CN113073167A - KR desulfurization method for high-sulfur molten iron - Google Patents
KR desulfurization method for high-sulfur molten iron Download PDFInfo
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- CN113073167A CN113073167A CN202110274718.XA CN202110274718A CN113073167A CN 113073167 A CN113073167 A CN 113073167A CN 202110274718 A CN202110274718 A CN 202110274718A CN 113073167 A CN113073167 A CN 113073167A
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- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 title claims abstract description 270
- 229910052742 iron Inorganic materials 0.000 title claims abstract description 135
- 238000006477 desulfuration reaction Methods 0.000 title claims abstract description 69
- 230000023556 desulfurization Effects 0.000 title claims abstract description 68
- 229910052717 sulfur Inorganic materials 0.000 title claims abstract description 20
- 239000011593 sulfur Substances 0.000 title claims abstract description 17
- 238000000034 method Methods 0.000 title claims abstract description 13
- 238000003756 stirring Methods 0.000 claims abstract description 93
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims abstract description 42
- 239000007788 liquid Substances 0.000 claims abstract description 31
- 230000004907 flux Effects 0.000 claims abstract description 21
- 229910052757 nitrogen Inorganic materials 0.000 claims abstract description 20
- 238000011282 treatment Methods 0.000 claims abstract description 13
- 238000007664 blowing Methods 0.000 claims abstract description 8
- 239000002893 slag Substances 0.000 claims description 19
- 229910000831 Steel Inorganic materials 0.000 claims description 11
- 239000010959 steel Substances 0.000 claims description 11
- 239000003795 chemical substances by application Substances 0.000 claims description 5
- 229910001873 dinitrogen Inorganic materials 0.000 claims 2
- 238000009529 body temperature measurement Methods 0.000 abstract description 2
- 230000000694 effects Effects 0.000 description 11
- 238000004519 manufacturing process Methods 0.000 description 4
- 238000013019 agitation Methods 0.000 description 3
- 230000003009 desulfurizing effect Effects 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 238000005070 sampling Methods 0.000 description 3
- 238000005266 casting Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000009851 ferrous metallurgy Methods 0.000 description 1
- 238000007790 scraping Methods 0.000 description 1
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- 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
- C21C1/00—Refining of pig-iron; Cast iron
- C21C1/02—Dephosphorising or desulfurising
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Refinement Of Pig-Iron, Manufacture Of Cast Iron, And Steel Manufacture Other Than In Revolving Furnaces (AREA)
Abstract
The invention relates to a KR desulfurization method for high-sulfur molten iron, wherein the molten iron with the mass percent of S being more than or equal to 0.070% is subjected to temperature measurement, the molten iron with the temperature being more than 1280 ℃ directly enters a KR desulfurization device, and the molten iron with the temperature being less than 1280 ℃ is mixed with high-temperature molten iron; after entering a KR desulfurization operation station, slagging off the molten iron for the first time until the exposed area of the molten iron surface accounts for more than 80%; performing KR desulfurization treatment for the first time, adding 30-40% of desulfurization flux into a molten iron tank, stirring, blowing nitrogen, slagging off, and removing the molten iron S to below 0.010% by mass; and (3) secondary desulfurization treatment, namely adding the residual desulfurization flux into molten iron, stirring, blowing nitrogen, and completely removing the liquid level of the molten iron until the mass percent of molten iron S is below 0.002%. The advantages are that: the high-sulfur molten iron is desulfurized effectively by adopting short-range treatment twice, and the desulfurization time is short without resulfurization.
Description
Technical Field
The invention belongs to the field of pretreatment of ferrous metallurgy molten iron, and particularly relates to a method for KR desulfurization of high-sulfur molten iron.
Background
The molten iron entering a steel plant is different in conditions and frequently generates high-sulfur molten iron due to the fact that a blast furnace is out of order, the existing KR desulfurization flux adding mode and operation mode cause long desulfurization time, the desulfurization effect on the high-sulfur molten iron is poor and resulfurization is serious, the flux adding amount is too large, production of variety steel is influenced, casting machine deceleration is caused, quality accidents such as steel change from variety steel to steel are caused, and the desulfurization effect cannot meet the existing production.
Disclosure of Invention
In order to overcome the defects of the prior art, the invention aims to provide the KR desulfurization method for the high-sulfur molten iron, which adopts two short-range treatments to realize good desulfurization effect, meets the existing production requirements, shortens the desulfurization time and does not resulfurize.
