JP3182119B2 - Method and apparatus for removing carbon, silicon, manganese and sulfur from molten high carbon iron metal - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION The present invention relates to a method for removing carbon, silicon, manganese and sulfur from molten high carbon iron metal and an apparatus for carrying out the method. More particularly, the present invention relates to a method and an apparatus for removing carbon, silicon, manganese and sulfur as a pretreatment step of a molten hot metal produced in a reaction vessel such as a blast furnace or a ladle usually used in an iron plant.

[0002]

2. Description of the Related Art In order to convert hot metal from a blast furnace or cast iron metal from a cupola (both of which are hereinafter referred to as hot metal) into steel, it is necessary to remove carbon, silicon and manganese present in the hot metal. Must. Similarly, there is a need to reduce the sulfur content of hot metal to produce better or more valuable steel.

[0003] The removal of carbon, silicon and manganese from hot metal in steel plants is usually carried out in steel making units such as basic oxygen furnaces, open hearth furnaces and the like. If a hot metal pretreatment step is required, the metallurgical work to be performed in these steelmaking units to remove carbon, silicon and manganese must be carried out during that pretreatment and before the hot metal is processed in the steelmaking unit. Has been partially done. In this process, although expensive steelmaking units are used,
Removal of the above substances has been promoted, high productivity can be achieved, and high-quality, high-value steel production has been aimed at.

[0004] In the pre-treatments used hitherto, the removal of carbon, silicon and manganese is achieved by the addition of mill scale and / or by oxygen lancing of the hot metal contained in the ladle or the reaction vessel. Is done. In such a process, each time the removal of silicon and sulfur requires continuous slag removal, the ladle or hot metal movement is stopped, and the removal is performed in a separate process or vessel.

[0005] Also, in such pretreatment steps, the amount of silicon that can be removed is rather limited (up to about 0.2 percent). On the other hand, although higher silicon removal or carbon removal can be produced by oxygen lancing, iron oxide forms a slag phase of iron oxide due to loss of iron, and generates a large amount of odor.

[0006] At present, in the removal of sulfur from hot metal, since magnesium is the most effective substance for removing sulfur, means for introducing magnesium into molten hot metal is often used.

[0007] However, in the above-mentioned prior art in which magnesium is introduced, the solubility of magnesium in iron is low. In addition, the efficiency of magnesium recovery and treatment when using pure or nearly pure magnesium is extremely low. This is because magnesium floats on the surface of the molten metal due to its low density until magnesium precipitates in the desulfurization reaction. Further, magnesium is flammable and thus easily burns.

When magnesium is charged into the hot metal, that is, as soon as the magnesium comes into contact with the hot metal, it evaporates. This evaporation greatly increases the volume of magnesium, so that the dosing of magnesium causes an explosive and violent reaction, with most of the hot metal being discharged from the reactor at a high rate. Such a magnesium treatment method is very dangerous. Moreover, this treatment is not reliable because the contact time between magnesium and hot metal is very short.
Thus, the amount of sulfur removed is practically negligible. As described above, it is dangerous to introduce magnesium into hot metal contained in a bell-shaped crucible or a crucible having an open end, since an extremely violent reaction occurs. In order to avoid this danger, when magnesium is introduced, it may be introduced as an alloy in the form of, for example, mag-coke, a nickel-magnesium alloy, or an Fe-Si-Mg alloy. The reaction in this case is somewhat controlled, and violent reactions can be suppressed.

However, the method of removing sulfur using a nickel-magnesium alloy or an Fe-Si-Mg alloy is expensive and therefore difficult to employ, and a system for introducing magke coke becomes very large and expensive. It should be noted that

However, it is possible to remove sulfur from the hot metal if the source of magnesium vapor is maintained such that the reaction can be carried out reliably and continuously in the hot metal. At present, one of the widely used desulfurization techniques is to suspend granulated magnesium coated with a less reactive material in a carrier gas such as nitrogen and then use a specially designed dispenser. There is a method of generating a source of magnesium vapor by a technique of injecting the magnesium coated particles or powder into hot metal. However, in this technology, there is a problem of obtaining high-purity nitrogen, a problem that the unreacted magnesium is lost as a vapor, which makes the reaction with nitrogen chemically likely, and also, it does not completely react with sulfur in the hot metal. There is a problem that it is physically transported with nitrogen when foaming. For this reason, the utilization efficiency of magnesium for removing sulfur decreases.

