JPH0741879A - Apparatus and method for refining aluminum alloy - Google Patents

Abstract

PURPOSE:To provide an apparatus and a method for refining an aluminum alloy containing metallic impurities having higher vaporizing pressures than aluminum, such as Zn, Mg. CONSTITUTION:The molten aluminum alloy 1 containing the metallic impurities enabling the vaporization and having comparatively high vaporizing pressures is dispersed as grains by blowing high temp. inert gas in a high temp. reduced pressure treating vessel 3. The dispersed granular molten materials 9 are exposed to the inert gas-flowing reduced pressure. The metallic impurities in the molten metal is vaporized because the molten material 1 is exposed to the high temp. and the reduced pressure in the granular state having the large surface area. Further, the vapor of the metallic impurities around the granular molten metal is removed from the surroundings of the granular molten metal by the flow of the inert gas, and the partial pressure of the metallic impurities around the granular molten metal is lowered. Therefore, the metallic impurities having high vapor pressure in the molten aluminum alloy are rapidly vaporized and removed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refining apparatus and a refining method for refining an aluminum alloy containing an impurity metal such as Zn, Mg and Pb having a vapor pressure higher than that of aluminum.

[0002]

2. Description of the Related Art Recycling of waste has become an important issue as part of effective use of resources. For example, to describe the current state of aluminum materials for automobiles, a three-layer composite material in which a brazing material is clad on one side of a core material and a sacrificial anode material is clad on the other side is used for a tube through which a refrigerant of an aluminum radiator passes, Since it is difficult to separate the composite layer, the scraps generated in the process of manufacturing this tube are used as a low-grade scrap as it is as a raw material for aluminum casting, a deoxidizing agent for molten steel, and the like. The scrap of the aluminum radiator is also used as a low-grade scrap because it takes time to disassemble. Most of the other aluminum scraps are also used in the same manner as the radiator. By the way, 2 wt% Zn was used for the core material of the tube.
% (Hereinafter abbreviated as%) added JIS-3003 alloy, etc., brazing filler metal such as JIS-4004 alloy containing 1.5% Mg, and sacrificial anode material JIS-7072 whose potential is lower than the core material Alloy (Al-Z
(n-type) and the like, and also for the fins and header plates of other constituent materials of the radiator, an aluminum alloy or an aluminum alloy composite material containing Mg or Zn as a main component is used. As described above, the aluminum radiator contains a large amount of Mg and Zn as alloying elements, and if refining technology for removing these alloying elements is developed, for example, the scraps of the tubes and the radiator are It can be reused as a raw material for brazing filler metal or fins, reducing the raw material cost and saving resources.

[0003]

[Problems to be Solved by the Invention] Zn from aluminum alloy scrap
A vacuum treatment method (Japanese Unexamined Patent Publication No. 20421/1988) has been proposed as a method for removing metallic impurities having a high vapor pressure such as Mg and Mg. In this method, as shown in FIG. 2, the melt 1 in the buffer container 31 is pumped by a melt pump 32 through a rising pipe 33, and the melt 1 in the rising pipe 33 is shown in a vacuum processing container 34. Do not collide with the baffle plate to atomize it, evaporate and remove metal impurities from the surface of this atomized melt 35, suck the vapor of metal impurities by a vacuum pump (not shown), and in the condenser 36 on the way. Will be collected at. After the metal impurities are removed, the atomized melt 35 is stored in the lower part of the vacuum processing container 34, and after being stored in the buffer container 38 through the downcomer pipe 37,
It was returned to the melting furnace 39. However, this method has not been put to practical use because the removal efficiency of metal impurities is low.

[0004]

DISCLOSURE OF THE INVENTION The present invention has conducted extensive studies in view of such circumstances, and the reason why the removal efficiency of metal impurities in the vacuum treatment method is low is that the vapor of metal impurities is present around the granular melt. It was discovered that the partial pressure of the metal impurities around the granular melt increased due to the covering, and as a result the evaporation rate of the metal impurities decreased, and further research was conducted to complete the present invention. .

That is, the invention of claim 1 is a refining apparatus for an aluminum alloy having a vapor pressure higher than that of aluminum and containing one or more kinds of metal impurities, and a melt holding furnace for holding a melt of the aluminum alloy. A depressurization processing container for decompressing the melt, a conduit serving as a passage for the melt from the melt holding furnace to the depressurization processing container, and supplying the melt in the holding furnace into the depressurization processing container. A melt supply means for granulating, a granulating means for granulating the melt supplied in the reduced pressure treatment container, deaeration in the reduced pressure treatment container and evaporation from the granulated melt in the reduced pressure treatment container Exhaust means for discharging the metal impurities, a metal impurity recovery chamber for recovering the metal impurities evaporated from the melt disposed between the decompression processing container and the exhaust means, and a metal impurity recovery chamber after the metal impurities are evaporated. For storing the melt An apparatus for refining an aluminum alloy comprising a melt storage tank, wherein the melt supply means comprises a gas pressurizer for pressurizing a space in a melt holding furnace, and the granulation means decompresses the conduit. An inert gas supply pipe is attached to the open end of the container, the open end of which is directed close to the open end of the conduit, and an inert gas heater is disposed in the middle of the inert gas supply pipe. And
A heating element is embedded in a wall portion of the decompression processing container, the melt storage tank is located in a lower portion of the decompression processing container, and at least a part thereof is below a side wall portion where the lower end of the decompression processing container is opened. The aluminum alloy refining device is characterized in that it is provided so as to project from the decompression processing container through the side.

