KR20100123720A - Component for dispersing raw material - Google Patents

Abstract

Provided are a raw material diffusion component, a spheroidized particle production apparatus, and a method for producing spheroidized particles having improved wear resistance. In the raw material diffusion part 10 for contacting the raw material and diffusing the raw material, at least a part of the surface contacted with the raw material is formed of ceramics.

Description

Raw material diffusion part {COMPONENT FOR DISPERSING RAW MATERIAL}

TECHNICAL FIELD This invention relates to a raw material diffusion part, a spheroidized particle manufacturing apparatus, and a manufacturing method of a spheroidized particle.

The inorganic spheroidized particles generally pass raw material powder (which has the same meaning as the inorganic powder in this specification) in a combustion flame (combustion gas) above the melting temperature of the raw material powder by a combustion device (gas combustion burner), and powder melting furnace. It is manufactured by melt spheroidizing the said raw material powder in (iii).

Patent Literature 1 discloses an inorganic spheroidized particle production apparatus for producing inorganic spheroidized particles by maintaining an atmosphere (combustion gas) temperature in a flame formation zone of a powder melting furnace within a predetermined temperature range.

Patent Document 2 discloses a spherical particle burner provided with a specific retaining plate and a diffusion means having a specific shape in a tip end portion of a raw material powder supply pipe.

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

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

Japanese Laid-Open Patent Publication No. 2002-166161 Japanese Unexamined Patent Publication No. 2000-346318 JP 2006-150241 A

An object of the present invention is to provide a raw material diffusion component, a spheroidized particle production apparatus, and a method for producing spheroidized particles having improved wear resistance.

This inventor discovered that the wear resistance of the said raw material diffusion part improves by using ceramics as a material which forms the raw material diffusion part for diffusing a raw material, and came to complete this invention.

That is, the raw material diffusion part of this invention is a raw material diffusion part for contacting a raw material and diffusing the said raw material, and at least one part of the surface which the said raw material contacts is formed with ceramics.

In addition, the spheroidized particle manufacturing apparatus of this invention is a spheroidized particle manufacturing apparatus which supplies a raw material from a raw material supply path to the combustion flame in a melting furnace, and melts it and spheroidizes, At least one part of the surface is formed with ceramics, and contact | connects the said raw material, A raw material diffusion part for diffusing is provided in the raw material supply passage.

In addition, 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 path to a combustion flame in a melting furnace and melted and spheroidized. With respect to the formed raw material diffusion part, the raw material is contacted to diffuse the raw material, and the raw material after diffusion is supplied to the combustion flame to melt spheroidization.

According to the present invention, it is possible to provide a raw material diffusion component having improved wear resistance, and by using such a raw material diffusion component, a spheroidized particle production apparatus and a method for producing spheroidized particles, which can satisfactorily produce spheroidized particles, such as high spheroidization rate. Can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic sectional drawing which shows the structural example of the spheroidized particle manufacturing apparatus which concerns on one Embodiment of this invention.
Fig. 2 is a diagram showing another example of the configuration of the gas nozzle, and shows a schematic sectional view (left drawing) of the gas nozzle and a view (right drawing) seen from the melting furnace side.
3 is a cross-sectional view showing an example of the combustion device of FIG. 1 in more detail.
Fig. 4 is a view showing a structural example of a raw material diffusion part, showing the mesh shape (I), the punching shape (II), the honeycomb shape (III) and the shape of the openings in an indefinite shape (IV), respectively, as viewed from the melting furnace side. have.
Fig. 5 is a sectional view showing a structural example of a raw material diffusion part, in which the whole raw material diffusion part is formed of ceramics (I), a part of the surface of the raw material diffusion part is covered with ceramics (II), and the surface of the raw material diffusion part. The whole (III) which coat | covered the whole with ceramics is shown, respectively.

In the apparatus disclosed in Patent Literature 3, by attaching the powder dispersion plate to the inorganic powder supply passage, good inorganic spheroidized particles having high sphericity ratio can be efficiently produced even when the raw material powder is large particle size. However, even if the said powder dispersion plate used under the environment which may become high temperature is formed using relatively high wear-resistant metal materials, such as SKH (high speed steel) used conventionally, it cannot be said that wear resistance is sufficient.

