CN112853032A - Method for quickly protecting large front surface of converter - Google Patents
Method for quickly protecting large front surface of converter Download PDFInfo
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- CN112853032A CN112853032A CN202110032769.1A CN202110032769A CN112853032A CN 112853032 A CN112853032 A CN 112853032A CN 202110032769 A CN202110032769 A CN 202110032769A CN 112853032 A CN112853032 A CN 112853032A
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- converter
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- slag
- waste
- magnesite
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- 238000000034 method Methods 0.000 title claims abstract description 43
- 239000002893 slag Substances 0.000 claims abstract description 81
- 239000002699 waste material Substances 0.000 claims abstract description 60
- 239000001095 magnesium carbonate Substances 0.000 claims abstract description 40
- 229910000021 magnesium carbonate Inorganic materials 0.000 claims abstract description 40
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 39
- 239000010959 steel Substances 0.000 claims abstract description 39
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 37
- 239000000571 coke Substances 0.000 claims abstract description 37
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 37
- 239000001301 oxygen Substances 0.000 claims abstract description 37
- 235000014380 magnesium carbonate Nutrition 0.000 claims abstract description 32
- ZLNQQNXFFQJAID-UHFFFAOYSA-L magnesium carbonate Chemical compound [Mg+2].[O-]C([O-])=O ZLNQQNXFFQJAID-UHFFFAOYSA-L 0.000 claims abstract description 32
- 230000000694 effects Effects 0.000 claims abstract description 27
- 238000010079 rubber tapping Methods 0.000 claims abstract description 18
- 238000005245 sintering Methods 0.000 claims abstract description 17
- 239000000463 material Substances 0.000 claims description 19
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 9
- 229910052799 carbon Inorganic materials 0.000 claims description 9
- 238000007667 floating Methods 0.000 claims description 9
- 239000012535 impurity Substances 0.000 claims description 8
- 239000000203 mixture Substances 0.000 claims description 8
- 238000005096 rolling process Methods 0.000 claims description 7
- 238000005496 tempering Methods 0.000 claims description 4
- 238000005520 cutting process Methods 0.000 claims description 3
- QRSFFHRCBYCWBS-UHFFFAOYSA-N [O].[O] Chemical compound [O].[O] QRSFFHRCBYCWBS-UHFFFAOYSA-N 0.000 claims 1
- 239000000126 substance Substances 0.000 abstract description 16
- 239000011150 reinforced concrete Substances 0.000 abstract description 4
- 230000009286 beneficial effect Effects 0.000 abstract description 3
- 238000005272 metallurgy Methods 0.000 abstract description 2
- 230000001105 regulatory effect Effects 0.000 abstract 1
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 20
- 238000007664 blowing Methods 0.000 description 11
- 238000004519 manufacturing process Methods 0.000 description 9
- 238000007599 discharging Methods 0.000 description 7
- 229910000805 Pig iron Inorganic materials 0.000 description 6
- 230000003628 erosive effect Effects 0.000 description 5
- 239000013589 supplement Substances 0.000 description 5
- ODINCKMPIJJUCX-UHFFFAOYSA-N Calcium oxide Chemical compound [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 description 4
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 4
- 239000011449 brick Substances 0.000 description 4
- 229910052749 magnesium Inorganic materials 0.000 description 4
- 239000011777 magnesium Substances 0.000 description 4
- 238000003723 Smelting Methods 0.000 description 3
- 230000007797 corrosion Effects 0.000 description 3
- 238000005260 corrosion Methods 0.000 description 3
- 238000002844 melting Methods 0.000 description 3
- 230000008018 melting Effects 0.000 description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 239000000292 calcium oxide Substances 0.000 description 2
- 235000012255 calcium oxide Nutrition 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 229910000514 dolomite Inorganic materials 0.000 description 2
- 239000010459 dolomite Substances 0.000 description 2
- 238000009628 steelmaking Methods 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 235000013372 meat Nutrition 0.000 description 1
- CSJDCSCTVDEHRN-UHFFFAOYSA-N methane;molecular oxygen Chemical compound C.O=O CSJDCSCTVDEHRN-UHFFFAOYSA-N 0.000 description 1
- 238000012946 outsourcing Methods 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 230000008646 thermal stress Effects 0.000 description 1
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
- C21C5/28—Manufacture of steel in the converter
- C21C5/42—Constructional features of converters
- C21C5/44—Refractory linings
- C21C5/441—Equipment used for making or repairing linings
