Method for smelting manganese steel

Abstract

The invention relates to a manganese steel smelting method which comprises the following steps: blowing a steelmaking raw material in a converter top-bottom combined blowing manner to obtain blown molten steel; the converter top-bottom combined blowing mode is adopted for blowing a steelmaking raw material to obtain the blown steelmaking molten steel, and the converter top-bottom combined blowing mode comprises the steps that the steelmaking raw material is subjected to first blowing, a first slagging material is added into the steelmaking raw material in the first blowing process to form slag with first alkalinity, then first deslagging treatment is conducted, and first blown steelmaking molten steel is obtained; carrying out second blowing on the first blowing molten steel, and adding a second slagging material into the first blowing molten steel in the second blowing process to obtain blowing molten steel; the temperature and the oxygen activity of the blowing molten steel are controlled, and to-be-tapped molten steel is obtained; and the molten steel to be tapped is tapped, a third slagging material is added into the tapped molten steel in the tapping process, and the molten manganese steel is obtained. The manganese content of the manganese steel provided by the invention can be less than or equal to 0.02 wt%.

Description

Technical Field

[0001] The present application relates to the technical field of steel smelting, and in particular to a method for smelting manganese steel. Background Art

[0002] Manganese is one of the most common elements in steel materials. In general steel, manganese is a beneficial element that can improve the strength of steel, reduce brittleness, and reduce the harm of sulfur. However, in some of the latest developed and produced steels, manganese is no longer a beneficial alloying element, but the lower the mass fraction of manganese in the steel, the better. With the increase of manganese mass fraction, the conductivity of steel decreases sharply, the resistivity increases accordingly, the temperature coefficient of resistance decreases, the coercive force of steel increases, the saturation magnetic induction, residual magnetic induction and magnetic permeability all decrease, and therefore, manganese is a harmful element to soft magnetic alloys. When the [Mn] content is high, inclusions are easily formed, which reduces the plasticity and toughness of the steel. Therefore, the [[Mn] content in high-purity industrial pure iron should be controlled as low as possible.

[0003] At present, most low manganese control technologies are produced through the coordinated production of multiple processes such as converter demanganeseing and refining manganese control to achieve the smelting of low manganese steel. Summary of the invention

[0004] The present application provides a method for smelting manganese steel to solve the following technical problems: providing a new method for smelting manganese steel.

[0005] In a first aspect, the present application provides a method for smelting manganese steel, the method comprising:

[0006] The steelmaking raw materials are blown by the converter top and bottom combined blowing method to obtain blown steel liquid;

[0007] The method of using a converter top and bottom combined blowing method to blow steel-making raw materials to obtain blown steel liquid comprises:

[0008] The steel-making raw materials are subjected to a first blowing process, during which a first slag-making material is added to the steel-making raw materials to form a slag with a first basicity, and then a first slag pouring process is performed to obtain a first blown steel liquid;

[0009] subjecting the first blown steel liquid to a second blown process, and adding a second slag-making material to the first blown steel liquid during the second blown process to obtain a blown steel liquid;

[0010] Controlling the temperature and oxygen activity of the blowing molten steel to obtain molten steel to be tapped;

[0011] The molten steel to be tapped is tapped, and during the tapping process, a third slag-making material is added to the tapped molten steel to obtain molten manganese steel.

[0012] Optionally, the temperature of the molten steel to be tapped is 1590° C. to 1610° C., and the oxygen activity of the molten steel to be tapped is 500 ppm to 700 ppm.

[0013] Optionally, the first alkalinity is 1.5 to 2.5.

[0014] Optionally, adding a first slag-making material to the steelmaking raw material in the first blowing process to form a slag with a first basicity includes:

[0015] In the first blowing process, a first slag-making material is added to the steel-making raw materials to form a slag with a first basicity; wherein the first slag-making material comprises: lime, limestone, light-burned dolomite and ore;

[0016] The steelmaking raw materials include molten iron, and the limestone is added before adding the molten iron, with the total amount not less than 30kg / t steel;

[0017] When the oxygen blowing ratio reaches 6%, the lime, the light-burned dolomite and the ore are added in sequence, and the amount of the ore is 10Kg / t steel to 15Kg / t steel.

