Method for reducing consumption of KR desulfurizer

Abstract

The invention relates to a method for reducing consumption of a KR desulfurizing agent, and the KR desulfurizing process comprises the following steps: 1) pre-removal: after temperature measurement and sampling of molten iron and before sample returning, determining a pre-feeding stirring model according to a feeding stirring model of the desulfurizing agent, adding the desulfurizing agent according to the pre-adding amount and the pre-stirring time, and stirring; (2) supplementing materials, namely supplementing, adding and stirring a desulfurizing agent after the molten iron is returned to the sample; calculating the supplementary adding amount and supplementary stirring time of the desulfurizing agent according to the feeding stirring model of the desulfurizing agent; and (3) strengthening: after material supplementation is finished, continuously stirring for more than 2 minutes at a high speed by the stirring paddle to ensure that the desulfurizing agent and the molten iron are uniformly mixed and fully reacted, and the desulfurization process is finished. According to the method, a three-step desulfurization operation mode of pre-desulfurization, material supplementation and adjustment is adopted, accurate addition of the desulfurizing agent during KR desulfurization is achieved, the phenomenon that the desulfurizing agent is wasted due to the fact that the addition amount is too large when the desulfurizing agent is added according to the predicted sulfur content of the molten iron of the blast furnace is prevented, and therefore consumption of the KR desulfurizing agent is effectively reduced.

Description

Technical Field

[0001] The invention relates to the technical field of molten iron pretreatment, and in particular to a method for reducing the consumption of a KR desulfurizing agent. Background Art

[0002] Generally speaking, sulfur is a harmful element in steel. The presence of sulfur in steel has a great impact on the formability, tensile strength, corrosion resistance, crack resistance and fatigue of steel. With the rapid development of science and technology, higher performance requirements are placed on steel. Improving the purity of molten steel by reducing harmful elements such as P and S in steel is an effective technical means to improve the performance of steel.

[0003] The so-called KR desulfurization method is to immerse the cross-shaped stirring head cast with refractory materials and baked into the molten pool of the molten iron ladle to a certain depth. By virtue of the vortex generated by its rotation, the weighed desulfurizer is added to the surface of the molten iron from the feeder and is drawn into the molten iron by the vortex so that the calcium oxide-based desulfurization powder and the molten iron are fully contacted and reacted to achieve the purpose of desulfurization. Its advantages are excellent kinetic conditions, which are conducive to the use of cheap desulfurizers (such as CaO), relatively stable desulfurization effect, high desulfurization efficiency (S≤0.005%), low desulfurizer consumption, and especially suitable for low-sulfur steel varieties.

[0004] The amount of desulfurizer added is closely related to the desulfurization efficiency. Generally, as the amount of desulfurizer increases, the desulfurization rate of molten iron increases. However, when the amount of desulfurizer increases to a certain amount, the desulfurization rate increases very little, which increases the cost of desulfurization pretreatment and brings more slag, thereby increasing the difficulty of slagging and temperature drop. Therefore, the amount of desulfurizer should be controlled within an appropriate range.

[0005] When the temperature of the molten iron from the blast furnace is low, the molten iron cap will freeze, the molten iron tank edge will be large, and the residual iron tank will frequently appear. At this time, it is necessary to smoothly measure the temperature and take samples before KR desulfurization and after slagging. The normal sampling time takes several minutes. However, during continuous production, there is no such condition. Desulfurization can only be done by adding desulfurizer according to the predicted sulfur content of the molten iron in the blast furnace. At present, the conventional feeding mode of KR desulfurization in China is one-time feeding, that is, all desulfurizers are added to the molten iron at one time. Due to the large deviation between the predicted sulfur content of the molten iron and the actual sulfur content of the molten iron, it is very easy to have the phenomenon that the target sulfur after desulfurization is higher than the requirement or the desulfurizer is wasted due to adding too much desulfurizer. Summary of the invention

[0006] The present invention provides a method for reducing the consumption of KR desulfurizer. The three-step desulfurization operation mode of "pre-desulfurization-feeding-adjustment" is adopted to realize the accurate addition of desulfurizer during KR desulfurization, and prevent the waste of desulfurizer caused by excessive addition when adding desulfurizer according to the predicted sulfur content of molten iron in the blast furnace, thereby effectively reducing the consumption of KR desulfurizer.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] A method for reducing KR desulfurization agent consumption, the KR desulfurization process comprises the following steps:

