JP2002213877A - Metal melting apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a metal melting apparatus, capable of supplying high quality metal melt by surely removing any impurity in the metal melt. SOLUTION: Metal melt is obtained by melting solid metal in a melting furnace chamber 11. Any impurity in the metal melt is separated physically or chemically in a processing chamber 13. A settlement passage 14 is provided between the processing chamber 13 and a sectioning-out chamber 15. By introducing the metal melt into the suction-out chamber 15, after the passage via the settlement passage 14 time required for settlement of the metal melt processed in the processing chamber 13 is secured to secure separation of impurities from the metal melt.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal melting apparatus for melting a metal and obtaining a molten metal from which impurities have been removed.

[0002]

2. Description of the Related Art An apparatus for melting metals, particularly aluminum alloys, includes a melting furnace chamber for melting solid metal, and a pumping chamber for pumping molten metal, and is provided between the melting furnace chamber and the pumping chamber. It is generally known to provide a processing chamber for removing impurities in a molten metal. Examples of the impurity component in the molten aluminum alloy include various mixed metals, oxides, hydrogen, and the like. In the processing chamber, for example, by blowing an inert gas into the molten metal to generate an infinite number of bubbles (bubbling), hydrogen is taken in the inert gas bubbles, and inclusions are formed at the interface of the inert gas bubbles. A trapping process is performed such as capturing and separating these impurity components by floating them on the surface of the molten metal together with bubbles.

Further, as an improvement of such a conventional melting apparatus, there is an apparatus disclosed in, for example, Japanese Patent Application Laid-Open No. 7-146073. In this apparatus, a pool chamber and a holding chamber are secured between a melting chamber (melting furnace chamber) and a bubbling treatment chamber, and a weir is provided to separate the upstream pool chamber and the downstream holding chamber. . Then, the dust and the like melted together with the metal lump by the weir are settled at the bottom of the pool room to remove impurities in advance.

[0004]

However, in the weir disclosed in the above-mentioned publication, it is not possible to block impurities having a specific gravity equal to that of the molten aluminum alloy or buoyant impurities lighter than the same. In addition, it is necessary to get over the weir in order for the molten metal to move from the pool room to the holding room,
At that time, the opportunity (or contact area) of the aluminum alloy melt to contact with air increases, which may rather promote the formation of oxides. For this reason, it is not effective to remove impurities before the bubbling process by providing the pool room and the weir for partitioning the pool room upstream of the bubbling process chamber as described above.

An object of the present invention is to provide a metal melting apparatus capable of supplying a high-quality metal melt by reliably removing impurities in the metal melt.

[0006]

According to the first aspect of the present invention, there is provided a metal melting apparatus in which a solid metal is melted to form a molten metal, and impurities in the molten metal are separated by physical or chemical treatment. And a pumping chamber for pumping the molten metal having been subjected to the impurity separation treatment, and a processing chamber provided between the processing chamber and the pumping chamber, wherein the processing of the molten metal processed in the processing chamber is performed. And a calming passage for guiding the molten metal to the pumping chamber while securing time for calming.

According to this structure, since the settling passage is provided between the processing chamber and the pumping chamber, the molten metal processed in the processing chamber is settled before the molten metal reaches the pumping chamber. Time (residence time) is secured. That is, while the molten metal passes through the settling passage for a predetermined period of time, by being settled, impurities that have not been completely separated and removed by physical or chemical treatment in the processing chamber are separated from the target metal. Is settled at the bottom of the settling passage or floated on the surface of the molten metal (the surface of the molten metal) based on the difference in specific gravity, and is clearly separated from the target metal. For this reason, in the pumping chamber located at the outlet of the settling passage, it is possible to obtain a high-purity molten metal.

The physical treatment for separating impurities in the molten metal in the treatment chamber includes bubbling of an inert gas and rotary degassing by using mechanical stirring together with bubbling of the inert gas. can give. As a chemical treatment for separating impurities in the molten metal in the treatment chamber, there is a supply of a flux (separation aid) into the molten metal. In particular, when a chemical treatment with a flux is performed, impurity separation by allowing the molten metal to settle for a predetermined time in the settling passage becomes effective.

According to a second aspect of the present invention, in the metal melting apparatus according to the first aspect, a first partition is provided between the processing chamber and the settling passage. First to allow the molten metal at the bottom of the chamber to enter the settling passage
Is provided.

