WO2009107675A1 - Component for dispersing raw material - Google Patents

Abstract

Disclosed are: a component for dispersing a raw material, which has improved abrasion resistance; a spheroidized particle production apparatus; and a method for producing a spheroidized particle. Specifically disclosed is a component (10) for dispersing a raw material, which contacts with the raw material to cause the dispersion of the raw material. In the component (10), at least a part of the surface that contacts with the raw material is formed by a ceramic material.

Description

Raw material diffusion parts

The present invention relates to a raw material diffusion part, an apparatus for producing spheroidized particles, and a method for producing spheroidized particles.

The inorganic spheroidized particles generally have a raw material powder (here, having the same meaning as the inorganic powder in the present specification), a combustion flame (combustion gas) higher than the melting temperature of the raw material powder by a combustion device (gas combustion burner). It is manufactured by melting and spheroidizing the raw material powder in a powder melting furnace through it.

Patent Document 1 discloses an inorganic spheroidized particle manufacturing apparatus that manufactures inorganic spheroidized particles by maintaining the atmosphere (combustion gas) temperature in a flame formation region of a powder melting furnace within a predetermined temperature range.

Patent Document 2 discloses a burner for spherical particles in which a specific flame stabilizing plate and a diffusion means of a specific shape are provided in the front end portion of the raw material powder supply pipe.

Patent Document 3 discloses an inorganic spheroidized particle production apparatus in which a powder dispersion plate is attached to an inorganic powder supply passage for supplying an inorganic powder.

Metal materials such as SUS (stainless steel) and SKH (high-speed steel) have been used for these diffusion means and powder dispersion plates.

Prior art documents

JP 2002-166161 A JP 2000-346318 A JP, 2006-150241, A

An object of the present invention is to provide a raw material diffusion part having improved abrasion resistance, an apparatus for producing spheroidized particles, and a method for producing spheroidized particles.

The inventors of the present invention have found that the wear resistance of the raw material diffusion part is improved by using ceramics as a material for forming the raw material diffusion part for diffusing the raw material, and the present invention has been completed.

That is, the raw material diffusion component of the present invention is a raw material diffusion component for contacting the raw material and diffusing the raw material, and at least a part of the surface with which the raw material comes in contact is formed of ceramics.

Further, the spheroidized particle manufacturing apparatus of the present invention is a spheroidized particle manufacturing apparatus for supplying raw materials from a raw material supply path to a combustion flame in a melting furnace to melt and spheroidize, and at least a part of the surface is formed of ceramics. A raw material diffusion component for contacting the raw material and diffusing the raw material is provided in the raw material supply passage.

Further, the method for producing spheroidized particles of the present invention is a method for producing spheroidized particles in which a raw material is supplied from a raw material supply passage to a combustion flame in a melting furnace to melt and spheroidize the material. A source diffusion component in which at least a part of the surface is made of ceramic, the source material is brought into contact to diffuse the source material, and the source material after diffusion is supplied to the combustion flame for melting and spheroidizing It is.

According to the present invention, it is possible to provide a raw material diffusion part having improved wear resistance, and by using such a raw material diffusion part, it is possible to favorably manufacture spheroidized particles, such as having a high spheroidization rate. It is possible to provide an improved particle production apparatus and a method for producing spheroidized particles.

BRIEF DESCRIPTION OF THE DRAWINGS It is the schematic sectional drawing which showed the structural example of the spheroidized particle manufacturing apparatus which concerns on one Embodiment of this invention. It is the figure which showed the other structural example of the gas nozzle, and has shown the schematic sectional view (left figure) of the said gas nozzle, and the figure (right figure) seen from the melting furnace side. It is sectional drawing which showed an example of the combustion apparatus of FIG. 1 in more detail. FIG. 4 is a view showing an example of the configuration of the raw material diffusion component, which melts mesh-like (I), punch-like (II), honeycomb-like (III) and holes of irregular shape (IV) respectively It shows a view from the furnace side. It is sectional drawing which showed the structural example of a raw material diffusion component, what formed the whole raw material diffusion component with ceramics (I), what coat | covered a part of surface of raw material diffusion components with ceramics (II), raw material diffusion components The whole surface was covered with ceramics (III) is shown, respectively.

