JP4988331B2 - Aluminum purification method and apparatus - Google Patents

Description

  The present invention relates to an aluminum refining method and apparatus for obtaining high-purity aluminum = um used for aluminum materials for electrolytic capacitors, conductive materials, aircraft materials, and the like, and an aluminum lump.

Impurities in the aluminum, Fe in particular generating a Aluminum and eutectic, Si, if it contains impurities such as Cu, in order to obtain a high purity aluminum by removing these impurities, the aluminum melted, the principle that the primary crystal aluminum be selectively taken out is effective when solidifying it by cooling is well known.

  Conventionally, various aluminum purification methods using the above principle have been proposed. For example, in Patent Document 1, as shown in FIG. 2, the relative speed between the molten aluminum 2 accommodated in the furnace body 1 and the outer peripheral portion of the cooling body 3 immersed in the molten aluminum 2 is 1600 to 8000 mm / sec. It has been proposed to rotate the cooling body 3 so that the concentrated layer of impurities in the vicinity of the solidification interface is thinned and the purity of the purified aluminum 5 is increased.

Further, in Patent Document 2, the molten aluminum is rotated so that the centrifugal acceleration acting on the molten aluminum around the cooling body is 0.01 m / s ² or more and 1500 m / s ² or less, and gas bubbles are introduced. Impurities are concentrated at the solidification interface by introducing into the molten aluminum and moving the gas bubbles to the solidification interface by the reaction force of the centrifugal force acting on the molten aluminum, and passing through the solidification interface and its vicinity while floating. Means have been proposed that can efficiently remove the layer.
Japanese Patent Publication No.61-3385 Japanese Patent No. 3673322

  However, in these conventional techniques, the impurities of the obtained aluminum cannot be sufficiently removed, and there are operational problems.

  That is, in the method as described in Patent Document 1, since molten aluminum also flows in the same direction as the cooling body rotates, there is a limit to thinning the impurity concentration layer, and in order to obtain high purification efficiency. To. When the rotational speed of the cooling body is made too fast, there is a problem that the purified aluminum that has grown on the cooling body is peeled off, and the molten aluminum is likely to jump and fly.

  Further, in the method as described in Patent Document 2, there is no means for efficiently rotating the molten aluminum, it is difficult to obtain a high rotation speed, and gas bubbles are introduced, and the solidification interface is rubbed and concentrated. Even if the layer is made thin, the effect is limited, and there is a problem that high purification efficiency cannot be obtained.

The present invention has been made in view of such circumstances, purification efficiency is high, are intended to be subjected Hisage purification method and apparatus for purifying aluminum having no workability problems splashing or jump like the molten aluminum .

  As a result of diligent studies to overcome the problems of the prior art as described above, the present inventors have found a purification method and a purification device that have high purification efficiency and good workability without splashing or jumping of molten aluminum.

That is, the said subject is solved by the following means.
(1) In a method of refining aluminum in which a cooling body is immersed in molten aluminum that exceeds the solidification temperature, and aluminum is crystallized and grown on the surface of the cooling body, the cooling body is rotated in one direction and simultaneously melted. A method for purifying aluminum, characterized in that high-purity aluminum is crystallized on the surface of a cooling body while applying a rotational force in a direction opposite to the rotational direction of the cooling body to the aluminum.
(2) The method for purifying aluminum as described in (1) above, wherein the rotational force on the molten aluminum is applied by an electromagnetic rotating magnetic field.
(3) The method for purifying aluminum as described in (1) above, wherein the rotational force for molten aluminum is applied by mechanical rotational force.
(4) The method for purifying aluminum as described in (1) above, wherein the rotational force with respect to the molten aluminum is applied by a rotating magnetic field by a permanent magnet.
(5) The magnitude of the rotational force applied to the molten aluminum is converted into the case of rotating the molten aluminum alone, and the rotational speed is any one of the preceding items 1 to 4 corresponding to 200 to 5000 mm / sec. The method for purifying aluminum as described.
(6) The method for purifying aluminum as described in any one of 1 to 5 above, wherein the rotational speed of the cooling body is in the range of 1500 to 8000 mm / sec.
(7) A furnace body that contains molten aluminum that exceeds the solidification temperature, a rotatable cooling body that is immersed in the molten aluminum housed in the furnace body, and a molten aluminum housed in the furnace body And a rotational force applying device for applying a rotational force in a direction opposite to the rotational direction of the cooling body.
(8) The apparatus for purifying aluminum as described in (7) above, wherein the rotational force applying device uses an electromagnetic rotating magnetic field.
(9) The aluminum refining device according to item 7 above, wherein the rotational force applying device uses mechanical rotational force.
(10) The aluminum refining device according to (7), wherein the rotational force applying device uses a rotating magnetic field by a permanent magnet.
(11) The magnitude of the rotational force imparted to the molten aluminum by the rotational force imparting device is calculated in the case of rotating the molten aluminum alone, and the rotational speed is equivalent to 200 to 5000 mm / sec. The apparatus for purifying aluminum according to any one of 10 to 10.
(12) The aluminum purifier according to any one of items 7 to 11 above, wherein the rotational speed of the cooling body is in the range of 1500 to 8000 mm / sec.

