JP2019098396A - Jet rotation type degasification device and gas nozzle - Google Patents

Abstract

To solve the problems that the ascent and descent operation of heavy articles in a rotation drive unit is caused every time, the operation is troublesome, a rotation shaft made of carbon is weak against shock and easily broken, the whole device is expensive and an operation using the rotation drive unit and the rotation shaft cannot be performed according to the installation state of a molten metal furnace in a conventional rotation agitation type degasification device.SOLUTION: In a jet rotation type degasification device: a jet gas nozzle 6 is disposed apart from a prescribed distance from the bottom surface of an aluminum melting furnace 5; nitrogen gas is supplied from a nitrogen gas supply pipe 7 to the jet gas nozzle 6; convection is generated in the aluminum melting furnace 5 by forming nitrogen gas bubbles 9 in a molten metal; and hydrogen gas and removed slag 10 are floated at the upper part of the molten metal and removed.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a degassing apparatus and a gas nozzle capable of removing hydrogen gas and deasphalt generated in molten aluminum with a simple apparatus.

  It is necessary to remove the deasphalt (suspension, oxide) and hydrogen gas which are the causes of quality deterioration in the aluminum foundry. That is, after the completion of melting, molten metal treatment is performed to remove oxides and hydrogen gas in the molten metal. The molten metal treatment includes degassing treatment for removing oxides and degassing treatment for removing hydrogen gas.

In the molten metal, various oxides and inclusions exist, and when they are caught in the product, they interfere with the mechanical properties of the product. A removal process is performed to remove these. Chloride-based and fluoride-based fluxes are used for deasphalting, and these are dispersed and stirred on the surface of the molten metal. The flux is decomposed in the molten metal to generate fine gas bubbles, and the oxide is adsorbed to the gas bubbles and floats up and separated.
Further, in the molten metal, hydrogen gas is absorbed according to the hydrogen partial pressure in the atmosphere. Although the hydrogen solubility in the liquid phase is high, the hydrogen solubility in the solid phase is extremely low. For this reason, among the hydrogen absorbed in the molten metal, the hydrogen exceeding the solubility limit at the time of solidification is released into the molten metal as molecular hydrogen gas and becomes bubbles. As a result, pinholes are generated in the cast product and the mechanical properties and pressure resistance are impaired.

  Conventionally, a rotary stirring type degassing apparatus as shown in FIG. 9 is used as a countermeasure against these problems. FIG. 9 (a) is a view schematically showing the configuration of this rotation stirring type degassing apparatus, in FIG. 9 (a), 101 is a molten metal furnace, 102 is a molten aluminum in the molten metal furnace 101, and 103 is a rotating mechanism. The rotation and stirring apparatus provided with the control mechanism 104, the rotating shaft 105, and the rotor 106 is shown. As shown in FIG. 9 (b), the rotor 106 is in the shape of a wheel, and small holes are formed so that the inert gas fed from the rotation mechanism / control mechanism 104 can be ejected as bubbles 107 from the periphery or the top. . In FIG. 9, nitrogen N 2 is illustrated as an example of the inert gas, but the same applies to other inert gases such as argon.

In the lower part of the rotor 106, an open type groove is cut, and since there are a gas passage surrounded by three faces and a gas passage surrounded by the pressure of the molten metal, in the case of no rotation, the bubbles are somewhat large. turn into.
In order to reduce the size of the bubbles, it is necessary to speed up the rotation speed and cut the gas bubbles. However, if the rotation is accelerated, it contributes to the removal of hydrogen gas, but more vortices are generated on the upper surface of the molten metal. There is a concern that the air will be taken in from the wall of the melt furnace, oxidation to even normal aluminum will be increased, aluminum suspended matter will increase, it must be removed, and the yield will deteriorate.

  Here, the mechanism by which hydrogen gas is removed by the rotary degassing apparatus will be described. When inert gas is blown into the aluminum alloy, hydrogen gas in the molten metal diffuses into inert gas bubbles and floats up. This is considered to be due to the relationship between the hydrogen gas partial pressure in the atmosphere and the hydrogen solubility in the molten metal. Also, particles of nonmetallic inclusions suspended in the molten metal are taken into bubbles of many fine inert gases and floated away.

