JP2018178205A - Agitator and molten metal processor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase a surface area in molten metal and a solution, by generating microbubbles, and achieve retention in the molten metal or a solution for a long period.SOLUTION: In an agitator 50 which is attached to a rotary drive shaft 43, agitates a molten aluminum alloy and supplies a process gas G, there are provided: a cylindrical first housing 51 whose base end side is attached to a tip side of the rotary drive shaft 43 and to which the process gas G is supplied; a rotary shaft 52 which is inserted into the first housing 51, and whose base end side is coupled to the rotary drive shaft 43; a bottomed cylindrical second housing 53 whose inner and outer diameters are larger than those of the first housing 51, whose bottom side is on the first housing 51 side at the tip side of the first housing 51, and which pivotally supports a tip side of the rotary shaft 52; and a rotary blade 54 which is stored in the second housing 53, and attached to the tip side of the rotary shaft 52. A bottom part 53a of the second housing 53 has thereon, an open hole 53b communicated with inside, and a supply hole 53c for supplying the process gas G from an outer periphery of the rotary shaft 52.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a stirrer and a melt processing apparatus used when stirring a liquid substance, for example, a metal such as a molten aluminum alloy or magnesium alloy, various aqueous solutions, and the like.

  Products using aluminum alloy or magnesium alloy may be recovered at the end of the product life, melted in a melting furnace or the like, and reused in 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 etc. and contain oxides attached to large amounts of oxides and oxides (hereinafter referred to as "dross") Form). In addition to oxides such as Al ₂ O ₃ , MgO, Al ₂ MgO ₄ , SiO ₂ , silicates, Al · Si · O, FeO, Fe ₂ O ₃ , carbides (Al ₄ C ₃ , Al ₄₎ There are O ₄ C, graphite carbon), borides (AlB ₂ , AlB ₁₂ , TiB ₂ , VB ₂ ), Al ₃ Ti, Al ₃ Zr, CaSO ₄ , AlN and various halides. When dross is mixed in the molten aluminum due to suspension, it eventually becomes non-metallic inclusions and causes the quality deterioration of products such as wrought materials, forged products, and die cast products. For this reason, it is necessary to separate and remove the dross from the molten metal at each stage of the melting furnace, the holding furnace, the tribe and the like.

  A technique for separating and discharging dross from molten metal by changing the rotational inclination of the melting furnace for efficient recovery is disclosed (for example, see Patent Document 1). As described above, the dross can be efficiently recovered in the melting step, but since the Al molten metal contains an impurity gas component such as oxygen, it is necessary to further carry out the degassing treatment at the time of remelting.

  On the other hand, as a degassing method, a technique is known in which a processing gas such as argon, nitrogen, chlorine or the like is blown into a molten metal in a processing tank to bubbling gas. For example, a method of introducing a flux into molten metal in gas bubbling (see, for example, Patent Document 2) or a method of stirring a molten metal in gas bubbling with a rotating blade (see, for example, Patent Documents 3, 4 and 5) Are known. Furthermore, there is known a method of treating a molten metal in which flux is introduced into the molten metal, the mixture is stirred by a stirrer, and oxides mixed in the molten metal are reformed to easily separate dross from the molten metal (for example, Patent Document 6) reference.).

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

  The stirrer and the melt processing apparatus described above have the following problems. That is, the diameter of the bubble was increased, the surface area per unit volume was decreased, and the residence time in the molten metal was short and diffused in the air in a short time. For this reason, 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 the processing gas of about 100 L in a general processing time. For this reason, the amount of processing gas used is large, which causes the processing cost to be high.

  In addition, when the rotary vanes are disposed near the surface of the molten metal so as to efficiently generate bubbles, large vortices are generated on the surface of the molten metal and the atmosphere is entrained, resulting in an increase in oxides.

  Therefore, the present invention has been made to solve the above-mentioned problems, and by generating microbubbles, the surface area in a molten metal or an aqueous solution is increased, and staying in the molten metal or an aqueous solution for a long time It is an object of the present invention to provide an agitator capable of producing a molten metal and an apparatus for treating molten metal using the agitator.

