Method for reducing the superoxidation of a bath by means of a hydrogen-containing gas and use

Abstract

The application discloses a method for reducing the over-oxidation of a molten pool by using hydrogen-containing gas and application thereof. In a converter or electric furnace smelting-LF furnace smelting process, hydrogen-containing gas is injected into the furnace to reduce the oxidation degree of the molten pool. When the converter or electric furnace reaches the smelting endpoint, hydrogen-containing gas is injected into the furnace. In the tapping process of the converter or electric furnace, hydrogen-containing gas is injected into the bottom of the ladle. In the LF furnace, hydrogen-containing gas is injected into the bottom of the ladle before the ladle enters and / or exits the station. The application can effectively reduce the over-oxidation of the molten pool of the converter, electric arc furnace and LF furnace, carry out slag modification and molten steel deoxidation, improve the yield of metal materials and reduce the production cost.

Description

Technical Field

[0001] This invention relates to the field of steelmaking technology, and more specifically, to a method and application for reducing the peroxidation of molten pool using hydrogen-containing gas. Background Technology

[0002] In the steelmaking process, oxygen blowing is used to oxidize and remove impurities from the molten steel. However, this operation can cause over-oxidation of the molten pool and lead to a large amount of iron entering the slag, resulting in iron loss. Current processes generally use solid deoxidizers, such as carbon and alloys, to modify the slag and deoxidize the molten steel. This can lead to problems such as increased carbon in the molten steel, increased costs, and increased carbon emissions. At the same time, there are also problems such as poor reaction kinetics and severe burn-off of the deoxidizer in the air.

[0003] Existing solutions include optimizing slag modification processes and equipment, and enhancing molten pool stirring. For example, Chinese patent application CN202310153088.X discloses an ultra-low carbon steel top slag modification process that rationally controls the oxidizability of ladle top slag through staged modification, achieving low-cost, low-pollution, and more precise top slag modification. Chinese patent application CN202210375840.0 discloses a method for using CO2 injection of ladle top slag modifiers, using a dedicated injection device to inject CO2 into the ladle top slag modifiers to achieve top slag modification. Chinese patent application CN202310972170.5 discloses a method for improving the modification effect of ladle slag, enhancing molten pool stirring through carbon-oxygen reaction, increasing the reaction area between ladle slag and modifier, and improving the effect of reducing slag oxidation. However, the above technologies do not involve the application of hydrogen-containing gas in the entire steel production process and lack relevant process parameters.

[0004] Another feasible approach is to directly utilize reducing gases to lower the peroxidation of the molten pool. For example, Chinese patent application CN202110542598.7 discloses a method for bottom-blown hydrogen-enhanced electric arc furnace smelting. Before tapping, bottom-blown hydrogen reduces the oxygen content of the final molten steel, improving subsequent refining efficiency. Chinese patent application CN202010717093.5 discloses a method for shortening the electric arc furnace smelting cycle by using natural gas bottom-blowing during the reduction period to improve reaction thermodynamic and kinetic conditions and shorten the smelting cycle. However, these technologies do not mention the effect of directly utilizing reducing gases on the peroxidation of the molten pool, thus failing to guide subsequent deoxidation and alloying operations. Summary of the Invention

[0005] In view of the deficiencies in the existing technology, the purpose of this invention is to provide a method and application for reducing the peroxidation of molten pool using hydrogen-containing gas. This method can effectively reduce the peroxidation of molten pools in converters, electric arc furnaces and LF furnaces, thereby improving slag quality and deoxidizing molten steel, increasing the yield of metal materials, and reducing production costs.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] The first aspect of the present invention provides a method for reducing the peroxidation of a molten pool using hydrogen-containing gas. In a converter or electric furnace smelting-LF furnace smelting process, hydrogen-containing gas is injected into the furnace to reduce the oxidation degree of the molten pool; after the converter or electric furnace reaches the smelting endpoint, hydrogen-containing gas is injected into the furnace; during the tapping process of the converter or electric furnace, hydrogen-containing gas is blown into the bottom of the ladle; in the LF furnace, before the ladle enters and / or exits the station, hydrogen-containing gas is blown into the bottom of the ladle.

[0008] Preferably, after the converter or electric furnace reaches the smelting endpoint, hydrogen-containing gas is injected using an oxygen lance and / or bottom blowing, with a blowing time of 0.1 to 3 minutes.

[0009] Preferably, during the tapping process in a converter or electric furnace, the bottom-blown hydrogen-containing gas is stirred for 0.1 to 3 minutes.

