JP2021147629A - Stirrer and molten metal processor - Google Patents

Abstract

To save an amount of use of a gas by not staying in a molten metal or aqueous solution, by generating bubbles that have small diameter and to not deteriorate a stirring efficiency in the previous process.SOLUTION: A stirring portion 70 which is attached to a rotary drive shaft 53 and agitates the molten aluminum alloy and supplies treatment gas G is provided with: a cylindrical housing 71 in which the base end side is attached to a bearing portion 54 supporting the rotary drive shaft 53 and the treatment gas G is supplied; a rotary shaft 72 that is inserted into the inside of the housing 71 and the base end side is bonded to the rotary drive shaft 53; a rotary blade 73 provided to an opening end 71a side of the housing 71 and attached to a tip end side of the rotary shaft 72; and an elevator mechanism 60 for moving, by elevating the housing 71, the rotary blade 73 between a position exposed from the opening end 71a side of the housing 71 and a position for storing on the opening end 71a side.SELECTED DRAWING: Figure 4

Description

The present invention relates to a stirrer and a molten metal treatment device used for stirring a liquid substance, for example, a metal such as a molten aluminum alloy or a magnesium alloy, or various aqueous solutions.

Products using aluminum alloys and magnesium alloys may be recovered at the end of the product life, melted in a melting furnace or the like, and reused for other products.

Since aluminum alloys and magnesium alloys are chemically active metals, they are easily oxidized when exposed to the atmosphere in a melting furnace or the like, and a large amount of oxides and inclusions attached to the oxides (hereinafter referred to as "dross"). ) Is formed. In addition to oxides such as _{Al 2} O ₃ , MgO, Al ₂ MgO ₄ , SiO ₂ , silicate, Al · Si · O, FeO, Fe ₂ O _{3 , carbides (Al 4} C ₃ , Al ₄₎ are included in the dross. There are O ₄ C, graphite carbon), boronide (AlB ₂ , AlB ₁₂ , TiB ₂ , VB ₂ ), Al ₃ Ti, Al ₃ Zr, CaSO ₄ , Al N and various halides. When dross is suspended and mixed into the molten aluminum, it eventually becomes a non-metal inclusion and causes deterioration of the quality of products such as wrought products, forged products, and die-cast products. Therefore, it is necessary to separate and remove the dross from the molten metal at each stage of the melting furnace, holding furnace, tribe, etc.

A technique for separating and discharging dross from a molten metal by changing the rotational inclination of the melting furnace and efficiently recovering the dross is disclosed (see, for example, Patent Document 1). In this way, the dross can be efficiently recovered in the dissolution step, but since the molten Al contains an impurity gas component such as hydrogen, it is necessary to further degas at the time of re-dissolution.

On the other hand, as a degassing treatment method, there is known a technique of blowing a treatment gas such as argon, nitrogen, or chlorine into a molten metal in a treatment tank to perform gas bubbling. For example, a method of injecting flux into the molten metal in gas bubbling (see, for example, Patent Document 2) or a method of stirring the molten metal in gas bubbling with a rotary blade (see, for example, Patent Documents 3, 4 and 5). Are known. Further, there is known a method for treating a molten metal in which a flux is added to the molten metal and stirred with a stirrer to modify oxides mixed in the molten metal to easily separate dross from the molten metal (for example, Patent Document 6). reference.).

Japanese Unexamined Patent Publication No. 10-227567 (pages 4 to 5) Japanese Unexamined Patent Publication No. 63-183136 (pages 1 to 4, FIGS. 1, 2) Japanese Unexamined Patent Publication No. 10-306330 (pages 3 to 4, FIGS. 5, 6) Japanese Unexamined Patent Publication No. 62-297422 (page 1, FIG. 1) Gazette No. 7-68591 (page 1, Fig. 1) Japanese Unexamined Patent Publication No. 2004-143483 (FIGS. 1 and 4)

The above-mentioned agitator and molten metal treatment device have the following problems. That is, when the rotary blades were placed near the surface of the molten aluminum in order to improve the stirring efficiency of the molten aluminum, dross and flux, only the bubbles were mixed and the diameter of the bubbles was not sufficiently reduced. For this reason, the surface area per unit volume of the bubble becomes small, and the residence time in the molten metal becomes short, so that the bubble diffuses into the atmosphere in a short time before it sufficiently reacts. Therefore, the supply amount of the processing gas is, for example, about 20 L per minute at 0.3 MPa, and it is necessary to supply about 100 L of the processing gas in a general processing time. For this reason, a large amount of processing gas is used, which causes an increase in processing cost.

