Method for removing residual antimony in medium and low carbon molten steel

Abstract

The present invention provides a method for removing residual antimony in medium-low carbon steel liquid. In this method, antimony-containing steel is melted in an inert atmosphere at a temperature of 1550-1650°C; a certain amount of calcium-silicon-aluminum refined slag is applied to the surface of the antimony-containing steel liquid for desulfurization treatment; a certain amount of aluminum particles are added for deep deoxidation treatment; then, a refining agent calcium carbide with a content of 10-50wt% of the total mass of the calcium-silicon-aluminum refined slag is added for stirring, and then slag is removed to obtain medium-low carbon steel liquid with antimony removed. This method enables the removal rate of antimony in steel to reach 30.6-46.8%, and the sulfur content can be controlled at an extremely low level. While taking into account the antimony removal efficiency and low production cost, the method is also compatible with the existing steelmaking process and steelmaking and refining operations to be carried out simultaneously; and the process is simpler and the process time is short, which is suitable for large-scale industrial application; it overcomes the technical disadvantages of the existing antimony removal process in steel liquid, such as high production cost, large iron loss, and strict equipment requirements.

Description

Technical Field

[0001] The invention relates to the technical field of steel smelting, and in particular to a method for removing residual element antimony in medium- and low-carbon molten steel. Background Art

[0002] In the process of iron and steel metallurgy, raw materials such as iron ore, ferroalloys and scrap steel, as well as some auxiliary materials, usually contain some impurity elements, which results in a large amount of impurity elements in the final smelted steel liquid. Most of these impurity elements can be removed by conventional smelting methods. However, some residual elements, such as antimony, tin, copper and arsenic, have lower oxidation potentials than iron and are difficult or even impossible to remove during the smelting process.

[0003] In recent years, as the market's requirements for steel quality continue to increase, steel companies have begun to pay more and more attention to the content of residual elements in steel products. These difficult-to-remove residual elements often have an adverse effect on the performance of steel. Antimony, as one of the more common residual elements in steel, will reduce the strength and toughness of steel and increase its high-temperature brittleness. In addition, since antimony will continue to accumulate in the smelting process as scrap steel is recycled, if the antimony in the steel is not effectively restricted and removed in time, the scrap steel resources will not be recycled and effectively utilized. By then, the overall goal of the steel industry of high-quality green development and low-carbon energy conservation will not be successfully achieved.

[0004] At present, the main method for controlling the residual element content in China is the batch dilution method. This method uses blast furnace iron, hot-pressed iron (HBI), cold / hot direct reduced iron (DRI), iron carbide and other scrap steel substitutes with low residual element content to dilute the molten steel, and effectively controls the content of residual element antimony in the molten steel by optimizing the raw material ratio, but this method does not fundamentally reduce the total amount of antimony in the molten steel. In addition, there are also methods such as the vapor pressure method and the calcium reaction method, but there are technical disadvantages such as high production cost, large iron loss, strict equipment requirements, difficult technical operation, and difficulty in industrialization, so it cannot be applied and promoted on a large scale.

[0005] The patent with publication number CN115505679A discloses a steelmaking method for removing residual element antimony in steel. This method is to quickly add pre-melted slag ≥2t after the LF furnace enters the station; after power is supplied, feed 150~200m of pure calcium wire; continue to mix slag, control the basicity of refined slag at 10~12, CaO / Al2O3=1.8~2.0, and feed pure calcium wire according to the process sample to keep [Ca] in steel ≥0.0020wt%; add 200kg of lime during the last temperature adjustment of the LF furnace, feed 200m of pure calcium wire, and soft blow out of the station into the VD furnace; the VD furnace breaks the air and feeds 150m of pure calcium wire, and then maintains the soft blowing state until it is put on the stage for pouring. The boiling point of calcium is lower than the smelting temperature and its solubility in molten steel is low. However, this method requires the entire refining process to ensure that [Ca] in the molten steel is ≥ 0.0020wt%, which results in serious calcium loss in this method. It is necessary to feed pure calcium wire into the molten steel multiple times and in large quantities, resulting in high production costs and complicated operations.

