KR101010623B1 - Reduction of molten iron processing time and prevention of lance clogging in postmix method - Google Patents

Abstract

According to the present invention, blow-in occurs when blowing low soda ash into the molten iron at a low temperature in addition to the input time and processing time of the feedstock and the low-temperature molten metal by separating the blowing pattern of the dephosphorization treatment and the dephosphorization treatment during the dephosphorization preliminary treatment in the molten iron preliminary treatment step. The present invention relates to a method for shortening the molten iron processing time and preventing the lance clogging in the postmix method, which is improved to prevent the front end clogging phenomenon of the lance. In the method of operation, characterized in that the debinding, dehydration treatment by continuously mixing a predetermined amount of desorbent at the same time in a time when a predetermined amount of dephosphorization agent is blown during the debinding, dehydration treatment operation.

The present invention can prevent clogging of the blowing lance and the blowing line, and can improve the reaction efficiency by increasing the stirring power by increasing the blowing carrier gas flow rate, and ultimately the effect of increasing the dephosphorization, degassing rate and dephosphorization, dehydration treatment It can reduce the number of blown lances and improve the service life, reduce the load of workers and improve productivity.

Description

METHOD FOR MOLTEN IRON PROCESSING TIME REDUCING AND PREVENTION LANCE CLOGGED IN POSTMIX}

1 is a general molten iron preliminary treatment process chart,

Figure 2 is an illustration of a conventional Tallinn, dehydration device,

Figure 3 is a table and graph showing a comparison of the present invention and conventional delineation and dewatering treatment pattern,

Figure 4 is a schematic reaction showing the process of lance clogging phenomenon is solved in accordance with the present invention.

♧ description of the symbols for the main parts of the drawing ♧

1 .... concrete lime 2 .... thalin

3 .... soda ash 5,6 ... blowing line

7 .... Branch lance 9 .... TLC

According to the present invention, blow-in occurs when blowing low soda ash into the molten iron at a low temperature in addition to the input time and processing time of the feedstock and the low-temperature molten metal by separating the blowing pattern of the dephosphorization treatment and the dephosphorization treatment during the dephosphorization preliminary treatment in the molten iron preliminary treatment step. The present invention relates to a method for shortening the molten iron processing time and preventing the lance clogging in an improved post-mix method to prevent the front end blocking of the lance.

In general, the charter preliminary treatment aims to improve the quality, stabilize the production, and improve the process capacity (quality, quantity, and temporal production) by separating the refining function of the steel and at the same time reduce the cost of refining. In particular, in order to reduce the load of converter refining, which has a significant influence on the quality of steel, the removal of desulfurization, de-lining, and deflowing loads from the charter preliminary treatment should be pursued to streamline and simplify operations.

That is, referring to the molten iron preliminary treatment process diagram shown in Figure 1, when there was no dephosphorization function in the hot metal pretreatment station (HMPS), only the degassing treatment in the molten iron phase after leaving the blast furnace, and all processes of desulfurization, dephosphorization, and decarburization are carried out in the converter. As is known, the converter is an oxidation reactor, whereas the dehydration reaction is a reduction reaction, so it is difficult to perform the degassing treatment in the converter.

However, in the case of the dephosphorization treatment in the converter, the biggest factor that impedes the cleanliness of the steel is oxygen in the converter slag, but in order to increase the dephosphorization capacity of the converter, the high oxygenation of the slag is indispensable, and at the same time, it inhibits the cleanliness of the river. do.

For this reason, eliminating the Tallinn load from the converter means that the hazard of converter slag can be significantly reduced.

Moreover, when blowing the molten iron that is not a talgyu treatment and a large amount of SiO ₂ generated by the oxygen, the generation of these SiO ₂ is to lower the slag basicity (CaO / SiO ₂₎ is tteurige also fall Tallinn ability, ride slag Increasing the amount and high oxygen content of slag causes Fe loss, Mn loss, and increases the cost of converter refractory due to the increase of total iron (T.Fe) and the tapping temperature. In addition, the increase in molten steel (melting) temperature by decarburization in the converter is also disadvantageous to metallurgical in the delineation reaction, and therefore, degreasing treatment must be performed before molten iron is removed.

However, the silicon contained in slag in molten iron after desulfurization treatment has a higher affinity with oxygen than phosphorus, and most of it is oxidized (desurized) prior to the dephosphorization reaction, thereby lowering the slag basicity necessary for the subsequent dephosphorization reaction. This greatly impairs the efficiency of the work. Therefore, in order to suppress this effect, it is important to remove slag of low-basicity produced by this reaction through excretion before molten iron desulfurization and delineation during the molten iron preliminary treatment.

