JPS6283431A - Refining apparatus for molten aluminum - Google Patents

Abstract

PURPOSE:To effectively remove impurities from molten Al, by uniformly and finely dispersing refining gas by a specified short cylindrical rotary tube, at refining molten Al by blowing refining gas therein from bottom part of a treating vessel. CONSTITUTION:Molten Al is poured from an inlet 8 of the treating vessel 1, refining gas is supplied from a porous plug 2 at a treating chamber 11 to perform refining and exhausted from an outlet 7 through an outlet chamber 12. Thereat, the short cylindrical rotary tube 6 is hung into molten Al through a rotary shaft 8 and rotated by a driving means 4. Plural brades 7 are protrudently provided to the tube 6 and an angle of the brade 7 is slanted by 10-45 deg. to the shaft line. It is favorable to adopt about 20-60mm to a height (h) of the tube 6 and about 20-10mm to a length (l) of the blade 7. In this way, refining gas introduced in molten A4l is pervaded into molten metal over a wind range under fine bubble state to effectively remove impurities in molten metal.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to the refining treatment of molten aluminum, and more specifically, the present invention relates to the purification treatment of molten aluminum, and more specifically to the purification of impurities such as hydrogen gas and nonmetallic inclusions of oxides such as aluminum or magnesium contained in the molten metal. The present invention relates to a device for effectively removing.

<Prior art and its problems> Molten aluminum used to produce ingots contains hydrogen gas and nonmetallic inclusions of oxides such as aluminum and magnesium.

If an ingot is produced using aluminum molten metal containing hydrogen gas or non-metallic inclusions, the resulting ingot and the products made from this ingot may be defective. .

Therefore, when producing an ingot from molten aluminum, it is necessary to perform a molten metal purification treatment to remove hydrogen gas and nonmetallic inclusions.

Conventionally, methods used to remove impurities such as hydrogen gas and non-metallic inclusions include inert gases such as nitrogen gas and argon gas, or reactive gases such as chlorine gas and chlorofluorocarbon gases. Alternatively, it can be injected through a graphite pipe or the like. In this method, it is difficult to obtain high processing efficiency because the bubbles of the blown gas are large and it is difficult to bring the bubbles into contact with the entire molten metal.

Therefore, in order to improve these points, for example, as shown in Japanese Patent Publication No. 52-36487, a rotor is installed at the lower end of the stator, and the gas for purification is introduced into the elution process from the gap between the two, and the rotation There is a method and apparatus in which the gas introduced by rotating the child at high speed is subdivided into fine gas bubbles and brought into contact with the molten metal.

According to method B, a sufficiently satisfactory result can be obtained in terms of processing efficiency, but it is necessary to configure the stator and rotor as a body, and furthermore, it is necessary to ensure that the space between the stator and rotor is properly adjusted. The structure becomes complicated as it must be held in the gap.

In addition, there is a problem in that the stator, rotor, etc. are subject to rapid wear and tear, making the task of replacing them extremely complicated.

In a similar method, gas is introduced from the nozzle or gas blowing pipe at the bottom of the tank, or from the inside of the rotating shaft, as shown in Japanese Patent Application Laid-Open No. 58-144438. A method and device have also been proposed in which the gas is allowed to remain in the stagnation part and is dispersed into the molten metal by rotation of a rotor.

In this method, the gas is introduced into the gas retention area from the nozzle and pipe or the rotating shaft, and in this gas retention area, the gas is introduced into the gas retention area. Medium ((uniform dispersion lj,!:
9.I want to do it. Also, when the shape of the rotor from the first to the end of the rotating shaft to get the gas to flow becomes complicated! /fl also exists 4, 1 <Means for solving the problems - 4)> The present invention (1 Part 1j: Refining gas i
+PI411111'bubble ((during elution 11.11
; b Surrounding ((To distribute the gas: (, one person is placed on the stirring blade of the refining gas, and two people are placed on the agitation blade.
A $h gas supply pipe is opened directly or through a porous plug at the bottom of the processing tank, which has a ram molten metal outlet 11 and an outlet 11, respectively, and the processing tank 11
A short cylindrical rotary cylinder suspended from the l1 rotation shaft and connected to the lower end of the l1 rotary shaft is connected to the l- and 1. the required interval l
An apparatus for refining molten aluminum, characterized by a skein mortar device, and a plurality of blades protruding from the outer circumferential surface of the rotary cylinder at an angle of 10 to 45 degrees with respect to the axis of the rotary cylinder. It is.

In the device of the present invention, the blades protruding from the outer circumferential surface of the rotary cylinder are inclined at an angle of 10 to 45 degrees with respect to the axis. In order to disperse the refining gas as far down as possible into the processing tank, the angle must be at least 10° to avoid the formation of downward components, and if it exceeds 45°, the whole -C because the stirring power is weakened.

The reason why the blades are tilted as in B is to disperse the purified gas downward.-C1 It goes without saying that there is a certain relationship between the direction of inclination of the blades and the direction of rotation of the rotating shaft. and Operation> The apparatus of the present invention will be described in detail below with reference to the drawings showing the embodiments thereof.

Fig. 1 shows an embodiment of the present invention apparatus, which is installed at the bottom of the processing tank (1) and connected to a porous plug (2) and a purified gas supply pipe (3) inside the processing tank (1). Purified gas will be introduced into the area. A rotating shaft (5) having a driving means (4) at the upper part is suspended in the treatment tank (1), and a rotating cylinder (6) is attached to the lower end of the shaft. The shape is as shown in the figure, and the rotating cylinder (
A plurality of blades (7) are provided protruding from the outer periphery of 6).

