JPH06287653A - Method for melting light alloy chip and melting furnace therefor - Google Patents

Abstract

PURPOSE:To provide a method for melting light alloy chips and a melting furnace therefor which has good yield and low fuel cost and can prolong the service life of the furnace. CONSTITUTION:In the melting furnace A for light metal chip wherein the light alloy chips are charged into the molten metal in the furnace and also, the molten metal surface S is heated with a heating burner 5 so as to melt light alloy chips, a heat resistant stoke 2 is disposed so as to dip into the molten metal at the lower end part thereof from the upper part of the furnace. A light alloy chip charging hole 2b is arranged at the inner part of the stoke 2, and also, the heating burner 5 is disposed at the outer part of the stoke 2 so that a flame injecting hole directs the molten metal surface S.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a melting method and melting furnace for light alloy chips for recycling light alloy chips generated as scrap.

[0002]

2. Description of the Related Art In recent years, from the viewpoint of resource saving, attempts have been made to melt, recycle and utilize light alloy chips generated as scraps in processing such as cutting.

As a melting method (melting method) for reproducing the light alloy chips, there are a reverberatory furnace method and a crucible method.

The above-mentioned reverberatory furnace system is carried out by blowing a flame of a heating burner onto the surface of the molten metal in the furnace to heat the molten metal and putting light alloy chips into the molten metal. When the reverberatory furnace method is carried out, as shown in FIG. 8, a heating chamber for heating the molten metal surface S by the heating burner 5 in order to promote the stirring of the molten metal and make the temperature of the molten metal uniform.
A melting furnace A ′ having a stirring section 21 for rotating and stirring the stirring blade 3 immersed in the molten metal by a drive shaft 4 extending from above is used on the side of 20.

Further, in the crucible system, as shown in FIG. 9, the bottom surface of the melting furnace body 1'containing the molten metal is heated from below by a heating burner 5 and light alloy chips are put into the furnace. It is carried out. When the crucible method is carried out, in order to promote the stirring of the molten metal and make the temperature of the molten metal uniform, the drive shaft 4 extended from above is provided.
A melting furnace in which a stirring blade 3 which is rotated by is provided in the molten metal is used.

In addition to the above system, there is also a system (not shown) in which a heating burner is provided inside a ceramic tube immersed in a molten metal (referred to as an immersion burner system in this specification).

[0007]

However, in the case of the above-mentioned reverberatory furnace system, when the light alloy chips are put into the molten metal, the flame of the heating burner hits the light alloy chips, so that the light alloy chips are oxidized. Metal loss occurred,
As a result, the yield is reduced. Further, when the amount of light alloy chips charged is temporarily increased, the temperature of the stirring section separated from the heating chamber is lowered, and as a result, the viscosity of the molten metal is increased and the life of the stirring blade is shortened.

Further, in the case of the crucible system, the light alloy tip does not come into direct contact with the flame, so that metal loss does not occur, so that the yield is good, but the molten metal is indirectly heated, so that the fuel consumption deteriorates. Further, since the bottom surface is heated at a high temperature, the life of the crucible itself is short and the crucible replacement frequency is high.

Further, in the case of the above-mentioned immersion burner system, since the flame injection port of the heating burner is provided so as to be immersed in the molten metal, although the fuel consumption is good, each portion of the ceramic tube immersed in the molten metal is Due to the large temperature difference, the ceramic tube needs to be replaced in a relatively short time.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a melting method and melting furnace for light alloy chips which has a high yield and good fuel consumption and can prolong the life of the furnace.