  However, in the conventional rotary stirring type degassing apparatus, lifting and lowering work of the weight of the rotary drive occurs each time, and the work is difficult, and the rotating shaft is made of carbon, so it is weak to shock and easily broken. In addition, the entire apparatus is expensive, and depending on the installation condition of the molten metal furnace, there are problems such as that the work using the rotary drive device and the rotary shaft can not be performed.

  Japanese Patent Application Laid-Open No. 05-312485 (Patent Document 1) relates to an apparatus for introducing a gas for stirring into molten metal, and in FIG. 1, a spiral gas blowing pipe is disposed at the center of the furnace bottom. Although described, it is installed directly above the furnace bottom plate, and the shape is a near circular shape rather than a spiral shape.

JP 05-312485 A (FIG. 1)

As described above, in the conventional rotary stirring type degassing apparatus, lifting and lowering work of the weight of the rotary drive device occurs each time, and the work is heavy, and the rotating shaft is made of carbon, so it is weak against impact. There are problems such as easy breakage, high price of the whole apparatus, and inability to work using a rotary drive and a rotary shaft depending on the installation condition of the melt furnace. It is an object of the present invention to obtain a jet swirling degassing apparatus capable of removing swarf in a molten metal furnace with a simple apparatus having no rotating part.
In addition, it is easier to control the bubble size and the number of bubbles generated than the device shown in Patent Document 1, obtain a device having the effect of being able to contact bubbles and molten metal in a short time and not generating turbulent flow on the molten metal surface. The purpose is that.

The invention according to claim 1 is an apparatus for removing hydrogen gas and deasphalting generated in a molten aluminum furnace, the jet-type gas nozzle installed at a predetermined distance from the bottom surface of the molten aluminum furnace, and the jet-type gas nozzle And an inert gas generator for delivering the inert gas to the supply pipe, the inert gas is ejected from the jet gas nozzle to cause convection in the molten metal. The hydrogen gas and the deasphalted carbon are floated to the upper part of the molten metal to be removed.
According to the invention of claim 1, it is possible to remove hydrogen gas and swarf in the melt furnace with a simple device without a rotating part. Moreover, compared with the conventional rotation stirring type degassing apparatus, there exists an effect that installation is easy and workability | operativity is good.

The second aspect of the present invention is characterized in that the shape of the jet-type gas nozzle is a single stroke such as a spiral shape so that both ends of the gas nozzle are the inlet and the outlet of the gas. By so doing, air bubbles can be generated uniformly, and hydrogen gas and deasphalt can be removed efficiently.
The invention according to claim 3 is characterized in that the inert gas is supplied from both ends of the jet gas nozzle. By doing so, bubbles can be generated more evenly than in the second aspect, and hydrogen gas and deasphalting can be efficiently removed.
The invention according to claim 4 is characterized in that the jet gas nozzle is installed at a distance of 50 to 150 mm from the bottom surface of the molten aluminum furnace. By so doing, convection of nitrogen gas can be efficiently performed in the melt furnace, and hydrogen gas and swarf can be reliably removed.
The invention according to claim 5 is characterized in that the size of the inert gas jet port provided in the jet flow type gas nozzle is about 0.2 mm. By so doing, convection of the inert gas can be efficiently performed in the melt furnace, and hydrogen gas and swarf can be reliably removed.
The invention according to claim 6 is characterized in that generation control of the inert gas is controlled by a pulse control device by a pulse control device. By doing this, gas generation and control are easy, and there is a degree of freedom in adjustment. In addition, the particle diameter of the inert gas bubble can be freely changed by adjusting the introduction pressure of the gas, the pulse width and the speed.
The invention according to claim 7 is characterized in that a heat absorbing device for warming the inert gas using heat of the molten metal is provided in the middle of the inert gas supply pipe in the molten metal. By so doing, the heat of the molten metal can be used to warm the inert gas, and it is not necessary to provide a separate device for heating the inert gas. By warming the inert gas, the purity of the inert gas can be increased, the oxidation of the molten metal can be suppressed, and the hydrogen gas and the deasphalting can be reliably removed.
The invention according to claim 8 is characterized in that nitrogen or argon is used as the inert gas. By using nitrogen or argon as the inert gas, it is possible to remove hydrogen gas and deasphalt very efficiently.