In the present invention, the raw material is preferably a wide fluid such as a liquid fluid, a powder fluid, and may be provided for the final use as it is after being diffused by the raw material diffusion component according to the present invention. Processing such as melting and spherical particles may be performed. The following effects, for example, wear resistance effects of the raw material diffusion component according to the present invention are remarkable when the raw material is a powdered fluid, and further, the powdered material is a powdered fluid which is an inorganic powder.

In addition, an inorganic powder here is following formula (1):

Wherein A and B are any metal atoms, x≥1; y≥0; m, n, p and q≥1

It means what is produced by using the inorganic substance containing the component represented by a raw material. As the component of formula (1), for example, _{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, can be given a ZrO ₂ · SiO ₂ or the like.

As such inorganic powder, for example, from the viewpoint of wear resistance, preferably alumina (Al ₂ O ₃ ), zirconia (ZrO ₂ ), mullite (3Al ₂ O ₃ · 2SiO ₂ ), silicon carbide (SiC), silicon nitride ( At least one selected from the group consisting of Si ₃ N ₄ ), and more preferably at least one selected from the group consisting of zirconia (ZrO ₂ ), silicon carbide (SiC), and silicon nitride (Si ₃ N ₄ ). In addition, the said parenthesis is a main component. In particular, when the raw material powder is an inorganic powder, wear resistance can be effectively improved by forming at least a part of the surface of the raw material diffusion part 10 in contact with ceramics having properties close to the inorganic powder.

In addition, a sphericity ratio means the weight ratio (%) of the particle | grains whose sphericity is 0.98 or more in spheroidization particle | grains. The sphericity is obtained by obtaining an image (photograph) of the particle by an optical microscope or a digital scope (e.g., VH-8000, manufactured by Keyence Co., Ltd.), and analyzing the obtained image by image analysis to determine the area of the particle projection cross section of the particle and The peripheral length of the cross section was obtained, and then {circumferential length of a circle having the same area as the area of the particle projection cross section (mm)} / {the peripheral length of the particle projection cross section (mm)} were calculated, It calculates | requires by averaging the obtained value with respect to spheroidized particle, respectively. On the other hand, the higher the sphericity, the higher the spheroidization rate.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic sectional drawing which shows the structural example of the spheroidized particle manufacturing apparatus which concerns on one Embodiment of this invention. In this spheroidized particle manufacturing apparatus, the raw material (raw material powder) which consists of powder is supplied by the raw material powder feeder 1 by fixed quantity, and the raw material conveying gas (oxygen or oxygen enrichment) introduce | transduced from the raw material conveying gas supply path 2 It is conveyed by air; oxygen in the figure, and is supplied to the raw material supply path 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 inorganic powder, other raw material powder may be sufficient, and the raw material which consists of liquids other than powder may be sufficient as it.

In addition to the raw material supply path 4, the combustion device 3 is disposed on the fuel gas supply path 5 disposed on the outer circumference of the raw material supply path 4 and on the outer circumference of the fuel gas supply path 5. It is comprised by the multi-pipe structure which has the gas supply passage 6 for combustion. In other words, by arranging a plurality of pipe-like parts having different diameters (three in the drawing) on the concentric axis, a raw material supply passage 4 is formed in the first tubular part having the smallest diameter, and the first pipe A fuel gas supply path 5 is formed between the shaped part and the second tubular part covering the outside thereof, and the combustion gas supply path 6 is formed between the second tubular part and the third tubular part covering the outside thereof. ) Is formed.

The fuel gas (propane, butane, methane, LPG, etc.) is supplied to the fuel gas supply path 5 through the fuel gas supply pipe 7. Moreover, the combustion gas (oxygen or oxygen enriched air) is supplied to the combustion gas supply path 6 through the combustion gas supply pipe 8. The combustion apparatus 3 is connected to the melting furnace 12, and the raw material powder, the fuel gas, and the combustion gas introduced into the combustion apparatus 3 are the raw material supply passage 4, the fuel gas supply passage 5, and the combustion, respectively. The inside of the gas supply passage 6 flows in the same direction, and is supplied into the said melting furnace 12 from the one end of the melting furnace 12 side in the said combustion apparatus 3. Blowing ports are formed at one end of the melting furnace 12 side in the raw material supply passage 4, the fuel gas supply passage 5, and the combustion gas supply passage 6, respectively, and the combustion apparatus 3 is provided through these blowing holes. And the melting furnace 12 are connected.

