阅读说明：本技术 维护炼钢转炉炉底的方法 (Method for maintaining bottom of steel converter ) 是由 李盛 冉瑞江 段超 周晓勇 李亮 姚恩学 郭勇 陈顺友 唐郁 熊超 于 2021-09-07 设计创作，主要内容包括：本发明涉及炼钢转炉维护工艺领域,尤其是一种快速在炉底形成炉渣保护层,极大减少炉底的侵蚀速度,可以减少或不补炉底,提高转炉作业效率的维护炼钢转炉炉底的方法。本发明解决其技术问题所采用的技术方案是：维护炼钢转炉炉底的方法,包括铁粒,在炼钢转炉溅渣处理临近结束时,加入所述铁粒,并利用氮气吹扫使铁粒均匀铺洒在炉底炉渣表面并静置至少5分钟。本发明尤其适用于炼钢转炉炉底维护工艺之中。(The invention relates to the field of maintenance processes of steelmaking converters, in particular to a method for maintaining the bottom of a steelmaking converter, which can quickly form a slag protective layer on the bottom of the converter, greatly reduce the erosion rate of the bottom of the converter, reduce or not supplement the bottom of the converter and improve the operation efficiency of the converter. The technical scheme adopted by the invention for solving the technical problems is as follows: the method for maintaining the bottom of the steelmaking converter comprises the steps of adding iron particles when the slag splashing treatment of the steelmaking converter is nearly finished, uniformly spreading the iron particles on the surface of furnace bottom slag by utilizing nitrogen purging, and standing for at least 5 minutes. The invention is especially suitable for the maintenance process of the converter bottom of the steel converter.)

1. The method for maintaining the bottom of the steelmaking converter comprises iron particles, and is characterized in that: and adding the iron particles when the slag splashing treatment of the steel converter is nearly finished, uniformly spreading the iron particles on the surface of the furnace bottom slag by using nitrogen purging, and standing for at least 5 minutes.

2. The method of maintaining a steelmaking converter floor as recited in claim 1, wherein: the iron particles are obtained in the process of treating the primary vanadium slag.

3. The method of maintaining a steelmaking converter floor as recited in claim 2, wherein: the initial vanadium slag is obtained in the vanadium extraction treatment process of the vanadium titano-magnetite.

4. The method of maintaining a steelmaking converter floor as claimed in claim 1, 2 or 3, wherein: the iron particles comprise the following main chemical components: TFe is less than or equal to 5 percent, MFe is more than or equal to 90 percent and C is more than or equal to 3.2 percent.

5. The method of maintaining a steelmaking converter floor as claimed in claim 1, 2 or 3, wherein: the time when the slag splashing treatment of the steelmaking converter is about to finish is 3/4 times of the total slag splashing time length.

6. The method of maintaining a steelmaking converter floor as claimed in claim 1, 2 or 3, wherein: and before the iron particles are added, lifting the height of a slag splashing gun position in the converter to 5-7 m.

7. The method of maintaining a steelmaking converter floor as claimed in claim 1, 2 or 3, wherein: and firstly, filling iron particles obtained in the process of treating the primary vanadium slag into a storage bin of a converter auxiliary material for later use.

Technical Field

The invention relates to the field of maintenance processes of steelmaking converters, in particular to a method for maintaining the bottom of a steelmaking converter.

Background

The working layer of the steel-making converter lining is built by magnesia carbon bricks, the magnesia carbon bricks contain a certain amount of graphite carbon, the wettability of the graphite carbon bricks with the steel-making furnace slag is poor, and the penetration of slag into the bricks is prevented, so the service life of the magnesia carbon bricks is long. The corrosion mechanism in the converter steelmaking process is as follows: the carbon on the working surface of the magnesia carbon brick is firstly acted by oxides such as oxidizing slag TFe and the like to form a decarburized layer on the working surface of the magnesia carbon brick, the structure of the brick body is loosened and embrittled and pores are formed due to the oxidation and removal of the carbon, and the steel-making slag infiltrates and reacts with MgO to generate CaO, MgO and SiO₂、3CaO·MgO·2SiO₂、MgO·Fe₂O₃And the low-melting-point minerals fall off along with the washing of the steel slag.

