JPH036970B2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a processing device for molten metal such as aluminum or magnesium, and more specifically, a processing device that discharges a processing gas into the molten metal in the form of fine bubbles, and The present invention relates to a device used to remove dissolved harmful gases such as hydrogen gas and nonmetallic inclusions from the molten metal by dispersing the bubbles throughout the molten metal.

In this specification, the terms "aluminum" and "magnesium" are used to include not only pure aluminum and pure magnesium but also aluminum alloys and magnesium alloys.
In addition to argon gas, helium gas, krypton gas, and xenon gas in the periodic table, the term "inert gas" also refers to gases that are inert to the metal to be melted, such as nitrogen, which is inert to aluminum. It is also used to include gas, etc.

Prior art and its problems Conventionally, the above-mentioned molten metal processing equipment has a molten metal processing tank having an opening at the upper end, and a processing gas passage arranged inside the molten metal processing tank and extending longitudinally inside the molten metal processing tank. a rotating body for releasing and dispersing air bubbles, which is provided at the lower end of the vertical rotating shaft and has a processing gas outlet connected to the processing gas passage of the vertical rotating shaft on the bottom surface; A baffle plate was used to prevent eddy currents and ripples (see Utility Model Application No. 161162/1983). Then, the vertical rotating shaft is rotated while feeding a processing gas such as inert gas or chlorine gas into the processing gas passage of the vertical rotating shaft, and the processing gas is released into the molten metal in the form of fine bubbles, and the entire molten metal is released. Molten metal was processed by dispersing it in

However, in conventional devices, the vertical rotation shaft, rotating body, and baffle plate were generally made of graphite. However, although graphite has excellent heat resistance, thermal shock resistance, and wettability with molten metal, it is consumed due to erosion caused by the molten metal flowing in the processing tank during molten metal processing and oxidation during heating in a high-temperature atmosphere. It has the disadvantage of being intense. Therefore, there is a problem in that these members need to be replaced frequently, which increases costs. Moreover, the vertical rotation axis
In order to collect or replace the rotating body and baffle plate, it is necessary to raise the rotating shaft to take it out of the processing tank and to remove the lid, which is a cumbersome task. It is also possible to make the vertical rotating shaft, rotating body, and baffle plate from ceramics such as alumina, but this has poor thermal shock resistance and is likely to break due to thermal shock if pulled up suddenly from high-temperature molten metal. There's a problem. Furthermore, it is conceivable to make the vertical rotating shaft, the rotating body, and the baffle plate from metal, but in this case, there is a problem that the metal gradually melts from the surface, changing the composition of the molten metal to be processed. In either case, it is necessary to replace these, which increases the cost and makes the work troublesome.

An object of the present invention is to provide a molten metal processing apparatus that solves the above problems.

Means for Solving the Problems The molten metal processing apparatus according to the present invention discharges processing gas in the form of fine bubbles into the molten metal placed in a processing tank, and spreads the bubbles throughout the molten metal. An apparatus for removing dissolved gases and non-metallic inclusions from molten metal by dispersing them, which includes a molten metal processing tank having an opening at the upper end, a support placed outside the processing tank, and a support located above the processing tank. an arm-shaped support that is attached to the support and is movable up and down along the support and rotatable around the axis of the support, and a processing gas passage that is provided in a manner that hangs down from the support and extends longitudinally inside the support. a vertical rotating shaft having a vertical rotating shaft; a rotating body for air bubble release and dispersion having a processing gas outlet provided at the lower end of the vertical rotating shaft and connected to the processing gas passage of the rotating shaft; At least one of the vertical rotating shaft, the rotating body, and the baffle plate is provided.
The bending strength obtained by mixing 10 to 0% by volume of ceramic powder with coke powder and sintering it is
It is made of a carbon-ceramic composite material having a weight of at least Kg/cm ² .