In the melting furnace 12, the combustion flame 9 is formed by burning fuel gas and combustion gas supplied from the combustion device 3. The raw material diffusion part 10 in which the some hole was formed in the vicinity of the melting furnace 12 side in the raw material supply path 4 is arrange | positioned, and the raw material powder conveyed by the raw material conveying gas is these raw material diffusion parts. It is made to inject into the combustion flame 9 through the hole of 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 comes into contact with the raw material diffusion part 10 and diffuses in the process of passing through the raw material diffusion part 10. The raw material powder thus spread is melted or softened by being injected into the combustion flame 9 so as to be spherical by surface tension.

Here, "one end vicinity of the melting furnace 12 side in the raw material supply passage 4" means the longitudinal direction of the said raw material supply passage 4 in the one end of the melting furnace 12 side of the raw material supply passage 4 here. From the center of the vertical cross section with respect to a length corresponding to 20% beyond 0% of the total length of the said raw material supply path 4, Preferably it is a straight line distance from the said center by the length corresponding to 1 to 10%. Shall be referred to the position away from the other end side. By providing the raw material diffusion component 10 near one end of the melting furnace 12 side in the raw material supply passage 4, the dispersion of the raw materials is improved, and the inrush rate of the particles in the flame is alleviated to achieve stable spheroidization. do.

However, the raw material diffusion part 10 is not limited to the structure as provided in the above-mentioned position, It may be provided in the other position in the raw material supply path 4, The raw material powder feeder 1 and the raw material supply path 4 ) May be provided in the middle of the pipe to connect. In addition, the raw material diffusion part 10 is not limited to one, It is also possible to arrange | position the raw material diffusion part 10 in arbitrary some positions selected at each said position.

The raw material powder is supplied to the melting furnace 12 through the raw material supply passage 4 of the combustion device 3 in a state dispersed in the raw material conveying gas. If the dispersibility of the raw material powder is poor, the particles are fused together in the spheroidization process. This results in poor shape and a large particle size. In addition, when 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 cannot be obtained. This tendency is particularly remarkable when the raw material powder is large particle size.

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 component 10 disposed in the raw material supply passage 4 in the combustion device 3, the raw material powder is supplied in a good dispersion state. It can supply in the combustion flame 9, Furthermore, since a raw material powder collides with the raw material diffusion part 10, the supply speed to the melting furnace 12 falls, and it can hold | maintain the raw material powder in the combustion flame 9 with a suitable residence time. . Therefore, according to the spheroidized particle production apparatus of the present invention, even when the average particle diameter of the raw material powder is preferably 1 µm or more, more preferably 10 µm or more, and even more preferably 100 µm or more large particle size, Good spheroidized particle | grains with a high sphericity rate made can be manufactured efficiently.

In addition, "spheroidal particle which consists of a monodispersion" means the spheroidized particle obtained corresponding to each raw material powder, without the particle | grains of raw material powder being substantially fused together. Whether or not the spheroidized particles are in such a state can be easily determined by observing the image of the particles with an optical microscope or a digital scope (for example, VH-8000 manufactured by Keyence Corporation).

The raw material supply path 4 is comprised by attaching the gas nozzle 11 to the front-end | tip part of a cylindrical tubular part (1st tubular part), for example. The gas nozzle 11 is located on the melting furnace 12 side of the raw material supply passage 4, and one end of the melting furnace 12 side of the gas nozzle 11 is the melting furnace in the raw material supply passage 4 ( It corresponds to 12) side. Therefore, as a specific aspect which arrange | positions the at least 1 raw material diffusion part 10 in the vicinity of the end of the melting furnace 12 side in the raw material supply path 4, the raw material diffusion part 10 is provided in the said gas nozzle 11. The aspect which arrange | positions at least 1 is mentioned.

It is preferable to arrange | position at least one raw material diffusion part 10 in the gas nozzle 11 from a viewpoint of making the raw material powder dispersibility and the state of residence in the combustion flame 9 more stable, and in the said gas nozzle 11, It is more preferable to mount two raw material diffusion parts 10. In addition, when arranging two or more raw material diffusion parts 10, it is preferable to arrange | position so that each raw material diffusion part 10 may not contact each other.