[0010] Preferably, in the LF furnace, the bottom blowing time of hydrogen-containing gas before the ladle enters and / or exits the station is 0.1 to 3 minutes.

[0011] Preferably, the hydrogen-containing gas is one or more of hydrogen, gaseous hydrocarbons, and coke oven gas, and the injection flow rate of the hydrogen-containing gas is 0.01–30 Nm³. 3 / (h·tsteel).

[0012] Preferably, no power or oxygen supply is required when injecting hydrogen-containing gas.

[0013] Preferably, after the hydrogen-containing gas is injected, the degree of oxidation of the molten pool is obtained by the following formula:

[0014]

[0015]

[0016] a=0.5·H+2·CO (3)

[0017]

[0018] Where [O]′ and [O] are the oxygen content in the steel before and after treatment, respectively, in ppm; (FeO)′ and (FeO) are the percentage contents of iron oxide in the slag before and after treatment, respectively; a is the deoxidation coefficient; b and c are empirical parameters, respectively, taken as 0.5~1.0 and 0.1~0.9; Q is the injection flow rate, in Nm³. 3 / (h·tsteel); M is the molar mass of the injected gas; d is the slag ratio; H, C, and O are the molar percentages of hydrogen, carbon, and oxygen in the hydrogen-containing gas, respectively; mslag and m steel These are the slag volume and the molten steel volume, respectively, in tons (t).

[0019] The second aspect of the present invention provides an application of the method for reducing the peroxidation of the molten pool using hydrogen-containing gas, as described in the first aspect of the present invention, in the field of steelmaking.

[0020] The method for reducing the peroxidation of molten pool using hydrogen-containing gas provided by this invention has the following effects:

[0021] 1. This invention forms an application scheme for hydrogen-containing gas in the entire steel production process by injecting hydrogen-containing gas into an over-oxidized molten metal pool to modify slag and deoxidize molten steel. It can also demonstrate the effect of the process on the oxidizability of the molten pool and guide subsequent deoxidation and alloying operations.

[0022] 2. Compared with traditional technology, this invention uses hydrogen-containing gas to replace traditional alloy deoxidizers, which solves the problem of severe burn-off of deoxidizers in air. At the same time, the stirring effect of hydrogen-containing gas entering the molten pool improves the reaction kinetics of the molten pool and reduces carbon emissions.

[0023] 3. The present invention utilizes a method for reducing the peroxidation of molten pools using hydrogen-containing gas, which can effectively reduce the peroxidation of molten pools in converters, electric arc furnaces, and LF furnaces, and has good application prospects in the steelmaking field. Detailed Implementation

[0024] To better understand the above-mentioned technical solutions of the present invention, the technical solutions of the present invention will be further described below in conjunction with embodiments.

[0025] The present invention provides a method for reducing the peroxidation of molten pool using hydrogen-containing gas. In the converter or electric furnace smelting-LF furnace smelting process, hydrogen-containing gas is injected into the furnace to reduce the oxidation degree of the molten pool, i.e., 2H + O = H2O; when the converter or electric furnace reaches the smelting endpoint, hydrogen-containing gas is injected into the furnace; during the tapping process of the converter or electric furnace, hydrogen-containing gas is blown into the bottom of the ladle; in the LF furnace, before the ladle enters and / or exits the station, hydrogen-containing gas is blown into the bottom of the ladle.

[0026] In the specific implementation plan, after the converter or electric furnace reaches the smelting endpoint, hydrogen-containing gas is injected by oxygen lance and / or bottom blowing, and the blowing time is 0.1 to 3 minutes.

[0027] In the specific implementation plan, during the tapping process of the converter or electric furnace, the bottom blowing time of the hydrogen-containing gas is 0.1 to 3 minutes.

[0028] In the specific implementation plan, in the LF furnace, before the ladle enters and / or exits the station, the bottom blowing time of hydrogen-containing gas is 0.1 to 3 minutes.

[0029] The hydrogen-containing gas is one or more of hydrogen, gaseous hydrocarbons, and coke oven gas, and the injection flow rate of the hydrogen-containing gas is 0.01–30 Nm³. 3 / (h·tsteel).

[0030] No power or oxygen supply is required when injecting hydrogen-containing gas.

