JPS6273591A - Melted material agitator in furnace - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an in-furnace molten metal stirring device that is installed under the hearth and stirs molten metal in the furnace in a non-contact manner.

[Prior art]

Conventionally, as a non-contact type molten metal stirring device, an electromagnetic molten metal stirring device that uses a moving magnetic field to stir and move the molten metal in a furnace has been developed. However, this type of stirring device is mainly intended to uniformly heat and homogenize the molten metal, and has a small capacity that allows the surface of the molten metal to move slightly, and the starting point of movement of the molten metal is also limited to a fixed position. Therefore, the molten metal and the remaining lumps are mixed together and the molten metal existing in the furnace falls during the latter half of the period, which is inappropriate for promoting melting and streamlining refining and slag removal. This causes the following inconveniences.

(1) Since it is difficult to actively move the molten metal in the latter half of melting, it is impossible to immerse the remaining mass at this point and promote low-temperature melting. - (2) Since the molten metal is at rest or in a state close to this,
During refining, a refining lance is immersed in a vortex and refining can only be done by bubbling, which makes the work complicated and requires long refining work and a large amount of refining agent to obtain the full refining effect.

(3) Furthermore, when removing molten slag floating on the surface of the molten metal, due to the floating slag being spread throughout the furnace, The work of discharging slag from the furnace using the on-board slag removal jig or dedicated slag removal (including stirring) machine is extremely complicated and difficult, and is extremely inefficient and takes a long time. I need it.

[Purpose of the invention]

The present invention has been made in consideration of the above conventional problems, and has a configuration in which the molten metal can be actively moved, the direction of movement thereof is variable, and the starting point position and direction of movement can be appropriately selected. The object of the present invention is to provide an in-furnace molten metal stirring device that can reduce metal loss and save energy by promoting the melting of residual lumps in the furnace, and can facilitate and rationalize refining and slag removal.

[Structure of the invention]

The in-furnace molten metal stirring device of the present invention is an electromagnetic molten metal stirring device installed under the hearth, and the inductor provided in the electromagnetic molten metal stirring device can freely change the direction of magnetic field movement and improve the molten metal movement ability. and is arranged so that it can be moved horizontally, rotated, and moved up and down freely, so that the starting point and direction of movement of the molten metal in the furnace can be appropriately selected according to the stage of each melting process. It is characterized by:

〔Example〕

An embodiment of the present invention will be described below based on FIGS. 1 to 3.

FIG. 1 shows an overview of the in-furnace molten metal agitation device of this embodiment, and also shows the situation in the furnace in the second half of the period when the molten metal has subsided. The lower part of the aluminum melting furnace body is formed by a side furnace wall 1 having a cylindrical shape and a bottom hearth 2 having a dish shape. The melting furnace main body is configured to be tiltable by a tilting cylinder 6 whose working end is connected from below to the opposing edge of the hearth 2 facing that position.

At the lower end of the side furnace wall 1, a slag removal port 3 for removing molten slag inside the furnace and a tapping port 4 for taking out molten metal are provided. Molten metal 8 is stored at the bottom of the furnace, and on the surface of the molten metal 8, residual lumps 9 are exposed before the melt falls off, and slag 10 is floating, as if in the latter half of melting.

An electromagnetic molten metal stirring device 7 is installed below the aluminum melting furnace main body so as to be in a non-contact state with the lower surface of the bottom hearth 2. The upper surface of this electromagnetic molten metal stirring device 7 has a concave shape so that it can face the hearth 2 closely at a certain distance. An inductor (magnetic field generating device) 7a is provided. The electromagnetic molten metal stirring device 7 moves up and down, rotates, and moves on the running rail 1 with respect to the hearth 2 of the melting furnace.
2 can be moved freely horizontally, and the inductor 7a can be set at any position below the hearth 2. The inductor 7a is capable of changing the moving direction of the magnetic field and generates a moving magnetic field, and is also capable of forward and reverse movement, and uses the moving magnetic field to move the molten metal 8 in the furnace in variable forward and reverse directions. have the ability to obtain

In the above configuration, the operating procedure of the inner bay hot water stirring device according to the present invention will be explained in the order of each step as follows.

[1] Step of promoting dissolution of the remaining lumps 9 in the furnace During the latter half of the melting of the raw materials in the furnace, the remaining lumps 9, which have not yet melted, are floating on the surface of the molten metal 8 in the furnace, as described above. In order to promote the melting of this residual mass 9, the electromagnetic molten metal stirring device 7 is moved horizontally on the running rail 12, and the inductor 7a is installed close to the furnace wall 1 side as shown at position D in FIG. , reverse the direction of movement of the magnetic field.

[2] Process of immersing and melting the remaining lump 9 in the furnace with molten metal Next, move the electromagnetic molten metal stirring device 7 so that the center of the inductor 7a matches the center of the hearth 2, and move the electromagnetic molten metal stirring device 7 to position B in FIG. As shown at position A or position C, the inductor 7a is connected to the center of the furnace and the slag removal port 3.
(Position B), or any direction that makes 45 degrees to the left and right to this direction (Position A or C)
, and repeat the forward and reverse movement of the magnetic field several times using the inductor 7a.

[3] Automatic refining process When the molten metal 8 in the furnace reaches a predetermined temperature through the above-described immersion melting process, the automatic refining process is carried out as follows.

The electromagnetic molten metal stirring device 7 rotates at the center of the hearth 2, the inductor 7a is set at the C position shown in FIG. 2, and the forward and reverse movement of the magnetic field is repeated several times. Along with the forward and reverse movement of the magnetic field, the refining lances 11 and 11 are charged into the molten metal 8 in the furnace,
Automatically supplies refining agent into the furnace. The refining lance 11 is arranged so that its tip is located near one end of the inductor 7a.

