KR100398393B1 - Apparatus for enhancing reaction efficiency of desulfurization flux of hot metal - Google Patents

Abstract

The present invention relates to a device for improving the reaction efficiency of the flux itself by using the same flux for desulfurization (FLUX), in the case of removing the sulfur components contained in the molten iron, induces the flux and chemical reaction quickly The present invention relates to an apparatus for improving the reaction efficiency of molten iron desulfurization flux which can achieve the desulfurization effect optimally at the same treatment time by making the original desulfurization capacity of the flux itself to the fullest possible.

In the present invention, when the stirrer of the refining device is rotated during the preliminary refining treatment, flux of 0.1 mm to 1.0 mm particle size is blown in the center of the refining reaction vessel to be mixed effectively, and the flux for molten iron desulfurization does not overlap the stirring effect of the flux. In the reaction efficiency improving apparatus of the stirrer, the stirrer has a three-hole structure in which gas inlets are formed at both ends in the width direction, and one gas inlet is arranged at a position of 1 / 4W in the width direction. W is provided to improve the reaction efficiency of the molten iron flux desulfurization flux, characterized in that the length of the width of the stirrer.

Description

Reaction efficiency improving device for molten iron desulfurization flux {APPARATUS FOR ENHANCING REACTION EFFICIENCY OF DESULFURIZATION FLUX OF HOT METAL}

The present invention relates to an apparatus for improving the reaction efficiency of the flux itself by using the same flux for desulfurization (FLUX), more specifically, in the case of removing the sulfur component contained in the molten iron, the flux and chemical reaction The present invention relates to an apparatus for improving the reaction efficiency of a molten iron desulfurization flux which can achieve the desulfurization effect optimally at the same treatment time by maximizing the desulfurization ability of the flux itself.

In general, desulfurization and refining is performed in the molten iron preliminary process, which is a unit process of the steelmaking process, in the steelmaking, steelmaking, and rolling processes of the integrated steelworks for manufacturing steel products. The above-described molten iron preliminary treatment is a general operation for removing silicon, sulfur, and phosphorus contained as impurities in molten iron from the blast furnace. Flux used in such desulfurization refining is required to have good reaction efficiency. . The reason for removing sulfur in this way is that it is difficult to remove sulfur by oxidative refining from molten iron during converter refining, which is the next unit process, and thus sulfur is removed in advance in the previous step.

Conventional molten iron desulfurization method uses a mechanical stirrer or immersed in a molten iron in a TORPEDO LADLE to induce a chemical reaction at the interface between the molten iron and the solid flux to be injected into the upper molten iron in the ladle Powder blowing device is used. The mechanical stirring device is simple in configuration, low in equipment investment cost, and good in maintainability, but has a disadvantage in that a flux reaction utilization efficiency is low because it is used in a molten iron. In the case of the desulfurization treatment in this manner, the most commonly used flux is calcium carbide.

On the other hand, the powder blowing device is complicated in its configuration, high equipment investment costs, poor maintainability, but because of blowing the flux powder into the molten iron has the advantage of high utilization efficiency of the flux reaction. The adoption of the above methods depends on the plant conditions, but the purpose of the desulfurization treatment is to achieve the desired level in the converter by treating it in a given time by the interfacial reaction between the molten iron and the flux in the vessel (open ladle or topedor ladle) containing the molten iron. It is up to the supply of sulfur by lowering it. To this end, it must be premised on the removal of a large amount of sulfur in the molten iron within a given processing time to speed up the reaction.

In order to achieve the desulfurization effectively, the first value is high and the melting of the refractory used in the container is severe, but the flux of the flux itself has excellent desulfurization ability or a low melting point that becomes liquid at the melting temperature (typically 1350 ° C to 1400 ° C). It is the use of flux which can easily deal with desulfurization in a short time by using. However, this produces less slag and lowers the molten iron temperature during processing. Typical examples of this type include sodium carbonate-based and magnesium fluxes, which require special attention because a large amount of fume (FUME) or dust (DUST) is generated during treatment at molten iron temperature.

Secondly, the desulfurization ability of the flux itself is somewhat lower but cheaper flux. This has the advantage that there is little loss of refractories on the other hand, because the melting of the refractory is small, the amount of use must be large, while there is a big disadvantage in temperature drop. And a typical example of this type is quicklime flux. In particular, since the flux has a high melting point and exists in the solid state at the molten iron temperature, the reaction rate is slow and the contribution efficiency of the desulfurization reaction is low.