It should be noted that the same problem may occur not only with the stirring of the molten metal but also with the aqueous solution.

On the other hand, in order to generate bubbles having a small diameter, if the rotary blade is rotated at a deep position of the molten metal and is rotated inside the housing, there is a problem that the above-mentioned stirring efficiency is lowered.

Therefore, the present invention has been made to solve the above-mentioned problems. By generating bubbles having a small diameter, the amount of gas used can be reduced by staying in a molten metal or an aqueous solution, and in the previous step. An object of the present invention is to provide a stirrer that does not reduce the stirring efficiency and a molten metal treatment apparatus using the stirrer.

The stirrer according to the present embodiment is a stirrer which is attached to a rotary drive shaft to agitate molten metal and supply a processing gas. The base end side is attached to a drive mechanism supporting the rotary drive shaft and the processing gas. A cylindrical housing to which the It is provided with an elevating mechanism that moves the rotary blade attached to the housing and a position where the rotary blade is exposed from the tip side of the housing and a position where the housing is stored in the tip side. ..

The molten metal treatment apparatus according to the present embodiment is a molten metal treatment apparatus that agitates the molten metal and removes unnecessary gas by supplying the processing gas, and supplies the processing tank for accommodating the molten metal and the processing gas. The stirrer is provided with a gas supply mechanism and a stirrer that is detachably provided in the treatment tank. The housing, the rotating shaft inserted inside the housing, and the base end side coupled to the rotating drive shaft, and the rotating blades provided on the tip side of the housing and attached to the tip side of the rotating shaft. The housing is provided with an elevating mechanism for elevating and lowering the housing to move the rotary blades between a position where the rotary blades are exposed from the tip side and a position where the rotary blades are stored on the tip side.

The stirrer according to the present embodiment is a stirrer which is attached to a rotary drive shaft and agitates water or an aqueous solution and supplies a processing gas. A tubular housing to which gas is supplied, a rotation shaft inserted inside the housing and having a base end side coupled to the rotation drive shaft, and a tip end side of the rotation shaft provided on the tip side of the housing. It is provided with a rotary blade attached to the side and an elevating mechanism for raising and lowering the housing to move the rotary blade between a position where the rotary blade is exposed from the tip side of the housing and a position where the rotary blade is stored on the tip side. There is.

By generating a bubble having a small diameter, it is possible to reduce the amount of gas used by staying in the molten metal or the aqueous solution for a long time and not to reduce the stirring efficiency in the previous step.

The explanatory view which shows the degassing treatment apparatus which incorporated the stirrer which concerns on one Embodiment of this invention. The perspective view which shows the rotary vane incorporated in the degassing processing apparatus. Explanatory drawing which shows the degassing treatment process by the degassing treatment apparatus. The vertical sectional view which shows the operation of the stirrer. The vertical sectional view which shows the operation of the stirrer.

FIG. 1 is a diagram showing a degassing treatment device (molten metal treatment device) 10 in which the stirring device 40 according to the embodiment of the present invention is incorporated. As shown in FIG. 1, the degassing treatment device 10 is detachably suspended from the treatment tank 20, the gas supply / rotation drive mechanism 30 arranged in the vicinity of the treatment tank 20, and the gas supply / rotation drive mechanism 30. It includes a lowered stirring device 40, a flux charging device 100 and a dross removing device 110 arranged in the vicinity of the processing tank 20.

The treatment tank 20 is made of a refractory material and has a treatment capacity capable of degassing up to 1500 kg of molten aluminum per batch.

The flux charging device 100 has a function of charging the flux F into the molten aluminum P in the processing tank 20. The flux charging device 100 has a plurality of hoppers, shooters, etc. containing an aluminum scavenger as the flux F, and a predetermined amount of the aluminum scavenger of a predetermined component is blended in a predetermined blending ratio in the treatment tank 20. It has a function to put it in. The flux F may be mixed with the processing gas G described later as a flux gas and supplied from the gas supply / rotation drive mechanism 30.

The dross removing device 110 includes a scraping jig and a suction / discharging device. The scraping jig is made of plate-shaped carbon, refractory material, and ceramic member, and its surface is specially processed so that dross does not adhere. The suction / discharge device has a trumpet-shaped suction port made of a heat-resistant material, and communicates with the collection pot via a suction pump.