At present, the domestic steel-making converters all adopt a slag splashing furnace protection process, utilize steel-making final slag (table 1) with the MgO content reaching saturation or supersaturation, form a slag splashing layer with a high melting point on the surface of a furnace lining through the blowing splashing of high-pressure nitrogen, well sinter and attach the slag splashing layer with the furnace lining, and form a solid self-consumption type refractory material layer through cooling and solidification.

TABLE 1 average composition of final slag of converter

The converter end slag component contains V with low melting point₂O₅And lithofacies analysis: 45-52 percent of tricalcium silicate, 1-1.5 percent of dicalcium silicate, 1-1.2 percent of periclase, 25-27 percent of ferrite, 9-11 percent of free CaO and 3-4 percent of RO phase. The low-melting-point ferrite in the slag has high content, and the melting temperature is 1400-1430 ℃.

The temperature of a hearth of a converter after slag splashing is 1400-1450 ℃, at such temperature, a slag splashing layer obviously cannot be completely solidified and crystallized and is only in a molten state, the slag splashing phenomenon in a slag splashing theory does not exist, a good slag splashing layer cannot be formed, under the condition of continuous steelmaking in a tight production rhythm, steel slag in the converter quickly washes the slag splashing layer in the molten state, the slag splashing layer is not anti-corrosion and cannot well protect a furnace lining, the condition of the furnace bottom is more unsatisfactory, a large amount of low-melting-point substances remain on the furnace bottom, and the corrosion of the furnace bottom is aggravated.

With the development of steel-making technology, the steel smelting grade of the converter develops towards the direction of high quality and high purity, when the steel smelting grade with ultra-low carbon and ultra-low phosphorus is smelted, the tapping temperature at the end point of the converter is high, the phosphorus content requirement is low, molten steel with strong oxidizability seriously erodes the converter lining, and the slag splashing furnace protection effect of the steel slag is not good, so that the steel slag is the main reason for influencing the increase of the furnace life of the converter. At present, each steel mill adopts a mode of feeding repairing materials to repair furnace linings. The method has strict requirements on the sintering time of the repairing materials, the sintering time is short, the repairing materials cannot be bonded with a furnace lining, the repairing effect is poor, the sintering time is long, the converter efficiency is directly influenced, and in the subsequent steelmaking process, the repairing materials cannot be prevented from falling off along with molten steel washing and melting into the molten steel, so that the quality of the molten steel is seriously influenced; the repair material maintenance adopted on the bottom of the steel-making converter can also cause the blockage of the air brick, so that the metallurgical effect of the converter is reduced; in addition, the repairing mass is expensive, which affects the cost control of the converter production. Therefore, it is necessary to adopt a new maintenance method to achieve the effect of rapid furnace repairing with extremely low cost.

Disclosure of Invention

The invention aims to solve the technical problem of providing a method for maintaining the bottom of a steelmaking converter, which can quickly form a slag protective layer on the bottom of the converter, greatly reduce the erosion speed of the bottom of the converter, reduce or not supplement the bottom of the converter and improve the operating efficiency of the converter.

The technical scheme adopted by the invention for solving the technical problems is as follows: the method for maintaining the bottom of the steelmaking converter comprises the steps of adding iron particles when the slag splashing treatment of the steelmaking converter is nearly finished, uniformly spreading the iron particles on the surface of furnace bottom slag by utilizing nitrogen purging, and standing for at least 5 minutes.

Further, the iron particles are obtained in the process of treating the primary vanadium slag.

Further, the primary vanadium slag is primary vanadium slag obtained in the vanadium extraction treatment process of the vanadium titano-magnetite.

Further, the main chemical components of the iron particles are as follows: TFe is less than or equal to 5 percent, MFe is more than or equal to 90 percent and C is more than or equal to 3.2 percent.

Further, the time period near the end of the slag splashing treatment of the steelmaking converter is 3/4 times of the total slag splashing time period.