  According to the invention described in item (1) above, the cooling body is rotated in one direction, and at the same time a rotational force in the direction opposite to the rotation direction of the cooling body is applied to the molten aluminum. The relative speed of aluminum can be increased, and high purification efficiency can be obtained. In addition, since the rotation of the molten aluminum is moderately apparent, the surface of the molten metal during refining is gentle, the molten metal is less likely to splash and scatter, and the workability is good. Furthermore, since it is not necessary to make the rotational speed of the cooling body faster than necessary, this also stabilizes the molten metal surface during refining and contributes to the suppression of splashing and scattering of molten aluminum.

  According to the invention described in the preceding item (2), a rotating force in a direction opposite to the cooling body can be applied to the molten aluminum by using a rotating magnetic field by an electromagnet.

  According to the invention described in the preceding item (3), for example, by utilizing a mechanical rotational force such as rotation of a furnace body containing a stirrer or molten aluminum, the molten aluminum is in a direction opposite to the cooling body. A rotational force can be applied.

  According to the invention described in item (4) above, it is possible to apply a rotational force in a direction opposite to the cooling body to the molten aluminum using a rotating magnetic field by a permanent magnet.

  According to the invention described in item (5) above, it is possible to obtain a sufficient refining efficiency by obtaining a sufficient relative speed with the cooling body while suppressing splashing and scattering of molten aluminum.

  According to the invention described in the preceding item (6), it is possible to obtain a sufficient relative speed with the cooling body and to obtain high purification efficiency while suppressing the jumping and scattering of the molten aluminum.

  According to the invention described in item (7), the purifier is capable of rotating the cooling body in one direction and simultaneously applying a rotational force in a direction opposite to the rotating direction of the cooling body to the molten aluminum. However, by using this apparatus, it is possible to increase the relative speed of the cooling body and the molten aluminum, and high purification efficiency can be obtained.

  According to the invention described in the preceding item (8), the rotational force in the direction opposite to the cooling body can be applied to the molten aluminum by the rotational force applying device using the rotating magnetic field by the electromagnet.

  According to the invention described in the preceding item (9), for example, with a rotational force imparting device using mechanical rotational force such as rotation of a furnace body containing a stirrer or molten aluminum, Can apply a rotational force in the opposite direction.

  According to the invention described in the preceding item (10), the rotational force in the direction opposite to the cooling body can be applied to the molten aluminum by the rotational force applying device using the rotating magnetic field by the permanent magnet.

  According to the invention described in the preceding item (11), it is possible to obtain a sufficient relative speed with the cooling body and obtain high purification efficiency while suppressing the jumping and scattering of the molten aluminum.

  According to the invention described in the preceding item (12), it is possible to obtain a sufficient relative speed with the cooling body and obtain high purification efficiency while suppressing the jumping and scattering of the molten aluminum.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  1A to 1C are cross-sectional views showing a schematic configuration of an aluminum refining device according to an embodiment of the present invention.

  1 (a) to 1 (c), reference numeral 1 denotes a furnace body. Inside the furnace body 1, molten aluminum (also referred to as a molten metal) 2 exceeding the solidification temperature is accommodated.

  A cooling body 3 is immersed in the molten aluminum 2. The cooling body 3 is rotationally driven in the direction of arrow A via a drive shaft 4 connected to a motor (not shown) during purification. In FIG. 1, reference numeral 5 denotes purified aluminum crystallized on the surface of the cooling body.

  Further, in this embodiment, purification is performed in a state in which a rotational force in the direction opposite to the rotational direction of the cooling body 3 is applied to the molten aluminum 2 as indicated by an arrow B.