In particular, this flux greatly affects the desulfurization rate depending on its composition and particle size, which causes a problem of a large amount of slag generation after treatment. In general, however, the latter quicklime flux is used a lot in industry.

To summarize the problems of the above two methods, in the case of using a mechanical (rotary) stirring device, the flux is put on the molten iron and desulfurized, but the desulfurization efficiency decreases due to atmospheric oxidation of the flux during the treatment, and takes a long time. However, there is a limit to the expansion of the reaction system area between the flux and the molten iron, and thus, there is a fundamental problem that the flux itself does not sufficiently exhibit the desulfurization ability within the given refining time. Typically the reaction contribution rate is from 5 to 10%.

On the other hand, in the case of using the powder blowing device, the lance should be deeply immersed from the hot water and the gas is blown in. The bubbles generated at this time should be blown into the molten iron at the same time as the flux. There is a problem that the reaction time is short because the reaction proceeds during the process. In addition, it is impossible to use a flux of low melting point below the molten iron temperature, and it is necessary to inject solid powder flux, and the contribution rate to the desulfurization reaction is usually only 2-5%.

On the other hand, if a known technique for the conventional desulfurization efficiency improving method, there are the following. Registered in the Republic of Korea Utility Model Registration No. 46071 submitted by the inventor in 1990 is an example of improving the desulfurization efficiency by using a stirrer for gas blow-in bottle, and in 1997 Republic of Korea Patent Application No. 70809 is a lance in the chartered vessel in topedo ladle When blowing the powder using, the quicklime-based flux alone has a problem that the powder flux is low as the specific gravity of 2.0-2.5, so that the rate of intrusion in the molten iron is low, and the iron flux having a specific gravity of 7.0 is mixed with the flux for the purpose of improving the flux. This is an example of improving the desulfurization efficiency due to the effect of improving invasiveness. This is a combination of iron carbide with high specific gravity to inject and disperse as many calcium oxide (CaO) particles directly participating in the desulfurization reaction as possible in the molten iron when the conventional quicklime powder flux is blown into the molten iron using a transport gas. .

This results in less sulfur powder remaining in the bubbles generated from the transport gas during blowing of the molten iron, increasing the infiltration dispersion amount, and increasing the interfacial area of the reaction between calcium oxide and sulfur in the molten iron, thereby increasing the desulfurization efficiency. How to improve.

Here, when desulfurization using the same flux, the most important thing for the stable and efficient removal of sulfur in the molten iron through the effective positional arrangement of the gas inlet in the stirrer is the flux and then the flux and The interfacial reaction between the molten irons, as well as the product (CaS) reacted at the interface is rapidly dispersed evenly into the slag layer to create a new interface quickly.

The present invention has been made in view of the above-mentioned conventional problems, and its purpose is to use a stirrer for gas blowing bottle, but between the desulfurization flux and the molten iron is designed to effectively incorporate a pipe that can blow gas into the mechanical stirrer It is an object of the present invention to provide an apparatus for improving the reaction efficiency of molten iron desulfurization flux which increases the reaction area and at the same time enhances the flux mixability and improves the contribution to the desulfurization reaction.

In addition, the present invention simultaneously improves the above problems of the mechanical stirring method and the powder blowing method, and the mechanical stirring method and the gas blowing are simultaneously enabled to utilize the desulfurization ability of the flux to the maximum desulfurization reaction to improve the desulfurization efficiency. It is to provide a device for improving the reaction efficiency of the molten iron desulfurization flux.

1 is a block diagram of a refining apparatus to which the present invention is applied;

2 is a view showing the concept of the reaction during processing in the refining apparatus to which the present invention is applied,

a) is a plan sectional view, b) is a longitudinal sectional view;

3 is a detailed cross-sectional view of the refining apparatus according to the present invention,

a) a two-hole structure, b) a three-hole structure, c) a four-hole structure;

4 is a graph showing the behavior of sulfur content in molten iron according to the treatment time of Comparative Examples and Inventive Examples 1 and 2. FIG.

