KR102444944B1 - Foaming and calming method of discharged slag and refining equipment used therefor - Google Patents

Abstract

It is a method for calming the foaming of discharged slag when discharging slag from the refining reaction vessel to the slag receiving vessel, and adding a substance having a viscosity reducing effect as a foaming calming agent so as to stay in the upper surface layer of the slag discharged to the slag receiving vessel Foaming calming method of discharged slag, characterized.

Description

Foaming and calming method of discharged slag and refining equipment used therefor

The present disclosure relates to a method of calming the foaming of discharged slag, that is, a method of calming the foaming of discharged slag upon discharge of the slag from a refining reaction vessel such as a converter to a slag receiving vessel.

After desiliconization or dephosphorization of molten iron in the converter, by tilting the converter, a part of the slag from the furnace is discharged from the furnace while leaving the molten iron in the converter, and the slag is discharged by flowing into the slag discharge ladle arranged below. As the main component, there is a method of continuously refining by adding auxiliary materials such as CaO).

In this method, the slag is easily discharged by forming (bubbling) the slag in the converter to increase the volumetric volume of the slag, thereby securing the slag discharge. Here, the foaming of the slag occurs when carbon (C) in molten iron and iron oxide (FeO) in the slag react to generate carbon monoxide (CO) gas, and the CO gas is held in the slag.

On the other hand, in the slag discharge ladle of the side which accommodates slag, the formed slag may overflow exceeding the capacity|capacitance of a slag discharge ladle. When the slag overflows, it causes troubles such as equipment damage and operation failure, so that the foaming calm in the slag discharge ladle is waiting so that the slag does not overflow, and the tilting speed of the converter, that is, the slag discharge speed is reduced. If the foaming subsidence becomes a problem and there is no choice but to reduce the slag discharge rate, it causes a decrease in productivity due to the prolonged slag discharge time. In addition, since the forming of slag in the converter is calmed down in the meantime and the bulk volume is reduced, the slag discharge property is deteriorated, thereby increasing the amount of slag carried in to the dephosphorization or decarburization treatment in the subsequent step, compound phosphorus, sloping (molten iron) or the liquid mass of the slag protrudes from the furnace furnace of the converter to the outside of the furnace).

Therefore, in order to prevent overflow of the foamed slag from the slag discharge ladle, various methods have been proposed in the prior art. As the simplest method, there is a method of increasing the capacity of the slag discharge ladle. However, there is a limit to the capacity expansion of the slag discharging ladle due to restrictions such as the space under the converter furnace and the transport of the slag discharging ladle, and when the number of slag discharging ladles is large, there are problems such as a huge facility investment. have.

Then, by injecting a foaming sedative into the slag discharge ladle, a method of calming the foaming is disclosed in Patent Documents 1, 2, and 3. As the foaming calming material, a substance in which a specific gravity adjusting material (slag, etc.) is added to a thermally decomposable material (pulp residue, organic matter such as plastic, oil such as engine oil, moisture, etc.) is used, and each of the substances constituting the soothing agent and its The mixing ratio, the size of the sedative, the specific gravity, the method of injection, etc. are prescribed. Since these are substances that rapidly generate gas by infiltrating the inside of the foamed slag, the impact of the gas generation is considered to contribute to breakage, ie, calming. However, in order to make it infiltrate into the inside of slag, it is accommodated in a container, or it shape|molds in a briquette shape, and it inject|throws-in in lump shape in many cases. Therefore, the reaction interface area decreases, the sedative effect may be low or the fluctuation|variation may be large, and it cannot necessarily be said that there exists a stable enough effect.

In addition, Patent Documents 4, 5, and 6 disclose methods of calming by spraying or blowing carbon material (coke, etc.) as a foaming sedative in a refining reaction vessel such as toffee car. Since carbon material has poor wettability with slag, it has an effect|action which destroys the liquid film between bubbles, and it aggregates and coalesces bubbles, and it is thought that it contributes to sedation. On the other hand, however, the carbon material and iron oxide in the slag react to generate CO gas that causes foaming, so that the effect may not be seen depending on the conditions.