Further, before the iron particles are added, the height of a slag splashing gun position in the converter is lifted to 5-7 m.

Further, iron particles obtained in the process of treating the primary vanadium slag are firstly filled into a storage bin of auxiliary materials of the converter for later use.

The invention has the beneficial effects that: the invention reduces the temperature of the furnace slag by absorbing physical heat by iron particles, and promotes the furnace slag of the vanadium slag at the furnace bottom to crystallize rapidly. Meanwhile, part of the iron particles absorb heat to melt, and carbon in the iron particles is dissociated and undergoes reduction reaction with iron oxide in the slag, so that ferrite is decomposed to generate high-melting-point substances, and the melting point of the slag is increased. The invention can quickly form a slag protective layer at the bottom of the converter, greatly reduce the erosion speed of the bottom of the converter, reduce or not supplement the bottom of the converter and improve the operating efficiency of the converter. The method is flexibly implemented according to the condition of the furnace bottom, the added iron particles are completely melted in the next smelting process, and the yield of molten steel can be increased, so that the steelmaking cost is reduced. The invention is especially suitable for the maintenance process of the converter bottom of the steel converter.

Detailed Description

The method for maintaining the bottom of the steelmaking converter comprises the steps of adding iron particles when the slag splashing treatment of the steelmaking converter is nearly finished, uniformly spreading the iron particles on the surface of furnace bottom slag by utilizing nitrogen purging, and standing for at least 5 minutes.

The vanadium titano-magnetite has high content of V in molten iron obtained by production, so vanadium extraction treatment is generally carried out before steel making, the product is primary vanadium slag, and a byproduct iron particle is generated in the treatment process of the primary vanadium slag. The iron particles have good physical cooling effect, and contain high carbon, so that the iron particles have certain reducibility to the steelmaking slag, and therefore, the iron particles absorb physical heat to reduce the temperature of the slag, and the slag of the furnace bottom vanadium slag is promoted to be rapidly crystallized; meanwhile, part of the iron particles absorb heat to melt, and carbon in the iron particles is dissociated and undergoes reduction reaction with iron oxide in the slag, so that ferrite is decomposed to generate high-melting-point substances, and the melting point of the slag is increased.

Generally, the primary vanadium slag is preferably the primary vanadium slag obtained in the vanadium extraction treatment process of vanadium titano-magnetite. In actual operation, in order to ensure the quality of maintenance of the converter bottom, the main chemical components of the iron particles are preferably as follows: TFe is less than or equal to 5 percent, MFe is more than or equal to 90 percent and C is more than or equal to 3.2 percent. Similarly, to ensure the accurate timing of the addition of iron particles, it is preferable that the time period near the end of the slag splashing treatment of the steelmaking converter is 3/4 times the total time period of the slag splashing. In order to prevent the slag splashing gun in the converter from being damaged when the iron particles are added, the height of the slag splashing gun in the converter is preferably raised to 5-7 m before the iron particles are added. In order to ensure sufficient iron particles, the iron particles obtained in the process of treating the primary vanadium slag are preferably firstly filled into a storage bin of a converter auxiliary material for standby.

Examples

Selecting a furnace without deep blowing or over blowing, and determining the amount of slag after steel is discharged. If slag is continuously remained, partial slag can be poured off when the slag amount is too large, the converter returns to the zero position to normally splash slag, when the slag splashing time is 3/4 of the total time, the slag splashing gun position is lifted to 5-7 m, 2-3 tons of iron particles are added, the iron particles completely enter the converter visually, the slag splashing is finished after the gun lifting, the standing is carried out for 5-10 min, scrap steel or cold materials are added, the converter is shaken before and after the slag splashing is confirmed, and then the iron and the steel are directly added.

The technical advantages of the present application will be described below by comparing the conventional mode with the mode of the present invention.

As can be seen from the comparison, the fettling rate and the fettling material consumption of the converter repairing device are obviously reduced, and the converter operating efficiency can be improved by the same workers. The application has the advantages of obvious technical advantages and wide market promotion prospect.