area constant, the temperature at the spot diameter formation position of the contents in the container 5 can be made substantially the same. Therefore, for example, when a 4 kW laser is used, the spot diameter may be about 4 mm.

  FIG. 4 is a relationship diagram of the mixing ratio of magnesium oxide and silicon monoxide, magnesium fraction, silicon fraction [mass%], and energy efficiency [mg / kJ]. The horizontal axis of FIG. 4 shows the mixing ratio of magnesium oxide and silicon monoxide, the right vertical axis of FIG. 4 shows magnesium energy efficiency [mg / kJ], and the left vertical axis of FIG. And the silicon fraction [mass%].

  The data shown in FIG. 4 was acquired under the condition that argon gas was introduced into the processing chamber 1 and the inside of the processing chamber 1 was 1 atm. As shown in FIG. 4, it can be seen that as the mixing ratio of silicon monoxide to magnesium oxide increases, the acquisition amount of silicon attached to the copper plate as the attachment medium 4 increases linearly. Therefore, in order to obtain silicon efficiently, it is preferable to increase the mixing ratio of silicon monoxide to magnesium oxide. Although not shown in FIG. 4, even if the mixing ratio of [silicon monoxide / magnesium oxide] is increased to “1: 2” and “1: 3”, a linear increase in silicon acquisition amount can be confirmed. It was.

In addition, high-purity silicon having a substantially spherical shape was obtained on the target 5 side instead of the adhesion medium 4. At this stage, each of these silicon components was analyzed. The analysis results are shown in Table 1.

  As shown in Table 1, all were high-purity silicon of 98% or more, and in each case, only a small amount of oxygen was present. Since other components are below the detection limit, it can be said that they are substantially not contained in high-purity silicon.

  Moreover, as shown in FIG. 4, it turned out that the mixing ratio of magnesium oxide and silicon monoxide also affects the reduction efficiency of magnesium. When magnesium oxide: silicon monoxide = 1: 0.2 to 0.3, the magnesium fraction was about 20% by mass.

  Furthermore, energy efficiency appears to correlate with changes in magnesium reduction efficiency.

  According to the above experimental results, it can be seen that by adjusting the mixing ratio of magnesium oxide and silicon monoxide, the amount of silicon obtained can be increased or decreased, and the reduction efficiency of magnesium can be changed. However, as described above, from the viewpoint of silicon acquisition efficiency, the higher the mixing ratio of silicon monoxide to magnesium oxide, the better. Therefore, the mixing ratio may be determined according to the application. Note that the mixing of silicon monoxide and magnesium oxide may be performed by using a measuring unit of silicon monoxide and magnesium oxide and a mixing unit including a stirrer of silicon monoxide and magnesium oxide.

  FIG. 6 is a relationship diagram among the initial pressure [Pa], the magnesium fraction [mass%], and the energy efficiency [mg / kJ] in the processing chamber 1 of FIG. Focusing on the magnesium fraction in the air atmosphere, it can be seen that the magnesium fraction in the air atmosphere decreases as the initial pressure [Pa] in the processing chamber 1 increases. Next, paying attention to the energy efficiency in the air atmosphere, similarly, it can be seen that the energy efficiency in the air atmosphere decreases as the initial pressure [Pa] in the processing chamber 1 increases.

  On the other hand, in the case of the magnesium fraction in the argon atmosphere, it can be seen that the magnesium fraction in the argon atmosphere increases as the initial pressure [Pa] in the processing chamber 1 increases. In addition, the energy efficiency in the argon atmosphere seems to be less affected by the initial pressure [Pa] in the processing chamber 1.

  According to FIG. 6, it is possible to collect magnesium more effectively in the argon atmosphere treatment than in the air atmosphere, and if the initial pressure in the treatment chamber 1 increases. It can be seen that magnesium can be collected more effectively.

  FIG. 7 is a relationship diagram between the mixing ratio of magnesium oxide and silicon monoxide and the total amount of spherical high-concentration silicon obtained by the target 5. First, as shown in FIG. 7, the high-concentration silicon spheres are exposed on the surface of the mixture of magnesium oxide and silicon monoxide in the container 5, and the approximate diameter is the ratio of magnesium oxide and silicon monoxide. When the ratio is about 1: 1, the diameter increases, and as the ratio increases, the diameter increases. When the ratio of magnesium oxide to silicon monoxide is 1: 3, the diameter is 1 mm. As a result of measuring the purity of the silicon sphere, it was 99% or more.

  As is apparent from FIG. 7, as the mixing ratio of silicon monoxide to magnesium oxide is increased, the total amount of high-concentration silicon is also increased. It can be predicted from FIG. 7 that it is possible to obtain more high-concentration silicon spheres by further increasing the mixing ratio.

