JP7303239B2 - Burner for producing inorganic spherical particles, method for producing inorganic spherical particles, and inorganic spherical particles - Google Patents

Description

TECHNICAL FIELD The present invention relates to a burner for producing spherical inorganic particles, a method for producing spherical inorganic particles, and spherical inorganic particles.

Conventionally, as a method for producing inorganic spherical particles, for example, a so-called flame melting method has been adopted, in which inorganic raw material powder is passed through a flame to melt the surface and form spherical particles.
When the inorganic spherical particles are produced by such a method, the particle size of the inorganic spherical particles to be the product particles depends on the particle size of the raw material powder, and the product particles having a particle size approximately close to that of the raw material powder are produced. be.
In addition, since a high-temperature flame is required to spheroidize the raw material powder in a flame, an oxygen/gas fuel burner is usually used in the flame fusion method (for example, Patent Document 1 ).

FIG. 1 shows an example of a system diagram of an apparatus 100 for producing spherical inorganic particles, which has been conventionally generally used and which is equipped with a burner for producing spherical inorganic particles.
In the system diagram shown in FIG. 1 , raw material powder (not shown) is cut out from a powder feeder 102 , accompanied by a carrier gas supplied from a path 101 , and transported to an oxygen/gas combustion burner 200 . Oxygen supplied from the oxygen supply equipment 105 and fuel gas supplied from the fuel supply equipment 104 are introduced into the oxygen/gas combustion burner 200, and the raw material powder is spheroidized in the flame in the furnace 106. to produce inorganic spheroidized particles. After that, the inorganic spherical particles are conveyed and temperature-diluted by the air introduced into the furnace 106 from the path 107 and recovered by the cyclone 108 and the bag filter 109 in the latter stage.

The cross-sectional view of FIG. 2 shows a schematic structure of a diffusion burner used in the oxygen/gas combustion burner 200 described above.
As shown in FIG. 2, a raw material supply passage 201 for supplying raw material powder and carrier gas is provided at the central portion along the central axis of the oxygen/gas combustion burner 200, and fuel gas is supplied to the outer peripheral side thereof. A fuel supply passage 202 is provided for the fuel supply, and an oxygen gas supply passage 203 for supplying oxygen, which is a combustion-supporting gas, is provided on the outer peripheral side. With such a configuration, the fuel gas and oxygen are mixed in the combustion chamber 204 on the tip side to form a flame. In addition, the oxygen gas supply passage 203 consists of a first oxygen gas supply passage 205 for forming a swirling flow in the combustion chamber 204 and a second oxygen gas supply passage 206 for ejecting oxygen gas in the axial direction. Equipped with a supply channel.
The inorganic spherical particle manufacturing apparatus 100 equipped with the oxygen/gas combustion burner 200 spheroidizes the inorganic raw material powder by the flame fusion method to manufacture inorganic spherical particles.

JP-A-7-48118

In recent years, in the market for spheroidized products, there has been an increasing demand for improved quality of these spheroidized products, and a higher degree of spheroidization has been demanded.

The present invention has been made in view of the above-mentioned problems, and it is possible to manufacture inorganic spheroidal particles having an excellent degree of spheroidization without increasing the number of production facilities and increasing the costs associated therewith. It is an object of the present invention to provide a burner for industrial use, a method for producing inorganic spherical particles, and inorganic spherical particles.

In order to solve the above problems, the present invention includes the following aspects.
That is, the invention according to claim 1 is a burner for producing inorganic spherical particles, which has a bottomed cone-shaped combustion chamber that is open so that the tip side in the flame forming direction is enlarged in diameter, wherein toward the combustion chamber, a raw material powder supply passage for supplying raw material powder using oxygen or oxygen-enriched air as a carrier gas; a fuel gas supply path; and an oxygen gas supply path arranged to surround the fuel gas supply path from the outer peripheral side and supplying oxygen gas toward the combustion chamber, wherein the raw material powder supply path A plurality of raw material powder supply ports provided in a powder distribution plate disposed at the bottom of the combustion chamber are opened into the combustion chamber, and the plurality of raw material powder supply ports are used for the production of the inorganic spherical particles. The fuel gas supply path is arranged so as to surround the central axis of the burner for combustion, and the fuel gas supply path is provided in a plurality so as to open to the side wall of the combustion chamber and surround the raw material powder supply port in plan view, It has a fuel gas ejection port for ejecting the fuel gas in a direction along the central axis, and the oxygen gas supply path opens in the side wall of the combustion chamber and surrounds the fuel gas ejection port in a plan view. and a plurality of first oxygen gas ejection ports for ejecting the oxygen gas while forming a swirling flow in a plane perpendicular to the central axis; and the first oxygen gas ejection ports on the sidewall of the combustion chamber. a plurality of second oxygen gas ejection ports which open at a position downstream of the second oxygen gas ejection port and are provided so as to surround the first oxygen gas ejection port in a plan view, and eject the oxygen gas toward the central axis; The momentum of the fuel gas ejected from the fuel gas ejection port is _mf , and the momentum of the oxygen gas ejected from the second oxygen gas ejection port _m0 in the tangential direction to the central axis is m ₀ and θ, the burner for producing spherical inorganic particles is characterized by satisfying the relationship represented by the following formula (1).
m _f /m ₀ , θ ≤ 1.0 (1)

Further, the invention according to claim 2 is the burner for producing spherical inorganic particles according to claim 1, wherein the jet speed of the fuel gas jetted from the fuel gas jet port is 50 m/s or less. It is a burner for producing inorganic spherical particles.

Further, the invention according to claim 3 is the burner for producing spherical inorganic particles according to claim 1 or claim 2, wherein the raw material powder ejected from the raw material powder supply port is supplied to the combustion chamber. This burner for producing spherical inorganic particles is characterized by jetting at an angle that radially widens toward the downstream side.

According to a fourth aspect of the present invention, there is provided a burner for producing spherical inorganic particles according to the third aspect, wherein the raw material powder ejected from the raw material powder supply port has an ejection angle α of 0 with respect to the central axis. A burner for producing inorganic spheroidized particles characterized in that the angle is ~15°.

Further, the invention according to claim 5 is the burner for producing spherical inorganic particles according to any one of claims 1 to 4, wherein the fuel gas is a gas containing no carbon. It is a burner for producing inorganic spherical particles.

The invention according to claim 6 is the burner for producing spherical inorganic particles according to claim 5, wherein the fuel gas is ammonia or hydrogen. .

