KR20020052094A - Device for calming down slag boiling and guidance apparatus for the device - Google Patents

Abstract

PURPOSE: A slag boiling tranquilizer is provided which promptly tranquilizes slag boiling generated during tapping of molten metal in an electric furnace into a ladle, and easily jets out CO gas by reacting with constituents contained in slag in a short period of time. CONSTITUTION: In a tranquilizer which is injected into molten metal to remove impurities, the slag boiling tranquilizer comprises compressed coal(20) which is inserted into one end of a sleeve(10) so that the sleeve(10) is not fallen, and in which a penetration hole is formed in a shaft direction of the sleeve, wherein a composition of the compressed coal(20) comprises 20 to 40 wt.% of dolomite, and 60 to 80 wt.% of sand, the sleeve is made of a paper material, and the penetration hole is tapered in the compressed coal.

Description

Device for calming down slag boiling and guidance apparatus for the device}

The present invention relates to a slag boiling sedative that quickly suppresses the slag boiling phenomenon generated when manufacturing a molten stainless steel in an electric furnace.

In general, when manufacturing stainless steel, scrap metal, chromium, nickel, etc. are used as main raw materials, and these main raw materials are divided into primary and secondary, placed in a basket, and then charged into primary and secondary furnaces and melted.

Melting operation in the electric furnace is divided into primary and secondary, and at this time, an arc is generated between the scrap and the electrode through the three-phase electrode rod and melted using the heat.

In addition, the amount of oxygen (O ₂ ) blown into the furnace using oxygen as an auxiliary heat source is about 500-1200 Nm ³ , and the oxygen (O ₂ ) blown into the furnace is C, Si, Cr, Mn, It reacts with Fe to generate heat.

In a stainless steel molten metal melted in the furnace to carry out the tapping operation at the time of the 1560 ℃, the molten metal is C is about 2.0% or higher, Si is 0.15%, Mn is contained 0.5% of it a blow of oxygen (O ₂₎ and the melt C reacts to produce CO gas.

At this time, the CO gas that has not penetrated the slag layer causes slag boiling that causes the slag layer to swell and burst.

When the slag boiling phenomenon occurs, the tapping operation is delayed, and as shown in FIG. 5, since the slag may boil and overflow out of the ladle 30, the slag boiling phenomenon may be thrown into the ladle 30 by throwing the sleeve 10 into the ladle 30. Calmed down. That is, the CO gas is discharged through the through-hole of the sleeve to calm the boiling phenomenon.

In general, in order to check the composition of molten steel during the main operation in the refining furnace work process, three times of component inquiry is performed per charge, and the sample sleeve used at this time is discarded after one use. The waste sleeve thus discarded is used as the sedation sleeve 10 to be introduced into the ladle 30 during the electric tapping operation.

Conventionally, in order to soothe such slag boiling phenomenon, an operator directly injects the sleeve 10 into the ladle 30 from the work deck in the electric furnace factory.

However, the vertically dropped sleeve 10 when injected into the slag layer has a problem that the gas is ejected only at the moment of dropping and immediately lying horizontally on the slag layer, thereby not functioning as a gas outlet.

In addition, the sleeves 10 may float on the surface of the slag layer and may boil out of the ladle 30 together with the slag, thereby causing a problem of delayed tapping.

On the other hand, since the boiling phenomenon is not soothed even when the sleeve 10 is put in, the boiled slag is solidified by falling around the rail of the ladle trolley 32, and eventually, it is impossible to pull in and take out the trolleys and melt the metal in a post process. Cases often fail to transmit.

In addition, in order to remove the slag now solidified around the rail moving the ladle cart 32 to remove the heat after spraying the coolant, the worker must remove the now with a shovel, lever, pickaxe, etc. There is a problem that the fatigue of workers increases and the possibility of a safety disaster exists.

In addition, since the tapping operation must be waited for a long time while removing the solidified now, the temperature of molten steel drops and the heat source is insufficient during post-processing. There is a problem of degradation.

The present invention has been made to solve the problems as described above, the object is to quickly calm the slag boiling phenomenon generated in the process of tapping the molten molten metal in the ladle, the components contained in the slag It is to provide a slag boiling sedative material to react quickly and to facilitate the ejection of CO gas.

1 is a perspective view showing a slag boiling calming material according to the present invention.

2 is a sectional view seen from A-A of the compressed coal of the slag boiling calming material according to the present invention.

3 is a perspective view illustrating a ladle in which a slag boiling sedative is added according to the present invention.

4 is a view illustrating a sleeve feeding method using an injection chute and a loading rack.

5 is a perspective view illustrating a ladle in which a conventional slag boiling sedative is injected.

6 is a graph showing the relationship between the chromium reduction ratio according to the composition ratio of dolomite and sand.

7 is a graph showing the relationship between the boiling phenomenon and the tapping time.