According to this configuration, the movement of the molten metal from the processing chamber to the settling passage is performed through the first communication port, and the processing chamber is formed by the first partition at least at the level (height) of the molten metal surface. And the calming passage are separated. Therefore, the impurities floating on the surface of the molten metal in the processing chamber are prevented from entering the settling passage by the first partition, and only the molten metal containing no floating impurities enters the settling passage via the first communication port. can do. Further, even in a situation where the molten metal in the processing chamber flows violently due to the physical processing in the processing chamber, the first partition wall prevents the influence of such flow from reaching the settling passage and setstle down. Keep calm in the passage.

According to a third aspect of the present invention, in the metal melting apparatus according to the first or second aspect, a second partition is provided between the settling passage and the pumping chamber, and the second partition is provided with the second partition. A second communication port is provided for allowing the molten metal located between the bottom surface of the settling passage and the molten metal surface to enter the pumping chamber.

According to this configuration, the second communication port for communicating the calming passage with the pumping chamber is located between the bottom surface of the calming passage and the molten metal surface. Therefore, floating impurities are prevented from being pumped into the chamber by the upper half portion of the second partition located above the second communication port, and are located below the second communication port. The lower half of the second partition prevents settling impurities from pumping into the chamber. Therefore, only high-purity molten metal containing neither floating impurities nor settling impurities is supplied to the pumping chamber via the second communication port.

According to a fourth aspect of the present invention, in the metal melting apparatus according to any one of the first to third aspects, the calming passage is provided with a heat retaining means.

According to this structure, the temperature keeping means prevents the temperature of the molten metal from lowering, maintains the low viscosity of the molten metal, promotes the floating and / or settling of the impurities, and promotes the separation of the impurities utilizing the difference in specific gravity. Or smoothed.

According to a fifth aspect of the present invention, in the metal melting apparatus according to any one of the first to fourth aspects, the processing chamber is provided with a means for blowing an inert gas into the molten metal. It is characterized by being.

According to this configuration, the gas component and other impurities dissolved in the molten metal are trapped by the bubbling action of the inert gas blown into the molten metal, and removed together with the inert gas to the outside of the molten metal.

According to a sixth aspect of the present invention, in the metal melting apparatus according to the fifth aspect, a cover is provided above the processing chamber and the calming passage to guide gas in the processing chamber to the calming passage. It is characterized by the following.

According to this configuration, the gas phase between the cover provided above the processing chamber and the settling passage and the molten metal surface is:
The chamber is filled with a gas (mainly an inert gas) generated in the processing chamber, so that entry of air from the outside is hindered. For this reason, the gas phase immediately above the molten metal surface becomes a non-oxygen atmosphere, thereby preventing oxidation of the molten metal and maintaining the quality of the molten metal.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is embodied in a metal melting apparatus for an aluminum alloy will be described below.
As shown in FIGS. 1 to 3, the metal melting apparatus includes a melting furnace chamber 1.
1, a holding chamber 12, a processing chamber 13, a settling passage 14, and a pumping chamber 15.

The melting furnace chamber 11 is a furnace chamber or area for melting (melting) an aluminum alloy ingot (not shown) as a solid metal using a heat source (not shown) such as a gas burner, and extends in a vertical direction. A flue 11a is provided.
The aluminum alloy melted in the melting furnace chamber 11 flows into the storage tank S as a molten metal. The storage tank S located on the downstream side of the melting furnace chamber 11 is separated from the holding chamber 1 by the partition wall 21.
2 and other areas (the processing chamber 13, the settling passage 14, and the pumping chamber 15). However, partition wall 2
The lower end of 1 does not reach the bottom of the storage tank S, and the molten metal can move from the holding chamber 12 to the processing chamber 13 through the lower side of the partition wall 21.

The holding chamber 12 is located immediately downstream of the melting furnace chamber 11 and temporarily holds or stores the molten metal from the melting furnace chamber 11 in a high temperature state. In that sense, this holding room 1
The processing chamber 13, the settling passage 14, and the pumping chamber 15 located on the downstream side of 2 can also be regarded as a part of the holding chamber. Processing chamber 13, settling passage 14 and pumping chamber 15
Are a first partition (22, 23) and a second partition (2
4, 25).

As shown in FIG. 4, the first partition provided between the processing chamber 13 and the settling passage 14 is composed of a first large partition plate 22 and a first small partition plate 23. I have. First
The large partition plate 22 is fixed to the bottom wall and the left side wall of the storage tank S, and secures a gap C1 between the large partition plate 22 and the right side wall of the storage tank S. Then, a first small partition plate 23 is detachably fitted into the gap C1 so as to fill the upper end portion and the central portion of the gap C1, and the processing chamber 13 is provided at the lower right corner of the first partition wall. A first communication port 31 for communicating with the calming passage 14 is provided. This first communication port 31 is
It is located below the molten metal surface L when the apparatus is used.