As another method of generating a source of magnesium vapor, a porous refractory brick material in which magnesium is preheated is produced by immersing the material in molten magnesium, and the refractory brick material is then There is also a method of separating the magnesium immersed in the refractory brick material by pouring it into molten iron.

Alternatively, there is a method called "converter" in which magnesium is put into a special chamber provided at the bottom of a reaction vessel. In this method, magnesium is inserted into its special chamber when the converter is empty. Thereafter, the converter is filled with hot metal and a molten magnesium, and magnesium is separated through the hot metal to perform desulfurization. However, this technique also has a problem that requires expensive capital equipment.

In still another method, after the magnesium is connected to the plunger head at its open end, the open end of the plunger head is closed with a plug, and a hole is provided in the wall of the plunger head. There is a method in which after the plunger is immersed and held in the hot metal, magnesium vapor is released through the holes. This method requires a new plunger for each treatment.

In still another method, the open end of the plunger head is closed with a disc-shaped piece made of a refractory brick material. The plunger head is brought into contact with the bottom of the ladle and makes physical contact with it to press the bottom. Although this discharge operation process is simple and attracting attention, the plunger head used in such a process is considerably expensive due to the use of expensive materials and the high assembly costs required for its manufacture. It is inevitable. Moreover, the plunger operation is often unsuccessful because the plunger head breaks before the end of the reaction. Also, in such a plunger operation, the plunger head will be damaged after processing for one or more reasons. First, due to the thermal expansion of the plunger rod and head, a mechanical load is placed on the plunger head if it is pressed against the bottom of the ladle during ejection. Second, because the plunger head is in physical contact with and pressed against the bottom of the ladle, the ladle vibrates due to the stirring of the hot metal generated by the expanding magnesium vapor, and the plunger head is mechanically attached to the plunger head. Load is applied. Since the plunger cannot be reused and is itself somewhat expensive, the use of a new plunger for each plunge increases the cost of desulfurization by magnesium treatment, which leads to higher costs.

[0015]

By the way, in the above-mentioned prior art, the removal of silicon, manganese and carbon all involves several separate steps, and these methods also require a re-ladle treatment. In addition, there is a problem that the process of removing silicon, manganese and carbon is complicated and expensive due to the necessity of de-slag treatment.

The reasons for using several steps and deslagging as described above are explained as follows. For removing silicon, manganese and carbon from molten metal for steel production, the potential of oxygen in hot metal is extremely high (~ 1).
0 ^-4 ). On the other hand, removal of sulfur requires an extremely low potential of oxygen (（10 ⁻¹³ ). In other words, the removal of silicon from hot metal requires an oxidizing atmosphere, while the removal of sulfur requires a highly reducing atmosphere. As a result, it is generally believed that silicon and sulfur present in the hot metal cannot all be removed together in the same reaction vessel.

At present, from a hot metal in a single reaction vessel without de-slag and / or re-ladle processing, silicon,
There is no known method for removing manganese and carbon together with sulfur, and there is a need for a method and apparatus that can realize this.

[0018] The applicant of the present invention has proposed that from a hot metal in a single reaction vessel, silicon,
If carbon, manganese and sulfur are removed together, costs will be reduced and temperature drops will be minimized and the number of operations reduced as ladle shutdowns can be reduced in manufacturing plants. And smooth operation.

The present invention has been made in view of such circumstances, and it is effective and effective to remove all of silicon, manganese and carbon from molten high carbon iron metal in a single reaction vessel. It is an object of the present invention to provide a method and an apparatus which can be realized economically and without causing a complicated and troublesome reaction, and without generating odor and a large temperature drop. Further, in the present invention, in the step of removing all of silicon, manganese, carbon and sulfur from high-carbon iron metal together, the amount of sulfur removed from the hot metal from the generated sulfur-rich slag is returned to the hot metal. Is negligible even after the hot metal has been in contact with the slag for a long time, or even after being mixed with the slag by re-laundering or by being charged into the BOF It is another object of the present invention to provide a method and an apparatus capable of increasing the amount of hot metal in a reaction vessel by the method of the present invention.