- C21C5/443—Hot fettling; Flame gunning
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
- C21C5/28—Manufacture of steel in the converter
- C21C5/36—Processes yielding slags of special composition
Abstract
The invention belongs to the field of metallurgy, and particularly relates to a large-area rapid furnace protection method in front of a converter. Firstly, utilizing tapping time, adding nut coke according to the oxygen activity value determined by the end point of the converter to deoxidize and regulate slag of the final slag, reducing the oxidability of the slag, regulating FeO of the final slag to 7% -10%, then using a waste steel hopper to pour raw magnesite and bar waste crop into the converter from the front of the converter, quickly decomposing the raw magnesite into high-melting-point substances MgO under the high-temperature environment in the converter, and absorbing a large amount of heat to ensure that the high-melting-point substances MgO and C in the slag2S、C3S, the steel bars are quickly precipitated and condensed, and the waste cut ends of the steel bars are adhered to form a structure similar to reinforced concrete and firmly combined on a furnace lining. The method has the advantages of simple operation, low cost, short sintering time and long furnace protection period, is beneficial to improving the operation rate of the converter, and helps enterprises to increase the yield and benefit.
Description
Technical Field
The invention relates to the field of metallurgy, in particular to a method for quickly protecting a large front surface of a converter.
Background
The front surface of the converter has various names, such as slag surface, steel facing surface and the like. In the oxygen top-blown converter steelmaking, the lining of the converter is subjected to mechanical impact, alternating thermal stress and severe chemical erosion in a strong oxidation environment, and the lining of the converter is eroded, so that a perfect furnace protection process is required to complete a furnace protection task. In the whole steel-making process of the converter, the front surface of the converter is easy to be damaged by mechanical impact when waste steel and molten iron are added, and the converter is the position with the fastest corrosion loss in a furnace lining and is also the key position with hidden danger of furnace penetration. At present, the converter in the industry adopts magnesium large-surface repairing materials for maintaining the front large surface, the repairing materials are sintered by utilizing the heat of the converter lining, the thickness of the lining is increased by the sintered repairing materials, and the safety of the lining is ensured. However, the method has long time for sintering the repairing mass, and the sintering time is guaranteed to be more than 30min, so that the operating rate of the converter is reduced.
The existing converter protection technology carries out some improvements on the protection method. Publication No. CN106995866A discloses a low-cost high-efficiency converter fettling process, which comprises the following steps: and (3) swinging the converter to an inclination angle of 60-70 degrees according to the slag supplement surface part, adding the prepared furnace supplement bricks into the converter according to the proportion of adding 200-300 furnace supplement bricks into an 80-ton converter, then swinging the converter to 85-95 degrees, waiting for 35-45min, increasing the viscosity of the slag, wrapping the furnace supplement bricks and adhering the furnace supplement bricks on a furnace lining. The method needs more than 35 minutes for fettling time each time, has 8 hours of using time, and has low production efficiency due to long fettling time.
The publication No. CN103194569A discloses a pig iron block fettling method, which is characterized in that the slag splashing operation is not carried out after the converter blowing is finished and steel tapping, the converter is moved to the position below the material loading position and is inclined to the position right below the fettling position in the converter, the pig iron blocks are added, the converter is started after the converter is kept still for 2 to 3 minutes, the slag splashing is carried out for 2 to 3 minutes, and the next blowing is carried out after the slag dumping. The method utilizes pig iron to carry out furnace repairing, although the furnace repairing time is shortened, the melting point of the pig iron is only 1200-1300 ℃, so the high-temperature corrosion resistance of the pig iron is slightly poor, when the end temperature of the converter reaches over 1630 ℃, the condition that the furnace lining is peeled off in a large area due to the melting of the pig iron is easily caused, and the safety risk of the furnace lining is increased.