[0009] 1) Pre-desulfurization: After the molten iron temperature is measured and sampled and before the sample is returned, the pre-feeding and stirring model is determined according to the feeding and stirring model of the desulfurizer, that is, the sulfur content of the molten iron in the blast furnace is used instead of the actual sulfur content of the molten iron detected. On the basis of determining the set addition amount and set stirring time of the corresponding desulfurizer, the pre-feeding amount and pre-stirring time of the desulfurizer are calculated; the pre-feeding amount of the desulfurizer is determined according to 55% to 65% of the set addition amount, and the pre-stirring time is determined according to 45% to 55% of the set stirring time. The desulfurizer is added and stirred according to the pre-feeding amount and the pre-stirring time; during the pre-desulfurization process, the stirring paddle is set to high-speed stirring;

[0010] 2) Feeding: After the molten iron is sampled, the desulfurizer is supplemented and stirred; according to the feeding and stirring model of the desulfurizer, the supplementary addition amount of the desulfurizer and the supplementary stirring time are calculated; the supplementary addition amount of the desulfurizer = the set addition amount - the pre-added amount, the supplementary stirring time = the set stirring time - the pre-stirring time; the desulfurizer is added and stirred according to the supplementary addition amount and the supplementary stirring time of the desulfurizer; after the pre-desulfurization is completed, the stirring paddle is adjusted to medium-speed stirring, and the feeding starts after stirring for 10 seconds; after the supplementary desulfurizer is completely immersed in the molten iron vortex, the stirring paddle is readjusted from medium-speed stirring to high-speed stirring, and the supplementary stirring time starts at this time;

[0011] 3) Strengthening: After the feeding is completed, the stirring paddle continues to stir at high speed for more than 2 minutes to ensure that the desulfurizer and molten iron are evenly mixed and fully reacted, and the desulfurization process is completed.

[0012] Furthermore, in the step 1) and the step 2), the relationship between the adding and stirring model of the desulfurizer, that is, the set adding amount of the desulfurizer and the set stirring time and the actual sulfur content of the molten iron detected is as follows:

[0013] Actual molten iron sulfur content 0.025% ≤ S 实际 When the content of desulfurizer is less than 0.030%, the setting amount of desulfurizer is 14.0-14.2 kg / ton iron, and the setting stirring time is 0.10-0.12 min / ton iron;

[0014] Actual molten iron sulfur content 0.030% ≤ S 实际 When the content of desulfurizer is less than 0.035%, the estimated amount of desulfurizer added is 15.1-15.3 kg / ton iron, and the pre-mixing time is 0.10-0.12 min / ton iron;

[0015] Sulfur content of blast furnace hot metal 0.035% ≤ S 实际When the content of desulfurizer is less than 0.040%, the estimated amount of desulfurizer added is 16.2-16.4 kg / ton iron, and the pre-mixing time is 0.11-0.13 min / ton iron;

[0016] Sulfur content of blast furnace hot metal 0.040% ≤ S 实际 When the content of desulfurizer is less than 0.045%, the estimated amount of desulfurizer added is 17.3-17.5 kg / ton iron, and the pre-mixing time is 0.11-0.13 min / ton iron;

[0017] Sulfur content of blast furnace hot metal 0.045% ≤ S 实际 When the content of desulfurizer is less than 0.050%, the estimated amount of desulfurizer added is 18.4-18.6 kg / ton iron, and the pre-mixing time is 0.12-0.14 min / ton iron;

[0018] Sulfur content of blast furnace hot metal 0.050% ≤ S 实际 When ≤0.055%, the estimated amount of desulfurizer added is 19.5-19.7 kg / ton iron, and the pre-stirring time is 0.12-0.14 min / ton iron.

[0019] Furthermore, in step 1), the relationship between the estimated amount of desulfurizer added and the pre-stirring time and the sulfur content of molten iron in the blast furnace, i.e., the pre-charging model, is as follows:

[0020] Sulfur content of blast furnace hot metal 0.025% ≤ S 高炉 When the content of desulfurizer is less than 0.030%, the estimated amount of desulfurizer added is 7.8-9.2 kg / ton iron, and the pre-mixing time is 0.05-0.06 min / ton iron;

[0021] Sulfur content of blast furnace hot metal 0.030% ≤ S 高炉 When the content of desulfurizer is less than 0.035%, the estimated amount of desulfurizer added is 8.4-9.9 kg / ton iron, and the pre-mixing time is 0.05-0.06 min / ton iron;