A melting furnace 200 is arranged adjacent to the treatment tank 20, and the molten aluminum is poured into the treatment tank 20 from the melting furnace 200 in a non-oxidizing atmosphere. The melting furnace has a dross separation / removal function, and a large amount of dross is separated from the molten metal and removed in the melting furnace.

The gas supply / rotation drive mechanism 30 includes a gantry 31, a post 32 extending vertically on the gantry 31 and swinging along an axis in the vertical direction, and an endless belt arranged along the post 32. A 33, a slider 34 attached to the endless belt 33, and a drive motor 35 for driving the endless belt 33 are provided. A cylinder drive gas supply unit 36 for supplying compressed air for driving the gas cylinder 66 and a gas supply unit 37 for supplying the processing gas G are arranged in the gantry 31. The cylinder drive gas supply unit 36 is connected to one end side of the air supply line 46 described later, and the gas supply unit 37 is connected to one end side of the gas supply line 47 described later.

An arm 39 is attached to the slider 34 in the horizontal direction, and a stirring device 40 is provided at the tip thereof. Therefore, the arm 39 can be swiveled and lifted by the post 32.

The stirring device 40 includes a rotation driving unit 50 suspended from an arm 39, an elevating mechanism 60, and a stirring unit 70.

The rotary drive unit 50 includes a rotary drive motor 51, a rotary drive shaft 53 attached to the rotary drive motor 51 via a coupling 52, and a bearing portion 54 that rotatably supports the rotary drive shaft 53. .. The rotary drive shaft 53 extends in the vertical direction. Further, the bearing portion 54 is attached to a support column 64, which will be described later. A rotary shaft 72 of a stirring unit 70, which will be described later, is detachably attached to the tip of the rotary drive shaft 53.

The elevating mechanism 60 includes an upper pedestal 61 that supports the lower part of the rotary drive motor 51, an intermediate pedestal 62 provided below the upper pedestal 61, and a lower pedestal 63 further below the intermediate pedestal 62.
A support column 64 is arranged between the upper pedestal 61 and the middle pedestal 62 to maintain a constant interval. Further, a bellows 65 that airtightly encloses the above-mentioned rotary drive shaft 53 is arranged between the middle pedestal 62 and the lower pedestal 63, and the interval in the vertical direction in FIG. 1 can be adjusted within a predetermined range. There is.

The lower end of the gas cylinder 66 is attached to the middle frame 62. The piston 67 of the gas cylinder 66 penetrates the middle pedestal 62, and its tip is attached to the lower pedestal 63. By the operation of the gas cylinder 66, the distance between the middle pedestal 62 and the lower pedestal 63 is adjusted. The middle pedestal 62 and the lower pedestal 63 are airtightly closed by a bellows 65. The other end side of the air supply line 46 is connected to the gas cylinder 66, and by supplying compressed air to the gas cylinder 66, the piston 67 is projected downward and the lower pedestal 63 is attached to the middle pedestal 62. Move relatively downward.

A gas injection port 62a communicating with the inside of the bellows 65 is formed in the upper part of the bellows 65. The other end side of the gas supply line 47 is connected to the gas injection port 62a, and the processing gas G is supplied from the gas supply unit 37 described above. The processing gas G is, for example, a non-oxidizing gas such as argon gas or nitrogen gas. Flux gas may be mixed as described above. The processing gas G is supplied into the housing 71, which will be described later, through the inside of the bellows 65. The supply of the processing gas G has the effect of cooling the heat received from the molten aluminum P and preventing the temperature of each component from rising.

The stirring unit 70 includes a cylindrical housing 71 that is airtightly attached to the lower surface of the lower pedestal 63, and a rotating shaft 72 that is inserted inside the housing 71 and whose base end side is coupled to the rotating drive shaft 53. There is. Inside the housing 71, a rotary blade 73 attached to the tip end side of the rotary shaft 72 is arranged. A plurality of oval-shaped openings 74 are formed on the base end side of the housing 71 from the position of the rotary blade 73. The size and number of openings 74 may be appropriately changed depending on the type of molten metal. Since the stirring unit 70 is immersed in the molten aluminum P, it is made of a heat-resistant ceramic material or carbon material.

A sufficient space is provided between the housing 71 and the rotating shaft 72, and the processing gas G is supplied to the periphery of the rotating blade 73 through this space.