Explanation of sign

Reference Signs List 1 raw material powder feeder 2 raw material conveying gas supply passage 3 combustion device 4 raw material supply passage 5 fuel gas supply passage 6 combustion gas supply passage 7 fuel gas supply pipe 8 combustion gas supply pipe 9 combustion flame 10 raw material diffusion part 11 gas nozzle 12 Melting furnace 13 Burner outer cylinder

MODE FOR CARRYING OUT THE INVENTION

In the apparatus disclosed in Patent Document 3, by mounting the powder dispersion plate in the inorganic powder supply path, good inorganic spheroidized particles having a high spheroidization ratio can be obtained even when the raw material powder has large particle diameter. It can be manufactured efficiently. However, the powder dispersion plate used under an environment that can also be a high temperature is a case where it is formed using a relatively high wear resistant metal material such as SKH (high-speed steel) used conventionally. Also, it could not be said that the abrasion resistance was sufficient.

In the present invention, the raw material is preferably a fluid such as liquid fluid or powdery fluid widely, and after being diffused by the raw material diffusion component according to the present invention, it may be used as it is for final use. Processing such as melting into spheroidized particles may be performed. The following effects of the raw material diffusion component according to the present invention, for example, the effect of abrasion resistance, is that the raw material is a powdery fluid, and further, the powdery fluid whose powder is an inorganic powder It is remarkable in some cases.

Here, the inorganic powder refers to the following formula (1):
xA _m O _n / y B _p O _q (1)
(Wherein A and B are any metal atoms, xx1; y ≧ 0; m, n, p and q ≧ 1)
It is manufactured by using as a raw material an inorganic substance containing a component represented by Examples of the component represented by the formula (1) include Al ₂ O ₃ , ZrO ₂ , SiO ₂ , MgO, TiO ₂ , 3Al ₂ O ₃ · 2SiO ₂ , MgO · Al ₂ O ₃ , MgO · SiO ₂ , 2MgO. -SiO ₂ , ZrO ₂ · SiO _{2 and the} like can be mentioned.

As such an inorganic powder, for example, from the viewpoint of wear resistance, alumina (Al ₂ O ₃ ), zirconia (ZrO ₂ ), mullite (3Al ₂ O ₃ · 2SiO ₂ ), silicon carbide (SiC) is preferable. And at least one member selected from the group consisting of silicon nitride (Si ₃ N ₄ ), more preferably at least one selected from the group consisting of zirconia (ZrO ₂ ), silicon carbide (SiC) and silicon nitride (Si ₃ N ₄ ). It is a ceramic that is a seed. The parenthesis is the main component. In particular, in the case where the raw material powder is an inorganic powder, wear resistance can be achieved by forming at least a part of the surface to which the raw material in the raw material diffusion component 10 contacts with a ceramic having properties close to the inorganic powder. It can be effectively improved.

Further, the spheroidizing ratio means the weight ratio (%) of particles having a sphericity of 0.98 or more in the spheroidized particles. The sphericity is obtained by obtaining an image (photograph) of the particles with an optical microscope or a digital scope (for example, VH-8000 type manufactured by KEYENCE CORPORATION), and analyzing the obtained image to obtain a projection of the particles of the particles. Determine the area of the cross section and the perimeter of the cross section, and then {Circumferential length (mm) of the same area as the area of the particle projection cross section (mm ² )} / {peripheral length of the particle projection cross section (mm)} Is calculated and calculated by averaging the values obtained for each of 50 arbitrary spheroidized particles. The higher the sphericity, the higher the spheroidization rate.

FIG. 1 is a schematic cross-sectional view showing a configuration example of a spheroidized particle production device according to an embodiment of the present invention. In this spheroidized particle production apparatus, a raw material (raw material powder) made of powder is supplied by a fixed amount by the raw material powder feeder 1 and a raw material conveying gas (oxygen or oxygen) introduced from the raw material conveying gas supply passage 2 It is transported by enriched air (oxygen in the figure) and supplied to the raw material supply passage 4 in the combustion apparatus 3. As the raw material powder, the above-mentioned inorganic powder can be used. However, the raw material supplied to the raw material supply path 4 is not limited to the inorganic powder, and may be another raw material powder, or may be a raw material made of liquid other than powder.

The combustion apparatus 3 includes, in addition to the raw material supply passage 4, a fuel gas supply passage 5 disposed on the outer periphery of the raw material supply passage 4, and a combustion gas supply passage 6 disposed on the outer periphery of the fuel gas supply passage 5. Are configured in a multi-tube structure having That is, by arranging a plurality of (three in the drawing) tubular components having different diameters on the concentric axis, the raw material supply passage 4 is formed in the first tubular component having the smallest diameter, and the first tubular component A fuel gas supply passage 5 is formed between the second tubular component covering the outer side, and a combustion gas supply passage 6 is formed between the second tubular component and a third tubular component covering the outer side. .