Explanation of symbols on the main parts of the drawings

1 ..... Refinery 5 ..... Crucible for protection

7 ..... graphite crucible 9 ..... induction coil

11 .... Chartering 12 .... Flux

15 .... rotating shaft 16 .... agitator

18 .... gas supply hole 19 .... gas blowing hole

21 .... Bubble

The present invention to achieve the above object,

When the stirrer of the refining device rotates during the preliminary refining process, a flux of 0.1 mm to 1.0 mm particle size is blown into the central portion of the refining reaction vessel to effectively mix, and the reaction efficiency of the molten iron desulfurization flux which does not overlap the stirring effect of the flux. In the improving apparatus, the stirrer has a three-hole structure in which gas inlets are formed at both ends in the width direction, and one gas inlet is arranged at a position of 1 / 4W in the width direction. By providing an apparatus for improving the reaction efficiency of the molten iron flux desulfurization flux, characterized in that the length of the stirrer.

The present invention is a four-hole structure in which the gas inlet is formed at each end of the stirrer in the width direction, and the gas inlets are arranged at the positions of 3W / 16 and 11W / 16, respectively, in the width direction. By providing a reaction efficiency improving apparatus of the molten iron desulfurization flux, characterized in that made.

Hereinafter, the present invention will be described in more detail with reference to the drawings.

In the present invention, in the efficient desulfurization treatment using the apparatus shown in Figs. 1 and 2, the stirrer 16 and the molten iron 11 and the flux 12 are properly matched to slag sulfur in the molten iron 11. In this case, the flux 12 injected at this time maximizes the mixing property of the flux 12 itself according to the treatment method, and effectively induces the high temperature of the flux 12 layer to interface with the molten iron 11. The reaction proceeds rapidly to maximize the reaction contribution rate of the flux 12 itself.

As shown in FIG. 1, in the refining apparatus 1 to which the present invention is applied, a protective crucible 5 is formed in a body 3 of a predetermined size, and a graphite crucible 7 is formed inside thereof. The molten iron 11 (hot metal) is contained therein. In addition, an induction coil 9 is mounted outside the protective crucible 5 to heat the molten iron 11 in the crucible 7, and an agitator for supplying the flux 12 into the molten iron 11. (16) is located.

The stirrer 16 is equipped with a rotating shaft 15 to the upper side, a gas supply hole 18 is formed therein, a plurality of gases to the lower side of the stirrer 16 to communicate with the gas supply hole 18 The blowing hole 19 is located. Herein, the present invention relates to the improvement of the special position and arrangement of the gas blowing hole 19 in the stirrer 16 used in the refining apparatus 1 as described above.

The present invention has a structure as shown in FIG.

As shown in FIG. 3b), when the stirrer 16 of the refining apparatus is rotated during the preliminary refining treatment, a flux 12 having a particle size of 0.1 mm to 1.0 mm is blown from the central portion of the refining reaction vessel to effectively mix the flux. In the apparatus for improving the reaction efficiency of the molten iron desulfurization flux (12) such that the stirring effect of (12) is not duplicated, the present invention provides that the gas blowing holes 19 of the stirrer 16 are formed at both ends in the width direction, respectively. And a three-hole structure in which one is formed at a position of 1 / 4W in the width direction.

And, as shown in Figure 3c), the gas blowing hole 19 of the stirrer 16 is formed at both ends in the width direction, respectively, the position of 3W / 16 and 11W / 16 in the width direction It is made of a four-hole structure formed at each position.

In the present invention, the same desulfurization flux 12 is added to the flux 12 above the molten iron 11 in the center of the vessel during mechanical agitation. The gas is efficiently injected from the gas supply hole 18 embedded in the 16 to minimize the reaction area loss between the solid flux 12 and the molten iron 11, and the stirrer is maximized by maximizing the mixing of the flux 12 itself. By allowing bubbles 21 to be produced from (16), there is an effect of increasing the reaction surface area between flux 12 and molten iron 11 and increasing the mixing property of flux 12 on molten iron 11.

In particular, since the flux 12 is calcium carbide, the desulfurization ability is excellent, and carbon monoxide is generated by reacting with carbon monoxide generated after the desulfurization reaction and oxygen in the atmosphere, or carbon monoxide is generated when calcium carbide reacts with oxygen in the atmosphere. As a result, the temperature in the flux 12 is increased to naturally induce a feature that acts advantageously to desulfurization.

