CN-121975991-A - Method and system for controlling stability of converter added high-oxidability solid waste converting

CN121975991ACN 121975991 ACN121975991 ACN 121975991ACN-121975991-A

Abstract

The application provides a method and a system for controlling the stability of blowing high-oxidability solid waste, which comprises the steps of adding high-oxidability solid waste ball pressing raw materials and molten iron into a converter molten pool, blowing oxygen into the converter molten pool by using an oxygen lance, monitoring the foaming characteristics of slag in the converter molten pool in the blowing process, lifting the oxygen lance to the outside of a converter mouth to terminate oxygen blowing when the foaming characteristics reach a preset threshold value, and immediately blowing high-pressure nitrogen into the converter molten pool through the same oxygen lance after the oxygen lance lifting is completed to form a nitrogen protective atmosphere in the converter molten pool, so that the reaction rate of carbon and ferric oxide in the slag is reduced, and foaming and splashing of the slag are inhibited. The high-oxidation solid waste safety and high-yield smelting are realized by replacing continuous oxygen supply with short-time, fixed-point and high-pressure nitrogen.

Inventors

YANG JUNFENG
HUANG GUIBIN
SUN YONGLIN
SUN LIANG
ZHU LIANG
HU WEIDONG
BI ZEYANG

Assignees

北京首钢股份有限公司

Dates

Publication Date: 20260505
Application Date: 20260126

Claims (10)

1. A method for controlling the stability of blowing of solid waste with high oxidability added to a converter, comprising the steps of: Adding high-oxidability solid waste ball pressing raw materials and molten iron into a converter molten pool; Blowing oxygen into the converter molten pool by using an oxygen lance, and blowing the high-oxidability solid waste ball pressing raw material and the molten iron; Monitoring foaming characteristics of slag in a converter molten pool in the converting process, and lifting the oxygen lance to the outside of a converter mouth when the foaming characteristics reach a preset threshold value so as to terminate oxygen injection; After the oxygen lance is lifted, high-pressure nitrogen is immediately blown into the converter molten pool through the same oxygen lance, so that a nitrogen protective atmosphere is formed in the converter molten pool, the reaction rate of carbon and ferric oxide in the slag is reduced, and foaming and splashing of the slag are inhibited; the flow rate of the high-pressure nitrogen is 44000 Nm 3 /h to 48000 Nm 3 /h, the injection gun position of the high-pressure nitrogen is controlled to be 16.5 meters to 18.5 meters from the liquid level of the converter molten pool, and the injection duration of the high-pressure nitrogen is 15 seconds to 25 seconds.
2. The method according to claim 1, wherein the charging amount of the high-oxidability solid waste pressed ball raw material is 25 tons to 30 tons and the charging amount of the molten iron is 220 tons to 230 tons.
3. The method of claim 1, wherein the oxygen is injected at a flow rate of 42000 Nm 3 /h to 46000 Nm 3 /h and at a pressure of 0.8 to MPa to 1.0 MPa.
4. The method of claim 1, wherein the preset threshold comprises any of the following: The blowing time reaches 3.5 to 4.2 minutes; Foam slag overflow occurs at the mouth of the converter; the instantaneous value of the converter internal pressure rises above 5 kPa.
5. The method according to claim 1, wherein the high pressure nitrogen injection is divided into two stages, wherein, The first stage, controlling the gun position of the high-pressure nitrogen to be 16.5 meters away from the liquid level of the converter molten pool, and blowing for 15 seconds, wherein the gun position is used for crushing a surface slag foam layer of the slag; and in the second stage, the gun position of the high-pressure nitrogen is controlled to be 17.5 meters to 18.5 meters from the liquid level of the converter molten pool, and the blowing duration is 25 seconds, so as to cool the slag.
6. The method according to claim 1, wherein the start position of the high-pressure nitrogen injection is located above the slag, and then the gun position of the high-pressure nitrogen is gradually lowered, so that the high-pressure nitrogen penetrates through the slag surface layer, and the slag breaking and cooling of the slag are synchronously realized.
7. The method according to claim 1, wherein the high-oxidability solid waste pressed ball raw material has a chemical composition of not less than 55% of total iron by mass and not less than 20% of ferrous oxide by mass.
8. The method according to claim 1, wherein the mass purity of the high-pressure nitrogen is greater than or equal to 99.9%, the temperature of the high-pressure nitrogen is room temperature, and the dew point of the high-pressure nitrogen is less than or equal to-40 ℃.
9. The method according to claim 1, characterized in that after the high-pressure nitrogen injection is finished, the oxygen lance is lowered again below the liquid level of the converter molten pool, oxygen injection is resumed, and the process of blowing the high-oxidability solid waste pressed ball raw material and the molten iron is continued to be completed until tapping.
10. A converter highly oxidative solid waste converting system for use in the method of any one of claims 1 to 9, comprising: A converter molten pool for accommodating the high-oxidability solid waste pressed ball raw material and the molten iron; the oxygen lance is arranged above the converter molten pool in a lifting manner and is used for blowing oxygen or high-pressure nitrogen into the converter molten pool; the gas switching valve group is connected with the oxygen lance and used for switching between oxygen and high-pressure nitrogen; And the control unit is connected with the gas switching valve group and the oxygen lance, and is used for controlling the oxygen lance to be lifted to the outside of the converter mouth to stop oxygen injection when the foaming characteristics of the slag reach a preset threshold value, and controlling the gas switching valve group to switch to high-pressure nitrogen so as to inject the high-pressure nitrogen into the converter molten pool through the oxygen lance.