In addition, as a soothing method for foaming or sloping, Patent Document 7 includes a method of adjusting the viscosity of slag within a prescribed range by adding a viscosity modifier (fluorite, etc.) in a converter, and Patent Document 8 discloses molten iron tapped from a blast furnace. A method of adding a compound of an alkali metal and/or an alkaline earth metal when desiliconizing while receiving is disclosed. By adjusting the viscosity of slag, it is thought that these make it easy to flotation of a breakage and a bubble, and contribute to sedation. However, in order to change the viscosity of the slag, a large amount of sedative (viscosity modifier) is required, and by reducing the viscosity, the movement of substances in the slag is accelerated, the rate of CO gas generation increases, and conversely, there are cases where the foaming increases. There are tasks such as

In addition, any method disclosed in Patent Documents 4 to 8 is a method of adding a sedative to the refining reaction vessel. Bulk molten iron and slag coexist in the refining reaction vessel, and since the agitation is stronger than in the slag receiving vessel, the situation is significantly different from that in the slag receiving vessel. none. For example, since the stirring is strong in the refining reaction vessel, the dispersion of the added sedative agent proceeds quickly, and the sedation rate is fast. On the other hand, since bulk molten iron and slag are stirred in contact with each other, even if it has calmed down once, when the addition of the sedative is stopped, the carbon in the molten iron reacts with the iron oxide in the slag. Throwing it away, things are very different.

Japanese Patent Laid-Open No. 2008-255446 Japanese Patent Laid-Open No. 2009-270178 Japanese Patent Laid-Open No. 2009-287050 Japanese Patent Laid-Open No. 4-1850507 Japanese Patent Laid-Open No. 5-287348 Japanese Patent Laid-Open No. 9-87719 Japanese Patent Laid-Open No. 62-278213 Japanese Patent Laid-Open No. 2003-147425

In view of the problems of the prior art, the present disclosure quickly and stably calms the foaming of discharged slag when discharging slag from a refining reaction vessel such as a converter to a slag accommodating vessel, and prevents slag overflow from the slag accommodating vessel By preventing it, while avoiding troubles, such as equipment damage and an operation disturbance, the fall of productivity accompanying a fall of a slag discharge rate, and deterioration of slag discharge property are prevented, and it aims at realizing slag discharge with high efficiency.

The inventors of the present application earnestly studied a method for rapidly and stably calming the foaming of the discharged slag when discharging slag from a refining reaction vessel such as a converter to a slag accommodating vessel. As a result, by adding a substance having a viscosity reducing effect as a foaming calming agent so as to remain in the upper surface layer of the slag discharged to the slag container, it is possible to quickly calm the foaming, furthermore, to find out the appropriate conditions for carrying out it , completed the present disclosure. The parts made into the summary of this indication are as follows.

(One)

A method of calming the foaming of discharged slag when discharging slag from the refining reaction vessel to the slag receiving vessel,

Adding a substance having a viscosity reducing effect as a foaming sedative to stay in the upper surface of the slag discharged to the slag container

Foaming calming method of discharged slag, characterized in that.

(2)

As a substance having a viscosity reducing effect, an alkali metal compound, an alkaline earth metal compound, or a mixture thereof is used.

The foaming calming method of the discharged slag according to the above (1), characterized in that.

(3)

The addition amount of the substance having the effect of reducing the viscosity is 2 kg or more with respect to 1 t of discharged slag.

The foaming calming method of the discharged slag according to the above (1) or (2), characterized in that.

(4)

The ratio of the material having a viscosity reducing effect having a particle size in the range of 10 mm or less to 70% by mass or more

The foaming and calming method of the discharged slag according to any one of the above (1) to (3), characterized in that.

(5)

The height at which the viscosity reducing material is added is a height of 3 m or less from the top of the slag accommodating container.

The foaming calming method of the discharged slag according to any one of the above (1) to (4), characterized in that.

(6)

The height at which the viscosity reducing substance is added is a height of 60% or less based on the height from the upper end of the slag accommodating vessel of the worktable provided on the side of the refining reaction vessel.