[0006] Therefore, it is necessary to design a more cost-effective and simple method to remove the residual element antimony in medium and low carbon steel liquid. Summary of the invention

[0007] In view of the defects of the above-mentioned prior art, the purpose of the present invention is to provide a method for removing residual element antimony in medium and low carbon molten steel. The residual element antimony in the medium and low carbon molten steel can be removed by adding refining agent calcium carbide to the molten steel after preliminary desulfurization and deep deoxidation treatment at a certain smelting temperature.

[0008] To achieve the above object, the present invention provides a method for removing residual antimony in medium-low carbon molten steel, comprising the following steps:

[0009] S1. Under the conditions of inert gas as protective atmosphere and predetermined smelting temperature, the antimony-containing steel is melted to obtain antimony-containing molten steel;

[0010] S2, covering the surface of the antimony-containing molten steel in step S1 with a predetermined amount of calcium-silicon-aluminum refined slag, isolating the atmosphere, and performing a preliminary desulfurization treatment; then adding a predetermined amount of aluminum particles to the antimony-containing molten steel, performing a deep deoxidation treatment, and performing a predetermined reaction time to obtain a pretreated molten steel;

[0011] S3, adding a predetermined amount of calcium carbide as a refining agent to the molten steel at a predetermined smelting temperature and stirring for a predetermined time to complete the de-antimony treatment;

[0012] S4. After the antimony removal is completed, the slag layer on the surface of the molten steel is subjected to slag removal treatment to obtain medium-low carbon molten steel with antimony removed.

[0013] Furthermore, the element composition and content of the antimony-containing molten steel in step S1 are: C: 0.02-0.25wt%, Si: 0.10-0.30wt%, Mn: 1.5-2.0wt%, P: 0.002-0.010wt%, S: 0.002-0.006wt%, Sb: 0.01-0.15wt%, O: 0.01-0.03wt%.

[0014] Furthermore, the chemical composition and weight percentage of the calcium-silicon-aluminum refining slag in step S2 are: CaO: 20-60wt%, SiO2: 4-18wt%, Al2O3: 16-60wt%; the basicity CaO / SiO2 ranges from 3 to 12, and the range of CaO / Al2O3 is 1 to 2.25; the sulfur content in the antimony-containing molten steel after preliminary desulfurization treatment is controlled at 0.002 to 0.005wt%.

[0015] Furthermore, the predetermined amount of aluminum particles in step S2 is 0.01-0.1wt% of the total mass of the antimony-containing molten steel, and the total oxygen content in the pretreated molten steel after deep deoxidation is controlled at 5-60ppm; the purity of the aluminum particles in step S2 is greater than or equal to 99wt%.

[0016] Furthermore, the predetermined amount of calcium-silicon-aluminum refined slag in step S2 is 1-10wt% of the mass of the antimony-containing molten steel.

[0017] Furthermore, in step S3, the mass of the refining agent calcium carbide accounts for 10-50wt% of the total mass of the calcium-silicon-aluminum refining slag; and the purity of the refining agent calcium carbide is greater than or equal to 99.7wt% of analytical purity.

[0018] Furthermore, the predetermined smelting temperature in step S1 and step S3 is 1550-1650°C.

[0019] Furthermore, the predetermined reaction time in step S2 is 5 to 30 minutes; and the predetermined stirring time in step S3 is 5 to 20 minutes.

[0020] Furthermore, the stirring method in step S3 includes air blowing stirring, mechanical stirring or electromagnetic stirring.

[0021] Furthermore, the inert gas in step S1 includes argon or nitrogen.

[0022] The beneficial effects of the present invention are:

[0023] 1. The method for removing residual antimony from medium- and low-carbon molten steel provided by the present invention is to add calcium carbide to the calcium-silicon-aluminum refining slag system for antimony removal. With the help of a certain smelting temperature, the calcium carbide is decomposed into calcium and carbon to increase the calcium content in the molten steel; and the calcium-silicon-aluminum slag system isolates the gas after slagging, providing a lower oxygen partial pressure for the reaction interface, and also provides a good adsorption environment for the subsequent removal of antimony removal products in the molten steel. Finally, when antimony removal is carried out, an excellent desulfurization effect is also achieved (the desulfurization rate can reach 66-97%), and at the same time, a good removal environment is provided for other residual elements that can be removed and fixed by calcium (such as tin, etc.), and the functionality is relatively strong.