[0020]

SUMMARY OF THE INVENTION To achieve the above objects, the method of the present invention comprises the steps of reducing the concentration of silicon, carbon, manganese from molten high carbon iron metal contained in a single reaction vessel. And a method for removing sulfur, after adding a mixture of a material containing iron oxide and a flux to a reaction vessel,
To this mixture, add hot metal of molten iron metal with high carbon,
After oxidizing silicon, carbon and manganese to obtain a slag floating on the surface layer of the hot metal, a plurality of through holes are provided in a lower portion of the side wall, and a plunger having a plunger head having a closed bottom end is used. With the plunger head containing metallic magnesium, the plunger is lowered in the hot metal until the plunger head contacts the bottom of the reaction vessel, and the plunger head contacts the bottom of the reaction vessel at the same time. Raising the plunger head to a predetermined position so as to form a gap in the range of 5 to 50 mm between the bottom of the reaction vessel and the plunger head, and passing magnesium vapor into the hot metal through the through hole. The molten iron in the reaction vessel is agitated by releasing it gradually to remove sulfur from the molten iron. While mixing the existing unreacted iron oxide and causing agitation during the release of magnesium vapor to further oxidize silicon and manganese, the iron oxide is further reduced to iron and the reaction is completed. At which point the slag is removed.

In the method of the present invention, it is preferable to selectively use iron ore, blue dust, mill scale, and sintered returns as the material containing iron oxide. It is preferable that limestone, fluorite, and rice husk are selectively used for the mixture. Further, aluminum may be used together with magnesium metal as a desulfurizing agent.

In the step of preparing a mixture of a material containing iron oxide and a solvent, preheating is preferably performed at a temperature in the range of 200 to 400 ° C.

Further, it is preferable that the plunger head can be lifted up to a height higher than the height at which the plunger head comes into contact with the bottom of the reaction vessel.

According to the method of the present invention, silicon, carbon and manganese are removed from the hot metal by adding a material containing iron oxide to the hot metal. The iron oxide present in the material partially reacts with the silicon, carbon, and manganese present in the hot metal and is reduced by itself to produce iron that combines with the molten hot metal. Unreacted iron oxide then becomes a slag phase and floats on the surface of the hot metal. The iron oxide present in the slag phase is further reduced to iron by the intimate mixing created by the perturbations created during the discharge of magnesium to achieve the desulfurization reaction. As a result, some more iron oxide is again reduced to iron and mixed with the hot metal. This increases the amount of iron present in the reaction vessel and achieves decarbonization, silicon removal, manganese removal and sulfur removal from the hot metal in the same ladle.

As described above, the method of the present invention is based on a completely new method of promoting reduction or oxidation at two different places in the same reaction vessel. Thus, the removal of sulfur takes place at the bottom of the reaction vessel, while the removal of silicon, manganese and carbon takes place in the top layer of hot metal where slag is present. Therefore, according to the present invention, completely different reaction conditions can be simultaneously achieved in the same reaction vessel.

An apparatus according to the present invention is an apparatus for performing the method according to any one of claims 1 to 6, wherein the reaction vessel has an open top; a cover covering the opening of the reaction vessel; A side wall provided with a plurality of through holes at a lower portion, an upper wall, a plunger head having an open end facing the upper wall which can be opened and closed by a lid, and fixed to the upper wall of the plunger head; A plunger rod installed through the cover, wherein the plunger head and the plunger rod are integrally movable vertically with respect to the cover; and the plunger head is provided at the bottom of the reaction vessel. At this point, the plunger is lifted so that a predetermined distance is maintained between the bottom of the reaction vessel and the plunger head, and the plunger is lifted. There characterized by having a lock-and-lifting means which is adapted to be locked to the cover.

The plunger rod is composed of a lower plunger rod whose core is steel and whose core is coated with a refractory material, and an upper plunger rod which is formed of steel and has a groove formed on the outer periphery of the upper end. And the lid is provided with a step which fits into the open end of the plunger head,
The height of the step is formed larger than the distance that the plunger head can be lifted by the lock undrift means, and the cover is provided with a ventilation pipe for discharging gas in the reaction vessel, and The lock undrift means is provided on the cover,
And, while the plunger rod penetrating through the cover is penetrated, a substrate having an opening formed to allow the vertical movement is formed, and a substrate inclined near the upper plunger rod is inclined with respect to the substrate. A block having a surface is fixed, and a groove that fits with the groove of the upper plunger rod is provided, and the upper plunger rod slides on the inclined surface with the vertical movement of the plunger. And a pair of jaws for lifting the groove with the groove fitted.