[0031] After the hydrogen-containing gas is injected, the oxidation degree of the molten pool is obtained by the following formulas (1) to (4):

[0032]

[0033]

[0034] a=0.5·H+2·CO (3)

[0035]

[0036] Where [O] and [O]′ are the oxygen content in the steel before and after hydrogen gas injection, respectively, in ppm; (FeO)′ and (FeO) are the percentage contents of iron oxide in the slag before and after treatment, respectively; a is the deoxidation coefficient; b and c are empirical parameters, respectively, taken as 0.5~1.0 and 0.1~0.9; Q is the injection flow rate, in Nm³. 3 / (h·tsteel); M is the molar mass of the injected gas; d is the slag ratio; H, C, and O are the molar percentages of hydrogen, carbon, and oxygen in the hydrogen-containing gas, respectively; m slag and m steel These are the slag volume and the molten steel volume, respectively, in tons (t).

[0037] By injecting hydrogen-containing gas during the above process, slag modification and steel deoxidation are carried out, thereby reducing the oxidation degree of the molten pool. At the same time, the oxidation degree in the molten pool (i.e., the oxygen content in the steel and the iron oxide content in the slag) is obtained, which can guide the subsequent deoxidation and alloying operations, thereby reducing the deoxidizer used in deoxidation and alloying and reducing carbon emissions.

[0038] Example 1

[0039] For the smelting process of a 300t top-and-bottom combined blowing converter to a 300t LF furnace, this embodiment provides a method for reducing the peroxidation of the molten pool by blowing hydrogen-containing gas, including the following steps:

[0040] In a 300t top-and-bottom blown converter, after reaching the smelting endpoint, the oxygen content in the steel is 600 ppm, and the FeO content in the slag is 18%. An oxygen lance and bottom blowing system are used to inject hydrogen-containing gas with a composition of 30.vol% hydrogen, 30.vol% gaseous hydrocarbons, and 40.vol% coke oven gas into the furnace at a flow rate of 3500 Nm³. 3 / h, blow and stir for 0.5min; at this time, calculate according to formulas (1) and (3), where a=0.5*40%+2*40%-20%=0.8, b is 0.5, c is 0.5, M is 9.4, and thus calculate the oxygen content in the steel. The calculation is performed according to formulas (2) and (4), where d = 3 / 300 = 0.01, thus the iron oxide content in the slag is calculated.

[0041] During the converter tapping process, hydrogen-containing gas with a composition of 100.vol% coke oven gas is injected into the ladle from the bottom, stirred for 3 minutes, and the injection flow rate is 150 Nm³. 3 / h, at this time, the calculation is performed according to formulas (1) and (3), where a = 0.5 * 60% + 2 * 30% - 10% = 0.8, b is 1.0, c is 0.7, M is 10.2, and the oxygen content in the steel is... The calculation is performed according to formulas (2) and (4), where d = 1 / 300 = 0.003, and the iron oxide content in the slag is...

[0042] In a 300t LF furnace, when the ladle is fed into the station, a hydrogen-containing gas with a composition of 100.vol% hydrogen is injected into the ladle using bottom blowing, and the gas is stirred for 1 minute at a flow rate of 150 Nm³. 3 / h; At this time, the calculation is performed according to formulas (1) and (3), where a = 0.5 * 100% = 0.5, b is 0.9, c is 0.7, and M is 2. The oxygen content in the steel is calculated from this. The calculation is performed according to formulas (2) and (4), where d = 1 / 300 = 0.003, and the iron oxide content in the slag is...

[0043] Subsequently, 1.25 kg / t of aluminum granules were added to a 300t LF furnace for deoxidation and alloying until the oxygen content in the steel was 6.7 ppm.

[0044] Compared to the original process, in the method of this embodiment, the amount of aluminum granules used in the steel ladle is reduced by 0.25 kg / t during the deoxidation and alloying process, and carbon emissions are reduced by 10 kg / t.

[0045] Example 2

[0046] For a 150t electric arc furnace-150t LF furnace, this embodiment provides a method for reducing the peroxidation of the molten pool using hydrogen-containing gas, including the following steps:

[0047] In a 150t electric arc furnace, after reaching the smelting endpoint, the oxygen content in the steel is 700ppm, and the FeO content in the slag is 20%. An oxygen lance and bottom blowing are used to inject a hydrogen-containing gas with a composition of 50.vol% hydrogen and 50.vol% gaseous hydrocarbons into the furnace at a flow rate of 1800 Nm³. 3 / h, blow and stir for 1min; at this time, according to formulas (1) and (3), the oxygen content in the steel is calculated, where a = 0.5 * 80% + 2 * 20% = 0.8, b is 0.5, c is 0.5, and M is 5. The calculation is performed according to formulas (2) and (4), where d = 1.5 / 150 = 0.01, thus the iron oxide content in the slag is calculated.

