WO2018026066A1

WO2018026066A1 - Molten metal treatment apparatus and treatment method

Info

Publication number: WO2018026066A1
Application number: PCT/KR2016/014021
Authority: WO
Inventors: 하창수
Original assignee: 주식회사 포스코
Priority date: 2016-08-04
Filing date: 2016-12-01
Publication date: 2018-02-08

Abstract

The present invention comprises: a container having a space formed therein for accommodating molten metal; an agitator installed over the container so as to be movable upward and downward; a treatment agent feeder installed over the container so as to feed a treatment agent for treating the molten metal; and an injector enabling gas injection to at least a partial region of the molten metal so that at least the partial region of the molten metal has a molten surface height different from the molten surface height of other regions thereof. The molten metal can be easily mixed with the treatment agent.

Description

Molten metal processing device and processing method

The present invention relates to a molten metal processing apparatus and a processing method thereof, and more particularly, to a molten metal processing apparatus and a processing method capable of easily mixing the molten metal and the processing agent.

The steelmaking industry consists of preliminary treatment of the molten iron from the blast furnace and charging it into the converter, followed by the converter refining and the secondary refining process to manufacture the cast through a continuous casting process. When sulfur (S) is present in a large amount in steel, it may adversely affect steel properties such as causing cracks, lowering brittleness, and causing red shortness.

The molten iron preliminary treatment is a process performed before supplying the molten iron from the blast furnace to the converter. In the molten iron pretreatment, a dephosphorization process for removing phosphorus from carbon (C), silicon (Si), manganese (Mn), phosphorus (P), and sulfur (S), which are five impurities included in the molten iron, and a desulfurization process for removing sulfur This can be done mainly. At this time, the desulfurization process may be performed in a state in which molten iron is contained in the ladle which is a transport container. For example, the desulfurizing agent may be introduced into the molten iron in the ladle, and the stirrer may be immersed in the molten iron to rotate. Thus, sulfur contained in the molten iron may be removed while reacting with the sulfur desulfurization agent.

Conventionally, in order to improve the reactivity of sulfur and the desulfurizing agent, a structure was installed on the sidewall or the bottom of the ladle to adjust the flow of molten iron. That is, the molten iron rotated by the stirrer hit the structure and moved downward, or induced an asymmetric flow on the molten iron surface, thereby promoting the introduction of the desulfurization agent into the molten iron. However, the structure collides with the molten iron and can be easily broken, there is a problem that the productivity of the ladle is reduced to reduce the volume.

(Patent Document 1) JP1976-112416 A

(Patent Document 2) JP5691207 B

The present invention provides a molten metal processing apparatus and a method for treating the same, which can generate an asymmetrical vortex in the molten metal being stirred.

The present invention provides a molten metal processing apparatus and a processing method thereof that can easily mix the molten metal and the treatment agent.

The present invention provides a container for forming a space accommodated in the molten metal therein; A stirrer movably installed in a vertical direction to an upper portion of the vessel to agitate molten metal contained in the vessel; A treatment agent feeder installed on an upper portion of the vessel to supply a treatment agent for treating molten metal; And an injector located at an upper portion of the container, capable of injecting gas into at least a portion of the molten metal so that the height of the at least one region of the molten metal is different from the height of the surface of the other region. Include.

The injector, a lance for injecting gas in the downward direction; And a gas supply unit connected to the lance to supply gas to the lance. Include.

The lance is disposed between one-fifth and four-fifths between the periphery at the center of the vessel.

The lance injects gas toward the rotation direction of the stirrer.

The plurality of lances are provided, a plurality of lances are arranged only on one side of the stirrer.

The gas includes an inert gas, and the gas supply unit forms a first storage unit for storing the inert gas and a path through which the gas moves, one end of which is connected to the lance and the other end of which is connected to the first storage unit. A heating unit installed in at least one of the first storage unit and the supply line to heat a supply line and a gas; Include.

The gas supply unit further includes a second storage unit storing a reducing gas, wherein the supply line includes: a first pipe connected to the first storage unit, a second pipe connected to the second storage unit, and one end And a third pipe connected to the lance and the other end connected to the first pipe and the second pipe.

The present invention relates to a method for treating molten metal contained in a container, the stirring of the molten metal with a stirrer, the treatment agent is introduced into the molten metal, and the molten metal is melted so that the hot water level of at least a portion of the molten metal is different from the hot water level of another region. Injecting gas into at least a portion of the metal.

The process of injecting the gas may include forming a downflow on the molten metal, and at least a portion of the region where the gas and the molten metal are in contact with each other and the region into which the molten metal treatment agent is injected are overlapped.

The spraying of the gas may include spraying an inert gas in a direction in which the molten metal is stirred.

The supplying of the gas includes heating and spraying the gas.

Injecting the gas includes mixing the inert gas with the reducing gas and then injecting the gas.

The energy density delivered by the gas to the surface of the molten metal in the process of injecting the gas is 0.2W / ton or more.

The container includes a ladle for receiving the molten iron and the treatment agent includes a desulfurizing agent.