In the processing apparatus of the present invention, there are cases in which the vertical rotation shaft and the rotating body are made integrally, and cases in which they are both made separately and fixed by appropriate means. Furthermore, in the processing apparatus of the present invention, when all of the vertical rotation shaft, the rotating body, and the baffle plate are formed of a carbon-ceramic composite material, any two of the above three members are carbon-ceramic composites.
In some cases, it is formed of a ceramic composite material, and in some cases, any one of the three members described above is formed of a carbon-ceramic composite material.
In addition, when the vertical rotation axis and the rotation body are made integrally, the vertical rotation axis and the rotation body,
At least one of the baffle plates is formed of a carbon-ceramic composite material.

The reason why a carbon-ceramics composite material having a bending strength of 200 kg/cm ² or more obtained by blending 10 to 50 volume % of ceramic powder with coke powder and sintering is used is as follows. That is,
Coke, a carbon material, gives composite materials excellent thermal shock resistance, chemical stability, and high-temperature strength, and makes them lightweight, while ceramics provide excellent oxidation resistance, abrasion resistance, and mechanical strength. Grant. As the ceramic powder, boron carbide alone or a mixture of boron carbide and other carbides, borides, and oxides can be used. As the oxide, aluminum oxide is preferred. Even if only one type of ceramics other than boron carbide is mixed, two
More than one species may be mixed, and the blending amount is such that the amount of ceramics including boron carbide is 10% of coke
It should be within the range of ~50% by volume. If the content of this ceramic is less than 10% by volume, problems such as low bending strength and low oxidation resistance will occur; if it exceeds 50% by volume, there will be a decrease in thermal shock resistance and mechanical This may cause a decrease in workability. Further, a carbon-ceramic composite material can be obtained by blending a ceramic material into coke within the above range and performing pressure sintering or pressureless sintering. In this case, the sintering temperature is usually 1000-2300
℃ range.

Example This invention will be explained below with reference to the drawings.

In FIG. 1, the molten metal processing equipment is located on the floor F
A molten metal processing tank 1 installed above, a support mounting post 2 erected on the floor F outside the processing tank 1, and a support mounting post 2 above the processing tank 1 that can be freely moved up and down. An attached arm-shaped rotating shaft support 3, a vertical rotating shaft 4 for blowing processing gas having a processing gas passage 5 that is provided in a hanging manner on the supporting member 3 and extending in the longitudinal direction, and a lower end of the rotating shaft 4. A rotary body 6 for releasing and dispersing air bubbles, which is integrally provided and has a processing gas outlet 7 connected to the processing gas passage 5 of the rotating shaft 4 on the bottom surface; It consists of two baffle plates 8 for preventing eddy currents and ripples that can move toward and away from the shaft 4.

The vertical rotating shaft 4, the rotating body 6 for releasing and dispersing air bubbles, and the baffle plate 8 for preventing swirling current and ripples are all made by blending 10 to 50% by volume of ceramic powder into coke powder and sintering the mixture to obtain bending strength. 200
It is made of carbon-ceramic composite material with a weight of more than Kg/cm ² .