Further, the invention according to claim 7 is the inorganic spherical particle production burner according to any one of claims 1 to 6, wherein a cooling water is provided outside the combustion chamber. A burner for producing inorganic spherical particles, characterized by having a cooling water conduit.

The invention according to claim 8 is a method for producing spherical inorganic particles, characterized by using the burner for producing inorganic spherical particles according to any one of claims 1 to 7.

Further, the invention according to claim 9 is obtained by the burner for producing inorganic spherical particles according to any one of claims 1 to 7 or the method for producing spherical inorganic particles according to claim 8. It is an inorganic spherical particle characterized by being

According to the burner for producing spherical inorganic particles according to the present invention, as described above, the momentum of the fuel gas ejected from the fuel gas ejection port is _mf , and the momentum of the oxygen gas ejected from the second oxygen gas ejection port is m When the momentum of ₀ in the tangential direction to the central axis is m ₀ , θ, the relationship between them satisfies the following equation [m _f /m ₀ , θ≦1.0].
In this way, the momentum [m _f ] of the fuel gas ejected from the fuel gas ejection port and the momentum [m ₀ ] of the oxygen gas ejected from the second oxygen gas ejection port in the tangential direction with respect to the central axis [m ₀ , .theta.] in the optimum range, the mixing property of the fuel gas and the oxygen gas is improved, and the maximum temperature of the formed flame is increased. As a result, since the amount of heat transferred to the raw material powder is increased, the degree of vitrification of the inorganic spherical particles is increased, and the raw material powder can be efficiently melted and sphericalized. The degree of spheroidization is also enhanced.
Therefore, it is possible to produce inorganic spheroidized particles having an excellent degree of spheroidization without increasing the number of production facilities and increasing the costs associated therewith.

In addition, according to the method for producing spherical inorganic particles according to the present invention, since it is a method for producing spherical inorganic particles using the burner for producing spherical inorganic particles according to the present invention having the above configuration, the formation is similar to that described above. Since the maximum temperature of the flame is increased, the amount of heat transferred to the raw material powder is also increased, so that the degree of vitrification of the inorganic spherical particles is increased, and the raw material powder can be efficiently melted and spheroidized. As a result, the degree of spheroidization of the inorganic spheroidized particles is also increased.
Therefore, it is possible to produce inorganic spherical particles having an excellent degree of spheroidization without increasing the number of production facilities and increasing costs associated therewith.

Further, according to the inorganic spherical particles of the present invention, the inorganic spherical particles are obtained by using the burner for producing the inorganic spherical particles of the present invention having the above configuration or the method of producing the inorganic spherical particles. , which is inexpensive and excellent in the degree of spheroidization.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a system diagram for explaining the schematic configuration of an inorganic spherical particle manufacturing apparatus generally used for manufacturing inorganic spherical particles. FIG. 2 is a cross-sectional view for explaining an example of the introduction/ejection form of each gas to a burner for producing inorganic spherical particles generally used for producing spherical inorganic particles. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram schematically illustrating a burner for producing spherical inorganic particles, which is an embodiment of the present invention, and is a plan view of the burner viewed along the central axis from the flame ejection side. FIG. 4 is a diagram schematically illustrating a burner for producing inorganic spherical particles, which is an embodiment of the present invention, and is a cross-sectional view of the burner shown in FIG. 3 taken along the line AA. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view for explaining an embodiment of a burner for producing spherical inorganic particles and a method for producing spherical inorganic particles according to the present invention, and the miscibility of fuel gas and oxygen gas represented by the following formula [mf/m0, θ] and the vitrification degree (%) of the obtained inorganic spherical particles.

Hereinafter, a burner for producing spherical inorganic particles, a method for producing spherical inorganic particles, and spherical inorganic particles obtained thereby, which are embodiments of the present invention, will be described with reference to the accompanying drawings. In addition, in the drawings used in the following explanation, in order to make the features easier to understand, the characteristic portions may be enlarged for convenience, and the dimensional ratios of each component may not necessarily be the same as the actual ones. do not have. Also, the materials and the like exemplified in the following description are merely examples, and the present invention is not limited to them, and can be implemented with appropriate modifications within the scope of the invention.

<Inorganic spherical particles>
The spherical inorganic particles of the present embodiment are produced by the burner for producing spherical inorganic particles and the method of producing spherical inorganic particles of the present embodiment, the details of which will be described later.
The inorganic spherical particles of the present embodiment can be obtained by using raw material powders such as silica, alumina, magnetite, or glass raw material powder, and using the burner for producing inorganic spherical particles and the method for producing inorganic spherical particles of the present embodiment. It is obtained by spheroidizing by the flame melting method used.
The inorganic spherical particles of this embodiment have a very high degree of spheroidization, for example, 85 to 98%. The degree of spheroidization described in the present embodiment means a value obtained by dividing the short diameter of the particles after the melting treatment by the long diameter. Such a degree of spheroidization is measured, for example, using a scanning electron microscope at a measurement magnification at which the number of inorganic spherical particles contained in one field of view is about 100 to 200, and the number-based arithmetic mean value is calculated. Just calculate.

<Burner for producing inorganic spherical particles>
3 and 4, a burner 1 for producing spherical inorganic particles (hereinafter sometimes simply referred to as burner 1), which is an embodiment of the present invention, will be described below.
FIG. 3 is a plan view of the burner 1 of the present embodiment, viewed along the central axis J from the flame ejection side (not shown), and FIG. 4 is a cross-sectional view taken along the line AA shown in FIG. . In FIG. 4, since it is difficult to show the entire burner 1 extending in a predetermined direction, only the tip portion of the burner 1 is shown. Also, in FIG. 4, only the tip portion of the burner 1 is shown as a cross-sectional view for convenience of explanation. Furthermore, in the plan view of FIG. 3, the first oxygen gas ejection port 51 (first oxygen gas supply passage 5A) does not overlap the position of the AA section line. In the -A sectional view, the first oxygen gas ejection port 51 and the first oxygen gas supply passage 5A are also shown.

The burner 1 of the present embodiment is provided, for example, in an inorganic spherical particle manufacturing apparatus 100 as shown in FIG. 1 for the purpose of manufacturing inorganic spherical particles by melting and spheroidizing raw material powder. .