According to embodiments of the present invention, by supplying an inert gas to one side of the molten metal is stirred, it is possible to form different heights of one side and the other side of the molten metal. Thus, when the molten metal is stirred while supplying an inert gas, an asymmetrical vortex may occur in the molten metal. Therefore, the treatment agent introduced into the molten metal and the molten metal can be quickly and easily mixed to promote the reaction.

For example, in the case of performing a desulfurization process in which a desulfurizing agent is added to the molten iron, an asymmetrical vortex may be generated in the molten iron to promote the reaction of the molten iron and the desulfurizing agent. Therefore, it is possible to shorten the time of the desulfurization process to improve the efficiency of the process. In addition, since it is possible to generate an asymmetrical vortex without installing a separate structure inside the ladle, it is possible to prevent the problem that the volume of the ladle decreases productivity is reduced. In addition, since the structure is not installed, maintenance work due to the breakage of the structure may not be performed, and thus maintenance of the facility may be facilitated.

1 is a view showing the structure of a molten metal processing apparatus according to an embodiment of the present invention.

2 is a view showing the position of the lance according to an embodiment of the present invention.

3 is a view showing an injector according to another embodiment of the present invention.

4 is a view showing an injector according to another embodiment of the present invention.

5 is a view showing a gas supply unit according to another embodiment of the present invention.

6 is a view showing the operation of the molten metal processing apparatus according to an embodiment of the present invention.

Figure 7 is a graph showing the desulfurization behavior over time of Examples and Comparative Examples of the present invention.

Figure 8 is a graph comparing the desulfurization rate constant of the present invention and the comparative example according to the flow rate of the gas.

9 is a graph comparing the CaO utilization efficiency of the Examples and Comparative Examples of the present invention.

10 is a graph showing the relationship between the stirring energy density per ton of molten iron and the CaO utilization efficiency of the inert gas according to an embodiment of the present invention.

Hereinafter, with reference to the accompanying drawings will be described an embodiment of the present invention in more detail. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various forms, and only the embodiments are intended to complete the disclosure of the present invention and to those skilled in the art to fully understand the scope of the invention. It is provided to inform you. BRIEF DESCRIPTION OF THE DRAWINGS The drawings may be exaggerated in order to illustrate the invention in detail, in which like reference numerals refer to like elements.

1, the molten metal processing apparatus 1000 according to an embodiment of the present invention, the container 100 to form a space accommodated in the molten metal therein, the molten metal accommodated in the interior of the container 100 Stirrer 200 is installed to be movable in the vertical direction to the top of the vessel 100 to agitate, a treatment agent supply (not shown) installed on the top of the vessel 100 to supply a treatment agent for processing molten metal, and molten metal It is possible to inject a gas to at least a portion of the molten metal so that the height of the water surface of at least a portion of the surface is different from the height of the surface of the other area, and includes an injector 400 located on the top of the container (100).

At this time, the molten metal may be molten iron, the container 100 may be a ladle to accommodate the molten iron therein, the treatment agent may be a desulfurization agent. Therefore, the molten metal processing apparatus 1000 may perform a process of removing sulfur in the molten iron.

The container 100 is formed in a cylindrical shape and has an inner space, and an upper portion thereof can be opened. The outer shape of the container 100 may be formed of a shell, and a plurality of refractory layers may be provided inside the shell. The container 100 may accommodate molten metal and the like manufactured in a melting furnace such as a blast furnace or an electric furnace therein. However, the shape and structure of the container 100 may vary without being limited thereto.

The stirrer 200 serves to mix the molten metal and the treating agent by stirring the molten metal inside the vessel 100. The vertical center axis of the stirrer 200 may be disposed on the same line as the vertical center axis of the vessel 100 or may be disposed at a position similar to the vertical axis. Therefore, the stirrer 200 may agitate the molten metal at the center of the vessel 100 to stir the molten metal as a whole. The stirrer 200 may include a rotating shaft 210 installed on the upper portion of the vessel 100, and a plurality of blades 220 connected to the rotating shaft 210.

The rotating shaft 210 may extend in the vertical direction. The rotation shaft 210 may be connected to the rotation driver 230 to rotate in one direction. Accordingly, when the rotating shaft is rotated while the blades 220 are immersed in the molten metal, the molten metal may be stirred while the blades 220 rotate. In addition, the rotation shaft 210 may be connected to a vertical driver (not shown) to move in the vertical direction. Thus, by moving the rotary shaft 210 up and down, the blade 220 connected to the rotary shaft 210 can be immersed in the molten metal or moved to the upper side of the molten metal.

The blade 220 may extend in a direction crossing the extending direction of the rotation shaft 210. The blade 220 may be provided in plural and may be radially connected to the lower end of the rotation shaft 210. The blade 220 may be immersed in the molten metal to be in direct contact with the molten metal, and rotate to stir the molten metal. Thus, a vortex (Vortex) is formed in the molten metal can be easily mixed with the molten metal and the treatment agent. However, the structure and shape of the blade 220 is not limited thereto and may vary.

Treatment agent feeder (not shown) serves to supply the treatment agent to the molten metal. The treatment agent feeder is installed above the vessel 100. The treating agent supplier may supply the treating agent between the central portion and the inner wall of the container 100. Since the stirrer 200 is positioned at the center of the vessel 100, the treatment agent supply may not be located at the center of the vessel 100. In addition, when the treatment agent supplier supplies the treatment agent to the inner wall of the container 100, it may be difficult to mix the treatment agent with the entire molten metal.