At this time, calcium carbide and carbon monoxide react with oxygen in the atmosphere to generate carbon monoxide and carbon dioxide, thereby generating heat, thereby increasing the temperature of the flux 12 itself, and thus improving the desulfurization ability to obtain a synergistic effect of the new desulfurization efficiency. It is a feature of. If this is expressed as a chemical reaction is the same as Scheme 1 and 2.

(CaC ₂ ) _{flux (12)} + [S] → (CaS) + 2 [C]

[C] + 1 / 2O ₂ (g) → CO (g) + heat

(CaC ₂ ) _{flux (12)} + O ₂ (g) → (CaO) + 2CO (g) + heat

CO (g) + 1 / 2O ₂ (g) → CO ₂ (g) + heat

In the reaction, desulfurization is advantageous for the reaction at higher temperature, and [X] means dissolved element in the molten iron (11). In particular, calcium oxide (CaO) produced by the reaction of calcium carbide with atmospheric oxygen as shown in [Scheme 3] is very active because it is produced at high temperature. This calcium oxide is somewhat lower than reacting with sulfur in the molten iron 11 rather than participating in direct reaction with calcium carbide, but is relatively easy to react. This is expressed as chemical reaction 5.

(CaO) + [S] + [C] → (CaS) + CO (g)

In order to achieve the above reaction, in the present invention, the position of the gas blowable gas supply hole 18 embedded in the mechanical stirrer 16 is very important. 3 shows an arrangement of the embedded gas supply holes 18 used in the present invention. Comparative Example is a conventional two-hole type in which the conventional stirrer 16 registered in 1990 is intact, and the gas blowing holes 19 are at both ends, and Inventive Example 1 and Inventive Example 2 are structures according to the present invention.

Inventive Example 1 is a three-hole type, in addition to the comparative example, one gas blowing hole 19 is added at the position of W / 4 (W is the length of the width) in the width direction of the stirrer 16, and Inventive Example 2 is compared. When the stirrer 16 rotates in the width direction in the example stirrer 16, it is a 4-hole type provided in the position of 3W / 16 and the position of 11W / 16, respectively, so that the stirring effect of the flux 12 may not overlap.

Inventive Examples 1 and 2 are designed to solve this problem, because the flux 12 in the center portion has a very low contribution rate to the desulfurization reaction when the stirrer 16 is rotated as shown in FIG. 2. . In order to set the position of the gas blowing hole 19, it is taken as an example of invention that only the most excellent desulfurization effect was obtained by carrying out various preliminary experiments by making into 16 equal parts in the width direction of the stirrer 16. As shown in FIG.

As shown in FIG. 2, the result of setting to another position other than Inventive Example 1 and 2 is that when the gas is blown in more than 4 holes in the width direction of the stirrer 16, the bubble 21 generated by gas blowing is carried out. It was confirmed that the mixing efficiency of the flux 12 was excellent, but the interface between the flux 12 and the molten iron 11 was narrowed, thereby reducing the reaction surface area and reducing the desulfurization effect. In addition to the various, if the installation of a number of gas blowing holes 19 is not only difficult to manufacture, but also a lot of cases in which the agitator 16 during the treatment is broken. On the other hand, the conventional two-hole type is disclosed in Utility Model Registration No. 1990-46071 and used as a reference for the comparative example.

The present invention, unlike the conventional mechanical stirrer 16 or the method of blowing the gas at both ends of the stirrer 16 in the desulfurization treatment of the molten iron, the sulfur of the molten iron 11 throughout the entire process from the start of treatment to completion of the treatment It is characterized by maximizing desulfurization efficiency by effectively removing and making it reproducible. Therefore, the present invention is realized through the application of a treatment method suitable for the operation characteristics to achieve this.

In the present invention, in using the same desulfurization flux 12 in the desulfurization treatment, mechanical blowing force is provided simultaneously with gas blowing and derivation of appropriateness of the positional arrangement of the proper gas blowing holes 19 in the agitator 16.

As can be seen in Schemes 1 to 5, in order to effectively induce desulfurization, even if the same calcium carbide (CaC ₂ ) in the flux 12 is used, the contribution rate to the desulfurization reaction depends on the contribution rate of each scheme. On the other hand, in this contribution rate, the reaction interface area is governed by the flux 12 particle size, which is important to select an appropriate particle size. In other words, the interface between the molten iron 11 and the flux 12 is larger as the particle size of the flux 12 becomes larger, and the smaller the contact area becomes. That is, the larger the surface area of the flux 12 itself, the wider the reaction interface area.