(Embodiment 2)
FIG. 2 is a schematic configuration diagram of a laser reduction device according to the second embodiment of the present invention. FIG. 2 shows a comparison with FIG.
(1) The shape of the adhesion medium 4 is changed from a single plate shape to two disk shapes,
(2) The disc-shaped adhering medium 4 can be rotated, and accordingly, a motor M1 connected to the adhering medium 4 is provided.
The laser reduction apparatus which deform | transformed these points is shown.

  When the deposition medium 4 is rotatable, silicon monoxide can be uniformly deposited on the deposition medium 4. The rotation speed of the adhesion medium 4 may be, for example, about 1 rpm to 20 rpm.

(Embodiment 3)
FIG. 3 is a schematic configuration diagram of a laser reduction device according to the third embodiment of the present invention. FIG. 3 shows a comparison with FIG.
(1) A plurality of laser irradiation devices L are provided,
(2) Along with the provision of the plurality of laser irradiation apparatuses L, a lens array 9 for condensing the laser irradiated from each laser irradiation apparatus L onto the accommodation in the container 5 is attached to the processing chamber 1,
(3) Change the adhesion medium 4 to a rotatable cylindrical one,
(4) With the adoption of the cylindrical attachment medium 4, the stage 21 can be moved in the horizontal direction so that the laser beam is irradiated onto the contents in the container 5.
(5) providing a collecting means 7 for collecting evaporate adhering to the adhering medium 4;
The laser reduction apparatus which deform | transformed these points is shown.

  First, by providing a plurality of laser irradiation devices L, it becomes possible to increase the evaporation amount of the contents in the container 5. Therefore, the evaporative collection efficiency of the laser reduction device shown in FIG. 3 is higher than that shown in FIG. For this reason, in this embodiment, in order to increase the adhesion area of the evaporated substance in the adhesion medium 4, the adhesion medium 4 employs a cylindrical shape having a relatively large surface area.

  Further, when the amount of evaporation of the contents in the container 5 increases, the time required for a predetermined amount of the evaporated material to adhere to the adhesion medium 4 is shortened. Therefore, in order to prevent the attachment efficiency of the evaporated material from being lowered, in the present embodiment, the evaporated material attached to the attachment medium 4 is collected by the collection means 7.

  Although the configuration of the collecting means 7 is not limited, as an example, a collecting plate that selectively includes a cooling mechanism that promotes condensation of the evaporated material at intervals of about several mm from the surface of the cylindrical adhesion medium 4. Can be configured by installing. The collection plate may have a sharp end surface. In this way, when the evaporant adheres to the surface of the adherent medium 4 beyond the interval, the evaporate is sharpened from the adherent medium 4 by the collection plate, so that the evaporant can be collected. Become.

(Embodiment 4)
FIG. 5 is a schematic configuration diagram of a laser reduction device according to the fourth embodiment of the present invention. FIG. 5 shows a comparison with FIG.
(1) Install so that the tip of the introduction pipe of inert gas or the like is near the upper surface of the container 5;
(2) The adhering medium 4 composed of a plurality of corrugated plates is disposed on the opposite side of the inlet tube with the container 5 in between.
The laser reduction apparatus which deform | transformed these points is shown.

  When laser is irradiated by the laser irradiation device L while introducing an inert gas or the like from the introduction pipe into the container 5, the evaporated material in the container 5 is deposited on the adhesion medium 4 by the introduced inert gas or the like. The course is changed towards.

  Since the adhering medium 4 is composed of a plurality of corrugated plates, the inert gas or the like itself passes between the plates. At this time, since each plate has a wave shape and is uneven, the evaporated material of the contents in the container 5 collides with the convex portion, and the evaporated material adheres to the adhesion medium 4. Become.

  The structure of the adhesion medium 4 shown in FIG. 5 is merely an example, and a structure such as a diesel filter can also be used. However, in the case of a diesel filter, the inert gas and the evaporant are difficult to pass through, so the structure includes a part where the evaporate collides and a part through which the inert gas passes, like a wavy plate. Is desirable.

  In the present embodiment, the case where a mixture of magnesium oxide and silicon monoxide is mainly treated has been described as an example, but potassium oxide or calcium oxide can be used instead of magnesium oxide. In addition, carbon dioxide can be reduced by using carbon dioxide instead of silicon monoxide.

  The present invention can be used in the field of reduction devices using lasers.

Claims (5)

By irradiating a laser on the mixture or compound of magnesium oxide and silicon monoxide having a ratio of silicon monoxide to 0.1 to 0.4 with respect to magnesium oxide, a reducing device for removal of oxygen from the magnesium oxide . The silicon monoxide, is irradiated with a laser with respect to silicon dioxide, is produced by desorption of oxygen, reduction apparatus according to claim 1. By irradiating a laser on the mixture or compound of magnesium oxide and silicon monoxide having a ratio of silicon monoxide to 0.1 to 0.4 with respect to magnesium oxide, a method for desorption of oxygen from the magnesium oxide. Generating said silicon monoxide by desorption by irradiating oxygen laser against silicon dioxide The method of claim 3. The method of claim 3 , wherein magnesium is collected by treatment in an argon atmosphere.