Accordingly, in consideration of the location of the stirrer 200 and the fact that the treatment agent is easily mixed with the entire molten metal, the treatment agent supply may be disposed between the central portion and the wall of the container 100 to supply the treatment agent. For example, the treatment agent feeder may be located at about a half point between the central portion of the vessel 100 and the wall in the transverse direction. However, the location of the treatment agent feeder may vary but is not limited thereto.

At this time, the treatment agent supply device may be provided with a chute that can form a moving path of the treatment agent and the length can be adjusted. Therefore, when supplying a treating agent, the length of the chute can be increased so that the outlet of the chute can be brought close to the center of the container 100 in a range that does not disturb the shanghai of the stirrer 200. Conversely, the length of the chute can be reduced once the treatment agent supply is complete. Thus, the treatment agent is wound into the center of the vortex generated in the molten metal by the stirrer 200, and the treatment agent can be rapidly mixed with the molten metal to react.

In the case of performing the desulfurization process of the molten iron, the treating agent may contain quicklime (CaO). In addition, a fluorite, an aluminum material (Al-ash), etc. may be mixed as a solvent. However, the structure of the treatment agent feeder and the components contained in the treatment agent may vary but are not limited thereto.

2 is a view showing the position of the lance according to an embodiment of the present invention, Figure 3 is a view showing an injector according to another embodiment of the present invention, Figure 4 is a view showing an injector according to another embodiment of the present invention Drawing.

Referring to FIGS. 1 and 2, the injector 400 supplies gas to a portion of the molten metal to change the height of the hot water surface of the portion of the molten metal from other regions. Thus, when generating the vortex in the molten metal with the stirrer 200, when the injector 400 injects gas, one side and the other side may not be symmetrical with respect to the center of the molten metal. Thus, an asymmetrical vortex is formed in the molten metal so that the downflow develops on the surface of the molten metal, and the amount of the treatment agent wound on the molten metal can be increased. The injector 400 includes a lance 410 for injecting gas in a downward direction, and a gas supply unit 420 connected to the lance 410 to supply gas to the lance 410.

The lance 410 serves to inject gas into a portion of the molten metal. For example, the lance 410 may be disposed on the right side of the stirrer 200 and may inject gas into the upper portion of the right side of the molten metal. Thus, the right region of the molten metal is pressed downward by the gas, the height of the right region is lowered, the height of the left region can be increased. However, the location where the lance 410 is disposed and the area in which the gas is injected may be various.

When the lance 410 injects an inert gas to only a portion of the molten metal in the container 100, waves are generated in the molten metal. Accordingly, the downflow occurs on the surface of the molten metal, and the downflow can be suppressed or prevented from rising to the surface of the molten metal. Therefore, while the treatment agent stays in the molten metal continuously, the reaction time with the molten metal increases, and the desulfurization efficiency may be improved.

In addition, the lance 410 may be located above the container 100. The lance 410 may extend in the vertical direction, and may form a path through which the gas moves. One lance 410 may be provided, and a lower end of the lance 410 may be provided with an injection hole for injecting gas. Thus, the gas supplied into the lance 410 may be injected downward through the injection hole.

In addition, the lance 410 may be disposed between one-fifth and four-fifths between the periphery at the center of the vessel 100 in the transverse direction. In this case, the stirrer 200 may be positioned at the center of the vessel 100, and an inner wall of the vessel 100 may be positioned at an outer portion of the vessel 100. That is, the lance 410 may inject gas between the stirrer 200 and the inner wall of the vessel 100.

If the lance 410 is located 1/5 of the point between the center and the outer portion of the vessel 100, the lance 410 may be far from the treatment agent supply and may be close to the stirrer 200. . As a result, the gas injected from the lance 410 may not press down the region supplied with the molten metal treatment agent. Thus, the treating agent may easily float to the surface of the molten metal, and the treating agent may not be easily wound into the molten metal.

If the lance 410 is positioned after 4/5 between the center and the periphery of the vessel 100, the lance 410 is far from the treatment agent supply and is close to the inner wall of the vessel 100. Can lose. As a result, the gas injected from the lance 410 may not press down the region supplied with the molten metal treatment agent. Thus, the treating agent may easily float to the surface of the molten metal, and the treating agent may not be easily wound into the molten metal.

The lance 410 is one-fifth between the periphery of the center of the vessel 100 so that at least a portion of the region where the gas injected from the lance 410 contacts with the molten metal and the region where the molten metal is supplied are superimposed. Can be placed between 4/5 points. That is, the lance 410 may be disposed closer to the treatment agent supply than to the stirrer 200 or the wall of the vessel 100. Thus, the gas injected from the lance 410 can easily suppress or prevent the injury of the treatment agent. That is, the lance 410 may be disposed to be close to the treatment agent supply.

