Rotating device and method for producing fine particles

Abstract

To provide a technique capable of exhibiting a better pulverization effect in pulverization carried out by using a rotation device capable of performing three-dimensional rotation.SOLUTION: Pulverization is carried out by using a rotation device (ball mill) capable of three-dimensionally rotating (biaxial rotation) a container. The rotation device has a driving disk 6, a driven disk 9, and a transmission mechanism 10. Driving rotation about an X axis is converted into container rotation about a Z axis via the transmission mechanism 10. A pulverized object and a hard ball are placed into a spherical container 22. The device has a reversal mechanism, and appropriately switches rotation between forward rotation and backward rotation. The device exhibits a better effect particularly when fine particle sizes after pulverization are small (for example, 1 / 100 or less of hard ball size).SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a rotation device capable of three-dimensional rotation and a method for producing fine particles using the rotation device. [Background technology]

[0002] A ball mill is known as a type of grinding device that produces fine particles. In a ball mill, hard balls made of ceramic or metal and the material to be ground are placed in a cylindrical container and rotated (single-axis rotation, two-dimensional rotation) to grind the material to produce a fine powder (fine particles).

[0003] The two-dimensional rotation (single-axis rotation) is only in the circumferential direction, and the centrifugal force (revolution) and the counter-rotation (spinning) caused by that rotation cause the balls to fly to the other side and crush the sample. The movement of the balls is limited, and the crushing effect is also limited.

[0004] In contrast, with a rotating device (ball mill) capable of three-dimensional (two-axis) rotation, the balls move along the inner wall of the spherical container and trace complex trajectories within the container, making use of the entire interior of the spherical container (three dimensions), so a sufficient grinding effect can be expected.

[0005] A typical rotation device for three-dimensional rotation (two-axis rotation) is a device in which an external motor rotates together with an internal motor about a first axis, and the internal motor rotates a container or the like about a second axis (for example, Patent Document 1).

[0006] As a result of rotating the internal motor itself with an external motor, a large centrifugal force acts on the internal motor when it is rotated at high speed, which may cause it to break down. Furthermore, since it is difficult to align the center of gravity of the rotating body with the center of rotation due to the motor, high speed rotation is also difficult. In addition, the weight becomes heavy in order to rotate the container and the internal motor together, and the external motor needs to be made larger. This requires a lot of energy and generates heat loss.

[0007] In response to this, a rotating device having a transmission mechanism instead of an internal motor has been proposed (for example, Patent Document 2).

[0008] The rotation device according to Patent Document 2 is composed of a device main body, a housing, a drive motor, and a support plate. The rotational drive force of the drive motor is transmitted to the main body via a pulley.

[0009] The main body device is composed of an outer frame, an inner frame (container holding structure), a first circular plate (vertically placed), a second circular plate (horizontally placed), a first rotating shaft, and a second rotating shaft.

[0010] The rotational driving force of the drive motor is transmitted to the first rotating shaft via a pulley. The outer frame and the second rotating shaft rotate around the first rotating shaft.

[0011] The first disk has rubber on the circumferential surface and is in contact with the underside of the second disk to form a transmission mechanism. The rotational force of the first disk is transmitted to the second disk. The second disk and the inner frame rotate around the second rotation axis.

[0012] This allows the container to rotate around two axes simultaneously, namely the X-axis (first rotation axis) and the Z-axis (second rotation axis). This allows for three-dimensional rotation, which is called three-dimensional rotation.

[0013] In this way, the balls trace a complex trajectory inside the spherical container, and sufficient crushing effects can be expected. Compared to conventional rotating devices with two-dimensional rotation, the shape of the container makes it possible to suppress heat generation caused by collisions between the container and the balls. Furthermore, the transmission mechanism makes an internal motor unnecessary, making it possible to achieve a smaller size, lighter weight, and faster rotation (for example, 400 rpm). The transmission mechanism also makes it possible to suppress heat generation caused by driving the device. [Prior art documents] [Patent documents]

[0014] [Patent Document 1] JP 2002-316899 A [Patent Document 2] JP 2012-176331 A Summary of the Invention [Problem to be solved by the invention]

[0015] The container in Patent Document 2 is spherical. When the spherical container is rotated three-dimensionally at a constant speed, the balls trace a constant trajectory within the spherical container. When the inventor of the present application developed the rotation device in Patent Document 2 (basic form of the present application), he thought that a steady state was preferable.

[0016] While conducting various grinding tests, the inventors of the present application came to believe that this stationary orbit is what limits the performance of the three-dimensional rotating ball mill.

[0017] The present invention is intended to solve the above-mentioned problems, and has an object to provide a technology that can obtain a better crushing effect in crushing using a rotating device capable of three-dimensional rotation. [Means for solving the problem]

[0018] The present invention, which solves the above problem, is a rotation device that rotates a container three-dimensionally around a horizontal axis (X-axis) and an orthogonal axis (Z-axis). The rotation device has an inversion mechanism that switches between forward and reverse rotation.

[0019] The reversal creates a major change in the ball's trajectory, which can be expected to have an even greater crushing effect.

[0020] In the above invention, it is preferable that the apparatus further comprises a detection means for detecting a state of three-dimensional rotation, and a control device for issuing a switching command to the inversion mechanism based on state information detected by the detection means.

[0021] By detecting the state during three-dimensional rotation and controlling based on the state information, it is possible to perform appropriate inversion without unnecessary inversion.

[0022] In the above invention, preferably, the detection means detects a current load accompanying rotational driving.

[0023] In the above invention, preferably, the detection means detects sound accompanying rotational driving.

[0024] In the above invention, preferably, the detection means detects the temperature of the container.

[0025] In the above invention, preferably, the detection means detects vibration of the rotating device.

[0026] These detection means can detect the state during three-dimensional rotation.

[0027] In the above invention, preferably, the inversion mechanism is capable of inversion around a horizontal axis, inversion around an orthogonal axis, and inversion both around the horizontal axis and the orthogonal axis.

[0028] This is expected to change the ball's trajectory.