The foaming calming method of the discharged slag according to any one of the above (1) to (4), characterized in that.

(7)

When adding a substance having a viscosity reducing effect, a guide having a sliding slope is used.

The foaming calming method of the discharged slag according to any one of the above (1) to (4), characterized in that.

(8)

When adding a substance having a viscosity reducing effect, a guide having a sliding slope is used,

The height of the lower end of the guide is a height of 3 m or less from the upper end of the slag container

The foaming calming method of the discharged slag according to any one of the above (1) to (4), characterized in that.

(9)

When adding a substance having a viscosity reducing effect, a guide having a sliding slope is used,

The height of the lower end of the guide is 60% or less based on the height from the upper end of the slag accommodating vessel of the worktable provided on the side of the refining reaction vessel.

The foaming calming method of the discharged slag according to any one of the above (1) to (4), characterized in that.

(10)

When adding a substance having a viscosity reducing effect, it is added while avoiding the vicinity of the slag dropping position so that 80% by mass or more of the added viscosity reducing substance is added outside the vicinity of the slag falling position.

The foaming calming method of the discharged slag according to any one of the above (1) to (9), characterized in that.

(11)

When a material having a viscosity reducing effect is added, the viscosity reducing material is injected as a carrier gas in a direction along the upper surface layer portion.

The foaming calming method of the discharged slag according to any one of the above (1) to (4), characterized in that.

(12) a refining facility comprising a refining reaction vessel and a slag receiving vessel for discharging slag from the refining reaction vessel,

Further comprising a guide for adding a foaming sedative to stay in the upper surface layer of the slag discharged to the slag receiving container,

The guide has a sliding slope

Refining equipment, characterized in that.

(13)

The height of the lower end of the guide is 60% or less based on the height from the upper end of the slag accommodating vessel of the worktable provided on the side of the refining reaction vessel.

The refining facility according to (12) above, characterized in that.

According to the present disclosure, at the time of discharging the slag from the refining reaction vessel to the slag accommodating vessel, it becomes possible to quickly and stably calm the foaming of the discharging slag to prevent overflow of the slag from the slag accommodating vessel. In connection with it, while being able to avoid troubles, such as equipment damage and an operation disturbance by overflowing slag, the fall of a slag discharge rate is prevented, and since slag discharge at high speed becomes possible, productivity improves. In addition, since the slag discharge property is also improved, the amount of slag introduced to the dephosphorization or decarburization treatment in the subsequent step is reduced, so that it is possible to reduce the amount of compound phosphorus and auxiliary materials added for preventing sloping and the amount of generated slag.

By the above effect, productivity improvement and cost reduction (reduction of the usage-amount of auxiliary material, reduction of generated slag, suppression of heat loss, improvement of iron content yield) are attained.

1 is a view showing a mechanism in which foaming is calmed by adding a substance having a viscosity reducing effect to remain in the upper surface layer of slag.
It is an example of embodiment of this indication, and is a figure which shows the calming method of foaming at the time of discharging slag from a converter to a slag discharge ladle, and a refining facility.
3 is a table showing conditions and results of Examples and Comparative Examples of the present disclosure.

[A mechanism to calm the foaming]

First, using FIG. 1, in the present disclosure, a substance having a viscosity reducing effect (hereinafter referred to as a "viscosity reducing substance") is added so as to stay in the upper surface surface layer of the slag discharged to the slag container. Describe the instrument used.

As shown in FIG. 1, the foamed slag becomes an aggregate|assembly (foam layer 2) of the bubble 1 with a high gaseous-phase fraction. In the foam layer 2, since the liquid film between the bubbles 1 is discharged and thinned, foaming and foaming calming proceeds. slows down Then, in order to improve a foaming calming rate, it becomes effective to reduce the viscosity of slag, but in order to reduce the viscosity of the whole slag, it is necessary to add a large amount of viscosity reducing substances.

