CN113186369A

CN113186369A - Slag splashing furnace protection method

Info

Publication number: CN113186369A
Application number: CN202110355472.9A
Authority: CN
Inventors: 赵学强; 曹洪波; 和红杰; 韩清连; 李智刚; 阎丽珍; 霍志斌; 荣飞; 范建英
Original assignee: Xingtai Iron and Steel Co Ltd
Current assignee: Xingtai Iron and Steel Co Ltd
Priority date: 2021-04-01
Filing date: 2021-04-01
Publication date: 2021-07-30

Abstract

The invention relates to a slag splashing protection method, which is characterized in that a converter is subjected to slag splashing protection by blowing nitrogen through an oxygen lance, the distance between the oxygen lance and the bottom of the converter is controlled to be 700-1000 mm in the initial slag splashing stage, and the nitrogen pressure is controlled to be 0.85-0.95 MPa; in the slag splashing middle period, firstly lifting the oxygen lance to a position 2000-2500 mm away from the furnace bottom, and gradually reducing the lance position to a position 950-1050 mm away from the furnace bottom along with the continuation of slag splashing; and in the later slag splashing stage, the distance between the oxygen lance and the furnace bottom is 700-900 mm, the nitrogen pressure is controlled at 0.95-1.1 MPa, and the reducing agent is added at the moment to reduce FeO in the slag into Fe. The potential safety hazard caused by the adhesion of the waste steel on the converter lining is eliminated, the safety cost is realized, the one-time-reverse hit rate of the converter is improved, the production cost is reduced, and the quality of the molten steel is improved.

Description

Slag splashing furnace protection method

Technical Field

The invention belongs to the technical field of smelting of a steel metallurgical converter, and particularly relates to a slag splashing furnace protection method.

Background

A part of slag is left after tapping of the converter, an oxygen lance is used for blowing nitrogen, and the slag is splashed onto the furnace wall to achieve the purpose of furnace protection, namely slag splashing furnace protection.

After the slag splashing of the converter is finished, the high-melting-point high-magnesium oxide slag is splashed onto the wall of the converter, and a small amount of liquid high-iron oxide low-melting-point slag is left. When the converter performs the operation of low iron consumption slag retention, the ratio of the converter scrap reaches more than 20%, the contact area of the scrap and the converter lining is increased, the liquid high-iron oxide low-melting-point slag left in the converter plays a role of a binder, part of the scrap is adhered to the converter lining, and the part of the scrap cannot be melted due to the adhesion of the scrap on the converter lining in the blowing process, so that the phenomenon that the converter lining is adhered with the scrap can be generated, the molten steel level is seriously overturned when the converter is subjected to carbon pulling and converter dumping, potential safety hazards exist, the first dumping rate of the converter is influenced, the production cost is increased, and the quality of the molten steel is deteriorated.

Disclosure of Invention

The technical problem solved by the invention is as follows: the slag splashing furnace protection method is provided, and solves the problem that the converter lining is stuck with scrap steel during the process of low iron consumption of converter slag retention, thereby solving the serious phenomenon of molten steel surface turnover when the converter draws carbon and pours the converter due to the fact that the converter lining is stuck with the scrap steel, improving the first pouring hit rate of the converter, reducing the molten steel cost and improving the product quality.

In order to solve the problems, the invention provides a slag splashing furnace protection method, a converter is used for slag splashing furnace protection by blowing nitrogen through an oxygen lance,

in the initial slag splashing stage, the distance between an oxygen lance and a furnace bottom is controlled to be 700-1000 mm, and the nitrogen pressure is controlled to be 0.85-0.95 MPa;

in the slag splashing middle period, firstly lifting the oxygen lance to a position 2000-2500 mm away from the furnace bottom, and gradually reducing the lance position to a position 950-1050 mm away from the furnace bottom along with the continuation of slag splashing;

and thirdly, in the later slag splashing stage, the position of the oxygen lance is 700-900 mm away from the furnace bottom, the nitrogen pressure is controlled to be 0.95-1.1 MPa, and the reducing agent is added at the moment to reduce FeO in the slag into Fe.