[0022] Sulfur content of blast furnace hot metal 0.035% ≤ S 高炉 When the content of desulfurizer is less than 0.040%, the estimated amount of desulfurizer added is 9.0-10.7 kg / ton iron, and the pre-mixing time is 0.05-0.07 min / ton iron;

[0023] Sulfur content of blast furnace hot metal 0.040% ≤ S 高炉 When the content of desulfurizer is less than 0.045%, the estimated amount of desulfurizer added is 9.6-11.3 kg / ton iron, and the pre-mixing time is 0.05-0.07 min / ton iron;

[0024] Sulfur content of blast furnace hot metal 0.045% ≤ S 高炉When the content of desulfurizer is less than 0.050%, the estimated amount of desulfurizer added is 10.2-12.1 kg / ton iron, and the pre-mixing time is 0.06-0.07 min / ton iron;

[0025] Sulfur content of blast furnace hot metal 0.050% ≤ S 高炉 When ≤0.055%, the estimated amount of desulfurizer added is 10.8-12.7 kg / ton iron, and the pre-stirring time is 0.06-0.07 min / ton iron.

[0026] Furthermore, the rotation speed of the stirring paddle during high-speed stirring is 115-120 r / min, and the rotation speed during medium-speed stirring is 60-65 r / min.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] 1) The three-step desulfurization operation mode of "pre-desulfurization-feeding-adjustment" is adopted to achieve accurate addition of desulfurizer during KR desulfurization, preventing the waste of desulfurizer due to excessive addition when adding desulfurizer according to the predicted sulfur content of molten iron in the blast furnace, thereby effectively reducing the consumption of KR desulfurizer.

[0029] 2) The method is simple, easy to operate, and has obvious effects after implementation, which is conducive to reducing production costs. DETAILED DESCRIPTION

[0030] The method for reducing the consumption of KR desulfurizer described in the present invention, the KR desulfurization process comprises the following steps:

[0031] 1) Pre-desulphurization: After the molten iron temperature is measured and sampled and before the sample is returned, the pre-feeding and stirring model is determined according to the desulfurizer feeding and stirring model, that is, the sulfur content of the blast furnace molten iron is used instead of the actual molten iron sulfur content detected, and the pre-feeding amount and pre-stirring time of the desulfurizer are calculated on the basis of determining the set addition amount and set stirring time of the corresponding desulfurizer; the pre-feeding amount of the desulfurizer is determined according to 55% to 65% of the set addition amount, and the pre-stirring time is determined according to 45% to 55% of the set stirring time, and the desulfurizer is added and stirred according to the pre-feeding amount and the pre-stirring time; during the pre-desulphurization process, the stirring paddle is set to high-speed stirring.

[0032] 2) Feeding: After the molten iron is sampled, the desulfurizer is supplemented and stirred; according to the desulfurizer feeding and stirring model, the supplementary addition amount of the desulfurizer and the supplementary stirring time are calculated; the supplementary addition amount of the desulfurizer = the set addition amount - the pre-added amount, the supplementary stirring time = the set stirring time - the pre-stirring time; the desulfurizer is added and stirred according to the supplementary addition amount and the supplementary stirring time of the desulfurizer; after the pre-desulfurization is completed, the stirring paddle is adjusted to medium speed stirring, and the feeding is started after stirring for 10 seconds; during the feeding period, the state of the molten iron surface is paid attention to at any time, and after the supplementary material is completely immersed in the molten iron vortex, the stirring paddle is readjusted to high-speed stirring to prevent spillage and waste during the feeding process; the supplementary stirring time starts after the high-speed stirring is readjusted;

[0033] 3) Strengthening: Since the stirring paddle is adjusted from high speed to medium speed to high speed during the feeding stage, the total desulfurization stirring time needs to be extended by more than 2 minutes than the set stirring time to strengthen the desulfurization effect and avoid uneven mixing of the desulfurizer and molten iron due to insufficient stirring time after feeding, resulting in insufficient reaction, poor desulfurization effect and waste of desulfurizer.