According to the method of the present disclosure, when the viscosity reducing material 5 is added to stay in the upper surface layer of the foamed slag, as shown in FIG. 1, a local extremely low viscosity region 6 with a high concentration of the viscosity reducing material ) is created. Then, in the region 6, the liquid film discharge of the slag (refer to the arrow 4) is accelerated, and the breaking proceeds rapidly. Subsequently, the slag of the discharged liquid film is mixed with the liquid film of the bubbles immediately below it, but since the gaseous phase fraction is high (liquid phase fraction is low), the viscosity reducing material is hardly diluted, and the ultra-low viscosity region 6 is maintained going downhill In this way, by sequentially descending the ultra-low-viscosity region 6 from the upper layer side of the formed slag, chained and rapid seeding proceeds. That is, even if a small amount of the viscosity reducing material is added, a sufficient foaming soothing effect is obtained.

Conversely, when the viscosity reducing material is added to unfoamed bulk slag (bulk slag layer 3), since the viscosity reducing material is diluted, the ultra-low viscosity region cannot be maintained, and the effect is almost ineffective with a small amount of addition. none. In addition, even when added to the inside of the foamed slag (foam layer 2), an extremely low-viscosity region is generated, but since the soothing effect does not act upward, it is more effective than when added so as to remain in the upper surface layer portion. is limited. That is, in adding the viscosity reducing substance, it becomes important to prevent the viscosity reducing substance from infiltrating into the non-forming bulk slag or forming slag, and to be added so as to remain in the upper surface layer portion.

[Reason suitable for foaming calming in the slag container]

Further, from the difference in the forming situation in the refining reaction vessel such as a converter and the slag accommodating vessel such as a slag discharging ladle, the reason why the method of the present disclosure is suitable for foaming calming in the slag accommodating vessel is explained.

First, as compared to in the refining reaction vessel, the agitation in the slag receiving vessel is weak. In the case of the refining reaction vessel, since the stirring is strong, even if the viscosity reducing substance is added to stay in the upper surface layer of the slag, the viscosity reducing substance is diluted by stirring or infiltrated into the forming slag, so it is difficult to exert the effect. On the other hand, in the case of the slag containing container, since the agitation is weak, it is relatively easy to cause the viscosity reducing substance to remain in the upper surface layer of the slag if the method of adding the viscosity reducing substance is appropriately adjusted.

Next, while a large amount of molten iron in bulk exists in the refining reaction vessel, only granular iron mixed in the slag exists in the slag accommodating vessel, and molten iron in bulk does not exist. In the case of a refining reaction vessel, since bulk molten iron and slag are in contact, even if foaming has calmed down once, foaming occurs again by CO gas generated by reacting carbon in molten iron with iron oxide in slag. Therefore, in order to prevent the occurrence of foaming, it is necessary to reduce the viscosity of the entire slag to a region where foaming does not occur, and a large amount of a viscosity reducing substance is required. On the other hand, in the slag accommodating container, once the foaming subsides, foaming does not occur again, so it is effective only by adding a small amount of a viscosity reducing substance so as to remain in the upper surface layer of the slag.

[Embodiment]

Based on the mechanism described above, an embodiment of the present disclosure will be described with reference to FIG. 2 . As shown in FIG. 2, the converter 7 is used as a refining reaction container, and the slag discharge ladle 8 used when slag is discharged|emitted from the converter 7 as a slag accommodation container is taken as an example.

(viscosity reducing substance)

First, as the viscosity reducing substance 12 used as a sedative, it is preferable to use an alkali metal compound, an alkaline earth metal compound, or a mixture thereof.

Although the slag which is easy to form contains a lot _of acidic oxides, such as SiO2, in molten slag, the acidic oxide forms a network structure and has an effect|action which increases a viscosity. On the other hand, it is because the compound of an alkali metal or the compound of an alkaline-earth metal has an effect|action which cut|disconnects a network structure, and reduces a viscosity.

Specific examples of the alkali metal compound and the alkaline earth metal compound include CaF ₂ , CaCO ₃ , CaO, Ca(OH) ₂ , Na ₂ CO ₃ , K ₂ CO ₃ , and the like.