Fuel gas (propane, butane, methane, LPG, etc.) is supplied to the fuel gas supply passage 5 via the fuel gas supply pipe 7. Further, combustion gas (oxygen or oxygen-enriched air) is supplied to the combustion gas supply passage 6 via the combustion gas supply pipe 8. The combustion device 3 is connected to the melting furnace 12, and the raw material powder, the fuel gas and the combustion gas introduced into the combustion device 3 are respectively supplied to the raw material supply passage 4, the fuel gas supply passage 5 and the combustion gas The gas flows in the same direction in the passage 6 and is supplied into the melting furnace 12 from one end on the melting furnace 12 side in the combustion apparatus 3. A jet port is formed at one end of the raw material supply passage 4, the fuel gas supply passage 5 and the combustion gas supply passage 6 on the melting furnace 12 side, and the combustion apparatus 3 and the melting furnace 12 are formed via these jets. And are connected.

A combustion flame 9 is formed in the melting furnace 12 by burning the fuel gas and the combustion gas supplied from the combustion device 3. In the vicinity of one end on the melting furnace 12 side in the raw material supply passage 4, the raw material diffusion component 10 in which a plurality of holes are formed is disposed, and the raw material powder conveyed by the raw material conveying gas is a raw material diffusion component The fuel is injected into the combustion flame 9 through the holes 10. The raw material powder is heated by the combustion flame 9 in the melting furnace 12, and at least a part of the raw material powder contacts and diffuses in the raw material diffusion part 10 while passing through the raw material diffusion part 10. The raw material powder thus diffused is melted or softened by being injected into the combustion flame 9, and is spheroidized by surface tension.

Here, “in the vicinity of one end on the melting furnace 12 side in the raw material supply passage 4” refers to the raw material supply from the center of the vertical cross section to the longitudinal direction of the raw material supply passage 4 at one end on the melting furnace 12 side of the raw material supply passage 4 Length at a distance corresponding to more than 0% and up to 20% of the total length of the path 4, preferably 1 to 10%, away from the center to the other end by a linear distance in the longitudinal direction It shall be. By providing the raw material diffusion component 10 in the vicinity of one end on the melting furnace 12 side in the raw material supply path 4, the dispersion of the raw material is improved, and the rushing speed of the particles into the flame is alleviated and stable spheroidization is achieved. .

However, the raw material diffusion component 10 is not limited to the configuration provided at the position as described above, but may be provided at another position in the raw material supply path 4 or the raw material powder feeder 1 and the raw material supply path It may be provided in the middle of the pipe connecting the four. Further, the number of the raw material diffusion parts 10 is not limited to one, and it is also possible to arrange the raw material diffusion parts 10 at a plurality of arbitrary positions selected from the above-mentioned respective positions.

The raw material powder is supplied to the melting furnace 12 through the raw material supply passage 4 of the combustion apparatus 3 in a state of being dispersed in the raw material conveying gas, but at that time, if the dispersibility of the raw material powder is poor, the spheroidizing process The particles are fused together, resulting in a shape defect and a large particle size. In addition, if the feed rate of the raw material powder is large and the residence time of the raw material powder in the melting furnace 12 is short, the raw material powder is not sufficiently spheroidized, and high-quality spheroidized particles can not be obtained. These tendencies are remarkable especially when the raw material powder is large particle size particles.

In the spheroidized particle production apparatus of the present invention, since the raw material powder is supplied to the melting furnace 12 through the raw material diffusion part 10 disposed in the raw material supply passage 4 in the combustion apparatus 3, The raw material powder can be supplied into the combustion flame 9, and furthermore, the raw material powder collides with the raw material diffusion part 10, so that the supply speed to the melting furnace 12 decreases, and the raw material powder is It can be maintained during the combustion flame 9. Therefore, according to the apparatus for producing spheroidized particles of the present invention, even when the average particle diameter of the raw material powder is large particle diameter of preferably 1 μm or more, more preferably 10 μm or more, still more preferably 100 μm or more. It is possible to efficiently produce good spheroidized particles having a high degree of spheroidization rate consisting of a body.

In addition, "the spheroidized particle which consists of a monodispersed body" means the spheroidized particle | grains which the particle | grains of raw material powder did not melt | fuse substantially each other, and were obtained corresponding to each raw material powder. Whether or not the spheroidized particles are in such a state can be easily grasped by observing an image of the particles with an optical microscope or a digital scope (for example, VH-8000 type manufactured by Keyence Corporation).