A removable top wall 9 is provided at the upper end of the processing tank 1, and an opening 10 into which the rotating shaft 4 and the baffle plate 8 can be inserted is formed in the top wall 9. The support mounting column 2 is provided on a pedestal 11 fixed to the floor F on which the processing tank 1 is placed so that it can rotate around an axis and can be fixed at any position. A ring 13 is fitted over the middle of the height of the support column 2 and fixed at a predetermined height position, and a bracket 14 is provided at the upper end. Support 3
is slidably fitted over the support column 2 at one end. A mechanism for moving the support body 3 up and down along the support column 2 is rotatably provided between the ring 13 and the bracket 14, and is screwed into a female screw hole 3a formed in the support body 3 to move the support body 3 up and down. The threaded shaft 15 passes through the bracket 14, and is mounted on the bracket 14.
It consists of a motor 18 that rotates a screw shaft 15 through gears 16 and 17. By driving the motor 18, the screw shaft 1 is
5 rotates, and the support body 3 moves up and down. When the support body 3 is in the raised position, the rotating body 6 and the baffle plate 8 come out of the tank 1. Further, the support body 3 is configured to rotate together with the support column 2 around the axis of the support column 2. The support body 3 is provided with a rotation drive mechanism for a vertical rotation shaft 4 . This rotational drive mechanism consists of a motor 20 attached to a support 3, a vertical cylindrical bearing 21 attached to the tip of the support 3, and a rotary motor 20 supported by the bearing 21 so as to be rotatable but not vertically movable. It consists of a drive shaft 22, a pulley 23 attached to the driving shaft of the motor 20, a pulley 24 attached to the rotary drive shaft 22, and a belt 25 hooked around both pulleys 23 and 24. A vertical rotation shaft 4 is fixed to the lower end of the rotation drive shaft 22 via a flange joint 26, and the rotation shaft 4 is rotated by a motor 20 via pulleys 23, 24, a belt 25, and the rotation drive shaft 22. . A processing gas passage 27 that is connected to the processing gas passage 5 of the rotation shaft 4 is provided inside the rotary drive shaft 22 . A rotary seal 2 is installed at the upper end of the processing gas passage 27 of the rotation drive shaft 22.
A processing gas supply pipe 29 extending from a processing gas supply source (not shown) is connected via 8 . A plurality of grooves (not shown) are radially provided on the bottom surface of the bubble releasing and dispersing rotating body 6 from the processing gas outlet 7 to the peripheral edge. A plurality of vertical grooves 30 are provided between the openings of the radial grooves on the circumferential surface of the rotating body 6. The baffle plate 8 for preventing swirling currents and ripples is suspended from the lower end of a hanging member 32 that is attached to two arms 31 that are provided on the bearing 21 so as to protrude left and right, respectively, so as to be slidable in the left and right directions. It's lowered. The hanging member 32 is fixed to the arm 31 with a screw 33 at an arbitrary position. The baffle plate 8 is detachably attached to the suspension member 32 with screws 34. The lower end of the baffle plate 8 is positioned slightly below the rotating body 6.

To process molten metal with such a processing device, first raise the support 3 and place it in the processing tank 1.
Place molten metal inside. Further, the support body 3 is rotated so that the vertical rotation axis 4 and the baffle plate 8 are directly above the opening 10 by rotating the column 2, and the baffle plate 8 is baffled so that it enters the tank 1 through the opening 10. The distance between the plate 8 and the rotating shaft 4 is adjusted in advance. Next, the motor 18 rotates the screw shaft 15 via the gears 16 and 17 to lower the support 3 along the support column 2 and the screw shaft 15, and the vertical rotation shaft 4 and the baffle plate 8 are moved through the opening 10 into the processing tank. 1 and immersed in molten metal. In this state, a processing gas is supplied from a processing gas supply source (not shown) to the rotating body 6 via the processing gas supply pipe 29, the processing gas passage 27 of the rotation drive shaft 22, and the processing gas passage 5 of the rotation shaft 4, and The motor 20 rotates the rotary drive shaft 22 and the rotary shaft 4. Then, from the lower end opening of the processing gas passage 5 of the rotating shaft 4 to the blowing outlet 7 of the rotating body 6.
The processing gas discharged to the bottom surface is turned into fine bubbles and dispersed throughout the tank 1 by the centrifugal force generated by the rotation of the rotating body 6 and the action of the radial grooves and vertical grooves 30 on the bottom surface. released. Hydrogen gas and nonmetallic inclusions in the molten metal are removed by this processing gas.

After removing hydrogen gas and nonmetallic inclusions from the molten metal, or when replacing or repairing the rotating shaft 4 and the baffle plate 8, the screw shaft 15 is rotated by the motor 18 and the support body 3 is raised. The rotating shaft 4 and the baffle plate 8 are taken out of the processing tank 1, and the support column 2 is rotated to move both to a position where they are removed from directly above the tank 1, and replacement or repair work is performed at this position. Also,
When removing dross floating on the surface of the molten metal after removal of hydrogen gas and non-metallic inclusions, or performing maintenance and inspection work inside the processing tank 1, first raise the support 3 to remove the dross floating on the surface of the molten metal. After taking it outside, rotate pillar 12
The support 3 is rotated and moved to a position away from directly above the tank 1. By doing so, the rotating shaft 4 and the baffle plate 8 do not get in the way during dross removal work or maintenance inspection work in the processing tank 1, and workability and safety are improved.