[0034] Furthermore, in the step 1) and the step 2), the relationship between the adding and stirring model of the desulfurizer, that is, the set adding amount of the desulfurizer and the set stirring time and the actual sulfur content of the molten iron detected is as follows:

[0035] Actual molten iron sulfur content 0.025% ≤ S 实际 When the content of desulfurizer is less than 0.030%, the setting amount of desulfurizer is 14.0-14.2 kg / ton iron, and the setting stirring time is 0.10-0.12 min / ton iron;

[0036] Actual molten iron sulfur content 0.030% ≤ S 实际 When the content of desulfurizer is less than 0.035%, the estimated amount of desulfurizer added is 15.1-15.3 kg / ton iron, and the pre-mixing time is 0.10-0.12 min / ton iron;

[0037] Sulfur content of blast furnace hot metal 0.035% ≤ S 实际 When the content of desulfurizer is less than 0.040%, the estimated amount of desulfurizer added is 16.2-16.4 kg / ton iron, and the pre-mixing time is 0.11-0.13 min / ton iron;

[0038] Sulfur content of blast furnace hot metal 0.040% ≤ S 实际 When the content of desulfurizer is less than 0.045%, the estimated amount of desulfurizer added is 17.3-17.5 kg / ton iron, and the pre-mixing time is 0.11-0.13 min / ton iron;

[0039] Sulfur content of blast furnace hot metal 0.045% ≤ S 实际When the content of desulfurizer is less than 0.050%, the estimated amount of desulfurizer added is 18.4-18.6 kg / ton iron, and the pre-mixing time is 0.12-0.14 min / ton iron;

[0040] Sulfur content of blast furnace hot metal 0.050% ≤ S 实际 When ≤0.055%, the estimated amount of desulfurizer added is 19.5-19.7 kg / ton iron, and the pre-stirring time is 0.12-0.14 min / ton iron.

[0041] Furthermore, in step 1), the relationship between the estimated amount of desulfurizer added and the pre-stirring time and the sulfur content of molten iron in the blast furnace, i.e., the pre-charging model, is as follows:

[0042] Sulfur content of blast furnace hot metal 0.025% ≤ S 高炉 When the content of desulfurizer is less than 0.030%, the estimated amount of desulfurizer added is 7.8-9.2 kg / ton iron, and the pre-mixing time is 0.05-0.06 min / ton iron;

[0043] Sulfur content of blast furnace hot metal 0.030% ≤ S 高炉 When the content of desulfurizer is less than 0.035%, the estimated amount of desulfurizer added is 8.4-9.9 kg / ton iron, and the pre-mixing time is 0.05-0.06 min / ton iron;

[0044] Sulfur content of blast furnace hot metal 0.035% ≤ S 高炉 When the content of desulfurizer is less than 0.040%, the estimated amount of desulfurizer added is 9.0-10.7 kg / ton iron, and the pre-mixing time is 0.05-0.07 min / ton iron;

[0045] Sulfur content of blast furnace hot metal 0.040% ≤ S 高炉 When the content of desulfurizer is less than 0.045%, the estimated amount of desulfurizer added is 9.6-11.3 kg / ton iron, and the pre-mixing time is 0.05-0.07 min / ton iron;

[0046] Sulfur content of blast furnace hot metal 0.045% ≤ S 高炉 When the content of desulfurizer is less than 0.050%, the estimated amount of desulfurizer added is 10.2-12.1 kg / ton iron, and the pre-mixing time is 0.06-0.07 min / ton iron;

[0047] Sulfur content of blast furnace hot metal 0.050% ≤ S 高炉 When ≤0.055%, the estimated amount of desulfurizer added is 10.8-12.7 kg / ton iron, and the pre-stirring time is 0.06-0.07 min / ton iron.

[0048] Furthermore, the rotation speed of the stirring paddle during high-speed stirring is 115-120 r / min, and the rotation speed during medium-speed stirring is 60-65 r / min.

[0049] The sulfur contents described in the present invention are all by mass.

[0050] In order to more intuitively embody the present invention, the embodiments of the present invention are further described in conjunction with examples. The following examples are only preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any technical solution that can be obviously obtained by a person skilled in the art within the technical scope disclosed in the present invention, including simple changes or equivalent replacements, is within the protection scope of the present invention.

[0051] [Example]

[0052] After the KR desulfurization system of a production line in a steel plant was renovated, pneumatic sampling replaced the original manual sampling and furnace testing. However, due to the long sample return time, the time from sampling, air cooling to chemical testing is 8 to 10 minutes, and the conditions for equal sampling are not available during continuous production. If desulfurization is carried out according to the predicted sulfur content of molten iron in the blast furnace, the sulfur content of the molten iron after desulfurization will be higher than the furnace entry requirement, or too much desulfurizer will be added, resulting in waste.