Further, it is desirable that the inclined surface of the block body is formed in a range of 30 degrees to 60 degrees with respect to the substrate.

According to the apparatus of the present invention, when the plunger head of the plunger movably attached to the cover of the reaction vessel comes into contact with the bottom of the ladle, a gap is formed between the bottom of the ladle and the plunger head. It is formed and is based on a lock-and-drift means configured on the principle of locking the plunger to the cover.

This lock and lift configuration can be achieved in various ways. In a preferred embodiment,
This can be achieved by two jaws that can move towards each other on a plane of inclination in the range of 30 to 60 degrees formed on the top of the ladle cover. The jaws slide on the sloped surface of the block to grasp the plunger rod, lift the plunger rod in that position, and then lock the plunger rod to the ladle cover. When the jaw fixed on the cover is fitted to the plunger rod, the structure is integrated with the cover of the ladle. Jaw movement is controlled electromechanically, pneumatically, or hydraulically.

According to the present invention, the plunger can be pressed against the bottom of the ladle by vertically moving the opening provided in the cover of the ladle at the upper end of the plunger. When the plunger head comes into contact with the bottom of the ladle, the lock-and-drift means is activated by a suitable mechanism and drive. As a result, the plunger is raised and then locked into the steel shell of the ladle cover. Since the lock-and-drift means is firmly fixed to the ladle cover, the plunger is also integrated.

[0032]

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

FIG. 1 is a sectional view showing the structure of an embodiment of the present invention. FIG. 2 is a front view for explaining a main part thereof, and FIG. 3 is a plan view thereof.

The apparatus according to the present embodiment includes a ladle 3 having an open top and a steel ladle cover 2 covering the opening of the ladle 3. The ladle cover 2 has an inner surface coated with a refractory material. The ladle cover 2 is usually given a weight so that the cover is sufficiently heavy so that the ladle cover 2 has a structure that covers the opening of the ladle 3 reliably.
The magnesium vapor cannot lift the plunger 20 together with the ladle 3. . Alternatively, the ladle cover 2 is lightened (the structural strength is sufficient) and the ladle cover 2 is locked with the substrate portion or the structure, or the ladle 3 is pressed from above with an air / hydraulic cylinder. The ladle cover 2 may be mechanically rocked by another solid structure while properly installed on the ground. As described above, the ladle cover 2 is securely mounted on the ladle 3 by appropriate means. In the configuration of FIG. 1, the four corners of the ladle cover 2 are fixed to the hooks 7 by ropes. Further, the ladle cover 2 is provided with a ventilation pipe 8 for discharging exhaust gas and odor generated during the reaction.

A side wall 1b provided with a plurality of through holes 1d in the lower portion, an upper wall 1a, and a removable disk-shaped lid 1c having a stepped open end facing the upper wall 1a can be freely opened and closed. By means of a plunger head 1 and a threaded joint on the upper wall 1a of the plunger head 1 (or by a cotter of a fixing bolt).
The plunger 20, consisting of the fixed lower plunger rod 6 and the upper plunger rod 5 connected to the lower plunger rod 6, is connected by suitable means to form a single integrated, so-called integrated structure. Has become.
The rod portion is vertically movable with respect to the ladle cover 2 while penetrating the ladle cover 2. This vertical movement was constituted by a guide post 9 having two pairs of rollers detachably welded and fixed on the top of the ladle cover 2 and two guide plates 10 sliding along the guide post 9. Vertical movement is ensured by the plunger guide system.