[0018] Optionally, the basicity of the second slag formed by the second slag-making material is 3-4.

[0019] Optionally, adding a second slag-making material to the first blown steel liquid during the second blowing process comprises:

[0020] In the second blowing process, a second slag-making material is added to the first blowing molten steel; wherein the second slag-making material comprises lime, limestone, light-burned dolomite, a first ore and a second ore;

[0021] The lime, the limestone and the first ore are added when the oxygen blowing ratio is 25%, and the amount of the first ore is 5 kg / t steel;

[0022] The second ore is added when the oxygen blowing ratio is 56-75%, and the amount of the second ore is not less than 5Kg / t steel.

[0023] Optionally, the first blowing time is 4 min to 5 min, and / or the second blowing time is 13 min to 14 min.

[0024] Optionally, the process parameters of the converter top-bottom combined blowing method include: converter top oxygen supply intensity, converter top oxygen supply flow rate and converter bottom gas supply intensity; wherein,

[0025] The oxygen supply intensity at the top of the converter is 3.04Nm 3 / t / min~3.18Nm 3 / t / min, the oxygen flow rate at the top of the converter is 42000Nm 3 / h~45000Nm 3 / h, the gas supply intensity at the bottom of the converter is 0.05Nm 3 / t / min~0.07Nm 3 / t / min.

[0026] Optionally, the third slag-making material includes sintered lime and fluorite; wherein,

[0027] The amount of the sintered lime is 1000kg to 2000kg, and the amount of the fluorite is 100kg to 200kg.

[0028] Optionally, the method of blowing the steelmaking raw materials by using a converter top and bottom combined blowing method to obtain the blown steel liquid comprises:

[0029] The steelmaking raw materials are blown by the converter top and bottom combined blowing method, and the oxygen lance position is set according to the oxygen blowing ratio of the blowing; when the oxygen blowing ratio is 0, the corresponding oxygen lance position is 2.2m; when the oxygen blowing ratio is 50%, the corresponding oxygen lance position is 2.0m; when the oxygen blowing ratio is 70%, the corresponding oxygen lance position is 1.8m; when the oxygen blowing ratio is 80%, the corresponding oxygen lance position is 1.6m.

[0030] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0031] The smelting method of the manganese steel provided in the embodiment of the present application comprises: adopting the top and bottom combined blowing method of the converter to blow the steelmaking raw materials to obtain the blown steel liquid; the said adopting the top and bottom combined blowing method of the converter to blow the steelmaking raw materials to obtain the blown steel liquid comprises: subjecting the steelmaking raw materials to a first blowing, adding a first slag-making material to the steelmaking raw materials during the first blowing process to form a slag with a first basicity, and then performing a first slag pouring treatment to obtain a first blown steel liquid; subjecting the first blown steel liquid to a second blowing, adding a second slag-making material to the first blown steel liquid during the second blowing process to obtain the blown steel liquid; controlling the temperature and oxygen activity of the blown steel liquid to obtain the steel liquid to be tapped; tapping the steel liquid to be tapped, and adding a third slag-making material to the tapped steel liquid during the tapping process to obtain the manganese steel liquid. The steelmaking raw materials are blown by the converter top and bottom combined blowing method, so as to fully meet the requirement of rapid slag-steel interface reaction of molten steel in a short time and achieve the maximum demanganese effect; according to the thermodynamic and kinetic principles of demanganese reaction, the blowing is divided into the first blowing and the second blowing, and when manganese is fully oxidized and not reduced, the first slag-making material is added through the first slag pouring treatment to reduce the activity of (MnO) in the slag, thereby reducing the mass transfer of manganese at the slag-steel interface in the later stage of smelting to control the return of manganese; the second slag-making material is added in the second blowing to further promote the formation of slag-steel interface reaction, thereby achieving demanganese; the temperature and oxygen activity of the blown molten steel are controlled, which is conducive to obtaining molten steel with a lower manganese content; the third slag-making material is added to the molten steel after the steel is tapped in the steel tapping process to further achieve demanganese and reduce the reaction of MnO in the slag to the molten steel, and finally obtain a manganese steel molten steel with a manganese content of ≤0.02wt%. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0033] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0034] Figure 1 A schematic flow chart of a method for smelting manganese steel provided in an embodiment of the present application. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0036] Various embodiments of the present application may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be understood as a rigid limitation on the scope of the present application; therefore, the range description should be considered to have specifically disclosed all possible sub-ranges and single numerical values ​​within the range. For example, the range description from 1 to 6 should be considered to have specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which apply regardless of the range. In addition, whenever a numerical range is indicated herein, it is meant to include any cited number (fractional or integer) within the indicated range.

