KR desulfurization method for reducing molten iron consumption and application thereof

Abstract

The invention discloses a KR desulfurization method for reducing molten iron consumption and application thereof, relates to the technical field of iron and steel smelting, and solves the problems of slow rhythm of molten iron desulfurization and excessive consumption of a desulfurizing agent in the existing iron and steel smelting. The method comprises the following steps: S1, loading molten iron into a container, and controlling the loading amount of the molten iron at a first preset parameter; s2, setting the depth of a stirring head entering the liquid level of the molten iron; s3, starting a stirrer for stirring; s4, a KR desulfurizing agent is taken and introduced into a discharging device, the discharging speed and the rotating speed of a stirring head during discharging are controlled, and the KR desulfurizing agent is introduced into the container at a time through the feeding end of the discharging device; and S5, further increasing the rotating speed of the stirring head after blanking is finished, and ending desulfurization after a certain time. The invention further provides application of the KR desulfurization method in steel alloy smelting. The desulfurization effect is good, the desulfurization efficiency is high, the molten iron consumption is low, and the production cost of enterprises is reduced. The application of the KR desulfurization method has the advantages of wide application range, universality and high superiority.

Description

Technical Field

[0001] The present invention relates to the technical field of steel smelting, and in particular to a KR desulfurization method for reducing molten iron consumption and application thereof Background Art

[0002] In the current blast furnace steel smelting, the iron consumption for steelmaking is 7,600 to 7,700 tons per day (excluding molten iron ingots). With the further release of ironmaking capacity in the next step, the iron consumption for steelmaking needs to be 8,000 tons or more. In addition, the quality of blast furnace molten iron has fluctuated greatly since February, and the average sulfur content of molten iron is close to 0.15%.

[0003] Therefore, the desulfurization capacity of molten iron is very poor and the consumption of desulfurized molten iron is too high, which is a major problem encountered by the company at this stage. Summary of the invention

[0004] The purpose of the present invention is to solve the problems of poor desulfurization capacity of molten iron and excessive consumption of desulfurized molten iron in existing steel smelting. The present invention provides a KR desulfurization method for reducing molten iron consumption and its application, which can increase the desulfurization capacity of molten iron, reduce the consumption of molten iron and reduce production costs.

[0005] In order to achieve the above-mentioned purpose, the present invention specifically adopts the following technical solutions:

[0006] On the one hand, the present invention provides a KR desulfurization method for reducing molten iron consumption, comprising the following steps:

[0007] S1, take molten iron and put it into the container, and control the amount of molten iron to be loaded to the first preset parameter;

[0008] S2, set the depth of the stirring head into the molten iron liquid surface;

[0009] S3, turning on the agitator to stir;

[0010] S4, take KR desulfurizer and introduce it into the feeding device, and control the feeding speed and the speed of the stirring head during feeding, and introduce the KR desulfurizer into the container at one time through the feeding end of the feeding device;

[0011] S5. After the material is unloaded, the speed of the stirring head is further increased. After a certain period of time, the desulfurization is completed.

[0012] Furthermore, in S1, the first preset parameter is 79-81t.

[0013] Furthermore, in S2, the parameter of the insertion depth of the stirring head is that the insertion depth of the stirring head, the distance from the molten iron liquid surface to the upper part of the stirring head blade is 600 mm.

[0014] Furthermore, in S3, after the stirrer is turned on and rotated slowly for 30 seconds, the stirring speed is controlled to reach 60 r / min or above.

[0015] Furthermore, in S4, the KR desulfurizer comprises, by mass percentage, CaO ≥ 80%, S % ≤ 0.150%, and CaF2 % ≥ 6%.

[0016] Furthermore, in S4, the particle size of the KR desulfurizer is 1-1.5 mm.

[0017] Furthermore, in S4, the feeding speed is 330-350 kg / min, and the rotation speed of the stirring head is 60-80 r / min during feeding.

[0018] Furthermore, in S5, the stirring head rotation speed is increased to be ≥80 r / min.

[0019] On the other hand, the present invention also provides the application of the above-mentioned KR desulfurization method for reducing molten iron consumption in steel alloy smelting.