As shown in FIG. 2, the rotary blade 73 has three blades 73a arranged side by side in the axial direction. The blades 73a are separated from each other in the axial direction of the rotating shaft 72, and a gap S is formed. The outer peripheral surface of each blade 73a is formed close to the inner wall of the housing 71, and its dimensions are set to, for example, about 3 mm to 10 mm. The spiral surface 73b of each blade 73a is formed downward to the right.

Further, the rotary blade 73 is preferably made of a ceramic material so as not to be melted by the heat of the molten aluminum P. Since it is difficult for a ceramic material to form a complicated shape by itself, by arranging the blades 73a in parallel in the axial direction as described above, a complicated blade shape like a metal blade can be virtually realized. , Microbubbles, stirring power, transmission and output, etc. are ensured. In addition, the characteristics of the rotary blade 73 can be adjusted by the arrangement, shape, number, spacing, arrangement of the spiral surface 73b, and the like of the blades 73a.

Next, the degassing treatment method by the degassing treatment apparatus 10 according to the present embodiment will be described with reference to FIGS. 3 to 5. In addition, R in FIGS. 4 and 5 indicates a rotation direction. In the stirring device 40, the gas cylinder 66 is operated to bring the middle pedestal 62 and the lower pedestal 63 close to each other. As a result, the rotary blade 73 projects downward from the open end 71a of the housing 71. After melting the aluminum in the melting furnace 200, the molten aluminum P is transferred from the melting furnace to the processing tank 20 together with the dross D (step S1). Next, the flux F of a predetermined component is put into the processing tank 20, the stirring device 40 is lowered, and the rotary blade 73 is immersed just below the surface of the molten aluminum P in the processing tank 20. Then, the rotary blade 73 is rotated at, for example, 400 rpm, and the molten aluminum P, the dross D, and the flux F are stirred for several minutes. As a result, the dross D is modified and separated from the molten aluminum P (step S2).

Next, in the stirring device 40, the gas cylinder 66 is operated to separate the middle pedestal 62 and the lower pedestal 63. As a result, the rotary blade 73 is housed inside from the open end 71a of the housing 71. Further, the stirring device 40 is further lowered. The opening end 71a side of the housing 71 of the stirring unit 70 is positioned near the bottom of the processing tank 20, and the rotary blade 73 is rotated at, for example, 1000 rpm. By the action of the rotary blade 73, as shown in FIG. 5, the molten aluminum P in the vicinity of the opening 74 is drawn downward into the housing 71 and circulates while being sent downward from the opening end 71a of the housing 71.

Further, the processing gas G supplied from the cylinder drive gas supply unit 36 enters the housing 71, which has a negative pressure due to the action of the rotation of the rotary blade 73, and becomes a bubble having a relatively large diameter to form a bubble with the rotary blade 73. It enters the gap in the housing 71. At this time, the bubbles move in and out of the gap S to repeat compression and expansion. In this process, the bubbles are crushed into small-diameter bubbles and bubbles. In this way, microbubbles (diameter: several μm to 50 μm) are formed by the shearing action of the rotary blade 73. As a result, when the processing gas G is supplied and diffused in the molten aluminum P (gas bubbling), impurity gas components such as dross D and hydrogen mixed in the molten aluminum P float on the surface of the molten aluminum (step S3). The stirring force at this time shall be weak enough not to inhibit the gas bubbling reaction. After continuing the gas bubbling for several minutes, the gas blowing is stopped and the degassing process is completed.

Next, the dross removing device 110 is lowered, the lower portion thereof is immersed in the molten metal surface, and the dross D is gathered at a specific location in the processing tank 20 (step S4). The collected dross D is sucked and discharged from the processing tank 20 by a suction and discharge device, and collected in a recovery pot (step S5).

As described above, according to the stirring device 40 and the degassing treatment device 10 according to the present embodiment, microbubbles are generated by compressing, expanding, and shearing the processing gas G in the gap between the rotary blade 73 and the housing 71. Can be made to. For this reason, the surface area of the treated gas in the molten metal is increased to facilitate the reaction with the dissolved hydrogen gas, and by staying in the molten metal for a long time, the reaction time with the hydrogen gas is extended, which is sufficient. Hydrogen gas can be removed. Further, since an opening 74 for sucking an amount of molten metal corresponding to the negative pressure accompanying the rotation of the rotary blade 73 is formed on the side surface of the housing 71 accommodating the rotary blade 73, a vortex is formed on the surface of the molten metal. Can be prevented from being formed, and it is possible to prevent the formation of oxides by entraining the atmosphere. That is, it is possible to release the microbubbled processing gas, suppress excessive stirring of the molten metal, and promote the dispersion of the processing gas. Therefore, degassing can be sufficiently performed, and a high quality aluminum alloy can be obtained.