Publication No. CN108728603A discloses a method for quickly repairing a furnace, which comprises the following steps: adding a magnesium-containing material into the furnace needing to be fettled, and controlling the MgO content in the furnace slag to be 8-10% at the smelting end point; and (3) adding raw dolomite or quicklime into the furnace after the steel is placed, adjusting the raw dolomite or quicklime to be positioned in a to-be-repaired area, splashing slag after 8-10min, and completing furnace repairing. According to the method, a magnesium-containing material is added in the smelting process, so that the MgO content in the slag is ensured to be 8-10%, but the MgO content in the slag is more than 7.5% in the smelting process, the slag is easily dried back, dephosphorization is not facilitated, and dry-back splashing is easily caused. In addition, the furnace repairing method mainly depends on MgO furnace protection, so that the impact resistance is insufficient, and when large pieces of scrap steel (heavy waste) are added, the front large surface can still be damaged due to huge impact force, so that pit-shaped depressions are formed, and the local furnace lining is thinned.
Disclosure of Invention
The invention aims to provide a method for quickly repairing a large front surface of a converter, which is characterized in that the end point carbon content and the end slag MgO content of the converter do not need to be accurately controlled, the time for protecting the converter each time is less than or equal to 10 minutes, the using time is more than or equal to 24 hours, the high-temperature corrosion resistance and the mechanical impact resistance are strong, especially the impact force of large scrap (heavy waste) is strong, and the converter can be used for more than 24 hours under the condition that the average end point temperature of the converter is more than 1640 ℃ after one-time furnace protection.
In order to achieve the purpose, the invention adopts the following technical scheme:
a method for quickly protecting the front large surface of a converter comprises the steps of firstly, utilizing the time of tapping, adding coke breeze according to the fixed oxygen activity value of the end point of the converter to deoxidize the final slag, and reducing the oxidability of the slag; then, a waste steel hopper is used for pouring magnesite raw ore and waste cut ends of bars into the furnace from the front of the furnace, the magnesite raw ore is quickly decomposed into high-melting-point substances MgO in the high-temperature environment in the furnace, and a large amount of heat is absorbed to ensure that the high-melting-point substances MgO and C in the slag2S、C3S is precipitated and condensed, the waste cut ends of the bars are adhered to form a structure similar to reinforced concrete, the furnace is firmly combined on a furnace lining, the furnace can be used for more than 24 hours under the condition that the average end point temperature of the converter is more than 1640 ℃ after one-time furnace protection, and the purposes of quickly repairing the furnace and holding the furnace are achievedThe purpose of long-term use.
The method comprises the following specific steps:
1) and (5) after the blowing is finished, carrying out oxygen determination operation on the blowing terminal point of the converter by using a converter sublance system.
2) And (4) determining the oxygen activity value according to the end point, and synchronously deoxidizing and tempering the slag by using the coke oven after the furnace in the tapping process.
Wherein the nut coke comprises the following components in percentage by mass: 6-13% of ash, 1-6% of volatile matter and 85-92% of fixed carbon. Granularity: less than or equal to 10 mm.
The usage amount of the coke dices in the 120T converter is as follows: when the oxygen activity value of the fixed oxygen at the end point of the converter is less than 600ppm, 30kg of coke breeze is added; when the oxygen activity value of the converter at the end point is determined to be 600-800 ppm, 40kg of coke breeze is added; 50kg of coke breeze is added when the oxygen activity value at the end point of the converter is determined to be 800-1000 ppm, and 60kg of coke breeze is added when the oxygen activity value at the end point of the converter is determined to be more than 1000 ppm.
3) Quantitative magnesite and rolling material waste crop ends are loaded into the waste steel hopper in advance according to the area of the fettling furnace.
Wherein, the main component of raw magnesite is MgCO3The chemical composition of MgO: 40 to 46% of CO2: 45-50%, FeO less than or equal to 9%, and impurities less than or equal to 8%.
The waste cutting head of the bar is a waste steel material produced in the production of a rolling line, and the size of the waste cutting head is as follows: the diameter phi is 30 mm-60 mm, and the length is 100 mm-600 mm.