In this case, as illustrated in FIG. 3, the inclination of the lance 410 may be adjusted to allow the gas to be injected toward the rotation direction of the stirrer 200. Thus, the gas injected from the lance 410 does not interfere with the stirring operation of the stirrer 200, rather it may induce a flow of molten metal so that the stirring is well. Thus, the gas injected from the lance 410 provides the stirring force so that the molten metal can be stirred more easily. However, the method of directing the gas in the direction of rotation of the stirrer may be various.

Meanwhile, as shown in FIG. 4, a plurality of lances 410 may be provided. When the number of lances 410 is increased, the number of areas in which the gas injected from the lances 410 and the molten metal contact or the area of the areas in contact with each other may increase. For example, a first lance 410, a second lance 410, and a third lance 410 may be provided in an outward direction from the center of the container 100. As a result, the height difference between the region pressed downward by the gas and the region not pressed down may increase, and downward flow may be more actively generated so that the treating agent may be more rapidly charged into the molten metal.

The plurality of lances 410 may be disposed only on one side of the stirrer 200. For example, the plurality of lances 410 may be disposed only on the right side of the stirrer 200. Therefore, when gas is injected into the lance 410, a height difference may occur between the left region and the right region of the molten metal.

Or, it may be disposed only in any one of the two areas divided by the stirrer 200 of the molten metal in the transverse direction. For example, the molten metal may be divided into a left region and a right region based on the stirrer 200, and the lances 410 may be disposed only in the right region or the left region. Therefore, the gas is supplied only to the left side or the right side of the molten metal, so that a height difference may occur between the left side and the right side. As a result, an asymmetric flow may be induced on the hot water surface to increase the amount of the treatment agent wound into the molten metal. However, the number and location of the lance 410 is provided is not limited to this may vary.

The gas supply unit 420 serves to supply gas to the lance 410. In this case, the gas may be an inert gas. The gas supply unit 420 may include a first storage unit 421 storing an inert gas and a path through which the gas moves, one end of which is connected to the lance 410 and the other end of which is connected to the first storage unit 421. A supply line 423 and a heating unit (not shown) installed in at least one of the first storage unit 421 and the supply line 423 to heat the gas.

The first storage unit 421 may be a tank for storing an inert gas therein. For example, the inert gas may include at least one of nitrogen and argon gas. However, the present invention is not limited thereto, and various inert gases that do not oxidize the molten metal may be used. That is, since the gas which oxidizes molten iron is disadvantageous to desulfurization and can generate dust, an inert gas which does not oxidize molten iron can be used.

The supply line 423 may form a path through which gas moves, one end may be connected to the lance 410, and the other end may be connected to the first storage unit 421. Thus, the inert gas stored in the first storage unit 421 may be delivered to the lance 410 through the supply line 423. Supply line 423 may be provided with a flow meter for measuring the flow rate of the gas, and a valve for opening and closing the movement path of the gas formed by the supply line 423. However, the structure of the supply line 423 may be various but not limited thereto.

The heating unit (not shown) serves to heat the gas supplied to the lance 410. For example, the heating unit may be a hot wire, and may be disposed to surround a circumference of at least one of the first storage unit 421 and the supply line 423. Accordingly, the heating unit may increase the temperature of the gas supplied to the lance 410 by heating at least one of a space in which the gas is stored and a path through which the gas moves. Therefore, it is possible to suppress or prevent the molten metal from being cooled by the gas injected through the lance 410. However, the method of heating the gas by the heating unit is not limited thereto and may vary.

Meanwhile, as illustrated in FIG. 5, the gas supply unit 420 may further include a second storage unit 422 for storing the reducing gas.

The second storage unit 422 may be a tank for storing a reducing gas therein. The reducing gas may be a hydrocarbon gas. For example, methane may be used as the hydrocarbon gas. Methane can increase the desulfurization rate. However, the present invention is not limited thereto, and various reducing gases may be used.

At this time, the supply line 423 serves to deliver the gas of the first storage unit 421 and the second storage unit 422 to the lance 410. The supply line 423 includes a first pipe 423a connected to the first storage unit, a second pipe 423b connected to the second storage unit 422, and one end connected to the lance 410, and the other end thereof. The third pipe 423c may be connected to the first pipe 423a and the second pipe 423b.

One end of the first pipe 423a is connected to the first storage unit 421 and forms a path through which gas moves. The first pipe 423a may be provided with a first control valve 423d for opening and closing a gas movement path or adjusting a flow rate. Accordingly, the operation of the first control valve 423d may be controlled to select a time point at which the inert gas is supplied to the lance 410 or the supply is stopped, and the amount of the inert gas supplied to the lance 410 may be adjusted.

In addition, the first pipe 423a may be provided with a first flow meter (not shown) for measuring the flow rate of the gas inside the first pipe 423a and a first pressure gauge (not shown) for measuring the pressure. Therefore, the amount of inert gas supplied to the lance 410 can be confirmed, and the inert gas of the desired amount or desired pressure can be accurately supplied to the lance 410.

One end of the second pipe 423b is connected to the second storage unit 422 and forms a path through which gas moves. The second pipe 423b may be provided with a second control valve 423e for opening and closing the gas movement path or adjusting the flow rate. Accordingly, the operation of the second control valve 423e may be controlled to select a time point at which the reducing gas is supplied to the lance 410 or the supply is stopped, and the amount of the reducing gas supplied to the lance 410 may be adjusted. When the second control valve () blocks the movement path of the gas, it is possible to block the heat of the molten metal or the flame from flowing into the second storage unit 422. Therefore, it is possible to prevent backfire and explosion of the reducing gas of the second storage unit 422.