As shown in FIGS. 3 and 4, the burner 1 of this embodiment has a conical combustion chamber 2 with a bottom that opens so that the diameter of the tip 1A side in the direction of flame formation increases. In the burner 1 of the present embodiment, the raw material powder contained in the raw material fluid G1 is exposed to a high-temperature atmosphere caused by a flame in the combustion chamber 2, and the water droplets in the raw material fluid G1 are evaporated to increase the sphericity. In this method, inorganic spheroidized particles composed of fine particles are produced.
The raw material fluid G1 described in the present embodiment refers to the entire fluid containing raw material powder using oxygen or oxygen-enriched air as a carrier gas.

As shown in the cross-sectional view of FIG. 4, the burner 1 has a raw material powder supply path 3 for supplying a raw material fluid G1 containing raw material powder on the central axis J. A fuel gas supply path 4 for supplying fuel gas G2 into the combustion chamber 2 is arranged so as to surround the raw material powder supply path 3 . Further, on the outer peripheral side thereof, an oxygen gas supply passage 5 is arranged so as to surround the fuel gas supply passage 4 and supplies oxygen gas into the combustion chamber 2. In the illustrated example, a first oxygen gas supply passage 5 is arranged. The two systems of oxygen gas supply paths, ie, the gas supply path 5A and the second oxygen gas supply path 5B, are arranged concentrically in the order of the first oxygen gas supply path 5A and the second oxygen gas supply path 5B from the center axis J side. It is

The raw material powder supply path 3 is opened into the combustion chamber 2 by a plurality of raw material powder supply ports 31 provided in a powder distribution plate 30 disposed at the bottom of the combustion chamber 2, and passes through a plurality of raw material powders. The body supply port 31 is arranged so as to surround the central axis J of the burner 1 for producing spherical inorganic particles.
The fuel gas supply passages 4 are provided in a plurality so as to open to the side wall 22 of the combustion chamber 2 and surround the raw material powder supply port 31 in a plan view (see FIG. 3). It has a fuel gas ejection port 41 for ejecting gas G2.

Further, the first oxygen gas supply passage 5A in the illustrated example opens to the side wall 22 of the combustion chamber 2, and is provided in plurality so as to surround the fuel gas ejection port 41 in plan view (see FIG. 3). It has a first oxygen gas ejection port 51 that ejects the oxygen gas G3 while forming a swirling flow in a plane perpendicular to the . Furthermore, the second oxygen gas supply passage 5B in the illustrated example opens at a position downstream of the first oxygen gas jet port 51 in the side wall 22 of the combustion chamber 2, and surrounds the first oxygen gas jet port 51 in plan view. , and has second oxygen gas ejection ports 52 for ejecting oxygen gas G4 toward the central axis J. As shown in FIG.

In the burner 1 of the present embodiment, the momentum of the fuel gas G2 ejected from the fuel gas ejection port 41 is defined as _mf , and the momentum _m0 of the oxygen gas G4 ejected from the second oxygen gas ejection port 52 is defined by the central axis J When the momentum in the tangential direction to is m ₀ , θ, these relationships satisfy the relationship represented by the following formula [m _f /m ₀ , θ≦1.0].

As shown in FIGS. 3 and 4, the combustion chamber 2 is a concavity with a bottom that opens so that the diameter of the tip 1A increases. In FIG. cone shape). In addition, in the illustrated combustion chamber 2, a powder distribution plate 30 provided with a plurality of raw material powder supply ports 31 is arranged as a bottom portion of a concavity with a bottom.
As described above, the burner 1 of the present embodiment synthesizes fine particles from raw material powder by evaporating water droplets in the raw material fluid G1 in a high-temperature atmosphere caused by flames in the combustion chamber 2 .

The combustion chamber 2 may have a constant inclination angle α of the side wall 22 from the base end side bottom to the tip 1A side of the burner 1. However, as shown in FIG. From the viewpoint of ensuring stable flame stabilization, it is more preferable that the is cylindrical.

The raw material powder supply path 3 is arranged on the central axis J of the burner 1 .
The raw material powder supply port 31, which is the opening of the raw material powder supply path 3, is opened to the powder dispersion plate 30 arranged at the bottom of the combustion chamber 2 as described above, and is shown in FIG. In the example, they are provided at a total of eight locations so as to surround the central axis J and are arranged at equal intervals on the circumference.
The raw material powder supply port 31 is provided with a plurality of openings so as to eject the raw material fluid G1 containing the raw material powder and fuel supplied from the raw material powder supply passage 3 toward the inside of the combustion chamber 2, as shown in FIG. In the example shown in FIG.

In this embodiment, as shown in the drawing, a plurality of raw material powder supply ports 31 are communicated with the raw material powder supply path 3, and the raw material fluid G1 is ejected from the plurality of raw material powder supply ports 31. However, the configuration is not limited to this. For example, the raw material powder supply port 31 may be configured as a single hole.

The material of the powder dispersion plate 30 in which the plurality of raw material powder supply ports 31 are formed is not particularly limited, but in order to suppress the occurrence of wear, a metal material coated with a wear-resistant material, or It is preferable to employ a ceramic material such as alumina or silicon carbide.

Further, the raw material fluid G1 containing the raw material powder ejected from the raw material powder supply ports 31 is ejected at an angle that radially widens toward the downstream side of the combustion chamber 2. is preferred. More specifically, the ejection angle α of the raw material fluid G1 ejected from the raw material powder supply port 31 with respect to the central axis J can be arbitrarily set. It is more preferable from the viewpoint that the inorganic spherical particles can be uniformly diffused in the combustion chamber 2, heat-melting efficiency is improved, and the degree of spheroidization is enhanced.

A plurality of fuel gas supply passages 4 are arranged in parallel outside the raw material powder supply passage 3 arranged on the central axis J so as to surround the raw material powder supply passage 3 .
A fuel gas outlet 41, which is an opening of the fuel gas supply path 4, is formed on the side wall 22 of the combustion chamber 2 in a plan view (see FIG. 3) so as to correspond to the arrangement position of the fuel gas supply path 4. A plurality of them are provided so as to surround the body supply port 31, and in the illustrated example, there are a total of eight locations, which are provided so as to be arranged at equal intervals on the circumference.

A plurality of first oxygen gas supply paths 5A are arranged in parallel so as to surround the fuel gas supply path 4 from the outer peripheral side.
A first oxygen gas ejection port 51, which is an opening of the first oxygen gas supply passage 5A, is formed on the side wall 22 of the combustion chamber 2 in a plan view (Fig. 3) are provided in a plurality so as to surround the fuel gas ejection port 41, and in the illustrated example, there are a total of eight locations, which are provided so as to be arranged at equal intervals on the circumference. In addition, the first oxygen gas ejection port 51 is opened in the side wall 22 of the combustion chamber 2 so as to eject the oxygen gas G3, which becomes the primary oxygen, while forming a swirling flow within a plane perpendicular to the central axis J. ing. That is, the first oxygen gas ejection port 51 is provided so as to open in a direction orthogonal to the central axis J in the side wall 22 of the combustion chamber 2, as shown in FIG.