The second partition provided between the settling passage 14 and the pumping chamber 15 is composed of a second large partition plate 24 and a second small partition plate 25, as shown in FIG. I have.
The second large partition plate 24 is fixed to the bottom wall, the right side wall, and the lower end of the left side wall of the storage tank S, and secures a gap C2 between the second large partition plate 24 and the left side wall of the storage tank S. And the gap C
A second small partition plate 25 is removably fitted into the gap C2 so as to fill the upper end of the second partition wall. A second communication port 32 to be made is secured. This second communication port 32 is also located below the molten metal surface L when the apparatus is used.

As described above, the settling passage 14 is defined between the processing chamber 13 and the pumping chamber 15 by the first and second partition walls. The molten metal enters the settling passage 14 from the processing chamber 13 via the first communication port 31, and further enters the pumping chamber 15 from the settling passage 14 via the second communication port 32. .

The processing chamber 13 is an area for floating and separating impurities in the molten metal by physical and / or chemical treatment. For this reason, various processing means for physical or chemical processing are provided in the processing chamber 13. For example, as the physical processing means, there is a rotary degassing device 33 (shown by a two-dot chain line in FIGS. 1 to 3). Rotary degasser 3
Reference numeral 3 includes a mechanical stirring mechanism including a rotary shaft and a rotor (impeller), and a gas blowing mechanism provided in the mechanical stirring mechanism. By bubbling by blowing an inert gas (for example, nitrogen gas) into the molten metal through the gas blowing mechanism, gas components such as hydrogen gas and low specific gravity impurities mixed into the molten metal are floated and separated from the molten metal. be able to. At this time, the mechanical stirring mechanism works to make the inert gas bubbles finer by the stirring action and to make the molten metal flow violently, thereby promoting gas-liquid contact and enhancing the degassing effect and the like. In addition, as another physical processing means, there is a gas blowing device (not shown) using a lance pipe. A lance pipe is a conduit in which the tip of the pipe is bent into a substantially L-shape and has a number of small holes formed therein, and is useful for achieving bubbling without mechanical forced agitation.

Even if gas components in the molten metal can be removed by bubbling inert gas and mechanically forced stirring by the rotary degassing device 33, there are cases where other impurities cannot be effectively floated and separated. is there. In such a case, it is preferable to perform a chemical treatment by blowing a flux into the molten metal in the processing chamber 13. Flux is an auxiliary agent added to remove impurities when dissolving a metal.The flux forms a compound phase different from the target metal phase by combining with the impurities, and the impurities are removed by separating both phases. Refers to an additive aid that makes it possible. Examples of the flux include chlorides such as calcium chloride, magnesium chloride, sodium chloride, and potassium chloride, as well as fluorides, bromides, carbonates, sulfates, nitrates, and mixtures containing these as main components. Generally, the flux is powdery, and the inert gas flowing through the gas blowing mechanism is blown into the molten metal as a carrier gas.

The pumping chamber 15 is located at the most downstream of the metal melting apparatus, and is an area for storing the molten metal that has passed through the settling passage 14. The upper part of the pumping chamber 15 is open (or can be opened), from which the molten metal can be pumped out with a ladle or the like and used for casting or the like.

The settling passage 14 connecting the processing chamber 13 and the pumping chamber 15 is provided with a time (residence time) for the metal melt processed in the processing chamber 13 to calm down (residence time). It is a passage for guiding. The necessity of such a sedimentation passage 14 is that completeness is difficult to be achieved only by impurity separation in the processing chamber 13. That is, in the processing chamber 13, the molten metal always flows violently due to the physical action of bubbling and mechanical stirring. Therefore, the gas component can be effectively separated, but on the other hand, an impurity component having a small specific gravity difference from the molten aluminum alloy is rather involved to promote uniform dispersion. Therefore, in order to clearly separate (float or settle) even such an impurity component having a small difference in specific gravity, it is necessary to take a certain period of time to keep the impurity component in a quiet state. There is a meaning of the calming passage 14 disposed between them.