Explanation of symbols on the main parts of the drawings

10 sleeve 12 sleeve insert chute

14: sleeve stockpile 20: compressed carbon

30: ladle 32: ladle cart

40: electric furnace 42: hot water outlet

In order to achieve the object as described above, the present invention, in the sedative material to remove the impurities in the molten metal, is inserted into one end of the sleeve so that the sleeve does not fall and the through hole is formed in the sleeve axial direction It provides a slag boiling sedative comprising compressed coal.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

1 is a perspective view showing a slag boiling calming material according to the present invention, Figure 2 is a cross-sectional view of the compressed coal of the slag boiling calming material according to the present invention from AA, Figure 3 is a slag boiling calming material according to the present invention A perspective view showing the inserted ladle.

The present invention forms a structure in which the compressed carbon 20 is inserted into one end of the sleeve 10.

The compressed coal 20 preferably has a tapered shape so as to be easily inserted into the sleeve 10, and a through-hole is formed in the center so that the sleeve 10 can be moved by the ejection pressure.

The compressed coal 20 is inserted into one end of the sleeve 10, so that the sleeve 10 introduced into the ladle 30 is not easily collapsed and serves as a chimney so that CO gas that cannot penetrate the slag layer can be smoothly discharged. do.

In particular, the compressed carbon 20 is preferably manufactured by mixing dolomite (MgCO ₃ -CaCO ₃ ) and sand (SiO ₂ ) so as to promote the reaction with various compounds remaining in the slag during combustion.

Dolomite (MgCO ₃ -CaCO ₃ ) is separated into MgO, CaO and C at about 900 ℃.

MgO and CaO are basic oxides, which increase the basicity of slag and lower the viscosity, thus making it easier to eject CO gas, and C is the compound of Cr ₂ O ₃ , SiO ₂ , FeO, MnO in the slag Cr, Fe, Mn, etc. It serves to reduce.

Cr ₂ O ₃ + 3C → 2Cr + 3CO

SiO ₂ + 2C → Si + 2CO

FeO + C → Fe + CO

MnO + C → Mn + CO

The sand is composed of 98% SiO ₂ , 1.8% Al ₂ O ₃ , and other 0.2%.

SiO ₂ in the sand lowers the temperature of the slag and solidifies the slag in the liquid state quickly, so it serves to facilitate the ejection of CO gas in the molten metal.

The slag temperature of the stainless steelmaking process is known to be about 1500-1600 ° C., and when the amount of slag is 5-6 ton, the cooling effect is about 20-30 ° C. when 1 ton of sand is added.

Compressed coal 20 of the present invention is preferably 20 to 40% by weight of dolomite (MgCO ₃ -CaCO ₃ ), 60 to 80% by weight of sand (SiO ₂ ), 40% by weight of dolomite (MgCO ₃ -CaCO ₃ ) Most preferred is 60% by weight of sand (SiO ₂ ).

In particular, when the dolomite (MgCO ₃ -CaCO ₃ ) exceeds 40% by weight, not only the amount of slag increases but also the manufacturing cost increases, and when it is less than 20% by weight, the effect of calming the boiling phenomenon is insufficient.

In addition, when the sand (SiO ₂ ) exceeds 80% by weight, the temperature drop of the molten metal occurs excessively, and when it is less than 60% by weight, the amount of slag increases so that the mixing ratio of dolomite (MgCO ₃ -CaCO ₃ ) and sand (SiO ₂ ) is increased. Care must be taken.

On the other hand, in order to smoothly insert the slag boiling sedative material of the present invention configured as described above in the ladle 30, as shown in Figure 4, the sleeve injection chute to the upper end of the ladle 30 to the tapping deck 34 ( 12) can be installed.

In addition, a conveyor 15 may be installed at the rear of the sleeve inlet chute 12 so that the sleeve 10 stacked on the sleeve holder 14 may be transported to an operator, whereby the sleeve 10 is a ladle 30. When it is injected into the) is uniformly and safely through the sleeve feed chute (12).

EXAMPLE

Compressed coal 20 composed of 10 to 40% by weight of dolomite (MgCO ₃ -CaCO ₃ ) and 60 to 90% by weight of sand (SiO ₂ ) was inserted into one end of the sleeve 10 and introduced into the ladle 30.

After this, the duration of the boiling phenomenon, the tapping time and the chromium (Cr) reduction ratio in each case were measured, and the results are shown in Table 1.

Composition and Results Dolomite (% by weight) Sand (% by weight) Boiling phenomenon (minutes) Tapping time (min) Chromium reduction ratio (% by weight) Example 1 10 90 6 9-10 0.08 Example 2 20 80 4 6 ~ 8 0.1 Example 3 30 70 2 5 ~ 6 0.3 Example 4 40 60 0 3 ~ 4 0.5

As shown in Table 1, the duration of the boiling phenomenon and the tapping time have a proportional relationship, and as the weight% of dolomite (MgCO ₃ -CaCO ₃ ) increases, the boiling phenomenon is alleviated, and thus the tapping time is also reduced. You can see that it is shortened.

When the dolomite (MgCO ₃ -CaCO ₃ ) reaches 40% by weight since the boiling phenomenon hardly occurs, it can be seen as the most preferred case.

In addition, the chromium reduction ratio also increases as the weight percent of dolomite (MgCO ₃ -CaCO ₃ ) increases.