In addition, since the viscosity reducing substance 12 used as a sedative agent is a fluoride or oxide of an alkali metal or alkaline-earth metal, since it does not generate|occur|produce gas at high temperature, it is more preferable from a viewpoint of calming foaming. Among the above embodiments, CaF ₂ , CaO corresponds to this.

In addition, if the viscosity reducing substance 12 used as a sedative is a carbonate or hydroxide of an alkali metal or an alkaline earth metal, it will generate|occur|produce gas at high temperature. Among the embodiments, CaCO ₃ , Ca(OH) ₂ , Na ₂ CO ₃ , and K ₂ CO ₃ correspond to them.

Hereinafter, the detail is demonstrated about the addition method of the viscosity reducing substance used as a sedative agent, addition amount, and conditions of a property.

First, with respect to the method of adding the viscosity reducing substance, it is important to reduce the velocity in the vertical direction at the time when the viscosity reducing substance reaches the slag upper surface surface part in order to remain in the slag upper surface surface layer part.

(height to add viscosity reducing material)

To that end, it is preferable to add the viscosity reducing substance from a lower position. Specifically, the height at which the viscosity reducing material is added is preferably 3 m or less from the top of the slag discharge ladle, and more preferably 2 m or less.

In addition, on the side of the converter, the work table 14 is normally present, and the height of the work table 14 (upper surface) is about 5 m from the upper end of the slag discharge ladle. The height at which the viscosity reducing substance is added may be set based on the work table 14, and the height of the work table 14 from the top of the slag discharge ladle is 100%, and the height of 60% or less (from the top of the slag discharge ladle) height) is preferable, and more preferably 40% or less.

(equipment used for addition)

As the equipment used for the addition, a guide having a sliding slope such as a gutter or a pipe (ie, a member having a function of sliding an object, a chute) may be used. Add by natural fall through the guide. When the viscosity reducing substance slides on the sliding slope, the speed in the vertical direction of the viscosity reducing substance at the lower end of the guide (the height at which the viscosity reducing substance is added) can be reduced. From the viewpoint of reducing the velocity in the vertical direction of the viscosity reducing material, the angle of the guide at the lower end of the guide (that is, the angle defining the velocity direction of the viscosity reducing material at the lower end of the guide, and the angle with respect to the horizontal direction) is , 30° or less is preferable.

The guide 11 of this embodiment is demonstrated in detail using FIG. The guide 11 of this embodiment is provided below the work table 14, and the lower end and upper end of the guide 11 are both located below the work table 14. In addition, the inclination of the guide 11 (average inclination of the inclined surface on which the viscosity reducing substance slides) is less than 45 degrees with respect to the horizontal direction, specifically, it is less than 30 degrees. The height of the lower end of the guide 11 (the height at which the viscosity reducing material is added) is within 3 m from the upper end of the slag discharge ladle 8 , and specifically is set within 2 m. In addition, when the work table 14 is taken as a reference, the height of the lower end of the guide 11 is 60% or less with the height from the upper end of the slag discharge ladle of the work table 14 (5 m in this example) being 100%. and specifically set to 40% or less.

In addition, in order to be uniformly added to the slag upper surface surface layer portion, the guide may be movable or swiveling, a plurality of guides may be used, or the granular or granular material of the viscosity reducing material may be conveyed with a carrier gas and sprayed onto the upper surface surface layer portion.

The method of spraying the upper surface layer part with a carrier gas is a method of spraying the viscosity reducing substance in a direction along the upper surface surface layer part (a direction close to the horizontal direction) using a hose or the like. According to this method, it is easy to reduce the velocity in the vertical direction when the viscosity reducing substance reaches the slag upper surface part, and the viscosity reducing substance can be effectively retained in the slag upper surface surface part.

(Relationship with the vicinity of the slag falling position)

Moreover, in the slag accommodating container, in the vicinity of the slag fall position, stirring is becoming strong locally by the potential energy of a slag fall. Therefore, when the viscosity reducing substance is added in the vicinity of the slag falling position, it is difficult to make the viscosity reducing substance added in the vicinity of the slag falling position remain in the slag upper layer surface portion.