In order to achieve the purpose, the invention is realized by the following technical scheme:
a method for KR desulfurization of high-sulfur molten iron comprises the following steps:
1) measuring the temperature of molten iron with the mass percent of S being more than or equal to 0.070%, directly feeding the molten iron with the temperature being more than 1280 ℃ into a KR desulfurization device, mixing the molten iron with the temperature being less than 1280 ℃ with high-temperature molten iron, and ensuring that the temperature of the molten iron fed into the KR desulfurization device is more than 1280 ℃;
2) after entering a KR desulfurization operation station, slagging off the molten iron for the first time until the exposed area of the molten iron surface accounts for more than 80%;
3) performing KR desulfurization treatment for the first time, calculating the addition of desulfurization flux to be 7-9 kg/ton steel according to KR mode, firstly adding 30-40% of desulfurization flux into a molten iron tank, then inserting a stirring paddle below the liquid level of molten iron, controlling the stirring time to be 5-6 minutes, lifting the paddle, pushing a blowing-up slag-driving gun to a position 200-300mm away from the liquid level of molten iron, stopping blowing nitrogen, and controlling the flow of nitrogen to be 2-3Nm3The molten iron liquid level is completely removed, and the first desulfurization control target is reduced to be below 0.010 percent according to the mass percent of the molten iron S;
4) performing secondary desulfurization treatment on the completely removed molten iron, wherein the deep desulfurization mode is adopted in the desulfurization, the residual desulfurization flux (the residual amount after the desulfurization flux is added for the first time according to the calculation result) is added into the molten iron, then the stirring paddle is inserted below the liquid level of the molten iron, the stirring time is controlled to be 7-8 minutes, the blowing-up slag-driving gun is pushed to the position which is 200mm away from the liquid level of the molten iron slag and is stopped after the paddle is lifted, and the nitrogen is blown, wherein the flow of the nitrogen is controlled to be 3-4Nm3Min, removing the molten iron liquid levelAnd the final target of desulfurization is reduced to below 0.002 percent by mass percent of the molten iron S.
5) Covering the surface of the molten iron after slag skimming with 200-300kg covering agent.
The control relation between the depth of molten iron stirred by the stirring paddle and the time in the step 3):
the primary stirring time is 1min, and the stirring depth is 2.8 m;
the secondary stirring time is 2min, and the stirring depth is 3.0 m;
stirring for three times for 3min, and stirring depth of 3.0 m;
stirring for four times for 4min, and stirring depth of 3.4 m;
stirring for five times for 5min, and stirring depth of 3.2 m;
stirring for 6min for six times, and stirring depth of 3.2 m.
The control relation between the depth of molten iron stirred by the stirring paddle and the time in the step 4):
the primary stirring time is 1min, and the stirring depth is 3.0 m;
the secondary stirring time is 2min, and the stirring depth is 3.2 m;
stirring for 3min for the third time, wherein the stirring depth is 3.2 m;
stirring for four times for 4min, and stirring depth of 3.4 m;
stirring for five times for 5min, and stirring depth of 3.0 m;
stirring for six times for 6min, and stirring depth of 3.2 m;
stirring for 7min for seven times, and stirring depth of 3.4 m;
stirring for 8min for eight times, and stirring depth of 3.4 m.
The time for first slag skimming in the step 2) is controlled to be 3-5 minutes.
Compared with the prior art, the invention has the beneficial effects that:
the invention adopts two short-range treatments, realizes good desulfurization effect of the high-sulfur molten iron, and has short desulfurization time without resulfurization. The molten iron desulphurization is improved from 65 percent of the original qualified rate to 95 percent at present, the effect is obvious, and the quality accidents of casting machine speed reduction, steel change from variety steel and the like caused by serious resulfurization due to poor desulphurization effect and influence on the production of variety steel are reduced.
Drawings
FIG. 1 is a diagram of the effect of end-point skimming.
FIG. 2 is a diagram of the effect of primary slag skimming.
Detailed Description
The present invention will be described in detail below with reference to the accompanying drawings, but it should be noted that the present invention is not limited to the following embodiments.