The raw material supply passage 4 is configured, for example, by attaching the gas nozzle 11 to the tip portion of a cylindrical tubular part (first tubular part). The gas nozzle 11 is located on the melting furnace 12 side of the raw material supply passage 4, and one end of the gas nozzle 11 on the melting furnace 12 side corresponds to the melting furnace 12 side on the raw material supply passage 4. Therefore, as a specific mode of arranging at least one raw material diffusion part 10 in the vicinity of one end on the melting furnace 12 side in the raw material supply path 4, an aspect of arranging at least one raw material diffusion part 10 in the gas nozzle 11 can be mentioned. .

From the viewpoint of making the dispersibility of the raw material powder and the retention state in the combustion flame 9 more stable, it is preferable to arrange at least one raw material diffusion component 10 in the gas nozzle 11, and the raw material diffusion component 10 in the gas nozzle 11. It is more preferable if two are attached. In addition, when arrange | positioning two or more of the raw material diffusion components 10, it is preferable to arrange | position so that each raw material diffusion components 10 may not mutually contact.

FIG. 2 is a view showing another configuration example of the gas nozzle 11, and shows a schematic cross-sectional view (left view) of the gas nozzle 11 and a view (right view) viewed from the melting furnace 12 side. In this example, two raw material diffusion parts A and B are disposed in the gas nozzle 11. These two raw material diffusion parts A and B respectively extend in a direction orthogonal to the longitudinal direction of the gas nozzle 11 (the raw material supply path 4), and are arranged parallel to each other at an interval. In the present invention, it is preferable to dispose a plurality of raw material diffusion components in the gas nozzle 11 from the viewpoint of increasing the spheroidization rate. With such an arrangement, the dispersion state and retention state of the raw material powder in the combustion flame 9 can be improved, and particles having a higher spheroidization rate and sphericity can be obtained. It is preferable to install one to four of the raw material diffusion parts of the present invention in the gas nozzle, and it is more preferable to install two to three of them.

The mounting state of the raw material diffusion parts A and B is not limited to the above configuration, but from the viewpoint of making the dispersibility of the raw material powder and the stagnation state in the combustion flame 9 more stable, the longitudinal direction of the raw material supply passage 4 It may be mounted substantially perpendicular to the above and in a state that it matches the cross-sectional shape perpendicular to the longitudinal direction of the raw material supply path 4 at the mounting position. That is, when the plurality of raw material diffusion components arranged along the longitudinal direction of the raw material supply passage 4 are viewed along the longitudinal direction, the respective raw material diffusion components are arranged such that the holes formed in the respective raw material diffusion components overlap each other May be arranged. Alternatively, at least one of the raw material diffusion parts may be rotated by a predetermined angle from the state in which the holes formed in the raw material diffusion parts overlap each other. From the viewpoint of increasing the spheroidization rate, the rotation angle is preferably 20 ° to 70 °, more preferably 30 ° to 60 °, and still more preferably 40 ° to 50 °.

FIG. 3 is a cross-sectional view showing an example of the combustion device 3 of FIG. 1 in more detail. In FIG. 3, the left side is the raw material powder supply side of the raw material supply passage 4, and the right side is the melting furnace 12 side of the raw material supply passage 4. The arrows in the figure indicate the direction of the raw material powder passing through the inside of the raw material supply passage 4, the direction of the fuel gas passing through the inside of the fuel gas supply passage 5, and the direction of the combustion gas passing through the inside of the combustion gas supply passage 6. Respectively. Also, a combustion device outer cylinder (third tubular component) covering the outside of the combustion gas supply passage 6 is indicated by reference numeral 13. The gas nozzle 11 is mounted in an elliptical area shown by a broken line in the figure.

From the viewpoints of the dispersibility of the raw material powder and the stabilization of the staying state in the combustion flame 9, a preferable structure of the raw material diffusion component 10 will be described. The porosity of the raw material diffusion component 10 is preferably 25 to 95%, more preferably 40 to 90%, and still more preferably 50 to 85%. The average pore diameter is preferably 0.1 to 5 mm, more preferably 0.2 to 4 mm, and still more preferably 0.5 to 3 mm in terms of circle diameter (refers to the diameter of a circle having the same hole area). The maximum opening diameter of the raw material diffusion component 10 is preferably 1 to 30 mm, more preferably 2 to 20 mm, in terms of a circle diameter. The thickness of the raw material diffusion component 10 is preferably 5 to 50%, more preferably 10 to 40%, as a ratio (thickness / diameter in circle) of the raw material diffusion component 10 with respect to the circle diameter.

Here, the open area ratio of the raw material diffusion part 10 is the ratio of the orthographic total area of the opening to the total area of the orthographic projection of the raw material diffusion part 10 (open area orthographic total area / raw material diffusion part orthographic total Defined as area). The average pore size is defined as the average of the circle-converted diameters of all the openings. The circle equivalent maximum opening diameter of the raw material diffusion component 10 is defined as the largest circle equivalent diameter among all the hole portions. The circle conversion diameter of the opening of the raw material diffusion part 10 is defined as the diameter of a circle having the same area as the orthographic projection area of the opening.