[0029] In the above invention, preferably, the rotation device includes a first rotation drive device, a first horizontal shaft rotated by the first rotation drive device, an outer rotating frame connected to the first horizontal shaft, a second rotation drive device provided on the opposite side to the first rotation drive device, a second horizontal shaft provided on the opposite side to the first horizontal shaft, penetrating one side of the outer rotating frame and rotated by the second rotation drive device, a driving disk connected to the second horizontal shaft and having a plate surface in a direction perpendicular to the second horizontal shaft, an orthogonal shaft having an axial direction perpendicular to the axial directions of the first horizontal shaft and the second horizontal shaft and provided on the outer rotating frame, an inner rotating frame connected to the orthogonal axis and holding the container, a driven disk connected to the orthogonal axis and having a plate surface in a direction perpendicular to the orthogonal axis, a transmission mechanism that transmits the rotational force of the driving disk to the driven disk, and a control device that individually controls the output of the first rotation drive device and the second rotation drive device.

[0030] The above rotation device can realize three-dimensional high-speed rotation. Two-axis rotation can be controlled separately.

[0031] In the above invention, preferably, the rotation device includes a rotation drive device, a horizontal shaft rotated by the rotation drive device, an outer rotating frame connected to the horizontal shaft, a driving disk connected to the horizontal shaft through one side of the outer rotating frame and having a plate surface in a direction perpendicular to the horizontal shaft, an orthogonal shaft having an axial direction perpendicular to the axial direction of the horizontal shaft and provided on the outer rotating frame, an inner rotating frame connected to the orthogonal shaft and holding the container, a driven disk connected to the orthogonal shaft and having a plate surface in a direction perpendicular to the orthogonal axis, a transmission mechanism that transmits the rotational force around the driving disk to the driven disk, and a control device that controls the output of the rotation drive device.

[0032] The above rotation device can realize three-dimensional high-speed rotation. One driving device can realize two-axis rotation.

[0033] The present invention, which solves the above problems, is a method for producing fine particles. A hard ball and a material to be crushed are placed in the container, and the container is rotated three-dimensionally, for example, in a forward direction and then in a reverse direction, to crush the material to be crushed into fine particles. Rotating in a forward direction and then in a reverse direction, or rotating in a reverse direction after a reverse rotation (returning to a forward direction) is called inversion.

[0034] The reversal creates a sudden and complex change in the ball's trajectory, which can be expected to have an even greater crushing effect.

[0035] In the present invention, the forward rotation and the reverse rotation are alternately repeated.

[0036] Repeated inversion can loosen the accumulated fine particles and promote pulverization.

[0037] In the present invention, the material to be ground is preferably silicon grains.

[0038] Silicon particulates are useful in a variety of applications.

[0039] In the present invention, the average diameter of the fine particles is preferably 1 / 100 or less of the average diameter of the hard balls, more preferably 1 / 500 or less, 1 / 1000 or less, and even more preferably 1 / 2500 or less.

[0040] Repeated inversion is particularly effective in grinding to produce finer particle sizes.

[0041] In the above invention, preferably, one of the first cross section perpendicular to the horizontal axis and the second cross section perpendicular to the perpendicular axis is substantially circular, and the other is substantially elliptical and asymmetric with respect to the minor axis. The other may be substantially elliptical and asymmetric with respect to the major axis.

[0042] Although a spherical container may be used, by using a container other than a spherical container, particularly by making it asymmetric about the axis, a sudden and complex change in the ball trajectory can be produced, and a further crushing effect can be expected. Effect of the Invention

[0043] In the present invention, a further grinding effect can be obtained in the grinding using a rotating device capable of three-dimensional rotation. [Brief description of the drawings]

[0044] [Figure 1] An example of a rotating device (cross-section) [Diagram 2] An example of a rotating device (perspective view) [Diagram 3] Another example of a rotating device (perspective view) [Figure 4] Another example of a rotating device (perspective view) [Diagram 5] Reverse control example [Figure 6] Reverse control example [Figure 7] Reverse control example [Figure 8] Reverse control example [Figure 9] Reverse control example [Figure 10] Inversion control flow diagram [Figure 11]Inversion control flow diagram (variation) [Figure 12] Effect of oval-shaped container [Figure 13] Effect of oval-shaped container [Figure 14] Spherical container [Figure 15] spindle-shaped spherical container [Figure 16] Combination of semi-oval and semi-spherical shapes [Figure 17] Egg-shaped container [Figure 18] Combination of semi-elliptical and semi-spherical shapes [Figure 19] A combination of semi-fusiform and semi-spherical shapes [Figure 20] Particle size distribution [Figure 21] Comparison Example 3 Image DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0045] <Basic configuration of rotating device> 1 and 2 are schematic diagrams of an example of a rotation device. Fig. 1 is a cross-sectional view, and Fig. 2 is a perspective view. The rotation device is composed of a device main body, a housing, electric motors 1 and 4 as rotation drive devices, and a support plate.

[0046] The device main body includes a first horizontal shaft 2, an outer rotating frame 3, a second horizontal shaft 5, a driving disk 6, an orthogonal shaft 7, an inner rotating frame 8, a driven disk 9, a transmission mechanism 10, and a control device 30. In the drawing, each of the components 1 to 10 is shown as a main device component 100 and is shown as a schematic configuration, with the control device 30 and signals related to the control being added.

[0047] The output shaft of the electric motor 1 (first rotary drive device) is coupled to a first horizontal shaft 2 via a pulley. The first horizontal shaft 2 is also coupled to an outer rotary frame 3. That is, when driven by the electric motor 1, the outer rotary frame 3 rotates around the first horizontal shaft 2 (around the axis line XX).

[0048] The output shaft of the electric motor 4 (second rotary drive device) is connected to a second horizontal shaft 5 via a pulley. The second horizontal shaft 5 is provided on the opposite side to the first horizontal shaft 2, and passes through one side of the outer rotary frame 3. A ball bearing is provided between the second horizontal shaft 5 and the outer rotary frame 3. The second horizontal shaft 5 is also connected to a driven disc 6. The driven disc 6 has a plate surface in a direction perpendicular to the second horizontal shaft 5.

