CN116287560A

CN116287560A - Method for synchronously dephosphorizing and manganese increasing semisteel

Info

Publication number: CN116287560A
Application number: CN202211644681.6A
Authority: CN
Inventors: 陈均; 陈炼; 白旭旭; 卿德标
Original assignee: Pangang Group Panzhihua Iron and Steel Research Institute Co Ltd
Current assignee: Pangang Group Panzhihua Iron and Steel Research Institute Co Ltd
Priority date: 2022-12-20
Filing date: 2022-12-20
Publication date: 2023-06-23

Abstract

The invention discloses a method for synchronously dephosphorizing and manganese increasing semisteel, wherein manganese mineral powder is added in the semisteel production process. According to the method, a special dephosphorizing agent is not required to be added, new equipment is not required, the operation is simple, and the heat source and impact kinetic energy generated when the vanadium extracting converter produces semisteel are utilized to melt manganese ore powder, so that the double purposes of semisteel dephosphorizing and manganese increasing are achieved, and the dephosphorizing task of the steelmaking converter can be effectively relieved.

Description

Method for synchronously dephosphorizing and manganese increasing semisteel

Technical Field

The invention belongs to the technical field of metallurgy, and particularly relates to a method for synchronously dephosphorizing and manganese increasing semisteel.

Background

In a steel enterprise smelting by adopting vanadium titanomagnetite, the main raw material for converter steelmaking is semisteel obtained by extracting vanadium through a special converter, the semisteel obtained by desulfurizing vanadium-containing molten iron and extracting vanadium has the mass percent of carbon of 3.4-3.8%, the content of silicon and manganese heating slag forming elements in the semisteel are all traces, the temperature fluctuation of the semisteel is 1380-1450 ℃ when extracting vanadium, and the temperature fluctuation of the semisteel when being blended into a steelmaking converter is 1300-1350 ℃. Because the vanadium extraction process of the converter does not have dephosphorization capability, the dephosphorization task is mainly completed in the steelmaking converter. Therefore, the semisteel converter steelmaking has the problems of insufficient heat source, less heating slag forming elements, high auxiliary material consumption and the like.

Aiming at the problem of heavy dephosphorization task of semisteel converter steelmaking, literature report on relieving dephosphorization task of the steelmaking converter through semisteel dephosphorization is available. Such as a semisteel dephosphorizing agent and a semisteel dephosphorizing method in patent document CN 201310150725. The patent document provides a semisteel dephosphorizing agent and a semisteel dephosphorizing method. The dephosphorizing agent is prepared from 35-50 parts of lime, 25-45 parts of iron scale and 15-25 parts of sodium oxide by weight. The method comprises the following steps: when tapping, uniformly adding the semisteel dephosphorizing agent into the flowing molten steel, and controlling the adding amount of the semisteel dephosphorizing agent to be between 10 and 20kg/t semisteel; after tapping is completed, nitrogen is blown to the bottom of molten steel; and (5) after the nitrogen blowing is finished, slag pulling treatment is carried out. The advantages of the invention include: the dephosphorization task of the steelmaking converter when smelting molten steel can be reduced, and conditions are created for smelting low-phosphorus steel and realizing low-slag steelmaking; the phosphorus content in the semisteel can be effectively removed, the dephosphorization rate can reach more than 40%, the operation is simple, facilities and equipment are not needed to be additionally built, the working procedure time is not prolonged, and the consumption of auxiliary materials for converter steelmaking is reduced; the method can effectively avoid the problem of corrosion of the conventional dephosphorization vanadium extraction agent to the converter lining, and can reduce the sodium content in the vanadium slag.

Unlike the above patent documents, the invention adopts manganese ore to dephosphorize semisteel and increase the manganese content in semisteel, which not only reduces the phosphorus content in the steelmaking converter, but also increases the manganese content in semisteel, which is beneficial to the semisteel steelmaking converter to form slag rapidly and improves dephosphorization efficiency. No literature similar to the patent content of the invention is reported.

Disclosure of Invention

Aiming at the problems of insufficient semisteel steelmaking heat source, few heating slag forming elements and heavy dephosphorization task, the invention provides a method for synchronously dephosphorizing and manganese increasing semisteel. According to the method, the manganese ore powder is melted by utilizing the heat source and impact kinetic energy when the vanadium extracting converter produces semisteel, so that the double purposes of dephosphorizing and manganese increasing the semisteel are achieved, and the dephosphorizing task of the steelmaking converter can be effectively relieved.

A method for synchronously dephosphorizing and manganese increasing semisteel comprises the following steps of: vanadium-titanium molten iron, pretreatment and desulfurization of molten iron, vanadium extraction in a vanadium extraction converter, semisteel (manganese mineral powder is added), slag skimming and steelmaking in a steelmaking converter.

Further, the temperature of the semisteel obtained after vanadium extraction in the converter is 1380-1450 ℃.

Further, the manganese ore powder comprises the following components in percentage by weight: TMn:30% -45%, iron oxide (FexO): 15% -25%, siO2:5% -10%, caO:15% -25%, P is less than or equal to 0.050%, S is less than or equal to 0.30%, and the balance is impurities, wherein the granularity is between 100 and 200 meshes.

Further, the manganese ore powder is added in the following manner: after tapping, adding with steel flow with the addition amount of 5-8kg/t _Semisteel And (5) fully adding the steel when tapping is carried out for 1/2.