In the apparatus of the present invention, the inert gas heater is provided in order to heat the inert gas and prevent the temperature of the melt from being lowered by spraying the inert gas. The reason why the heater was embedded in the side wall of the device is to heat the decompression treatment container to a high temperature to hold the granular melt at a high temperature, thereby promoting evaporation of metal impurities from the melt. The inert gas supply pipe is mounted in close proximity with its open end facing the open end of the melt supply conduit, but this number may be plural. Further, it may be mounted at a position away from the open end of the melt supply conduit to increase the amount of inert gas flowing around the granular melt. In this case, it is preferable that the mounting position is such that the inert gas passes through the portion where the granular melt falls, as long as possible. The melt holding furnace is arranged above the depressurization processing container, and the melt is supplied by utilizing gravity, so that the supply amount can be easily controlled. A plurality of melt-holding furnaces may be arranged or a plurality of conduits may be attached to one melt-holding furnace to increase the supply amount of the melt into the vacuum processing container. Further, by arranging two melt holding furnaces and supplying the melt alternately, continuous operation becomes possible.

A second aspect of the present invention is a method for refining an aluminum alloy containing one or more metal impurities having a vapor pressure higher than that of aluminum, using the apparatus according to the first aspect. The melt of the aluminum alloy heated and held at a predetermined temperature in the melt-holding furnace is supplied through a conduit into a decompression processing container whose pressure is reduced by an exhaust means, and the amount of the melt supplied from the conduit is controlled by the holding furnace. The melt that is controlled by the gas pressurizer that pressurizes the space and is supplied from the conduit into the depressurization processing container is sprayed with the inert gas heated from the inert gas supply pipe to the high temperature inert gas. And granulate,
Metal impurities are evaporated from the granular melt in the decompression treatment container, metal impurity vapor around the granular melt is removed by the flow of the inert gas, and the evaporated metal impurities are sucked by the discharge means. Then, the metal impurities are collected in a metal impurity recovery chamber arranged between the depressurization processing container and the discharging means, and the granular melt after evaporation of the metal impurities is dropped and stored in a melt storage tank inside and under the depressurization processing container. The stored melt is pumped out from a portion of the melt storage tank projecting from the decompression processing container.

According to the method of the present invention, a high temperature inert gas is blown in a high temperature decompression treatment vessel to an aluminum alloy melt containing a metal impurity having a vapor pressure higher than that of aluminum, which is capable of being vaporized. The material is granulated to increase the surface area, and the granular melt is exposed to high temperature and reduced pressure to evaporate the metal impurities from the granular melt, and further to evaporate the metal impurities around the granular melt, The flow of the inert gas removes from the periphery of the granular melt to reduce the partial pressure of metal impurities around the granular melt, thereby attempting to efficiently remove metal impurities with high vapor pressure in the aluminum alloy melt. It is a thing.

In the method of the present invention, the higher the temperature of the melt supplied from the conduit, the more finely it is granulated by spraying with an inert gas. Further, the finer the particulate melt is and the higher the temperature is, the more the evaporation of metal impurities is promoted. Therefore, the inside of the decompression processing container and the inert gas are heated to a high temperature to prevent the temperature of the melt from decreasing. As the inert gas, N ₂ gas, Ar gas, or any inert gas that does not oxidize aluminum is used.

[0010]

In the present invention, since the gas pressurizer for pressurizing the space inside the melt holding furnace is used to supply the melt from the melt holding furnace to the depressurization processing container, the amount of the melt supplied can be controlled accurately. it can. Further, means for granulating the melt supplied into the depressurization processing container is equipped with an inert gas supply pipe at the opening end of the conduit inside the depressurization processing container, the opening end of which is close to the opening end of the conduit. The melt is finely granulated. In addition, since the inert gas heater is arranged in the middle of the inert gas supply pipe, the inert gas can be heated, and since the heater is embedded in the side wall of the depressurization processing container, It is possible to prevent the temperature of the granular melt from being lowered, and thus to accelerate the evaporation of metal impurities. Further, a melt storage tank in which the granular melt is stored is located in the lower portion of the depressurization processing container, and at least a part thereof projects from the depressurization processing container through the lower side of the side wall portion where the lower end of the depressurization processing container is opened. Since it is installed in the room, the melt can be easily pumped out during the operation. Further, by storing the melted material at a predetermined height in the storage tank, the inside of the decompression processing container can be liquid-sealed.