In addition, if the first oxygen gas ejection port 51 is opened in the side wall 22 of the combustion chamber 2 at such a position as to form a swirling flow of the oxygen gas G3 with respect to the central axis J, the raw material powder supply port 31 Also, the distance from the fuel gas ejection port 41, the number of holes, the shape, etc. are not particularly limited, and can be arbitrarily set according to the desired properties of the flame.

As described above, the second oxygen gas supply paths 5B are arranged in parallel on the outer peripheral side of the plurality of first oxygen gas supply paths 5A so as to surround the first oxygen gas supply paths 5A.
The second oxygen gas ejection port 52, which is the opening of the second oxygen gas supply path 5B, is the first oxygen gas ejection port on the side wall 22 of the combustion chamber 2 corresponding to the arrangement position of the second oxygen gas supply path 5B. At a position on the tip 1A side of the outlet 51, a plurality of outlets are provided so as to surround the raw material powder supply port 31, the fuel gas ejection port 41, and the first oxygen gas ejection port 51 in a plan view. , are provided so as to be arranged at equal intervals on the circumference. Further, the second oxygen gas jetting port 52 is opened in the side wall 22 of the combustion chamber 2 toward the central axis J so as to jet out the oxygen gas G4 that becomes secondary oxygen.

Similarly to the first oxygen gas ejection port 51 described above, the second oxygen gas ejection port 52 is located on the side wall 22 of the combustion chamber 2 on the tip 1A side of the first oxygen gas ejection port 51, and If the opening is at a position where the oxygen gas G4 is ejected toward J, the distance from the raw material powder supply port 31, the fuel gas ejection port 41, and the plurality of first oxygen gas ejection ports 51, the number of holes, and the shape etc. are not particularly limited, and can be arbitrarily set according to the desired properties of the flame.

In this embodiment, a total of two oxygen gas supply paths 5, a first oxygen gas supply path 5A and a second oxygen gas supply path 5B, are provided. Although the configuration in which the ejection port 52 is provided has been described, the configuration is not limited to this. For example, by providing only one system of the oxygen gas supply channel 5 and providing a branch channel in the oxygen gas supply channel 5, the first oxygen gas ejection port 51 and the second oxygen gas ejection port 51 are provided from the one system of the oxygen gas supply channel 5. A configuration in which oxygen gas is supplied to both outlets 52 may be employed.

Further, the burner 1 of the example shown in FIG. The cooling water pipe 6 is arranged so that the tip 61 is adjacent to the combustion chamber 2 . Further, the cooling water pipe 6 of the illustrated example is configured such that two flow paths 6a and 6b are connected so as to be folded back at the tip 61, and the two flow paths extend from the rear end side of the burner 1. The cooling water W supplied to either one of 6a and 6b is turned back at the front end 61 and returned to the rear end side from the other flow path.

The number and positions of the cooling water pipes 6 are not particularly limited, and a plurality of them may be arranged like the first oxygen gas supply channel 5A and the second oxygen gas supply channel 5B. It may be formed in an annular shape over the entire circumference of the burner 1 in plan view.

In this embodiment, the cooling water pipe 6 is provided outside the combustion chamber 2 to protect each component of the burner 1 from the high temperature atmosphere and radiant heat caused by the flame, and to prevent excessive heating in the combustion chamber 2. is suppressed, and it becomes possible to synthesize inorganic spherical particles while controlling the combustion field more uniformly.

As described above, in the burner 1 of the present embodiment, the momentum of the fuel gas G2 ejected from the fuel gas ejection port 41 is _mf , and the momentum _m0 of the oxygen gas G4 ejected from the second oxygen gas ejection port 52 is: When the momentum in the tangential direction to the central axis J is m ₀ , θ, these relationships satisfy the relationship represented by the following equation (1) (see also FIG. 4).
m _f /m ₀ , θ ≤ 1.0 (1)

Below, the definition of the ratio of each momentum represented by the above formula (1) will be described in detail.
FIG. 4 shows the momentum m 0 , θ in the tangential direction to the central _axis J when the momentum m _f of the fuel gas G2 and the momentum m ₀ of the oxygen gas G4, which is secondary oxygen, are decomposed into elements. there is
In addition, the graph of FIG. 5 shows the index (-) related to the miscibility of the fuel gas G2 and the oxygen gas G4 represented by the above equation (1), and the degree of vitrification of the inorganic spherical particles recovered by the cyclone. (%), and shows the case where ammonia is used as the fuel gas G2.
Each momentum (kg·m/s) is calculated by the following formula [nozzle jet flow velocity (m/s)×mass of gas derived from gas jet volume (kg)].
Further, the momentum m ₀ , θ of the secondary oxygen in the tangential direction with respect to the central axis J is calculated by the following formula [m ₀ ×sin θ]. Here, θ in the above formula is the angle formed by the central axis J and the _m0 vector.

As shown in the graph of FIG. 5, when the value of [m _f /m ₀ , θ] is 1.0 or less, the degree of vitrification tends to increase rapidly. Furthermore, when the value of [m _f /m ₀ , θ] is 0.48 or less, the degree of vitrification is about 90%, and the value of [m _f /m ₀ , θ] is in the range of 0.29 to 048. It can be seen that it becomes even better with
Therefore, the value of [m _f /m ₀ , θ] in the above formula (1) is preferably 1.0 or less, more preferably 0.50 or less, and is in the range of 0.29 to 048. More preferred.

As described above, the value of [m _f /m ₀ , θ] in the above formula (1) is an index indicating the miscibility between the fuel gas G2 and the oxygen gas G4, which is secondary oxygen. The smaller the value, the better the miscibility between the gases, while the greater the value, the lower the miscibility. That is, by properly mixing the fuel gas G2 and the oxygen gas G4, the maximum temperature of the flame formed in the combustion chamber 2 rises, and the heat transfer to the raw material fluid G1 containing the raw material powder becomes advantageous. , it becomes possible to improve the vitrification degree of the resulting inorganic spherical particles. That is, by producing inorganic spherical particles using the burner 1 of the present embodiment, inorganic spherical particles excellent in the degree of spheroidization can be efficiently obtained.

