A ladle liquid steel secondary oxidation protection device and method

Abstract

The application discloses a ladle liquid secondary oxidation protection device and method, which comprises a refined liquid ladle, wherein the refined liquid ladle is connected with an intermediate ladle, the top of the intermediate ladle is inserted into a ventilation pipeline, the ventilation pipeline is sealed with a ladle cover of the intermediate ladle, the ventilation pipeline is arranged along the center of the ladle cover of the intermediate ladle to the outer circumference, a vacuum chamber is directly connected below the intermediate ladle, a liquid steel ingot mold is arranged in the vacuum chamber, a long liquid pipe is arranged between the liquid steel ingot mold and the intermediate ladle, and the long liquid pipe extends to below the liquid level in the liquid steel ingot mold. The application provides a method for reducing the secondary oxidation of the liquid steel in the ladle by combustion, the oxygen content in the ladle clearance can be reduced by the method, the secondary oxidation is reduced, the oxygen content in the ladle clearance is consumed, the oxygen partial pressure is reduced, and the secondary oxidation of the liquid steel contact surface of the ladle is reduced. The method is simple and easy to implement, and the effect is obvious.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of steel smelting, and particularly relates to a protection device and method for preventing secondary oxidation of molten steel in a ladle. BACKGROUND

[0002] The problem of controlling secondary oxidation of molten steel in a ladle has been an important part of cleanliness control. At present, the ladle capping technology is mainly adopted to reduce heat loss and secondary oxidation. However, after refining is completed, air enters the ladle through the gap between the ladle and the ladle cover during the waiting time and pouring time of the ladle on the casting machine, and contacts the molten steel and refining slag, so that oxidation reaction occurs, the total oxygen content of the molten steel is increased, and especially during the pouring period, about 30-50 minutes, the molten steel in the ladle continuously decreases, the ladle clearance continuously expands, the air outside continuously enters the clearance, and the refining slag and the molten steel are oxidized, resulting in problems such as excessive inclusions.

[0003] In view of the above factors, a protection device and method for preventing secondary oxidation of molten steel in a ladle are specially designed. The method consumes oxygen in the ladle by a chemical method to reduce the oxygen content, so as to realize reduction of secondary oxidation of the refining slag and the molten steel. The method has faster chemical reaction and better effect. SUMMARY

[0004] The purpose of the present application is to provide a protection device and method for preventing secondary oxidation of molten steel in a ladle to solve the problems in the background art.

[0005] The purpose of the present application is achieved by the following technical scheme: a protection device for preventing secondary oxidation of molten steel in a ladle, comprising a refining molten steel ladle, the refining molten steel ladle being connected with an intermediate ladle, a ventilation pipe being inserted into the top of the intermediate ladle, and the ventilation pipe and a ladle cover of the intermediate ladle being sealed.

[0006] The ventilation pipe is arranged along the center of the ladle cover of the intermediate ladle to the outer circumference.

[0007] A vacuum chamber is directly connected below the intermediate ladle, and a molten steel ingot mold is arranged in the vacuum chamber.

[0008] A long liquid pipe is arranged between the molten steel ingot mold and the intermediate ladle.

[0009] Further, the long liquid pipe extends below the liquid level in the molten steel ingot mold.

[0010] Further, the molten steel ingot mold and the upper port of the vacuum chamber are left with 20-30 centimeters.

[0011] Further, at least one group of cold gas passage holes is arranged on the side wall of the vacuum chamber, and the cold gas passage holes are symmetrically arranged upward and downward.

[0012] Further, the ventilation pipe is a combustible gas channel along the inner layer of the ladle cover of the intermediate ladle, and an argon gas channel is arranged along the outer layer of the combustible gas channel.

[0013] Further, a retaining wall is arranged at the position of the combustible gas channel in the intermediate ladle, and the combustible gas channel extends to below the retaining wall.

[0014] Further, a gas resistance layer is arranged on the bottom surface of the retaining wall close to the inner circle of the combustible gas channel, and the gas resistance layer is an inward recessed layer.

[0015] Further, the lowest plane of the argon gas channel extends to one half of the height of the gas resistance layer, the outlet of the argon gas channel is in an arc shape, and the outlets of the argon gas channels are arranged in a clockwise circumferential manner.

