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Converter later-stage low-temperature tapping efficient dephosphorization method

A converter and low-temperature technology is applied in the field of low-temperature tapping and high-efficiency dephosphorization in the later stage of the converter. The effect of efficiency

Pending Publication Date: 2021-04-06
LIUZHOU IRON & STEEL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The traditional converter steelmaking dephosphorization process established on the basis of thermodynamics and kinetics consumes 40-60 kg of lime, 12-20 kg of lightly burned dolomite, and produces 90-120 kg of slag, and the content of FeOx in the slag is 14-25 kg. %, not only causing a large amount of production resources and energy consumption, but also generating a large amount of iron-containing solid waste discharge

Method used

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  • Converter later-stage low-temperature tapping efficient dephosphorization method
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  • Converter later-stage low-temperature tapping efficient dephosphorization method

Examples

Experimental program
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Effect test

Embodiment 1

[0031] The nominal capacity of the converter is 150t, and the loading capacity is 135t of molten iron + 35t of scrap steel. The consumption of molten iron per ton is 890kg / t, and the phosphorus content of the molten iron is 0.120%.

[0032] In the early stage of blowing, a 180cm high gun position is used - 540Nm 3 The large oxygen flow rate per hour oxidizes Si, Mn and part of iron in the slag. With the gradual increase of temperature, the lime (4800kg, 34kg / t per ton of steel) gradually dissolves, and the w(CaO) in the slag continues to rise. At this time, the slag has good thermodynamic conditions for dephosphorization, but more cold materials (scrap steel, lime, light-burned dolomite, etc.) are added in the early stage, the slag temperature is low, the slag fluidity is poor, and the dephosphorization efficiency is low.

[0033] As the oxygen blowing continues, the CO gas generated by the chemical reaction of carbon and oxygen makes the early slag easy to come out. At this t...

Embodiment 2

[0045] The low-temperature and high-efficiency dephosphorization process in the later stage of the converter is applied under different ratios of iron and steel materials into the converter (the amount of molten iron / scrap steel). The process gun position and oxygen flow are controlled so that no slag is emitted in the early stage and the carbon-oxygen reaction is stable in the middle stage (CO gas value is stable. rise) and the principle of no slag and no return to dryness in the later stage.

[0046] The amount of sinter added is added according to the requirements of furnace heat balance and end point temperature control, and the gun position and oxygen flow rate are adjusted in real time to improve the slag. The key process parameters of the specific dephosphorization example are as follows:

[0047] Table 2 Process parameters of high-efficiency dephosphorization in converter low-temperature smelting

[0048]

[0049]

[0050] Table 3 Composition of slag sample at co...

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Abstract

The invention discloses a converter later-stage low-temperature tapping efficient dephosphorization method. The method comprises the following steps that Si, Mn and part of iron in slag are oxidized by adopting high lance position and large oxygen flow in the early stage of blowing; with the continuation of oxygen blowing, CO gas generated by chemical reaction of carbon and oxygen enables the early-stage slag to be prone to emerge, the lance position is raised, and the oxygen flow is reduced; the lance position is lowered in the middle stage of blowing; in the middle and later stages of smelting, the lance position is increased for slag adjustment, a part of sinter is added in multiple batches, the dephosphorization effect of the slag is good, and meanwhile good thermodynamic and dynamic conditions are achieved; and then a sublance is put down for TSC, and in the later stage of smelting, the final TSO temperature is controlled to be 1590-1620 DEG C . According to the method, an in-furnace efficient dephosphorization production process under a converter end-point low-temperature tapping condition is provided, and by reducing tapping end-point temperature, the distribution ratio of phosphorus in slag and steel in the later stage of smelting of a converter is increased, and therefore the dephosphorization efficiency in the later stage of smelting is improved.

Description

technical field [0001] The invention belongs to the technical field of iron and steel production, and in particular relates to a method for high-efficiency dephosphorization of steel at a low temperature in the later stage of a converter. Background technique [0002] The dephosphorization reaction in steelmaking mainly occurs at the steel-slag interface. By increasing the basicity, increasing the temperature, and increasing the stirring capacity of the molten pool (top-bottom double blowing effect), the dephosphorization reactants and products can be increased in the steel slag. The diffusion coefficient at the interface increases the dephosphorization speed of the converter. [0003] At present, the existing converter dephosphorization process in China is mainly dephosphorization in the early stage of smelting. The key points of its operation are to use a low ratio of steel scrap into the furnace, and use a high lance position and high oxygen supply intensity in the early ...

Claims

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Application Information

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IPC IPC(8): C21C5/30C21C5/54C21C7/064
CPCC21C5/30C21C5/54C21C7/064
Inventor 韦瑞宝杨柳李健畅韦军尤陈利陆志坚陈永金陈立鹏常长志赵勇胡海涛
Owner LIUZHOU IRON & STEEL
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