Further, argon is adopted to replace nitrogen in the slag splashing furnace protection process.

Further, the reducing agent is coal powder, and the adding amount of the reducing agent is 8-12 kg/ton of furnace slag.

Further, the reducing agent is coke particles.

The adding amount of the coal powder at the later slag splashing stage is 8-12 kg/ton of furnace slag, the furnace slag is residual furnace slag in the later slag splashing stage, and the adding amount of the coal powder is 8-12 kg/ton of furnace slag, namely 8-12 kg of coal powder is added into each ton of furnace slag.

The design idea of the invention is as follows: in the initial slag splashing stage, the slag which is in high temperature and high oxidizability is mainly stirred and cooled to promote the rapid precipitation of high-melting-point substances, and part of the iron-rich slag which is in high temperature and low melting point and has strong fluidity is firstly splashed to the surface of the furnace village and is diffused into the lining brick body along the microscopic pores and cracks on the surface of the lining brick to form a sintered layer which mainly contains (MgO CaO) Fe 0. In the middle stage of slag splashing, the granular high-melting-point oxide is splashed to the surface of the sintered layer of the lining brick at the early stage of slag splashing by airflow, and the surface slag splashing layer is formed by cooling and solid solution. In the later slag splashing stage, the carbon element in the coal powder is used for reducing Fe0 in the slag, so that the melting point of the residual slag is improved, and the liquid slag is eliminated.

Adopt the produced beneficial effect of above-mentioned technical scheme to lie in: the potential safety hazard caused by the adhesion of the waste steel on the converter lining is eliminated, the safety cost is realized, the one-time-reverse hit rate of the converter is improved, the production cost is reduced, and the quality of the molten steel is improved.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Examples 1 to 6

The slag splashing protection gas can be nitrogen or other inert gas such as argon, and for cost reasons, the nitrogen is adopted in examples 1-6, and the slag splashing protection is carried out by blowing the nitrogen through the oxygen lance in the converter. The slag splashing process comprises a slag splashing initial stage, a slag splashing middle stage and a slag splashing later stage, and the distance h between oxygen at the slag splashing initial stage and the furnace bottom_{First stage}And nitrogen pressure P_{First stage}In the middle stage of slag splashing, the oxygen lance is firstly lifted to the lance position and then is at a distance h from the bottom of the furnace_{In 1}Gradually reducing the lance position along with the continuation of slag splashing, and keeping the minimum distance h between the oxygen lance and the furnace bottom in the middle period of slag splashing_{In 2}，h_{In 1}、h_{In 2}See table 1. At the later stage of slag splashing, the distance h between oxygen and the furnace bottom_{Rear end}And nitrogen pressure P_{Rear end}The reducing agent is added in the later slag splashing stage, and the type and the addition amount of the reducing agent are shown in table 1.

TABLE 1

In the examples 1 to 6, the problem that the converter lining is stuck with the scrap steel does not occur, and the phenomenon that the molten steel surface is turned over seriously when the converter pulls carbon and pours the steel into the furnace due to the fact that the converter lining is stuck with the scrap steel does not occur.

Although the present invention has been described in detail with reference to the above embodiments, it should be understood by those skilled in the art that: modifications and equivalents may be made thereto without departing from the spirit and scope of the invention and it is intended to cover in the claims the invention as defined in the appended claims.

Claims

1. A slag splashing furnace protection method, a converter is blown with nitrogen through an oxygen lance to carry out slag splashing furnace protection, which is characterized in that,

and in the later slag splashing stage, the distance between the oxygen lance and the furnace bottom is 700-900 mm, the nitrogen pressure is controlled at 0.95-1.1 MPa, and the reducing agent is added at the moment to reduce FeO in the slag into Fe.

2. The slag splashing protection method of claim 1, wherein argon is used instead of nitrogen in the slag splashing protection process.

3. The slag splashing furnace protection method according to claim 1, wherein the reducing agent is pulverized coal, and the addition amount of the reducing agent is 8-12 kg/ton of slag.

4. The slag splashing protection method of claim 1, wherein the reducing agent is coke particles.