FIG. 2 is a diagram showing another example of the configuration of the gas nozzle 11. FIG. 2 is a schematic sectional view (left diagram) of the gas nozzle 11 and a diagram (right diagram) seen 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, B extend in the orthogonal direction with respect to the longitudinal direction of the gas nozzle 11 (raw material supply path 4), respectively, and are arrange | positioned in parallel at intervals. In this invention, it is preferable to arrange | position a some raw material diffusion part in the gas nozzle 11 from a viewpoint of raising a sphericity rate. By such arrangement, the dispersion state of the raw material powder in the combustion flame 9, and the retention state are improved, and the particle | grains with a higher sphericity rate and sphericity can be obtained. It is preferable to provide 1-4 pieces of the raw material diffusion parts of this invention in a gas nozzle, and it is more preferable to provide 2-3 pieces.

The mounting state of the raw material diffusion parts A and B is not limited to the above configuration, but from the viewpoint of more stable the dispersibility of the raw material powder and the retention state in the combustion flame 9, the raw material supply path 4 is in the longitudinal direction. In addition, it may be mounted in a state substantially coincident with the cross-sectional shape perpendicular to the longitudinal direction of the raw material supply passage 4 at the mounting position. That is, when the raw material diffusion parts arranged in the plural directions along the longitudinal direction of the raw material supply passage 4 are viewed along the longitudinal direction, even when the raw material diffusion parts are arranged so that the holes formed in the respective raw material diffusion parts overlap each other. do. Moreover, the structure by which the at least 1 raw material diffusion part was rotated by the predetermined angle in the state which the hole provided in each raw material diffusion part overlaps each other may be sufficient. From a viewpoint of raising a sphericity rate, 20 degrees-70 degrees are preferable, 30 degrees-60 degrees are more preferable, and 40 degrees-50 degrees are more preferable.

3 is a cross-sectional view showing an example of the combustion device 3 of FIG. 1 in more detail. 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. Each arrow in the figure indicates the direction of the raw material powder passing through the raw material supply passage 4, the direction of the fuel gas passing through the fuel gas supply passage 5, and the combustion for passing through the combustion gas supply passage 6. The direction of gas is shown, respectively. In addition, the code | symbol 13 shows the combustion apparatus outer cylinder (3rd tubular component) which covers the outer side of the combustion gas supply path 6. The gas nozzle 11 is mounted in the elliptical area shown by the broken line in a figure.

The preferable structure of the raw material diffusion part 10 is demonstrated from the viewpoint of making the dispersibility of the raw material powder and the state of residence in the combustion flame 9 more stable. 25-95% is preferable, as for the porosity of the raw material diffusion part 10, 40-90% is more preferable, and 50-85% is still more preferable. The average pore diameter is preferably 0.1 to 5 mm, more preferably 0.2 to 4 mm, still more preferably 0.5 to 3 mm in terms of a circular equivalent diameter (referring to a diameter of circles having the same pore area). As for the largest opening diameter of the raw material diffusion part 10, 1-30 mm is preferable at a circular conversion diameter, and 2-20 mm is more preferable. When the thickness of the raw material diffusion part 10 is represented as a ratio (thickness / circular conversion diameter) with respect to the original conversion diameter of the raw material diffusion part 10, 5-50% is preferable and 10-40% is more preferable.

Here, the opening ratio of the raw material diffusion part 10 is the ratio of the total orthogonal projection area of the opening to the total area of the orthogonal projection of the raw material diffusion part 10 (opening area orthogonal projection area / raw material diffusion part orthogonal projection) Total area). An average hole diameter is defined as the average of the circular conversion diameter of all the opening part. The maximum opening diameter of the circular conversion of the raw material diffusion part 10 is defined as having the largest circular conversion diameter among all the openings. The circular 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 orthogonal projection area of the opening.