In addition, a second flow meter (not shown) for measuring the flow rate of the gas inside the second pipe 423b and a pressure gauge (not shown) for measuring the pressure may be installed in the second pipe 423b. Therefore, the amount of reducing gas supplied to the lance 410 can be confirmed, and the reducing gas of the desired amount or the desired pressure can be accurately supplied to the lance 410.

One end of the third pipe 423c is connected to the lance 410, and the other end is connected to the other end of the first pipe 423a and the other end of the second pipe 423b. That is, the inert gas that moves the first pipe 423a and the reducing gas that moves the second pipe 423b may meet and mix in the third pipe 423c and then be supplied to the lance 410. The third pipe 423c may include: a mixing member forming a space in which an inert gas and a reducing gas are mixed therein; and a path member forming a path through which the gas moves to deliver the gas mixed in the mixing member to the lance 410. It may include.

The mixing member may be formed in a box shape having an inner space. The other end of the first pipe 423a and the other end of the second pipe 423b may be connected to the mixing member. Thus, the inert gas and the reducing gas may meet and mix inside the mixing member.

The path member forms a path through which the gas moves, one end of which is connected to the lance 410, and the other end of which is connected to the mixing member. Thus, the gas mixed inside the mixing member may be supplied to the lance 410 through the path member. In addition, the path member may be made of a flexible material. Thus, the path member can be at least partially refracted and can suppress or prevent the movement of the lance 410 from being disturbed by the path member.

For example, the lance 410 may be installed and supported by the up and down driver of the stirrer 200, and may move up and down by the up and down driver. Thus, the path member connected to the lance 410 can be made of a flexible material so that the lance 410 can be easily moved up and down. However, the structure of the third pipe 423c may not be limited thereto and may vary.

In this case, the heating unit may be installed in the second storage unit 422. Thus, the heating unit can heat both the inert gas and the reducing gas supplied to the lance 410. Thus, cooling of the molten metal due to the gas injected from the lance 410 can be suppressed or prevented. However, the location where the heating unit is installed may be various but not limited thereto.

The inert gas may be supplied only to a portion of the molten metal that is stirred in this way to form different heights of the surface of the molten metal and a surface of the other of the molten metal. Thus, when the molten metal is stirred while supplying an inert gas, an asymmetrical vortex may occur in the molten metal. Therefore, the treatment agent introduced into the molten metal and the molten metal can be quickly and easily mixed to promote the reaction.

Referring to FIG. 6, a molten metal treating method according to an exemplary embodiment of the present invention is a method of treating molten metal contained in a container, agitating the molten metal with a stirrer, injecting a treating agent into the molten metal, and applying at least the molten metal. Injecting a gas into at least a portion of the molten metal so that the height of the water surface in some areas is different from the height of the water surface in other areas. At this time, the order of the operation of stirring the molten metal, the operation of injecting the treatment agent into the molten metal, and the operation of spraying the gas to at least a portion of the molten metal may be variously selected.

At this time, the molten metal may be molten iron, the container 100 may be a ladle to accommodate the molten iron therein, the treatment agent may be a desulfurization agent. Therefore, the molten metal treatment method may be a method of removing sulfur in the molten iron.

The container 100 loaded with molten metal is seated on a support (not shown). The stirrer 200 is moved downward to immerse the blade 220 in the molten metal. At this time, the stirrer 200 is disposed in the center of the vessel 100, the upper surface of the blade 220 may be moved to a position lower than the molten metal of the molten metal to agitate the molten metal.

Then, the stirrer 200 is operated to stir the molten metal. Vortex flow may occur in the molten metal by the rotation of the blade 220. Therefore, the height of the center portion of the molten metal can be decreased, and the height of the outer portion can be increased. At this time, the treatment agent may be added to the molten metal.

In addition, the gas may be injected into a portion of the molten metal (eg, upper right) through the lance 410. When the lance 410 injects gas only to a portion of the molten metal in the container 100, an asymmetrical vortex occurs, causing waves to rise and fall on the molten metal's hot water surface. The height h2 of some regions (eg, upper right) of the molten metal may be lowered by the inert gas, and the height h1 of other regions (eg, upper left) may be higher. Accordingly, the downflow occurs on the surface of the molten metal, and the downflow can be suppressed or prevented from rising to the surface of the molten metal. Therefore, while the treatment agent stays in the molten metal continuously, the reaction time with the molten metal increases, and the desulfurization efficiency may be improved.

As such, the gas injected from the lance 410 may form a downflow to the molten metal. When at least a portion of the region where the gas and the molten metal are in contact with each other and the region into which the molten metal treatment agent is injected are overlapped, the downflow caused by the gas can more effectively suppress or prevent the injury of the treatment agent.