The plunger head 1 is provided with a weight so that the plunger head 1 is controlled so as to smoothly enter the ladle 3 containing the hot metal, and when the weight contacts the bottom of the ladle 3. It is adjusted so that it is not damaged. The plunger head 1 is controlled so that the distance from the bottom of the ladle 3 is in the range of 5 to 50 mm. The step provided on the lid 1c has a diameter slightly smaller than the diameter of the concave portion of the cylindrical plunger head 1,
The diameter of the lid 1c is equal to or larger than the outer diameter of its plunger head 1. The step fits into a recess in the plunger head 1. The lid 1c stays in place at the bottom of the ladle 3, and during the process the plunger is 5 to 50
mm, the open end of the plunger head 1 is kept closed. The step provided on one surface of the lid 1c has a height of 25 to 50 mm, and the step allows the plunger 20 to be lifted by the lock and unlift mechanism described later while the plunger 20 is lowered and during the reaction. After that, the lid 1c is prevented from slipping out. Note that the height of this step is formed larger than the distance that the plunger 20 can be lifted by the lock-and-drift mechanism. In order to positively fix the lid inside the plunger head, a step with a height of 25 to 50 mm of the lid is provided. While the plunger is down,
It also prevents the lid from slipping out after the lock and lift assembly lifts the plunger during the reaction. Also,
The upper plunger rod 5 is made of steel and has a plurality of horizontal circular grooves 12 formed on the outer periphery thereof. The balance weight 4 is attached to the upper end of the upper plunger rod 5. In addition, the ladle cover 2 can be lifted by the hook 7. On the other hand, the core inside the lower plunger rod 6 is made of steel, and has a structure in which the outside is coated with a refractory material.

The lock-and-drift assembly 11, which constitutes the lock-and-drift mechanism, includes the above-described grooved upper plunger rod 5, the substrate 13, and a 45-degree inclined block fixed on the substrate 13. 15, a motor 16 with gears, a slide jaw 14, and a counterweight 4.

An opening is formed in the substrate 13, and the upper plunger rod 5 can freely move vertically through this opening and the opening formed in the ladle cover 2. Further, the pair of slide jaws 14 has a configuration in which horizontal semicircular grooves are provided on the inner cylindrical surfaces facing each other, and fits with the grooves 12 provided on the upper plunger rod 5. Combine. This slide jaw 14 is
6, the plunger 20 slides on the inclined surface of the inclined block 15 with the vertical movement of the plunger 20, and is lifted in a state where the groove 12 of the upper plunger rod 5 and the groove of the slide jaw 14 are fitted. Has become. This sliding operation is performed in an electromechanical manner in the present embodiment, but is not limited to this, and is performed by an actuator that performs a reciprocating motion in a pneumatic or hydraulic manner. Further, the lifted plunger 20 is locked to the ladle cover 2. Further, the balance weight 4 is adjusted such that when the hook 7 is lowered, the plunger 20 gradually descends into the hot metal.

The inclination angle of the inclined portion 15 with respect to the substrate may be in the range of 30 ° to 60 °.

When the plunger 20 is lowered by the lock-and-lift assembly 11 having the above structure and the plunger head comes into contact with the bottom of the ladle 3, the plunger 20 can be locked and lifted. Here, by the lock undrift assembly 11,
A gap is formed between the plunger head 1 and the bottom of the ladle 3, this gap being formed by the oscillation of the ladle 3 during discharge or a heated plunger fixed to the bottom of the ladle 3. It is formed by the thermal expansion of 20, which prevents the movement of the force of the plunger head 1.

The lid 1c closes the open end at the bottom of the plunger head after the magnesium is placed inside the plunger head 1. Thereby, the plunger head 1
While it is lowered and while it is held at a distance of 5 to 50 mm above the bottom of ladle 3, retains the magnesium inside to prevent direct contact between the molten metal and magnesium.

When the lock and lift system is not operating, there is sufficient clearance between the slide jaw 14 and the upper plunger rod 5 to allow the upper plunger rod 5 to move vertically. Have been.

In this embodiment, after the plunger head 1 is gradually lowered and put on the bottom of the ladle 3,
An electromechanical actuation system has been applied which switches on the electric drive. This imparts a tilting movement to the slide jaw 14 through appropriate mechanisms and signaling. The slide jaw 14 and the grooved upper plunger rod 5 are designed so that, after locking, the shaft is lifted according to the height of the depth of the groove.
Also, various limit switches are provided to ensure system overload and security aspects.