The size (capacity) of the calming passage 14 is preferably in the range of 1/4 to 1/3 of the amount of molten metal used in the pumping chamber 15 (amount of molten metal drawn out per unit time). If the size of the settling passage 14 is less than 1/4 of the amount of the molten metal used, the time (residence time) for the molten metal to pass through the settling passage 14 is insufficient, and the impurity components that cannot be separated in the processing chamber 13 are removed. There is a possibility that the meaning of the sedimentation passage 14 of separating may not be sufficiently exhibited. On the other hand, if the size of the settling passage 14 exceeds 1/3 of the used amount of the molten metal, the time (residence time) for the molten metal to pass through the settling passage 14 becomes long, and the temperature of the molten metal is excessively lowered, and the fluidity and There is a possibility that the workability of pumping in the pumping chamber 15 may be reduced. 1/4 to 1 /
With the range of 3, it is possible to effectively exhibit the original function of the calming passage 14 while preventing the occurrence of secondary adverse effects.

It is preferable to provide a heat retaining means 34 (shown by a dashed line in FIGS. 1 to 3) in the settling passage 14.
Examples of the heat retaining means 34 include an electric heater and a gas burner. By providing the heat retaining means 34, it is possible to prevent a decrease in the temperature of the molten metal in the settling passage 14 and a variation in the temperature distribution in the passage. In addition, the provision of the heat retaining means 34 sufficiently lowers the viscosity of the molten metal and promotes floating or settling of impurities.

Further, as shown in FIG. 1 and FIGS.
In a region extending from the processing chamber 13 to the pumping chamber 15, covers 41 to 44 are provided to cover the area above the processing chamber 13. That is,
Two covers 41 and 42 are arranged above the processing chamber 13, and two covers 43 and 44 are arranged above a part of the settling passage 14 and the pumping chamber 15. These four covers 41 to 44 are located at a predetermined height from the molten metal surface L, and form a kind of gas flow path with the molten metal surface L. Through this gas flow path, the gas generated in the processing chamber 13 (and the gas remaining in the gas phase portion of the processing chamber 13) is led to the settling passage 14, and the gas is released above the pumping chamber 15. . Therefore, the gas generated in the processing chamber 13 is filled by the covers 41 to 44 at least in the gas phase area above the processing chamber 13 and the gas phase area above the quiet passage 14.
Air (oxygen-containing gas) from outside is prevented from entering these gas phase regions.

Next, the most preferable method of using the metal melting apparatus shown in FIGS. 1 to 5 and advantages in that case will be described. In the most preferred use example, the rotary degassing device 33 as a physical processing means is installed in the processing chamber 13. In addition, inert gas (eg:
A flux (eg, calcium chloride) is blown into the molten metal in the processing chamber 13 together with nitrogen gas), and a chemical treatment is also used.

According to this usage example, the gas component such as hydrogen gas dissolved in the aluminum alloy melt moved from the holding chamber 12 to the processing chamber 13 is subjected to the bubbling action of the inert gas and the stirring action of the impeller. It floats on the molten metal surface L and is discharged into the gas phase region of the processing chamber 13. In addition, in the processing chamber 13, the flux blown into the molten metal reacts with impurity components such as iron to generate an impurity compound. Many of the impure compounds generated in this way have a relatively lower specific gravity than the aluminum alloy, and thus float on the molten metal surface L. At this time, the respective actions of the bubbling and stirring promote the floating of the impurity compound. Thus, in the processing chamber 13, the gas components in the molten metal are degassed, and many of the impurity components are floated and separated on the molten metal surface L as impurity compounds. The impure compounds floating on the molten metal surface L are blocked by the first partition walls (22, 23) and do not enter the settling passage. Thus, the metal melt from which gas components and impurities have been removed to some extent accumulates at the bottom of the processing chamber 13.

The molten metal collected at the bottom of the processing chamber 13 enters the calming passage 14 through the first communication port 31. The molten metal flows from the first communication port 31 to the second communication port 32.
It takes a certain amount of time to reach the temperature, depending on the amount of molten metal used in the pumping chamber 15. In other words, the molten metal that has been exposed to the intense flow in the processing chamber 13 is also settled in the settling passage 14 separated by the first partition walls (22, 23).
Is relatively quiet for a predetermined residence time (eg, 15 minutes or more). For this reason, before reaching the second communication port 32, impurity components having a small difference in specific gravity from the aluminum alloy melt and impurity compounds derived from the flux that cannot be completely separated in the processing chamber 13 are removed from the settling passage 14. It is almost completely separated in such a manner that it floats on the molten metal surface L or sinks at the bottom of the settling passage 14. Calm passage 14
The impurity components and the impurity compounds floating on the molten metal surface L of the second metal are blocked by the upper half of the second partition (24, 25) (part of the partition above the second communication port 32), and the pumping chamber 1
You will not enter 5. In addition, impurity components and the like settled at the bottom of the settling passage 14 are also blocked by the lower half of the second partition (partition portion below the second communication port 32), and do not enter the pumping chamber 15. . Thus, the quiet passage 1
A high-purity aluminum alloy melt stays at a substantially intermediate position between the bottom surface of 4 and the metal melt surface L, and only such a metal melt is supplied to the pumping chamber 15 through the second communication port 32. Therefore, the molten metal in the pumping chamber 15 is kept in a high purity state.