[0020] Compared with the prior art, the advantages of the present invention are:

[0021] 1. The present invention involves a KR desulfurization method for reducing molten iron consumption, which adjusts various parameters of KR desulfurization and improves the desulfurizer used in the desulfurization process, can effectively improve the desulfurization rhythm of high-sulfur molten iron, and effectively reduce the molten iron consumed in desulfurization, thereby reducing the production cost of the enterprise, having a good desulfurization effect and high efficiency, and less molten iron consumption.

[0022] Specifically, the present invention also optimizes the operation and parameters of KR. Controlling the amount of KR desulfurizer added can avoid adding the desulfurizer too early, that is, when the vortex is not formed, the desulfurizer cannot be fully dispersed into the molten iron with the vortex, and part of the desulfurizer sticks to the shaft of the stirring head, generating a "mushroom" phenomenon, which makes the desulfurization effect poor. If it is added too late, it is easy to splash during high-speed stirring, and the utilization rate of the desulfurizer is reduced. Since the particle size of the KR desulfurizer is optimized in the present invention, the particle size is fine, and the one-time feeding amount is controlled to be controlled at 500-600kg. After the desulfurizer is added, the rotation speed is appropriately increased according to the condition of the stirring head. If there is a phenomenon of surface caking or poor melting of the desulfurizer, the height of the stirring head can be increased, and the desulfurizer is dispersed from the upper layer and then the stirring head is lowered to ensure uniform stirring in the bag. In addition, the rotation speed of the stirring head is optimized to achieve a better desulfurization effect.

[0023] 2. The application of the KR desulfurization method for reducing molten iron consumption involved in the present invention has a wide range of applications, universality and high superiority.

[0024] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0025] Therefore, the detailed description of the embodiments of the present invention provided below is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention.

[0026] All other obtained embodiments belong to the protection scope of the present invention. DETAILED DESCRIPTION

[0027] First, the present invention provides a KR desulfurization method for reducing molten iron consumption, comprising the following steps:

[0028] S1, take molten iron and put it into the container, and control the amount of molten iron to be loaded to the first preset parameter;

[0029] S2, set the depth of the stirring head into the molten iron liquid surface;

[0030] S3, turning on the agitator to stir;

[0031] S4, take KR desulfurizer and introduce it into the feeding device, and control the feeding speed and the speed of the stirring head during feeding, and introduce the KR desulfurizer into the container at one time through the feeding end of the feeding device;

[0032] S5. After the material is unloaded, the speed of the stirring head is further increased. After a certain period of time, the desulfurization is completed.

[0033] It can be understood that the present invention can effectively improve the desulfurization rhythm of high-sulfur molten iron and effectively reduce the molten iron consumed in desulfurization by adjusting various parameters of KR desulfurization and improving the desulfurizer used in the desulfurization process, thereby reducing the production cost of the enterprise, achieving good desulfurization effect, high efficiency, and low molten iron consumption.

[0034] The present invention also optimizes the operation and parameters of KR. Controlling the amount of KR desulfurizer added can avoid adding the desulfurizer too early, that is, when the vortex is not formed, the desulfurizer cannot be fully dispersed into the molten iron with the vortex, and part of the desulfurizer sticks to the shaft of the stirring head, generating a "mushroom" phenomenon, which makes the desulfurization effect poor. If added too late, splashing is easy to occur during high-speed stirring, and the utilization rate of the desulfurizer is reduced. Since the particle size of the KR desulfurizer is optimized in the present invention, the particle size is fine, and the one-time feeding amount is controlled to be controlled at 500-600kg. After the desulfurizer is added, the rotation speed is appropriately increased according to the condition of the stirring head. If there is a phenomenon of surface caking or poor melting of the desulfurizer, the height of the stirring head can be increased, and the desulfurizer is stirred from the upper layer and then the stirring head is lowered to ensure uniform stirring in the bag. In addition, the rotation speed of the stirring head is optimized to achieve a better desulfurization effect.

