阅读说明：本技术 半钢转炉双渣脱磷炼钢的方法 (double-slag dephosphorization and steel-making method for semisteel converter ) 是由 陈均 梁新腾 赵志强 杨森祥 李盛 杨晓东 于 2019-10-10 设计创作，主要内容包括：本发明涉及半钢转炉双渣脱磷炼钢的方法,属于炼钢技术领域。本发明解决的技术问题是现有半钢转炉双渣法炼钢脱磷效率降低,而且炼钢辅料消耗大。本发明提供转炉双渣脱磷炼钢的方法,(1)上炉留渣后加入碳质还原材料进行溅渣脱磷；(2)向炉内加入造渣材料控制初渣碱度在1.2～1.8,然后兑铁吹炼,炉内铁水温度在1350-1400℃时倒炉放渣；(3)加入造渣材料进行二次造渣吹炼,控制终渣碱度在3～4,出钢。本发明能在提高前期脱磷效率的同时,显著降低炼钢辅料消耗。(The invention relates to a method for dephosphorization and steel making of semisteel converter double slag, belonging to the technical field of steel making. The invention solves the technical problems that the dephosphorization efficiency of the existing semisteel converter double-slag steelmaking method is reduced, and the steelmaking auxiliary material consumption is large. The invention provides a converter double-slag dephosphorization and steel-making method, (1) adding carbonaceous reducing material to carry out slag splashing dephosphorization after slag is left in the converter; (2) adding a slagging material into the furnace, controlling the alkalinity of primary slag to be 1.2-1.8, then adding iron and blowing, and reversing the furnace to discharge slag when the temperature of molten iron in the furnace is 1350-1400 ℃; (3) and adding a slagging material to carry out secondary slagging blowing, controlling the alkalinity of final slag to be 3-4, and tapping. The invention can improve the early dephosphorization efficiency and obviously reduce the consumption of steelmaking auxiliary materials.)

1. The method for double-slag dephosphorization and steel-making of the semisteel converter is characterized by comprising the following steps:

(1) Adding a carbonaceous reducing material to carry out slag splashing dephosphorization after slag is left in the furnace;

(2) Adding a slagging material into the furnace, controlling the alkalinity of primary slag to be 1.2-1.8, then adding iron and blowing, and reversing the furnace to discharge slag when the temperature of molten iron in the furnace is 1350-1400 ℃;

(3) And adding a slagging material to carry out secondary slagging blowing, controlling the alkalinity of final slag to be 3-4, and tapping.

2. the method for dephosphorization and steel-making of semisteel converter by double slag according to claim 1, characterized in that: and (2) leaving 5-7 t of slag on the furnace in the step (1).

3. The method for dephosphorization and steelmaking by using semisteel converter through double slags as claimed in claim 1 or 2, which is characterized in that: the adding amount of the carbonaceous reducing material in the step (1) is 0.5-1.5kg per ton of steel.

4. The method for dephosphorization and steel-making of semisteel converter by double slag according to claim 1, characterized in that: the carbonaceous reducing material in the step (1) is an anthracite carburant or graphite-like material, and the anthracite carburant is preferably selected.

5. The method for dephosphorization and steel-making by using semisteel converter through double slag according to claim 1, characterized in that: the slag splashing dephosphorization process in the step (1) is that after a carbonaceous reducing material is added, a top-blowing oxygen lance blows nitrogen into the furnace, and the gas supply intensity is 2-4m³at t.min, simultaneously blowing nitrogen gas from the bottom, the gas supply intensity is 0.05-0.15m³T.min, and the slag splashing time is controlled to be 3-5 min.

6. the method for dephosphorization and steel-making of semisteel converter by double slag according to claim 1, characterized in that: and (3) the slagging material in the step (2) is an acidic composite slagging agent, and the addition amount of the slagging material is 4-8kg/t steel.