[0024] 2. The method for removing residual antimony from medium and low carbon steel liquid provided by the present invention can achieve a removal rate of 30.6-46.8% for residual antimony in steel, and the sulfur content can be controlled at an extremely low level. While taking into account both the antimony removal efficiency and low production cost, the method can also be compatible with the existing steelmaking process and steelmaking and refining operations to be carried out simultaneously. In addition, the process becomes simpler and more controllable, with a shorter process time, and is suitable for large-scale industrial applications; it overcomes the technical disadvantages of various existing processes for removing antimony from molten steel, such as high production cost, large iron loss, stringent equipment requirements, high technical operation difficulty, and difficulty in industrialization. BRIEF DESCRIPTION OF THE DRAWINGS DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is described in detail below in conjunction with specific embodiments.

[0026] In addition, it should be noted that the terms "comprises", "includes" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or apparatus.

[0027] The present invention provides a method for removing residual antimony in medium-low carbon molten steel, comprising the following steps:

[0028] S1. Under the condition of using inert gas as protective atmosphere and smelting temperature of 1550-1650° C., the antimony-containing steel is melted to obtain antimony-containing molten steel;

[0029] S2, covering the surface of the antimony-containing molten steel in step S1 with a predetermined amount of calcium-silicon-aluminum refined slag, isolating the atmosphere, and performing preliminary desulfurization treatment; then adding a predetermined amount of aluminum particles to the antimony-containing molten steel, performing deep deoxidation treatment, and obtaining pretreated molten steel after a reaction time of 5 to 30 minutes; the predetermined amount of calcium-silicon-aluminum refined slag is 1 to 10 wt% of the mass of the antimony-containing molten steel; the purity of the aluminum particles is greater than or equal to 99 wt%, the predetermined amount of aluminum particles is 0.01 to 0.1 wt% of the total mass of the antimony-containing molten steel, and the total oxygen content in the pretreated molten steel after deep deoxidation is controlled to be 5 to 60 ppm;

[0030] S3, under the condition of smelting temperature of 1550-1650°C, adding a predetermined amount of refining agent calcium carbide to the molten steel and stirring for 5-20 minutes to complete the antimony removal treatment; the refining agent calcium carbide has an analytical purity greater than or equal to 99.7wt%; the mass of the refining agent calcium carbide accounts for 10-50wt% of the total mass of the calcium-silicon-aluminum refining slag;

[0031] S4. After the antimony removal is completed, the slag layer on the surface of the molten steel is subjected to slag removal treatment to obtain medium-low carbon molten steel with antimony removed.

[0032] Preferably, in this embodiment, the element composition and content in the antimony-containing molten steel in step S1 are: C: 0.02-0.25wt%, Si: 0.10-0.30wt%, Mn: 1.5-2.0wt%, P: 0.002-0.010wt%, S: 0.002-0.006wt%, Sb: 0.01-0.15wt%, O: 0.01-0.03wt%.

[0033] Preferably, in this embodiment, the chemical composition and weight percentage of the calcium-silicon-aluminum refining slag in step S2 are: CaO: 20-60wt%, SiO2: 4-18wt%, Al2O3: 16-60wt%; wherein the basicity CaO / SiO2 ranges from 3 to 12, and the range of CaO / Al2O3 is 1 to 2.25; the sulfur content in the antimony-containing molten steel after preliminary desulfurization treatment is controlled at 0.002 to 0.005wt%.

[0034] Preferably, in this embodiment, the stirring method in step S3 includes air blowing stirring, mechanical stirring or electromagnetic stirring.

[0035] Preferably, in this embodiment, the inert gas in step S1 includes argon or nitrogen.

[0036] The method for removing residual element antimony in medium and low carbon molten steel provided by the present invention is specifically described below with reference to the embodiments.

[0037] Example 1

[0038] The elements and contents in the antimony-containing molten steel used in this embodiment 1 are: C: 0.02-0.15wt%, Si: 0.10-0.30wt%, Mn: 1.5-2.0wt%, P: 0.002-0.010wt%, S: 0.002-0.006wt%, Sb: 0.01-0.15wt%, O: 0.01-0.03wt%.