[0049] That is, the driving disk 6 rotates around the second horizontal shaft 5 (around the line XX) by the driving of the electric motor 4. On the other hand, since the second horizontal shaft 5 is separated from the outer rotating frame 3, the driving force of the electric motor 4 is not directly transmitted to the outer rotating frame 3.

[0050] The orthogonal shafts 7, 7 are provided on the outer rotating frame 3. A ball bearing is provided between the orthogonal shafts 7, 7 and the outer rotating frame 3. The orthogonal shafts 7, 7 have an axial direction perpendicular to the axial direction of the first horizontal shaft 2 and the second horizontal shaft 5. The orthogonal shafts 7, 7 are coupled to the inner rotating frame 8.

[0051] That is, the inner rotating frame 8 is disposed inside the outer rotating frame 3, and is rotatable within the outer rotating frame 3 around the orthogonal axis 7 (ZZ line).

[0052] Furthermore, the orthogonal shaft 7 is coupled to the driven disk 9. That is, as the driven disk 9 rotates about the orthogonal shaft 7, the inner rotating frame 8 also rotates about the orthogonal shaft 7 (ZZ line). Even if the inner rotating frame 8 and the driven disk 9 rotate about the orthogonal shaft 7, this rotational force is not directly transmitted to the outer rotating frame 3.

[0053] The transmission mechanism 10 transmits the rotational force of the drive disk 6 to the driven disk 9 in a state in which the peripheral end face of the drive disk 6 faces the outer periphery of the plate surface of the driven disk 9 .

[0054] An oval-spherical container 23 is held within the inner rotating frame 8 (see Figs. 1 and 3).

[0055] <Basic operation of the rotating device> The control device 30 is capable of controlling the outputs of the electric motors 1 and 4 individually.

[0056] When the electric motor 1 is driven, the outer rotary frame 3 rotates around the line XX via the first horizontal shaft 2.

[0057] As the outer rotating frame 3 rotates, the orthogonal shafts 7, 7 provided on the outer rotating frame 3 also rotate around the line XX. Furthermore, the inner rotating frame 8 and the driven disk 9 also rotate around the line XX via the orthogonal shafts 7, 7.

[0058] When the electric motor 4 is driven, the driven disk 6 rotates around the line XX via the second horizontal shaft 5.

[0059] The driving disk 6 and the driven disk 9 rotate individually around the line XX, generating a rotational speed difference. The rotational speed difference around the line XX is transmitted to the driven disk 9 via the transmission mechanism 10, and the driven disk 9 rotates around the orthogonal axis 7 (around the line ZZ), and the inner rotating frame 8 also rotates around the line ZZ.

[0060] That is, the inner rotating frame 8 and the oval-spherical container 23 rotate around the XX line and also around the ZZ line. In other words, they rotate on two axes (three-dimensionally).

[0061] <Example of transmission mechanism> By individually controlling the output of electric motor 1 and electric motor 4, the number of rotations (rotation speed) around line XX and the number of rotations (rotation speed) around line ZZ can be individually controlled, which allows for even more complex behavior to be realized.

[0062] On the other hand, individual control of the electric motor 1 and the electric motor 4 tends to be complicated. When the rotation speed is increased, contact slippage occurs in the contact transmission mechanism, which may cause problems with the accuracy of speed control. In particular, when both the driving disk 6 and the driven disk 9 rotate around the XX line, contact slippage is likely to occur in the contact (contact) transmission mechanism.

[0063] Furthermore, when complex control is assumed, such as periodically increasing and decreasing the rotation speed, the transmission may not be able to keep up, and contact slippage may occur.

[0064] 1 and 2 is of a non-contact type and is composed of a plurality of first magnets 11 and a plurality of second magnets 12. A space 13 is formed between the first magnets 11 and the second magnets 12. In other words, the first magnets 11 and the second magnets 12 are not in contact with each other.

[0065] A plurality of first magnets 11 are disposed on the peripheral end surface of the driven disk 6 so that N poles and S poles alternate. A plurality of second magnets 12 are disposed on the outer periphery of the plate surface of the driven disk 9 so that N poles and S poles alternate.

[0066] When the driven disk 6 rotates, the first magnet 11 also rotates. The N pole of the first magnet 11 repels the N pole of the second magnet 12 and tries to attract the S pole of the second magnet 12. The S pole of the first magnet 11 repels the S pole of the second magnet 12 and tries to attract the N pole of the second magnet 12. By repeating this, the rotational force of the driven disk 6 around line XX is transmitted to the driven disk 9, and the driven disk 9 rotates around line ZZ.

[0067] In a non-contact transmission mechanism, contact slippage does not occur. As a result, precise speed control is possible. In addition, no heat is generated during the transmission of rotational force. Complex control such as periodically increasing and decreasing the rotational speed is also possible.

[0068] <Modification of Rotating Device> The rotating device is not limited to the above, as long as it can rotate the container in three dimensions.

[0069] Fig. 3 shows a modified example of the rotating device. There is no electric motor 4, and the second horizontal shaft 5 is fixed, so that the driven disk 6 is also fixed. Note that the same components as those of the rotating device shown in Figs. 1 and 2 are designated by corresponding reference numerals, and the reference numerals are omitted to simplify the drawings.

[0070] When the electric motor 1 is driven, the outer rotary frame 3 rotates around the line XX via the first horizontal shaft 2.

[0071] As the outer rotating frame 3 rotates, the orthogonal shafts 7, 7 provided on the outer rotating frame 3 also rotate around the line XX. Furthermore, the inner rotating frame 8 and the driven disk 9 also rotate around the line XX via the orthogonal shafts 7, 7.

[0072] At this time, the driven disk 9 rotates along the outer periphery of the driven disk 6. The rotational force around the line XX is transmitted to the driven disk 9 via the transmission mechanism 10, and the driven disk 9 rotates around the orthogonal axis 7 (around the line ZZ), and the inner rotating frame 8 also rotates around the line ZZ.

[0073] The inner rotating frame 8 and the spherical container 22 rotate around the line XX and also around the line ZZ, in other words, they rotate on two axes (three-dimensional rotation).

[0074] In this case, the number of rotations (rotation speed) around the ZZ line is proportional to the number of rotations (rotation speed) around the XX line. Individual control is not possible while the rotating device is in operation. On the other hand, the control can be simplified compared to individual control of two motors.

