Slag skimmer for unfreezing solidified molten iron in iron storage type main runner and unfreezing method

Abstract

The invention provides a skimmer for unfreezing solidified molten iron in an iron storage type main runner and an unfreezing method.The skimmer comprises two connectors, a replacement cross beam, a small well and an iron runner, the two connectors are oppositely arranged on the two side walls of the main runner, the two ends of the replacement cross beam are connected with the two connectors respectively, and the replacement cross beam is connected with the small well. A distance exists between the replacement cross beam and the upper surface of the solidified molten iron below the replacement cross beam, the width of the replacement cross beam is smaller than that of the connector, the small well is arranged on one side of the replacement cross beam, and the small well is close to one end of the main channel. The small well is communicated with the main channel on the other side of the replacement cross beam through a space below the replacement cross beam, the iron channel is arranged at one end of the main channel, and the iron channel is communicated with the small well. By means of the skimmer, solidified molten iron in the main runner can be rapidly melted, and the normal iron storage and skimming functions of the main runner are recovered.

Description

Technical Field

[0001] The invention relates to the technical field of metallurgical engineering, and in particular to a slag skimmer and a thawing method for thawing solidified molten iron in an iron storage type main groove. Background Art

[0002] At present, the blast furnace ironmaking process is equipped with an iron storage main ditch. This main ditch combines the two traditional process devices, the main ditch and the slag skimmer, into one whole, which makes the slag and iron separation effect better, prolongs the service life, is simpler to operate and maintain, and greatly reduces the labor intensity of workers. However, when the blast furnace is dealing with special furnace conditions such as furnace cooling, furnace freezing, pipeline travel, furnace opening and shutdown, the molten iron temperature is often very low. At this time, if the work in front of the furnace is not in place, it is easy to cause the molten iron in the iron storage main ditch to solidify at a temperature lower than the melting point due to heat loss, so that it completely loses the function of iron passing and slag skimming. In the event of such an accident, it can only be completely dismantled by mechanical destructive means and then remade. Not only does it consume a lot of manpower and material resources, but the construction time is long, which seriously affects the normal production of the blast furnace.

[0003] The main groove in the prior art has the following disadvantages:

[0004] 1. When the main trench loses its iron-passing and slag-skimming function, it is necessary to use large-scale mechanized equipment such as excavators and blasting, as well as violent destruction and demolition methods. Not only is the construction process complicated, but it is also highly destructive. It is easy to cause damage to large concrete building structures such as the iron-casting yard where the iron-storage main trench is located, as well as important equipment and facilities near the iron-storage main trench;

[0005] 2. Industrial pure oxygen cutting is required, which may cause safety hazards and environmental pollution;

[0006] 3. Long construction time. It usually takes more than 15 to 20 days to completely dismantle and rebuild the iron storage main trench, which causes the iron mouth where the iron storage main trench is located to be unable to be put into production for a long time, causing a significant impact on blast furnace production;

[0007] 4. The solidified molten iron in the main trench of the iron storage type becomes scrap iron, and its recycling requires crushing and disintegration and other processes for further processing, which is costly and causes great losses. Summary of the invention

[0008] The object of the present invention is to provide a slag skimmer and a thawing method for thawing solidified molten iron in an iron storage type main groove. The slag skimmer can be used to quickly melt the solidified molten iron in the main groove and restore the normal iron storage and slag skimming functions of the main groove.

[0009] In order to achieve the above object, the present invention provides the following technical solutions:

[0010] A slag skimmer for thawing solidified molten iron in an iron storage type main groove, the slag skimmer is arranged at one end of the main groove, the molten iron is solidified in both the main groove and the slag skimmer, the slag skimmer comprises a joint, a replacement beam, a small well and an iron groove, wherein two joints are arranged oppositely on the two side walls of the main groove, the two ends of the replacement beam are connected to the two joints respectively, there is a distance between the replacement beam and the upper surface of the solidified molten iron below the replacement beam, the width of the replacement beam is smaller than the width of the joint, the small well is arranged on one side of the replacement beam, the small well is close to one end of the main groove, the small well is connected to the main groove on the other side of the replacement beam through the space below the replacement beam, and the iron groove is arranged at one end of the main groove, and the iron groove is connected to the small well.