[0011]

A method of melting a light alloy chip according to the present invention is to melt a light alloy chip by charging the light alloy chip into a molten metal in a furnace and heating the surface of the molten metal with a heating burner. In the melting method, a light alloy tip is put inside the heat-resistant stalk provided so that the lower end is immersed in the melt from above the furnace, and the melt surface outside the stalk is heated and melted by a heating burner. It is characterized by

The light alloy chip melting furnace according to the present invention is constructed such that the light alloy chips are put into the molten metal in the furnace and the surface of the molten metal is heated by a heating burner to melt the light alloy chips. In a light alloy chip melting furnace, a heat-resistant stalk is arranged so that the lower end is immersed in the molten metal from above the furnace, and a light alloy chip inlet is provided inside the stalk and a flame injection port is located outside the stalk. Is characterized in that a heating burner is arranged so as to face the surface of the molten metal.

[0013]

According to the method for melting light alloy chips and the melting furnace according to the present invention, the molten metal is heated in the furnace by the heating burner at the outside of the stalk whose lower end is immersed in the molten metal. Since the alloy chips are put inside the stalk, the light alloy chips put in the molten metal do not directly touch the flame of the heating burner, so that the yield is improved and high fuel consumption can be obtained.
Further, since the melting furnace itself is not heated, the durability of the furnace is improved.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a partially sectional plan view showing the structure of a melting furnace for a light alloy chip (aluminum chip in this embodiment; hereinafter referred to as an aluminum chip) according to an embodiment of the present invention, and FIG. 1 is a front sectional view and FIG. 3 is a side view of FIG.

1 to 3, A is a melting furnace, 1 is a melting furnace main body whose base is formed in a circular shape in plan view, 2 is a stalk (cylindrical body) in which an inside is an aluminum chip charging port 2b, 3 Is a stirring blade, 4 is a drive shaft for rotating the stirring blade 3, 5
Is a heating burner, 6 is a ladle with the melting furnace body tilted (Fig. 4).
Reference numeral 7 is a molten metal discharge port for discharging the molten metal, and 7 is a ladle-shaped molten metal discharge port for discharging the molten metal to the outside.

As shown in FIG. 1, in the present embodiment, the stalk 2 is concentrically arranged at the center of the base of the melting furnace body 1 (referring to the circular portion of the furnace in plan view), and the lower end thereof is As shown in FIG. 2, it is arranged to be immersed in the molten metal during the melting operation. Therefore, the stalk 2 is formed of a heat-resistant material, and the smelting furnace body 1 is formed from above.
A collar portion (2a) is formed so as to be engaged with the stalk mounting hole formed in the center in a mounted state.

The stirring blade 3 is concentric with the center of the stalk 2 as shown in FIG. 1, and the upper end of the stirring blade 3 is lower than the lower end of the stalk 2 as shown in FIG. It should be located slightly below, and the upper end of the stirring blade 3 is 50 to 150 mm below the surface S of the molten metal, preferably 100 mm.
It is arranged so as to be located approximately downward. The stirring blade 3 has a predetermined rotation speed (in the case of this embodiment, approximately 10
(0 to 350 rpm), the radius of the vortex formed by stirring the molten metal is set to be equal to the diameter of the stalk 2, and the stirring blade 3 rotates a predetermined amount to cause the molten metal to stir. The pitch of the stirring blades 3 is configured so that a flow going from the upper side to the lower side is formed around the blades 3. Then, the rotation is configured to be performed by the prime mover (electric motor or the like) at the upper end of the drive shaft 4 via the drive shaft 4.

As shown in FIG. 1 or FIG. 2, an opening for disposing a heating burner 5 is provided on the wall surface 1a of the melting furnace body 1 at a position approximately in the middle of the stalk 2 in terms of height. Is formed, and the flame injection port 5a is formed in this opening with the molten metal surface S
The heating burner 5 is arranged so as to face to the side. Therefore, the heating burner 5 is located outside the stalk 2. Further, in this embodiment, the heating burner 5 has a capability of injecting a flame whose flame length is long enough to go around the outer peripheral region of the stalk 5.

As shown in FIG. 1, the molten metal discharge port 6 and the molten metal pumping port 7 are formed in the melting furnace main body 1 so as to oppose each other with the stalk 2 interposed therebetween.