  In a stirrer attached to a rotary drive shaft for stirring molten metal and supplying a processing gas, a tubular first casing has a base end side mounted on the tip end side of the rotary drive shaft and to which the processing gas is supplied An inner diameter and an outer diameter larger than an inner diameter and an outer diameter of the first housing, the rotation shaft being inserted into the first housing and having the base end side coupled to the rotation drive shaft; A bottomed cylindrical second housing is provided on the tip end side of the first housing with the bottom side facing the first housing side and supports the tip end side of the rotation shaft, and is accommodated in the second housing A rotary blade attached to the tip end side of the rotary shaft, a through hole communicating with the inside is formed in the bottom of the second housing, and the processing gas is supplied from the outer periphery of the rotary shaft Supply holes are formed.

  In a molten metal treatment apparatus for removing an unnecessary gas by stirring a molten metal and supplying a treatment gas, a treatment vessel containing the molten metal and a treatment drive which is disposed above the treatment vessel and which has a rotation driving shaft protruding downward And an agitator provided at the lower end of the gas supply / rotation drive mechanism and removably installed in the processing tank, wherein the agitator is driven at the proximal end by the rotation drive. A cylindrical first housing attached to the distal end side of the shaft and supplied with the processing gas; a rotation shaft inserted inside the first housing and having a proximal end coupled to the rotation drive shaft; The inner diameter and the outer diameter of the first housing are larger than the inner diameter and the outer diameter of the first housing, and the bottom of the first housing is provided with the bottom facing the first housing, and the tip of the rotary shaft Bottomed cylindrical second housing for supporting the shaft, and the second It has a rotary blade housed in the body and attached to the tip side of the rotary shaft, and a through hole communicating with the inside is formed in the bottom of the second housing, and the treatment from the outer periphery of the rotary shaft A supply hole for supplying gas is formed.

  In a stirrer attached to a rotary drive shaft for stirring water or an aqueous solution and supplying a processing gas, a tubular first casing having a base end side mounted on a tip end side of the rotary drive shaft and supplied with the processing gas An inner diameter and an outer diameter larger than an inner diameter and an outer diameter of the body, a rotary shaft inserted into the first housing and having a proximal end coupled to the rotary drive shaft; A bottomed cylindrical second housing, which is provided on the tip end side of the first housing with the bottom side facing the first housing side, and pivotally supports the tip end side of the rotation shaft, and in the second housing A rotary blade housed and mounted on the tip side of the rotary shaft is provided, and a through hole communicating with the inside is formed in the bottom of the second housing, and the processing gas is supplied from the outer periphery of the rotary shaft Supply holes are formed.

  By generating micro bubbles, it is possible to increase the surface area in the molten metal or the aqueous solution, and to retain the surface area in the molten metal or the aqueous solution for a long time.

Explanatory drawing which shows the degassing processing apparatus which concerns on the 1st Embodiment of this invention. The longitudinal cross-sectional view which shows the stirring apparatus and stirrer which were integrated in the same degassing apparatus. Explanatory drawing which shows the degassing process process by the same degassing apparatus. Explanatory drawing which shows the process result by the same degassing processing apparatus and other degassing processing apparatuses. Explanatory drawing which shows the process result by the same degassing processing apparatus and other degassing processing apparatuses.

  1 to 3 are views showing a degassing apparatus (molten metal processing apparatus) 10 according to a first embodiment of the present invention. As shown in FIG. 1, the degassing apparatus 10 is detachably attached to the processing tank 20, the gas supply / rotation drive mechanism 30 disposed in the vicinity of the processing tank 20, and the gas supply / rotation drive mechanism 30. The apparatus includes a stirrer 50, a flux feeder 100 and a dross remover 110 disposed in the vicinity of the processing tank 20.