In the embodiment described above, the processing apparatus of the present invention is applied to a batch-type processing apparatus in which molten metal to be processed is put into a processing tank, processed there, and then sent to other processes. However, the present invention may be applied to an in-line processing apparatus in which a processing tank is provided on the flow path of the molten metal and the molten metal is processed while being continuously circulated through the processing tank.

Next, a durability test of the vertical rotating shaft 4 and the rotating body 6 conducted using the apparatus shown in FIG. 1 will be described.

Put molten aluminum into treatment tank 1 and
The temperature was maintained at 700-750°C. Then, the support body 3 was lowered, the rotating shaft 4, the rotating body 6, and the baffle plate 8 were immersed in the molten aluminum, and the rotating shaft 4 and the rotating body 6 were rotated at 1000 rpm. Rotating axis 4
The life of the rotating body 6 was 60 days.

For comparison, a test similar to the above was conducted using a rotating shaft and rotating body integrally formed of graphite, and the lifespan was 3 days.

Effects of the Invention According to the molten metal processing apparatus of the present invention, at least one of the vertical rotating shaft, the rotating body, and the baffle plate is obtained by blending 10 to 50% by volume of ceramic powder with coke powder and sintering the mixture. Bending strength 200Kg/
Since it is made of a carbon-ceramic composite material having a diameter of cm ² or more, it has the following effects. That is, carbon-ceramic composite materials have low density and high strength, and have excellent oxidation resistance and thermal shock resistance, and moreover, the bending strength tends to increase as the temperature increases. Therefore, the durability of parts made using this material is dramatically improved, and replacement of parts is much easier than if the vertical rotation shaft, rotating body, and baffle plates were all made of graphite, ceramics, or metal. The cycle becomes longer and the cost becomes cheaper.

In addition, when replacing or repairing the vertical rotating shaft, rotating body, and baffle plate, the support body should be raised to take them out of the processing tank, and then the support body should be rotated around the axis of the support to remove them from the processing tank. Since it can be moved from the position directly above, these replacement and repair operations can be easily performed, and the safety of the operations is improved.

[Brief explanation of the drawing]

The drawing is a vertical sectional view showing an embodiment of the device of the invention. 1... Processing tank, 2... Strut, 3... Support, 4
...Vertical rotation axis, 5...Processing gas passage, 6...Rotating body for bubble release and dispersion, 7...Processing gas outlet, 8
... Baffle plate for preventing swirling currents and ripples, 10... Opening.

Claims (1)

[Claims] 1 Release the processing gas in the form of fine bubbles into the molten metal placed in the processing tank 1, and disperse the bubbles throughout the molten metal to remove dissolved gas and nonmetallic inclusions from the molten metal. A device that
A molten metal processing tank 1 having an opening 10 at the upper end, a support 2 disposed outside the processing tank 1, a support 2 that is attached to the support 2 above the processing tank 1, and is movable up and down along the support 2. , an arm-shaped support 3 rotatable around the axis of the support column 2; a vertical rotation shaft 4 that is provided depending on the support 3 and has a processing gas passage 5 extending longitudinally therein;
A rotary body 6 for air bubble release and dispersion, which is provided at the lower end of the vertical rotary shaft 4 and has a processing gas outlet 7 connected to the processing gas passage 5 of the rotary shaft 4, and a rotary body 6 for releasing and dispersing air bubbles, which is provided in a hanging shape so as to be detachably attached to the support body 3. At least one of the vertical rotating shaft 4, the rotating body 6, and the baffle plate 8 adds 10 to 50% by volume of ceramic powder to the coke powder. A molten metal processing device made of a carbon-ceramic composite material having a bending strength of 200 Kg/cm ² or more obtained by blending and sintering.