TWI439551B - Inhibition method of converter - Google Patents

Description

Method for suppressing overflow of steelmaking in converter

The invention relates to a converter steelmaking method, in particular to a method for suppressing the overflow of steelmaking in a converter.

The existing converter steelmaking method is to feed the sorghum molten iron produced by the blast furnace into the converter, and to precipitate the impurities in the molten iron by blowing oxygen and slagging, but when oxygen is blown, the oxygen is poured into the molten iron. It will cause the molten iron to churn and overflow outside the converter.

In order to improve the above disadvantages, another prior art converter steelmaking method 1 as shown in FIG. 1 is proposed, which includes a pretreatment step 11 and a steelmaking step 12. In the pretreatment step 11, the molten iron produced by the blast furnace is first subjected to a helium reduction treatment, and then the molten iron having a reduced volume after the helium reduction is sent to the converter for the steelmaking step 12. However, the pretreatment step 11 causes a decrease in the temperature of the high temperature molten iron produced by the blast furnace, so that the molten iron is heated again after being sent to the converter to cause energy loss.

Therefore, how to improve the above-mentioned shortcomings has been an important goal of continuous efforts by those skilled in the art.

Accordingly, it is an object of the present invention to provide a method of suppressing the overflow of steelmaking in a converter outside the converter.

Therefore, the method for suppressing the overflow of the converter steelmaking according to the present invention comprises a preliminary slag step, a pre-slag slag step, and a slagging step.

The preliminary slag step is to feed a gas and a slagging agent into a converter containing a molten iron, and react the impurities in the molten iron with the gas and the slag forming agent to form a floating surface of the molten iron. The slag is adjusted so that the slag has a base degree of 1.0 to 1.4, and the temperature of the molten iron is 1350 ° C to 1450 ° C.

The pre-slag discharging step is to discharge a part of the slag formed by the preliminary slag forming step outside the converter.

The slagging step is to feed the gas into the molten iron after the pre-slag discharging step at a flow rate higher than the preliminary slag forming step.

The effect of the invention is that the method for suppressing the overflow of the converter steelmaking according to the invention is to maintain a good fluidity of the slag by using a low-salt base slagging method to match the appropriate temperature to avoid the occurrence of a floating phenomenon, the pre-slag Step further discharging a part of the slag formed by the initial slag forming step outside the converter, thereby reducing the volume of the slag in the converter, so that a high-flow gas can be sent into the molten iron in the slagging step. The slag floating on the surface of the molten iron is prevented from overflowing outside the converter.

The above and other technical contents, features and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments.

Referring to FIG. 2 and FIG. 3, a preferred embodiment of the method for suppressing the overflow of steelmaking in a converter according to the present invention comprises a preliminary slag step 2, a pre-slag slag step 3, and a slagging step 4.

The preliminary slag step 2 is to feed a gas 24 and a slagging agent 25 into a converter 21 containing a molten iron 22, and react the impurities in the molten iron 22 with the gas 24 and the slag forming agent 25. A slag 23 floating on the surface of the molten iron 22 is formed. In the preferred embodiment, the gas 24 is oxygen (O ₂ ); the slagging agent 25 is lime (calcium oxide CaO); and the molten iron 22 is sorghum hot metal 22 produced by the blast furnace. Specifically, the so-called sorghum hot metal 22 of the preferred embodiment refers to molten iron 22 having a cerium content of more than 1.0%.

In particular, in general, the main impurities contained in the molten iron 22 are usually carbon (C), cerium (Si), manganese (Mn), phosphorus (P), sulfur (S), etc., and the introduction of oxygen is mainly In order to oxidize the impurities, the lime can react with cerium oxide (SiO ₂ ) and form slag 23 . Therefore, in the preferred embodiment, the primary purpose of the preliminary slag step 2 is to dislocate, so this stage may also be referred to as the dislocation period, and a slag 23 having a higher amount of strontium may be formed. In addition, in the preferred embodiment, the oxygen is fed by the top blowing method, and the inert gas is fed by the bottom blowing method, and the inert gas fed by the bottom blowing method can assist the stirring of the molten iron 22 to facilitate the uniformity of oxygen. It reacts with impurities in the molten iron 22.