[0016] The outlet of the argon gas channel faces the top surface of the gas resistance layer.

[0017] Further, a part of the combustible gas channel in the intermediate ladle is above the liquid surface of the molten steel, and a part of the combustible gas channel is between the liquid surfaces of the molten steel.

[0018] A use method of a secondary oxidation prevention device for a ladle, comprising the following steps.

[0019] The top of the intermediate ladle is inserted into the ventilation pipe, the ventilation pipe and the ladle cover of the intermediate ladle are sealed, combustible gas is blown into the pipe during the standing and casting process, and the oxidation reaction between the combustible gas and the oxygen in the ladle clearance consumes the oxygen in the clearance.

[0020] Meanwhile, a gas resistance layer is arranged on the bottom surface of the retaining wall close to the inner circle of the combustible gas channel, the gas resistance layer is an inward recessed layer, the lowest plane of the argon gas channel extends to one half of the height of the gas resistance layer, the outlet of the argon gas channel is in an arc shape, and the outlets of the argon gas channels are arranged in a clockwise circumferential manner.

[0021] The outlet of the argon gas channel faces the top surface of the gas resistance layer, a small amount of argon gas is blown in through the argon gas channel to form a micro-positive pressure, and the entry of external oxygen is avoided.

[0022] Compared with the prior art, the beneficial effects of the present application are:

[0023] The present application inserts a ventilation pipe on the top of a ladle, and the ventilation pipe and the ladle cover are sealed. During the standing and casting process, combustible gas is blown into the pipe, and the combustible gas and the oxygen in the ladle headspace have an oxidation reaction, consuming the oxygen in the headspace. The chemical reaction is fast, and the oxygen partial pressure is greatly reduced. At the same time, a small amount of argon gas is blown in to form a slight positive pressure to avoid the entry of external oxygen. Regarding the ventilation amount, during the standing, the ladle headspace is small, and the ventilation amount can be reduced to maintain a low oxygen pressure. During the casting process, the molten steel descends, the headspace increases, and a large amount of external air enters, at which time the gas blowing amount should be increased, so that a large amount of oxygen in the headspace is burned and consumed, thereby reducing the secondary oxidation of the molten steel and the refining slag. The present application is simple and easy to operate, and does not cause any impact on the production rhythm. The effect can be characterized by measuring the ladle residue oxidizability or the total oxygen of the molten steel.

[0024] The present application consumes the oxygen in the ladle by a chemical method, reduces the oxygen content, and thereby realizes reducing the secondary oxidation of the refining slag and the molten steel. The method has faster chemical reaction and better effect. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 is the overall schematic diagram of the present application;

[0026] Figure 2 is the schematic diagram of the combustible gas channel and the argon gas channel arrangement of the present application;

[0027] Figure 3 is the schematic diagram of the present application with a retaining wall;

[0028] Figure 4 is the schematic diagram of the present application with a gas resistance layer;

[0029] Figure 5 is the schematic diagram of the argon gas channel of the present application. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

[0031] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connection" and "connection" should be understood in a broad sense, for example, it can be fixed connection, or detachable connection, or integrally connected; it can be directly connected, or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0032] In the description of the present invention, it should be understood that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0033] like Figures 1-5 As shown, a device for preventing secondary oxidation of molten steel in a ladle comprises a refined steel ladle 1, wherein the refined steel ladle 1 is connected to a tundish ladle 2, a ventilation pipe is inserted into the top of the tundish ladle 2, wherein the ventilation pipe and the ladle cover of the tundish ladle 2 are sealed;

[0034] The ventilation pipe is arranged along the center of the cover of the tundish ladle 2 toward the outer circumference;

[0035] The lower side of the tundish 2 is directly connected to the vacuum chamber 3, and the vacuum chamber 3 is provided with a molten steel ingot mold 4;

[0036] A long liquid pipe 5 is provided between the molten steel ingot mold 4 and the tundish 2 .

[0037] In order to facilitate use, the long liquid tube 5 is inserted below the liquid level of the molten steel, which avoids secondary oxidation of the cast steel liquid and the introduction of non-metallic inclusions caused by the use of refractory water nozzles, thereby improving the purity of the molten steel. The long liquid tube 5 extends below the liquid level in the molten steel ingot mold 4.