7. the method for dephosphorization and steel-making of semisteel converter by double slag according to claim 1, characterized in that: the temperature of molten steel is controlled to be lower than 1400 ℃ from the semi-steel adding stage to the slag tapping stage.

8. The method for dephosphorization and steel-making of semisteel converter by double slag according to claim 1, characterized in that: the blowing process in the step (2) is that the iron is added and then the furnace is blown by a gun, oxygen is blown at the top, and the air supply intensity is 2 to 3m³At/t.min, bottom blowing nitrogen, gas supply intensity of 0.08-0.2m³/t·min。

9. The method for dephosphorization and steel-making of semisteel converter by double slag according to claim 1, characterized in that: and (3) the slagging material comprises high-magnesium lime and active lime, wherein the adding amount of the high-magnesium lime is 5-9 kg/ton steel, and the adding amount of the active lime is 8-12 kg/ton steel.

10. The method for dephosphorization and steel-making of semisteel converter by double slag according to claim 1, characterized in that: the semi-steel comprises, by mass, 3.4-4.0% of C, traces of Si and Mn, not more than 0.015% of S and 0.060-0.080% of P.

Technical Field

The invention belongs to the technical field of steel making, and particularly relates to a method for double-slag dephosphorization and steel making of a semisteel converter.

Background

In order to reduce the consumption of auxiliary materials for converter smelting, most converter steelmaking enterprises adopt 'slag retention' operation, along with the continuous accumulation of the number of slag retention furnaces, the phosphorus content in steel slag is higher and higher, so that the dephosphorization efficiency of the converter is reduced, the slag amount in the converter is larger and larger, and the loss of metal materials is serious during slag dumping. Therefore, a double-slag remaining method is adopted by many enterprises. Patent CN103866077A discloses a steelmaking method of semisteel steelmaking double-slag remaining, which comprises the following steps: 1) under the condition that slag exists in a converter molten pool, adding a slagging material into the converter molten pool, blowing and slagging by top blowing oxygen, and pouring 40-80 wt% of slag A when the temperature of the converter molten pool is 1350-1450 ℃, the alkalinity of the slag is 1.4-2.5, and the total iron content in the slag is 12-16 wt%; 2) under the condition of top-blown oxygen, adding slag-forming materials into the converter molten pool again, and when the temperature of the molten pool in the converter is 1650-1690 ℃, the alkalinity of the slag is 3.3-4.2 and the total iron content in the slag is 15-28 wt% in percentage by weight, remaining slag and tapping; 3) after tapping is finished, slag splashing and furnace protection are carried out to obtain furnace slag B; wherein, in the step 1), before adding the slag-forming material, the slag existing in the converter molten pool is the whole slag B obtained in the step 3). The steel-making method can improve dephosphorization effect and reduce the phosphorus content to below 0.007 wt%. However, the continuous accumulation of phosphorus in the steel slag in the method can cause the reduction of dephosphorization efficiency, and the consumption of auxiliary materials for steel making is large.

Disclosure of Invention

The invention solves the technical problems that the dephosphorization efficiency of the existing semisteel converter double-slag steelmaking method is reduced, and the steelmaking auxiliary material consumption is large.

The technical scheme for solving the technical problems is to provide a method for dephosphorization and steel-making of semisteel converter double slag, which comprises the following steps:

(1) Adding a carbonaceous reducing material to carry out slag splashing dephosphorization after slag is left in the furnace;

(2) Adding a slagging material into the furnace, controlling the alkalinity of primary slag to be 1.2-1.8, then adding iron and blowing, and reversing the furnace to discharge slag when the temperature of molten iron in the furnace is 1350-1400 ℃;

(3) And adding a slagging material to carry out secondary slagging blowing, controlling the alkalinity of final slag to be 3-4, and tapping.

wherein, 5-7 t of slag is left in the furnace in the step (1).

Wherein, the adding amount of the carbonaceous reducing material in the step (1) is 0.5-1.5kg per ton of steel.