The pre-slag discharging step 3 is to discharge a part of the slag 23 formed in the preliminary slag step 2 to the outside of the converter 21. In the preferred embodiment, 30% by weight to 50% by weight of the slag 23 is discharged from the outside of the converter 21, based on 100% by weight of the total slag 23. In actual operation, the slag 23 floating on the surface of the molten iron 22 is poured out from the top opening of the converter 21, so that it is difficult to discharge all the slag 23, and discharging 30% to 50% by weight of the slag 23 can significantly reduce the subsequent slag. Floating phenomenon.

This slagging step 4 feeds the gas 24 into the molten iron 22 after the pre-slag slag step 3 at a flow rate higher than the slag forming step 2. In particular, in the preferred embodiment, the primary purpose of the slagging step 4 is to decarburize and other impurities, so this stage may also be referred to as a decarburization period, which results in a higher carbon content. Slag 23

Referring to Table 1, an experimental example and a comparative example of a method for suppressing the overflow of steelmaking in a converter according to the present invention are shown.

It can be seen from Table 1 that in the preliminary slag step 2, the salt base degree of the slag 23 is preferably between 1.0 and 1.4, because when the base degree of the salt is more than 1.4, the floating condition is more obvious, and the salt base degree is more obvious. When it is less than 1.0, the slag amount may be too small to affect the steelmaking efficiency. In the preferred embodiment, the temperature of the molten iron 22 is from 1350 ° C to 1450 ° C, because when the temperature is higher than 1450 ° C, the floating phenomenon is more likely to occur. In summary, when the salt base degree is between 1.0 and 1.4 and the temperature of the molten iron 22 is between 1350 ° C and 1450 ° C, the floating phenomenon can be most effectively suppressed. When the above-mentioned salt base degree and temperature range are exceeded, The phenomenon of floating will be more obvious.

Preferably, in the preliminary slag step 2, the oxygen flow rate is 25000 to 35000 Nm ³ /hr, and the inert gas flow rate is 500 to 1000 Nm ³ /hr. In the slagging step 4, the oxygen flow rate is 45,000 to 60000 Nm ³ /hr, and the inert gas flow rate is 300 to 2000 Nm ³ /hr. Of course, the top blowing oxygen flow rate of the slagging step 4 is greater than the top blowing oxygen flow rate of the preliminary slag step 2, and the bottom blowing inert gas flow rate of the secondary slag forming step 4 is smaller than the bottom blowing of the preliminary slag step 2 The inert gas flow can also achieve the same purpose.

It is to be noted that, of course, after the slagging step 4, the slag 23 is separated from the molten iron 22, however, the subsequent operation after the slag forming step 4 is the same as the prior art, which is the present technology. It is well known to those of ordinary skill in the art and therefore will not be described.

In addition, the method for suppressing the overflow of the converter steelmaking according to the present invention can be used in the general converter steelmaking process to obtain the slag 23 having good fluidity, thereby avoiding the occurrence of a floating phenomenon. Of course, the method for suppressing the overflow of steelmaking in the converter of the present invention can also be applied to the molten iron 22 produced in the overhauled or newly built blast furnace, because the amount of strontium 22 produced by the blast furnace after overhaul or new construction is usually high, so It is usually treated in an inverted manner, and the treatment by the suppression method of the present invention can reduce the amount of scrapped steel.

