阅读说明：本技术 一种提高转炉双渣一次倒炉脱磷率的方法 (Method for improving converter double-slag once-reversing dephosphorization rate ) 是由 张胤 麻晓光 张怀军 崔弘 刁望才 王鹏飞 付海东 韩春鹏 云霞 于 2021-09-14 设计创作，主要内容包括：本发明公开了一种提高转炉双渣一次倒炉脱磷率的方法,出钢结束至溅渣护炉操作前,先进行倒渣操作,留渣总量控制在总渣量50％-70％；溅渣过程中,适当减少白云石、改性料、轻烧白云石用量,因溅渣时总渣量减少30％-50％,因此每种溅渣料的用量减少20％-30％,同时加入冶金白灰,加入量为1-2kg/t钢,改变留渣后溅渣的成分,增大留渣中自由CaO含量改善脱磷热力学条件,从而提高留渣磷分配比,提升留渣双渣一倒脱磷率。本发明的目的是提供一种提高转炉双渣一次倒炉脱磷率的方法,以解决了背景技术中转炉双渣操作一次倒炉脱磷率差的问题,改善转炉终点补吹率指标,提升钢水质量。(The invention discloses a method for improving the dephosphorization rate of a converter by double-slag once converter reversing, wherein the slag reversing operation is carried out before slag splashing and furnace protection operation after tapping, and the total amount of remaining slag is controlled to be 50-70% of the total amount of slag; in the slag splashing process, the use amounts of dolomite, modified materials and light-burned dolomite are properly reduced, the total slag amount is reduced by 30-50% when slag is splashed, so that the use amount of each slag splashing material is reduced by 20-30%, and meanwhile, metallurgical lime is added, the addition amount is 1-2kg/t steel, the slag splashing components after slag remaining are changed, the free CaO content in the remaining slag is increased, the dephosphorization thermodynamic condition is improved, the remaining slag phosphorus distribution ratio is improved, and the remaining slag double-slag one-pouring dephosphorization ratio is improved. The invention aims to provide a method for improving the dephosphorization rate of a converter by double slag and primary converter reversing, so as to solve the problem of poor dephosphorization rate of the converter by double slag operation and primary converter reversing in the background technology, improve the endpoint reblowing rate index of the converter and improve the quality of molten steel.)

1. A method for improving the dephosphorization rate of a converter by double-slag once converter reversing is characterized in that the slag reversing operation is carried out before slag splashing and furnace protection operation after tapping, and the total amount of the remained slag is controlled to be 50-70% of the total amount of the slag; in the slag splashing process, the use amounts of dolomite, a modified material and light-burned dolomite are properly reduced, and the total slag amount is reduced by 30% -50% when slag is splashed, so that the use amounts of the slag splashing material dolomite, the modified material and the light-burned dolomite are correspondingly reduced, the reduction amount is 20% -30% of the use amount of each slag splashing material, meanwhile, metallurgical lime is added, the addition amount is 1-2kg/t of steel, the slag splashing component after slag remaining is changed, the free CaO content in the remaining slag is increased, the dephosphorization thermodynamic condition is improved, the remaining slag phosphorus distribution ratio is improved, and the once-to-once dephosphorization ratio of the remaining slag and the double slag is improved.

Technical Field

The invention relates to the technical field of ferrous metallurgy, in particular to a method for improving the dephosphorization rate of a converter by double-slag once converter reversing.

Background

The double-slag smelting process utilizes the high-alkalinity decarburization slag of the previous furnace, has high free CaO content, is kept to be continuously used in the desiliconization and dephosphorization period of the next furnace, and can carry out less slag smelting by secondary blowing after the previous slag is poured out after the previous dephosphorization, thereby reducing the consumption of auxiliary materials and iron and steel materials.

The content of end-point slag (T.Fe) of a conventional smelting converter is 15-25%, the alkalinity is 2.5-4.0, the content of the T.Fe in slag in the early-stage deslagging process of converter double-slag smelting is 7-13%, and the alkalinity is generally 1.3-1.6, so that the consumption of slagging auxiliary materials such as lime and the like can be reduced, and the consumption of steel materials can be reduced.

But is limited by equipment and operation process, and the dephosphorization rate of the double-slag once converter is unstable. Directly influences the terminal dephosphorization rate of the converter. The end-point blowing rate is high and the quality of molten steel is deteriorated.

Disclosure of Invention

The invention aims to provide a method for improving the dephosphorization rate of a converter by double slag and primary converter reversing, so as to solve the problem of poor dephosphorization rate of the converter by double slag operation and primary converter reversing in the background technology, improve the endpoint reblowing rate index of the converter and improve the quality of molten steel.