Furthermore, in the present embodiment, even when a fuel gas such as ammonia that does not contain carbon and has a low brightness is used as the fuel gas G2, the raw material powder contained in the raw material fluid G1 can be efficiently melted and sphericalized. It is possible to produce inorganic spheroidized particles having an excellent degree of spheroidization while suppressing the carbon content, which may cause troubles during use of the product. Such effects can be achieved by efficient melting and spheroidization even when materials other than silica, such as alumina, magnetite, and glass, are used as raw material powders made of inorganic materials. It suggests that there is

The ejection speed of the fuel gas G2 ejected from the fuel gas ejection port 41 is not particularly limited, but is preferably 50 m/s or less, for example. When the ejection speed of the fuel gas G2 is 50 m/s or less, the raw material powder stays in the flame for a long time, and heat is sufficiently transferred to the raw material powder, so that the degree of fusion is further improved. . The lower limit of the ejection speed of the fuel gas G2 is also not particularly limited, but from the viewpoint of manufacturing the nozzle (ejection port), the diameter of the fuel gas ejection port 41 can be designed with an appropriate size, so it is preferable to be 10 m / s or more. preferable.

Further, as a result of intensive studies by the present inventors, it has been found that in a diffusion burner such as the burner 1 of the present embodiment, a common carbon-based fuel such as liquefied propane gas (LPG) or natural gas is used as the fuel gas G2. It has been clarified that, when used, the raw material powder can be spheroidized more efficiently by suppressing the ejection speed of the fuel gas G2 to 50 m/s or less.

Therefore, the ejection speed of the fuel gas G2 ejected from the fuel gas ejection port 41 is preferably in the range of 10 to 50 m/s regardless of the gas type.

The ejection speed of the oxygen gas G4, which is secondary oxygen, ejected from the second oxygen gas ejection port 52 is also not particularly limited, but is preferably in the range of 60 to 120 m/s, for example.
When the ejection speed of the oxygen gas G4 is 60 m/s or more, the raw material powder contained in the raw material fluid G1 and the fuel gas G2 are sufficiently mixed, so that the degree of fusion is further improved.
In addition, since the jet speed of the oxygen gas G4 is 120 m/s or less, the size of the flame formed is increased, so that the raw material powder stays in the flame for a long time, and the raw material powder Since heat is transmitted to the , the degree of fusion is further improved.

The ejection speed of the oxygen gas G3, which is the primary oxygen, ejected from the first oxygen gas ejection port 51 is also not particularly limited, but from the viewpoint of improving the degree of fusion, it is preferably in the range of, for example, 50 to 100 m/s. .
By setting the ejection speed of the oxygen gas G3 ejected from the first oxygen gas ejection port 51 to be 50 m/s or more, the fuel and oxygen are sufficiently mixed, and the effect of suppressing the generation of unburned matter can be obtained. be done.
Further, when the jet speed of the oxygen gas G3 jetted from the first oxygen gas jet port 51 is 100 m/s or less, the size of the flame that is formed is increased. Since it becomes longer and heat is sufficiently conducted to the raw material powder, the degree of fusion is further improved.

The ejection speed of the oxygen or oxygen-enriched air used as the carrier gas for the raw material powder from the raw material powder supply port 31, that is, the ejection speed of the raw material fluid G1 is also not particularly limited, but it depends on the degree of melting of the raw material powder. From the viewpoint of improving, for example, it is preferably in the range of 20 to 60 m/s.
When the ejection speed of the raw material fluid G1 ejected from the raw material powder supply port 31 is 20 m/s or more, it is possible to obtain the effect of preventing the raw material from sticking in the vicinity of the nozzle.
In addition, since the ejection speed of the raw material fluid G1 ejected from the raw material powder supply port 31 is 60 m/s or less, the raw material powder stays in the flame for a long time, and the raw material powder is sufficiently heated. Since heat is transmitted, the degree of fusion is further improved.

In the burner 1 of this embodiment, it is more preferable to use a carbon-free gas as the fuel gas G2. Specifically, it is more preferable to use a carbon-free fuel such as ammonia or hydrogen as the fuel gas G2.
By using a carbon-free fuel as the fuel gas G2 in this manner, the amount of carbon taken into the inorganic spherical particles during the process of melting and sphericalizing the raw material powder in the flame can be suppressed.

As described above, in the spheroidized product market, the demand for improving the quality of this spheroidized product is increasing year by year. As an example, for spherical silica used as a sealant for semiconductors, in addition to improving the degree of spheroidization as described above, electrical shorts that occur on the semiconductor substrate may cause operational problems. It is strongly desired to reduce the content of carbon, which is an impurity.

When producing spherical silica by the flame fusion method, for example, if a carbon-based fuel such as liquefied propane gas (LPG) or natural gas is used as the fuel gas, a trace amount of carbon derived from the composition of the fuel gas is mixed into the product. There is a problem that Therefore, in order to eliminate carbon impurities, it is conceivable to spheroidize the raw material powder using a carbon-free fuel gas such as ammonia or hydrogen.

On the other hand, carbon-free fuel gases, such as ammonia and hydrogen, are characterized by extremely low flame brightness compared to conventionally used carbon-based fuels. This flame brightness has a great influence on the degree of spheroidization of the raw material powder in spheroidization using the flame fusion method. Therefore, when ammonia or hydrogen is used as the fuel gas in conventional manufacturing equipment, the degree of spheroidization of the raw material powder is reduced with a diffusion burner designed similarly to the conventional carbon-based fuel, and sufficient quality products can be obtained. There is also the aspect of being hard to get.

However, according to the burner 1 of the present embodiment, as described above, the momentum of the fuel gas G2 ejected from the fuel gas ejection port 41 is _mf , and the momentum of the oxygen gas G4 ejected from the second oxygen gas ejection port 52 is When the momentum of m ₀ in the tangential direction to the central axis J is m ₀ , θ, a configuration is adopted in which these relationships satisfy the relationship represented by the following formula [m _f /m ₀ , θ ≤ 1.0] are doing. As a result, even if a carbon-free fuel gas with a low flame brightness is used, the raw material powder can be efficiently heated and melted to be spheroidized.

In this embodiment, the same oxygen gas may be used as the oxygen gas G3, which is primary oxygen, and the oxygen gas G4, which is secondary oxygen, or different types of combustion-supporting gases may be used. It is possible. In this case, for example, oxygen-enriched air or the like can be appropriately employed as the combustion-supporting gas other than oxygen.

