阅读说明：本技术 一种利用中间包耐材转炉炼钢造渣的方法 (Method for converter steelmaking slagging by using tundish refractory ) 是由 黄山 高海 何晴 张东 王金星 苏克文 范英全 王俊豪 于 2021-08-18 设计创作，主要内容包括：一种利用中间包耐材转炉炼钢造渣的方法,属于炼钢技术领域。该方法在转炉吹炼过程中,根据转炉内炉渣反应情况,加入造渣料,快速化渣、造渣,得到合格钢水；转炉溅渣时加入中间包耐材破碎料、白云石,对炉渣进行调渣处理。本发明能有效的提高炉渣中氧化镁含量,减少炉衬砖的侵蚀,提高转炉炉龄。同时实现了中间包废弃耐材的回收利用,降低了转炉炼钢造渣的成本。(A method for converter steelmaking slagging by using tundish refractory belongs to the technical field of steelmaking. In the method, in the converter blowing process, according to the slag reaction condition in the converter, a slag making material is added, and slag is rapidly melted and formed to obtain qualified molten steel; and adding a tundish refractory material crushing material and dolomite when the converter splashes slag, and carrying out slag mixing treatment on the slag. The invention can effectively improve the content of magnesium oxide in the slag, reduce the erosion of the lining brick and improve the service life of the converter. Meanwhile, the recycling of the waste refractory materials of the tundish is realized, and the cost of converter steelmaking slagging is reduced.)

1. A method for converter steelmaking slagging by using tundish refractory materials is characterized in that in the converter blowing process, according to the slag reaction condition in a converter, slagging materials are added, and rapid slagging and slagging are carried out to obtain qualified molten steel; the converter converting process specifically comprises the following steps:

(1) after the converter is started to blow, adding 2-5 kg/t steel and 5-10 kg/t steel of tundish refractory material and lime into the converter, and adding 0-10 kg/t ladle slag within 2min of blowing;

(2) within 5-10 min of blowing, adding 0-5 kg/t steel, 5-15 kg/t steel and 5-10 kg/t steel of tundish refractory materials;

(3) after blowing for 10min, carrying out bomb-throwing temperature measurement if T is detected_{Fruit of Chinese wolfberry}≥T_{Eyes of a user}+10, adding 2-10kg/t steel of tundish refractory material and 0-5 kg/t steel of lime for temperature adjustment; the T is_{Fruit of Chinese wolfberry}Measured temperature, T, for projectile throwing_{Eyes of a user}Is the target temperature of the steel-making model of the steel grade.

2. The method for steelmaking and slagging using a tundish refractory converter according to claim 1, wherein the method comprises the following steps: the method also comprises the step of adding a tundish refractory material and dolomite when the converter splashes slag, and carrying out slag regulation treatment on the slag.

3. The method for steelmaking and slagging using a tundish refractory converter according to claim 2, wherein the method comprises the following steps: when the converter splashes slag, 2-5 kg/t steel and 2-5 kg/t steel of tundish refractory material and dolomite are added.

4. The method for steelmaking and slagging using a tundish refractory converter according to claim 3, wherein the method comprises the following steps: the content of MgO in the tundish refractory material is more than or equal to 85wt%, and the granularity is 5-30 mm.

5. The method for steelmaking and slagging using a tundish refractory converter according to claim 4, wherein the method comprises the following steps: the ladle slag is the residual of the crushed and screened continuous casting ladle, the FeO content is more than or equal to 17wt%, and the granularity is 15-35 mm.

6. The method for slagging in converter steelmaking using tundish refractory according to any one of claims 1 to 5, wherein the steel grades in converter steelmaking are HRB400E and HRB 500E.

Technical Field

The invention belongs to the technical field of steel making, and relates to a method for converter steelmaking slagging by using tundish refractory.