[0038] In order to facilitate forming a vacuum environment during use and reduce the introduction of impurities, a gap of 20-30 centimeters is left between the molten steel ingot mold 4 and the upper end of the vacuum chamber 3 .

[0039] In order to ensure that the superheat of the molten steel is effectively reduced in use, the side wall of the vacuum chamber 3 is provided with at least one group of cooling air passage holes 6, and the cooling air passage holes 6 are symmetrically arranged up and down.

[0040] In order to reduce the oxygen content during use, thereby reducing the secondary oxidation of refined slag and molten steel, the ventilation pipe is a combustible gas channel 2-1 along the inner layer of the cover of the intermediate ladle 2, and an argon channel 2-2 is provided along the outer layer of the combustible gas channel.

[0041] In order to assist in blowing in a small amount of argon gas during use to form a slight positive pressure and prevent the entry of external oxygen, a retaining wall 7 is provided in the intermediate ladle 2 at the location of the combustible gas channel 2-1, and the combustible gas channel 2-1 extends to the bottom of the retaining wall 7.

[0042] In order to ensure that the argon protection curtain is formed below the baffle wall 7 in the state of argon being introduced, and to avoid the entry of outside oxygen, a gas resistance layer 8 is arranged on the bottom surface of the baffle wall 7 close to the inner ring of the combustible gas channel 2-1, and the gas resistance layer 8 is an inward recessed layer. The lowest plane of the argon channel 2-2 extends to one half of the height of the gas resistance layer 8, the outlet of the argon channel 2-2 is arc-shaped, and the outlets of the argon channel 2-2 are arranged in a clockwise circumferential manner.

[0043] The outlet of the argon channel 2-2 faces the top surface of the gas resistance layer 8.

[0044] In order to facilitate the reduction of the temperature of the molten steel in the use state and accelerate the cooling speed of the molten steel, a part of the combustible gas channel 2-1 in the intermediate ladle 2 is located above the molten steel surface, and a part is located below the molten steel surface.

[0045] A part of the combustible gas channel 2-1 in the intermediate ladle 2 is located below the molten steel surface, and the steel long liquid pipe is made of the same material as the molten steel, and melts during the pouring process, which is equivalent to adding cold iron into the pouring molten steel, and accelerates the cooling speed of the molten steel.

[0046] A use method of a secondary oxidation protection device for a ladle molten steel, comprising the following steps:

[0047] The top of the intermediate ladle 2 is inserted into a gas passage, and the gas passage and the ladle cover of the intermediate ladle 2 are sealed, combustible gas is introduced into the passage during the standing and pouring processes, and the combustible gas and the oxygen in the ladle headspace undergo oxidation reaction to consume the oxygen in the headspace.

[0048] Meanwhile, a gas resistance layer 8 is arranged on the bottom surface of the baffle wall 7 close to the inner ring of the combustible gas channel 2-1, and the gas resistance layer 8 is an inward recessed layer, the lowest plane of the argon channel 2-2 extends to one half of the height of the gas resistance layer 8, the outlet of the argon channel 2-2 is arc-shaped, and the outlets of the argon channel 2-2 are arranged in a clockwise circumferential manner.

[0049] The outlet of the argon channel 2-2 faces the top surface of the gas resistance layer 8, a small amount of argon is blown into the argon channel 2-2 to form a slight positive pressure, and the entry of outside oxygen is avoided.

[0050] After the refining and smelting of the ladle are completed, the conventional treatment and the insertion of the pipe at the top to blow in combustible gas are respectively performed, and after the ladle pouring is completed, the residual refining slag is taken for FeO content chemical analysis. The results are shown in the following table, and it can be found through comparison that the blowing in of combustible gas can effectively reduce the oxidizability of the ladle molten steel.