In summary, the method for suppressing the overflow of steelmaking in the converter of the present invention is to maintain a good fluidity of the slag 23 by a slag forming method with a low salt base to maintain a good fluidity to avoid the occurrence of a floating slag. Step 3 further discharges part of the slag 23 formed in the preliminary slag step 2 out of the converter 21, thereby reducing the volume of the slag 23 in the converter 21, so that a high-flow gas can be obtained in the slag forming step 4. The feed of the molten iron 22 into the molten iron 22 prevents the slag 23 floating on the surface of the molten iron 22 from overflowing the outside of the converter 21, so that the object of the present invention can be achieved.

The above is only the preferred embodiment of the present invention, and the scope of the invention is not limited thereto, that is, the simple equivalent changes and modifications made by the scope of the invention and the description of the invention are All remain within the scope of the invention patent.

2. . . Initial slag step

twenty one. . . Converter

twenty two. . . molten iron

twenty three. . . Slag

twenty four. . . gas

25. . . Slag forming agent

3. . . Pre-slag removal step

4. . . Secondary slag step

Figure 1 is a flow chart illustrating a conventional converter steelmaking method;

Figure 2 is a flow chart showing a preferred embodiment of the method for suppressing the overflow of steelmaking in the present invention;

Figure 3 is a schematic diagram of the preferred embodiment.

2. . . Initial slag step

3. . . Pre-slag removal step

4. . . Secondary slag step

Claims (10)

A method for suppressing overflow of steelmaking in a converter comprises: a preliminary slagging step of feeding a gas and a slag forming agent into a converter containing a molten iron to make impurities in the molten iron and the gas and slagging The agent reacts to form a slag floating on the surface of the molten iron, and adjusts the slag to a base degree of 1.0 to 1.4, and the temperature of the molten iron is 1350 ° C to 1450 ° C; a pre-slag step, the preliminary Part of the slag formed by the slag step is discharged outside the converter; and a slagging step is performed to deliver the gas into the molten iron after the pre-slag step at a flow rate higher than the initial slag step. The method for suppressing the overflow of steelmaking in a converter according to the first aspect of the invention, wherein in the pre-slaging step, 30% by weight to 50% by weight of the slag is discharged as 100% by weight of the total slag Outside the converter. The method for suppressing the overflow of steelmaking in a converter according to the first aspect of the patent application, wherein in the preliminary slag step, slag having a high cerium content is formed, and in the slag forming step, carbon is formed A higher amount of slag. The method for suppressing the overflow of steelmaking in a converter according to the first aspect of the patent application, wherein in the preliminary slag step, the gas comprises an oxygen gas, and the slagging agent is lime. According to the method for suppressing the overflow of the steelmaking steel according to the fourth aspect of the patent application, in the preliminary slag step, the oxygen is sent into the molten iron by a top blowing method, and the bottom blowing method is used. An inert gas is fed into the molten iron. The method for suppressing the overflow of steelmaking in a converter according to the fifth aspect of the patent application, wherein in the step of forming the slag, the oxygen is fed into the molten iron by a top blowing method, and the bottom blowing method is used to An inert gas is fed into the molten iron. The method for suppressing the overflow of steelmaking in a converter according to any one of claims 4 to 6, wherein the oxygen flow rate of the top blowing method in the slag forming step is greater than the oxygen of the top blowing method in the preliminary slag step flow. The method for suppressing the overflow of steelmaking steel according to any one of claims 4 to 6, wherein the inert gas flow rate of the bottom blowing method in the slag forming step is smaller than the bottom blowing method in the preliminary slag step Inert gas flow. The method for suppressing the overflow of steelmaking in a converter according to any one of claims 4 to 6, wherein in the preliminary slag step, the oxygen flow rate is 25000 to 35000 Nm ³ /hr, and the inert gas flow rate is 500~ 1000Nm ³ /hr. The method for suppressing the overflow of steelmaking in a converter according to any one of claims 4 to 6, wherein in the step of forming the slag, the oxygen flow rate is 45,000 to 60000 Nm ³ /hr, and the inert gas flow rate is 300~ 2000 Nm ³ /hr.