[0039] This embodiment provides a method for removing residual antimony in medium-low carbon molten steel, which specifically comprises the following steps:

[0040] S1. Under the condition that argon is used as a protective atmosphere and the smelting temperature is controlled at 1550° C., the antimony-containing steel is melted to obtain antimony-containing molten steel;

[0041] S2, covering the surface of the antimony-containing molten steel in step S1 with calcium-silicon-aluminum refined slag of 5wt% of the total mass of the antimony-containing molten steel, isolating the atmosphere, and performing preliminary desulfurization treatment; then adding aluminum particles of 0.04wt% of the total mass of the antimony-containing molten steel to the antimony-containing molten steel, performing deep deoxidation treatment, and reacting for 10 minutes to obtain pretreated molten steel; the chemical composition and weight percentage of the calcium-silicon-aluminum refined slag are: CaO: 50wt%, SiO2: 10wt%, Al2O3: 40wt%; the purity of the aluminum particles is greater than 99wt%, and the total oxygen content in the pretreated molten steel after deep deoxidation is controlled at 5-60ppm;

[0042] S3, under the condition of smelting temperature of 1550°C, adding a refining agent calcium carbide of 25wt% of the total mass of the calcium-silicon-aluminum system refining slag to the molten steel and stirring for 10 minutes to complete the de-antimony treatment; the refining agent calcium carbide has an analytical purity greater than 99.7wt%;

[0043] S4. After antimony removal is completed, the slag layer on the surface of the molten steel is stripped to prevent the molten steel from returning to antimony, that is, medium-low carbon molten steel with antimony removed is obtained.

[0044] The steel sample prepared in this embodiment 1 was tested to have a deantimony rate of up to 45.8%, a carbon content increased from 0.057wt% to 0.2wt%, and a sulfur content decreased from 0.0026wt% to 0.0006wt%.

[0045] Embodiments 2 to 6

[0046] Embodiments 2 to 6 provide a method for removing residual antimony from medium and low carbon steel liquids. Compared with Embodiment 1, the difference of Embodiment 2 is only that the smelting temperatures controlled in Step S1 and Step S3 are different, and the smelting temperature controlled in Embodiment 2 is 1650°C. Compared with Embodiment 1, the difference of Embodiment 3 is only that the content of calcium-silicon-aluminum refining slag added in Step S2 is different, and the content of calcium-silicon-aluminum refining slag added in Embodiment 3 is 3wt% of the total mass of antimony-containing steel liquid. Compared with Embodiment 1, the difference of Embodiment 4 is only that the content of aluminum particles added in Step S2 is different, and the content of aluminum particles added in Embodiment 4 is 0.1wt% of the total mass of antimony-containing steel liquid. Compared with Embodiment 1, the difference of Embodiment 5 is only that the content of refining agent calcium carbide added in Step S3 is different, and the content of refining agent calcium carbide added in Embodiment 5 is 40wt% of the total mass of refining slag. Compared with Embodiment 1, the difference of Embodiment 6 is only that the stirring time in Step S3 is different, and the stirring time in Embodiment 6 is 15min. The specific components are shown in Table 1. The other experimental steps are consistent with those in Example 1 and will not be repeated here.

[0047] Comparative Examples 1 to 8

[0048] Comparative Examples 1 to 8 provide a method for removing residual antimony from medium and low carbon steel liquids. Compared with Example 1, the difference between Comparative Examples 1 and 2 is that the smelting temperatures controlled in step S1 and step S3 are different, and the smelting temperatures controlled in Comparative Examples 1 and 2 are 1510°C and 1700°C, respectively. Compared with Example 1, the difference between Comparative Example 3 is that the content of calcium-silicon-aluminum refining slag added in step S2 is different, and the content of calcium-silicon-aluminum refining slag added in Comparative Example 3 is 15wt% of the total mass of antimony-containing steel liquid. Compared with Example 1, the difference between Comparative Example 4 is that the content of aluminum particles added in step S2 is different, and the content of aluminum particles added in Comparative Example 4 is 0wt% of the total mass of antimony-containing steel liquid. Compared with Example 1, the difference between Comparative Examples 5 and 6 is that the content of refining agent calcium carbide added in step S2 is different, and the content of refining agent calcium carbide added in Comparative Examples 5 and 6 is 2wt% and 60wt% of the total mass of refining slag, respectively. Compared with Example 1, the difference between Comparative Examples 7 and 8 is only that the stirring time in step S3 is different, and the stirring time in Comparative Examples 7 and 8 is 3 minutes and 30 minutes respectively. The specific ingredients are shown in Table 1. The other experimental steps are consistent with those in Example 1 and are not repeated here.