As a result, the hot metal in the ladle is treated by a steady flow of magnesium vapor flowing out of the through hole of the plunger head 1. If the pressure of the magnesium vapor increases inside the plunger head 1 and an unexpected situation occurs, the magnesium vapor flows out through the gap between the plunger head 1 and the bottom of the ladle 3, so that the control can be performed. A highly reliable magnesium treatment of the hot metal that has been performed can be performed.

An embodiment of the method of the present invention will be described using the apparatus having the above configuration. The method will be described with time in a to h below. a. After adding a mixture of a material containing iron oxide and a flux to ladle 3, b. To the mixture is added hot metal of molten iron metal of high carbon to oxidize silicon, carbon and manganese to obtain some gaseous products and slag floating on the surface of the molten metal, c. A plurality of through holes 1d are provided in the lower portion of the side wall 1b, and a plunger 20 having a plunger head 1 with a closed bottom end is used, and the plunger head 1 contains metallic magnesium. D. Lowering the plunger 20 through the hot metal until the plunger head 1 contacts the bottom of the ladle 3; e. At the same time that the plunger head 1 comes into contact with the bottom of the ladle 3, the bottom of the ladle 3 and the plunger head 1
The plunger head 1 is pulled up to a predetermined position so as to form a gap in the range of 5 to 50 mm between f. And f. After gradually releasing the vapor of magnesium into the hot metal through the through hole 1d to generate a stirring in the hot metal in the ladle 3 to perform desulfurization of the hot metal, g. While mixing the hot metal and the unreacted iron oxide present in the slag, stirring is caused during the release of the magnesium vapor, and the silicon and manganese are further oxidized to further reduce the iron oxide. Iron, h. At the end of the reaction, the slag is removed.

In this method, iron ore, blue dust, mill scale, and sintered returns may be selectively used as the material containing iron oxide.

Further, limestone, fluorite and rice husk may be selectively used as a flux. Further, magnesium metal may be used together with aluminum as a desulfurizing agent.

Further, in the step of preparing a mixture of a material containing iron oxide and a flux, it is desirable to perform preliminary heating in a temperature range of 200 to 400 ° C.

The plunger head 10 is a ladle 3
It is desirable to be configured to be able to lift to a height greater than the height to be lifted at the same time as it comes into contact with the bottom portion of the head. <Examples> Examples of the present embodiment will be described in further detail.

The mixture comprising the material containing iron oxide is heated to a temperature of from 200 to 400.degree. This mixture is placed on ladle 3 and hot metal at a temperature of 1350 to 1500 ° C. is added to the mixture in ladle 3. Here, a reaction between the hot metal and the mixture occurs.

Next, magnesium metal is put in a can,
The can is inserted into the plunger 20. Thereafter, the plunger head 1 is closed by the disc-shaped plunger lid 1c having a step inside the plunger head 1. The plunger lid 1c is fixed to the plunger head 1. Thereafter, the ladle cover 2 is securely placed on the ladle 3.
Next, the plunger 20 is lowered until the plunger head 1 contacts the bottom of the ladle in the hot metal in the ladle 3. The upward motion of the expanding magnesium vapor creates a stirrer in the hot metal in the ladle. As soon as the bottom is reached, the plunger 20 is pulled up and between 5 and 50 between the bottom of the ladle 3 and the plunger head 1.
Make a gap in the range of mm. This is achieved by switching the drive and moving the slide jaws 14. This agitation in the metal produces an intimate mixture of the hot metal silicon, manganese, and carbon with the unreacted iron oxide contained in the slag on top of the metal. The removal of silicon, manganese, and carbon and the recovery of iron are achieved by the reduction of iron oxide in the slag phase and are performed continuously during the reaction process. The reaction of magnesium vapor with hot metal produces excellent desulfurization because the magnesium vapor interacts tightly as it rises in a controlled manner through the hot metal. After discharging the magnesium, the plunger is removed and the ladle cover 2 is removed from the ladle 3.
The temperature drop due to magnesium discharge is negligible. As a result of analyzing the hot metal after the reaction was completed, it was confirmed that silicon, manganese, carbon, and sulfur were removed.

The slag is then removed in a conventional manner by a deslagging unit, and the hot metal can be introduced into a basic oxygen furnace to convert it to low sulfur, high quality steel.