[0075] Fig. 4 shows another modified example of the rotating device. Specifically, it is a modified example of the transmission mechanism 10. The transmission mechanisms in Fig. 1 and Fig. 2 are of the non-contact type, whereas the transmission mechanism in Fig. 4 is of the contact type (abutment type).

[0076] An elastic body with a large coefficient of friction (e.g., a rubber band) is attached to the peripheral surface of the driven disk 6. Furthermore, grooves are provided in the rubber band. As a result, the peripheral surface of the driven disk 6 is pressed against the driven disk 9 via the transmission mechanism 10 made of rubber, generating frictional resistance between the two.

[0077] An annular, planar rubber may be attached to the outer periphery of the plate surface of the driven disc 9. In other words, it is sufficient that an elastic body is provided on either or both of the contact surfaces.

[0078] A modification of the transmission mechanism 10 may be a teeth meshing mechanism (not shown).

[0079] <Point of focus> In grinding using three-dimensional rotation, the balls collide with each other while rotating, rubbing against each other, and it is assumed that the material to be ground exists between the balls and between the ball and the container and is ground there.

[0080] However, when the material to be pulverized is pulverized and the particles become smaller, the ratio of the ball size to the particle size becomes larger. As a result, when considering, for example, a case where two balls collide and a fine particle is trapped between them, the smaller the particle size, the less chance there is for the particles to come into contact at the point where the balls collide. This suppresses the pulverization effect.

[0081] It is also assumed that the fraction of the fine particles in the gap between the container and the ball is reduced, and that they are pressed against the container wall by the ball and compacted. When this process is repeated, the fine particles accumulate. As a result, when the particles reach a certain size (for example, 1 / 100 or less of the ball size), the grinding effect is suppressed.

[0082] For example, this application focuses on silicon microparticles. Silicon microparticles are used as a negative electrode active material for lithium ion secondary batteries, as a silicide target raw material, and silicon microparticles that have been adsorbed with luminescent organic molecules to enhance luminescence are used as luminescent materials.

[0083] The aim is to crush silicon particles of about 0.01mm to 10mm into fine particles of 0.03μm to 90μm using balls with a diameter of about φ0.1mm to 30mm. At that time, we investigated how to further improve the crushing effect.

[0084] <Crushing Overview> Hard balls and the material to be crushed are placed in the spherical container 22, and the material is crushed by rotating it three-dimensionally at about 50 rpm to 800 rpm, preferably about 100 rpm to 400 rpm.

[0085] Although the size of the spherical container 22 is not limited, a maximum container diameter of 80 mm to 250 mm is used in the crushing test. In the case of a container other than a sphere as described later, the container size is set according to the sphere diameter.

[0086] The spherical container 22 is preferably made of the same material as the hard balls (for example, zirconia or alumina). Stainless steel may also be used.

[0087] An example of the object to be pulverized is silicon particles of about 0.01 mm to 10 mm (specific gravity 2.3 g / cm3), which are pulverized into fine particles of 0.03 μm to 90 μm. Depending on the size of the container, several grams to several hundred grams of the object to be pulverized are placed in the container. Note that the object to be pulverized is not limited to silicon particles.

[0088] The hard balls that are commonly used are made of ceramic or metal. An example of a ceramic is zirconia (specific gravity 5.7 g / cm 3 ) and alumina (specific gravity 4.0g / cm 3 Depending on the size of the container, balls with a diameter of about φ0.1 mm to 30 mm and weighing several tens of grams to several kilograms are placed in the container, depending on the material and amount of the material to be crushed.

[0089] In the present invention, the effect is particularly pronounced when the particle size after pulverization is fine (for example, 1 / 100 or less of the size of the hard balls).

[0090] <Invert> The inventors of the present invention believe that the steady trajectory of the balls in the spherical container is one of the factors limiting the crushing effect, and came up with the idea of ​​changing the ball trajectory by inverting the container.

[0091] In particular, in a spherical container, it is assumed that as the material to be crushed is crushed and the size of the material decreases, the material is pushed against the container wall by the balls and compacted, thereby suppressing the crushing effect.

[0092] The control device 30 can control the output of the electric motor 1 and the electric motor 4 individually. For example, it can rotate in the reverse direction. The reverse rotation command from the control device 30 constitutes a reversing mechanism. After rotating forward, it rotates in the reverse direction. This may be repeated.

[0093] The Example shows the results of crushing with inversion. Comparative Example 1-1 and Comparative Example 1-2 show the results of crushing without inversion. In Comparative Example 1-1, the crushing time is almost the same as in the Example. In Comparative Example 1-2, the crushing time is almost twice as long as in the Example. In order to make it easier to verify the effect, a spherical container 22 is used.

[0094] [Table 1] Table 1 shows the test conditions for the Example, Comparative Example 1-1, and Comparative Example 1-2. The rotation speed and ball size are common. The weight of the material to be pulverized and the number of balls (weight) are set so that the weight of the material to be pulverized / the weight of the balls are common.

[0095] [Table 2] Table 2 shows the test results for Example, Comparative Example 1-1, and Comparative Example 1-2. The grinding effect is evaluated based on the particle size distribution and the specific surface area.

[0096] From the particle size distribution, the maximum diameter, the amount of maximum diameter, the minimum diameter, the amount of minimum diameter, the volume-based average particle diameter MV, and d10, d50, and d90 are calculated.

[0097] The maximum diameter is the largest particle size among the measured samples. The minimum diameter is the smallest particle size among the measured samples. The MV (volume mean diameter) is the average particle size based on volume. The smaller the value, the greater the grinding effect.

[0098] d10, d50, and d90 are the particle sizes when the cumulative number is 10%, 50%, and 90%. The smaller the value, the greater the grinding effect.

[0099] The specific surface area is measured by placing the silicon particles as a sample in a measurement cell, degassing the cell for 60 minutes at 200°C, and then using a fully automatic gas adsorption measurement device (AUTOSORB-iQ2, manufactured by QUANTACHROME) with the BET method. Nitrogen gas is used as the measurement gas. The larger the value, the greater the grinding effect.