[0049] Table 1 Process parameter settings and performance parameters of Examples 1 to 6 and Comparative Examples 1 to 8

[0050]

[0051] The experimental results of Examples 1 to 6 and Comparative Examples 1 to 8 are shown in Table 2. Comparing Examples 1 to 2 and Comparative Examples 1 to 2, it is found that within the range of 1550 to 1650°C, the higher the temperature, the faster the decomposition of calcium carbide, the better the kinetic conditions, and the better the antimony removal effect. However, too high a smelting temperature will increase the Ca-Sb equilibrium concentration in the molten steel, thereby reducing the removal rate of antimony in the molten steel. In addition, the increase in temperature will also increase the steelmaking energy consumption ratio, increase production costs, and reduce the service life of the equipment. Comparing Example 1, Example 3 and Comparative Example 3, it is found that an appropriate amount of calcium-silicon-aluminum refining slag promotes the removal of residual elemental antimony in medium and low carbon molten steel, but too much will inhibit the removal of antimony. This is because excessive refining slag means that the amount of calcium carbide added will also increase accordingly, which will lead to significant carbon increase in the molten steel, and the increase in carbon content in the molten steel is not conducive to the removal of elemental antimony. Comparative Example 1, Example 4 and Comparative Example 4: It is found that an appropriate amount of aluminum particles can not only remove the oxygen content in the molten steel, but also has a certain promoting effect on the removal of the antimony element therein, but the further increase of the aluminum content has no obvious change in the removal of the antimony content in the molten steel. Comparative Example 1, Example 5, and Comparative Examples 5-6, it is found that when the content of the refining agent calcium carbide is within 10-50wt% of the total mass of the refining slag, the higher the content of the refining agent calcium carbide, the better the removal effect of the residual element antimony in the medium and low carbon molten steel. However, when the content of the refining agent calcium carbide increases to 60wt% of the total mass of the refining slag, the removal rate of antimony in the molten steel is greatly reduced to 19.7%. The principle is that calcium carbide will decompose at the smelting temperature to generate calcium and carbon, thereby increasing the calcium content and carbon content in the molten steel. However, too much refining agent calcium carbide will cause the molten steel to increase carbon quickly and increase the oxygen partial pressure at the steel-slag interface, thereby inhibiting the decomposition of calcium carbide and lime, making it difficult for the refined slag to transfer calcium elements into the molten steel, resulting in a significant reduction in the removal effect of elemental antimony. In addition, adding too much refining agent calcium carbide will also increase the production cost. In addition, an appropriate amount of refining agent calcium carbide will also increase the carbon content in the molten steel, which is beneficial to strengthening the tensile strength and yield strength of the steel, but too high a carbon content will reduce its plasticity, cold bending performance and impact toughness. An appropriate amount of refining agent calcium carbide and calcium-silicon-aluminum refining slag can also reduce the sulfur content in the molten steel, which can effectively prevent the hot brittleness of the steel and the occurrence of surface defects, and improve the weldability and hot workability of the steel. By comparing Example 6 and Comparative Examples 7 to 8, it is found that the stirring time also has a certain influence on the removal of residual antimony in medium and low carbon molten steel. If the time is too short, the additive added to the molten steel will not have time to react, thus affecting the removal effect of antimony in the molten steel. If the stirring time is too long, the production cost will be increased, and the molten steel will also be carbonized and antimony will be returned.

[0052] Table 2 Results of Examples 1 to 6 and Comparative Examples 1 to 8

[0053]

[0054]