Background

Slagging is an important operation in converter steelmaking. The purpose of slagging is to rapidly form slag, so that the slag has certain alkalinity, and impurities such as sulfur, phosphorus and the like in the slag are removed to the range required by the steel grade as soon as possible. By controlling the adding type, adding amount and adding time of the slag charge, the slag has certain alkalinity, oxidizability, magnesium oxide, good fluidity and the like, so that molten iron reaction in a steelmaking molten pool is met, and corrosion to the lining bricks can be reduced. Because the smelting time of the converter is short, the slag must be formed quickly so as to meet the requirements of smelting process and strengthening smelting.

The existing slagging technology uses lime, dolomite, magnesium balls and ladle slag for slagging, but the slagging materials are processed at different depths, so that the price is increased, and the steel-making processing cost is increased. Therefore, how to solve the problems of converter steelmaking slag formation and realize low-cost steelmaking slag formation is an important content which needs to be researched.

Disclosure of Invention

In order to solve the technical problems, the invention provides a converter steelmaking slagging method by using tundish refractory, which can effectively improve the content of magnesium oxide in slag, reduce the corrosion of furnace lining bricks, simultaneously contribute to earlier-stage slagging, form low-melting-point compounds, promote the desulfurization and dephosphorization of the slag, realize the recycling of the tundish waste refractory and reduce the converter steelmaking slagging cost.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

a method for converter steelmaking slagging by using tundish refractory materials is characterized in that in the converter blowing process, according to the slag reaction condition in a converter, a slagging material is added, and rapid slagging and slagging are carried out to obtain qualified molten steel; the converter converting process specifically comprises the following steps:

(1) after the converter is started to blow, adding 2-5 kg/t steel and 5-10 kg/t steel of tundish refractory material and lime into the converter, and adding 0-10 kg/t ladle slag within 2min of blowing;

(2) within 5-10 min of blowing, adding 0-5 kg/t steel, 5-15 kg/t steel and 5-10 kg/t steel of tundish refractory materials;

(3) convertingAfter 10min, the bomb is thrown for temperature measurement, if T_{Fruit of Chinese wolfberry}≥T_{Eyes of a user}+10, adding 2-10kg/t steel of tundish refractory material and 0-5 kg/t steel of lime for temperature adjustment; the T is_{Fruit of Chinese wolfberry}Measured temperature, T, for projectile throwing_{Eyes of a user}Is the target temperature of the steel-making model of the steel grade.

The method also comprises the step of adding a tundish refractory material and dolomite when the converter splashes slag, and carrying out slag regulation treatment on the slag.

When the converter splashes slag, 2-5 kg/t steel and 2-5 kg/t steel of tundish refractory material and dolomite are added.

The content of MgO in the tundish refractory material is more than or equal to 85wt%, and the granularity is 5-30 mm.

The ladle slag is the residual of the crushed and screened continuous casting ladle, the FeO content is more than or equal to 17wt%, and the granularity is 15-35 mm.

The steel grades of the converter steelmaking of the invention are HRB400E and HRB 500E.

Adopt the produced beneficial effect of above-mentioned technical scheme to lie in: (1) the waste tundish refractory materials inside the steel mill are adopted to replace part of magnesium materials, so that the waste of magnesium resources is reduced, the recycling of the waste tundish refractory materials is realized, and the cost of converter steelmaking slagging is reduced; (2) the content of MgO in the waste tundish refractory material is high, MgO in slag can be effectively improved, the corrosion of the slag to a furnace lining is reduced, and the service life of the converter is prolonged.

Detailed Description

The present invention will be described in further detail with reference to specific embodiments.

The invention adopts the waste tundish refractory material for slagging, and the method comprises the steps of selectively adding the waste tundish refractory material, lime, dolomite and ladle slag according to the slag reaction condition in a converter during the converter blowing process, rapidly melting and slagging, and removing harmful elements in molten iron to obtain qualified molten steel. After tapping, adding waste tundish refractory material crushed materials and dolomite when the converter splashes slag, and increasing the MgO content in the slag, so that the slag is hung on the furnace wall, and the corrosion of the furnace lining is reduced.

Compared with the prior art, the method adopts the waste tundish refractory material to replace part of magnesium materials, reduces the waste of magnesium resources, realizes the recycling of the waste tundish refractory material and reduces the converter steelmaking slagging cost. Meanwhile, the content of MgO in the waste tundish refractory material is high, MgO in slag can be effectively increased, the corrosion of slag on a furnace lining is reduced, and the service life of the converter is prolonged.