Example 1
The method for desulfurizing KR high-sulfur molten iron comprises the following steps of:
A. and (4) entering a molten iron tank No. 616 of a steel plant, and measuring the temperature of molten iron and sampling, wherein the temperature of the molten iron is 1305 ℃, and the mass percentage content of molten iron S is 0.095%.
B. Putting the molten iron into a No. 1 KR station, and carrying out initial slag skimming on the molten iron, wherein the slag skimming time is 4 minutes, and the liquid level of the molten iron is exposed to 80 percent, which is shown in figure 2.
C. 1.8t of desulfurization flux is required to be added in total in material calculation, and the amount of the desulfurization flux added for the first time is 0.7-0.8 t. The relationship between the paddle and the depth of agitation is shown in Table 1:
TABLE 1
| Stirring time, Min | 1 | 2 | 3 | 4 | 5 | 6 |
| Depth of stirring, M | 2.8 | 3.0 | 3.0 | 3.4 | 3.2 | 3.2 |
After the paddle is lifted, the blowing slag-driving gun is pushed to a position 200mm away from the liquid level of the slag iron and stopped, nitrogen is blown, and the flow rate of the nitrogen is controlled to be 2.5Nm3And/min, completely removing the liquid level of the molten iron, wherein the first desulfurization result is that the molten iron S is removed to 0.009% by mass percent.
D. Carrying out secondary desulfurization treatment on the completely removed molten iron, adding 1-1.1t of KR desulfurization flux into the molten iron, and then inserting a stirring paddle below the liquid level of the molten iron, wherein the control relation of the depth and the time of the stirring paddle is shown in a table 2:
TABLE 2
| Stirring time, Min | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
| Depth of stirring, M | 3.0 | 3.2 | 3.2 | 3.4 | 3.0 | 3.2 | 3.4 |
The stirring time is controlled to be 7 minutes, the blowing-up slag-driving gun is pushed to a position with a height of 130mm from the liquid level of the slag iron after the paddle is lifted, the nitrogen is blown, and the flow rate of the nitrogen is controlled to be 3.2Nm3And/min, completely removing the liquid level of the molten iron, wherein the final goal of desulfurization is that the molten iron S is removed to 0.0018% by mass percent.
E. After the slagging-off of the molten iron is finished, 200kg of covering agent is added into the molten iron tank as shown in figure 1, so that the covering effect is ensured.
Wherein, the main components of the desulfurization flux are CaO and CaF.
Example 2
The method for desulfurizing KR high-sulfur molten iron comprises the following steps of:
A. and (5) putting the molten iron into a factory molten iron tank No. 705, measuring the temperature of molten iron and sampling, wherein the temperature of the molten iron is 1263 ℃, and the mass percentage content of molten iron S is 0.092%.
B. The temperature of the molten iron is lower than 1280 ℃, the basic parameter requirements of KR desulfurization are not met, the tank folding treatment needs to be carried out, the number of the tank folding molten iron tank is 818, the temperature of the molten iron is 1345 ℃, and the mass percentage of the molten iron S is 0.058%. And (3) folding the two molten iron tanks into an empty molten iron tank No. 763 to obtain molten iron, wherein the temperature is measured at 1283 ℃, and the mass percent of the molten iron S is 0.075%.
C. Putting molten iron into a 2# KR station, and carrying out initial slag skimming on the molten iron, wherein the slag skimming time is 3 minutes, and the exposed area of the molten iron liquid level reaches 80%.
D. 1.5t of desulfurization flux is required to be added in total in material calculation, and the amount of the desulfurization flux added for the first time is 0.45-0.6 t. The relationship between the paddles and the depth of agitation is shown in Table 3.
TABLE 3
| Stirring time, Min | 1 | 2 | 3 | 4 | 5 |
| Depth of stirring, M | 2.8 | 3.0 | 3.0 | 3.4 | 3.2 |
After the paddle is lifted, the blowing slag-driving gun is pushed to the position 220mm away from the liquid level of the slag iron and stopped, nitrogen is blown, and the flow rate of the nitrogen is controlled to be 2.3Nm3And Min, completely removing the liquid level of the molten iron, wherein the first desulfurization result is that the molten iron S is removed to 0.008 percent by mass.