Wherein, the carbonaceous reducing material in the step (1) is anthracite carburant or graphite-like, and the anthracite carburant is preferred.

Wherein, the slag splashing dephosphorization process in the step (1) is to blow nitrogen into the furnace by a top-blowing oxygen lance after adding a carbonaceous reducing material, and the gas supply intensity is 2-4m³at t.min, simultaneously blowing nitrogen gas from the bottom, the gas supply intensity is 0.05-0.15m³T.min, and the slag splashing time is controlled to be 3-5 min.

Wherein the slagging material in the step (2) is an acidic composite slagging agent, and the addition amount is 4-8kg/t steel.

Wherein the blowing process in the step (2) comprises charging iron, blowing with a gun, top-blowing oxygen, and supplying air with intensity of 2-3m³At/t.min, bottom blowing nitrogen, gas supply intensity of 0.08-0.2m³/t·min。

Wherein the slagging material in the step (3) comprises high-magnesium lime and active lime, the adding amount of the high-magnesium lime is 5-9 kg/ton steel, and the adding amount of the active lime is 8-12 kg/ton steel.

Wherein, the semi-steel comprises 3.4-4.0% of C, traces of Si and Mn, less than or equal to 0.015% of S and 0.060-0.080% of P by mass fraction.

the invention has the beneficial effects that:

The converter double-slag steelmaking adopts a secondary dephosphorization mode combining the slag splashing dephosphorization with the double-slag method, can improve the early-stage dephosphorization efficiency and simultaneously obviously reduce the consumption of steelmaking auxiliary materials, realizes the dephosphorization rate of more than 75 percent before secondary slagging, and controls the consumption of the converter auxiliary materials to be less than 25 kg/ton steel.

Detailed Description

The invention provides a method for dephosphorization and steel making of semisteel converter double slag, which comprises the following specific steps:

(1) Adding a carbonaceous reducing material to carry out slag splashing dephosphorization after slag is left in the furnace;

(2) adding a slagging material into the furnace, controlling the alkalinity of primary slag to be 1.2-1.8, then adding iron and blowing, and reversing the furnace to discharge slag when the temperature of molten iron in the furnace is 1350-1400 ℃;

(3) And adding a slagging material to carry out secondary slagging blowing, controlling the alkalinity of final slag to be 3-4, and tapping.

the dephosphorization process of the invention goes through two stages, wherein the first stage is to firstly utilize the slag left in the upper furnace to carry out slag splashing operation, and the slag splashing process carries out dephosphorization treatment on the slag, and the process is to reduce the phosphorus content in the slag, increase the phosphorus capacity of the slag and further improve the dephosphorization rate of the converter; the second stage is double-slag smelting after slag splashing is finished.

in addition, the slag former is added before the semisteel is added to control the alkalinity of the slag, then the semisteel is added, the slag is melted and formed into slag when the semisteel is added, and then dephosphorization is carried out, so that the slag forming is faster, and the early dephosphorization effect is better.

Wherein the carbonaceous reducing material is an anthracite carburant or graphite-like material. Besides removing slag phosphorus, the residual anthracite can also improve the semisteel heat source and promote slagging, so the anthracite carburant is preferred.

The slag splashing dephosphorization process specifically comprises the steps of adding a carbonaceous reducing material, and blowing nitrogen into the furnace by a top-blowing oxygen lance with the gas supply intensity of 2-4m³At t.min, simultaneously blowing nitrogen gas from the bottom, the gas supply intensity is 0.05-0.15m³T.min, and the slag splashing time is controlled to be 3-5 min.

Wherein the slagging material in the step (2) is an acidic composite slagging agent, does not comprise high-magnesium lime and active lime, and is added in an amount of 4-8kg/t steel.

The present invention is further illustrated by the following examples. Wherein, the active lime, the high-magnesium lime and the acidic composite slagging agent used in the embodiment are all common steelmaking auxiliary materials in the field and can be purchased through conventional channels.