The fact that the conversion of sulfur from slag to metal in the present invention is negligible is apparent from the following. That is, after the magnesium was discharged, the ladle 3 was kept on standby for 2 hours. Thereafter, the entire slag and the hot metal were charged into another ladle, and the sulfur-rich slag and the hot metal were mixed intimately. Even after such waiting and mixing, the sulfur in the hot metal did not increase. This result, unlike all other desulfurization steps, in the present example,
It proves that such long waiting and mixing did not result in sulfur reversal.

[0054]

The present invention is configured as described above, so that the following effects can be obtained. 1. Finally, with only one de-slag, it is possible to simultaneously de-siliconize, de-manganese, de-carbonize and desulfurize hot metal in a single vessel, which simplifies the process and Can be done economically. Further, the present invention can be applied to a system for transferring hot metal in a steelmaking plant from steelmaking to a steelmaking unit, and more quickly and without using a mixer unit that is used to store hotmetal toward a steelmaking unit in a steelmaking plant. Conversion can be achieved. 2. The reaction during the process is controlled and there is no risk of the usual dangers of the process of discharging magnesium. 3. The pretreatment step conventionally performed, that is, the step of removing slag generated by desiliconization and demanganese prior to desulfurization can be omitted. 4. The introduction of magnesium into the molten metal can be controlled smoothly. 5. Extremely high desulfurization can be achieved. 6. There is little sulfur reversal in the present invention in all other steps after the hot metal has been desulfurized. Further, the temperature drop during the processing was negligible. Because of these, it is not necessary to use a mixer inside the steelmaking plant, so that the pretreated hot metal can be transported flexibly. 7. Since the temperature drop is low in the method of the present invention, desulfurization can be performed even when the temperature of the hot metal is low.
In addition, the hot metal after the pretreatment can be charged into the steelmaking unit at a higher temperature, and high productivity of steel can be obtained. 8. Very little magnesium is used to achieve a given amount of desulfurization. 9. Odor can be prevented from occurring, and a high degree of silicon removal can be achieved. 10. Since this method uses an extremely inexpensive oxidizing agent such as iron ore, sintered fines and mill scale, the cost can be reduced. 11. The method recovers most of the iron from materials containing iron oxide and converts it to hot metal, and the value of the recovered iron effectively supports the cost of desulfurization and makes the process even cheaper. 12. Locking and lifting of the plunger used to prepare the hot metal prevents damage to the plunger and its head due to mechanical damage and allows their repeated use, reducing cost, maintenance and operating problems. 13. Since the plunger head is closed with a lid throughout the magnesium discharge reaction, a vigorous reaction between the hot metal and magnesium is avoided. 14． The apparatus of the invention used allows the same plunger head to be used repeatedly without breakage or to provide a very controlled release of magnesium vapor through the hot metal.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a configuration of an embodiment of the present invention.

FIG. 2 is a front view for explaining a main part of the embodiment of the device of the present invention.

FIG. 3 is a plan view for explaining a main part of the embodiment of the device of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Plunger head 1a Upper wall 1b Side wall 1c Lid 1d Through hole 2 Ladder cover 3 Ladder 4 Balance weight 5 Upper plunger rod 6 Lower plunger rod 7 Hook 8 Ventilation pipe 9 Guide post 10 Guide plate 11 Lock undrift set Solid 12 Groove 13 Substrate 14 Slide jaw 15 Inclined block 16 Motor 20 Plunger

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shirobadoura Benergy India Ranch 834002 Doranda (No address) Inside Steel Authority of India Limited Research and Development Center (72) Inventor Kedar Nas Pandi India Ranch 834002 Doranda ( (No address) Steel Authority of India Limited Research and Development Center (72) Inventor Baharat Chandra Roy India Lunch 834002 Doranda (No address) Steel Authority of India Limited Research and Development Center (72) Invention Party Om Prakash Sharma India Lunch 834002 Doranda (without address) Inside Steel Authority of India Limited Research and Development Center (72) Inventor Asim Kumar Sahu India Lunch 834002 Doranda (without address) Steel Authority of India Limited Research and Development Center (58) Field surveyed (Int. Cl. ⁷ , DB name) C21C 1/04 C21C 7/00 C21C 7/04 C21B 3/00

Claims (9)