Examples of the shape of the raw material diffusion part 10 include a mesh shape, a punching shape (rotational shape) in which the shape of the opening is a circle or an ellipse, a honeycomb shape, and the shape of the opening is a release or an irregular shape. Although it is not specifically limited to these shapes, At least 1 sort (s) chosen from the group which consists of a mesh shape, a punching shape, and a honeycomb shape from a viewpoint of easy manufacture is preferable. In the case where the raw material powder is a large particle size, the punching shape or the honeycomb shape is more preferable, and the punching shape is more preferable from the viewpoint of obtaining a higher spheroidization rate and good spherical particles. When two or more raw material diffusion parts 10 are arranged in the raw material supply passage 4, raw material diffusion parts 10 having the same or different shapes can be arbitrarily used, and the average of the raw material diffusion parts 10 on the raw material powder supply side is used. The hole diameter side is large and the combination which becomes smaller the average hole diameter side of the raw material diffusion part 10 on the melting furnace 12 side may be sufficient. In addition, as mentioned above, in this invention, it is preferable to arrange | position a some raw material diffusion component in the gas nozzle 11 from a viewpoint of raising a sphericity rate. In this case, from the viewpoint of preventing nozzle clogging, a raw material diffusion component having the same shape may be used. For example, in the case of the structure in which two raw material diffusion parts are provided, when one of the raw material diffusion parts is rotated by 45 ° while the holes formed in the two raw material diffusion parts overlap each other, the spheroidization rate and the sphericity are more. Higher particles can be obtained.

FIG. 4 is a diagram showing an example of the configuration of the raw material diffusion part 10. The melting furnace 12 has a mesh shape (I), a punching shape (II), a honeycomb shape (III), and an open hole shape (IV), respectively. The figure seen from the side is shown.

In the example of FIG. 4 (I), the mesh-shaped raw material diffusion part 10 is comprised by forming two or more rectangular openings in a grid | lattice form with respect to a plate-shaped part. In the example of FIG. 4 (II), a plurality of circular or elliptical openings are formed at equal intervals to form a punching material diffusion component 10. In the example of FIG. 4 (III), the honeycomb raw material diffusion component 10 is constituted 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 constituted by forming a plurality of release or irregular openings.

However, the shape of the raw material diffusion part 10 is not limited to the above shape, The structure in which the opening of the shape different from the above example was formed may be sufficient. In addition, the raw material diffusion part 10 is not limited to the one in which the hole for passing the raw material is formed, and other various configurations can be adopted as long as the raw material diffusion part 10 can be contacted and diffused.

In the raw material diffusion part 10 and the spheroidized particle manufacturing apparatus using the same, at least one part of the surface which the raw material in the raw material diffusion part 10 contacts is formed from ceramics from the viewpoint of the abrasion resistance of the raw material diffusion part 10. It is one big characteristic to have been. 1-100% is preferable, as for the ratio of the part in which the ceramics are formed in the surface of the raw material diffusion part 10, 10-100% is more preferable, 50-100% is more preferable, 90-100% is Even more preferred, and 100% real is more preferable. In the case of the real 100%, the design which covers all the surfaces of the raw material diffusion part 10 with the said ceramics is made, and includes the case where an impurity is contained in the range which does not impair the effect of this invention. Here, coating may form the surface separately with respect to the internal structure, and the aspect which the internal structure is exposed to the surface as it may be may be sufficient. In addition, from the viewpoint of the wear resistance of the raw material diffusion part 10, the proportion of the portion formed of ceramics is preferably 10% to 100% not only on the surface of the raw material diffusion part 10 but also on the whole including the inside, and 50 100% is more preferable, 90-100% is still more preferable, and it is still more preferable that it is 100% real. In the case of the real 100%, the design which comprises the whole raw material diffusion part 10 from the said ceramics is made, and includes the case where an impurity is contained in the range which does not impair the effect of this invention. The raw material diffusion part 10 may be used at a high temperature by heat from the combustion flame 9. Even at such a high temperature, at least a part of the surface of the raw material diffusion part 10 in contact with the ceramic material may be used. The wear resistance can be improved by forming it.

The ceramics are not particularly limited, but from the viewpoint of abrasion resistance, alumina (Al ₂ O ₃ ), zirconia (ZrO ₂ ), mullite (3Al ₂ O ₃ · 2SiO ₂ ), silicon carbide (SiC), and silicon nitride (Si ₃₎ is at least one species selected from the group consisting of N ₄₎ is preferred. In addition, the said parenthesis is a main component. In particular, when the raw material powder is an inorganic powder, wear resistance can be effectively improved by forming at least a part of the surface of the raw material diffusion part 10 in contact with ceramics having properties close to the inorganic powder.