  In this way, by applying a rotational force in the opposite direction to the cooling body 3 to the molten aluminum 2, it becomes possible to increase the relative speed of the cooling body 3 and the molten aluminum 2, and high purification efficiency is obtained. It is done. In addition, since the molten aluminum 2 appears to rotate gently, the molten metal surface during refining is gentle, and the molten aluminum 2 is less likely to splash or scatter, and the workability is good. Since it is not necessary to make the rotational speed of the cooling body 3 faster than necessary, this also stabilizes the hot water surface during refining and contributes to the suppression of splashing and scattering of the molten aluminum 2.

  Applying a rotational force in the direction opposite to the rotational direction of the cooling body 3 to the molten aluminum 2 is effective in improving the relative speed between the cooling body 3 and the molten aluminum 2 and thinning the concentrated layer at the solidification interface. There is. The magnitude of the rotational force in the direction opposite to the cooling body 3 applied to the molten aluminum 2 is equivalent to a rotational speed of 200 to 5000 mm / sec in terms of the rotation of the molten aluminum 3 alone. If the rotational speed is less than 200 mm / sec, a sufficient relative speed with the cooling body 3 may not be obtained. If the rotational speed exceeds 5000 mm / sec, the molten aluminum 2 is likely to jump or scatter, which is not preferable. A particularly desirable magnitude of the rotational force is equivalent to a rotational speed of 400 to 4000 mm / sec in terms of rotating molten aluminum 3 alone.

  For example, the following method can be used to identify the rotational speed of the molten aluminum 2 alone.

That is, when the holding surface of the molten aluminum 2 to 670 ° C., floated float having the same diameter as the cooling body 3 at a density 2.0 g / cm ^3, rotates the molten aluminum 2 in the permanent magnet of the molten metal stirring device The rotational speed of the float may be measured. Since the density of the float is smaller than the molten aluminum 2, the rotational speed of the molten aluminum 2 can be estimated almost accurately.

  The cooling body 3 is preferably rotated at a rotational speed of 1500 to 8000 mm / sec. If the rotational speed is less than 1500 mm / sec, a sufficient relative speed between the cooling body 3 and the molten aluminum 2 may not be obtained, and if the rotational speed exceeds 8000 mm / sec, the molten aluminum 2 is likely to jump or scatter, which is preferable. Absent. A particularly desirable rotation speed of the cooling body 3 is 3000 to 6500 mm / sec.

  Examples of the cooling means for the cooling body 3 include flowing air and water into the cooling body and bringing them into contact with each other, but any means can be adopted.

  In this embodiment, the means for rotating the molten aluminum 2 is not limited, and a means for obtaining a desired rotational force can be arbitrarily employed.

  For example, as shown in FIG. 1A, an electromagnetic coil 11 may be disposed around the outer periphery of the furnace body, and a rotating magnetic field may be generated by the electromagnetic coil 11 to apply a rotational force to the molten aluminum 2.

  Further, as shown in FIG. 1B, a mechanical rotational force may be applied to the molten aluminum 2. In the example of FIG. 1B, a stirrer 12 made of stirring blades is disposed inside the molten aluminum 2 at a position below the cooling body 3, and a drive shaft 13 that vertically penetrates the bottom wall of the furnace body 1 is provided. The stirrer 12 is connected to the stirrer 12, and the drive shaft 13 is rotationally driven by a motor or the like (not shown) to rotate the stirrer 12 in the molten aluminum 2 to apply a rotational force. Although not shown in the figure, molten aluminum is produced by utilizing the frictional force acting between the furnace body 1 and the molten aluminum 2 by rotating the furnace body 1 itself in the direction opposite to the rotation direction of the cooling body 3. It is good also as a structure which provides rotational force to 2.

  Moreover, as shown in FIG.1 (c), you may provide the rotational force with respect to the molten aluminum 2 by generating a rotating magnetic field using a permanent magnet. In the example of FIG. 1C, the moving magnetic field generator 14 is disposed below the bottom of the furnace body 1. Permanent magnets 16 having penetrating magnetic field lines penetrating the molten aluminum 2 in the furnace are spaced apart from the rotating plate 15 of the moving magnetic field generator 14, and the rotating plate is driven by a motor or the like via a drive shaft 17 connected to the rotating plate 15. 15 is driven to rotate, and the permanent magnet 16 is rotated in a horizontal plane, thereby generating a rotating magnetic field, thereby providing a mechanism for applying a rotational force to the molten aluminum 2.

  Any method may be used, but a permanent magnet type molten metal stirring device is most suitable. In the case of using an electromagnetic rotating magnetic field that has been often used as a means for moving molten metal, the rotating device becomes large and difficult to reduce in size. However, in the permanent magnet type stirring device, the device is small and handled. It is easy to obtain the desired rotational speed of the molten aluminum 2.