The invention according to claim 9 relates to the structure of the gas nozzle used in the jet swirl system degassing apparatus of the present invention, wherein the shape of the gas nozzle is a single stroke and the both ends thereof are the inlet or outlet of the gas. Is configured.
According to a tenth aspect of the present invention, in addition to the ninth aspect, the gas nozzle is installed at a predetermined distance from the bottom surface of the molten aluminum furnace.

According to the jet swirl system degassing apparatus of the present invention, it is possible to remove hydrogen gas and swarf in the molten metal furnace with a simple apparatus having no rotating part. Moreover, compared with the conventional rotation stirring type degassing apparatus, installation is easy and workability | operativity is good.
In addition, an efficient jet gas nozzle can be obtained.

  The schematic block diagram which shows the structure of the whole jet flow whirl system degassing apparatus of this invention   The melt furnace and the side view of the degassing apparatus according to the first embodiment of the present invention   Plan view of the degassing apparatus shown in Embodiment 1 of the present invention   Diagram to explain the principle of hydrogen gas removal in molten metal   The top view of the degassing apparatus shown in Embodiment 2 of this invention   Top view of the degassing apparatus of the first modification of the second embodiment of the present invention   Top view of the degassing apparatus according to the second modification of the second embodiment of the present invention   The melt furnace and the side view of the degassing apparatus of the embodiment 3 of the present invention   Side view of conventional molten metal furnace and rotational stirring degassing apparatus

Embodiment 1
FIG. 1 is a schematic block diagram showing the entire configuration of the jet swirl system degassing apparatus according to the present invention, wherein 1 is a power source, 2 is a nitrogen gas generator with a built-in compressor, 3 is an oxygen removing catalyst, 4 is a touch panel 4a, high speed solenoid valve A pulse control device 4b is provided, 5 is a molten aluminum furnace, 6 is a jet gas nozzle, 7 is a nitrogen supply pipe, 8 is a molten aluminum, and 9 is a nitrogen gas bubble.
The nitrogen gas generated in the nitrogen gas generator 2 is pulsated from the pulse controller 4 through the oxygen removing catalyst 3 which is a reformer, and the molten metal furnace 5 is discharged through the nitrogen supply pipe 7. The hydrogen gas and the deasphalt are moved to the upper part of the melt furnace 5 and removed by squirting from a jet-type gas nozzle 6 installed in the vicinity of the bottom of the furnace.
In the apparatus of the first embodiment, the gas supply is a pulse system, and the gas is instantaneously transmitted from the supply port to each nozzle port at the time of gas supply. Further, by minimizing the amount of gas compression, it is possible to accurately discharge the pulse supply gas sequentially sent from the nozzle portion, and to continuously generate the fine bubbles and the amount of the bubbles intermittently.

Hereinafter, the jet gas nozzle 6 which is a main part of the jet swirling degassing apparatus will be described in detail with reference to FIG. The jet gas nozzle 6 is disposed at the bottom of the molten aluminum furnace 5 and is disposed at a constant distance h from the bottom of the molten iron furnace 5. This distance is selected to be 50 to 150 mm so that the nitrogen gas released from the jet gas nozzle 6 can be convected in the molten metal furnace 5 and the stirring effect can be sufficiently exhibited. Among these, convection is obtained most efficiently at about 100 mm.
Further, although a plan view of the shape of the jet gas nozzle 6 is shown in FIG. 3, the size of the gas jet nozzle 6 a provided to the jet gas nozzle 6 is desirably about 0.2 mm.

  The nitrogen gas injected from the nitrogen supply pipe 7 is released from the jet gas nozzle 6 as fine bubbles 9 toward the top. The bubbles 9 ascend from the jet gas nozzle 6 as shown by arrows in the figure, move outward on the upper surface of the molten metal and descend along the inner surface of the molten metal furnace 5 to cause convection. At that time, the hydrogen gas and the degassing vessel 10 are moved to the upper surface of the molten metal and removed.