[0048] During the tapping process in the electric arc furnace, a hydrogen-containing gas with a composition of 100. vol% hydrogen is injected from the bottom into the ladle, stirred for 2 minutes, and the injection flow rate is 50 Nm³. 3 / h; At this time, the calculation is performed according to formulas (1) and (3), where a = 0.5 * 100% = 0.5, b is 0.8, c is 0.6, M is 2, and the oxygen content in the steel is... The calculation is performed according to formulas (2) and (4), where d = 0.3 / 150 = 0.002, and the iron oxide content in the slag is...

[0049] Heating was carried out in a 150t LF furnace. Before leaving the station, a hydrogen-containing gas with a composition of 100.vol% hydrogen was injected into the ladle using bottom blowing for 1 minute, with a blowing flow rate of 10 Nm³. 3 / h, calculated according to formulas (1) and (3), where a = 0.5 * 100% = 0.5, b is 0.8, c is 0.4, M is 2, and the oxygen content in the steel is... The calculation is performed according to formulas (2) and (4), where d = 0.3 / 150 = 0.002, and the iron oxide content in the slag is... In subsequent processes, deoxidation and alloying are carried out by adding 0.8 kg / t of aluminum granules.

[0050] Compared to the original process, in the method of this embodiment, the amount of aluminum granules used in the steel ladle is reduced by 0.21 kg / t and carbon emissions are reduced by 12 kg / t during the deoxidation and alloying process.

[0051] Those skilled in the art should recognize that the above embodiments are merely illustrative of the present invention and are not intended to limit the present invention. Any variations or modifications to the above embodiments that are within the spirit and essence of the present invention will fall within the scope of the claims of the present invention.

Claims

1. A method for reducing the peroxidation of a molten pool using hydrogen-containing gas, characterized in that... In the converter or electric arc furnace (EAF) smelting-LF furnace process, hydrogen-containing gas is injected into the furnace to reduce the oxidation degree of the molten pool; after the converter or EAF reaches the smelting endpoint, hydrogen-containing gas is injected into the furnace; during the tapping process in the converter or EAF, hydrogen-containing gas is blown into the bottom of the ladle; in the LF furnace, hydrogen-containing gas is blown into the bottom of the ladle before it enters and / or exits the station. After injecting hydrogen-containing gas, the oxidation degree of the molten pool is obtained by the following formula: (1) (2) (3) (4) in, and These are the oxygen content in the steel before and after treatment, in ppm; and These represent the percentage content of iron oxide in the slag before and after treatment, respectively. This is the deoxygenation coefficient; c are empirical parameters, taking values ​​of 0.5–1.0 and 0.1–0.9 respectively; For the injection flow rate, Nm 3 / (h·tsteel); t is the blowing time, min; M is the molar mass of the blowing gas; What a jerk; These are the molar percentages of hydrogen, carbon, and oxygen in a hydrogen-containing gas, respectively. and These are the slag volume and the molten steel volume, in tons. The degree of oxidation in the molten pool guides subsequent deoxidation and alloying operations, thereby reducing the amount of deoxidizer used in deoxidation and alloying.

2. The method for reducing the peroxidation of the molten pool using hydrogen-containing gas according to claim 1, characterized in that, After the converter or electric furnace reaches the smelting endpoint, hydrogen-containing gas is injected using an oxygen lance and / or bottom blowing for 0.1 to 3 minutes.

3. The method for reducing the peroxidation of the molten pool using hydrogen-containing gas according to claim 2, characterized in that, During the tapping process in a converter or electric furnace, the bottom-blown hydrogen-containing gas is stirred for 0.1 to 3 minutes.

4. The method for reducing the peroxidation of the molten pool using hydrogen-containing gas according to claim 1, characterized in that, In the LF furnace, the bottom blowing time of hydrogen-containing gas before the ladle enters and / or leaves the station is 0.1 to 3 minutes.

5. The method for reducing the peroxidation of the molten pool using hydrogen-containing gas according to claim 1, characterized in that, The hydrogen-containing gas is one or more of hydrogen, gaseous hydrocarbons, and coke oven gas, and the injection flow rate of the hydrogen-containing gas is 0.01–30 Nm³. 3 / (h·tsteel).

6. The method for reducing the peroxidation of the molten pool using hydrogen-containing gas according to claim 1, characterized in that, No power or oxygen supply is required when injecting hydrogen-containing gas.

7. The application of the method for reducing the peroxidation of molten pool using hydrogen-containing gas as described in any one of claims 1 to 6 in the steelmaking field.

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