However, as shown in Figs. 1 and 2, dephosphorization agents during dephosphorization and deflow treatment operations in HMPS during the process proceeding in the order of blast furnace deregulation → forward exhaust material → HMPS (talin, degassing) → aftertreatment → charter loading to the converter. ) Due to the content of condensed lime (1) and the amount of silicon and phosphorus and the molten iron temperature, the dephosphorization agent (2) is introduced using nitrogen (4) as the carrier gas, which causes a rapid decrease in the molten iron temperature and the dephosphorization agent (2). After the low temperature (1160 ~ 1250 ℃) molten iron 10 and low specific gravity (0.5 ~ 0.7) of the soda ash (3) does not react in the molten iron, soda ash (3) causes clogging of the blow lance (7) As the raw material is stagnant in the blowing lines 5 and 6, it causes an abnormality in the installation in which the entire blowing lines 5 and 6 are blocked from the blowing lances 7 and 6.

This causes a drastic drop in the molten iron temperature due to excessive demand of blowing time during molten iron preliminary treatment. There is a risk of surface solidification of the molten iron (10) in the TLC (9) after degassing. The locomotive rails now fall to the locomotive rails, making it impossible to move.

In addition, since the molten iron temperature is low, the raw material and the molten iron 10 adhere to the inner wall of the TLC 9 to reduce the filling amount, and the molten iron 10 is attached to the TLC 9 inner wall to solidify. Newly supplied to the TLC (9), the hot water surface of the molten iron (10) rises above the expected height, the risk of occurrence of overflow (flow) of the molten iron (10) is blown at the blown and overflowed in the TLC (9) This will exist.

In addition, the TLC (9) and the ladle shorten the life of the problem occurs due to the increase in the rotation rate and the number of times of use, the blockage of the blow lance (7) and blockage of the blown line (5, 6) occurs, the dehydration process is not carried out In addition, the excessive work time of facility abnormalities lowers work efficiency, and continuous operation is not possible, resulting in a dramatic decrease in productivity.

The present invention was created in view of the conventional problems as described above, and the simultaneous input of a certain amount of desorbent before the injection of a certain amount of dephosphorization agent is improved by improving the dephosphorization and degassing pattern during the demixing of the postmix method. By using the dephosphorizer input line and the desorbent input line at the same time, it is possible to speed up the degassing time and increase the specific gravity of the dephosphorizer. Therefore, it is possible to suppress the evaporation of soda ash by promoting the input by the specific gravity difference and mixing the iron oxide and the soda ash. The purpose of the present invention is to provide a method of shortening the molten iron processing time and preventing the lance clogging in the postmix method, which can eliminate the congestion and eliminate the clogging of the blown lance and the blown line.

In the present invention, in order to achieve the above technical problem, in the method of delineation, deflow treatment operation in HMPS after desulfurization slag deregulated in the blast furnace desulfurization slag in the pre-treatment, a certain amount of dephosphorization agent during It is characterized in that it provides a method for shortening the molten iron processing time and preventing a lance clogging in a postmixing method in which a predetermined amount of desorbent is mixed and mixed at the time of blowing at the same time by mixing and debinding.

Hereinafter, with reference to the accompanying drawings will be described in more detail with respect to the configuration and operation of the present invention.

According to the present invention, when denitrification of the columnar denitrification in the blast furnace is removed from the HMPS after deregulation of the slag in the pre-exhaust, the demineralization of the dephosphorization agent is simultaneously applied to the dephosphorization agent before the injection of the dephosphorization agent is completed. It is configured to use the dephosphorizer input line and the desorbent input line at the same time.

For example, as shown in FIG. 3, before dephosphorization is completed when dephosphorization is performed by adding condensed lime (average 2500 to 4000 Kg) and dephosphorization agent (average 5500 to 12000 Kg) and dephosphorization, for example, about 15 times as compared to the prior art. At the time when about 1,200 ~ 1600Kg of dephosphorizing agent is added about 20 minutes, the soda ash, which is a desorbing agent, is set at an input amount of 60 to 80 Kg / min as an example, and the amount of dephosphorizing agent is reduced than before desorbent is input (for example, , 400Kg / min / min to 50 ~ 80Kg / min / min.

In addition, the flow rate of the carrier gas may be increased so that the flow rate after the point at which the desorbent and the dephosphorizer is started to be mixed is mixed (for example, 10 to 12 Nm ³ /) rather than the flow rate before the point at which the desorbent is mixed (eg 6 Nm ³ / min). min) By changing the blowing, it induces a pressure increase by increasing the input flow rate, solves the problem of non-blowing due to this, and also increases the stirring power, thereby solving the problem of clogging of the blowing lance and the blowing line.

At this time, the dephosphorization agent is FeO as known, and the desorbing agent is soda ash (Na ₂ CO ₃ ).

The reaction process at this time is as follows.

The dehydration reaction by soda ash is carried out by the following equation.