Chromium reduction ratio according to the composition ratio of dolomite (MgCO ₃ -CaCO ₃ ) and sand (SiO ₂ ) was measured and the results are shown in FIG.

As shown in Figure 7, it can be seen that as the composition ratio of dolomite increases, the chromium reduction ratio also increases.

Table 2 shows the results of tapping time and boiling phenomena after the compressed carbon 20 was introduced with 40% by weight of dolomite (MgCO ₃ -CaCO ₃ ) and 60% by weight of sand (SiO ₂ ). The relationship is shown.

River times Charge amount (t) Tapping water (t) Tapping temperature (℃) T-T-Time (minutes) Tapping time (min) Boiling phenomenon E17572 93.96 104 1585 77 3.3 Poor generation E17641 94.1 94 1559 75 3.1 Poor generation E17721 93.8 95.5 1609 76 3 Poor generation E17739 94.2 95.6 1567 72 3.6 Poor generation E17847 94.3 95.5 1565 73 3.3 Poor generation E17866 94.3 99 1585 77 3.8 Poor generation E17934 94.1 93.5 1569 78 3.2 Poor generation E17950 94.1 94.5 1557 83 3.3 Poor generation E18129 93.8 96 1560 81 3.6 Poor generation E18130 94.1 92.5 1584 75 3.4 Poor generation E18732 94.95 95.5 1583 71 3.8 Poor generation Average 94.15 95.96 1,575 76.18 3.40 Good

As shown in Table 2, it can be seen that the amount of boiling phenomenon is inadequate and the tapping time is also good, about 3.4 minutes on average.

Table 3 shows the amount of oxygen and Fe-Si injected into the furnace by electric furnace and the slag component and basicity after the sedatives according to the present invention are added according to each steel grade, and measured by a conventional measuring method.

River times Oxygen injection amount (Nm ³ ) Fe-Si injection amount (kg) CaO (wt%) SiO ₂ (wt%) MnO (wt%) Al ₂ O ₃ (wt%) MgO (wt%) Cr ₂ O ₃ (wt%) FeO (wt%) basicity E17572 877 261 35.42 25.03 5.54 7.92 5.78 8.37 4.43 1.68 E17641 978 106 29.07 18.28 9.51 5.8 4.38 9.51 6.54 1.77 E17721 944 98 32.07 20.89 8.73 5.96 5.06 8.19 5.99 0.81 E17739 974 105 32.23 27.51 7.53 6.05 4.93 10.16 3.72 1.66 E17847 921 263 34.41 28.18 7.34 6.43 5.04 11.29 3.21 1.38 E17866 919 476 35.41 29.93 6.99 6.9 5.35 9.16 3.48 1.64 E17934 840 200 33.41 29.82 7.35 6.73 5.76 10.15 4.14 0.67 E17950 907 256 32.41 29.18 7.04 7.13 5.04 11.96 4.35 1.22 E18129 973 453 28.76 28.13 8.08 5.15 5 10.88 3.01 0.8 E18130 848 259 33.46 29.7 7.48 5.97 5.06 13.24 3.13 1.55 E18732 835 209 37.58 30.77 6.84 5.91 4.91 9.6 2.39 1.59 E18778 882 306 33.59 30.88 8.7 5.61 5.23 10.42 3.46 1.43 E18879 965 260 35.38 31.08 7.35 5.71 4.98 8.92 4.43 1.64 E18880 877 152 36.54 28.18 6.45 6.07 4.51 12.6 3.59 1.74 Average 910 243.1 33.55 27.68 7.49 6.23 5.07 10.31 3.99 1.39

8 shows a comparison of the boiling time and the tapping time in the case of using the compressed coal 20 according to the present invention and when using the conventional working method.

Here, the compressed carbon 20 was composed of 40% by weight of dolomite (MgCO ₃ -CaCO ₃ ) and 60% by weight of sand (SiO ₂ ).

As shown in FIG. 8, the boiling phenomenon is 6 to 7 minutes on average and the tapping time is 8 to 9 minutes on average according to the conventional working method. 0-2 minutes, tapping time can be seen to be reduced to 3-4 minutes.

As described above, according to the slag boiling calming material according to the present invention, even after the sleeve is inserted into the ladle, the sleeve into which the compressed carbon is inserted is erected so that the CO gas in the molten steel is ejected in a short time, thereby suppressing the slag boiling phenomenon. have.

In addition, the compressed carbon not only lowers the viscosity of the slag by reacting with the components of the slag, but also promotes solidification of the slag, thereby facilitating the ejection of CO gas.

Claims (4)

A swelling material that is introduced into a molten metal to remove impurities, the slag boiling swelling material comprising compressed carbon which is inserted into one end of the sleeve to prevent the sleeve from falling and the through hole is formed in the sleeve axial direction. The slag boiling calming material of claim 1, wherein the compressed carbon includes 20 to 40% by weight of dolomite and 60 to 80% by weight of sand. The slag boiling calming material of claim 1 or 2, wherein the sleeve is made of a paper material. The slag boiling calming material according to claim 1 or 2, wherein the compressed coal is formed with a tapered through hole.