[0011] Furthermore, in the above-mentioned slag skimmer for thawing solidified molten iron in the iron storage type main groove, the width of the replacement beam is 60% of the width of the joint, and the axis of the replacement beam is colinear with the axis of the joint.

[0012] Furthermore, in the above-mentioned slag skimmer for thawing solidified molten iron in the iron storage type main groove, the upper surface of the joint, the upper surface of the replacement beam and the upper surface of the main groove are all located in the same plane, and the height of the replacement beam is 0.3m.

[0013] Furthermore, in the above-mentioned slag skimmer for thawing solidified molten iron in the iron storage type main groove, the length of the joint is 0.1m.

[0014] Furthermore, in the above-mentioned slag skimmer for thawing solidified molten iron in the iron storage type main groove, the distance between the lower surface of the replacement beam and the upper surface of the solidified molten iron below the replacement beam is greater than or equal to 0.3 m.

[0015] On the other hand, a method for thawing solidified molten iron in an iron storage type main groove is provided, which is implemented by using the above-mentioned slag skimmer for thawing solidified molten iron in an iron storage type main groove, and the thawing method comprises the following steps:

[0016] Step 1, dismantling the existing beam: dismantling the existing beam on the slag skimmer in the main ditch, and retaining 0.1m of refractory material at both ends in the length direction of the existing beam as the joint for casting the replacement beam;

[0017] Step 2, casting a replacement beam: casting the replacement beam at the location of the existing beam using a mold, wherein the size of the replacement beam is smaller than the size of the existing beam;

[0018] Step 3, injecting high-temperature molten iron smelted in the blast furnace into the main trench, using the high-temperature molten iron to melt the solidified molten iron in the main trench, and restoring the normal iron storage and slag skimming functions of the main trench.

[0019] Furthermore, in the above-mentioned thawing method, in step 1, all refractory materials in the depth direction of the existing beam are removed until solidified molten iron can be seen in the depth direction; when the rigidity strength of the refractory material is relatively high and it is impossible to remove all of it, it must be removed at least to a height of 0.6m below the upper surface of the existing beam.

[0020] Furthermore, in the above-mentioned thawing method, in the step 2, the replacement beam after casting is baked, and the baking time is greater than or equal to 6 hours.

[0021] Furthermore, in the above-mentioned thawing method, in the step 3, the temperature of the high-temperature molten iron used to melt the solidified molten iron is greater than 1450°C.

[0022] Furthermore, in the above-mentioned thawing method, in the step 2, the replacement beam is casted by a mold using a main ditch castable material, and the mold is made of a steel plate, and the thickness of the steel plate used to make the mold is 1 to 3 mm.

[0023] It can be seen from the analysis that the present invention discloses a slag skimmer and a thawing method for thawing solidified molten iron in an iron storage type main ditch. The overall implementation of the slag skimmer is simple and the manufacturing cost is low. When removing the existing crossbeam of the slag skimmer, it can be done by using an ordinary handheld small pneumatic pick or a trenching machine that has been configured on site, without the need to call other large-scale mechanical equipment such as excavators from outside the site. Since there is no intervention of large-scale mechanical equipment or devices, no mechanical destructive construction methods are used, so there is no destructiveness to large concrete building structures such as blast furnace iron-making yards. The manpower and material resources required for construction are very small and the cost is low. There is no need to use industrial pure oxygen to burn solidified molten iron, avoiding the safety hazards and environmental pollution caused by melting molten iron with industrial pure oxygen. The thawing method is not only convenient, fast, safe and environmentally friendly, but also has a short thawing time, saving time and labor and small losses. It is achieved that the solidified molten iron in the main ditch and the slag skimmer is fully recovered, melted again into ordinary steelmaking molten iron and used, reducing the economic losses caused by ironmaking accidents. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. Among them:

[0025] Figure 1 It is a structural schematic diagram of an iron storage type main ditch in the prior art.

[0026] Figure 2 It is a structural schematic diagram of an embodiment of the present invention.