[Method for Producing Inorganic Spherical Particles]
The method for producing spherical inorganic particles of the present embodiment is a method of producing spherical inorganic particles using the burner 1 of the present embodiment configured as described above.
That is, in the manufacturing method of the present embodiment, first, a raw material powder made of silica, alumina, magnetite, glass, or the like is mixed with a carrier gas to prepare a raw material fluid G1, which is jetted into the combustion chamber 2.
In the combustion chamber 2, the fuel gas G2 and the oxygen gases G3 and G4 are burned to form a flame, and the raw material powder contained in the raw material fluid G1 is allowed to stay in the flame, thereby melting the raw material powder. - A method of producing spherical inorganic particles by spheroidizing to form fine particles.

As an apparatus for producing inorganic spherical particles by the above-described method, for example, in addition to the burner 1 of the present embodiment, an inorganic spherical particle producing apparatus 100, which has been generally used conventionally, shown in FIG. As provided, a powder feeder 102 for supplying the raw material powder to form the raw material fluid G1, a fuel supply facility 104 for supplying the fuel gas G2, and for supplying the oxygen gases G3 and G4 An oxygen supply facility 105, a furnace 106, a cyclone 108, a bag filter 109, etc., as well as a carrier gas supply means, a flow controller for adjusting the flow rate of each fluid, and the like can be used.

Specifically, in the production method of the present embodiment, first, in the powder feeder 102, the raw material powder is mixed with a carrier gas made of oxygen or oxygen-enriched air, and the raw material powder is dispersed in the carrier gas. The raw material fluid G1 is adjusted. At this time, the raw material fluid G1 is adjusted so that the raw material powder is accompanied by the carrier gas supplied from the path 101 . As the raw material powder, those suitable for the type of inorganic spherical particles to be used can be used. For example, in addition to silica and alumina, magnetite and glass raw material powder can be used.

Next, the raw material fluid G1 is supplied to the raw material powder supply passage 3 of the burner 1 shown in FIGS. Oxygen gas G3 or oxygen gas G4 to be secondary oxygen is supplied. At this time, the supply amount of each fluid can be adjusted by, for example, a flow control unit (not shown) composed of a mass flow meter, an automatic valve, or the like.

As the oxygen gas G3 that becomes the primary oxygen and the oxygen gas G4 that becomes the secondary oxygen, for example, other than oxygen (oxygen gas), it is possible to use a combustion-supporting gas such as oxygen-enriched air. Further, the oxygen gas G3 and the oxygen gas G4 may be the same type of combustion-supporting gas, or may be different combustion-supporting gases. In this embodiment, by using oxygen gas or a combustion-supporting gas such as oxygen-enriched air as the oxygen gas G3 and the oxygen gas G4, a favorable and stable flame can be formed.

After that, the raw material fluid G1 is jetted from the raw material powder supply port 31 toward the inside of the combustion chamber 2, and a plurality of fuel gas jet ports 41, first oxygen gas jet ports 51 and second The fuel gas G2, the oxygen gas G3 that is primary oxygen, or the oxygen gas G4 that is secondary oxygen is jetted from the oxygen gas jet port 52, respectively. A flame (not shown) is formed in the combustion chamber 2 by burning the fuel gas G2, the oxygen gas G3, and the oxygen gas G4.

At this time, the oxygen gas G3 ejected from the plurality of first oxygen gas ejection ports 51 is mixed with the fuel gas G2 while forming a swirling flow in a plane perpendicular to the central axis J, and is combusted. be. In this way, the oxygen gas G3, which is primary oxygen, forms a swirling flow, so that the fuel gas G2 and the oxygen gas G3 are appropriately mixed, so that a good flame holding state can be maintained.

Further, the oxygen gas G4 ejected from the plurality of second oxygen gas ejection ports 52 toward the central axis J is mixed with the fuel gas G2 and the oxygen gas G3 and burned, thereby improving the flame holding state. can be retained.

Then, the surface of the raw material powder contained in the raw material fluid G1 is melted in the flame to generate spherical particles, whereby inorganic spherical particles can be produced. After that, the produced inorganic spherical particles are classified and collected by the cyclone 108 and the bag filter 109 shown in FIG.

According to the method for producing spherical inorganic particles of the present embodiment, the burner 1 of the present embodiment having the above configuration is used to produce spherical inorganic particles. The degree of vitrification of the inorganic spheroidized particles is increased because the amount of heat transferred to the raw material powder is also increased. In addition, since the raw material powder can be efficiently melted and spheroidized, the spheroidization degree of the inorganic spheroidized particles can also be increased, making it possible to produce inorganic spheroidized particles with an excellent spheroidization degree. .

<Effect>
As described above, according to the burner 1 for producing spherical inorganic particles of the present embodiment, the raw material powder supply port 31 arranged at the bottom of the combustion chamber 2 and the side wall 22 of the combustion chamber 2 are opened so that the raw material A fuel gas outlet 41 is provided so as to surround the powder supply port 31 and ejects the fuel gas G2 in a direction along the central axis J, and a fuel gas outlet 41 is opened in the side wall 22 of the combustion chamber 2 and surrounds the fuel gas outlet 41. a first oxygen gas outlet 51 for ejecting oxygen gas G3 while forming a swirling flow in a plane perpendicular to the central axis J; and a plurality of second oxygen gas ejection ports 52 that open at a position downstream of the central axis J and eject oxygen gas G4 toward the central axis J, and the momentum of the fuel gas G2 ejected from the fuel gas ejection port 41 is m _f , and the momentum m ₀ of the oxygen gas G4 ejected from the second oxygen gas ejection port 52 in the tangential direction to the central axis J is m ₀ , _θ . m ₀ , θ≦1.0].
In this way, the momentum [m _f ] of the fuel gas G2 ejected from the fuel gas ejection port 41 and the momentum [m ₀ ] of the oxygen gas G4 ejected from the second oxygen gas ejection port 52 in the tangential direction with respect to the central axis J By defining the relationship with the momentum [m ₀ , θ] within the optimum range, the mixing property of the fuel gas G2 and the oxygen gas G4 is improved, and the maximum temperature of the formed flame is increased. As a result, since the amount of heat transferred to the raw material powder is increased, the degree of vitrification of the inorganic spherical particles is increased, and the raw material powder can be efficiently melted and sphericalized. The degree of spheroidization is also enhanced.
Therefore, it is possible to produce inorganic spheroidized particles having an excellent degree of spheroidization without increasing the number of production facilities and increasing the costs associated therewith.

