Less slag decarbonization refining method used in top-bottom combined blowing converter

A technology of top-bottom double blowing and converter, applied in the direction of manufacturing converters, etc., can solve the problems of prolonged smelting cycle, lime consumption and slag reduction.

Inactive Publication Date: 2012-04-25
CENT IRON & STEEL RES INST
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This kind of process prolongs the smelting cycle, but the reduction of lime consumption and slag is limited

Method used

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  • Less slag decarbonization refining method used in top-bottom combined blowing converter
  • Less slag decarbonization refining method used in top-bottom combined blowing converter
  • Less slag decarbonization refining method used in top-bottom combined blowing converter

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] The semi-steel produced by the 300t dephosphorization converter (see Table 1 for composition and temperature details) is blended into the 300t decarburization converter and then ignited and blown. In the early stage, 11.68kg / t of lime is added, 9kg / t of light burning and 1.35kg / t of fluorite are used to make slag , the composition of slag is shown in Table 2. Oxygen blowing volume 35.24Nm 3 / t, the blowing time is 11min to reach the end point (see Table 1 for the end point composition and temperature). The amount of smelting slag is 24.56kg / t, and the phosphorus distribution ratio between slag and steel is L P Reached 314.

[0034] Table 1 Metal composition in the smelting process (%)

[0035] ingredients

C

Si

S

P

mn

temperature / ℃

semi-steel

3.392

0.022

0.052

0.011

0.023

1351

end point

0.063

/

0.010

0.005

0.031

1695

[0036] Table 2 Slag...

Embodiment 2

[0039] The semi-steel produced by the 300t dephosphorization converter (see Table 3 for composition and temperature details) is blended into the 300t decarburization converter and then ignited and blown. In the early stage, 13.35kg / t of lime is added, 8.91kg / t of light burning and 0.89kg / t of ore are used to make slag , the composition of slag is shown in Table 4. Oxygen blowing volume 33.56Nm 3 / t, the blowing time is 11min to reach the end point (see Table 3 for the end point composition and temperature). The amount of smelting slag is 26.42kg / t, and the phosphorus distribution ratio between slag and steel is L P Reach 200.

[0040] Table 3 Metal composition in the smelting process (%)

[0041] ingredients

C

Si

S

P

mn

temperature / ℃

semi-steel

3.292

0.024

0.017

0.012

0.027

1310

end point

0.024

/

0.008

0.007

0.022

1656

[0042] Table 4 Slag co...

Embodiment 3

[0045] The semi-steel produced by the 300t dephosphorization converter (see Table 5 for composition and temperature details) is blended into the 300t decarburization converter and then ignited and blown. In the early stage, 14.18kg / t of lime is added, 8.94kg / t of light burning and 2.29kg / t of ore are used to make slag , the composition of slag is shown in Table 6. Oxygen blowing volume 31.72Nm 3 / t, the blowing time is 11min to reach the end point (see Table 5 for the end point composition and temperature). The amount of smelting slag is 36.15kg / t, and the phosphorus distribution ratio between slag and steel is L P Reach 235.

[0046] Table 5 Metal composition in the smelting process (%)

[0047] ingredients

C

Si

S

P

mn

temperature / ℃

semi-steel

3.317

0.017

0.026

0.008

0.029

1344

end point

0.053

/

0.008

0.006

0.020

1639

[0048] Table 6 Slag co...

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PUM

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Abstract

The invention relates to a less slag decarbonization refining method used in a top-bottom combined blowing converter. The invention belongs to the technical field of top-bottom combined blowing converter steelmaking. A steelmaking slag amount is strictly controlled, a slagging technology is modified, high-alkalinity slag with R no less than 3.5 is formed as quickly as possible, technological parameters such as steel carbon content and end point temperature are appropriately controlled, a phosphorus distribution ratio LP among the slag steel is no smaller than 200, a melting pool dephosphorization rate is maintained at a value no less than 80%, such that low-phosphorus steel with [P] no larger than 0.008% is produced. Calculated according to phosphorus balance, when semi-steel [P] is no larger than 0.03%, and end point [P] is no larger than 0.008%, the dephosphorization rate during the steelmaking procedure is no larger than 0.022%, such that the P2O5 amount is 0.5kg/t. If the slag amount is controlled at a value no larger than 30kg/t, the P2O5 content in the slag is no larger than 1.6%. When the phosphorus distribution ratio LP among the slag steel is no smaller than 200, in the steel balanced with slag, [P] is no larger than 0.008%. The method is suitable to be used in decarbonization refining of molten iron pretreated by a three-removing process in the top-bottom combined blowing converter. The method is advantaged in that: through the improvement of the converter availability, an oxygen supplying time is controlled in 11min, a smelting period is no larger than 25min, a daily smelting amount is no less than 40 times/furnace, such that a problem of insufficient decarbonization furnace heat is solved.

Description

technical field [0001] The invention belongs to the technical field of combined blowing converter steelmaking, and in particular provides a method for decarburization and refining with less slag in a top-bottom combined blowing converter. technical background [0002] In order to meet the market's large demand for high-quality clean steel, reduce the amount of converter slag and reduce the oxidation loss of iron in the slag during the blowing process, improve the dephosphorization and desulfurization effect of the slag, and ensure the stable production of low-phosphorus converters ([P]≤ 0.007%) and low-sulfur ([S]≤0.008%) clean molten steel plays an important role in realizing energy saving, environmental protection and reducing production costs in steelmaking, and is the direction for the development of steelmaking technology in the future. [0003] At present, converter steelmaking mostly uses molten iron desulfurization pretreatment as the main raw material, and adds appr...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21C5/35C21C5/36
Inventor 刘浏吴伟张丙龙魏刚阎占辉郑丛杰刘伟杨利彬朱琦
Owner CENT IRON & STEEL RES INST
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