The gas blown out of the molten metal in the processing chamber 13 into the gas phase is a mixed gas of an inert gas and a mixed gas component (mainly hydrogen gas). The mixed gas is guided from the gas phase region of the processing chamber 13 to the gas phase region of the quiet passage 14 by the covers 41 to 44 described above, and is further discharged to the gas phase region above the pumping chamber 15. The mixed gas is constantly discharged from the processing chamber 13 toward the pumping chamber 15, so that the oxygen-containing air flows into the processing chamber 13 and the quiet passage 14.
Cannot enter the gas phase region, and the gas phase region is always in a non-oxygen atmosphere. Therefore, the molten aluminum alloy in the processing chamber 13 and the quiet passage 14 is not oxidized by oxygen in the gas phase. In a non-oxygen atmosphere, the processing chamber 1
Hydrogen gas in the gaseous phase region 3 and in the quiet passage 14 is ignited by the high temperature of the molten metal and does not generate steam.

(Modification) The above embodiment may be modified as follows. In the above embodiment, the covers 41 to 44 are provided, but these covers need not be provided.

The first partition (or the second partition) is composed of two large and small partition plates 22, 23 (or 24, 25), but a single plate with a hole for the communication port 31 (or 32). May be configured.

The first communication port 31 or the second communication port 32
(For example, a filter made of porous ceramics) for removing impurity components may be arranged at the position.

[0039]

As described in detail above, according to the metal melting apparatus described in each claim, the provision of the calming passage between the processing chamber and the pumping chamber reduces impurities in the molten metal. High quality molten metal can be supplied by reliably removing.

[Brief description of the drawings]

FIG. 1 is a plan view of a metal melting apparatus.

FIG. 2 is a plan view showing a state where a cover is removed from the apparatus of FIG. 1;

FIG. 3 is a schematic cross-sectional view taken along line AA of FIG.

FIG. 4 is a sectional view taken along line BB in FIG. 1;

FIG. 5 is a sectional view taken along line CC in FIG. 1;

[Description of Signs] 11: melting furnace chamber, 12: holding chamber, 13: processing chamber, 14 ...
Settling passage, 15: pumping chamber, 22: first large partition plate,
23: first small partition plate (22, 23 constitutes a first partition), 24: second large partition plate, 25: second small partition plate (24, 25 constitutes a second partition) 31) First communication port, 32 ... Second communication port, 33 ... Rotary degasser (physical processing means), 34 ... Heat retaining means, 41-44 ... Cover, L ... Metal melt surface.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4K001 AA02 BA23 EA03 FA14 GB03 GB05 4K045 AA03 BA03 RA12 RB12 RB16 RB29

Claims (6)

[Claims] 1. A melting furnace chamber for melting a metal into a molten metal, a treatment chamber for separating impurities in the molten metal by physical or chemical treatment, and a molten metal subjected to an impurity separation treatment And a pumping chamber for pumping the molten metal, which is provided between the processing chamber and the pumping chamber and secures time for calming down the molten metal processed in the processing chamber. A metal dissolving device, comprising: a settling passage for guiding the liquid to the metal. 2. A first partition wall is provided between the processing chamber and the settling passage, and the first partition wall allows a molten metal at the bottom of the processing chamber to enter the settling passage. 2. The metal melting apparatus according to claim 1, wherein one communication port is provided. 3. A second partition wall is provided between the settling passage and the pumping chamber, and the second partition wall is provided with a metal melt located between the bottom surface of the settle passage and the metal melt surface. The metal melting device according to claim 1, further comprising a second communication port that allows entry into the pumping chamber. 4. The metal melting apparatus according to claim 1, wherein the calming passage is provided with a heat retaining means. 5. The metal melting apparatus according to claim 1, wherein a means for blowing an inert gas into the molten metal is provided in the processing chamber. 6. The metal melting apparatus according to claim 5, wherein a cover is provided above the processing chamber and the calming passage to guide gas in the processing chamber to the calming passage.