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

In the example of FIG. 5 (I), a plurality of openings 10a are formed in a plate-shaped component formed of ceramics, whereby the raw material diffusion component 10 formed entirely of ceramics is configured.

In the example of FIG. 5 (II), a plurality of openings 10a are formed in a plate-shaped part formed of a metal material such as SKH, and a part of the surface thereof is covered with the ceramic coating film 10b, whereby the raw material diffusion part 10 is formed. Consists of. The region in which the ceramic film 10b is formed is not particularly limited, but is preferably formed at least on the inner circumferential surface of the opening 10a. In the raw material diffusion component 10, as in the example of FIG. It is more preferable if it is also formed in the surface of the raw material powder supply side of the.

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

Operation of the manufacturing apparatus of the present invention may be performed by a conventional method. Moreover, it is preferable that the flow velocity of the gas for raw material conveyance, etc. satisfy | fill the following conditions.

The raw material powder is supplied with the gas for raw material conveyance to the combustion device 3 and leads to the raw material diffusion part 10 of the raw material supply passage 4, and as the flow rate of the raw material conveying gas at that time, preferably 2-20 m / sec, More preferably, it is 5-10 m / sec. When the flow velocity of the raw material conveying gas is in such a range, sufficient dispersibility is obtained when the raw material powder collides with the raw material diffusion part 10, and it is moderately decelerated to improve the residence time in the melting furnace 12.

The degree of the speed reduction is not particularly limited, assuming that the speed of the raw powder after the speed of the raw powder before passing through the material diffusion part 10 through the I _0, material diffusion part 10 I, the ratio of their It is preferable that I / I _O (%) satisfies I / I _O ≦ 50%. By setting the ratio I / I _O (%) in the above range, the residence time in the flame becomes long, and even a particle having a large particle size is preferably spheroidized. In addition, I / I _O is calculated by measuring the passing speed of the raw material powder before and after the raw material diffusion part 10. The passing speed is determined by an optical method (such as a high speed camera).

As raw material powder density | concentration in raw material conveyance gas, from a viewpoint of ensuring sufficient dispersibility of raw material powder, Preferably it is 0.1-10 kg / Nm <3>, More preferably, it is 0.5-5 kg / Nm <3>. The residence time in the melting furnace 12 refers to the time from when the raw material powder reaches the melting furnace 12 until the spherical molten particles scatter out of the combustion flame 9 zone, and depends on the particle size of the raw material powder. It is preferable that it is about 5 seconds. The temperature of the combustion flame 9 is not particularly limited, but is usually about 1500 to 3000 ° C.

According to the spheroidized particle manufacturing apparatus of this invention, the favorable spheroidized particle of about 1-500 micrometers of average particle diameters with a high sphericity ratio which consists of monodispersion can be efficiently manufactured, for example. In addition, the average particle diameter of the raw material powder used does not change substantially through the said manufacturing apparatus, and the average particle diameter of a raw material powder and the average particle diameter of the spheroidized particle obtained are substantially the same.

The average particle diameter can be obtained as follows. When sphericity from the particle projection cross section of the spheroidized particles = 1, the diameter (mm) was measured. On the other hand, when sphericity <1, the long axis diameter (mm) and the short axis diameter (mm) of the spheroidized particles randomly oriented were measured. It measures and obtains (long-axis diameter + short-axis diameter) / 2, and averages the obtained value with respect to arbitrary 100 spheroidized particle, respectively, and makes it as an average particle diameter (mm). The major and minor axis diameters are defined as follows. When the particle is stabilized on a plane and the projection image on the plane of the particle is sandwiched between two parallel lines, the width of the particle that minimizes the distance between the parallel lines is called a short axis diameter, and is perpendicular to this parallel line. The distance when the particles are sandwiched by two parallel lines in the direction is called the major axis diameter. The long axis diameter and short axis diameter of the spheroidized particle can be calculated | required by obtaining the image (photograph) of the said particle | grain, and image analysis of the obtained image. In the case of the raw material powder, the "average particle diameter" is similarly calculated.