At this time, the gas may be injected between 1/5 to 4/5 points between the inner wall and the center of the container 100 in the transverse direction. When the gas is supplied before the 1/5 point or after the 4/5 point between the center and the inner wall of the container 100, the area where the gas and the molten metal contact and the area where the treatment agent and the molten metal contact each other do not overlap each other. Or overlapping portions may have a small size. Thus, the treating agent may easily float to the surface of the molten metal, and the treating agent may not be easily wound into the molten metal.

Gas may be supplied between 1/5 to 4/5 of the inner wall at the center of the vessel 100 to increase the overlapping portion of the region where the gas and molten metal are in contact, and the region where the molten metal is supplied with the treatment agent. have. That is, the part which supplies a gas and the part which supplies a processing agent can approach each other. Thus, the gas injected from the lance 410 can easily suppress or prevent the injury of the treatment agent.

In addition, the gas may be injected toward the direction in which the molten metal is stirred. Accordingly, the gas may apply a force downward to a portion of the molten metal without disturbing the stirring of the molten metal by the stirrer 200. Therefore, by providing the stirrer 200 can easily stir the molten steel.

At this time, the gas may be heated and then injected into the molten metal. The low temperature of the gas allows the molten metal to cool when in contact with the molten metal. Therefore, the molten metal can be heated to raise the temperature, and the gas whose temperature is raised can be injected into the molten metal to suppress or prevent cooling of the molten metal. The gas may be an inert gas.

In addition, when the gas is supplied to the molten metal, the reducing gas may be mixed with the inert gas and then injected into the molten metal. Reducible gases can increase the desulfurization rate. Thus, when gas is injected into the molten metal, a reducing gas can be mixed into the gas. The inert gas may include at least one of nitrogen and argon gas, and the reducing gas may include a hydrocarbon gas. However, the type of inert gas and the reducing gas may vary, without being limited thereto.

In addition, the energy density delivered by the gas injected from the lance 410 to the surface of the molten metal may be 0.2W / to 4W / ton. If the energy density of the injected gas is less than 0.2W / ton, the gas may not press the molten metal's hot surface, so the height difference may not occur on the hot water surface.If the energy density of the injected gas exceeds 4W / ton, the molten metal in other areas The height of the too high may overflow to the outside of the container 100. Therefore, the lance 410 must inject gas so that the molten metal can be stably received in the container 100 while generating a height difference between some regions of the molten metal and other regions.

Then, when the process of refining the molten metal is completed, the vessel 100 can be separated from the support, and moved to the place where the subsequent process is performed.

As described above, in the case of performing a desulfurization process in which a desulfurization agent is added to the molten iron, an asymmetrical vortex may be generated in the molten iron to promote the reaction between the molten iron and the desulfurizing agent. Therefore, the productivity of the desulfurization process can be shortened. In addition, since an asymmetrical vortex can be generated without installing a separate structure inside the container, maintenance work due to the breakage of the structure can not be performed, and the volume of the container can be reduced to prevent the problem of reduced productivity. have.

7 is a graph showing the desulfurization behavior according to the time of Examples and Comparative Examples of the present invention, Figure 8 is a graph comparing the desulfurization rate constant of the Examples and Comparative Examples of the present invention according to the flow rate of the gas. Hereinafter, the present invention will be described in more detail through experimental examples.

First, a 200kg class reactor was used as a container for molten metal, and 150kg of electrolytic iron was dissolved. The molten metal was added with a carbonization agent and sulfur to adjust the components so that the molten metal contained 4.5% of carbon (C) and 0.035% of sulfur (S). Experimental temperature of the molten metal was about 1350 ℃. Since the experimental furnace was small, the rotation speed of the stirrer was set to 500 rpm to secure the mixing strength similar to that of the large furnace. The lance was positioned at the half point between the stirrer and the wall of the furnace so that an inert gas was injected at the midpoint of the wall of the stirrer and the furnace. In this case, the lance may be a SUS pipe having an internal diameter of 4.57 mm. In order to prevent the lance from clogging due to scattering of the molten metal due to the rotation of the stirrer, a lance was installed about 100 mm above the molten metal. These equipments were tested under four conditions.

Comparative Example (or conventional example) is a desulfurization process without spraying the inert gas to the molten metal, Example 1 is a mixture of inert gas nitrogen and reducing gas methane (CH ₄ ) 8 The desulfurization process was performed while spraying at liter / min, and Example 2 was a desulfurization process while spraying nitrogen, which is an inert gas, to the molten metal at 10 liter / min. Desulfurization process was performed while spraying at 15 liters / min. Samples of molten metal were taken while the experiments were carried out according to each condition, and sulfur desulfurization was analyzed over time to compare the desulfurization rates. In general, the desulfurization rate per unit time is expressed by Equation 1 below.

Equation 1: -d [% S] / dt = K _t * ([% S]-[% S] _e )

Where K _t is the apparent rate constant, [% S] is the sulfur concentration of the sample, and [% S] _e is the sulfur concentration at equilibrium)

At this time, since the value of [% S] _e is very small, considering Equation 1 and integrating Equation 1, Equation 2 below appears.