Na ₂ CO ₃ + S + 2C = Na ₂ S + 3CO ..... ①

Here, the soda ash is evaporated by the following equations (2) and (3) together with the reaction of equation (1), and further, the evaporated Na becomes spherical to Na ₂ CO ₃ by the reaction of equation (4), condensing and generating dust.

Na ₂ CO ₃ + 2C = 2Na (g) + 3CO ..... ②

Na ₂ O + C = 2Na (g) + CO ..... ③

2Na (g) + CO ₂ + ½O ₂ = Na ₂ CO ₃ ..... ④

That is, the soda ash used in the soda ash dehydration reaction during soda ash desulfurization is only 10% of the soda ash blown.

As described above, it can be seen that in order to reduce the degassing raw material, the efficiency of the degassing reaction should be improved.

To this end, the sulfur distribution ratio between molten slag (= S in slag / S in molten iron) and the basicity is correlated with each other, thereby increasing the basicity to increase the sulfur distribution ratio to improve the efficiency of the deflow reaction.

In other words, by adding soda ash and iron oxide (FeO) together to improve the efficiency of the degassing reaction, it is necessary to suppress the evaporation of Na by the mixed use of soda ash and iron oxide to suppress the evaporation of Na by the equation (5).

Na ₂ CO ₃ + 2C = 2Na (gas) + 3CO ↑ ..... ⑤

Therefore, the introduction of low specific gravity of soda ash is promoted by iron oxide (specific gravity 1.2), and the foam (FOAM) as shown in FIG. 4 in which the soda ash is stagnant in the molten iron is not reacted and blown out of the desorbent so that blowing of sorbent occurs. It is possible to prevent clogging or blockage on the blowing line, and the evaporation of soda ash is also suppressed by mixing.

EMBODIMENT OF THE INVENTION Hereinafter, the Example of this invention is described.

[Example]

Applicants conducted a test based on a monthly average of 400 TLC data from January 2002 to August 2002 and plotted the results, and are shown in Table 1 below. The amount of molten iron per TLC was approximately 250 tons.                     

As a result of the final test, there was almost no blockage of bleeding lance clogging phenomena, which was 0.6% of the average monthly rate, and the amount of soda ash was also reduced by about 650Kg from 1400Kg. Shortened the minute, and the effect of suppressing the temperature drop of 12 ℃ from 133 ℃ to 121 ℃ was observed.

For example, referring to Table 1, in the case of TLC60 (denoted as "T60" in Table 1) out of 10 TLC, the melting temperature of 235TON, the total temperature of 1343 ° C, the min Cao dose of 2400Kg, the dephosphorizer dose of 7500Kg, and the soda ash feed of 800Kg In addition, the treatment time was 38 minutes, which was 14 minutes shorter than the conventional average time. The components were obtained with phosphorus (P): 0.024% and sulfur (S): 0.004% without the occurrence of blown clogging.                     

In addition, in the case of the treatment example of TLC06, the melt temperature was 250 tons, the total temperature of 1375 ° C, the amount of min Cao, the amount of 2000Kg, the amount of dephosphorizer 7800Kg, the amount of soda ash, the amount of soda ash, 750Kg, and the processing time of 41 minutes. Without generation, the component was able to obtain 0.016% of phosphorus (P) and 0.002% of sulfur (S).

As a result, 10 TLCs were tested, and the average treatment time was 40.4 minutes, which resulted in stable components and stable processing results without any blockage of blow lances and blow lines.

As described above, the present invention can prevent clogging of the blowing lance and the blowing line, and can improve the reaction efficiency by increasing the stirring power by increasing the blowing carrier gas flow rate. It will increase the degassing treatment, reduce the number of blown lances, improve the service life, reduce the load of workers and improve productivity.

Claims (4)

In the method of derinsing the desulfurization in the blast furnace in the HMPS after desulfurization slag discharged from the pre-discharge, In the post-mixing method, the molten metal is shortened and the lance clogging in the post-mixing method is characterized in that the debinding agent Na ₂ CO ₃ is continuously mixed with FeO at a time when a certain amount of the dephosphorizing agent FeO is blown in during the debinding and degassing operation. Prevention method. delete The method according to claim 1, FeO amount from the time of the Na ₂ CO ₃ mixture added is Na ₂ CO ₃ the mixture input point method before the speed-processing the molten iron in a post-mix system time, characterized in that to ensure that loss than the FeO amount and lance clogging prevention is. The method according to claim 1 or 3, Flow rate of the carrier gas supplied through the blow line from the time of the Na ₂ CO ₃ mixture In the hot metal in a post-mix system according to characterized in that so that the Na ₂ CO ₃ increase than the carrier gas flow rate at the time before being put mixed How to reduce processing time and prevent lance clogging.

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