[0100] Since the silicon microparticles after pulverization are aggregated, they are treated as follows. Before measuring the particle size distribution, they are crushed using a mortar and pestle. The crushed silicon microparticles are put into an aqueous surfactant solution, and the silicon microparticles are dispersed by ultrasonic treatment for 3 minutes to prepare a silicon microparticle dispersion. Next, the particle size distribution of the silicon microparticles in the obtained silicon microparticle dispersion is measured using a laser diffraction / scattering particle size distribution measuring device (MT3300EX II, manufactured by Microtrack Bell Co., Ltd.).

[0101] When comparing the Example with the reversal and Comparative Example 1-1 without the reversal, the values ​​of the Example are smaller in all the indices of maximum diameter, minimum diameter, volume average diameter MV, d10, d50, and d90, indicating a greater grinding effect. Also, the value of the Example is larger in the index of specific surface area, indicating a greater grinding effect. This suggests that it is preferable to have a change in ball trajectory due to reversal.

[0102] When comparing the Example with inversion with Comparative Example 1-2 without inversion (pulverization time doubled), the values ​​of the Example are slightly smaller in all indices, including maximum diameter, minimum diameter, volume mean diameter MV, d10, d50, and d90, and the value of the Example is slightly larger in the index of specific surface area.

[0103] This suggests that changing the ball trajectory by reversing the ball will have a greater effect on crushing than unnecessarily lengthening the crushing time.

[0104] In particular, in a spherical container, it is believed that the material to be crushed adhering to the inner wall surface is peeled off by the inversion, which provides a further crushing effect.

[0105] On the other hand, in containers other than spherical (described later), depending on the shape, there is a risk that the material to be crushed may adhere or accumulate locally inside the container. It is believed that the material that adheres or accumulates locally will peel off or fall off when the container is turned over. This provides a further crushing effect.

[0106] <Inversion mode> In controlling the reversal, the forward rotation time and reverse rotation time, the respective rotation speeds, the time required to reach each rotation speed, the number of repetitions, etc. are set in advance.

[0107] Also, it is possible to select only inversion around the horizontal axis, only inversion around the orthogonal axis, or inversion both around the horizontal axis and the orthogonal axis.

[0108] When inverting both around the horizontal axis and the orthogonal axis, the inversion may be performed almost simultaneously, or only around the horizontal axis may be inverted first, or only around the orthogonal axis may be inverted, or only around the horizontal axis may be inverted first.

[0109] Either the forward rotation time or the reverse rotation time may be increased, or either the switching interval around the horizontal axis or the switching interval around the orthogonal axis may be increased.

[0110] Either the forward rotation speed (number of rotations) or the reverse rotation speed may be increased, or either the rotation speed around the horizontal axis or the rotation speed around the perpendicular axis may be increased.

[0111] Such a change in rotation causes a change in the steady state of the ball trajectory, suppressing adhesion of the material to be crushed to the inner wall surface, thereby achieving a further crushing effect.

[0112] <Reverse control> As mentioned above, it is assumed that as the grinding process progresses, the fine particles are pressed against the container wall and compacted. If this process is repeated, the fine particles will accumulate. This is thought to be the cause of the suppression of the grinding effect.

[0113] In response to the above phenomenon, the above state may be detected by a sensor or the like, and the control device 30 may issue a command to switch the rotation direction based on state information detected by the sensor.

[0114] Fig. 5 is an example of state detection. In the crushing effect suppression state, the energy required for crushing is reduced, and therefore the current load is also reduced. The electric motors 1 and 4 are provided with a current sensor 31. When the load current value measured by the current sensor 31 falls below a predetermined threshold, the control device 30 determines that the crushing effect is suppressed and switches the rotation direction.

[0115] Fig. 6 shows another example of state detection. When the material to be crushed starts to adhere, the sound becomes louder temporarily, and then when the crushing effect is suppressed due to the accumulation of fine particles, the collision sound between the ball and the container decreases. A sound sensor 32 is provided near the rotating device. Based on the change in sound (volume and frequency) detected by the sound sensor 32, the control device 30 determines that the crushing effect is suppressed and switches the rotation direction.

[0116] FIG. 7 shows another example of state detection. In the crushing effect suppressed state, heat generation caused by collisions between the balls and the container is also reduced. The temperature inside the container also becomes lower. The accumulated fine particles move less and their temperature also becomes lower. A temperature sensor 33 is provided near the rotating device. The temperature sensor 33 is, for example, of a non-contact infrared type. When the temperature measured by the temperature sensor 33 falls below a predetermined threshold value, the control device 30 determines that the crushing effect is suppressed and switches the rotation direction.

[0117] Fig. 8 shows another example of state detection. In the crushing effect suppression state, vibrations caused by collisions are reduced. An acceleration sensor 34 is provided on the support of the rotating device. It is preferable that the acceleration sensor 34 is provided in a location that does not involve rotation. Based on the vibration change detected by the acceleration sensor 34, the control device 30 determines that the crushing effect is suppressed and switches the rotation direction.

[0118] FIG. 9 shows another example of state detection. In the crushing effect suppression state, the vibration caused by the collision is reduced. An acceleration sensor 35 is provided on one of the balls in the container. Based on the vibration change detected by the acceleration sensor 35, the control device 30 determines that the crushing effect is suppressed and switches the rotation direction. For example, the vibration mode changes when the crushing opportunity decreases. Also, in the fine particle accumulation state, the vibration caused by the collision between the ball and the container changes.

[0119] As described above, by detecting the state during three-dimensional rotation and performing control based on the state information, unnecessary inversion is avoided and appropriate inversion can be performed.

[0120] In the above control example, if the crushing effect suppression state is resumed after the inversion operation, the inversion operation is repeated at short time intervals, thereby releasing the accumulation of fine particles.

[0121] In the above control example, the status information detected by the sensor is compared with a predetermined threshold value to issue a switching command, but as a variant, the correlation between the status information detected by the sensor and the grinding size may be determined by machine learning, and a control model generated by machine learning may be applied to issue a switching command.