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

  The flux feeding device 100 has a function of feeding the flux F to the molten aluminum P in the processing tank 20. The flux feeding device 100 has a plurality of hoppers and shooters etc. containing an aluminum removing agent as the flux F, and the aluminum removing agent of a predetermined component is compounded in a predetermined compounding ratio, and a predetermined amount is contained in the processing tank 20 Equipped with a function to

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

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

  The gas supply / rotation drive mechanism 30 includes a gantry 31, a post 32 vertically extending on the gantry 31 and swinging along an axis in the vertical direction, and an endless belt disposed along the post 32. 33, a slider 34 attached to the endless belt 33, and a drive motor 35 for driving the endless belt 33. A gas supply unit 36 for supplying the processing gas G is disposed in the gantry 31 and connected to a gas supply line 46 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 turned / lifted by the post 32.

  Stirring apparatus 40 includes a frame 41 attached to the tip of arm 39, a rotational drive motor 42 provided on the frame 41, a rotational drive shaft 43 with an outer diameter of 50 mm extending in the vertical direction, and a rotational drive motor 42 and a belt 44 stretched around the upper end of the rotational drive shaft 43, a cylindrical portion 45 for axially supporting the rotational drive shaft 43, and an agitator 50 detachably attached to the end of the rotational drive shaft 43 Is equipped. The cylindrical portion 45 and the rotation drive shaft 43 are made of metal and are not immersed in the molten aluminum P.

  A gas supply line 46 is connected to the cylindrical portion 45, and the processing gas G is supplied from the gas supply unit 36 described above. The processing gas is, for example, a non-oxidizing gas such as argon gas or nitrogen gas. A slight gap is provided between the cylindrical portion 45 and the rotation drive shaft 43, and the processing gas G is supplied into the first housing 51 described later through the gap. The supply of the processing gas G has the effect of cooling the heat received from the molten aluminum P and preventing the temperature rise of each part.

  The agitator 50 has a proximal end attached to the distal end side of the rotary drive shaft 43, and is inserted into the cylindrical first casing 51 airtightly coupled to the cylindrical portion 45, and inserted into the first casing 51, and is rotated. The inner diameter and the outer diameter of the rotary shaft 52 with an outer diameter of 50 mm, the proximal end of which is coupled to the drive shaft 43, and the inner diameter and the outer diameter of the first housing 51 A bottomed cylindrical second housing 53 is provided, with the bottom side facing the first housing 51 and pivotally supporting the tip end of the rotary shaft 52. The axial dimension of the second housing 53 is, for example, about 160 mm.

  In the second housing 53, a rotary blade 54 attached to the tip end side of the rotary shaft 52 is disposed. A through hole 53 b communicating with the inside is formed in the bottom 53 a of the second housing 53, and a supply hole 53 c having an inner diameter of about 1 mm to which the processing gas G is supplied from the outer periphery of the rotating shaft 52 is provided.

  A slight gap is provided between the first housing 51 and the rotating shaft 52, and the processing gas G is supplied to the second housing 53 through the gap, and is supplied to the through hole 53b through the supply hole 53c. Be done.

  It is desirable that the rotating blades 54 have a weak stirring power for the purpose of only diffusing the processing gas G while suppressing the stirring of the molten metal.

  The stirrer 50 is formed of carbon, silicon nitride or the like, and is immersed in the molten aluminum P.

  Next, a degassing method by the degassing apparatus 10 according to the present embodiment will be described with reference to FIG. After the aluminum is melted 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). Subsequently, a flux F of a predetermined component is introduced into the processing tank 20, the agitator 50 is lowered, and the rotary vanes 54 are immersed immediately below the surface of the molten aluminum in the processing tank 20. Then, the rotary blade 54 is rotated to stir the molten aluminum P, the dross D and the flux F for several minutes. Thus, the dross D is reformed and is separated from the molten aluminum P (step S2).

  Next, the agitator 50 is further lowered to position the second housing 53 near the bottom of the processing tank 20, and the rotary vanes 54 are rotated at 300 to 400 rpm. Then, the processing gas G is supplied from the gas supply unit 36 and blown out from the supply hole 53 c. By the action of the rotation of the rotary vanes 54, the inside of the through hole 53b becomes negative pressure, the processing gas G is sucked from the supply hole 53c, and is blown out into the second housing 53 from the through hole 53b together with the molten aluminum P. Then, along with the injection effect at the time of blowing out and the rotary vanes 54 in the second housing 53, the processing gas G which has been made into microbubbles (diameter: several μm to 50 μm) is diffused. When the processing gas G is supplied and diffused into 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 metal (step S3). The stirring power at this time is weak to such an extent that the gas bubbling reaction is not inhibited. After bubbling for several minutes, the gas injection is stopped and the degassing process is finished.