  Next, with reference to FIG. 4, the removal of the molten metal hydrogen gas and the slag removal will be described. When the aluminum melt 8 heated in the melt furnace 5 changes from the solid phase to the liquid phase, the amount of hydrogen gas dissolved increases and bubbles remain, which lowers the quality of the product. Therefore, an inert gas such as nitrogen is blown to move the hydrogen gas suspended in the molten metal into the inert gas bubble 9 to float and be removed. This is because, due to the low hydrogen partial pressure of the inert gas bubble, suspended hydrogen gas moves into the inert gas bubble and floats up with the inert gas. At the same time, the deasphalt 10 such as oxides adhering to the periphery of the inert gas also floats on the surface of the hot water and is removed. In addition, although the example which used nitrogen as an example of an inert gas is shown in FIG. 4, the same effect is acquired even if it uses argon.

Second Embodiment
FIG. 5 is a plan view of a jet gas nozzle 60 according to a second embodiment of the present invention. In the jet-type gas nozzle 60, one pipe of the nozzle is formed in a spiral shape, nitrogen gas is supplied from a nitrogen supply port 60a at one position of the spiral pipe, and nitrogen gas is supplied from a gas jet port 60b formed in the pipe Air bubbles are released. In addition, in FIG. 5, the gas jet nozzle 60b formed in the pipe is showing the one part.
The spiral jet-type gas nozzle 60 shown in the second embodiment is also disposed at a constant distance of 50 to 150 mm with the bottom surface of the molten metal furnace 5.

FIG. 6 shows a modification 1 of the second embodiment. In the jet gas nozzle 61, one pipe of the nozzle is formed in a spiral shape, and both the outer nitrogen supply port 61a and the inner nitrogen supply port 61b are used. It is configured to be supplied with nitrogen gas. Therefore, nitrogen gas can be ejected from the entire gas nozzle 61 uniformly into the molten metal.
6 schematically shows the configuration of the nozzle, the thickness of the pipe is omitted, and the gas jet port formed in the pipe is also omitted.
The spiral jet-type gas nozzle 61 shown in the first modification of the second embodiment is also arranged at a fixed distance of 50 to 150 mm with the bottom surface of the molten metal furnace 5.

FIG. 7 shows a modification 2 of the second embodiment, in which two jet flow type gas nozzles 62 are formed in a spiral shape with substantially equal intervals, and one pipe 62c is provided with an outer supply port 62a. The nitrogen gas is supplied to the other pipe 62d from the inner supply port 62b. Also in this case, as in the first modification of the second embodiment shown in FIG. 6, there is an effect that nitrogen gas can be ejected from the whole of the gas nozzle 62 uniformly into the molten metal.
6 schematically shows the configuration of the nozzle, the thickness of the pipe is omitted, and the gas jet port formed in the pipe is also omitted.
The spiral jet-type gas nozzle 62 shown in the second modification of the second embodiment is also arranged at a constant distance of 50 to 150 mm with the bottom surface of the molten metal furnace 5.

Third Embodiment
FIG. 8 is a side view showing a molten metal furnace and a degassing apparatus according to Embodiment 3 of the present invention, and the difference from Embodiment 1 shown in FIG. 2 is in the middle of nitrogen gas supply pipe 7 in molten metal 8. It is a point provided with the heat absorption device 11 which warms nitrogen gas. The heat absorbing device 11 can efficiently heat the nitrogen gas by utilizing the heat of the molten metal of about 600 degrees. By providing the heat absorbing device 11, the purity of the supplied nitrogen can be further enhanced.
The heat absorbing device 11 has a configuration in which, for example, a part of the nitrogen supply pipe 7 is bent a plurality of times to expand the surface area, or a part of the nitrogen supply pipe 7 is branched to a plurality of parts to expand the surface area. Thus, the heat in the molten metal 8 can be efficiently transferred to the nitrogen gas.