The driving means (4) above the rotating shaft (5) is first rotated by an electric motor, an air motor, etc., and thereby the rotating shaft (5)
and the rotating cylinder (6) rotates (the porous plug at the bottom of the tank (7)
2) Uniformly and finely disperse the purification gas blown into the elution medium.

The rotary cylinder (6) used in the present invention has blades (7) on the outer periphery of the porous plug at the bottom of the tank.
~8L! The angle of the blade of J Tokoro Mata Otsu is I', l [! I/
As mentioned above, a range of 10 to 45 degrees with respect to the axis is preferable. More preferably, the height of the rotating cylinder) 1 is 20 to 60III
It is preferable that the length l of one blade is 20 to 10 nII11.

In addition to the shape of the rotating cylinder (6) shown in Fig. 2, there is also one in which the diameter gradually becomes larger towards the bottom as shown in Fig. 4. By doing this, refining gas can be sent downward more efficiently.

In the figure, (8) is the molten metal F1, (9) is the molten metal [-1, (
10) is a partition plate provided in the processing tank (1),
On the first cutting plate (10), the processing tank (1) is divided into a processing chamber (11) and an output chamber (2), and the partition plate (10) is used for refining. Suspended particles such as hydrogen gas and non-metallic inclusions trapped in gas microbubbles and suspended particles floated to the surface. This prevents the flow to (11).

The size of the processing tank (]), especially the size of the processing chamber (+1) and the size of the rotating cylinder (6) at the end of the rotating shaft, are such that the gas blown from the bottom of the tank will not flow into the processing chamber (11). It is only necessary to set it so that it is dispersed throughout the molten metal, and it is possible to use a method having a relatively high range. - For example, according to the results of the water-air model A experiment, the diameter ratio between the effective diameter of the treatment chamber (11) and the rotating blade is approximately 02 to 06, and the diameter ratio between the rotating blade and the nozzle at the bottom of the tank is approximately 02 to 06. It is sufficient to set the ratio to about 1:12 to 06.

The effective diameter of the processing chamber (11) is the diameter if the cross-sectional shape of the processing chamber (11) is circular, and the diameter if it is square.
・Length of the side, in the case of a rectangle, the length of the short side. Also, the r&diameter of the rotating blade and nozzle refers to the longest part of its circumference.

Next, Figures 5 and 3 show an example in which two rotating cylinders are used for refining gas injection [I and two rotating cylinders, respectively], and the results are shown in Figures 5 and 5 respectively. Depending on the view of inclusions, methods such as those shown in Figures 5 and 6 may be adopted.

Next, the results of a purification test conducted using the apparatus of the present invention are shown.

The rotary cylinder used for continuous processing of pure aluminum using the apparatus shown in FIG. 1 is L-shaped as shown in FIG. That is, the diameter is 250 mm, the height of the blade is 50 mm, the angle of the blade is 10', and 6 blades are installed. The rotating shaft, rotating cylinder, etc. were removed and made of graphite. - A nozzle was provided so that the impulse-producing gas was positioned above the rotating cylinder 1a. The gap between this rotary cylinder and the nozzle is 50 InIn.
and l, 1. The treatment tank has a steel plate shell lined with a heat insulating board, and the inside is lined with high alumina bricks. A rectangular parallelepiped-shaped tank is used, and a partition plate is placed on the outlet side. did. Mat: The rotating shaft was arranged so that the center line of the rotating shaft was one point in the center of the processing chamber. The pure aluminum molten metal was continuously supplied to such an apparatus at a rate of 5000 kg/hr, and the rotating shaft was rotated at a speed of 30 Or, p, m, to process a total of 201 tons of elution. Purification gases include Ano Lgon 90vo 1% and chlorine 10vo 1%
A mixed gas was used and was supplied at a rate of ]Om'/hr.

Sampling was performed on the molten metal before and after the above-mentioned treatments, and the amount of hydrogen gas, the concentration of sodium and lithium, and the concentration of nonmetallic inclusions were measured.

The above results are shown in Table 1.

<Effects of the Invention> In the device of the present invention having the above configuration, the purification gas blown from the nozzle or porous plug at the bottom of the tank is transferred to the bottom of the tank by the rotation of the rotating shaft (through the rotation of the rotating shaft), the gases do not coalesce together at the bottom of the rotating cylinder. This creates a turbulent flow state for the purification gas to be dispersed uniformly and finely during the elution, and the contact time between the elution and the bubbles can be extended, eliminating hydrogen gas or non-metallic inclusions present during the elution. The removal efficiency can be further increased by keeping the gap between the nozzle at the bottom of the tank or the polar suit lug and the rotating cylinder within a range of 20 to 100 mm.
7. Since the overall structure is very simple, it is easy to manufacture and replace.

Therefore, it is extremely effective in purifying aluminum elution.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of one embodiment of the device of the present invention, FIGS. 2 and 3 are a front view and a perspective view of the rotary cylinder portion, respectively, and FIG. 4 is a perspective view showing another form of the rotary cylinder. 5 and 6 are explanatory diagrams showing other embodiments of the apparatus of the present invention, respectively. In the diagram: (1) Treatment tank (5) Rotating shaft (6) Rotating tube (7) Vane Patent applicant Mitsui Aluminum Industries Co., Ltd. Agent Noriharu H.

Claims (1)

[Claims] 1. A refining gas supply pipe is opened directly or through a porous plug at the bottom of the processing tank, which has an inlet and an outlet for molten aluminum, and is connected to the lower end of a rotating shaft suspended from the top of the processing tank. The installed short cylindrical rotating tube is placed a required distance above the purification gas supply section, and the outer circumferential surface of the rotating tube has a 10-degree angle with the axis of the rotating tube.
A molten aluminum refining device characterized by a plurality of protruding blades tilted at ~45°.