Further, as shown in FIG. 1, on the wall surface 1a of the melting furnace body 1, there is provided an impurity outlet 8 for discharging impurities (slag) accumulated on the surface S of the molten metal during melting to the outside. It is provided in two places with the discharge port 6 in between. Further, at the lower part of the melting furnace main body 1, there is formed a drain port 9 used for discharging all the molten metal.

Further, the melting furnace A of this embodiment is constructed so that the melting furnace body 1 can be tilted leftward by an angle θ around the lower left end, as shown by the chain double-dashed line L in FIG. .

By the way, around the melting furnace A, as shown in FIG.
5, II which is a plan layout view of FIG.
As shown in FIG. 6 which is a view from the arrow II, and FIG. 7 which is a view from the arrow III-III, other equipment for supplying the aluminum chips and treating the molten metal is arranged. That is, in order to supply the aluminum chips into the stalk 2, a raw material supply hopper B that inputs a chip-shaped aluminum raw material, and a crusher D that processes the supply hopper B into chips of a predetermined size.
Scraper conveyor C that conveys the aluminum chips to the chamber, a centrifugal separator E that is disposed below the crusher D and that removes the liquid adhering to the aluminum chips processed to a desired size, and a screw conveyor that supplies the aluminum chips to the chamber G. F, a rotary kiln H for drying aluminum chips, a scraper conveyor I for supplying the aluminum chips and a supply chute M are arranged inside the stalk 2. Further, a pumping robot J which is arranged in the vicinity of the molten metal pumping port 7 for pumping the molten metal into the mold k by a work arm (not shown), and an ingot conveyor K in which the mold k for making an ingot is arranged in parallel on the transport surface are arranged. Has been done. Further, below the molten metal outlet 6, a ladle 10 which is a container for transporting the molten metal to the casting site is arranged. Further, a stirring blade 3 elevating device (not shown) for adjusting the vertical position of the stirring blade 3 according to the liquid level of the molten metal is connected to the drive shaft 4.

Therefore, the melting furnace A according to the present embodiment having the above-described structure acts as follows in melting the aluminum chips.

That is, the aluminum chips fed from the supply hopper B are processed by the crusher D, the centrifuge E, the rotary kiln H, etc. to remove excess liquid or the like having a certain size or less. The scraper conveyor I and the supply chute M are used to make the stalk 2 of the melting furnace A.
Supplied within. The molten metal in the stalk 2 portion of the melting furnace main body 1 forms a flow from the upper side to the lower side as shown by an arrow R in FIG. 2 by the stirring blade 3, so the aluminum chips float on the surface. Without being drawn into the molten metal promptly. At this time, no air is drawn into the molten metal.

The molten metal containing the above-mentioned charged aluminum chips is conveyed along the convection (see the arrow R in FIG. 2) around the outside of the stalk 2 of the melting furnace body 1, where the heating burner is used. The molten metal surface S is heated by 5 and heat for continuously performing the desired melting is supplied.

Therefore, the aluminum chips supplied into the stalk 2 as described above do not come into direct contact with the flame of the heating burner 5 and therefore do not oxidize.
High yield and fuel efficiency can be obtained.

Then, the aluminum chips melted as described above are taken out of the melting furnace A through the melt discharge port 6 or the melt pumping port 7 in a molten state.

When pumping out from the molten metal pumping port 7, the pumping robot J automatically pumps it to the mold k, and from the molten metal discharge port 6,
The melting furnace body 1 is tilted by a well-known lifting / lowering tilting device such as a hydraulic cylinder, so that the melting furnace main body 1 is taken out to the ladle 10 arranged below the molten metal discharge port 6.