Therefore, it is preferable to avoid and add the slag drop position vicinity. However, it is not intended to exclude that some of the added viscosity reducing substances are added to the vicinity of the slag falling position. That is, it is preferable that 80 mass % or more of the viscosity reducing substance added is added other than the slag fall position by avoiding the slag fall position vicinity and adding, More preferably, it is 95 mass % or more.

Here, the slag drop position vicinity is the inside of the virtual circle on the slag upper layer surface centering on the center of the part where the slag upper layer surface in a slag accommodating container and a slag falling flow collide. Since the diameter of the virtual circle fluctuates with the potential energy of slag fall, it cannot be defined uniformly, but the distance from the lower end of the furnace hole of the tilted converter (refer to Fig. 2) to the upper end of the slag discharge ladle is 5 to 10 m equipment If , the target is in the range of 1 to 2 m.

Further, as the timing of adding the viscosity reducing substance, for example, the slag plane height at which the viscosity reducing substance is added to the slag accommodating container and the slag plane height at which it stops are prescribed as targets in advance, and the slag plane in the slag accommodating container is monitored. What is necessary is just to repeat the addition of a viscosity reducing substance intermittently and intermittently, when a slag surface has reached|attained each prescribed height while doing this.

(addition amount)

Next, as the addition amount of the viscosity reducing substance, it was found that, with respect to 1 t of discharged slag, a sufficient calming effect could not be obtained when the amount was less than 2 kg, and it was found that it was preferable to set it as 2 kg or more.

In addition, the optimum addition amount in the above range varies depending on the capacity of the slag container, slag composition, temperature, the condition of foaming, etc., but it is preferable to investigate an appropriate amount of addition in the general operating condition range by prior testing. .

(Appearance: particle size)

In addition, with respect to the particle size of the viscosity reducing material, if the particle size is large, the viscosity reducing material does not stay in the upper surface layer of the forming slag and is easily infiltrated, furthermore, it takes time to melt, and the formation of an extremely low viscosity region is difficult. There is the problem of delay. Therefore, as a result of examination, although it is in the range of 10 mm or less, the sedative effect is high, and it is not necessary that all particle sizes are in the above range. was found to be obtained. In addition, the lower limit of the particle size is not particularly set, but if the particle size is too small, scattering to the outside of the slag container due to an updraft or gas generated from the slag in the slag container increases. it is preferable

In addition, the particle size is defined as the mesh of a sieve that can pass through particles, and if the particle size is 10 mm or less, it is made to pass through a sieve of 10 mm.

As mentioned above, with respect to embodiment of this indication, a slag discharge ladle used when discharging slag from a converter as a slag accommodating vessel and a converter as a refining reaction container was assumed and demonstrated. However, the subject of the present disclosure is not limited to these vessels, and when discharging slag from another refining reaction vessel (eg, topido car) to another slag receiving vessel (eg, slag discharge pit, etc.), Application of the present disclosure is possible.

In addition, when the entire amount of the sedative agent required cannot be added by the method of the present disclosure due to facility or operational restrictions, a part of the sedative is added by the method of the present disclosure, and the rest of the sedative is added in the same manner as in the prior art, A corresponding effect is obtained.

In addition, although the specific guide 11 has been described above with reference to FIG. 2 , the guide of the present disclosure is not limited thereto. For example, the upper end of the guide may be located above the work table, or a guide whose angle is changed stepwise or continuously with a refracted pipe or the like.

Example

Hereinafter, Examples (hereinafter simply referred to as 'Examples') and Comparative Examples of the present disclosure will be described.

In addition, the conditions of an Example are an example of the conditions employ|adopted in order to confirm the practicability and effect of this indication, and this indication is not limited to this example. Various conditions can be employ|adopted without deviating from the summary of this indication, as long as the objective of this indication is achieved.

(Common conditions)

The test was conducted during slag discharge after dephosphorization treatment in a 350t scale top-bottom odor converter. In addition, the conditions were set to such a degree that the influence on the evaluation due to the change of conditions was generally negligible, and the amount of slag in the furnace after the dephosphorization treatment was about 20 tons.