And further, after tapping, slag skimming is carried out, and dephosphorized and manganese-increased semisteel is added into a steelmaking converter for smelting.

Principle of:

and (3) manganese increase: according to the calculation of [ C ] + (MnO) = [ Mn ] +CO +.The forward reaction temperature is lower than 1200 ℃ when the carbon content of molten iron reaches more than 3.0%, the temperature of the converter when extracting the semisteel is 1380-1450 ℃, the carbon content of the semisteel is more than 3.0%, the oxygen content of the semisteel is very low, the method has the thermodynamic condition of manganese reduction in manganese ores, the reaction can completely forward progress, and the impact kinetic energy of molten steel provides stirring kinetic conditions, so that manganese in the manganese ores is reduced into the semisteel, and the purpose of semisteel manganese increase is achieved. The semisteel can be oxidized to release heat and increase chemical heat of steelmaking, and the slag is formed after oxidation to enlarge a liquid phase area of converter slag, so that rapid slag formation is promoted, and dephosphorization efficiency is improved.

Dephosphorization: the manganese mineral powder contains higher oxidizing property (FexO), the alkalinity is between 2.5 and 5, the semisteel temperature is between 1380 and 1450 ℃, and the thermodynamic conditions of low temperature, high alkalinity and high oxidizing property are provided; in addition, the impact kinetic energy of molten steel and the bubble agitation generated by the reaction [ C ] + (MnO) = [ Mn ] +CO +..

Compared with the prior art, the invention has the beneficial effects that: the method does not need to add a special dephosphorizing agent or newly added equipment, is simple to operate, and has the effect of increasing manganese of the semisteel while dephosphorizing the semisteel.

Detailed Description

The following non-limiting examples will enable those of ordinary skill in the art to more fully understand the invention and are not intended to limit the invention in any way.

Examples

The 120t converter of a certain factory adopts vanadium-titanium molten iron smelting, and the production process flow is as follows: vanadium-titanium molten iron, pretreatment and desulfurization of molten iron, vanadium extraction in a vanadium extraction converter, semisteel (manganese mineral powder is added), slag skimming and steelmaking in a steelmaking converter. The semi-steel obtained by desulfurizing vanadium-containing molten iron and extracting vanadium has the carbon mass percent of 3.4%, the silicon and manganese heating slag forming elements in the semi-steel are respectively 0.01% and 0.02%, the phosphorus content in the semi-steel is 0.078%, the temperature of the semi-steel is 1400 ℃, 800kg of manganese mineral powder (the contents of the components according to the weight percent are as follows: TMn:35%, iron oxide (FexO) 20%, siO2:8%, caO:20%, P:0.030%, S:0.12%, and the balance of impurities) is added into a semi-steel tank along with the steel flowing to the semi-steel tank when tapping begins, and the granularity is 100-200 meshes. And after tapping, slag skimming treatment is carried out on the semi-steel tank, a semi-steel sample is taken, the phosphorus content in the semi-steel is 0.040%, the manganese content in the semi-steel is 0.12%, after the dephosphorized and manganese-increased semi-steel is added into a steelmaking converter and is normally smelted, and the consumption of auxiliary materials per ton of steel is only 20kg when the phosphorus content in the final molten steel is 0.008%.

Comparative example

The 120t converter of a certain factory adopts vanadium-titanium molten iron smelting, and the production process flow is as follows: vanadium-titanium molten iron, pretreatment desulfurization of molten iron, vanadium extraction by a vanadium extraction converter, semisteel obtaining and semisteel converter steelmaking. The semi-steel obtained by desulfurizing and extracting vanadium from the vanadium-containing molten iron has the carbon mass percentage of 3.4%, the silicon and manganese heating slag-forming elements in the semi-steel are respectively 0.01% and 0.02%, the phosphorus content of the semi-steel is 0.076%, the semi-steel is normally smelted after tapping is finished at 1400 ℃, and the auxiliary material consumption of ton steel is up to 58kg when the phosphorus content of molten steel at the tapping end point is 0.009%.

Claims

1. A method for synchronously dephosphorizing and manganese increasing semisteel is characterized in that the semisteel steelmaking process flow is as follows: vanadium-titanium molten iron, pretreatment and desulfurization of molten iron, vanadium extraction by a vanadium extraction converter, semisteel production, slag skimming and steelmaking by a steelmaking converter;

and adding manganese mineral powder in the semisteel production process.

2. The method according to claim 1, wherein the semisteel obtained after vanadium extraction in the converter has a temperature of 1380-1450 ℃.

3. The method according to claim 1, wherein the manganese ore powder comprises the following components in percentage by weight: TMn:30% -45%, iron oxide (FexO): 15% -25%, siO2:5% -10%, caO:15% -25%, P is less than or equal to 0.050%, S is less than or equal to 0.30%, and the balance is impurities.

4. A method according to claim 1 or 3, wherein the manganese ore powder has a particle size of 100-200 mesh.

5. A method according to claim 1 or 3, wherein the manganese ore powder is added in the following manner: after tapping, adding with steel flow with the addition amount of 5-8kg/t _Semisteel And (5) fully adding the steel when tapping is carried out for 1/2.

6. A method according to claim 1 or 3, characterized in that slag skimming is performed after tapping is completed, and dephosphorized and manganese-increased semisteel is added into a steelmaking converter for smelting.