The flux 12 used in the present invention was found to have the best particle size of 0.1-1.0 mm. The reason for this is that when the particle size is less than 0.1 mm, the particles are fine and are dispersed by dust by the hot heat flow of the molten iron 11. Therefore, not only the loss of the flux 12 itself is contaminated, but also the pollution of the flux 12 itself. As the surface area becomes too wide, the losses due to atmospheric oxidation are large and the contribution rate of the reaction decreases.

On the other hand, if the particle size of the flux 12 exceeds 1.0 mm, the loss due to atmospheric oxidation of the flux 12 can be reduced, but the surface area that can react with the molten iron 11 decreases, so that the contribution rate to the desulfurization reaction is lowered. There is a problem.

The present invention incorporates a gas blown pipe into the rotary stirrer 16 to blow the gas at the same time as it rotates to uniform the flux 12 distribution on the molten iron 11 and to suppress atmospheric oxidation so that the flux 12 is desulfurized. In a way that can increase the contribution ratio of, the overall schematic is as shown in FIG.

Another characteristic of the present invention is that the flux 12 injected into the upper part of the molten iron 11 is stirred by the rotation of the stirrer 16, and the flux 12 concentrated in the center of the upper part of the molten iron 11 is a floating blowing gas. Since the bubbles 21 escaped from the stirrer 16 directly under the surface of the molten iron 11 by (Ar, N ₂ ) are uniformly dispersed with the rotation of the stirrer 16, the molten iron 11 and the flux 12 contact each other. Increased chances to do In addition, since the partial pressure of oxygen in the upper portion of the molten iron 11 is reduced by the blown out gas from the hot water surface, the oxidation loss of the flux 12 can be reduced. Therefore, the effect of improving the contribution rate in the desulfurization reaction of the used gas blowing stirrer is further increased.

When this is explained in detail, as shown in FIG. 2, the flux 12 thrown in on the molten iron 11 is stirred by the rotary stirrer 16, and the molten iron 11 upper part and the powder flux 12 are stirred at the same time. The injected gas becomes a bubble 21 and moves in a swirling manner to impart a lot of reactor circuits between the molten iron 11 and the flux 12, thereby improving the contribution rate to the desulfurization reaction.

As such, the present invention solves the problem that the unreacted flux 12, in which the conventional flux 12 does not contribute to the desulfurization reaction, remains in the center of the container as shown in FIG. By properly setting the position and arrangement of 19, the reaction efficiency between the flux 12 and the molten iron 11 can be further improved.

(Example)

The schematic diagram of the apparatus used in the embodiment is as shown in Figure 1, Figure 2 is a conceptual diagram showing the overall behavior of the molten iron 11 and the upper flux 12 during the processing of FIG. The experiment used was a high-frequency atmosphere induction melting furnace, in which 30 kg of cold wire was dissolved in the furnace, and 60 g of calcium carbide (CaC ₂ ) flux (12) having a particle size of 0.1-1.0 mm was added to the stirrer (16). Desulfurization was performed for a minute. At this time, the chemical composition of the cold wire used is shown in Table 1 below, and the composition ratio of the particle size of the flux 12 used is shown in Table 2, respectively.

(Unit: weight%) carbon silicon manganese sign brimstone titanium 4.5 0.35 0.35 0.094 0.025 0.063

Particle size (mm) of used flux (12) 0.1-0.3 0.3-0.5 0.5-0.7 0.7-1.0 53% 20% 12% 5%

The detailed internal structure of the stirrer 16 used by the Example is shown in FIG. 3, The stirring of the used flux 12 is performed by this stirrer 16, and the form of the stirrer 16 is as before. Three kinds. The number of experiments was performed three times for each stirrer (16), and the samples of the molten iron (11) were sampled at 5 minute intervals to confirm the change in sulfur content during treatment. From these results, Table 3 summarizes the analytical values for the sulfur content for each treatment time performed three times for each condition of each example and the average value of contribution to the reaction of the used calcium carbide flux 12 at that time.