E. Carrying out secondary desulfurization treatment on the completely removed molten iron, adding the remaining 0.9-1.05t of KR desulfurization flux into the molten iron, and then inserting a stirring paddle below the liquid level of the molten iron, wherein the control relation of the depth of the stirring paddle and the time is shown in a table 4:
TABLE 4
| Stirring time, Min | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
| Depth of stirring, M | 3.0 | 3.2 | 3.2 | 3.4 | 3.0 | 3.2 | 3.4 |
The stirring time is controlled to be 7 minutes, the blowing-up slag-driving gun is pushed to the position 180mm away from the liquid level of the slag iron after the paddle is lifted, the nitrogen is blown, and the flow rate of the nitrogen is controlled to be 3.0Nm3And Min, completely removing the liquid level of the molten iron, wherein the final goal of desulfurization is that the molten iron S is removed to 0.0016 percent by mass.
F. After the slagging-off of the molten iron is finished, 200kg of covering agent is added into the molten iron tank to ensure the covering effect.
Example 3
The method for desulfurizing KR high-sulfur molten iron comprises the following steps of:
A. and the molten iron is subjected to temperature measurement and sampling by a factory molten iron tank number 683, wherein the temperature of the molten iron is 1356 ℃, and the mass percentage content of the molten iron S is 0.103%.
B. And putting the molten iron into a 2# KR station, and carrying out initial slag skimming on the molten iron, wherein the slag skimming time is 5 minutes, and the exposed area of the molten iron liquid level reaches 80%.
C. 2.1t of desulfurization flux is required to be added in total in material calculation, and the amount of the desulfurization flux added for the first time is 0.65-0.85 t. The relationship between the paddle and the depth of agitation is shown in Table 5:
TABLE 5
| Stirring time, Min | 1 | 2 | 3 | 4 | 5 | 6 |
| Depth of stirring, M | 2.8 | 3.0 | 3.0 | 3.4 | 3.2 | 3.2 |
After the paddle is lifted, the blowing slag-driving gun is pushed to a position 200mm away from the liquid level of the slag iron and stopped, nitrogen is blown, and the flow rate of the nitrogen is controlled to be 2.7Nm3And Min, completely removing the liquid level of the molten iron, wherein the first desulfurization result is that the molten iron S is removed to 0.0010 percent by mass.
D. And (3) carrying out secondary desulfurization treatment on the completely removed molten iron, adding the remaining 1.25-1.45t of KR desulfurization flux into the molten iron, and then inserting a stirring paddle below the liquid level of the molten iron, wherein the control relation of the depth of the stirring paddle and the time is shown in a table 6:
TABLE 6
| Stirring time, Min | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 |
| Depth of stirring, M | 3.0 | 3.2 | 3.2 | 3.4 | 3.0 | 3.2 | 3.4 | 3.4 |
The stirring time is controlled to be 8 minutes, the blowing-up slag-driving gun is pushed to the position with the height of 150mm from the liquid level of the slag iron after the paddle is lifted, the nitrogen is blown, and the flow rate of the nitrogen is controlled to be 3.8Nm3And Min, completely scraping the liquid level of the molten iron, and finally performing desulphurization to the molten iron S to 0.0020 percent by mass.
E. After the slagging-off of the molten iron is finished, 300kg of covering agent is added into the molten iron tank to ensure the covering effect.
Claims (4)
1. A method for KR desulfurization of high-sulfur molten iron is characterized by comprising the following steps:
1) measuring the temperature of molten iron with the mass percent of S being more than or equal to 0.070%, directly feeding the molten iron with the temperature being more than 1280 ℃ into a KR desulfurization device, mixing the molten iron with the temperature being less than 1280 ℃ with high-temperature molten iron, and ensuring that the temperature of the molten iron fed into the KR desulfurization device is more than 1280 ℃;
2) after entering a KR desulfurization operation station, slagging off the molten iron for the first time until the exposed area of the molten iron surface accounts for more than 80%;
3) performing KR desulfurization treatment for the first time, calculating the addition of desulfurization flux to be 7-9 kg/ton steel according to KR mode, firstly adding 30-40% of desulfurization flux into a molten iron tank, then inserting a stirring paddle below the liquid level of molten iron, controlling the stirring time to be 5-6 minutes, lifting the paddle, pushing a blowing-up slag-driving gun to a position 200-300mm away from the liquid level of molten iron, stopping blowing nitrogen, and controlling the flow of nitrogen to be 2-3Nm3The molten iron liquid level is completely removed, and the first desulfurization control target is reduced to be below 0.010 percent according to the mass percent of the molten iron S;
4) carrying out secondary desulfurization treatment on the completely removed molten iron, wherein the deep desulfurization mode is adopted in the desulfurization, the residual desulfurization flux is added into the molten iron according to the calculation amount in the step 3), then a stirring paddle is inserted below the liquid level of the molten iron, the stirring time is controlled to be 7-8 minutes, and after the paddle is lifted, a blowing-up slag-removing gun is pushed to be 100 minutes away from the liquid level of the slag ironStopping at a height of-200 mm, blowing nitrogen gas, controlling the nitrogen gas flow at 3-4Nm3And/min, completely removing the liquid level of the molten iron, and removing the final desulfurization target to be below 0.002 percent according to the mass percent of the molten iron S.