(Non-Common Conditions)

When discharging slag by tilting the converter after dephosphorization treatment, the method of adding the sedative (including the addition conditions and the position of addition), the residence of the sedative in the upper surface of the slag, the type, amount, and particle size of the sedative are changed, the slag discharge, The slag discharge time and the final tilting angle of the converter were evaluated.

Here, the slag discharge amount was actually measured with a weighing machine installed on the slag discharge ladle bogie. In addition, the slag discharge completion|finish was made into the earlier of the time point when the slag discharge time reached 3.0 min (the longest time that can take slag discharge) from time restriction, or the time when molten iron started flowing out from the furnace. The final tilting angle of the converter is the tilting angle at the end of slag discharge when the vertical state of the converter is 0°. Under the common conditions of Examples and Comparative Examples, when the tilting angle is around 83°, the residual volume in the furnace and the volume of molten iron become almost equal, and the molten iron begins to flow out of the furnace, so that the final tilting angle is almost the upper limit of 83° . In this case, slag discharge is completed at the point when molten iron starts to flow out from the furnace (tilting angle 83°).

(Non-Common Conditions and Results)

The conditions and results of each level are shown in the table of FIG. 3 .

Here, as the conditions for adding the sedative, "a method of storing the sedative in a plastic bag in units of 10 kg at 5 m above the top of the slag discharging ladle" and "2 m above the top of the slag discharging ladle, granular through a pipe" How to add" is compared. Compared to the latter, the former is easier to infiltrate into the slag formed by the sedative.

Moreover, as an addition position of a sedative agent, "the vicinity of a slag fall position" and "outside the vicinity of a slag fall position" are compared. Similarly, the former is more likely to infiltrate the inside of the slag formed by the sedative, compared to the latter.

In addition, about the retention of the sedative agent in the slag upper surface surface layer part, it judged visually. "None" refers to a situation in which instantaneous mixing in the slag, and "Presence" refers to a situation in which it stays on the slag upper surface for a short time (about several seconds). In addition, when adding "outside the slag drop position vicinity" by "a method of adding granularly through a pipe at 2 m above the upper end of the slag discharge ladle", except for cases where visual determination is difficult, in the upper surface of the slag Retention of the sedative was confirmed by visual inspection.

As an evaluation index for foaming calming, it is important to quickly calm foaming with a small amount of sedative and discharge a large amount of slag in a short time. did.

First, levels 1 to 4 are comparative examples, and at least one of the sedative addition method or the sedative type differs from the method of the present disclosure.

In addition, the reason that level 1 is superior to level 2 is that "a molded product of pulp residues and slag" used as a sedative is infiltrated into the slag formed in the first place to rapidly generate gas and calm down. It is thought that

In addition, in Levels 3 and 4, although a viscosity reducing substance was used as a sedative, retention of the sedative in the upper surface of the slag was not confirmed. In addition, compared with levels 1 and 2, in levels 3 and 4, although the same or more effective effect is obtained with a small amount of the sedative, it is not suitable in terms of the cost of the sedative.

Next, levels 5 to 12 are examples, and a high foaming sedative effect was confirmed at any level compared to the comparative example.

In level 5, the addition method of the sedative agent was changed to the method of the present disclosure with respect to the level 4 which is a comparative example, but the amount of the sedative agent added was greatly reduced while obtaining an equivalent average slag discharge rate.

Level 6 changed the type of sedative (viscosity reducing substance) with respect to level 5, but the effect was almost equal to that of level 5.

Levels 7-9 are changing the addition amount (sedative agent addition amount basic unit) of a sedative (viscosity reducing substance) with respect to level 5. By setting the addition amount of the viscosity reducing substance to 2 kg or more with respect to 1 t of the discharged slag, the average slag discharge rate was improved. On the other hand, as can be seen from the results of level 9, there was a region where the effect was saturated even when the amount of the sedative added was increased.