Further, according to the method for producing spherical inorganic particles according to the present invention, since it is a method for producing spherical inorganic particles using the burner 1 for producing spherical inorganic particles according to the present invention having the above configuration, Since the maximum temperature of the formed flame is increased, the amount of heat transferred to the raw material powder is also increased, so that the degree of vitrification of the inorganic spherical particles is increased, and the raw material powder is efficiently melted and sphericalized. Therefore, the degree of spheroidization of the inorganic spheroidized particles can also be increased.
Therefore, it is possible to produce inorganic spherical particles having an excellent degree of spheroidization without increasing the number of production facilities and increasing costs associated therewith.

Further, according to the inorganic spherical particles according to the present invention, the inorganic spherical particles obtained by using the burner 1 for producing inorganic spherical particles according to the present invention having the above configuration or the method for producing inorganic spherical particles. Therefore, it is inexpensive and has an excellent degree of spheroidization.

<Another form of the present invention>
Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the specific embodiments as described above, and is within the scope of the gist of the present invention described in the claims. Various modifications and changes are possible within.

The burner for producing inorganic spherical particles, the method for producing spherical inorganic particles, and the spherical inorganic particles according to the present invention will be described in more detail below with reference to examples, but the present invention is not limited to these.

<Burner for producing inorganic spherical particles>
In this embodiment, as shown in FIGS. 3 and 4, a combustion chamber 2, a raw material powder supply channel 3, a fuel gas supply channel 4, an oxygen gas supply channel 5, and a cooling water pipe 6 are provided. A burner having a structure in which a raw material powder supply port 31, a fuel gas ejection port 41, a first oxygen gas ejection port 51 and a second oxygen gas ejection port 52 are opened in the chamber 2, that is, one embodiment of the present invention described above. Inorganic spheroidized particles were produced using burner 1 described as configuration.

In this embodiment, the burner 1 is provided, and the powder feeder 102, the fuel supply equipment 104, and the oxygen supply equipment 105 as provided in the inorganic spherical particle production apparatus 100 illustrated in FIG. , a furnace 106, a cyclone 108, a bag filter 109, etc. were prepared to produce inorganic spherical particles.

<Conditions for producing inorganic spherical particles>
In this example, the above burner 1 was used to melt and spheroidize the raw material powder while forming a flame in the furnace 106 to produce inorganic spheroidized particles.
Specifically, after the raw material fluid G1 containing the raw material powder supplied from the powder feeder 102 is passed through flames in the combustion chamber 2 and the furnace 106 of the burner 1, the subsequent cyclone 108 and bag filter While classified by 109, the particles were collected by particle size to obtain spherical inorganic particles.
As the raw material powder, crushed silica having an average particle size D50 of 10 μm as measured by a wet particle size meter was used.
Ammonia was used as the fuel gas G2.
Basic operating conditions of the burner 1 in this embodiment are shown in Table 1 below.

In this example, among the inorganic spherical particles obtained by the burner 1, particles having a large particle size were recovered by the cyclone 108, and particles smaller than those recovered by the cyclone 108 were recovered by the bag filter 109.
Here, in the spheroidizing treatment of the raw material powder in the present embodiment, since the larger the particle size of the raw material powder, the larger the heat capacity, the more difficult it is to spheroidize. The evaluation was carried out using inorganic spheroidized particles.

As an evaluation index for the degree of spheroidization of the inorganic spheroidized particles in this example, the degree of vitrification of the spheroidized material as described above was used. Here, silica, which is the raw material powder, has a crystalline component derived from SiO ₂ , but in general, when such raw material powder is melted, the crystal transitions to an amorphous state. Therefore, in this example, the crystallinity of both the raw material powder silica and the silica after spheroidization (inorganic spheroidized particles) was evaluated using an X-ray diffraction device (XRD device; manufactured by Rigaku; trade name: SmartLab). After the measurement, the degree of vitrification was calculated and evaluated according to the following formulas (2) and (3).CuKa (wavelength=1.5418 Å) was used as the characteristic X-ray.
η=(Isaw/Iraw)×100 (2)
λ=100−η (3)
In the above formulas (2) and (3),
η: crystallinity Isaw: _SiO2 crystal intensity of the spheroidized product (X-ray peak intensity appearing at 2θ=26°)
Iraw: _SiO2 crystal intensity of raw silica (X-ray peak intensity appearing at 2θ = 26°)
λ : Vitrification degree

Table 2 below shows a list of burner combustion conditions (conditions for producing spherical inorganic particles) and test results in each example and comparative example. Further, the graph of FIG. 5 shows the vitrification degree in each example and comparative example.
Table 2 below shows the injection speed of ammonia (fuel gas G2) and secondary oxygen (oxygen gas G4) from the burner in each example, and each injection speed (m/s) is calculated by dividing the gas jetting amount (volumetric flow rate; m ³ /s) at one of the jetting ports provided in (1) by the cross-sectional area (m ² ) of the jetting port.

Below, among Examples 1, 2, 4 to 6 and Comparative Examples 3 and 7 shown in Table 2, for Example 1, the injection speed V _NH3 of ammonia, which is the fuel gas G2, and the oxygen gas, which is secondary oxygen, In addition to showing the ejection speed V _O2 of G4, each calculation process including the momentum m _f of ammonia and the momentum m ₀ and θ of oxygen gas G4 is shown with respect to [mf/m0, θ] shown in the above equation (1).

In the burner 1 used in this embodiment, the cross-sectional area of the fuel gas ejection port 41 is 0.00036 (m ² ), and the cross-sectional area of the second oxygen gas ejection port 52 is 0.00004 (m ² ). The ejection velocity V _NH3 of ammonia and the ejection velocity V _O2 of the oxygen gas G4, which is the secondary oxygen, are given by the following equations (4) and (5), respectively.
V _NH3 = 0.009 (Nm ³ /s)/0.00036 (m ² ) = 25 (m/s) (4)
_VO2 = 0.004 (Nm ³ /s)/0.00004 (m ² ) = 90 (m/s) (5)

In addition, θ: 45°, injection volume of ammonia: 0.009 (Nm ³ /s), injection volume of oxygen gas: 0.004 (Nm ³ /s), density of ammonia gas: 0.76 (kg/Nm ³ ), density of oxygen gas: 1.43 (kg/Nm ³ ), the momentum m _f of ammonia, the momentum m ₀ of oxygen gas G4 which is secondary oxygen, and the momentum m ₀ of oxygen gas G4 The momentum m ₀ , θ in the tangential direction with respect to the central axis J becomes the values shown in the following formulas (6) to (8).
_mf = 25 (m/s) x 0.009 (Nm ³ /s) x 0.76 (kg/m ³ ) = 0.17 (kg·m/s ² ) (6)
_m0 = 90 (m/s) x 0.004 ( ^Nm3 /s) x 1.43 (kg/ ^m3 ) = 0.51 (kg·m/ ^s2 ) (7)
_m0 , θ = 0.51 (kg·m/s ² ) x sin45 = 0.36 (kg·m/s ² ) (8)

[m _f /m ₀ , θ] represented by the above formula (1) is a value represented by the following formula (9) according to the calculation results of the above formulas (6) to (8).
m _f /m ₀ , θ = 0.17 (kg·m/s) / 0.36 (kg·m/s) = 0.48 (-) (9)

Further, in the present example, calculations and evaluations were performed in the same manner as in Example 1 above for Examples 2, 4 to 6 and Comparative Examples 3 and 7.