[0027] Explanation of the reference numerals: 1 main ditch; 2 slag skimmer; 3 existing crossbeam; 4 small well; 5 solidified molten iron; 6 replacement crossbeam; 7 joint; 8 iron inlet; 9 iron outlet; 10 iron ditch. DETAILED DESCRIPTION

[0028] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments. Each example is provided by way of explanation of the present invention and does not limit the present invention. In fact, it will be clear to those skilled in the art that modifications and variations may be made in the present invention without departing from the scope or spirit of the present invention. For example, a feature shown or described as a part of one embodiment may be used in another embodiment to produce yet another embodiment. Therefore, it is desired that the present invention encompasses such modifications and variations within the scope of the appended claims and their equivalents.

[0029] In the description of the present invention, the terms "longitudinal", "lateral", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and do not require that the present invention must be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention. The terms "connected", "connected" and "set" used in the present invention should be understood in a broad sense. For example, it can be a fixed connection or a detachable connection; it can be a direct connection or an indirect connection through an intermediate component; it can be a wired electrical connection, a radio connection, or a wireless communication signal connection. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0030] One or more examples of the present invention are shown in the accompanying drawings. The detailed description uses numbers and letter labels to refer to features in the drawings. Like or similar labels in the drawings and description have been used to refer to like or similar parts of the present invention. As used herein, the terms "first", "second", "third", etc. are used interchangeably to distinguish one component from another and are not intended to indicate the location or importance of individual components.

[0031] like Figure 1 to Figure 2As shown, according to an embodiment of the present invention, a slag skimmer for thawing solidified molten iron in an iron storage type main groove is provided, the slag skimmer 2 is arranged at one end of the main groove 1, the molten iron is solidified in both the main groove 1 and the slag skimmer 2, the slag skimmer 2 comprises a joint 7, a replacement beam 6, a small well 4 and an iron groove 10, wherein two joints 7 are provided, the two joints 7 are relatively arranged on the two side walls of the main groove 1, the two ends of the replacement beam 6 are respectively connected to the two joints 7, there is a distance between the replacement beam 6 and the upper surface of the solidified molten iron 5 below the replacement beam 6, the width of the replacement beam 6 is smaller than the width of the joint 7, the small well 4 is provided on one side of the replacement beam 6, the small well 4 is close to one end of the main groove 1 relative to the replacement beam 6, the small well 4 is connected to the main groove 1 on the other side of the replacement beam 6 through the space below the replacement beam 6, the iron groove 10 is provided at one end of the main groove 1, and the iron groove 10 is connected to the small well 4.

[0032] Further, the width of the replacement beam 6 is 60% of the width of the joint 7, and the axis of the replacement beam 6 is colinear with the axis of the joint 7, that is, the width of the replacement beam 6 is reduced by 40% relative to the width of the joint 7, so that the two sides of the replacement beam 6 form an iron inlet 8 and an iron outlet 9 for the flow of high-temperature molten iron. Such a setting enables the high-temperature molten iron to flow from the iron inlet 8 into the space below the replacement beam 6 and flow out from the iron outlet 9, so that the high-temperature molten iron can be used to melt the solidified molten iron 5 in the main groove 1 and the slag skimmer 2. The upper surface of the joint 7, the upper surface of the replacement beam 6 and the upper surface of the main groove 1 are all located in the same plane, and the height of the replacement beam 6 is 0.3m. The length of the joint 7 is 0.1m. The distance between the lower surface of the replacement beam 6 and the upper surface of the solidified molten iron 5 below the replacement beam 6 is greater than or equal to 0.3m.

[0033] like Figure 1 As shown, the iron storage type main ditch 1 in the prior art is provided with an existing crossbeam 3. When the blast furnace is in a cold state, the furnace cylinder is frozen, the pipe travels, and the furnace is opened or shut down, the molten iron temperature is often very low. At this time, if the furnace front work is not in place, the main ditch 1, the slag skimmer 2, and all the spaces on the left and right sides and the depth direction of the existing crossbeam 3 on the slag skimmer 2 below the horizontal plane of the iron ditch 10 will be filled with solidified molten iron 5. Since there is no space, the molten iron smelted in the blast furnace will not be able to pass through the main ditch 1 for iron passing and slag skimming. The main ditch 1 also completely loses its function, resulting in the inability of the blast furnace iron mouth where the iron storage type main ditch 1 is located to produce.