  Molten aluminum containing Fe: 500 ppm and Si: 400 ppm is prepared and heated and maintained at 670 ° C. by a heater. The cooling body 3 was rotated while supplying a cooling fluid into the hollow rotary cooling body 3 having an outer diameter of the upper end of 150 mm and an outer diameter of the lower end of 100 mm. The rotational speed of the cooling body 3 was set as shown in Table 1. At the same time, a rotating force in the direction opposite to the rotating direction of the cooling body 3 was applied to the molten aluminum 2 using a permanent magnet type stirring device as shown in FIG. The rotational force applied at this time was set as shown in Table 1 in terms of the rotational speed when rotating molten aluminum alone.

  When such an operation was performed for 7 minutes, about 6.0 kg of purified aluminum lump was formed on the peripheral surface of the cooling body 3.

  As described above, several experiments were performed by changing the rotational speed of the cooling body and the rotational force in the direction opposite to the cooling body applied to the molten aluminum. Table 1 shows the average impurity concentration and effective distribution coefficient (concentration in refined aluminum / concentration in molten aluminum before purification) of the obtained aluminum ingot.

  As is clear from Table 1, Examples 1 to 1 were performed by applying a rotational force in the opposite direction to the rotation of the cooling body 3 to the molten aluminum 2 simultaneously with the rotation of the cooling body 3 as in the present invention. Compared with Comparative Example 1 and Comparative Example 2 in which no rotational force was applied to molten aluminum 2, No. 5 had good refining efficiency and suppressed the splashing and scattering of the molten metal.

  Moreover, among Examples 1-5, since the rotational force given to the molten aluminum 2 is a little small in Example 2, compared with Example 3 with the same rotation speed of the cooling body 3, refining efficiency is a little inferior. Met. In addition, Example 6 in which the rotational force applied to the molten aluminum 2 was slightly large had good purification efficiency, but some molten aluminum jumped and scattered.

(A)-(c) is sectional drawing which shows schematic structure of the aluminum refinement | purification apparatus which concerns on one Embodiment of this invention. It is sectional drawing which shows schematic structure of the conventional aluminum refinement | purification apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Furnace body 2 Molten aluminum 3 Cooling body 5 Refined aluminum 11 Electromagnetic coil 12 Stirrer 16 Permanent magnet

Claims (12)

In a purification method of aluminum in which a cooling body is immersed in molten aluminum exceeding the solidification temperature, and aluminum is crystallized and grown on the surface of the cooling body.
The high-purity aluminum is crystallized on the surface of the cooling body while rotating the cooling body in one direction and simultaneously applying a rotational force in the direction opposite to the rotation direction of the cooling body to the molten aluminum. To refine aluminum.   The method for purifying aluminum according to claim 1, wherein the rotational force on the molten aluminum is applied by a rotating magnetic field by an electromagnetic method.   The method for purifying aluminum according to claim 1, wherein the rotational force with respect to the molten aluminum is applied by a mechanical rotational force.   The method for purifying aluminum according to claim 1, wherein the rotational force on the molten aluminum is applied by a rotating magnetic field by a permanent magnet.   The magnitude | size of the rotational force provided with respect to molten aluminum is converted into the case where a molten aluminum is rotated alone, and is equivalent to a rotational speed: 200 to 5000 mm / sec. Aluminum purification method.   The method for purifying aluminum according to any one of claims 1 to 5, wherein the rotational speed of the cooling body is in the range of 1500 to 8000 mm / sec. A furnace body containing molten aluminum exceeding the solidification temperature;
A rotatable cooling body immersed in molten aluminum contained in the furnace body;
A rotational force applying device for applying a rotational force in a direction opposite to the rotational direction of the cooling body to the molten aluminum contained in the furnace body;
An apparatus for purifying aluminum, comprising:   The aluminum refining device according to claim 7, wherein the rotational force applying device uses an electromagnetic rotating magnetic field.   The apparatus for purifying aluminum according to claim 7, wherein the rotational force applying device uses mechanical rotational force.   The apparatus for purifying aluminum according to claim 7, wherein the rotational force applying device uses a rotating magnetic field by a permanent magnet.   The magnitude of the rotational force imparted to the molten aluminum by the rotational force imparting device is equivalent to a rotational speed of 200 to 5000 mm / sec in terms of rotating the molten aluminum alone. The apparatus for purifying aluminum according to any one of the above.   The aluminum purifier according to any one of claims 7 to 11, wherein the rotational speed of the cooling body is in the range of 1500 to 8000 mm / sec.

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