Next, the stirrer 50 is further lowered to position the rotary vanes 54 at the deepest position of the processing tank 20 to stir the molten aluminum P. The dross scraping member is lowered to immerse the lower part thereof in the surface of the hot water, and the dross D is gathered at a specific place in the processing tank 20 (step S4). The collected dross D is sucked and discharged from the processing tank 20 by the suction and discharge device, and collected in the collection pot (step S5).
(Example)
Next, with regard to the embodiment of the degassing apparatus 10 described above, the aluminum alloy is subjected to a degassing process by flux injection and gas bubbling, using the conventional degassing apparatus as a comparative example, and the processing effects are compared. The alloy used is JIS aluminum alloy AC4CH (Si: 6.5 to 7.5%, Mg: 0.25 to 0.45%, Fe <0.20%, Ti <0.20%, balance: aluminum and other mixed components 6 kg, and 40 g of flux, and after stirring for 3 minutes, Ar gas is introduced for 5 minutes to perform degassing treatment. The gas amount is 5 L / min in the comparative example and 0.1 L / min in the example. As a method of judging the treatment effect, the aluminum alloy after treatment is passed through a ceramic filter, and the solid aluminum alloy remaining on the ceramic filter is recovered. Then, the ratio of the gas hole area in the range of 10 mm high × 14 mm wide from the filter interface of the aluminum alloy was measured by image analysis processing. The untreated alloy, the comparative example, and the example were analyzed as n = 10, and the results are shown in Table 1.

  Further, FIG. 4 shows the data described above as Boxplot, ie, a box and whisker plot. Furthermore, when the difference of the population mean of the data in the comparative example and the example was t-tested, it became clear that there is a significant difference. As shown in FIG. 5, when the images of the example and the comparative example are compared, even with the conventional degassing device, the gas holes in the range up to 0.5 mm in height immediately above the filter could be removed almost completely. It can be seen that the processing effect in the range of up to 10 mm in height where the influence of the oxide is exerted is limited. On the other hand, in the degassing treatment apparatus 10, gas holes up to 10 mm in height can be removed more effectively. It is presumed that this has an effect of adsorbing and removing the floating oxide on fine bubbles. From the above results, regarding the aluminum alloy AC4CH, a significant difference was observed in the ratio of the gas holes in the comparative example and the example, and it was clarified that the above-described degassing treatment apparatus 10 exhibits an effect.

  As described above, according to the stirrer 50 and the degassing apparatus 10 according to the present embodiment, the surface area of the processing gas in the molten metal is increased by generating the microbubbles, and the reaction with oxygen gas is facilitated. At the same time, by staying in the molten metal for a long time, the reaction time to oxygen gas can be extended and oxygen gas can be sufficiently removed. Further, the upper surface (bottom surface) of the second housing 53 accommodating the rotary vanes 54 is formed with a through hole having a minimum diameter necessary to suck the molten metal in an amount corresponding to the negative pressure accompanying the rotation of the rotary vanes 54. Therefore, the formation of a vortex on the surface of the molten metal can be prevented, and the formation of an oxide can be prevented by involving the atmosphere. That is, it is possible to discharge the microbubbled process gas, to suppress excessive stirring of the molten metal, and to promote dispersion of the process gas. Therefore, degassing can be sufficiently performed, and a high quality aluminum alloy can be obtained.

  In addition, although the aluminum alloy was illustrated as a metal mentioned above, it is applicable also to the molten metal of other metals, such as a magnesium alloy.

  In addition to the molten metal, it is possible to increase the reaction efficiency of the processing gas into the liquid and extend the reaction time by using the microbubbles having a diameter of about several μm to 50 μm in water, an aqueous solution, etc. And the amount of processing gas can be saved.

  Although only one through hole 53b is provided in FIGS. 1 and 2, a plurality of through holes may be provided.