The main component of the waste tundish refractory crushed material is MgO, and when the MgO is added at the beginning of converting, the MgO can promote slag to form Mg-containing minerals and prevent the surface of lime from forming high-melting point compact 2 CaO. SiO₂And the shell layer promotes lime to melt, improves the MgO content of the early-stage slag and reduces the erosion degree of the early-stage acid slag. The addition of MgO in the slag can be improved in the middle stage of blowing, the dissolution of MgO in the magnesia carbon bricks into the slag is reduced, and the converter lining is protected. The MgO content in the slag is supersaturated and the slag becomes sticky after the addition in the later stage of blowing, so that the final slag can be hung on the surface of a furnace lining to form a slag protective layer, and the furnace life is favorably prolonged. And the temperature in the later stage of converting is increased too fast, when the temperature of the throwing temperature measurement and the target temperature are higher than 10 ℃, 2-10kg/t of waste tundish refractory material is added, so that the temperature in the furnace can be effectively adjusted. In the slag splashing process, the advantage of MgO in the waste tundish crushed materials is utilized, so that the slag becomes sticky, the MgO content is increased, and a furnace lining is protected.

The invention relates to a method for steelmaking and slagging by using a tundish refractory converter, which is suitable for smelting HRB400E and HRB500E steel grades, and comprises the following specific processes:

(1) conveying the prepared waste tundish refractory material, lime, dolomite and ladle slag to a high-level storage bin;

the tundish refractory material crushing material is a lining brick which is dismantled after the tundish is used, and the lining brick is directly put into a high-level bunker after being recovered, crushed and screened, wherein the crushed granularity is 5-30 mm, and the MgO content is more than or equal to 85 wt%;

the CaO content of the lime is more than or equal to 80wt%, the MgO content is more than or equal to 5wt%, and the granularity is 15-35 mm;

the content of CaO in dolomite is more than or equal to 40wt%, the content of MgO is more than or equal to 30wt%, and the granularity is 15-35 mm;

the ladle slag is the residual of the crushed and screened continuous casting ladle, the FeO content is more than or equal to 17wt%, and the granularity is 15-35 mm.

(2) In the converter converting process, the slag making materials are selectively added according to the slag reaction condition in the converter, the slag is rapidly melted and formed, harmful elements are removed, and qualified molten steel is obtained, and the specific operation is as follows:

firstly, after blowing, adding 2-5 kg/t steel and 5-10 kg/t steel of tundish refractory material and lime into a furnace at one time, and adding 0-10 kg/t ladle slag within 2min of blowing; blowing oxygen at the pressure of 0.73-0.80 Mpa and the lance position of 1.5-1.7 m, and completing slagging within 4min of blowing;

and (3) slag is quickly melted in the early stage of blowing, and slag-coating components FeO migrate to lime crystal lattices and generate low-melting-point substances to promote lime melting. MgO in the components of the refractory material of the tundish can inhibit CaO from producing high-melting-point compounds, and meanwhile, the MgO content in the early-stage slag is increased, and the corrosion of the slag on a furnace lining is reduced.

Secondly, in the blowing process for 5-10 min, observing through flame, and after furnace slag is thoroughly melted, adding 0-5 kg/t steel, 5-15 kg/t steel and 5-10 kg/t steel of tundish refractory materials in small batches for multiple times; the oxygen blowing pressure is 0.80-0.85 Mpa, and the gun position is 1.2-1.5 m;

the alkalinity of the slag is continuously improved along with the dissolution of lime in the middle period of converting, and the addition of the waste tundish crushed materials improves the MgO in the slag, so that the dissolution of MgO in the magnesia carbon bricks into the slag is reduced, and the converter lining is protected.