Examples of the shape of the raw material diffusion part 10 include mesh shapes, punch shapes (rencone shapes) in which the shape of the openings is circular or elliptical, honeycomb shapes, and shapes in which the shapes of the openings are irregular or irregular. Although not particularly limited to these shapes, at least one selected from the group consisting of mesh shape, punch shape and honeycomb shape is preferable from the viewpoint of easy production. Further, when the raw material powder is large particle size particles, from the viewpoint of obtaining good spheroidized particles with a higher spheroidization rate, a punch shape or a honeycomb shape is more preferable, and a punch shape is more preferable. When two or more raw material diffusion parts 10 are arranged in the raw material supply path 4, the raw material diffusion parts 10 of the same or different shapes can be optionally used, but the average pore diameter of the raw material diffusion parts 10 on the raw material powder supply side Of the raw material diffusion component 10 on the melting furnace 12 side may be smaller. Further, as described above, in the present invention, it is preferable to dispose a plurality of raw material diffusion parts in the gas nozzle 11 from the viewpoint of increasing the spheroidization rate. In this case, from the viewpoint of preventing nozzle clogging, raw material diffusion parts of the same shape may be used. For example, in the case of a configuration in which two raw material diffusion parts are provided, if one raw material diffusion part is rotated 45 ° from the state in which the holes formed in these two raw material diffusion parts overlap each other, spherical It is possible to obtain particles with higher conversion rate and sphericity.

FIG. 4 is a view showing an example of the structure of the raw material diffusion part 10, which has mesh-like (I), punch-like (II), honeycomb-like (III) and holes of irregular shape (IV). The figure seen from the melting furnace 12 side is shown.

In the example of FIG. 4I, the mesh-shaped raw material diffusion component 10 is configured by forming a plurality of rectangular openings in a lattice shape with respect to the plate-like component. In the example of FIG. 4 (II), the punch-shaped raw material diffusion component 10 is configured by forming a plurality of circular or elliptical openings at equal intervals. In the example of FIG. 4 (III), a honeycomb-shaped raw material diffusion component 10 is configured by forming a plurality of hexagonal openings so that the sides thereof face each other. In the example of FIG. 4 (IV), the raw material diffusion part 10 is comprised by forming multiple irregular or irregular holes.

However, the shape of the raw material diffusion component 10 is not limited to the shape as described above, and may have a configuration in which an opening having a shape different from that of the above example is formed. In addition, the raw material diffusion component 10 is not limited to one in which a hole for the raw material to pass through is formed, and various other configurations are possible as long as at least a part of the raw material can be contacted and diffused. It can be adopted.

In the raw material diffusion component 10 of the present invention and the spheroidized particle production apparatus using the same, at least a part of the surface of the raw material diffusion component 10 in contact with the raw material is formed of ceramics from the viewpoint of wear resistance of the raw material diffusion component 10 Is one major feature. The ratio of the portion where the ceramic is formed on the surface of the raw material diffusion component 10 is preferably 1 to 100%, more preferably 10 to 100%, still more preferably 50 to 100%, still more preferably 90 to 100%, More preferably, it is 100%. The case of substantially 100% is designed to cover the entire surface of the raw material diffusion component 10 with the above-mentioned ceramics, and includes the case where impurities are contained within the range where the effect of the present invention is not impaired. Here, covering means that the surface may be separately formed with respect to the inner component, or the inner component may be exposed as it is. Further, from the viewpoint of the wear resistance of the raw material diffusion part 10, the proportion of the portion formed of the ceramic is preferably 10 to 100%, not only the surface of the raw material diffusion part 10 but also the whole. % Is more preferable, 90 to 100% is more preferable, and substantially 100% is even more preferable. The case of substantially 100% means that all of the raw material diffusion component 10 is designed to be made of the above-mentioned ceramics, and includes the case where impurities are contained within the range where the effect of the present invention is not impaired. The raw material diffusion component 10 may be used under high temperature due to the heat from the combustion flame 9, but even under such high temperature, at least the surface of the raw material diffusion component 10 to be in contact with raw material as described above. Wear resistance can be improved by forming a part with ceramics.