  The present invention is not limited to the above embodiment, and can be variously modified in the implementation stage without departing from the scope of the invention. In addition, the embodiments may be implemented in combination as appropriate, in which case the combined effect is obtained. Furthermore, various inventions are included in the above-described embodiment, and various inventions can be extracted by a combination selected from a plurality of disclosed configuration requirements. For example, even if some configuration requirements are deleted from all the configuration requirements shown in the embodiment, the problem can be solved, and if an effect is obtained, a configuration from which this configuration requirement is removed can be extracted as the invention.

  DESCRIPTION OF SYMBOLS 10 Degassing processing apparatus 20 Processing tank 30 Rotational drive mechanism 31 Frame 32 Post Post 33 Endless belt 34 Slider 35 Drive motor 36 Gas supply part 39 Arm 39 DESCRIPTION OF SYMBOLS 40 ... Stirring apparatus, 41 ... Mounting frame, 42 ... Rotational drive motor, 43 ... Rotational drive shaft, 45 ... Cylindrical part, 46 ... Gas supply line, 50 ... Stirrer, 51 ... 1st housing | casing, 52 ... Rotational axis, 53 ... 2nd case, 53a ... bottom, 53b ... through hole, 53c ... supply hole, 54 ... rotating blade, 100 ... flux injection device, 110 ... dross removing device, 200 ... melting furnace, P ... molten aluminum, D ... dross , F ... flux.

Claims (3)

In a stirrer attached to a rotary drive shaft for stirring molten metal and supplying processing gas,
A tubular first casing having a proximal end side attached to a distal end side of the rotational drive shaft and supplied with the processing gas;
A rotary shaft inserted inside the first housing and having a proximal end coupled to the rotary drive shaft;
The inner diameter and the outer diameter of the first housing are larger than the inner diameter and the outer diameter of the first housing, and the bottom of the first housing is provided with the bottom facing the first housing and the tip of the rotation shaft A bottomed cylindrical second housing pivotally supporting the side;
It has a rotary blade housed in the second housing and attached to the tip end side of the rotary shaft,
A stirrer in which a through hole communicating with the inside is formed at the bottom of the second housing, and a supply hole for supplying the processing gas from the outer periphery of the rotation shaft is formed. In a melt processing apparatus for removing unnecessary gas by stirring the molten metal and supplying processing gas,
A processing tank for containing the molten metal;
A gas supply / rotation drive mechanism disposed above the processing tank and having a rotation drive shaft projecting downward;
It has a stirrer provided at the lower end of this gas supply / rotational drive mechanism and removably installed in the processing tank,
The agitator has a proximal end side attached to the distal end side of the rotary drive shaft and a cylindrical first casing to which the processing gas is supplied;
A rotary shaft inserted inside the first housing and having a proximal end coupled to the rotary drive shaft;
The inner diameter and the outer diameter of the first housing are larger than the inner diameter and the outer diameter of the first housing, and the bottom of the first housing is provided with the bottom facing the first housing and the tip of the rotation shaft A bottomed cylindrical second housing pivotally supporting the side;
It has a rotary blade housed in the second housing and attached to the tip side of the rotary shaft,
The melt processing apparatus according to claim 1, wherein a through hole communicating with the inside is formed at a bottom portion of the second housing, and a supply hole for supplying the processing gas from an outer periphery of the rotation shaft is formed. In a stirrer attached to a rotary drive shaft for stirring water or aqueous solution and supplying processing gas,
A tubular first casing having a proximal end side attached to a distal end side of the rotational drive shaft and supplied with the processing gas;
A rotary shaft inserted inside the first housing and having a proximal end coupled to the rotary drive shaft;
The inner diameter and the outer diameter of the first housing are larger than the inner diameter and the outer diameter of the first housing, and the bottom of the first housing is provided with the bottom facing the first housing and the tip of the rotation shaft A bottomed cylindrical second housing pivotally supporting the side;
It has a rotary blade housed in the second housing and attached to the tip end side of the rotary shaft,
A stirrer in which a through hole communicating with the inside is formed at the bottom of the second housing, and a supply hole for supplying the processing gas from the outer periphery of the rotation shaft is formed.