Thirdly, after blowing for 10min, carrying out bullet throwing temperature measurement, if T_{Fruit of Chinese wolfberry}≥T_{Eyes of a user}+10, adding 2-10kg/t steel of tundish refractory material and 0-5 kg/t steel of lime for temperature adjustment; the T is_{Fruit of Chinese wolfberry}Measured temperature, T, for projectile throwing_{Eyes of a user}Is the target temperature of the steel-making model of the steel grade. In the process, the oxygen blowing pressure is 0.86-0.90 Mpa, the lance position is less than 1.1m, the temperature in the furnace is effectively reduced, and the slag becomes sticky and sticks to the furnace wall.

(3) When the converter splashes slag, 2-5 kg/t steel and 2-5 kg/t steel of tundish refractory materials and 2-5 kg/t steel are added, slag is adjusted, the MgO content and the viscosity of the slag are adjusted, so that the slag is adhered to the furnace wall, and the service life of the converter is prolonged.

Example 1

Smelting HRB400E steel, wherein the charging amount of molten iron is 105 tons, the amount of scrap steel is 6 tons, 555kg of waste tundish refractory material and 555kg of lime are added at one time during blowing, 800kg of ladle slag is added within 2min of blowing, the oxygen blowing pressure is 0.76Mpa, the lance position is 1.6m, and the slag melting time is 3 minutes and 40 seconds. When blowing for 5 minutes, 800kg of lime is added, 300kg of waste tundish refractory material and 555kg of dolomite are added, the oxygen blowing pressure is 0.85Mpa, and the gun position is 1.4 m. The temperature in the converting furnace is 1636 ℃ after 11 minutes of converting, the temperature is 4 ℃ different from the target temperature 1640 ℃ of the steel-making model, the oxygen blowing pressure at the later stage of converting is 0.90Mpa, and the gun position is 1.1 m. The end point temperature is 1650 ℃, and the weight ratio of C in the end point molten steel is: 0.09%, S: 0.036%, P: 0.008 percent. The final slag alkalinity is 3.5, and the MgO content is 11.3%.

450kg of tundish refractory material crushed material and 245kg of dolomite are added when slag is splashed by the converter.

Example 2

Smelting HRB400E steel grade, charging molten iron 106 tons, scrap steel 8 tons, adding 300kg of waste tundish refractory material and 800kg of lime at one time during blowing, adding 1140kg of ladle slag within 2min of blowing, blowing oxygen pressure of 0.77Mpa, lance position of 1.5m, and slagging time of 3 minutes 20 seconds. When blowing for 6 minutes, 1000kg of lime and 1140kg of dolomite are added, the oxygen blowing pressure is 0.83Mpa, and the gun position is 1.3 m. The temperature in the blowing 11 minutes throwing furnace is 1658 ℃, the temperature is 18 ℃ different from the target temperature 1640 ℃ of a steel-making model, the oxygen blowing pressure at the later stage of blowing is 0.86Mpa, the gun position is 1.1m, and 500kg of crushed materials of the waste tundish and 200kg of lime are added. End point temperature 1640 ℃, end point molten steel by weight C:0.08%, S: 0.025%, P: 0.012 percent. The final slag alkalinity is 3.8, and the MgO content is 11.8%.

470kg of tundish refractory material and 228kg of dolomite are added when slag is splashed by the converter.

Example 3

Smelting HRB400E steel, charging 107 tons of molten iron and 5 tons of waste steel, adding 224kg of waste tundish refractory material and 1000kg of lime at one time during blowing, adding 950kg of ladle slag within 2min of blowing, wherein the oxygen blowing pressure is 0.79Mpa, the lance position is 1.5m, and the slag melting time is 3 minutes and 45 seconds. 560kg of lime is added when blowing is carried out for 5 minutes, 250kg of waste tundish refractory material, 750kg of dolomite, 0.84MPa of oxygen blowing pressure and 1.4m of lance position are added. The temperature in the blowing 11 minutes throwing furnace is 1660 ℃, the temperature is 20 ℃ different from the target temperature 1640 ℃ of the steel-making model, the oxygen blowing pressure at the later period of blowing is 0.88Mpa, the gun position is 1.1m, and 224kg of crushed materials of the waste tundish and 560kg of lime are added. End point temperature 1638 ℃, end point molten steel C by weight: 0.07%, S: 0.033%, P:0.018 percent. The final slag alkalinity is 3.5, and the MgO content is 11.6%.