division Sulfur content during treatment (× 10 ^-3 %) Contribution efficiency (%) to reaction of flux 12 Desulfurization Rate (%) 0 min 5 minutes 10 minutes 15 minutes 20 minutes 5 minutes 10 minutes 15 minutes 20 minutes Comparative example (two balls) 25 11.3 7.0 5.7 5.4 13.7 18.0 19.3 19.6 78.4 Inventive Example 1 (3-hole type) 25 7.0 3.3 3.0 3.0 18.0 21.7 22.0 22.0 88.0 Inventive Example 2 (4-ball) 25 8.0 4.1 3.5 3.5 17.0 20.9 21.5 21.5 86.0

The contribution rate to the reaction of the flux 12 of Table 3 shows the calcium content which the total calcium powder in the injected calcium carbide reacted with the sulfur in the molten iron 11 in 100 fractions. The change in sulfur content over time is shown schematically in FIG. 4. The flux 12 used for each condition is the same calcium carbide. The contribution rate to the reaction of the flux 12 shown in Table 2 was computed by Formula (1) based on Reaction Formula 1 previously, and the desulfurization rate was computed by Formula (2).

% Contribution to reaction = ([wt% S] i-[wt% S] t) x Wm x MCa / (Ms x MT.Ca x 100)

Desulfurization rate (%) = ([wt% S] i-[wt% S] t) x 100 / [wt% S] f

Here, [wt% S] _i is the content of sulfur in the molten iron 11 before treatment, and [wt% S] _t is the content of sulfur in the molten iron 11 at time t. W _m is the molten iron dose (30,000 g), M _Ca is the atomic weight of calcium (40), M _s is the atomic weight of sulfur (32), and W _T.Ca is calcium powder (37.5 g, _charged ) Calculating the basis for the contribution rate of the calcium carbide to the desulfurization reaction in detail, the calcium carbide is equivalent to the calcium in the calcium carbide because it must be assumed that sulfur in the molten iron reacts according to [Scheme 1]. Only the part that will desulfurize.

That is, since the molecular weight of calcium carbide is 64, the double calcium powder is equivalent to 40, so sulfur (atomic weight 32) in the molten iron 11 reacts to produce calcium sulfide (CaS). The contribution rate of sulfur in the desulfurization reaction is calculated by Equation 1.

In Table 2, the comparative example is selected as a representative example because it is a publicly known technique disclosed by the present inventors as shown in (1) of FIG. The gas blowing hole 19 is derived and selected in a ball shape and a four ball shape. As can be seen from the results in Table 2 above, the change in sulfur content in all three cases starts at 0.025% by weight before treatment. In the order of Comparative Example, Inventive Example 1 and Inventive Example 2, the sulfur content during treatment was 0.0113, 0.007, 0.008% by weight in 5 minutes, 0.007, 0.0033, 0.0041% in 10 minutes, 0.0057, in 15 minutes. It was 0.003 and 0.0035 weight%, and it showed as 0.0054, 0.003, and 0.035 weight% in 20 minutes of completion | finish of a process. The desulfurization rate was the best in the case of Inventive Example 1.

Although the same flux 12 was used from this result, in the comparative example, the sulfur content during the treatment was changed from 0.025 → 0.0113 → 0.007 → 0.0057 → 0.0054 wt%, whereas Inventive Example 1 (3-hole) was 0.025 → 0.007 →. It can be seen that desulfurization was completed after 15 minutes as changed to 0.0033 → 0.003 → 0.003% by weight. And Inventive Example 2 (four ball form) was changed to 0.025 → 0.008 → 0.0041 → 0.0035 → 0.0035% by weight, it was also confirmed that desulfurization no longer proceeds after 15 minutes, as in Example 1, Inventive Example 1 and Similar results were obtained. Figure 4 schematically shows the change in sulfur content during the treatment of the above results.

Although the same flux 12 was used from these results, the three-hole type and the four-hole type as shown in FIG. 3 are compared with the case where the gas blowing holes 19 in the agitator 16 are two-hole type at both ends in the width direction. It is possible to confirm that sulfur is more effectively removed from the molten iron 11 by setting an appropriate position and arrangement.

