Molten iron pre-dephosphorization method by utilizing top and bottom combined blown converter

A technology of top-bottom re-blowing and converter, applied in the field of hot metal dephosphorization, can solve the problems of affecting slag, unfavorable dephosphorization, unfavorable temperature of slag, etc., and achieves the effect of wide source and low price

Active Publication Date: 2011-11-16
SHOUGANG CORPORATION
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, too low temperature is not conducive to slag, and reduces the dephosphorization reaction rate, and too high CaO content in slag will affect slag, which is not conducive to dephosphorization

Method used

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Examples

Experimental program
Comparison scheme
Effect test

example 1

[0023] Example 1: A 210-ton top-bottom combined blowing converter is protected by slag splashing and loaded with 20 tons of steel scrap and 216 tons of molten iron. The molten iron is C: 4.33%, Si: 0.311%, Mn: 0.18%, P: 0.084%, and T: 1353°C. Add dephosphorization agent (lime 5t, iron ore 3t and fluorite 614kg) into the converter after blowing starts. When blowing until the oxygen blowing volume reaches 35%, the position of the oxygen lance is adjusted to 2.4m, and the flow rate is adjusted to 18000Nm 3 / h, then the gun position is raised to 2.8m, and the flow rate is adjusted to about 16200Nm 3 / h. Blowing time is 479 seconds, bottom blowing N 2 The flow rate is 2966-2692Nm 3 / h. After blowing, molten iron C: 3.07%, Si: 0.010%, Mn: 0.040, P: 0.010%, T: 1325°C, dephosphorization rate 88.1%.

example 2

[0024] Example 2: After protecting the furnace with slag splashing in a 210-ton top-bottom combined blowing converter, 20 tons of scrap steel and 216 tons of molten iron were loaded. The molten iron C: 4.47%, Si: 0.406%, Mn: 0.17%, P: 0.088%, and T: 1385°C. Add dephosphorization agent (lime 9.5t, iron ore 4.5t and fluorite 850kg) into the converter after blowing starts. When blowing until the oxygen blowing volume reaches 26%, the position of the oxygen lance is adjusted to 2.4m, and the flow rate is adjusted to 18000Nm 3 / h, then the gun position is raised to 2.8m, and the flow rate is adjusted to about 16200Nm 3 / h. Blowing time is 635 seconds, bottom blowing N 2 The flow rate is 2947-3005Nm 3 / h. After blowing, molten iron C: 3.16%, Si: 0.019%, Mn: 0.11, P: 0.014%, T: 1371°C, dephosphorization rate 84.1%.

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PUM

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Abstract

The invention relates to a molten iron pre-dephosphorization method by utilizing a top and bottom combined blown converter, belonging to the technical field of molten iron pre-dephosphorization. In the method, generally used molten iron pre-dephosphorization raw and auxiliary materials, such as lime, iron ores and fluorite, are adopted; through controlling the gun position and oxygen flow of a dephosphorization oxygen gun, the fast heating at an earlier stage of smelting is achieved, the slagging effect is improved, the dephosphorization efficiency is improved to above 80%; through the oxygengun, oxygen is supplied to a molten iron bath surface from the top, and a stirred gas is supplied to the inside of molten iron through a converter bottom gas supplying system; and through controllingthe gun position and oxygen flow of the oxygen gun, the dephosphorization efficiency is improved, and the emission load of waste slag in the steel-making process is reduced.

Description

technical field [0001] The invention belongs to the technical field of molten iron dephosphorization, and in particular relates to a method for dephosphorizing molten iron by using a top-bottom double-blown converter. The dephosphorization efficiency is improved by controlling the dephosphorization oxygen lance position and oxygen flow rate. Background technique [0002] In recent years, the requirements for phosphorus content in iron and steel products have become increasingly stringent. In order to meet the requirements of steel quality, phosphorus in molten iron needs to be removed as efficiently as possible during the pretreatment stage of molten iron. Dephosphorization of molten iron is generally carried out in molten iron transport containers (such as torpedo tanks) or converters. When using a transport container for molten iron dephosphorization, due to the small upper space of the transport container, in order to avoid splashing, top slag with high alkalinity and lo...

Claims

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Application Information

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IPC IPC(8): C21C7/064
Inventor 王立峰田志宏张玮王坤孔祥涛崔阳吕迺冰
Owner SHOUGANG CORPORATION
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