The addition of magnesite and waste cut ends of rolled materials is adjusted according to the area of the fettling furnace. The area of the fettling furnace is more than 3m2The adding amount of the magnesite is 1.3 t-1.8 t, and the adding amount of the waste crop ends of the rolled stock is 0.8 t-1.2 t; the area of the fettling furnace is less than or equal to 3m2The adding amount of the magnesite is 0.8 t-1.2 t, and the adding amount of the waste cut ends of the bars is 0.5 t-0.7 t. The specific amounts added are shown in Table 1.
4) After steel discharging is finished, the furnace is shaken to 60 ℃, and magnesite and bar waste crop ends in the waste steel hopper are rapidly added into the furnace. And then quickly shaking the furnace to about 95 ℃ and staying for 10 seconds, finally shaking the furnace to 87-90 ℃, and standing and sintering for about 4-6 min.
5) And performing slag splashing furnace protection after sintering is finished, wherein the slag splashing time is less than or equal to 2 min.
6) And (4) after slag splashing, carrying out slag pouring operation, and pouring all floating slag in the furnace into a slag pot.
The materials for repairing the furnace are proportioned according to the following table 1:
TABLE 1
The converter protection method of the invention takes 24 hours as a protection period, namely, after 48 converters are circularly produced by the converter, the operation of the converter protection method is carried out once.
Compared with the prior art, the invention has the beneficial effects that:
(1) the method provided by the invention can meet the furnace protection requirement only within 8-10 minutes in the whole furnace protection process, and can be used for more than 24 hours under the condition that the average end point temperature of the converter is more than 1640 ℃ after one-time furnace protection, so that the aims of quick furnace repairing and durable use are fulfilled, and the production efficiency of the converter is greatly improved.
(2) The method provided by the invention does not need to accurately control the end point carbon content and the MgO content of the end slag of the converter (MgO is more than 7.5 percent to seriously influence the slagging condition of the converter and reduce the dephosphorization rate of the converter)
(3) The control method for adjusting the FeO in the final slag provided by the invention is based on a large number of tests, and the FeO in the final slag can be accurately adjusted to 7-12% according to the oxygen setting value of a converter sublance system by the adding amount of the coke breeze.
(4) The timing of adding the coke dices is selected as the time of adding the coke dices after the furnace in the tapping process, and the blowing time and the furnace repairing time are not occupied.
(5) The invention has the special effects that a structure similar to reinforced concrete is formed and firmly combined on a furnace lining, the structure has strong chemical and physical erosion resistance, especially outstanding mechanical impact erosion resistance, and the condition that when massive waste steel (heavy waste) is added, the front large surface is impacted by huge impact force to form pit-shaped dent damage can be avoided. Greatly improves the use safety of the furnace lining.
(6) The invention utilizes magnesite raw ore and the waste cut ends of rolling material to carry out furnace repairing, wherein the magnesite raw ore has low price, and the waste cut ends of rolling material are self-produced waste steel of a steel mill without outsourcing, thereby reducing the furnace repairing cost and having good economic benefit.
A method for quickly repairing the front large surface of a converter comprises the steps of determining the oxygen activity according to the end point of the converter, adding a proper amount of coke, and deoxidizing and tempering slag by using a carbon-oxygen reaction; magnesite and waste cut ends of bars are added into the furnace at the same time, raw magnesite is quickly decomposed into high-melting-point substances MgO in the high-temperature environment in the furnace, and a large amount of heat is absorbed to ensure that the high-melting-point substances MgO and C in the slag2S、C3S quickly separates out and condenses, and sticks the waste cut ends of the bars to form a structure similar to reinforced concrete, and the structure is firmly combined on a furnace lining, and has strong chemical and physical erosion resistance, especially outstanding mechanical impact erosion resistance.
After the furnace repairing is carried out by adopting the method, the furnace protection effect can be continuously maintained for 24 hours, and the method for carrying out the front large-area furnace repairing by using the magnesium large-area furnace repairing material is completely replaced. In addition, the method is simple, low in cost, short in sintering time and long in furnace protection period, and is beneficial to improving the operation rate of the converter.
The method for quickly repairing the large front surface of the converter is used for 24 hours as a furnace protection period, namely, after the converter continuously produces for 24 hours, the operation of the method for quickly repairing the large front surface of the converter is carried out once.