[0011]

EXAMPLES The present invention will be described in detail below with reference to examples. Example 1 FIG. 1 is a side sectional view showing an example of a refining apparatus of the present invention. Reference numeral 1 is a melt of an aluminum alloy, 2 is a melt holding furnace for holding the melt, and 3 is a depressurization treatment container for granulating the melt under reduced pressure to evaporate metal impurities. Two melt holding furnaces 2 each holding a melt 1 of an aluminum alloy are arranged in parallel on a decompression processing container 3. A conduit 4 for supplying the melt in the holding furnace into the depressurization processing container is attached between the melt holding furnace 2 and the depressurization processing container 3.
The supply amount of the melt 1 is controlled by a gas pressurizer 5 that pressurizes the space inside the holding furnace 2 installed in the holding furnace 2. An inert gas supply pipe 6 is arranged close to the open end of the conduit 4 in the decompression treatment container 3 with its open end facing the open end of the conduit 4. An inert gas heater 7 is arranged in the middle of the inert gas supply pipe 6. Further, a heater 17 is embedded in the side wall of the decompression treatment container 3 like the melt holding furnace, and the melt can be held at a high temperature together with the inert gas heater 7.

A metal impurity recovery chamber 10 for recovering metal impurities evaporated from the granular melt 9 is arranged in a communication hole 8 provided on one side wall of the decompression treatment container 3, and the recovery chamber 10 has The exhaust pump 12 is attached with the filter 11 interposed therebetween. The exhaust pump 12 also serves to reduce the pressure inside the pressure reduction processing container 3. A melt storage tank 13 that stores a melt after evaporation of metal impurities is arranged below the decompression processing container 3. A part of the storage tank 13 is a side wall portion in which the lower end of the decompression processing container 3 is opened.
It is provided so as to protrude from the decompression processing container 3 through the lower side of 14. By storing the melt 21 at a predetermined height in the storage tank 13, the inside of the depressurization processing container 3 is sealed from the outside. A partition wall 15 is provided at the top and bottom in the center of the decompression processing container 3. The partition wall 15 increases the flow distance of the inert gas in the decompression processing container 3 to enhance the effect of removing the vapor of metal impurities around the granular melt 9. An opening hole 16 is provided in the center of the partition wall 15 and communicates with the exhaust pump 12.

Next, using the device of the present invention shown in FIG.
JIS-3003 alloy core with 2% Zn added and JIS-4043 alloy clad aluminum composite material for tubes (Zn
600 kg was smelted (concentration: 1.5%). The composite waste was heated and melted in a holding furnace and held at a temperature of 1073K or 1173K. Next, the melt in the holding furnace was supplied into the depressurization treatment container through a conduit. The melt feed rate is 100 kg
The pressure in the holding furnace was controlled by a gas pressurizer so that the pressure became / h. The melt supplied through the conduit was granulated by spraying an inert gas. The inert gas is heated in the gas heating chamber.
What was heated to 600 ° C was sprayed from an inert gas pipe. The inside of the decompression processing container was decompressed by an exhaust pump.
The pressure, temperature, and spray amount of the inert gas in the depressurization processing container were variously changed. The raw material was supplied to the two holding furnaces alternately, and the pressure reduction treatment was continuously performed.

The metal impurities evaporated from the melt were recovered in the recovery chamber. Also, the granular melt after evaporation of metal impurities is dropped and stored in the melt storage tank in the lower part of the depressurization processing container,
It was pumped out from the storage tank portion protruding from the depressurization processing container. The Al-1.5% Zn alloy melt was previously put into the storage tank before the refining was started until the lower end of the side wall of the depressurization container was submerged, thereby liquid-sealing the inside of the depressurization container. For comparison,
With the conventional apparatus shown in FIG. 2, aluminum composite scrap having the same composition was refined.

In order to know the refining effect, the melt was periodically sampled from the portion protruding from the decompression treatment container of the melt storage tank to quantitatively analyze Zn. Since the Al-1.5% Zn alloy melt was put in the melt storage tank before the depressurization treatment was started, the analysis value of Zn decreased with time, but became constant after 1 to 2 hours. Therefore, the refining effect was examined by obtaining the Zn removal rates 3 hours and 5 hours after the start of the pressure reduction treatment. Z
The n removal rate a was calculated by the formula a = [(1.5−b) /1.5] × 100 (where b is the analysis value of Zn). The particle size of the granular melt was determined by conducting a preliminary experiment by partially modifying the refining device so that the granular melt could be collected after solidification, and measuring the obtained solid phase particle size. The results are shown in Table 1.