[0035] In some embodiments of the present invention, in S1, the first preset parameter is 79-81 t. Specifically, the net weight before stripping is controlled at 79-81 t, and the net weight before stripping during the shift is 77-81 t or more than 60%.

[0036] In some embodiments of the present invention, in S2, the parameter of the insertion depth of the stirring head is that the insertion depth of the stirring head is 600 mm from the molten iron liquid surface to the upper part of the stirring head blade. If the insertion is too deep, there is no vortex part and the desulfurizer cannot be fully diffused into the molten iron, so that the desulfurization effect is not very good. If the insertion is too shallow, the molten iron splashes seriously and no vortex is generated, so that the desulfurization effect is not very good.

[0037] In some embodiments of the present invention, in S3, after the stirrer is turned on and rotated slowly for 30 seconds, the stirring speed is controlled to reach 60r / min or above. A vortex is formed on the surface of the molten iron, and the desulfurizer is automatically added at one time. If the desulfurizer is added too early, that is, when the vortex is not formed, the desulfurizer cannot be fully dispersed into the molten iron with the vortex, and part of the desulfurizer sticks to the shaft of the stirring head to form a "mushroom", which affects the desulfurization effect. If it is added too late, splashing is easy to occur during high-speed stirring, and the utilization rate of the desulfurizer is reduced.

[0038] In some embodiments of the present invention, in S4, the KR desulfurizer comprises, by mass percentage, CaO ≥ 80%, S % ≤ 0.150%, and CaF2 % ≥ 6%.

[0039] In some embodiments of the present invention, in S4, the particle size of the KR desulfurizer is 1-1.5 mm. It can be understood that the present invention can achieve a better desulfurization effect by optimizing the components and particle size of the KR desulfurizer.

[0040] In some embodiments of the present invention, in S4, the feeding speed is 330-350 kg / min, and the rotation speed of the stirring head during feeding is 60-80 r / min.

[0041] In some embodiments of the present invention, in S5, the stirring head speed is increased to be ≥ 80 r / min, for example, 80-120 r / min.

[0042] In some embodiments of the present invention, in S5, the desulfurization parameters of the KR desulfurization further include: the injection fluidization flow rate ≥ 3.0m 3 / h.

[0043] In some embodiments of the present invention, in S5, the desulfurization parameters of the KR desulfurization include controlling the desulfurization clearance to be 300 mm and above.

[0044] In some embodiments of the present invention, the specific operations in S5 are:

[0045] (1) After the stirrer rotates slowly for 30 seconds, the stirring speed reaches 60r / min or above, a vortex is formed on the surface of the molten iron, and the desulfurizer is automatically added at one time. If the desulfurizer is added too early, that is, when the vortex is not formed, the desulfurizer cannot be fully dispersed into the molten iron with the vortex. Part of the desulfurizer sticks to the shaft of the stirring head, forming a "mushroom", which affects the desulfurization effect. If it is added too late, splashing is easy to occur during high-speed stirring, and the utilization rate of the desulfurizer is reduced. Considering that the current desulfurizer particle size is relatively fine, the material is controlled within 600kg each time. After the desulfurizer is added, the rotation speed is appropriately increased according to the condition of the stirring head. If there is a lump on the surface or the desulfurizer is not well melted, the stirring head can be raised to disperse the desulfurizer from the upper layer and then lowered to ensure uniform stirring in the bag.

[0046] (2) During on-site operation, the stirring effect is judged by observing the sparks and brightness of the molten iron generated when stirring the molten iron: Usually, if the sparks at the tank mouth are strong and the brightness is high, it means that the stirring speed is too fast; if there are no sparks at the tank mouth and the brightness is dim, it means that the stirring speed is too slow.

[0047] (3) The insertion depth of the stirring head must be moderate. If it is inserted too deep, there will be no vortex part and the desulfurizer cannot be fully diffused into the molten iron, and the desulfurization effect is not very good; if it is inserted too shallow, the molten iron will splash severely and no vortex will be generated, and the desulfurization effect is not very good. According to production practice research, the best insertion depth of the stirring head (the distance from the molten iron liquid surface to the upper part of the stirring head blade) is 600mm (reference value).