[0053] This embodiment adopts the method of reducing desulfurization agent consumption of the present invention to produce silicon steel, and the specific implementation process is as follows:

[0054] 1. Pre-stripping;

[0055] Before the desulfurization sample is collected for chemical testing, the predicted sulfur content of molten iron in the blast furnace is used as a reference, and the pre-addition amount of desulfurizer and the pre-stirring time are determined according to the desulfurizer feeding and stirring model (as shown in Table 1).

[0056] Table 1 Desulfurizer feeding and stirring model

[0057]

[0058]

[0059] Note: During KR desulfurization, the amount of molten iron loaded into the molten iron tank is 92t.

[0060] According to 60% of the addition amount set in Table 1 as the pre-addition amount of the desulfurizer, and according to 50% of the stirring time set in Table 1 as the pre-stirring time, the pre-addition model of the desulfurizer is obtained, as shown in Table 2.

[0061] Table 2 Pre-feed stirring model of desulfurizer

[0062] Blast furnace predicted hot metal S, % Pre-addition amount of desulfurizer, t Pre-mixing time, min 0.025～0.030 0.8 5 0.030～0.035 0.8 5 0.035～0.040 0.9 5.5 0.040～0.045 1.0 5.5 0.045～0.050 1.0 6 0.050～0.055 1.1 6

[0063] 2. Feeding;

[0064] After the chemical inspection of the molten iron sample, first calculate the desulfurizer addition amount and supplementary stirring time for the desulfurizer feeding and stirring model in Table 1. The supplementary addition amount = set addition amount - pre-addition amount, and the supplementary stirring time = set stirring time - pre-stirring time.

[0065] After the pre-desulfurization is completed, the stirring paddle is reduced from high speed (118r / min) to medium speed (62r / min), and the feeding is started after 10s of medium speed stirring. After observing that the added desulfurizer has completely entered the molten iron vortex (10s after feeding), the stirring paddle is readjusted to high speed stirring, and the supplementary stirring time starts from the time when it is readjusted to high speed stirring.

[0066] 3. Adjustment: After the feeding is completed, the stirring paddle continues to stir at high speed for 3 minutes, and the desulfurization process is completed.

[0067] Effect verification: The consumption of desulfurizer before and after implementation is shown in the following table:

[0068] Production year Iron S, % Outbound S, % Desulfurizer addition amount, kg Molten iron volume, t Desulfurization agent consumption, kg / t iron 2023-07 0.039 0.0034 1638 92 17.8 2003-08 0.036 0.0032 1722 92 18.7 2003-09 0.032 0.0039 1291 92 14.0 2003-10 0.035 0.0037 1486 92 16.1

[0069] Conclusion: The implementation effect of the method of the present invention is obvious. From July to August 2023, the conventional method was used for desulfurization (comparative example), and from September to October 2023, the method of the present invention was used for desulfurization (example). The unit consumption of desulfurizer was reduced from 17.8-18.7 kg / t iron to 14-16.1 kg / t iron, reducing the desulfurizer consumption by about 17.5%.

[0070] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for reducing KR desulfurization agent consumption, characterized in that: The KR desulfurization process includes the following steps: 1) Pre-desulfurization: After the molten iron temperature is measured and sampled and before the sample is returned, the pre-feeding and stirring model is determined according to the feeding and stirring model of the desulfurizer, that is, the sulfur content of the molten iron in the blast furnace is used instead of the actual sulfur content of the molten iron detected. On the basis of determining the set addition amount and set stirring time of the corresponding desulfurizer, the pre-feeding amount and pre-stirring time of the desulfurizer are calculated; the pre-feeding amount of the desulfurizer is determined according to 55% to 65% of the set addition amount, and the pre-stirring time is determined according to 45% to 55% of the set stirring time. The desulfurizer is added and stirred according to the pre-feeding amount and the pre-stirring time; during the pre-desulfurization process, the stirring paddle is set to high-speed stirring; 2) Feeding: After the molten iron is sampled, the desulfurizer is supplemented and stirred; according to the feeding and stirring model of the desulfurizer, the supplementary addition amount of the desulfurizer and the supplementary stirring time are calculated; the supplementary addition amount of the desulfurizer = the set addition amount - the pre-added amount, the supplementary stirring time = the set stirring time - the pre-stirring time; the desulfurizer is added and stirred according to the supplementary addition amount and the supplementary stirring time of the desulfurizer; after the pre-desulfurization is completed, the stirring paddle is adjusted to medium-speed stirring, and the feeding starts after stirring for 10 seconds; after the supplementary desulfurizer is completely immersed in the molten iron vortex, the stirring paddle is readjusted from medium-speed stirring to high-speed stirring, and the supplementary stirring time starts at this time; 3) Strengthening: After the feeding is completed, the stirring paddle continues to stir at high speed for more than 2 minutes to ensure that the desulfurizer and molten iron are evenly mixed and fully reacted, and the desulfurization process is completed.

