A method of bottom blowing oxygen-lime powder to improve the reduction of chromium ore

A technology of lime powder and chrome ore, which is applied in the manufacture of converters, etc., can solve the problems of hindering the melting of chrome ore, insufficient stirring of molten pool, high FeO, etc., and achieve the effects of improving utilization rate, shortening smelting cycle and reducing production cost

Active Publication Date: 2021-07-02
UNIV OF SCI & TECH BEIJING
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The traditional method of adding lime to stainless steel smelting is to put all the lime into the steelmaking molten pool in the form of lumps from the furnace mouth at the stage of adding slagging material, which leads to the high alkalinity of the slag in the early stage, which is not conducive to the melting of chromium ore, and the block In the whole smelting process, the melting speed of lime is slow and often cannot be completely melted, which reduces the utilization rate of lime and causes waste of resources.
[0004] In the stainless steel smelting process, most of the time the bottom blowing is a small flow of inert gas, resulting in insufficient stirring of the molten pool and high FeO in the slag
Low stirring intensity leads to the decomposition of MgO and Al during the melting process of chrome ore 2 o 3 etc. will cover the surface of chrome ore, forming a dense protective layer, which hinders the further melting of chrome ore
High FeO content will increase the Cr 2 o 3 The reduction temperature is not conducive to the "decarburization and chromium preservation" reaction

Method used

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  • A method of bottom blowing oxygen-lime powder to improve the reduction of chromium ore
  • A method of bottom blowing oxygen-lime powder to improve the reduction of chromium ore
  • A method of bottom blowing oxygen-lime powder to improve the reduction of chromium ore

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Embodiment 1

[0026] The invention is applied to smelting stainless steel in a 70t TSR furnace, and the smelting raw materials are molten iron, chrome ore and ferrochrome. Install 2 bottom blowing spray guns, which are symmetrically distributed on the center line of the trunnion of the furnace bottom. The carrier gas of the spray guns conveying lime powder is oxygen, and the flow rate of a single gun is 600-1200Nm 3 / h, argon gas is injected in the later stage of smelting, and the flow rate of a single gun is 400-1200Nm 3 / h, the single-gun injection rate of lime powder is 20-60kg / min, and the particle size of lime powder is 200 mesh. The injection parameters of the spray gun are as follows: figure 2 .

[0027] The specific smelting process is:

[0028] (1) 0-20 minutes after the end of feeding, during the chromium ore melting period, control the oxygen flow rate to 1200Nm 3 / h, the lime powder injection rate is 35kg / min;

[0029] (2) 20 to 35 minutes, the initial reduction period, co...

Embodiment 2

[0035] The invention is applied to smelting stainless steel mother liquid in a 150t top-bottom combined blowing converter, and the smelting raw materials are molten iron and chromium ore. Install 2 bottom blowing spray guns, which are symmetrically distributed on the center line of the trunnion of the furnace bottom. The carrier gas of the spray guns transporting lime powder is oxygen, and the flow rate of a single gun is 900-1500Nm 3 / h, argon gas is injected in the later stage of smelting, and the flow rate of a single gun is 500~1500Nm 3 / h, the single-gun injection rate of lime powder is 60-110kg / min, and the particle size of lime powder is 200 mesh. The injection parameters of the spray gun are as follows: image 3 .

[0036] The specific smelting process is:

[0037] (1) 0-20 minutes after the end of feeding, during the chrome ore melting period, control the oxygen flow rate to 1500Nm 3 / h, the lime powder injection rate is 60kg / min;

[0038] (2) 20 to 35 minutes, the...

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Abstract

The invention proposes a method for improving the reduction of chrome ore by blowing oxygen-lime powder at the bottom, which belongs to the technical field of stainless steel smelting. In the stainless steel smelting process, oxygen is used as the carrier gas, and the lime powder is blown from the bottom of the smelting furnace into the steelmaking molten pool through the spray gun. The oxygen is directly in full contact with the steelmaking molten pool, with high utilization rate and good reaction effect. The specific surface area of ​​powder is large, and the speed of slag formation is fast. Real-time adjustment of oxygen flow rate and lime powder injection rate at different smelting stages can flexibly control slag alkalinity, effectively improve molten pool agitation, accelerate the melting and reduction process of chromium ore in slag, and increase the metal yield and Lime utilization rate, shorten stainless steel smelting cycle, reduce production cost.

Description

technical field [0001] The invention mainly belongs to the technical field of stainless steel smelting, and in particular relates to a method for improving the reduction of chrome ore by blowing oxygen-lime powder at the bottom. Background technique [0002] Chromium ore is the main raw material for smelting stainless steel. It is composed of various spinel phases in different proportions, including some SiO 2 , phosphide and sulfide and other impurity components. The spinel phase mainly includes iron-chromium spinel (FeO Cr 2 o 3 ), magnesia-chrome spinel (MgO Cr 2 o 3 ) and magnesium aluminum spinel (MgO·Al 2 o 3 ), etc., which lead to the high melting point of chromium ore, which cannot be melted quickly during the smelting process, and most of them are suspended in the slag in the form of solid phase, so the reduction speed of chromium ore is slow, the stainless steel smelting cycle is long, and the metal loss rate is large. [0003] The smelting reduction of chro...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C21C5/36C21C5/34C22C33/06
CPCC21C5/005C22C33/06
Inventor 朱荣周赟魏光升董凯魏国立陈培敦李伟峰章杰王春阳朱青德任鑫
Owner UNIV OF SCI & TECH BEIJING
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