As described above, in the melting furnace A according to this embodiment, the base portion is formed in a circular shape, the stalk 2 is arranged concentrically in the center thereof, and the stirring blade 3 is concentric in the center of the stalk 2. Since they are arranged in a shape, the aluminum chips thrown into the stalk 2 are drawn downward in the molten metal, flow through the bottom of the molten metal to the outside of the stalk 2, and rise at the portion outside this stalk 2. Then, it is heated by the heating burner 5 here. This results in highly efficient heat transfer and convection that equalizes the temperature throughout the melt. Therefore, the melting work of the aluminum chip is performed very smoothly and with a small amount of heat energy.

Further, according to the peripheral equipment including the melting furnace A according to the present embodiment, simply supplying the aluminum chips to the supply hopper B produces the aluminum chips suitable for the melting process, and the aluminum chips are fixed in the melting furnace A. Since a large amount of aluminum chips can be melted per unit time with a very small amount of manpower since it can be supplied in a quantity, the required thermal energy is low and a high yield can be obtained.

By the way, in the present embodiment, the case of the aluminum chip was explained exclusively, but it goes without saying that the same can be applied to the case of other light alloy chips.

[0033]

As described above, according to the melting method and melting furnace for aluminum chips of the present invention, the light alloy chips are melted as described above, so that the light alloy chips can be melted very efficiently. Becomes

Therefore, scrap light alloy chips which could not be used due to profitability in the past can be regenerated, which contributes to resource saving.

Further, since the melting furnace is not directly heated by the heating burner and the temperature of the molten metal in the furnace can be made uniform, the life of the melting furnace is extended as compared with the conventional one. be able to.

[Brief description of drawings]

FIG. 1 is a partially sectional plan view showing the structure of a melting furnace for a light alloy chip according to an embodiment of the present invention.

FIG. 2 is a front sectional view showing a configuration of a melting furnace for the light alloy chip of FIG.

FIG. 3 is a side view showing a configuration of a melting furnace for the light alloy chip of FIG.

FIG. 4 is a plan layout view showing the melting furnace of FIG. 1 and devices around the melting furnace.

5 is a view on arrow I-I of FIG. 4. FIG.

FIG. 6 is a view taken along the line II-II in FIG.

FIG. 7 is a view taken along the line III-III in FIG.

FIG. 8 is a front sectional view showing the structure of a conventional reverberatory furnace melting furnace.

FIG. 9 is a front sectional view showing the structure of a conventional crucible-type melting furnace.

[Explanation of symbols]

 A ... Melting furnace S ... Molten metal surface 1 ... Melting furnace main body 2 ... Stoke 2b ... Chip input port 5 ... Heating burner 5a ... Flame injection port

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Kiyotaka Yoshimura 1-56 Minamikami-Kosaka, Higashi-Osaka City, Osaka Prefecture Kosaka Combustion Furnace Works (72) Inventor Seiro Tokunaga 1-1 Kawasaki-cho, Akashi-shi, Hyogo No. 1 Kawasaki Heavy Industries, Ltd. Akashi Plant (72) Inventor Teruhiko Yoshimine 1-1 Kawasaki-cho, Akashi-shi, Hyogo Prefecture Kawasaki Heavy Industries Ltd. Akashi Plant

Claims (2)

[Claims] 1. A melting method in which light alloy chips are put into a molten metal in a furnace and the surface of the molten metal is heated by a heating burner to melt the light alloy chips, the lower end of the furnace is immersed in the molten metal. While putting the light alloy tip inside the heat resistant stalk,
A method for melting a light alloy chip, characterized in that the surface of the melt outside the stalk is heated by a heating burner to melt. 2. A light alloy chip melting furnace configured to introduce light alloy chips into a molten metal in a furnace and heat the surface of the molten metal with a heating burner to melt the light alloy chips. A heat-resistant stalk was placed so that the slag could be immersed in the molten metal, a light alloy chip inlet was provided inside the stalk, and a heating burner was placed outside the stalk so that the flame injection port faced the molten metal surface. A melting furnace for light alloy chips, characterized in that