Description

Method and system for controlling stability of converter added high-oxidability solid waste converting Technical Field The application belongs to the technical field of converter steelmaking and metallurgical solid waste recycling, and particularly relates to a method and a system for controlling the blowing stability of high-oxidability solid waste matched with a converter. Background Along with the increasingly urgent demand of recycling solid wastes in the steel industry, the high-oxidability solid wastes are rich in metal elements and chemical energy, and are regarded as high-quality raw materials for replacing iron ores and steel scraps by converters. However, the low-viscosity high-foamability slag is formed at the initial stage of 320-ton converter blowing, and the problems that the slag overflows in the furnace mouth foam within 3.5-4.2 min, the instantaneous overpressure in the furnace is more than 5 kPa, the splashing rate is increased from the conventional 5% to 25%, the metal yield is reduced by 2% -3%, environmental protection accidents are frequent and the like are also caused. The traditional splash-inhibiting means such as oxygen reduction gun, lime addition and slag pressing agent addition cannot cut off the oxygen source and inhibit the carbon-oxygen reaction rapidly due to the short reaction window (less than or equal to 10 s), which aggravates the supercooling and the rephosphorization of the converter molten pool. Disclosure of Invention The application provides a method and a system for controlling the blowing stability of high-oxidability solid waste of a converter, which aim to solve the technical problem of how to avoid incontrollable splashing of slag foam of the converter caused by high-oxidability solid waste, and the metal yield suddenly drops. In a first aspect, an embodiment of the present application provides a method for controlling stability of blowing of solid waste with high oxidability in a converter, including: Adding high-oxidability solid waste ball pressing raw materials and molten iron into a converter molten pool; Blowing oxygen into the converter molten pool by using an oxygen lance, and blowing the high-oxidability solid waste ball pressing raw material and the molten iron; Monitoring foaming characteristics of slag in a converter molten pool in the converting process, and lifting the oxygen lance to the outside of a converter mouth when the foaming characteristics reach a preset threshold value so as to terminate oxygen injection; After the oxygen lance is lifted, high-pressure nitrogen is immediately blown into the converter molten pool through the same oxygen lance, so that a nitrogen protective atmosphere is formed in the converter molten pool, the reaction rate of carbon and ferric oxide in the slag is reduced, and foaming and splashing of the slag are inhibited; The flow rate of the high-pressure nitrogen is 44000 Nm3/h to 48000 Nm3/h, the injection gun position of the high-pressure nitrogen is controlled to be 16.5 meters to 18.5 meters from the liquid level of the converter molten pool, and the injection duration of the high-pressure nitrogen is 15 seconds to 25 seconds. Optionally, the charging amount of the high-oxidability solid waste ball pressing raw material is 25 tons to 30 tons, and the charging amount of the molten iron is 220 tons to 230 tons. Optionally, the blowing flow rate of the oxygen is 42000 Nm3/h to 46000 Nm3/h, and the blowing pressure of the oxygen is 0.8 MPa to 1.0 MPa. Optionally, the preset threshold includes any one of the following cases: The blowing time reaches 3.5 to 4.2 minutes; Foam slag overflow occurs at the mouth of the converter; the instantaneous value of the converter internal pressure rises above 5 kPa. Optionally, the high pressure nitrogen injection is divided into two stages, wherein, The first stage, controlling the gun position of the high-pressure nitrogen to be 16.5 meters away from the liquid level of the converter molten pool, and blowing for 15 seconds, wherein the gun position is used for crushing a surface slag foam layer of the slag; and in the second stage, the gun position of the high-pressure nitrogen is controlled to be 17.5 meters to 18.5 meters from the liquid level of the converter molten pool, and the blowing duration is 25 seconds, so as to cool the slag. Optionally, the start position of the high-pressure nitrogen injection is located above the slag, and then the gun position of the high-pressure nitrogen is gradually lowered, so that the high-pressure nitrogen penetrates through the surface layer of the slag, and slag breaking and cooling of the slag are synchronously achieved. Optionally, the mass fraction of total iron in the chemical composition of the high-oxidability solid waste ball pressing raw material is more than or equal to 55%, and the mass fraction of ferrous oxide is more than or equal to 20%. Optionally, the mass purity of the high-pressure nitrogen is more than or equal to 99.9%