Equation 2: ln ([% S] / [% S] _o ) =-K _t * t

Where K _t is the apparent rate constant, [% S] is the sulfur concentration of the sample, [% S] _o is the initial sulfur concentration, and t is the time

7 is a graph showing desulfurization behavior according to time of Comparative Example, Example 1, Example 2, and Example 3, and the slope of the graph is a desulfurization rate constant. Referring to FIG. 7, the slope of the graph is steeper than that of the comparative example. That is, the embodiments have a faster desulfurization rate than the comparative example. Thus, by supplying an inert gas to one side of the stirred molten metal to generate an asymmetrical vortex, it can be seen that the desulfurization rate is increased.

In addition, the desulfurization rates of Examples 1 and 2 are faster than those of Example 2. Thus, it can be seen that the desulfurization rate is increased by injecting a reducing gas into the inert gas as in Example 1 or by increasing the amount of inert gas injected per hour as in Example 3.

8 is a graph comparing the desulfurization rate constant according to the flow rate of the gas when only inert gas is supplied to the molten metal and when the inert gas and the reducing gas are mixed and supplied to the molten metal. At this time, nitrogen was used as the inert gas, and methane was used as the reducing gas. Referring to FIG. 8, when the flow rate of the supplied gas is small, the inert gas and the reducing gas are mixed and sprayed faster than the inert gas only. However, as the flow rate increases, the difference in the desulfurization rate in the case of supplying only the inert gas and in the case of supplying the inert gas and the reducing gas mixed with the molten metal decreases to almost eliminate the difference.

That is, when gas is injected to one side of the molten metal, the downflow occurs due to the melt surface wave of the molten metal, and the downflow promotes desulfurization by increasing the amount of treatment agent wound into the molten metal and the residence time in the molten metal. Can be. Thus, desulfurization may be promoted by injecting various gases in addition to nitrogen or methane. However, since the gas oxidizing the component of the molten iron is disadvantageous to desulfurization and can generate dust, an inert gas can be used to generate the downflow to the molten metal.

Figure 9 is a graph comparing the CaO utilization efficiency of the Examples and Comparative Examples of the present invention, Figure 10 is a graph showing the relationship between the agitation energy density, and CaO utilization efficiency of the molten iron ton of the inert gas according to an embodiment of the present invention to be. Hereinafter, the present invention will be described in more detail with reference to other experimental examples.

First, a 300 ton ladle was used as a container for the molten metal, and a lance for injecting a stirrer and an inert gas was placed above the ladle loaded with molten metal, molten metal. In consideration of workability, the lance was placed at least 1 m above the molten iron surface of the molten iron. For example, if the distance from the center of the ladle to the outer shell is R, the lance is positioned at about 0.4R. Nitrogen was used as an inert gas, and the raw material which mixed condensed lime, Al-ash, and fluorspar was used as a processing agent. Using this facility, desulfurization was carried out by varying the inner diameter of the lance, the separation distance between the lance and the hot water surface, and the flow rate of the inert gas, and a sample of molten metal was taken under each condition.

At this time, when performing the desulfurization operation in the ladle it is difficult to take a sample of molten metal in the middle. That is, since the sampling device for taking the sample by the stirrer may be damaged, the sample was taken before and after the desulfurization treatment to compare the sulfur concentration.

Then, CaO utilization efficiency was calculated and compared to compare how CaO in the treatment reacted with sulfur in the molten metal. CaO utilization efficiency can be calculated by Equation 3 below.

Equation 3: CaO utilization efficiency (%) = (([% S] _i -[% S] _f ) / W _CaO ) * 10 * (56/32) * 100

Where [% S] _i is the initial sulfur concentration, [% S] _f is the sulfur concentration after desulfurization, and W _CaO is the unit of CaO per ton of molten iron.

If CaO utilization efficiency is high, even if the same amount of CaO is injected into the molten metal, CaO reacts with more sulfur than if CaO utilization efficiency is low. In other words, high CaO utilization efficiency means high reaction efficiency.

On the other hand, since the experiment is carried out by changing the inner diameter of the lance, the separation distance between the lance and the hot water surface of the molten metal, and the flow rate of the inert gas, it is necessary to collectively summarize the effects of the gas supplied from the lance. Therefore, it is possible to use an equation that can compare the effects of the inner diameter of the lance, the separation distance between the lance and the water surface, and the conditions of the flow rate of the inert gas. The stirring energy delivered to the surface of the molten metal by the gas supplied from the lance can be calculated by Equation 4 below.

Equation 4: Ev = ((6.32 * 10 ^-7 * cosθ) / V) * ((Q ³ * M) / (d ³ * h))

Where Ev is the stirring energy (W / m ³ ), θ is the angle of lance, Q is the gas flow rate (Nm ³ / min), M is the gas injection rate, and V is the volume of molten metal (m ³ ) D is the nozzle diameter of the lance (m) and h is the separation distance (m) between the lance and the molten metal)

In general, since molten iron uses more values per ton than the volume value, the energy density per ton of the molten iron can be calculated by dividing the value obtained in Equation 4 by the specific gravity of the molten iron (6.7). Equation 4 shows that the energy density supplied to the molten iron surface increases as the amount of gas injection increases, the smaller the nozzle diameter of the lance, and the smaller the separation distance between the lance and the molten metal.