[4] Slag removal process After the above automatic refining process, the electromagnetic molten metal stirring device 7 is rotated, and its inductor 7a removes the slag 10 floating and scattered on the surface of the molten metal 8 in the furnace near the slag removal port 3. Either the molten slag 10 is set at a position where the slag 10 can be collected near the center of the furnace, that is, position B shown in FIG. , reverse the direction of movement of the magnetic field.

The setting of the inductor 7a performed in each of the above steps can be changed by presetting by pattern or by remote control (one-touch).
The location and operation can be confirmed on surveillance television.

Next, 5, the state of the molten metal 8 and molten slag lO in the furnace in each of the above steps will be explained based on FIG.

[1] Process of promoting melting of the remaining ingot 9 , 8), and it is difficult to absorb radiant energy such as fire damage. Furthermore, in the latter half of the melting period when the molten metal 8 and the residual mass 9 coexist, the surface of the residual mass 9 in the furnace is heated to a high temperature and oxidation is promoted, making the melting even more difficult. In the dissolution promotion step in this example,
As shown in the third diagram, the molten metal 8 around the remaining lump 9 is moved in a swirling manner or collides with the furnace wall 1, so that
The outer periphery of the remaining lump 9 is scraped off by the erosive action of the molten metal 8, thereby preventing the surface of the remaining lump 9 from being oxidized. Further, due to the swirling or collision movement of the molten metal 8 in the furnace, a wave-forming phenomenon occurs on the surface of the molten metal 8, and this wave-forming phenomenon lowers the surface temperature of the molten metal compared to when the molten metal 8 is in a stationary state (general In this example, the temperature is 76°C, whereas in a static state it is 800°C or higher.
5° C. or lower), and the average heat transfer area can be made larger than in a static state. This decrease in surface temperature and increase in heat transfer area is expressed by the general formula for heat transfer: Q=U−A·ΔT−H. Here, Q: amount of heat transferred by metal (Kcal), U: average heat transfer coefficient (Kc
al/rd・h−”C), A: Average heat transfer area (resistance) of the object to be heated, ΔT: Average temperature difference between the atmosphere and the object to be heated ('C), H: Melting time (h) In the above general formula for heat transfer, in this example, A and ΔT become large, so the amount of heat transferred to the object to be heated during metal melting increases.Erosion effect by the molten metal 8 and the molten metal surface Due to the wave-forming phenomenon, the melting of the lump 9 remaining in the furnace is significantly accelerated compared to when the molten metal is in a stationary state.

[2] Immersion melting process of the in-furnace residual lump 9 with molten metal In this step, the in-furnace molten metal 8 is immersed in the position A-B or C shown in FIG. 3, respectively, of the inductor 7a shown in FIG. , - Residue mass 9 floating near the center of the furnace, flowing to a B+ or C8 state
collide with As a result, the remaining lump 9 is completely collapsed (so-called crumbling), and it becomes possible to melt it by immersion in the molten metal.

[3] Automatic refining process In this process, the molten metal 8 in the furnace is actively moved in a variable manner as shown in C2 in FIG. Compared to the case where the refining agent is added, the refining agent can be effectively stirred simply by automatically supplying the refining agent.

[4] In this step of the slag removal process, the inductor 7a shown in FIG.
Depending on the position setting, the molten metal 8 in the furnace will flow in the state shown in FIG. The slag is collected in one place at the optimum position.

〔Effect of the invention〕

As described above, the in-furnace molten metal stirring device of the present invention installs the inductor at the most appropriate position under the hearth according to each process in the latter half of raw material melting, so as to obtain an effective flow state of the molten metal. Because of this structure, the following effects can be achieved significantly.

[1] By actively variable movement of the molten metal during the latter half of metal melting to promote immersion of residual lumps and low-temperature melting, energy savings (3% or more reduction compared to conventional methods) and reduction of metal loss due to oxidation suppression (conventional (10% or more reduction compared to the example)
became possible.

[2] Facilitation of automatic refining through active movement of molten metal during refining has made it possible to shorten refining time, save labor, and improve productivity. In a 60T/CH Al melting furnace, the conventional 2 lances/furnace lance required 20 minutes/CH, but with unmanned operation (preset unmanned or remote control)
Complete refining was possible within 0 minutes/CH. In addition, by improving the efficiency of stirring the refining agent, the amount of refining agent used has been reduced to 173% compared to the conventional one.
was able to save on.

[3] By concentrating the slag in one place through active variable movement of the slag in the furnace during slag removal, the slag removal time can be shortened.
It has become possible to save labor and improve productivity. Said 60T/C
In the H Al melting furnace or holding furnace, conventionally it took 40 minutes/CH by 3 people from 3 places/from the slag removal L1 of the furnace, but in the present invention it took 20 minutes/CH from 1 place/from the closing part of the furnace. min lC
It became possible to remove slag within H.

[4] In the above 60T/CH Al melting furnace, it became possible to achieve homogenization of the molten metal within 5 minutes.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a schematic configuration diagram of main parts showing an embodiment of the present invention;
Figure 2 is an explanatory diagram showing the setting position of the inductor, and Figure 3 is an explanatory diagram showing the setting position of the inductor.
It is an explanatory view showing the flow situation of the molten metal in the furnace corresponding to the figure. 1 is a furnace wall, 2 is a hearth, 7 is an electromagnetic molten metal stirring device, and 7a is an inductor (moving magnetic field generator).

Claims (1)

[Claims] 1. An electromagnetic molten metal stirring device installed under the hearth, in which the inductor installed in the electromagnetic molten metal stirring device has the ability to freely change the direction of magnetic field movement and move the molten metal, and is capable of horizontal movement and rotation. An in-furnace molten metal stirring device characterized in that it is provided so that it can freely move and move up and down.