[0122] Furthermore, when the control device 30 determines that the reversal has almost no effect based on the state information detected by the sensor, it stops the rotation. The determination of the presence or absence of the reversal effect may be made by comparing with the state information before the reversal, by comparing with a threshold value, or by applying a control model generated by machine learning.

[0123] Fig. 10 is a schematic flow diagram of the above control. State detection is performed simultaneously with rotation driving (step 1). The control device 30 judges whether the crushing effect suppression state (or the state in which the material to be crushed starts to adhere to the inner wall surface) has been detected (step 2). The control device 30 continues rotation driving and state detection (step 1 → step 2 → step 1 → step 2...) unless it detects the crushing effect suppression state.

[0124] When the control device 30 detects the crushing effect suppressed state, it outputs a reverse command (step 3). Rotational drive by reverse rotation and state detection are continued.

[0125] The control device 30 judges whether the reversal has had an effect (step 4). If it judges that the reversal has had an effect, it continues the rotational drive by the reversal and the state detection, and repeats steps 1 to 4. If the control device 30 judges that the reversal has no effect, it stops the rotational drive.

[0126] Fig. 11 is a schematic flow diagram of the above control according to the modified example. State detection is performed simultaneously with rotation driving (step 1). The control device 30 judges whether the crushing effect suppressed state (or the state in which the material to be crushed starts to adhere to the inner wall surface) has been detected (step 2). The control device 30 continues rotation driving and state detection (step 1 → step 2 → step 1 → step 2,...) unless it detects the crushing effect suppressed state.

[0127] When the control device 30 detects the crushing effect suppressed state, it outputs a reverse command (step 3). Rotational drive by reverse rotation and state detection are continued.

[0128] The control device 30 judges whether a predetermined time has elapsed (step 5). If it judges that the predetermined time has not elapsed, it continues the rotational drive by reverse rotation and the state detection, and repeats steps 1 → 2 → 3 → 5. If it judges that the predetermined time has elapsed, it stops the rotational drive.

[0129] <Grinding using non-spherical containers> The inventors of the present application believe that the constant orbit of the balls within the spherical container is one of the factors limiting the crushing effect, and came up with the idea of ​​changing the shape of the spherical container 22.

[0130] Examples of containers other than spherical shapes include an elliptical sphere, an egg-shaped sphere, a spindle-shaped sphere, an oblong sphere, a combination of a semi-elliptical sphere and a hemisphere, a combination of a semi-egg-shaped sphere and a hemisphere, a combination of a semi-spindle-shaped sphere and a hemisphere, etc. For convenience of explanation, an elliptical sphere will be taken as an example.

[0131] FIG. 12 is an image diagram for estimating the difference in effect between the spherical container 22 and the oval spherical container 23.

[0132] When the spherical container 22 is rotated three-dimensionally, centrifugal force causes the hard ball to move along the inner wall surface of the spherical container 22. After a predetermined time has passed, the ball reaches a stationary orbit.

[0133] On the other hand, as the material is crushed and becomes smaller in size, it is assumed that it is pushed and compacted by the centrifugal force and the balls against the container wall. As a result, the hard balls rarely come into contact with the material, and sufficient crushing effect cannot be obtained.

[0134] When the oval-spherical container 23 is rotated three-dimensionally, the centrifugal force causes the hard balls to move along the inner wall surface of the oval-spherical container 23. Some of the hard balls moving along the inner wall surface of the oval-spherical container 23 change their trajectory due to the change in curvature and move away from the inner wall surface. At this time, some of the material to be pulverized (fine particles) that has become smaller in size is not continuously subjected to pressure against the container wall by the balls, but is appropriately released and moves away from the inner wall surface.

[0135] The material that is separated from the inner wall surface has more chances to come into contact with the hard balls again. As a result, further pulverization effect can be expected. In other words, finer particles can be produced.

[0136] In addition, while in the spherical container 22 the balls follow a steady trajectory and collide less with the container walls, in the elliptical container 23 the ball trajectory changes and collisions with the container walls increase. Any material to be crushed that exists between the balls and the container walls is crushed. On the other hand, the change in the ball trajectory also increases the chances of balls colliding with each other. Furthermore, changes in acceleration occur, making the collisions more complex and increasing the collision energy.

[0137] In this way, the movement of balls in containers other than the spherical container is thought to be more complicated than that in a spherical container. The movement of one ball has been explained above, but there are many balls in the container, and if the movement of one ball becomes complicated, it is thought that the number of collisions with other balls and the inner wall of the container will also increase. Compared to a spherical container, the current value (energy) required when operating an oval sphere (see Figure 14) or an egg-shaped container (see Figures 16 and 17) at the same rotation speed is 1.5 to 2 times higher.

[0138] Meanwhile, after 30 minutes, the temperature of the spherical container barely rose to 1.6°C compared to room temperature, but the temperature rose by 12.5°C in the egg-shaped container and 18°C ​​in the oval sphere. This is thought to be because, in containers other than the spherical container, the movement of the balls became more complex, and the number of collisions between the balls and the inner wall of the container also increased significantly.

[0139] In this respect, by replacing the spherical vessel 22 with an oval vessel 23, a further pulverizing effect can be expected.

[0140] FIG. 13 is a diagram for explaining the difference in effect between the spherical container 22 and the oval spherical container 23 from another perspective.

[0141] In order to ensure the grinding effect of the ball mill, the specific gravity of the hard ball is generally relatively heavy (e.g., zirconia specific gravity 5.7 g / cm 3 degree, alumina specific gravity 4.0g / cm 3 degree).

[0142] As a result, the influence of the weight of the hard ball is large, and in a three-dimensional rotation at a low rotation speed (e.g., about 50 rpm), the hard ball may not be able to run up the inner wall of the spherical container 22. Even in a three-dimensional rotation at a high rotation speed (e.g., about 200 rpm), it takes a certain time for the hard ball to run up the inner wall of the spherical container 22 and draw a trajectory over the entire surface of the spherical container.