(57) [Claims] A method for removing silicon, carbon, manganese and sulfur from molten high carbon iron metal contained in a single reaction vessel, the method comprising the steps of: After adding the mixture with the agent to the reaction vessel, add hot metal of high-carbon molten iron metal to this mixture, oxidize silicon, carbon, manganese, and obtain slag floating on the surface layer of the hot metal A plurality of through-holes are provided in the lower portion of the side wall, and a plunger having a plunger head having a closed bottom end is used. Lower the hot metal until it contacts the bottom of the reaction vessel, and at the same time that the plunger head contacts the bottom of the reaction vessel, the plunger head moves between the bottom of the reaction vessel and the plunger head. The plunger head is pulled up to a predetermined position so as to form a gap in a range of ~ 50 mm, and magnesium vapor is gradually discharged into the hot metal through the through-holes to thereby stir the hot metal in the reaction vessel. Then, the hot metal is desulfurized, and the unreacted iron oxide present in the hot metal and the slag is mixed, and while the steam of magnesium is being released, stirring is caused to occur to further separate silicon and manganese. A method for removing carbon, silicon, manganese and sulfur from a molten high carbon iron metal, wherein the iron oxide is further reduced to iron by oxidizing, and the slag is removed when the reaction is completed. 2. The molten high carbon iron metal to carbon and silicon according to claim 1, wherein iron ore, blue dust, mill scale, and sintered returns are selectively used as the material containing iron oxide. To remove manganese, sulfur and manganese. 3. The method for removing carbon, silicon, manganese and sulfur from molten high carbon iron metal according to claim 1, wherein limestone, fluorite and rice husk are selectively used as the flux. . 4. The method for removing carbon, silicon, manganese and sulfur from a molten high carbon iron metal according to claim 1, wherein magnesium metal is used together with aluminum as a desulfurizing agent. 5. The method according to claim 1, wherein in the step of preparing a mixture of a material containing iron oxide and a flux, preheating is performed in a temperature range of 200 to 400 ° C. A method for removing carbon, silicon, manganese and sulfur from molten high carbon iron metal. 6. The plunger head according to claim 1, wherein said plunger head comes into contact with the bottom of said reaction vessel and can be lifted to a height greater than said lifting height.
3. The method for removing carbon, silicon, manganese and sulfur from a molten high carbon iron metal according to 3, 4, or 5. 7. An apparatus for carrying out the method according to claim 1, wherein the reaction vessel has an opening at an upper part; a cover covering an opening of the reaction vessel; and a plurality of through holes at a lower part. , A plunger head having an open end opposed to the upper wall which can be opened and closed by a lid, and fixed to the upper wall of the plunger head and installed through the cover. A plunger rod, the plunger head and the plunger rod being integrally movable vertically with respect to the cover; and when the plunger head is located at the bottom of the reaction vessel, The plunger is lifted so that a predetermined distance is maintained between the bottom of the reaction vessel and the plunger head, and the plunger is locked to the cover. Apparatus for removing carbon, silicon, manganese and sulfur from the molten high carbon ferrous metal, characterized in that a lock-and-lifting means which is configured to be. 8. The plunger rod comprises a lower plunger rod whose core is steel and whose core is coated with a refractory material, and an upper plunger rod formed of steel and having a groove formed on the outer periphery of an upper end. And a step is formed on the lid so as to fit into the open end of the plunger head, and the height of the step is formed to be greater than a distance at which the plunger head can be lifted by the lock and unlift means. The cover is provided with a ventilation pipe for discharging gas in the reaction vessel, and the lock-and-drift means is provided on the cover, and
While the plunger rod penetrating the cover is penetrated, a substrate having an opening that allows the vertical movement is formed, and an inclined surface inclined with respect to the substrate on a substrate near the upper plunger rod. The plunger has a groove fixed thereto, and is provided with a groove that fits into the groove of the upper plunger rod, and slides on the inclined surface with the vertical movement of the plunger, thereby forming a groove in the upper plunger rod. 8. The apparatus for removing carbon, silicon, manganese and sulfur from a molten high carbon iron metal according to claim 7, further comprising a pair of jaws for lifting with said groove fitted. 9. The inclined surface of the block is arranged with respect to the substrate.
9. The apparatus for removing carbon, silicon, manganese and sulfur from molten high carbon iron metal according to claim 8, wherein the apparatus is formed in a range of 30 degrees to 60 degrees.