[0034] like Figure 2 As shown, a portion of the existing beam 3 is removed, and then a replacement beam 6 is cast in the pit where the existing beam 3 is removed. The width, height and length of the replacement beam 6 are all smaller than the existing beam 3, so that the space on both sides and below the replacement beam 6 forms a channel for the flow of high-temperature molten iron.

[0035] For example, the existing crossbeam 3 of the iron storage type main channel 1 in the prior art has a length of 1.0m, a width of 0.8m, and a height of 0.7m. The width of the replacement crossbeam 6 is 0.48m (60% of the width of the existing crossbeam 3). The space of 20% of the width of the existing crossbeam 3 on one side of the replacement crossbeam 6 is used as the iron inlet 8 of the high-temperature molten iron, and the space of 20% of the width of the existing crossbeam 3 on the other side of the replacement crossbeam 6 is used as the iron outlet 9 of the high-temperature molten iron. The length of the replacement crossbeam 6 is 0.8m, and the two ends of the existing crossbeam 3 retain a length of 0.1m as the joint 7 for casting the replacement crossbeam 6. In the depth direction, all the refractory materials of the existing beam 3 are removed until the solidified molten iron 5 is seen. If the rigidity of the refractory materials is high and it is impossible to remove all of them, in the height direction of the existing beam 3, it is necessary to remove it at least to a height of 0.6m below the upper surface of the existing beam 3. The height of the cast replacement beam 6 is 0.3m, so that there is a space of greater than or equal to 0.3m below the cast replacement beam 6 for the passage of high-temperature molten iron.

[0036] When the temperature of the molten iron smelted in the blast furnace rises to above 1450°C, the main groove 1 of the replacement beam 6 that has been manufactured and baked can be used. The high-temperature molten iron above 1450°C flows in the main groove 1 with the solidified molten iron 5, passes through the iron inlet 8 of the skimmer 2, passes through the bottom of the replacement beam 6, and then rises in the iron outlet 9 of the skimmer 2 and overflows the small well 4, and flows into the iron groove 10. Under the action of the melting of the molten iron temperature above 1450°C, the solidified molten iron 5 will be melted and flow away, restoring the normal iron storage and slag skimming functions of the main groove 1.

[0037] The present invention also discloses a method for thawing solidified molten iron in an iron storage type main groove, which is implemented by using the above-mentioned slag skimmer for thawing solidified molten iron in an iron storage type main groove. The thawing method comprises the following steps:

[0038] Step 1, dismantling the existing beam 3: Use a pneumatic pick, trenching machine and other equipment to dismantle the existing beam 3 on the slag skimmer 2 in the main trench 1, and retain 0.1m of refractory material at both ends in the length direction of the existing beam 3 as joints 7 for casting the replacement beam 6; all refractory materials in the height direction of the existing beam 3 are dismantled until solidified molten iron 5 can be seen in the depth direction; when the rigidity strength of the refractory material is high and it is impossible to dismantle it all, it must be dismantled at least to a height of 0.6m below the upper surface of the existing beam 3.

[0039] Step 2, casting the replacement beam 6: Use a mold to cast the replacement beam 6 at the position of the existing beam 3, and use the main ditch castable material to cast the replacement beam 6 through the mold. The mold is made of steel plate, and the thickness of the steel plate used to make the mold is 1 to 3 mm (for example: 1mm, 2mm, 3mm). The size of the replacement beam 6 is smaller than the size of the existing beam 3; the replacement beam 6 after casting is baked, and the baking time is greater than or equal to 6h. After the existing beam 3 is removed, install the mold. The mold is made of a steel plate with a thickness of 1 to 3mm according to the size of the replacement beam 6 and installed in the pit after the removal of the existing beam 3. After the mold is installed, use the main ditch castable material to cast the replacement beam 6. After the replacement beam 6 is cast, it is baked. After the replacement beam 6 is dried, the replacement beam 6 is completed, and the replacement beam 6 is connected to the skimmer 2 of the main ditch 1 through the joint 7. The casting material of the main ditch 1 is used to cast the replacement cross beam 6 through a mold. Since the amount of casting material is small, the main ditch 1 can be put into use after the baking time of the replacement cross beam 6 is met for 6 hours.