[0143] In contrast, in three-dimensional rotation, when the major axis of the oval-spherical container 23 is horizontal, the hard balls are more likely to run up the inner wall of the oval-spherical container 23. Even with three-dimensional rotation at a low rotation speed (e.g., about 50 rpm), the hard balls can run up the inner wall of the oval-spherical container 23. With three-dimensional rotation at a high rotation speed (e.g., 200 rpm or higher), the hard balls run up the inner wall of the oval-spherical container 23 and trace a trajectory over the entire surface of the oval-spherical container in a short period of time. As a result, the grinding time is shortened. The rotation device of the present invention is capable of high-speed rotation of 400 rpm.

[0144] In this respect, by replacing the spherical vessel 22 with an oval vessel 23, a further pulverizing effect can be expected.

[0145] <Other containers> Examples of containers other than spherical shapes include ellipsoidal spheres, spindle-shaped spheres, egg-shaped spheres, oval spheres, combinations of semi-ellipsoidal spheres and hemispheres, combinations of semi-spindle-shaped spheres and hemispheres, combinations of semi-oval spheres and hemispheres, etc. Containers other than ellipsoidal spheres will now be described.

[0146] Figure 14 shows an example of an oval-shaped container. An oval sphere is the path of an oval rotated around its major axis. An oval is a circle with a straight line in the major axis direction.

[0147] Figure 15 shows an example of a spindle-shaped spherical container. A spindle-shaped sphere is the path of a spindle-shaped circle rotated around its major axis. The spindle-shaped circle is an ellipse with the major axis end extremely tapered.

[0148] Figure 16 shows an example of a combination of a semi-egg-spherical container and a hemispherical container. Since it has a similar shape to the egg-shaped spherical container, it is considered to be substantially an egg-shaped spherical container.

[0149] FIG. 17 shows an example of an egg-shaped container. The egg-shape is similar to an ellipse, but is a roughly ellipse with an asymmetric curvature with respect to the minor axis. That is, the curvature is large at one end of the major axis and small at the other end of the major axis, and the curvature changes continuously between the two ends. Here, mathematically, the shortest line segment connecting the midpoint of the major axis and a point on the egg-shaped line is defined as the minor axis, but in this application, for ease of explanation, the line extending perpendicularly from the midpoint of the major axis (or the longest line segment among the lines extending perpendicularly from the major axis) is defined as the minor axis.

[0150] The egg-shaped ellipse can be expressed as the following locus: x = ((r + sinθ) 2 -a 2 ) 1 / 2 y=cosθ Here, θ is a parameter, and r and a are arbitrary constants. For typical chicken eggs, a=2.5, r=3.0. When applied to the container of the present invention, a=1.0-6.0, r=2.5-8.0 are preferable. By setting r and a appropriately, it is possible to express shapes such as a pear shape and a teardrop shape.

[0151] The gradual change in curvature of the egg creates a sudden and complex change in the ball trajectory, which can be expected to have an even more crushing effect.

[0152] The inventors of the present application have confirmed the crushing effect of various containers and have found that an egg-shaped spherical container is suitable.

[0153] In addition, even if a bun-shaped ellipse having an asymmetric curvature about its major axis is used instead of an egg-shaped ellipse having an asymmetric curvature about its minor axis, a sudden and complex change in the ball trajectory can be expected.

[0154] Fig. 18 is an example of a combination of a semi-elliptical sphere and a semi-sphere. Fig. 19 is an example of a combination of a semi-fusiform sphere and a semi-sphere. It is believed that the effect of having an asymmetric curvature with respect to the axis can also be obtained with these containers.

[0155] <Confirmation of crushing effect using containers other than spherical> Reference Example 1 shows the results of crushing using a combination of a semi-egg-shaped spherical container and a hemispherical container (see FIG. 16). Reference Example 2 shows the results of crushing using an oval spherical container (see FIG. 14). Comparative Example 2 shows the results of crushing using a spherical container (see FIG. 3).

[0156] [Table 3] Table 3 shows the test conditions for Reference Example 1, Reference Example 2, Reference Example 2-2, and Comparative Example 2. The rotation speed, grinding time, and ball size are common. The container capacity is different because the container shape is different. Therefore, the weight of the material to be ground and the number of balls (weight) are set so that the weight of the material to be ground / the container capacity and the weight of the material to be ground / the ball weight are common.

[0157] [Table 4] Table 4 shows the test results of Reference Example 1, Reference Example 2, Reference Example 2-2, and Comparative Example 2. The grinding effect is evaluated from the particle size distribution and the specific surface area.

[0158] FIG. 20 shows the particle size distributions of Reference Example 1, Reference Example 2, Reference Example 2-2, and Comparative Example 2.

[0159] Comparing Reference Example 1 and Reference Example 2 with Comparative Example 2, the values ​​of Reference Example 1 and Reference Example 2 are clearly smaller (by about one digit) in all the indices of maximum diameter, minimum diameter, volume average diameter MV, d10, d50, and d90, indicating a greater grinding effect. Also, in the index of specific surface area, the values ​​of Reference Example 1 and Reference Example 2 are clearly larger, indicating a greater grinding effect.

[0160] <Alignment> In the prior art, the cross-sectional shape of the spherical container is a perfect circle both in the cross-sectional shape perpendicular to the horizontal axis and in the cross-sectional shape perpendicular to the orthogonal axis. In order to utilize the uniformity of the shape of the spherical container, the inventors of the present application considered it to be preferable that the center of gravity position of the spherical container coincide with the three-dimensional center of rotation position.

[0161] On the other hand, the above results suggest that the change in ball trajectory caused by a non-spherical container is more likely to have a crushing effect than the steady state of the ball trajectory caused by a spherical container. Therefore, it is thought that by shifting the center of gravity and the three-dimensional center of rotation of the container and making them eccentric, more changes will occur and a greater crushing effect can be expected. Therefore, as follows, we will verify the crushing effect with and without eccentricity.

[0162] Reference Example 2-2 is a combination of a semi-elliptical spherical container and a semi-spherical container (not shown). It is essentially an eccentric elliptical spherical container that is asymmetric with respect to the minor axis.