Levels 10 to 12 are changing the particle size (ratio of particle size of 10 mm or less) of the sedative agent (viscosity reducing substance) with respect to level 8. The average slag discharge rate improved by making the ratio of what exists in the range of 10 mm or less of the particle size of a viscosity reducing substance into 70 mass % or more. On the other hand, as can be seen from the results of level 12, there was a region where the effect was saturated even when the ratio of the particle size of 10 mm or less was increased.

As mentioned above, in the Example of this indication, the addition amount of a sedative agent and the average slag discharge rate were superior compared with the comparative example. Therefore, it can be seen that in Examples of the present disclosure, foaming soothing is better than in Comparative Examples. In addition, it can be seen that by setting the amount and particle size of the sedative agent to appropriate conditions, foaming and soothing can be performed more efficiently.

1: Bubble
2: Foam layer
3: bulk slag layer
4: liquid film discharge
5: Viscosity reducing substances (foaming sedatives)
6: Extremely low viscosity region
7: Converter (refining reaction vessel)
8: slag discharge ladle (slag receiving vessel)
9: molten iron
10: slag
11: Guide
12: Viscosity reducing substance (foaming sedative)
13: extremely low viscosity region
14: workbench

Claims (13)

A method of calming the foaming of discharged slag when discharging slag from the refining reaction vessel to the slag receiving vessel,
A substance having a viscosity reducing effect as a foaming sedative is added to stay in the upper surface layer of the slag discharged to the slag container,
By adding avoiding the vicinity of the slag dropping position, 80% by mass or more of the viscosity reducing substance to be added is added outside the slag dropping position
Foaming calming method of discharged slag, characterized in that. According to claim 1,
As a substance having a viscosity reducing effect, an alkali metal compound, an alkaline earth metal compound, or a mixture thereof is used.
Foaming calming method of discharged slag, characterized in that. 3. The method of claim 1 or 2,
The addition amount of the substance having the effect of reducing the viscosity is 2 kg or more with respect to 1 t of discharged slag.
Foaming calming method of discharged slag, characterized in that. 3. The method of claim 1 or 2,
The ratio of the material having a viscosity reducing effect having a particle size in the range of 10 mm or less to 70% by mass or more
Foaming calming method of discharged slag, characterized in that. 3. The method of claim 1 or 2,
The height at which the viscosity reducing material is added is a height of 3 m or less from the top of the slag accommodating container.
Foaming calming method of discharged slag, characterized in that. 3. The method of claim 1 or 2,
The height at which the viscosity reducing substance is added is a height of 60% or less based on the height from the upper end of the slag accommodating vessel of the worktable provided on the side of the refining reaction vessel.
Characterized in that, the foaming calming method of the discharged slag. 3. The method of claim 1 or 2,
When adding a substance having a viscosity reducing effect, a guide having a sliding slope is used.
Foaming calming method of discharged slag, characterized in that. 3. The method of claim 1 or 2,
When adding a substance having a viscosity reducing effect, a guide having a sliding slope is used,
The height of the lower end of the guide is a height of 3 m or less from the upper end of the slag container
Foaming calming method of discharged slag, characterized in that. 3. The method of claim 1 or 2,
When adding a substance having a viscosity reducing effect, a guide having a sliding slope is used,
The height of the lower end of the guide is 60% or less based on the height from the upper end of the slag accommodating vessel of the worktable provided on the side of the refining reaction vessel.
Foaming calming method of discharged slag, characterized in that. 3. The method of claim 1 or 2,
When a material having a viscosity reducing effect is added, the viscosity reducing material is injected as a carrier gas in a direction along the upper surface layer portion.
Foaming calming method of discharged slag, characterized in that. delete A refining facility comprising a refining reaction vessel and a slag receiving vessel for discharging slag from the refining reaction vessel,
Further comprising a guide for adding a foaming sedative to stay in the upper surface layer of the slag discharged to the slag receiving container,
The guide has a sliding slope,
The guide is arranged so that the discharge position of the foaming sedative discharged from the lower end of the sliding slope avoids the vicinity of the slag falling position,
The height of the lower end of the guide is 60% or less based on the height from the upper end of the slag accommodating vessel of the worktable provided on the side of the refining reaction vessel. delete

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