Basicity is defined as the ratio of (CaO) content to (SiO2) in the slag. In the smelting process of the converter, lime is added to generate slag with proper alkalinity, so that (CaO) reacts with [ P ] in molten steel to generate (4 CaO. P2O5) with stable situation, and the slag is solidified and removed along with the slag to achieve the purpose of removing phosphorus, wherein the reaction formula is as follows:

2[P]+5(FeO)+(3-4)(CaO)＝(3-4)CaO·P2O5+5Fe

the molten high-alkalinity furnace slag retains the final slag with high temperature, high alkalinity and high oxidizability in the furnace, reduces the consumption of slagging materials, protects the furnace lining, and creates favorable conditions for double-slag slagging and dephosphorization of the next furnace. When pouring, a large amount of low alkalinity and high phosphorus slag is poured, thereby removing partial phosphorus elements in the molten iron and achieving the purpose of dephosphorization. However, along with the increase of the cumulative cycle times of the slag, the phosphorus element in the slag is enriched in a large amount, the content of free CaO is reduced, and the phosphorus distribution ratio is reduced, so that the effect of the dephosphorization rate at the early stage of the double-slag is poorer.

In order to solve the technical problems, the invention adopts the following technical scheme:

a method for improving the dephosphorization rate of a converter by double-slag once converter reversing comprises the steps of firstly carrying out slag reversing operation after tapping is finished and before slag splashing protection operation, and controlling the total amount of remaining slag to be 50-70% of the total amount of slag; in the slag splashing process, the use amounts of dolomite, a modified material and light-burned dolomite are properly reduced, and the total slag amount is reduced by 30% -50% when slag is splashed, so that the use amounts of the slag splashing material dolomite, the modified material and the light-burned dolomite are correspondingly reduced, the reduction amount is 20% -30% of the use amount of each slag splashing material, meanwhile, metallurgical lime is added, the addition amount is 1-2kg/t of steel, the slag splashing component after slag remaining is changed, the free CaO content in the remaining slag is increased, the dephosphorization thermodynamic condition is improved, the remaining slag phosphorus distribution ratio is improved, and the once-to-once dephosphorization ratio of the remaining slag and the double slag is improved.

Compared with the prior art, the invention has the beneficial technical effects that:

by adopting the method, the average alkalinity of the double-slag once-reversing slag is obviously improved, the double-slag once-reversing dephosphorization rate is improved by 5-8% at the double-slag operating temperature, the terminal phosphorus hit rate of the double-slag converter is improved by 2%, and the problem of low double-slag once-reversing dephosphorization rate is solved. Effectively reduces the production cost and improves the quality of the molten steel at the end point.

Detailed Description

So that the manner in which the above recited aspects, features and advantages of the present invention can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to the embodiments thereof which are illustrated in the appended drawings.

A method for improving the dephosphorization rate of a converter by double-slag once-reversing comprises the steps of firstly reversing slag and controlling the total amount of residual slag before slag splashing and furnace protection operation after tapping. In the slag splashing process, the metallurgical lime is added while the slag material dolomite for conventional slag splashing, the modifying material and the light-burned dolomite are used, and the adding amount of the lime is 1-2 kg/t. After normal slag splashing furnace protection operation is finished, an operator checks the solidification effect of the slag to ensure that no liquid slag exists in the furnace and then slag remaining operation is carried out. The alkalinity of the slag remained in the furnace is increased, so that the phosphorus distribution ratio of the furnace slag is improved, the thermodynamic condition of dephosphorization is improved, and the lime consumption in the smelting process is reduced by 2-2.5 kg/t.

The invention was carried out on a 150t top-bottom combined blown converter. The smelting process adopts a double-slag remaining process. The implementation process is divided into the following parts:

normal smelting operation, after the converter end point tapping operation is finished, slag pouring operation is started, and converter steelmaking operators perform slag pouring operation, wherein the slag pouring amount is 30% -50% of the total slag amount;

and after the slag pouring operation is finished, slag splashing furnace protection operation is carried out. In the slag splashing process, the using amount of slag splashing material dolomite, modified material and light-burned dolomite is reduced according to the slag splashing condition in a converter during slag splashing, the reduction amount is 20-30% of the total amount of each slag, and meanwhile, metallurgical lime is added along with the slag in the slag splashing process, and the adding amount is 1-2kg/t steel;

after the slag splashing operation is finished, reversing the furnace to observe the solidification condition of slag charge in the furnace, and directly carrying out scrap steel adding and molten iron adding operations according to a charging system under the condition of confirming no liquid slag;

and after the loading operation is finished, performing primary blowing of the next smelting double slag. When the primary converter-reversing target is reached, stopping oxygen blowing, performing double-slag primary converter-reversing deslagging operation, discharging the high-phosphorus slag in the converter, and then blowing by feeding oxygen again until smelting is finished.

The four steps are a complete double-slag smelting circulation. The blank comparison group is produced according to the original double-slag process, the slag amount is not adjusted, and the metallurgical lime is not added in the slag splashing process.

The patent test and the comparative test were carried out in a 150t converter of a steel plant, and the data are shown in the following table:

the above-described embodiments are merely illustrative of the preferred embodiments of the present invention, and do not limit the scope of the present invention, and various modifications and improvements of the technical solutions of the present invention can be made by those skilled in the art without departing from the spirit of the present invention, and the technical solutions of the present invention are within the scope of the present invention defined by the claims.