Drawings
FIG. 1 is a process flow diagram of the present invention.
Detailed Description
The method of the present invention will be specifically described below with reference to specific examples.
Example 1:
1) at the blowing end point of the converter, oxygen is determined by using a sublance TSO, and the oxygen activity is 500 ppm.
2) According to the oxygen activity of 500ppm, the amount of the coke dices is 30 kg. And during the period from tapping for 1min to the end of tapping, throwing the coke cubes into the surface of the slag in the furnace. The nut coke comprises the following components in percentage by mass: 10% of ash, 4% of volatile matter and 86% of fixed carbon. Granularity: less than or equal to 10 mm.
3) Determining the area of the furnace to be repaired to be 4m2Magnesite and waste cut ends of bar materials are filled into the waste steel hopper for 1.5t in advance, and the waste cut ends of the bar materials are filled into the waste steel hopper for 1.0 t. Magnesite components: chemical composition MgO: 42% of CO2：48％，FeO：7％，The balance being impurities.
4) After steel discharging is finished, the furnace is shaken to 60 ℃, and magnesite and bar waste crop ends in the waste steel hopper are rapidly added into the furnace. And then quickly shaking the furnace to about 95 ℃ and staying for 10 seconds, finally shaking the furnace to 87-90 ℃, and standing and sintering for 6 min.
5) Slag splashing and furnace protection are carried out for 2 min.
6) And (4) after slag splashing, carrying out slag pouring operation, and pouring all floating slag in the furnace into a slag pot.
7) Actual production conditions
TABLE 2
Example 2:
1) at the blowing end point of the converter, oxygen is determined by using a sublance TSO, and the oxygen activity is 700 ppm.
2) According to the oxygen activity of 700ppm, the amount of the coke dices is 40 kg. And during the period from tapping for 1min to the end of tapping, throwing the coke cubes into the surface of the slag in the furnace. The nut coke comprises the following components in percentage by mass: 8% of ash, 6% of volatile matter and 86% of fixed carbon. Granularity: less than or equal to 10 mm.
3) Determining the area of the furnace to be repaired to be 2m2Magnesite and waste bar ends are put into the waste steel hopper in advance for 1.0t and 0.6t respectively. Magnesite components: chemical composition MgO: 41% of CO2: 47%, FeO: 9 percent, and the balance of impurities.
4) After steel discharging is finished, the furnace is shaken to 60 ℃, and magnesite and bar waste crop ends in the waste steel hopper are rapidly added into the furnace. And then quickly shaking the furnace to about 95 ℃ and staying for 10 seconds, finally shaking the furnace to 87-90 ℃, and standing and sintering for 4 min.
5) Slag splashing and furnace protection are carried out for 2 min.
6) And (4) after slag splashing, carrying out slag pouring operation, and pouring all floating slag in the furnace into a slag pot.
7) Actual production conditions
TABLE 3
Example 3:
1) at the blowing end point of the converter, oxygen is determined by using a sublance TSO, and the oxygen activity is 900 ppm.
2) According to the oxygen activity of 900ppm, the amount of the coke is determined to be 50 kg. And during the period from tapping for 1min to the end of tapping, throwing the coke cubes into the surface of the slag in the furnace. The nut coke comprises the following components in percentage by mass: 12% of ash, 1% of volatile matter and 87% of fixed carbon. Granularity: less than or equal to 10 mm.
3) Determining the area of the furnace to be repaired to be 5m2Magnesite and waste cut ends of bar materials are filled into the waste steel hopper for 1.5t in advance, and the waste cut ends of the bar materials are filled into the waste steel hopper for 1.0 t. Magnesite components: chemical composition MgO: 40% of CO2: 46%, FeO: 9 percent, and the balance of impurities.
4) After steel discharging is finished, the furnace is shaken to 60 ℃, and magnesite and bar waste crop ends in the waste steel hopper are rapidly added into the furnace. And then quickly shaking the furnace to about 95 ℃ and staying for 10 seconds, finally shaking the furnace to 87-90 ℃, and standing and sintering for 6 min.