[0163] Comparing Reference Example 2, which is an oval spherical container without eccentricity, with Reference Example 2-2, which is an oval spherical container with eccentricity, the values ​​of Reference Example 2 are smaller in all indicators, including maximum diameter, minimum diameter, volume mean diameter MV, d10, d50, and d90, indicating a greater grinding effect. Also, the value of Reference Example 2 is larger in the indicator of specific surface area, indicating a greater grinding effect. This suggests that it is more preferable for the center of gravity of the container to coincide with the three-dimensional rotation center (no eccentricity). In other words, it suggests that a large trajectory change due to the container shape is more preferable than a very large trajectory change due to eccentricity.

[0164] Among the above-mentioned examples of container shapes, a spherical container, an elliptical sphere, a spindle-shaped sphere, an oval sphere, etc. are symmetrical with respect to the minor axis, making it easy to set the position of the center of gravity of the container. On the other hand, an egg-shaped sphere, a combination of a semi-elliptical sphere and a semi-spindle-shaped sphere and a semi-spindle-shaped sphere and a semi-egg ...

[0165] Therefore, it is preferable to mount the container on the rotating device via a jig 25 (see FIG. 15) that adjusts the positional relationship between the container's center of gravity and the three-dimensional rotation center. Jig 25 connects the container flange and the inner rotating frame 8 in a manner that allows its length to be adjusted. In FIG. 15, the length of jig 25 is 36 mm. This ensures that the positional relationship between the container's center of gravity and the three-dimensional rotation center coincides even for a container that is asymmetric with respect to the minor axis.

[0166] <Supplementary Information> In the present invention, the effect is particularly pronounced when the fine particle size after pulverization is fine (for example, 1 / 100 or less of the hard ball size). In the above reference example, fine particles about 1 / 2500 of the hard ball size are produced.

[0167] On the other hand, for example, by using large, medium and small balls of different sizes, it is possible to deal with the case where the size gradually becomes smaller through crushing (Comparative Example 3) (see FIG. 21). However, in Comparative Example 3, the amount of balls that can be handled is relatively small, and sufficient crushing time is required.

[0168] In contrast, in the present invention, even if balls of the same size are used, the same effect as in Comparative Example 3 can be obtained in a short time. However, as in Comparative Example 3, balls of different sizes, large, medium and small, may be used. [Explanation of symbols]

[0169] 1 Electric motor 2 1st horizontal axis 3 Outer rotating frame 4 Electric motor 5 Second horizontal axis 6 Driven disc 7 Orthogonal Axes 8 Inner rotating frame 9 Driven disc 10 Transmission Mechanism 11 First magnet 12 Second magnet 13 Space 22 Spherical container 23 Oval sphere container 25 Jig 30 Control device 100 Main equipment configuration

Claims

1. A rotating device for rotating a container containing hard balls and a material to be crushed in three dimensions around a horizontal axis and an orthogonal axis to crush the material to be crushed into fine particles having an average diameter of 1 / 100 or less of the average diameter of the hard balls, A reversing mechanism that switches between forward and reverse rotation; A detection means for detecting a three-dimensional rotation state related to the crushing effect suppression state; a switching control device that issues a switching command to the reversing mechanism based on the state information detected by the detection means; have A rotating device characterized by:

2. The detection means detects a current load caused by rotational driving.

2. The rotating device according to claim 1.

3. The detection means detects a sound generated by the rotational drive.

2. The rotating device according to claim 1.

4. The detection means detects the temperature of the container.

2. The rotating device according to claim 1.

5. The detection means detects vibration of the rotating device.

2. The rotating device according to claim 1.

6. The inversion mechanism includes: Inversion around a horizontal axis, inversion around an orthogonal axis, and inversion around both a horizontal axis and an orthogonal axis are possible.

6. The rotating device according to claim 1, wherein the rotating device is a rotating shaft.

7. A first rotary drive device; a first horizontal shaft rotated by the first rotary drive; an outer rotating frame coupled to the first horizontal shaft; a second rotary drive device provided on the opposite side to the first rotary drive device; a second horizontal shaft provided on the opposite side to the first horizontal shaft, passing through one side of the outer rotary frame, and rotated by the second rotary drive device; a driven disk coupled to the second horizontal shaft and having a plate surface perpendicular to the second horizontal shaft; an orthogonal axis having an axis direction perpendicular to an axis direction of the first horizontal axis and the second horizontal axis and provided on the outer rotating frame; an inner rotating frame coupled to the orthogonal shaft and holding the container; A driven disk coupled to the orthogonal axis and having a plate surface in a direction perpendicular to the orthogonal axis; a transmission mechanism for transmitting a rotational force of the driving disk to the driven disk; a control device that individually controls outputs of the first rotary drive device and the second rotary drive device; Equipped 7. The rotating device according to claim 1, wherein the rotating device is a rotating shaft.

8. A rotary drive device; A horizontal shaft rotated by the rotary drive; an outer rotating frame coupled to the horizontal shaft; a driven disk that penetrates one side of the outer rotary frame and is coupled to the horizontal shaft, the driven disk having a plate surface in a direction perpendicular to the horizontal shaft; an orthogonal axis having an axis direction perpendicular to the axis direction of the horizontal axis and provided on the outer rotating frame; an inner rotating frame coupled to the orthogonal shaft and holding the container; A driven disk coupled to the orthogonal axis and having a plate surface in a direction perpendicular to the orthogonal axis; a transmission mechanism that transmits a rotational force around the driving disk to the driven disk; A control device for controlling an output of the rotary drive device; Equipped 7. The rotating device according to claim 1, wherein the rotating device is a rotating shaft.

9. Using the rotating device according to any one of claims 1 to 8, Put hard balls and the material to be crushed into the container, The container is rotated three-dimensionally, for example by rotating it forward and then rotating it backward; The material to be crushed is crushed into fine particles. A method for producing microparticles.

10. The forward and reverse rotations are repeated alternately.

10. The method for producing fine particles according to claim 9.

11. The material to be ground is silicon grains.

11. The method for producing fine particles according to claim 10.

12. The shape of the container is such that one of a first cross section perpendicular to the horizontal axis and a second cross section perpendicular to the perpendicular axis is substantially circular, and the other is substantially elliptical and asymmetric with respect to the minor axis or the major axis.

12. The method for producing fine particles according to claim 9, wherein the fine particles are mixed with the fine particles.

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