[0016]

[Table 1] Device used: The device of the present invention shown in FIG. 1 and the conventional device shown in FIG.

As is clear from Table 1, the products of the present invention (No.
1 to 5) had a high Zn removal rate. This is because the inert gas that has granulated the melt passes through the space between the granular melts in the depressurization treatment vessel while Zn around the granular melts is formed.
This is because the vapor was removed and the Zn partial pressure around the granular melt was lowered to promote the evaporation of Zn inside the granular melt. In contrast, the comparative examples (Nos. 6 and 7) had low removal rates. This is because the inert gas was not flowed in, and the Zn vapor covered the periphery of the granular melt and the evaporation rate of Zn decreased.

Although the refining of the tube waste of the aluminum radiator containing Zn has been described above, the present invention can be applied to other aluminum product scraps and the alloy elements contained therein are Zn, Mg, Pb, etc. If the element has a high vapor pressure, the same effect can be obtained.

[0019]

As described above, according to the present invention, Zn, M
Since an aluminum alloy containing an alloy element having a vapor pressure higher than that of aluminum such as g and Pb can be efficiently removed, a remarkable effect is industrially achieved.

[Brief description of drawings]

FIG. 1 is a side sectional view showing an embodiment of a refining device of the present invention.

FIG. 2 is a perspective view of a conventional refining device.

[Explanation of symbols]

 1,21 Melt of aluminum alloy 2 Melt holding furnace 3 Decompression treatment vessel 4 Melt supply conduit 5 Gas pressurizer 6 Inert gas supply pipe 7 Inert gas heater 8 Communication hole 9 Granular melt 10 Metal impurity recovery chamber 11 Filter 12 Exhaust pump 13 Melt storage tank 14 Side wall with open lower end 15 Partition wall 16 Open hole 17 Heater 31,38 Buffer container 32 Melt pump 33 Ascending pipe 34 Vacuum processing container 35 Mist-like melt 36 Condenser 37 Descent Tube 39 melting furnace

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Koichi Ohara 2-6-1, Marunouchi, Chiyoda-ku, Tokyo Furukawa Electric Co., Ltd.

Claims (2)

[Claims] 1. A refining device for an aluminum alloy having a vapor pressure higher than that of aluminum and containing one or more kinds of metal impurities, wherein the melt holding furnace holds a melt of the aluminum alloy, and the melt is depressurized. A reduced pressure processing container for, a conduit that serves as a passage for the melt from the melt holding furnace to the reduced pressure processing container,
A melt supply means for supplying the melt in the holding furnace into the reduced pressure processing container, a granulating means for granulating the melt supplied in the reduced pressure processing container, and the inside of the reduced pressure processing container. Exhaust means for degassing and discharging metal impurities evaporated from the granulated melt in the depressurization processing container, and recovering metal impurities evaporated from the melt disposed between the depressurization processing container and the exhaust means. A refining apparatus for an aluminum alloy comprising a metal impurity recovery chamber for carrying out, a melt storage tank for storing the melt after the metal impurities are evaporated,
The melt supply means comprises a gas pressurizer for pressurizing the space inside the melt holding furnace, and the granulation means has an inert gas supply pipe at the open end of the conduit inside the depressurization processing container, and the open end is at the open end. It is installed in close proximity to the open end of the conduit, an inert gas heater is arranged in the middle of the inert gas supply pipe, and a heating element is embedded in the wall portion of the decompression processing container. The melt storage tank is provided in a lower portion of the decompression processing container, at least a part of which is provided so as to project from the decompression processing container through a lower side of a side wall portion where a lower end of the decompression processing container is opened. Aluminum alloy refining equipment characterized by 2. A method for refining an aluminum alloy containing one or more metal impurities having a vapor pressure higher than that of aluminum by using the apparatus according to claim 1, wherein the temperature is set to a predetermined temperature in a melt holding furnace. The heat-held aluminum alloy melt is supplied through a conduit into a decompression container whose pressure is reduced by exhaust means, and the amount of the melt supplied from the conduit is controlled by a gas pressurizer that pressurizes the holding furnace space. Then, the melt supplied from the conduit into the decompression processing container is granulated by spraying an inert gas heated at a high temperature by an inert gas heater from an inert gas supply pipe to the decompression processing container. In the inside, the metal impurities are evaporated from the granular melt, the metal impurity vapor around the granular melt is removed by the flow of the inert gas, the evaporated metal impurities are sucked by the discharge means, and the pressure reduction treatment is performed. container And a discharging means for collecting in the metal impurity collecting chamber, the granular melt after evaporation of the metal impurities is dropped and stored in the melt storage tank in the lower part of the depressurization processing container, and the stored melt is melted. A method for refining an aluminum alloy, which comprises pumping a product from a portion of the melt storage tank projecting from a decompression processing container.