Next, as a manufacturing method of the spheroidizing particle which supplies a raw material from the raw material supply path 4 to the combustion flame 9 in the melting furnace 12, and melts it, it is provided in the said raw material supply path 4, At least one part of the surface A method for producing spheroidized particles in which the raw material is brought into contact with the raw material diffusion component 10 formed of the ceramics to diffuse the raw material, and the raw material after diffusion is supplied to the combustion flame 9 to melt spheroidization will be described. . The manufacturing method of the present invention can be suitably carried out by using the spheroidized particle production device described above. The production method of the present invention is carried out by producing a spheroidized particle using the spheroidized particle production device of the present invention under the above preferred conditions such as the flow rate of the raw material conveying gas, according to the operation method of the conventional spheroidized particle production device. do.

According to the method of this invention, the spherical casting sand suitable for manufacturing the casting mold which is excellent in fluidity | liquidity, high strength, and smooth surface, for example described in Unexamined-Japanese-Patent No. 2004-202577 can be manufactured efficiently. In addition, refer to the said publication for the detail, such as a manufacturing condition.

The spherical foundry sand obtained in this way is very excellent in fluidity, and can be used alone or as appropriately mixed with a known foundry sand so that the foundry sand is contained at a predetermined ratio. When the foundry sand is used in the production of the mold, the amount of the binder to be used can be reduced, so that the foundry sand can be efficiently recycled as the foundry sand. Such spherical casting sand can be preferably used for casting 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.

<Examples>

The inventors of the present invention conducted various experiments in which the materials of the raw material diffusion component 10 having the same shape were changed in various ways, and the wear resistance and sphericity rate were evaluated for each. More specifically, with respect to the fixed mounting position in the spheroidized particle manufacturing apparatus as shown in FIG. 1, the raw material diffusion components 10 of each Example and the comparative example which are demonstrated below are mounted one by one, and are actually a raw material. It experimented by supplying raw material powder to the combustion flame 9 in the melting furnace 12 from the supply furnace 4, and melt spheroidizing. In addition, the higher the sphericity, the higher the sphericity.

As the raw material diffusion component 10, a mesh shape having a porosity of 65%, an average pore diameter of 2.0 mm, a maximum pore diameter of 2.0 mm, and a thickness of 5 mm was used. The flow velocity of the raw material conveying gas was 11 m / sec, and I / I ₀ was 35%. As the raw material powder, an inorganic powder having an average particle diameter of 0.19 µm made of mullite was used, and the raw material powder concentration was 39 kg / Nm 3. In addition, in each following example and the comparative example, the weight loss ratio was calculated | required as {(weight before experiment)-(weight after experiment)} / (weight before experiment) x 100 (%).

Example 1

The raw material diffusion part 10 formed by the whole alumina was attached to the spheroidizing particle manufacturing apparatus, and the said spheroidizing particle manufacturing apparatus was operated continuously for 72 hours on the said conditions. Table 1 shows the weight of the raw material diffusion part 10 before the experiment, the weight and loss ratio of the raw material diffusion part 10 after the experiment, and the sphericity of the obtained particles.

Example 2

The raw material diffusion part 10 formed by the whole zirconia was attached to the spheroidizing particle manufacturing apparatus, and the said spheroidizing particle manufacturing apparatus was operated continuously for 72 hours on the said conditions. Table 1 shows the weight of the raw material diffusion part 10 before the experiment, the weight and loss ratio of the raw material diffusion part 10 after the experiment, and the sphericity of the obtained particles.

Example 3

The raw material diffusion part 10 formed by the mullite as a whole was attached to the spheroidizing particle manufacturing apparatus, and the said spheroidizing particle manufacturing apparatus was operated continuously for 72 hours on the said conditions. Table 1 shows the weight of the raw material diffusion part 10 before the experiment, the weight and loss ratio of the raw material diffusion part 10 after the experiment, and the sphericity of the obtained particles.

Example 4

The raw material diffusion part 10 formed entirely from silicon carbide was attached to the spheroidizing particle manufacturing apparatus, and the said spheroidizing particle manufacturing apparatus was operated continuously for 72 hours on the said conditions. Table 1 shows the weight of the raw material diffusion part 10 before the experiment, the weight and loss ratio of the raw material diffusion part 10 after the experiment, and the sphericity of the obtained particles.

Example 5

The raw material diffusion part 10 formed entirely from silicon nitride was attached to the spheroidizing particle manufacturing apparatus, and the said spheroidizing particle manufacturing apparatus was operated continuously for 72 hours on the said conditions. Table 1 shows the weight of the raw material diffusion part 10 before the experiment, the weight and loss ratio of the raw material diffusion part 10 after the experiment, and the sphericity of the obtained particles.