In the first, second, and third embodiments, the jet-type gas nozzles 6, 60, 61, 62 are installed in one stage at the bottom of the molten metal furnace 5, but for example, installed in multiple stages as in upper and lower two stages. It is also possible. In particular, in the case of the configuration as shown in the second modification of the second embodiment shown in FIG. 7, it is possible to prevent the two pipes from being in proximity to each other, thus providing an effect of facilitating installation. Even in this case, the bottom surface of the lower jet-type gas nozzle and the bottom surface of the molten metal furnace 5 are disposed with a predetermined distance of 50 to 150 mm.
In addition, although nitrogen is taken as an example of the inert gas in the first to third embodiments, the same effect can be obtained by using argon.

  As described above, according to the jet swirl system degassing apparatus of the present invention, installation is easy, floating hydrogen gas can float at the shortest distance, 360 ° jet agitation enables uniform agitation, and gas generation control There are many merits and characteristics such as that the particle size of the bubble (bubble) can be changed by the change of the introduction pressure of the gas, the pulse width and the speed, which has the freedom of adjustment for the pulse system.

1: Power supply 2: Nitrogen gas generator 3: Oxygen removal catalyst 4: Pulse controller, 4a: Touch panel, 4b: High speed solenoid valve 5: Molten aluminum furnace 6: Jet gas nozzle, 6a: Gas jet port 7: Nitrogen gas supply Tube 8: Molten metal 9: Nitrogen gas bubble 10: Decarburization 11: Heat absorption device 60: Jet type gas nozzle, 60a: Nitrogen supply port, 60b: Gas jet port 61: Jet type gas nozzle, 61a: Outer nitrogen supply port, 61b Inside nitrogen supply port 62: jet gas nozzle 62a: outside supply port 62b: inside supply port 62c: one pipe 62c, 62d: the other pipe

Claims (10)

  In an apparatus for removing hydrogen gas and deasphalting generated in a molten aluminum furnace, a jet-type gas nozzle installed at a predetermined distance from the bottom surface of the molten aluminum furnace and an inert gas supplying inert gas to the jet-type gas nozzle A gas supply pipe and an inert gas generator for delivering an inert gas to the inert gas supply pipe are provided, and the inert gas is ejected from the jet gas nozzle to form molten aluminum and bubbles in the melt furnace. A jet swirl system degassing apparatus characterized in that convection of inert gas is caused to float the hydrogen gas and the deasphalt above the molten metal for removal.   The jet swirl type degassing apparatus according to claim 1, wherein the shape of the jet type gas nozzle is a single stroke, and both ends thereof are an inlet or an outlet of the gas.   The jet swirl system degassing apparatus according to claim 1 or 2, wherein the inert gas is supplied from both ends of the jet gas nozzle.   2. The jet swirling degassing apparatus according to claim 1, wherein the jet gas nozzle is installed at a distance of 50 to 150 mm from the bottom surface of the molten aluminum furnace.   2. The jet swirl system degassing apparatus according to claim 1, wherein the size of the inert gas jet port provided in the jet gas nozzle is about 0.2 mm.   The jet swirl system degassing apparatus according to claim 1, wherein the supply of the inert gas to the jet gas nozzle is a pulse-controlled inert gas by a pulse control device.   2. The jet swirling degassing apparatus according to claim 1, further comprising a heat absorbing device for warming the inert gas using heat of the molten metal in the middle of the inert gas supply pipe in the molten metal. .   The jet swirl system degassing apparatus according to any one of claims 1 to 7, wherein the inert gas is nitrogen or argon.   It is a jet-type gas nozzle used for an apparatus for removing hydrogen gas and degassing generated in a molten aluminum furnace, wherein the jet-type gas nozzle has a single-stroke shape, and both ends thereof are gas inlet or outlet. A jet gas nozzle characterized in that it is configured.   It is a jet-type gas nozzle used for an apparatus for removing hydrogen gas and degassing generated in a molten aluminum furnace, wherein the jet-type gas nozzle is installed at a predetermined distance from the bottom of the molten aluminum furnace. The jet gas nozzle according to claim 9, characterized in that:

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