5) Slag splashing and furnace protection are carried out for 2 min.
6) And (4) after slag splashing, carrying out slag pouring operation, and pouring all floating slag in the furnace into a slag pot.
7) Actual production conditions
TABLE 4
Example 4:
1) at the blowing end point of the converter, oxygen is determined by using a sublance TSO, and the oxygen activity is 1300 ppm.
2) According to the oxygen activity of 1300ppm, the amount of the coke dices is determined to be 60 kg. And during the period from tapping for 1min to the end of tapping, throwing the coke cubes into the surface of the slag in the furnace. The nut coke comprises the following components in percentage by mass: 13% of ash, 1% of volatile matter and 86% of fixed carbon. Granularity: less than or equal to 10 mm.
3) Determining the area of the furnace to be repaired to be 2m2Magnesite and waste bar ends are put into the waste steel hopper in advance for 1.0t and 0.6t respectively. Magnesite components: chemical composition MgO: 43% of CO2: 48%, FeO: 6 percent and the balance of impurities.
4) After steel discharging is finished, the furnace is shaken to 60 ℃, and magnesite and bar waste crop ends in the waste steel hopper are rapidly added into the furnace. And then quickly shaking the furnace to about 95 ℃ and staying for 10 seconds, finally shaking the furnace to 87-90 ℃, and standing and sintering for 4 min.
5) Slag splashing and furnace protection are carried out for 2 min.
6) And (4) after slag splashing, carrying out slag pouring operation, and pouring all floating slag in the furnace into a slag pot.
7) Actual production conditions
TABLE 5
Comparative example 1
1) At the blowing end point of the converter, oxygen is determined by using a sublance TSO, and the oxygen activity is 1300 ppm.
2) The nut coke is not added after the furnace.
3) Determining the area of the furnace to be repaired to be 2m2Magnesite and waste bar ends are put into the waste steel hopper in advance for 1.0t and 0.6t respectively. Magnesite components: chemical composition MgO: 43% of CO2: 48%, FeO: 6 percent and the balance of impurities.
4) After steel discharging is finished, the furnace is shaken to 60 ℃, and magnesite and bar waste crop ends in the waste steel hopper are rapidly added into the furnace. And then quickly shaking the furnace to about 95 ℃ for 10 seconds, finally shaking the furnace to 87-90 ℃, and standing and sintering for 15min (the ferrous oxide in the slag is high, the melting point of the slag is low, so that a lower temperature is required, and the sintering time needs to be prolonged).
5) Slag splashing and furnace protection are carried out for 2 min.
6) And (4) after slag splashing, carrying out slag pouring operation, and pouring all floating slag in the furnace into a slag pot.
7) Actual production conditions
TABLE 6
Comparative example 2
1) At the blowing end point of the converter, oxygen is determined by using a sublance TSO, and the oxygen activity is 700 ppm.
2) According to the oxygen activity of 700ppm, the amount of the coke dices is 40 kg. And during the period from tapping for 1min to the end of tapping, throwing the coke cubes into the surface of the slag in the furnace. The coke-oven-dried meat comprises the following components: 8% of ash, 6% of volatile matter and 86% of fixed carbon. Granularity: less than or equal to 10 mm.
3) Determining the area of the furnace to be repaired to be 2m2Magnesite is loaded into the scrap steel bucket for 1.0t in advance. Magnesite components: chemical composition MgO: 41% of CO2: 47%, FeO: 9 percent, and the balance of impurities.
4) After steel discharging is finished, the furnace is shaken to 60 ℃, and magnesite in the waste steel bucket is rapidly added into the furnace. And then quickly shaking the furnace to about 95 ℃ and staying for 10 seconds, finally shaking the furnace to 87-90 ℃, and standing and sintering for 4 min.
5) Slag splashing and furnace protection are carried out for 2 min.
6) And (4) after slag splashing, carrying out slag pouring operation, and pouring all floating slag in the furnace into a slag pot.