224kg of tundish refractory material and 560kg of dolomite are added when slag is splashed by the converter.

Example 4

Smelting HRB500E steel, charging 105 tons of molten iron and 5 tons of scrap steel, adding 300kg of waste tundish refractory material and 1100kg of lime at one time during blowing, adding 300kg of ladle slag within 2min of blowing, wherein the oxygen blowing pressure is 0.73Mpa, the lance position is 1.7m, and the slag melting time is 3 minutes and 42 seconds. Within 5-10 min of blowing, 550kg of lime is added for multiple times in small batches, 550kg of waste tundish refractory material, 660kg of dolomite, 0.81MPa of oxygen blowing pressure and 1.2m of gun position are added. The temperature in the converting furnace for converting 11 minutes is 1651 ℃, the temperature is 11 ℃ different from the target temperature 1640 ℃ of the steel-making model, the oxygen blowing pressure at the later stage of converting is 0.89Mpa, the gun position is 1.0m, and 1100kg of crushed materials of the waste tundish are added. End point temperature 1635 ℃, end point molten steel weight percent C:0.08%, S: 0.025 percent and 0.020 percent of P. The final slag alkalinity is 3.8, and the MgO content is 11.2%.

When the converter splashes slag, 550kg of tundish refractory material and 300kg of dolomite are added.

Example 5

Smelting HRB500E steel, charging 105 tons of molten iron and 6 tons of scrap steel, adding 222kg of waste tundish refractory material and 1000kg of lime at one time during blowing, adding 910kg of ladle slag within 2min of blowing, wherein the oxygen blowing pressure is 0.80Mpa, the lance position is 1.6m, and the slag melting time is 3 minutes and 40 seconds. 1665kg of lime, 200kg of waste tundish refractory material, 560kg of dolomite, 0.80Mpa of oxygen blowing pressure and 1.5m of gun position are added in small batches within 5-10 min of blowing. The temperature in the blowing 11 minutes of the throwing furnace is 1646 ℃, the temperature is 6 ℃ different from the target temperature 1640 ℃ of the steel-making model, the oxygen blowing pressure at the later stage of blowing is 0.87Mpa, and the gun position is 0.8 m. The final temperature is 1630 ℃, the weight percentage of C in the final molten steel is 0.06%, S: 0.035%, P0.016%. The final slag alkalinity is 3.9, and the MgO content is 11.6%.

When the converter splashes slag, 500kg of tundish refractory material and 300kg of dolomite are added.

Example 6

Smelting HRB500E steel, charging 107 tons of molten iron and 7 tons of scrap steel, adding 300kg of waste tundish refractory material, 750kg of lime, 0.75MPa of oxygen blowing pressure, 1.6m of lance position and 3 minutes and 40 seconds of slagging time at one time during blowing. 1300kg of lime is added in small batches within 5-10 min in the blowing process, 200kg of waste tundish refractory material, 700kg of dolomite, 0.85Mpa of oxygen blowing pressure and 1.4m of gun position are added. The temperature in the blowing 11 minutes throwing furnace is 1653 ℃, the temperature is 13 ℃ different from the target temperature 1640 ℃ of a steel-making model, the oxygen blowing pressure at the later stage of blowing is 0.88Mpa, the gun position is 0.9m, 228kg of crushed materials of the waste tundish and 570kg of lime are added. End point temperature 1641 ℃, end point molten steel contains 0.09% by weight of C, S: 0.028 percent and 0.018 percent of P. The final slag alkalinity is 3.89, and the MgO content is 11.7%.

365kg of tundish refractory material and 350kg of dolomite are added when slag is splashed by the converter.

Case counting: the method has the advantages that the furnace condition and the production cost of a certain steel plant adopting the method for slagging 350 heats are counted, compared with the conventional method, the method reduces the consumption of other magnesium materials by adopting waste materials, the furnace condition is well maintained, and the furnace lining brick is not corroded during the test period. The cost can be reduced by about 125 yuan per furnace by using 350 heats in the method.