The above ceramics is not particularly limited, but from the viewpoint of wear resistance, alumina (Al ₂ O ₃ ), zirconia (ZrO ₂ ), mullite (3Al ₂ O ₃ · 2SiO ₂ ), silicon carbide (SiC) And at least one selected from the group consisting of silicon nitride (Si ₃ N ₄ ). The parenthesis is the main component. In particular, in the case where the raw material powder is an inorganic powder, wear resistance can be achieved by forming at least a part of the surface to which the raw material in the raw material diffusion component 10 contacts with a ceramic having properties close to the inorganic powder. It can be effectively improved.

FIG. 5 is a cross-sectional view showing a configuration example of the raw material diffusion component 10, in which the entire raw material diffusion component 10 is formed of ceramics (I), and a part of the surface of the raw material diffusion component 10 is coated with ceramics II), the thing (III) which covered the whole surface of the raw material diffusion component 10 with ceramics is shown, respectively.

In the example shown in FIG. 5I, the plurality of openings 10a are formed in the plate-like component made of ceramic, so that the raw material diffusion component 10 made of ceramic as a whole is configured.

In the example of FIG. 5 (II), a plurality of apertures 10a are formed in a plate-like component formed of a metallic material such as SKH, and a part of the surface is covered with the ceramic film 10b. Is configured. The region in which the ceramic film 10b is formed is not particularly limited, but is preferably formed at least on the inner peripheral surface of the opening 10a, and as in the example of FIG. It is more preferable if it is also formed on the surface of the raw material powder supply side of the component 10.

In the example of FIG. 5 (III), a plurality of openings 10a are formed in a plate-like component formed of a metal material such as SKH, and the entire surface is covered with a ceramic film 10b to configure the raw material diffusion component 10 It is done.

The operation of the production apparatus of the present invention may be performed according to a conventional method. It is preferable that the flow velocity of the raw material transfer gas satisfy the following conditions.

The raw material powder is entrained in the raw material conveying gas and supplied to the combustion apparatus 3 and reaches the raw material diffusion part 10 of the raw material supply passage 4. The flow rate of the raw material conveying gas at that time is preferably It is 2 to 20 m / sec, more preferably 5 to 10 m / sec. If the flow rate of the raw material transfer gas is within such a range, sufficient dispersibility is obtained when the raw material powder collides with the raw material diffusion component 10, and the speed is appropriately reduced, and the residence time in the melting furnace 12 is good. It becomes.

The degree of deceleration is not particularly limited, but the speed of the raw material powder before passing through the raw material diffusion part 10 is I _{0, and} the speed of the raw material powder after passing through the raw material diffusion part 10 is I Then, it is preferable that their ratio I / I ₀ (%) satisfies I / I ₀ ≦ 50%. By setting the ratio I / I ₀ (%) in the above range, the residence time in the flame becomes long, and even particles having a large particle diameter can be suitably spheroidized. Note that I / I ₀ is calculated by measuring the passing speed of the raw material powder before and after the raw material diffusion component 10. The passing speed is determined, for example, by an optical method (high speed camera or the like).

The concentration of the raw material powder in the raw material conveying gas is preferably 0.1 to 10 kg / Nm ³ , more preferably 0.5 to 5 kg / Nm ³ from the viewpoint of securing sufficient dispersibility of the raw material powder. is there. The residence time in the melting furnace 12 is the time from when the raw material powder reaches the melting furnace 12 until the spheroidized molten particles fly out of the combustion flame 9 zone, and depending on the particle size of the raw material powder, 0.001 to It is preferably about 5 seconds. The temperature of the combustion flame 9 is not particularly limited, but generally, it is preferably about 1500 to 3000 ° C.

According to the spheroidized particle production apparatus of the present invention, it is possible to efficiently produce, for example, a good spheroidized particle having a high spheroidization rate and composed of a monodisperse and having an average particle diameter of about 1 to 500 μm. In addition, the average particle diameter of the raw material powder to be used does not substantially change by passing through the said manufacturing apparatus, and the average particle diameter of raw material powder and the average particle diameter of the obtained spheroidized particle are substantially Is the same.

The average particle size can be determined as follows. The diameter (mm) is measured in the case of sphericity = 1 from the particle projection cross section of the spheroidized particle, while the major axis diameter (mm) of the randomly oriented spheroidized particle is short in the case of sphericity <1. The axial diameter (mm) is measured to obtain (major axis diameter + minor axis diameter) / 2, and for each of the 100 spheroidized particles, the values obtained are averaged to obtain an average particle diameter (mm) Do. The major axis diameter and the minor axis diameter are defined as follows. When the particle is stabilized on a plane and the projected image of the particle on the plane is sandwiched by two parallel lines, the width of the particle at which the distance between the parallel lines is minimized is referred to as the minor axis diameter. The distance between two parallel lines in the direction perpendicular to the parallel lines is called the major axis diameter. The major axis diameter and the minor axis diameter of the spheroidized particle can be determined by obtaining an image (photograph) of the particle and analyzing the obtained image. In the case of the raw material powder, the "average particle diameter" is determined in the same manner.