5) Covering the surface of the molten iron after slag skimming with 200-300kg covering agent.
2. The KR desulfurization method for high-sulfur molten iron as claimed in claim 1, wherein the depth of the stirring paddle stirring the molten iron in step 3) is related to the time control:
the primary stirring time is 1min, and the stirring depth is 2.8 m;
the secondary stirring time is 2min, and the stirring depth is 3.0 m;
stirring for three times for 3min, and stirring depth of 3.0 m;
stirring for four times for 4min, and stirring depth of 3.4 m;
stirring for five times for 5min, and stirring depth of 3.2 m;
stirring for 6min for six times, and stirring depth of 3.2 m.
3. The KR desulfurization method for high-sulfur molten iron as claimed in claim 1, wherein the depth of the stirring paddle stirring the molten iron in step 4) is related to the time control:
the primary stirring time is 1min, and the stirring depth is 3.0 m;
the secondary stirring time is 2min, and the stirring depth is 3.2 m;
stirring for 3min for the third time, wherein the stirring depth is 3.2 m;
stirring for four times for 4min, and stirring depth of 3.4 m;
stirring for five times for 5min, and stirring depth of 3.0 m;
stirring for six times for 6min, and stirring depth of 3.2 m;
stirring for 7min for seven times, and stirring depth of 3.4 m;
stirring for 8min for eight times, and stirring depth of 3.4 m.
4. The KR desulfuration method for high-sulfur molten iron as claimed in claim 1, wherein the time for the first slag skimming in step 2) is controlled to be 3-5 minutes.
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH1088216A (en) * | 1996-09-13 | 1998-04-07 | Nkk Corp | Method for desulfurizing molten iron |
| CN108588318A (en) * | 2018-05-22 | 2018-09-28 | 武汉钢铁有限公司 | Molten iron mechanical agitation efficient low-consume sulfur method |
| CN110042200A (en) * | 2019-04-09 | 2019-07-23 | 鞍钢股份有限公司 | Smelting method of ultra-low sulfur steel |
| CN110241283A (en) * | 2019-06-13 | 2019-09-17 | 首钢集团有限公司 | A kind of converter of desulfurization slag iron utilizes method |
| CN111394535A (en) * | 2020-03-30 | 2020-07-10 | 安徽工业大学 | Step-by-step KR stirring desulfurization method for molten iron |
-
2021
- 2021-03-15 CN CN202110274718.XA patent/CN113073167A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH1088216A (en) * | 1996-09-13 | 1998-04-07 | Nkk Corp | Method for desulfurizing molten iron |
| CN108588318A (en) * | 2018-05-22 | 2018-09-28 | 武汉钢铁有限公司 | Molten iron mechanical agitation efficient low-consume sulfur method |
| CN110042200A (en) * | 2019-04-09 | 2019-07-23 | 鞍钢股份有限公司 | Smelting method of ultra-low sulfur steel |
| CN110241283A (en) * | 2019-06-13 | 2019-09-17 | 首钢集团有限公司 | A kind of converter of desulfurization slag iron utilizes method |
| CN111394535A (en) * | 2020-03-30 | 2020-07-10 | 安徽工业大学 | Step-by-step KR stirring desulfurization method for molten iron |
Non-Patent Citations (2)
| Title |
|---|
| 李志丹等: "钒钛铁水KR脱硫控制渣铁不分工艺实践", 《中国金属通报》 * |
| 魏琨等: "武钢二炼钢KR铁水脱硫生产工艺优化实践", 《钢铁研究》 * |
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Application publication date: 20210706 |