<Evaluation results>
As shown in Table 2 and the _graphs of FIG _. In Examples 1, 2, 4 to 6 in which the relationship between m ₀ and θ, which is the momentum in the tangential direction to the surface, satisfies the relationship represented by the above (1), the degree of vitrification was 87 to 93%. Thus, by satisfying the relationship represented by the above formula (1), the raw material powder can be efficiently melted and spheroidized, and inorganic spheroidized particles excellent in the degree of vitrification and the degree of spheroidization can be obtained. It could be confirmed.

On the other hand, Comparative Example 3 in which the value represented by the following formula [m _f /m ₀ , θ] is 1.44 and Comparative Example 7 in which the value is 1.08 have a vitrification degree of 75% or It is 77%, which is inferior to Examples 1, 2, 4 to 6, so it is considered that the degree of spheroidization is also inferior.

In this example, measurement data of the carbon content in the inorganic spheroidized particles was not obtained. It is known that when used, the carbon content in the resulting inorganic spheroidized particles is reduced.

From the results of the above-described examples, it can be concluded that raw material powder can be efficiently melted and spherically formed by producing inorganic spherical particles using the burner for producing inorganic spherical particles and the method for producing inorganic spherical particles according to the present invention. It has become clear that it is possible to produce inorganic spherical particles having an excellent degree of spheroidization.

INDUSTRIAL APPLICABILITY The burner for producing spherical inorganic particles and the method for producing spherical inorganic particles of the present invention are capable of producing spherical inorganic particles having an excellent degree of spheroidization without increasing the production facilities and increasing the costs associated therewith. It is very suitable for use in the production of inorganic spherical particles by melting inorganic powder raw materials in flames.

1... Burner for producing spherical inorganic particles (burner)
DESCRIPTION OF SYMBOLS 1A... Tip 2... Combustion chamber 22... Side wall 30... Powder dispersion plate 3... Raw material powder supply path 31... Raw material powder supply port 4... Fuel gas supply path 41... Fuel gas ejection port 5A (5)... First oxygen Gas supply path 51 First oxygen gas ejection port 5B (5) Second oxygen gas supply path 52 Second oxygen gas ejection port 6 Cooling water conduit 6a, 6b Flow path 61 Tip (for cooling water conduit)
J... Central axis 10... Inorganic spherical particle manufacturing apparatus G1... Raw material fluid G2... Fuel gas G3... Oxygen gas (primary oxygen)
G4... Oxygen gas (secondary oxygen)
W...Cooling water

Claims (9)

A burner for producing inorganic spheroidized particles, which has a bottomed cone-shaped combustion chamber that is open so that the tip side in the flame formation direction expands in diameter,
a raw material powder supply path for supplying raw material powder toward the combustion chamber using oxygen or oxygen-enriched air as a carrier gas;
a fuel gas supply path disposed so as to surround the raw material powder supply path from the outer peripheral side and supplying fuel gas toward the combustion chamber;
a supply path arranged to surround the fuel gas supply path from the outer peripheral side and supplying a combustion-supporting gas toward the combustion chamber;
The raw material powder supply path opens into the combustion chamber through a plurality of raw material powder supply ports provided in a powder distribution plate disposed at the bottom of the combustion chamber, and the plurality of raw material powder supply ports are provided. The mouth is arranged so as to surround the central axis of the inorganic spherical particle-producing burner,
A plurality of the fuel gas supply passages are provided so as to surround the raw material powder supply port in a plan view while opening in a side wall of the combustion chamber, and eject the fuel gas in a direction along the central axis. It has a gas outlet,
A plurality of supply passages for supplying the combustion-supporting gas are provided so as to open in a side wall of the combustion chamber and surround the fuel gas ejection port in plan view, and swivel in a plane perpendicular to the central axis. a first ejection port that ejects the combustion-supporting gas while forming a flow; and a second ejection port provided in a plurality so as to surround and ejecting the combustion-supporting gas toward the central axis,
Let _mf be the momentum of the fuel gas ejected from the fuel gas ejection port, and m be the momentum of the combustion-supporting gas ejected from the second ejection port _m0 in the direction orthogonal to the axial direction of the burner. A burner for producing spherical inorganic particles, characterized in that, when ₀ and θ, these relationships satisfy the relationship represented by the following formula (1).
m _f /m ₀ , θ ≤ 1.0 (1) 2. The burner for producing spherical inorganic particles according to claim 1, wherein the jet speed of said fuel gas jetted from said fuel gas jet port is 50 m/s or less. 3. The inorganic spheroidizer according to claim 1, wherein the raw material powder ejected from the raw material powder supply port is ejected at an angle that radially widens toward the downstream side of the combustion chamber. Burner for particle production. 4. The burner for producing spherical inorganic particles according to claim 3, wherein an ejection angle α of said raw material powder ejected from said raw material powder supply port with respect to said central axis is 0 to 15 degrees. The burner for producing spherical inorganic particles according to any one of claims 1 to 4, wherein the fuel gas is a gas containing no carbon. 6. The burner for producing spherical inorganic particles according to claim 5, wherein said fuel gas is ammonia or hydrogen. The burner for producing spherical inorganic particles according to any one of claims 1 to 6, characterized in that it has a cooling water pipe for circulating cooling water outside the combustion chamber. A method for producing spherical inorganic particles, which comprises using the burner for producing spherical inorganic particles according to any one of claims 1 to 7. Inorganic spherical particles obtained by the burner for producing inorganic spherical particles according to any one of claims 1 to 7, or by the method for producing inorganic spherical particles according to claim 8. .

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