Next, a method of producing spheroidized particles is provided, in which the raw material is supplied from the raw material supply passage 4 to the combustion flame 9 in the melting furnace 12 to melt and spheroidize it, provided in the raw material supply passage 4 and at least one of the surfaces thereof. The raw material is brought into contact with the raw material diffusion component 10 formed of a ceramic part to diffuse the raw material, and the diffused raw material is supplied to the combustion flame 9 to produce spheroidized particles for melting and spheroidizing The method will be described. The production method of the present invention can be suitably carried out by using the above-described spheroidized particle production apparatus. The production method of the present invention follows the method of operation of the conventional spheroidized particle production apparatus, preferably using the spheroidized particle production apparatus of the present invention under the above preferable conditions such as the flow rate of the raw material conveying gas. It is carried out by producing the activated particles.

According to the method of the present invention, for example, spherical casting sand suitable for producing a casting mold having excellent fluidity, high strength and a smooth surface, as described in JP-A 2004-202577, is efficiently used. It can be manufactured. In addition, please refer to the said gazette for details, such as manufacturing conditions.

The spherical casting sand obtained in this manner is very excellent in fluidity, and used alone or in appropriate mixing with a known casting sand so that the casting sand is contained in a predetermined ratio. . When the casting sand is used in the production of the mold, the casting sand can be efficiently regenerated as casting sand because the amount of binder used can be reduced. Such spherical casting sand can be suitably used for mold applications such as cast steel, cast iron, aluminum, copper and alloys thereof, and can also be used as a filler for metals, plastics and the like.

The inventors of the present application conducted various experiments to change the material of the raw material diffusion component 10 having the same shape, and to evaluate the wear resistance and the spheroidization rate for each. More specifically, the raw material diffusion parts 10 of the respective examples and comparative examples as described below are sequentially attached to a fixed attachment position in the spheroidized particle production apparatus as shown in FIG. The experiment was conducted by supplying raw material powder from the raw material supply passage 4 to the combustion flame 9 in the melting furnace 12 to melt and spheroidize it. The higher the sphericity, the higher the spheroidization rate.

As the raw material diffusion part 10, the mesh-like thing whose aperture ratio is 65%, average hole diameter is 2.0 mm, maximum open hole diameter is 2.0 mm, and thickness is 5 mm was used. The flow rate of the raw material transport gas was 11 m / s, and I / I ₀ was 35%. In addition, as the raw material powder, an inorganic powder having an average particle diameter of 0.19 μm made of mullite was used, and the concentration of the raw material powder was 39 kg / Nm ³ . In each of the following Examples and Comparative Examples, the weight loss ratio was determined by {(weight before experiment) − (weight after experiment)} / (weight before experiment) × 100 (%).

Example 1
The raw material diffusion part 10 which was entirely formed of alumina was attached to a spheroidized particle manufacturing apparatus, and the spheroidized particle manufacturing apparatus was continuously operated for 72 hours under the above conditions. The weight of the raw material diffusion part 10 before the experiment, the weight of the raw material diffusion part 10 after the experiment, the weight loss ratio, and the sphericity of the obtained particles are shown in Table 1, respectively.

Example 2
The raw material diffusion part 10 which was entirely formed of zirconia was attached to a spheroidized particle manufacturing apparatus, and the spheroidized particle manufacturing apparatus was continuously operated for 72 hours under the above conditions. The weight of the raw material diffusion part 10 before the experiment, the weight of the raw material diffusion part 10 after the experiment, the weight loss ratio, and the sphericity of the obtained particles are shown in Table 1, respectively.

Example 3
The raw material diffusion part 10 which was entirely formed of mullite was attached to the spheroidized particle manufacturing apparatus, and the spheroidized particle manufacturing apparatus was continuously operated for 72 hours under the above conditions. The weight of the raw material diffusion part 10 before the experiment, the weight of the raw material diffusion part 10 after the experiment, the weight loss ratio, and the sphericity of the obtained particles are shown in Table 1, respectively.

Example 4
The raw material diffusion part 10 which was entirely formed of silicon carbide was attached to a spheroidized particle production apparatus, and the spheroidized particle production apparatus was continuously operated for 72 hours under the above conditions. The weight of the raw material diffusion part 10 before the experiment, the weight of the raw material diffusion part 10 after the experiment, the weight loss ratio, and the sphericity of the obtained particles are shown in Table 1, respectively.