In addition, the sulfur content change during the treatment and the contribution rate of the flux 12 to the desulfurization reaction showed the same tendency, and the results are summarized in the order of Comparative Example, Inventive Example 1 and Inventive Example 2, at 13.7, 18 for 5 minutes. , 17%, 18, 21.7, 20.9% at 10 minutes, 19.3, 22, 21.5% at 15 minutes, and 19.6, 22, 21.5% at 20 minutes. In addition, as in the above sulfur content change, the contribution rate to the desulfurization reaction during the treatment was changed from 13.7 to 18 to 19.3 to 19.6%, and the comparative example was still unreacted in the flux 12 even after 20 minutes of treatment. It can be seen that it remains, and at the same time, the sulfur content of the molten iron 11 after treatment is higher than that of Inventive Examples 1 and 2. On the other hand, Inventive Example 1 (three-hole form) means that the flux 12 completed the contribution to the desulfurization reaction after 15 minutes as it changed from 18 → 21.7 → 22 → 22%.

Inventive Example 2 (four ball form) is changed to 0.025 → 0.008 → 0.0041 → 0.0035 → 0.0035% by weight, which also means that the flux 12 has completed the contribution to the desulfurization reaction after 15 minutes as in Inventive Example 1. The same phenomenon as in Inventive Example 1 was obtained. This phenomenon occurs even when the same flux 12 is used, as compared with the case where the gas blowing holes 19 in the agitator 16 are two-holes at both ends in the width direction, as shown in FIG. By setting the batch, the contribution of the flux 12 to the desulfurization reaction was completed. Compared with the comparative example, sulfur in the molten iron 11 participates in the reaction with the flux 12 quickly by strengthening the mixing property of the flux 12, It is possible to contribute more effectively.

In addition, in Example 2 (four-hole type), the contribution ratio is somewhat lower than that of Inventive Example 1, when the gas blowing holes 19 have a larger agitation effect of the flux 12 due to the gas blown in, but the area of the generated bubble 21 is increased. It can be seen that this increase is due to narrowing the reaction interface area between the flux 12 and the molten iron 11, and on the other hand, the oxidation of the flux 12 by the atmosphere increases, and the contribution rate of the calcium carbide to the direct reaction is increased. It is also believed that this relatively reduced effect is also present.

As mentioned above, it was proved that the contribution rate of the flux 12 to the desulfurization reaction was directly related to the desulfurization rate. Therefore, the desulfurization rate means that the desulfurization rate is improved and the reaction rate is also increased as the contribution rate of the flux 12 to the desulfurization reaction is improved. The obtained desulfurization rate was 78.4% in the comparative example depending on the treatment time, while it was proved that good results were obtained in Inventive Example 1 at 88.0% and Inventive Example 2 at 86.0%.

As described above, in the present invention, in the case of using the same desulfurization flux 12, the gas blowing hole in the stirrer 16 as in the present invention is compared with the desulfurization treatment using the conventional stirrer 16 (comparative example). By additionally setting the positions and arrangements of 19) to three holes and four holes, bubbles 21 generated by efficiently blowing gas near the molten iron / slag interface can be suitably used. Accordingly, the molten iron 11 / flux (by stirring and rotating the molten iron 11) by effectively increasing the reaction efficiency and the mixing of the flux 12 and increasing the stirring filtration reaction area by mechanical stirring and gas blowing. 12) It is possible to maximize the interface reaction rate.

As a result, not only can the sulfur removal rate and the desulfurization efficiency of the molten iron 11 be greatly improved, but also the molten iron 11 having a low sulfur content can be stably supplied to the converter, which is a post-process. It is possible to reduce the raw unit of flux 12 and at the same time reduce the amount of slag generated after treatment.

Claims (2)

When the stirrer 16 of the refining apparatus is rotated during the preliminary refining process, the flux 12 having a particle size of 0.1 mm to 1.0 mm is blown from the central portion of the refining reaction vessel and mixed effectively, and the stirring effect of the flux 12 is not duplicated. In the device for improving the reaction efficiency of the molten iron flux desulfurization flux, The stirrer 16 has a three-hole structure in which gas blowing holes 19 are formed at both ends in the width direction, and one gas blowing hole 19 is arranged at a position of 1 / 4W in the width direction. W is a reaction efficiency improving device for molten iron desulfurization flux, characterized in that the length of the width of the stirrer (16). According to claim 1, The stirrer 16 is a gas blowing hole 19 is formed at both ends in the width direction, respectively, the gas blowing hole (3W / 16 and 11W / 16 in the width direction, respectively) Reaction efficiency improvement apparatus of the molten iron flux desulfurization flux, characterized in that the four-hole structure arranged 19).