Although aluminum alloys have been exemplified as the above-mentioned metals, they can also be applied to molten metal of other metals such as magnesium alloys. Further, in addition to the molten metal, in water, an aqueous solution, etc., the reaction efficiency of the processing gas into the liquid can be improved and the reaction time can be extended by using microbubbles having a diameter of about several μm to 50 μm. It can save the amount of processing gas.

In addition, the rotation direction and rotation speed of the rotation shaft 72, and the position, number, size, and shape of the openings 74 are not limited to those described above, and may be appropriately changed depending on the stirring target and the physical characteristics of the gas. ..

The present invention is not limited to the above embodiment, and can be variously modified at the implementation stage without departing from the gist thereof. In addition, each embodiment may be carried out in combination as appropriate, and in that case, the combined effect can be obtained. Further, the above-described embodiment includes various inventions, and various inventions can be extracted by a combination selected from a plurality of disclosed constituent requirements. For example, even if some constituent requirements are deleted from all the constituent requirements shown in the embodiment, if the problem can be solved and the effect is obtained, the configuration in which the constituent requirements are deleted can be extracted as an invention.

10 ... Degassing treatment device (molten metal treatment device), 20 ... Treatment tank, 30 ... Rotational drive mechanism, 31 ... Stand, 32 ... Post, 33 ... Endless belt, 34 ... Slider, 35 ... Drive motor, 36 ... Cylinder drive gas Supply unit, 37 ... Gas supply unit, 39 ... Arm, 40 ... Stirrer, 46 ... Air supply line, 47 ... Gas supply line, 50 ... Rotation drive unit, 51 ... Rotation drive motor, 52 ... Coupling, 53 ... Rotation Drive shaft, 54 ... Bearing part, 60 ... Elevating mechanism, 61 ... Upper stand, 62 ... Middle stand, 63 ... Lower stand, 64 ... Support, 65 ... Bellows, 66 ... Gas cylinder, 67 ... Piston, 70 ... Stirring part, 71 ... Housing, 71a ... Open end, 72 ... Rotating shaft, 73 ... Rotating blade, 73a ... Blade, 73b ... Spiral surface, 74 ... Opening, 100 ... Flux injection device, 110 ... Dross removing device, 200 ... Melting furnace ..

Claims (4)

In a stirrer attached to a rotary drive shaft that agitates molten metal and supplies processing gas.
A cylindrical housing whose base end side is attached to a drive mechanism that supports the rotary drive shaft and to which the processing gas is supplied.
A rotary shaft that is inserted inside the housing and whose base end side is coupled to the rotary drive shaft.
Rotating blades provided on the tip side of the housing and attached to the tip side of the rotating shaft,
A stirrer including an elevating mechanism for elevating and lowering the housing to move the rotary blade between a position where the rotary blade is exposed from the tip side and a position where the rotary blade is stored on the tip side. The stirrer according to claim 1, further comprising an opening formed on the outer surface of the housing. In a molten metal treatment device that agitates molten metal and removes unnecessary gas by supplying treatment gas.
A treatment tank for accommodating the molten metal and
The gas supply mechanism that supplies the processing gas and
The processing tank is equipped with a removable stirrer.
The stirrer has a cylindrical housing whose base end side is attached to a drive mechanism that supports a rotary drive shaft and to which the processing gas is supplied.
A rotary shaft that is inserted inside the housing and whose base end side is coupled to the rotary drive shaft.
Rotating blades provided on the tip side of the housing and attached to the tip side of the rotating shaft,
A molten metal processing apparatus including a elevating mechanism for raising and lowering the housing to move the rotary blade between a position where the rotary blade is exposed from the tip side and a position where the rotary blade is stored on the tip side. In a stirrer attached to a rotary drive shaft that agitates water or an aqueous solution and supplies a processing gas.
A cylindrical housing whose base end side is attached to a drive mechanism that supports the rotary drive shaft and to which the processing gas is supplied.
A rotary shaft that is inserted inside the housing and whose base end side is coupled to the rotary drive shaft.
Rotating blades provided on the tip side of the housing and attached to the tip side of the rotating shaft,
A stirrer including an elevating mechanism for elevating and lowering the housing to move the rotary blade between a position where the rotary blade is exposed from the tip side and a position where the rotary blade is stored on the tip side.

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