Example 5
The raw material diffusion part 10 which was entirely formed of silicon nitride was attached to the spheroidized particle manufacturing apparatus, and the spheroidized particle manufacturing apparatus was continuously operated for 72 hours under the above conditions. The weight of the raw material diffusion part 10 before the experiment, the weight of the raw material diffusion part 10 after the experiment, the weight loss ratio, and the sphericity of the obtained particles are shown in Table 1, respectively.

Example 6
According to the embodiment shown in FIG. 2, the gas nozzle 11 provided with two raw material diffusion parts A and B formed entirely of alumina is mounted on a spheroidized particle manufacturing apparatus, and the spheroidized particle manufacturing apparatus is manufactured under the above conditions. It ran continuously for 72 hours. As the raw material diffusion parts A and B, the same raw material diffusion parts 10 according to the first embodiment are used, and these raw material diffusion parts A and B are orthogonal to the longitudinal direction of the gas nozzle 11 (raw material supply passage 4) In order to extend in the direction, they were arranged in parallel at a distance of 35 mm from one another. Further, from the state in which the holes formed in the two raw material diffusion parts A and B overlap each other, one raw material diffusion part was rotated 45 °. The weight of the raw material diffusion parts A and B before the experiment, the weight and weight loss ratio of the raw material diffusion parts A and B after the experiment, and the sphericity of the obtained particles are shown in Table 1, respectively.

Comparative Example 1
The raw material diffusion part 10 which was entirely formed of SKH was attached to the spheroidized particle manufacturing apparatus, and the spheroidized particle manufacturing apparatus was continuously operated for 72 hours under the above conditions. The weight of the raw material diffusion part 10 before the experiment, the weight of the raw material diffusion part 10 after the experiment, the weight loss ratio, and the sphericity of the obtained particles are shown in Table 1, respectively.

As shown in the results of Table 1, when the raw material diffusion component 10 is formed of a ceramic such as alumina, zirconia, mullite, silicon carbide, silicon nitride, the weight loss ratio is higher than that of a material other than ceramic (for example, SKH) While the wear resistance can be dramatically improved, the sphericity of the particles can be improved, and particles with higher sphericity can be obtained. Further, as can be seen by comparing Example 1 and Example 6, by arranging a plurality of raw material diffusion parts in the gas nozzle 11, the sphericity of the particles is further improved, and particles having extremely high sphericity are obtained. be able to. Such an effect can be estimated to be obtained also when the raw material diffusion component 10 is formed of another ceramic, or when at least a part of the surface of the raw material diffusion component 10 is formed instead of the whole.

Claims (9)

A raw material diffusion part for contacting a raw material and diffusing the raw material, wherein at least a part of the surface with which the raw material comes in contact is formed of a ceramic. The raw material diffusion part according to claim 1, wherein the ceramic is at least one selected from the group consisting of alumina, zirconia, mullite, silicon carbide and silicon nitride. The raw material diffusion part of Claim 1 or 2 in which the hole for the powder contained in the said raw material to pass was formed. The raw material diffusion part according to claim 3, wherein the powder is an inorganic powder. 5. The raw material diffusion part according to claim 3, wherein the powder is diffused by the raw material diffusion part and melt-spheronized by a combustion flame. A spheroidized particle manufacturing apparatus for supplying raw material from a raw material supply path to a combustion flame in a melting furnace to melt and spheroidize it, wherein at least a part of the surface is formed of ceramics and contacts the above raw material to diffuse the raw material An apparatus for producing spheroidized particles, wherein a raw material diffusion part for making the raw material is provided in the raw material supply passage. The spheroidized particle manufacturing apparatus according to claim 6, wherein at least one of the raw material diffusion parts is provided in the vicinity of one end on the melting furnace side in the raw material supply passage. The melting furnace has a multi-pipe structure including the raw material supply passage, a fuel gas supply passage arranged on the outer periphery of the raw material supply passage, and a combustion gas supply passage arranged on the outer periphery of the fuel gas supply passage. The combustion apparatus and the melting furnace are connected to each other through the jet ports of the raw material supply passage, the fuel gas supply passage, and the combustion gas supply passage. The apparatus for producing spheroidized particles according to claim 6 or 7. A method for producing spheroidized particles in which a raw material is supplied from a raw material supply path to a combustion flame in a melting furnace to melt and spheroidize it, wherein the raw material supply path is provided and at least a part of the surface is formed of ceramics. A method for producing spheroidized particles, wherein the raw material is brought into contact with the raw material diffusion component to diffuse the raw material, and the diffused raw material is supplied to the combustion flame to melt and spheroidize the raw material.

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