Example 6

According to the aspect shown in FIG. 2, the gas nozzle 11 provided with the two raw material diffuser parts A and B which were entirely formed from the alumina was attached to the spheroidizing particle manufacturing apparatus, and the said spheroidizing particle manufacturing apparatus was continued for 72 hours on the said conditions. Drive. As the raw material diffusion parts A and B, the same thing as the raw material diffusion part 10 which concerns on the said Example 1 is used, and these raw material diffusion parts A and B are used in the longitudinal direction of the gas nozzle 11 (raw material supply path 4). They were arranged parallel to each other at a distance of 35 mm so as to extend in a direction orthogonal to. In addition, in the state where the holes formed in the two raw material diffusion parts A and B overlap with each other, one of the raw material diffusion parts was rotated by 45 °. The weight of the said raw material diffused parts A and B before an experiment, the weight of the raw material diffused parts A and B after an experiment, a weight loss ratio, and the sphericity of the obtained particle | grains are shown in Table 1, respectively.

Comparative Example 1

The raw material diffusion part 10 formed entirely from SKH was attached to the spheroidizing particle manufacturing apparatus, and the said spheroidizing particle manufacturing apparatus was operated continuously for 72 hours on the said conditions. Table 1 shows the weight of the raw material diffusion part 10 before the experiment, the weight and loss ratio of the raw material diffusion part 10 after the experiment, and the sphericity of the obtained particles.

As the result of Table 1 shows, when the raw material diffusion part 10 is formed of ceramics, such as alumina, zirconia, mullite, silicon carbide, and silicon nitride, compared with the case of forming from materials other than ceramics (for example, SKH), The weight loss ratio is very small, the wear resistance can be dramatically improved, and the sphericity of the particles can be improved to obtain particles with higher sphericity. 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 can be further improved, and particles having very high sphericity can be obtained. Such an effect can be estimated to be obtained even when the raw material diffusion part 10 is formed of other ceramics or when at least a part of the surface is formed of ceramic instead of the entire material diffusion part 10.

1 raw powder feeder
2 Gas supply passage for raw material conveyance
3 combustion device
4 raw material supply furnace
5 fuel gas supply furnace
6 Gas Supply Furnace
7 fuel gas supply pipe
8 Combustion gas supply line
9 combustion flame
10 raw material diffusion parts
11 gas nozzle
12 melting furnace
13 combustion unit outer cylinder

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 of the raw material contacting material is formed of ceramics. The method of claim 1,
And at least one member selected from the group consisting of alumina, zirconia, mullite, silicon carbide, and silicon nitride. The method according to claim 1 or 2,
A raw material diffusion part, characterized in that a hole for passing the powder contained in the raw material is formed. The method of claim 3,
A raw material diffusion part, wherein said powder is an inorganic powder. The method according to claim 3 or 4,
The powder is diffused by the raw material diffusion component, and melt spheroidized by a combustion flame. A spheroidized particle production apparatus for supplying a raw material from a raw material supply path to a combustion flame in a smelting furnace to melt spheroidization, wherein at least a part of a surface is formed of ceramics, and a raw material diffusion part for contacting the raw material to diffuse the raw material is supplied to the raw material. Spheroidal particle production apparatus characterized in that provided in the furnace. The method of claim 6,
At least one raw material diffusion part is provided in the vicinity of one end of the said melting furnace side in the said raw material supply path, The spheroidized particle manufacturing apparatus characterized by the above-mentioned. The method according to claim 6 or 7,
The melting furnace is composed of a multi-pipe structure having the raw material supply path, a fuel gas supply path disposed at an outer circumference of the raw material supply path, and a combustion gas supply path disposed at an outer circumference of the fuel gas supply path. It is connected to the combustion apparatus, The spherical particle manufacturing apparatus characterized by the connection of the said combustion apparatus and the said melting furnace being made through each injection port of the said raw material supply passage, the said fuel gas supply passage, and the said combustion gas supply passage. 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 and melted and spheroidized, wherein the raw material is provided in the raw material supply path, and at least a part of the surface thereof contacts the raw material diffusion part formed of ceramics. To diffuse the raw material, and supply the raw material after diffusion to the combustion flame to spheroidize the raw material.

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