7) Actual production conditions
TABLE 7
Claims (6)
1. A method for quickly protecting a large front surface of a converter is characterized by comprising the following steps: firstly, adding the coke pieces into the final slag to deoxidize according to the determined oxygen activity value at the end point of the converter by utilizing the tapping opportunity, and then pouring magnesite raw ore and the waste cut ends of the bars into the converter from the front of the converter by using a waste steel hopper; then quickly shaking the furnace and then standing and sintering; and after sintering, slag splashing and furnace protection are carried out, and floating furnace slag in the furnace is completely poured into a slag tank.
2. The method for rapidly protecting the front large face of the converter according to claim 1, which is characterized by comprising the following steps:
1) in the tapping process, a converter sublance system is used for carrying out oxygen determination on the end point of the converter;
2) determining the oxygen-oxygen activity value according to the end point, and deoxidizing and tempering the slag by using the nut coke behind the furnace;
3) magnesite and rolling material waste crop ends are filled into the waste steel hopper in advance according to the area of the fettling furnace;
4) after tapping, shaking the furnace to 60 ℃, quickly adding magnesite and rolling material waste crop ends in the waste steel hopper into the furnace, then quickly shaking the furnace to 95 ℃ for 10 seconds, finally shaking the furnace to 87-90 ℃, and standing and sintering for 4-6 min;
5) after sintering, slag splashing protection is carried out, and slag splashing time is less than or equal to 2 min;
6) and (4) after slag splashing, carrying out slag pouring operation, and pouring all floating slag in the furnace into a slag pot.
3. The method for rapidly protecting the large front surface of the converter according to claim 2, wherein the composition of the coke breeze in the step (2) comprises the following components in percentage by mass: 6-13% of ash, 1-6% of volatile matter, 85-92% of fixed carbon and less than or equal to 10mm of granularity.
4. The method for rapidly protecting the large front face of the converter according to claim 2, wherein the oxygen activity value is determined according to the end point in the step (2), and the coke breeze is used for deoxidizing and tempering the slag after the converter, and the coke breeze dosage on a 120T converter is as follows: when the oxygen activity value of the fixed oxygen at the end point of the converter is less than 600ppm, 30kg of coke breeze is added; when the oxygen activity value of the converter at the end point is determined to be 600-800 ppm, 40kg of coke breeze is added; when the oxygen activity value of the converter at the end point is determined to be 800-1000 ppm, 50kg of coke breeze is added; when the oxygen content at the end point of the converter is more than 1000ppm, 60kg of coke breeze is added.
5. The converter front large-area rapid furnace protection method according to claim 2, characterized in that the magnesite in the step (3) comprises the following components by mass percent: MgO: 40 to 46% of CO2: 45-50%, FeO less than or equal to 9%, and impurities less than or equal to 8%; the size of the waste cutting head of the rolling line is as follows: the diameter phi is 30 mm-60 mm, and the length is 100 mm-600 m.
6. The method for rapidly protecting the large front face of the converter according to claim 2, wherein the magnesite and rolled stock scrap crop loading amount in the step (3) is adjusted according to the area of the converter. The area of the fettling furnace is more than 3m2Magnesite oreThe addition amount is 1.3 t-1.8 t, and the addition amount of the waste crop ends of the rolled stock is 0.8 t-1.2 t; the area of the fettling furnace is less than or equal to 3m2The adding amount of the magnesite is 0.8 t-1.2 t, and the adding amount of the waste cut ends of the bars is 0.5 t-0.7 t.
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| CN114657309A (en) * | 2022-02-21 | 2022-06-24 | 阳春新钢铁有限责任公司 | Furnace protection method with low iron loss |
| CN114774623A (en) * | 2022-05-18 | 2022-07-22 | 阳春新钢铁有限责任公司 | Method for quickly repairing furnace by using magnesite |
| CN114854931A (en) * | 2022-05-09 | 2022-08-05 | 首钢水城钢铁（集团）有限责任公司 | Method for quickly shimming converter lining by using steel bars |
| CN114959165A (en) * | 2022-05-18 | 2022-08-30 | 玉溪新兴钢铁有限公司 | Converter steelmaking furnace protecting method |
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| CN114959165A (en) * | 2022-05-18 | 2022-08-30 | 玉溪新兴钢铁有限公司 | Converter steelmaking furnace protecting method |
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