[0048] In some embodiments of the present invention, after the desulfurization of each furnace is completed, the spray holes of the spray gun and the nodules around the spray holes must be cleaned to ensure uniform and stable discharge of the material from the spray holes.

[0049] On the other hand, the present invention also provides the application of the above-mentioned KR desulfurization method for reducing molten iron consumption in steel alloy smelting. It can be understood that the application of the KR desulfurization method for reducing molten iron consumption involved in the present invention has a wide range of applications, universality and high superiority.

[0050] Example 1

[0051] In a certain smelting, the following KR desulfurization method for reducing molten iron consumption was used, including the following steps:

[0052] S1, take molten iron and put it into the container, and control the amount of molten iron to be loaded to the first preset parameter;

[0053] S2, set the depth of the stirring head into the molten iron liquid surface;

[0054] S3, turning on the agitator to stir;

[0055] S4, take KR desulfurizer and introduce it into the feeding device, and control the feeding speed and the speed of the stirring head during feeding, and introduce the KR desulfurizer into the container at one time through the feeding end of the feeding device;

[0056] S5. After the material is unloaded, the speed of the stirring head is further increased. After a certain period of time, the desulfurization is completed.

[0057] Example 2

[0058] Based on Example 1, the method of adding the desulfurizer is optimized. See the following table:

[0059]

[0060] In addition, in the slagging step, the slagging step is limited.

[0061] 1) Control the distance between the molten iron slag liquid level in the ladle and the ladle opening, about 50mm.

[0062] 2) Pause for 3-5 seconds when scraping slag to the mouth wall to separate slag and iron

[0063] 3) The molten iron in the ladle shall not flow out of the ladle in strands;

[0064] 4) The slag must be scraped cleanly until the molten iron is exposed. The amount of slag removed must be greater than 85% of the total slag, and there must be no fist-sized lumps of slag.

[0065] The above embodiment is only one implementation of the present invention, and its description is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be based on the attached claims.

Claims

1. A KR desulfurization method for reducing molten iron consumption, characterized in that: The following steps are involved: S1, take molten iron and put it into the container, and control the amount of molten iron to be loaded to the first preset parameter; S2, set the depth of the stirring head into the molten iron liquid surface; S3, turning on the agitator to stir; S4, take KR desulfurizer and introduce it into the feeding device, and control the feeding speed and the speed of the stirring head during feeding, and introduce the KR desulfurizer into the container at one time through the feeding end of the feeding device; S5. After the material is unloaded, the speed of the stirring head is further increased. After a certain period of time, the desulfurization is completed.

2. A KR desulfurization method for reducing molten iron consumption according to claim 1, characterized in that: In S1, the first preset parameter is 79-81t.

3. A KR desulfurization method for reducing molten iron consumption according to claim 1, characterized in that: In S2, the parameter of the insertion depth of the stirring head is that the insertion depth of the stirring head, the distance from the molten iron liquid surface to the upper part of the stirring head blade is 600 mm.

4. A KR desulfurization method for reducing molten iron consumption according to claim 1, characterized in that: In S3, after the stirrer is turned on and rotated slowly for 30 seconds, the stirring speed is controlled to reach 60 r / min or above.

5. A KR desulfurization method for reducing molten iron consumption according to claim 1, characterized in that: In the S4, the KR desulfurizer comprises, by mass percentage, CaO ≥ 80%, S % ≤ 0.150%, and CaF2 % ≥ 6%.

6. A KR desulfurization method for reducing molten iron consumption according to claim 5, characterized in that: In S4, the particle size of the KR desulfurizer is 1-1.5 mm.

7. A KR desulfurization method for reducing molten iron consumption according to claim 1, characterized in that: In S4, the feeding speed is 330-350 kg / min, and the rotation speed of the stirring head is 60-80 r / min during feeding.

8. A KR desulfurization method for reducing molten iron consumption according to claim 1, characterized in that: In S5, the stirring head rotation speed is increased to be ≥80 r / min.

9. Application of a KR desulfurization method for reducing molten iron consumption according to any one of claims 1 to 8 in steel alloy smelting.

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