[0051] The comparison effect is shown in the following table:

[0052]

[0053] The present application provides a method for reducing secondary oxidation of molten steel in a ladle by combustion, which can reduce the oxygen content in the headspace of the ladle, thereby reducing the secondary oxidation. Mainly by inserting a pipeline into the top of the ladle cover, blowing in combustible gas, chemical reaction, consuming the oxygen content in the headspace of the ladle, thereby reducing the oxygen partial pressure, reducing the secondary oxidation of the molten steel contact surface of the ladle. The method is simple and easy to implement, and the effect is obvious.

[0054] It will be apparent to those skilled in the art that the application is not limited to the details of the above-exemplified embodiments but can be implemented in other concrete forms without departing from the spirit or essential characteristics of the application. The embodiments should therefore be considered in all respects as illustrative and not restrictive, the scope of the application being defined by the appended claims rather than by the above description, and it is therefore intended that all changes and modifications that come within the meaning and range of equivalency of the claims are resolvable thereunder. Any reference signs in the claims should not be construed as limiting the claims concerned.

[0055] Furthermore, it should be understood that, although the present specification is described in terms of embodiments, not every embodiment contains only one independent technical solution, and the present specification is described in this way only for the sake of clarity, and those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that those skilled in the art can understand.

Claims

1. A ladle liquid steel secondary oxidation prevention device, characterized in that: It comprises a refining liquid steel ladle (1) connected with a tundish (2) whose top is inserted into a snorkel pipe, wherein the snorkel pipe and the tundish cover are sealed; The snorkel pipe is arranged along the center of the tundish cover to the outer circumference; The tundish (2) is directly connected with a vacuum chamber (3) below, and a liquid steel ingot mold (4) is arranged in the vacuum chamber (3); A long liquid pipe (5) is arranged between the liquid steel ingot mold (4) and the tundish (2); At least one group of cold gas passage holes (6) are arranged on the side wall of the vacuum chamber (3) and are symmetrically arranged up and down; The snorkel pipe is a combustible gas passage (2-1) along the inner layer of the tundish cover, and an argon gas passage (2-2) is arranged along the outer layer of the combustible gas passage; A retaining wall (7) is arranged in the tundish (2) at the position of the combustible gas passage (2-1), and the combustible gas passage (2-1) extends below the retaining wall (7); A gas resistance layer (8) is arranged on the bottom surface of the retaining wall (7) close to the inner ring of the combustible gas passage (2-1), and the gas resistance layer (8) is an inward recessed layer; The lowest plane of the argon gas passage (2-2) extends to one half of the height of the gas resistance layer (8), the outlet of the argon gas passage (2-2) is arc-shaped, and the outlets of the argon gas passages (2-2) are arranged in a clockwise manner along the circumference; The outlets of the argon gas passages (2-2) face the top surface of the gas resistance layer (8); Part of the combustible gas passage (2-1) in the tundish (2) is above the liquid surface of the liquid steel, and part of it is between the liquid surfaces of the liquid steel.

2. The device for preventing secondary oxidation of molten steel in a ladle according to claim 1, characterized in that: The long liquid pipe (5) extends below the liquid surface in the liquid steel ingot mold (4).

3. The ladle molten steel secondary oxidation preventing device according to claim 2, characterized in that: The liquid steel ingot mold (4) and the upper port of the vacuum chamber (3) are left with 20-30 cm.

4. A method of using the ladle liquid steel secondary oxidation protection device according to claim 3, characterized in that: It comprises the following steps; The top of the tundish (2) is inserted into the snorkel pipe, wherein the snorkel pipe and the tundish cover are sealed, combustible gas is introduced into the pipe during the standing and casting process, and the combustible gas and the oxygen in the tundish headspace undergo oxidation reaction to consume the oxygen in the headspace; Meanwhile, the bottom surface of the retaining wall (7) is close to the inner ring of the combustible gas passage (2-1), and a gas resistance layer (8) is arranged thereon, which is an inward recessed layer, the lowest plane of the argon gas passage (2-2) extends to one half of the height of the gas resistance layer (8), the outlet of the argon gas passage (2-2) is arc-shaped, and the outlets of the argon gas passages (2-2) are arranged in a clockwise manner along the circumference; The outlets of the argon gas passages (2-2) face the top surface of the gas resistance layer (8), a small amount of argon gas is blown through the argon gas passage (2-2) to form a slight positive pressure, and the entry of external oxygen is avoided.

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