2. A method for reducing KR desulfurization agent consumption according to claim 1, characterized in that: In the step 1) and the step 2), the relationship between the adding and stirring model of the desulfurizing agent, that is, the set adding amount of the desulfurizing agent and the set stirring time and the actual sulfur content of the molten iron detected is as follows: Actual molten iron sulfur content 0.025% ≤ S 实际 When the content of desulfurizer is less than 0.030%, the setting amount of desulfurizer is 14.0-14.2 kg / ton iron, and the setting stirring time is 0.10-0.12 min / ton iron; Actual molten iron sulfur content 0.030% ≤ S 实际 When the content of desulfurizer is less than 0.035%, the estimated amount of desulfurizer added is 15.1-15.3 kg / ton iron, and the pre-mixing time is 0.10-0.12 min / ton iron; Sulfur content of blast furnace hot metal 0.035% ≤ S 实际 When the content of desulfurizer is less than 0.040%, the estimated amount of desulfurizer added is 16.2-16.4 kg / ton iron, and the pre-mixing time is 0.11-0.13 min / ton iron; Sulfur content of blast furnace hot metal 0.040% ≤ S 实际 When the content of desulfurizer is less than 0.045%, the estimated amount of desulfurizer added is 17.3-17.5 kg / ton iron, and the pre-mixing time is 0.11-0.13 min / ton iron; Sulfur content of blast furnace hot metal 0.045% ≤ S 实际 When the content of desulfurizer is less than 0.050%, the estimated amount of desulfurizer added is 18.4-18.6 kg / ton iron, and the pre-mixing time is 0.12-0.14 min / ton iron; Sulfur content of blast furnace hot metal 0.050% ≤ S 实际 When ≤0.055%, the estimated amount of desulfurizer added is 19.5-19.7 kg / ton iron, and the pre-stirring time is 0.12-0.14 min / ton iron.

3. A method for reducing KR desulfurization agent consumption according to claim 1, characterized in that: In the step 1), the relationship between the estimated amount of desulfurizer added and the pre-stirring time and the sulfur content of molten iron in the blast furnace, i.e., the pre-charging model, is as follows: Sulfur content of blast furnace hot metal 0.025% ≤ S 高炉 When the content of desulfurizer is less than 0.030%, the estimated amount of desulfurizer added is 7.8-9.2 kg / ton iron, and the pre-mixing time is 0.05-0.06 min / ton iron; Sulfur content of blast furnace hot metal 0.030% ≤ S 高炉 When the content of desulfurizer is less than 0.035%, the estimated amount of desulfurizer added is 8.4-9.9 kg / ton iron, and the pre-mixing time is 0.05-0.06 min / ton iron; Sulfur content of blast furnace hot metal 0.035% ≤ S 高炉 When the content of desulfurizer is less than 0.040%, the estimated amount of desulfurizer added is 9.0-10.7 kg / ton iron, and the pre-mixing time is 0.05-0.07 min / ton iron; Sulfur content of blast furnace hot metal 0.040% ≤ S 高炉 When the content of desulfurizer is less than 0.045%, the estimated amount of desulfurizer added is 9.6-11.3 kg / ton iron, and the pre-mixing time is 0.05-0.07 min / ton iron; Sulfur content of blast furnace hot metal 0.045% ≤ S 高炉 When the content of desulfurizer is less than 0.050%, the estimated amount of desulfurizer added is 10.2-12.1 kg / ton iron, and the pre-mixing time is 0.06-0.07 min / ton iron; Sulfur content of blast furnace hot metal 0.050% ≤ S 高炉 When ≤0.055%, the estimated amount of desulfurizer added is 10.8-12.7 kg / ton iron, and the pre-stirring time is 0.06-0.07 min / ton iron.

4. A method for reducing KR desulfurization agent consumption according to claim 1, characterized in that: The rotation speed of the stirring paddle during high-speed stirring is 115-120 r / min, and the rotation speed during medium-speed stirring is 60-65 r / min.

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