At this time, if the separation distance between the lance and the molten metal is too short, there is a problem that the splash of the molten iron caused by the rotation of the stirrer is easily attached to the lance. In addition, if the diameter of the nozzle of the lance is too small, it becomes vulnerable to adhesion now. Therefore, the distance between the lance and the molten metal and the diameter of the nozzle of the lance should be selected in consideration of workability and serviceability.

FIG. 9 is a graph comparing CaO utilization efficiency when not supplying inert gas (comparative example) and supplying inert gas (example) according to sulfur concentration of molten iron before desulfurization treatment. Referring to FIG. 9, the higher the concentration of sulfur, the higher the CaO utilization efficiency tends to appear. In addition, when the inert gas is injected into the molten iron (Example), it is confirmed that CaO utilization efficiency is increased by about 1.5 times compared with the case of not injecting the inert gas (Comparative Example). Therefore, it can be seen that when the inert gas is supplied to one side of the inert gas, the desulfurization treatment rate is improved.

10 is a graph showing a relationship between the average CaO utilization efficiency and calculating the agitation energy density per ton of molten inert gas injected according to the condition of the inner diameter of the lance, the separation distance between the lance and the hot water surface, and the flow rate of the inert gas. to be. Referring to FIG. 10, it can be seen that the CaO utilization efficiency also increases as the stirring energy density increases. That is, it can be seen that the stirring energy density and the CaO utilization efficiency are in proportion. Thus, it can be seen that as the injection amount of the inert gas increases, the smaller the nozzle diameter of the lance, the smaller the separation distance between the lance and the molten metal increases.

In addition, even when the inert gas is not injected (or when the stirring energy density is 0), it is lower than when injecting the inert gas having a CaO utilization efficiency which differs depending on the operating conditions. Therefore, in order to exhibit an effect of improving the desulfurization rate, at least one of the injection amount of the gas, the nozzle diameter of the lance, and the separation distance between the lance and the molten metal may be adjusted to supply a stirring energy density of 0.2 W / ton or more. .

As described above, when performing the desulfurization process of injecting a desulfurization agent into the molten iron, supplying an inert gas to one side of the molten iron generates an asymmetrical vortex in the molten iron, thereby promoting reaction of the molten iron and the desulfurization agent. Therefore, the productivity of the desulfurization process can be shortened.

As described above, in the detailed description of the present invention, specific embodiments have been described, but various modifications may be made without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined not only by the claims described below, but also by equivalents thereof.

Claims

A container forming a space accommodated in the molten metal therein;

A stirrer movably installed in a vertical direction to an upper portion of the vessel to agitate molten metal contained in the vessel;

A treatment agent feeder installed on an upper portion of the vessel to supply a treatment agent for treating molten metal; And

An injector located at an upper portion of the vessel, capable of injecting gas into at least a portion of the molten metal so that the height of the at least one region of the molten metal is different from that of the other region; Molten metal processing apparatus comprising.
The method according to claim 1,

The injector,

A lance for injecting gas downward; And

A gas supply unit connected to the lance to supply gas to the lance; Molten metal processing apparatus comprising.
The method according to claim 2,

And the lance is disposed between one fifth and four fifth points between an outer portion and a central portion of the vessel.
The method according to claim 2,

The lance is molten metal processing apparatus for injecting gas toward the rotation direction of the stirrer.
The method according to claim 2,

The lance is provided with a plurality,

The plural lances molten metal processing apparatus is disposed only on one side of the stirrer.
The method according to claim 2,

The gas comprises an inert gas,

The gas supply unit forms a first storage unit for storing an inert gas, a path through which gas moves, a supply line having one end connected to the lance and the other end connected to the first storage unit, and the gas to heat the gas. A heating unit installed in at least one of the first storage unit and the supply line; Molten metal processing apparatus comprising.
The method according to claim 6,

The gas supply unit further includes a second storage unit for storing a reducing gas,

The supply line may include a first pipe connected to the first storage unit, a second pipe connected to the second storage unit, and one end connected to the lance and the other end connected to the first pipe and the second pipe. Molten metal processing apparatus comprising a third pipe to be.
A method of treating molten metal contained in a container,

Stirring the molten metal with a stirrer, injecting a treatment agent into the molten metal, and injecting a gas into at least a portion of the molten metal such that the height of the bottom surface of the at least some region of the molten metal is different from that of the other region; Molten metal treatment method.
The method according to claim 8,

The spraying of the gas may include forming a downflow in the molten metal.

The molten metal processing method which overlaps at least one part of the area | region which a gas and the molten metal surface contact, and the area | region into which the processing agent of molten metal is injected.
The method according to claim 9,

The process of injecting the gas,

Molten metal processing method comprising the step of injecting an inert gas in the direction in which the molten metal is stirred.
The method according to claim 9,

The process of supplying the gas,

A molten metal processing method comprising the step of heating and then spraying a gas.
The method according to claim 9,

The process of injecting the gas,

A molten metal treatment method comprising the step of injecting an inert gas with a reducing gas and then spraying.
The method according to claim 9,

In the process of injecting the gas

The method of processing the molten metal gas energy delivered to the surface of the molten metal is more than 0.2W / ton.
The method according to any one of claims 8 to 13,

Said container comprising a ladle containing molten iron and said treating agent comprises a desulfurizing agent.