[0040] Step 3, inject the high-temperature molten iron smelted in the blast furnace into the main groove 1, and use the high-temperature molten iron to melt the solidified molten iron 5 in the main groove 1 and the slag skimmer 2, and restore the normal iron storage and slag skimming functions of the main groove 1. The temperature of the high-temperature molten iron used to melt the solidified molten iron is greater than 1450°C. After the solidified molten iron 5 in the main groove 1 is completely melted and the normal iron storage and slag skimming functions are restored, no other maintenance is required for the main groove 1, and it can be directly used continuously according to the normal production method.

[0041] The iron storage main ditch 1 of a general 2000-class blast furnace has an iron storage capacity of about 20 tons. The heat required to melt 20 tons of solidified molten iron 5 is 20 (t) × 1279 (mJ / t) = 25580 (mJ) (melting 1 ton of iron requires about 1279 mJ of heat). The high-temperature molten iron above 1450°C flows through the main ditch 1 with solidified molten iron 5 and the slag skimmer 2, and the temperature drops by about 50°C, and the heat released is 0.46 (mJ / t·℃) × 50 (℃) = 23 (mJ / t) (the specific heat capacity of iron is 0.46 mJ / t·℃). Therefore, the amount of molten iron above 1450°C required to completely melt the solidified molten iron 5 is 25580 (mJ) ÷ 23 (mJ / t) ≈ 1110 (t). According to the calculation of 500 tons of iron per furnace of a 2000-class blast furnace, after three furnaces of iron are used continuously, the solidified molten iron 5 in the iron storage main ditch 1 and the slag skimmer 2 can be completely melted and flowed away, and the iron storage and slag skimming function of the main ditch 1 can be restored. Blast furnaces of different volumes can be calculated by analogy based on the different iron capacity of the main ditch 1 and the average iron output per furnace.

[0042] The solidified molten iron 5 in the iron storage main ditch 1 and the slag skimmer 2 is completely melted and flows away. After the normal iron storage and slag skimming functions are restored, no other maintenance is required and the machine can be directly used in normal production. There is no need to drain the liquid molten iron in the main ditch 1 for re-repair and re-casting. It can be stopped for maintenance only after it reaches the normal corrosion standard requiring maintenance.

[0043] The thawing method uses the molten iron smelted by the blast furnace itself to melt the main ditch 1 and the solidified molten iron 5 in the slag skimmer 2, which can restore the normal iron storage and slag skimming functions of the main ditch 1. No external equipment or devices are required. Generally, it takes about 6 to 8 hours to dismantle the existing crossbeam 3, about 1 hour to cast the replacement crossbeam 6, and about 6 hours to bake. It will be ready for use in about 13 to 15 hours. During the treatment of special furnace conditions, the iron storage main ditch 1 can generally be completely thawed within 24 hours. The thawing method has the advantages of simple construction and short time consumption, little impact on the normal production of the blast furnace, no safety hazards and environmental pollution factors such as the use of industrial pure oxygen, and the solidified molten iron 5 is fully recycled in the normal production form without incurring economic losses. After the solidified molten iron 5 is completely thawed, the main ditch 1 can still withstand the load of normal production of the blast furnace and complete the life of the next generation of main ditch 1 under normal production conditions.

[0044] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects:

[0045] 1. The overall implementation of the slag skimmer is simple and the manufacturing cost is low. When dismantling the existing crossbeam 3 of the slag skimmer 2, it can be done by using an ordinary handheld small pneumatic pick or a trenching machine that has been configured on site, without the need to call in other large mechanical equipment such as excavators from outside the site. Since there is no intervention of large mechanical equipment or devices, and no mechanical destructive construction methods are used, there is no destructiveness to large concrete building structures such as blast furnace iron-making sites. The manpower and material resources required for construction are very small, and the cost is low.