[0055] In summary, the present invention provides a method for removing residual antimony in medium-low carbon steel liquid. The method firstly melts the antimony-containing steel in an inert gas protective atmosphere at a temperature of 1550-1650°C; then covers the surface of the antimony-containing steel liquid with calcium-silicon-aluminum refined slag with a content of 1-10wt% of the mass of the antimony-containing steel liquid to perform a preliminary desulfurization treatment; then adds aluminum particles with a content of 0.01-0.1wt% of the total mass of the antimony-containing steel liquid to perform a deep deoxidation treatment for a predetermined time; then adds a refining agent calcium carbide with a content of 5-50wt% of the total mass of the calcium-silicon-aluminum refined slag and stirs for 5-20 minutes; finally, the slag layer on the surface of the steel liquid is slag-scraped to obtain the medium-low carbon steel liquid with antimony removed. The method for removing residual antimony from medium and low carbon steel liquid provided by the present invention can achieve a removal rate of 30.6-46.8% for residual antimony in steel, and the slag can also achieve excellent desulfurization effect (desulfurization rate can reach 66-97%) when removing antimony, and at the same time provide a good removal environment for other residual elements that can be fixed by calcium (such as tin and arsenic), and has strong functionality. In addition, while taking into account the efficiency of antimony removal and low production cost, this method can also be compatible with the existing steelmaking process and be carried out synchronously with the steelmaking and refining operation. In addition, the process becomes simpler and more controllable, the process time is short, and it is suitable for large-scale industrial application; it overcomes the technical disadvantages of various existing processes for removing antimony from molten steel, such as high production cost, large iron loss, strict equipment requirements, high technical operation difficulty, and difficulty in industrialization.

[0056] The above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention.

Claims

1. A method for removing residual antimony in medium and low carbon molten steel, characterized in that: The following steps are involved: S1. Under the conditions of inert gas as protective atmosphere and predetermined smelting temperature, the antimony-containing steel is melted to obtain antimony-containing molten steel; S2, covering the surface of the antimony-containing molten steel in step S1 with a predetermined amount of calcium-silicon-aluminum refined slag, isolating the atmosphere, and performing preliminary desulfurization treatment; then adding a predetermined amount of aluminum particles to the antimony-containing molten steel, performing deep deoxidation treatment, and obtaining pretreated molten steel after a predetermined reaction time; the chemical composition and weight percentage of the calcium-silicon-aluminum refined slag are: CaO: 20-60wt%, SiO2: 4-18wt%, Al2O3: 16-60wt%, the basicity CaO / SiO2 ranges from 3-12, and the range of CaO / Al2O3 is 1-2.25; the predetermined amount of aluminum particles is 0.01-0.1wt% of the total mass of the antimony-containing molten steel, and the predetermined reaction time is 5-30min; The sulfur content in the antimony-containing molten steel after the preliminary desulfurization treatment is controlled at 0.002-0.005 wt%; the total oxygen content in the pretreated molten steel after deep deoxidation is controlled at 5-60 ppm; S3, at a predetermined smelting temperature, adding a predetermined amount of calcium carbide as a refining agent to the molten steel and stirring for a predetermined time to complete the de-antimony treatment, wherein the predetermined stirring time is 5 to 20 minutes; S4. After the antimony removal is completed, the slag layer on the surface of the molten steel is subjected to slag removal treatment to obtain medium-low carbon molten steel with antimony removed.

2. The method for removing residual antimony in medium and low carbon molten steel according to claim 1, characterized in that: The element composition and content in the antimony-containing molten steel in step S1 are: C: 0.02~0.25wt%, Si: 0.10~0.30wt%, Mn: 1.5~2.0wt%, P: 0.002~0.010wt%, S: 0.002~0.006wt%, Sb: 0.01~0.15wt%, O: 0.01~0.03wt%.

3. The method for removing residual antimony in medium and low carbon molten steel according to claim 1, characterized in that: The purity of the aluminum particles in step S2 is greater than or equal to 99wt%.

4. The method for removing residual antimony in medium and low carbon molten steel according to claim 1, characterized in that: The predetermined amount of calcium-silicon-aluminum refined slag in step S2 is 1-10wt% of the mass of the antimony-containing molten steel.

5. The method for removing residual antimony in medium and low carbon molten steel according to claim 1, characterized in that: The mass of the refining agent calcium carbide in step S3 accounts for 10-50wt% of the total mass of the calcium-silicon-aluminum refining slag; the purity of the refining agent calcium carbide is greater than or equal to 99.7wt% analytical purity.

6. The method for removing residual antimony in medium and low carbon molten steel according to claim 1, characterized in that: The predetermined smelting temperature in step S1 and step S3 is 1550-1650°C.

7. The method for removing residual antimony in medium and low carbon molten steel according to claim 1, characterized in that: The stirring method in step S3 includes air blowing stirring, mechanical stirring or electromagnetic stirring.

8. The method for removing residual antimony in medium and low carbon molten steel according to claim 1, characterized in that: The inert gas in step S1 includes argon or nitrogen.

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