[0046] 2. No need to use industrial pure oxygen to burn solidified molten iron 5, avoiding the potential safety hazards and environmental pollution caused by using industrial pure oxygen to melt molten iron. This thawing method is not only convenient, fast, safe and environmentally friendly, but also has a short thawing time, saving time, labor and loss.

[0047] 3. The solidified molten iron 5 in the main ditch 1 and the slag skimmer 2 is completely recovered, melted again into ordinary molten iron for steelmaking and utilized, thereby reducing the economic losses caused by ironmaking accidents.

[0048] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A slag skimmer for thawing solidified molten iron in an iron storage type main groove, wherein the slag skimmer is arranged at one end of the main groove, and the molten iron solidifies in both the main groove and the slag skimmer, characterized in that: The skimmer includes a joint, a replacement beam, a small well and an iron ditch, wherein: There are two joints, which are arranged oppositely on the two side walls of the main groove. The two ends of the replacement beam are respectively connected to the two joints, there is a distance between the replacement beam and the upper surface of the solidified molten iron below the replacement beam, and the width of the replacement beam is smaller than the width of the joints. The small well is arranged on one side of the replacement beam, the small well is close to one end of the main groove, and the small well is connected with the main groove on the other side of the replacement beam through the space below the replacement beam. The iron ditch is arranged at one end of the main ditch, and the iron ditch is communicated with the small well.

2. The slag skimmer for thawing solidified molten iron in the iron storage main groove according to claim 1, characterized in that: The width of the replacement beam is 60% of the width of the joint, and the axis of the replacement beam is colinear with the axis of the joint.

3. The slag skimmer for thawing solidified molten iron in the iron storage main groove according to claim 1, characterized in that: The upper surface of the joint, the upper surface of the replacement beam and the upper surface of the main groove are all located in the same plane, and the height of the replacement beam is 0.3m.

4. The slag skimmer for thawing solidified molten iron in the iron storage main groove according to claim 1, characterized in that: The length of the joint is 0.1 m.

5. The slag skimmer for thawing solidified molten iron in the iron storage main groove according to claim 1, characterized in that: The distance between the lower surface of the replacement beam and the upper surface of the solidified molten iron below the replacement beam is greater than or equal to 0.3 m.

6. A method for thawing solidified molten iron in an iron storage type main groove, implemented by using the slag skimmer for thawing solidified molten iron in an iron storage type main groove according to any one of claims 1 to 5, characterized in that: The thawing method comprises the following steps: Step 1, dismantling the existing beam: dismantling the existing beam on the slag skimmer in the main ditch, and retaining 0.1m of refractory material at both ends in the length direction of the existing beam as the joint for casting the replacement beam; Step 2, casting a replacement beam: casting the replacement beam at the location of the existing beam using a mold, wherein the size of the replacement beam is smaller than the size of the existing beam; Step 3, injecting high-temperature molten iron smelted in the blast furnace into the main trench, using the high-temperature molten iron to melt the solidified molten iron in the main trench, and restoring the normal iron storage and slag skimming functions of the main trench.

7. The thawing method according to claim 6, characterized in that: In the step 1, all refractory materials in the depth direction of the existing crossbeam are removed until solidified molten iron can be seen in the depth direction; When the rigidity of the refractory material is high and it is impossible to remove it completely, it should be removed at least to a height of 0.6m below the upper surface of the existing beam.

8. The thawing method according to claim 6, characterized in that: In the step 2, the replacement beam is baked after casting, and the baking time is greater than or equal to 6 hours.

9. The thawing method according to claim 6, characterized in that: In the step 3, the temperature of the high-temperature molten iron used to melt the solidified molten iron is greater than 1450°C.

10. The thawing method according to claim 6, characterized in that: In the step 2, the replacement cross beam is casted by a mold using a main groove castable material. The mold is made of a steel plate, and the thickness of the steel plate used to make the mold is 1 to 3 mm.

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