[0037] In this application, the terms "include", "comprises", etc. mean "including but not limited to". In this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. In this article, "and / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. A and B can be singular or plural.

[0038] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0039] In a first aspect, the present application provides a method for smelting manganese steel. Figure 1 A schematic diagram of a process for smelting manganese steel provided in an embodiment of the present application; see Figure 1 , the method comprising:

[0040] S1, using a converter top and bottom combined blowing method to blow steelmaking raw materials to obtain blown steel liquid;

[0041] The method of using a converter top and bottom combined blowing method to blow steel-making raw materials to obtain blown steel liquid comprises:

[0042] The steel-making raw materials are subjected to a first blowing process, during which a first slag-making material is added to the steel-making raw materials to form a slag with a first basicity, and then a first slag pouring process is performed to obtain a first blown steel liquid;

[0043] In the embodiment of the present application, since a steel with an extremely low manganese content is smelted, there are certain requirements for the manganese content in the steelmaking raw materials. Low-manganese scrap steel and molten iron with a low manganese content can be selected. The manganese content of the scrap steel can be less than 0.40wt%, and the manganese content of the molten iron can be less than 0.20wt%. The amount of scrap steel can be 10t to 55t.

[0044] In some embodiments, the process parameters of the converter top-bottom combined blowing method include: converter top oxygen supply intensity, converter top oxygen supply flow rate and converter bottom gas supply intensity; wherein,

[0045] The oxygen supply intensity at the top of the converter is 3.04Nm 3 / t / min~3.18Nm 3 / t / min, the oxygen flow rate at the top of the converter is 42000Nm 3 / h~45000Nm 3 / h, the gas supply intensity at the bottom of the converter is 0.05Nm 3 / t / min~0.07Nm 3 / t / min.

[0046] In the embodiment of the present application, the process parameters of the top and bottom combined blowing mode of the converter are set, and the large flow gas stirring at the top and bottom of the converter makes the slag interface reaction more sufficient and effective, achieving the ideal demanganese effect; and the top and bottom combined blowing converter blowing technology can make the thermodynamic and kinetic conditions of molten iron dephosphorization fully utilized. For example, the oxygen supply intensity at the top of the converter can be 3.04Nm 3 / t / min, 3.06Nm 3 / t / min, 3.08Nm 3 / t / min, 3.10Nm 3 / t / min, 3.12Nm 3 / t / min, 3.14Nm 3 / t / min, 3.16Nm 3 / t / min, 3.18Nm 3 / t / min, etc.; the oxygen flow rate at the top of the converter can be 42000Nm 3 / h、42500Nm 3 / h、43000Nm 3 / h、43500Nm 3 / h、44000Nm 3 / h、45000Nm3 / h, etc., the gas supply intensity at the bottom of the converter can be 0.05Nm 3 / t / min, 0.06Nm 3 / t / min, 0.07Nm 3 / t / min, etc.

[0047] In some embodiments, the first blowing time is 4 min to 5 min, and / or the second blowing time is 13 min to 14 min.

[0048] In some embodiments, the first basicity is 1.5-2.5.

[0049] In some embodiments, the step of adding a first slag-making material to the steelmaking raw material during the first blowing process to form a slag having a first basicity comprises:

[0050] In the first blowing process, a first slag-making material is added to the steel-making raw materials to form a slag with a first basicity; wherein the first slag-making material comprises: lime, limestone, light-burned dolomite and ore;

[0051] The steelmaking raw materials include molten iron, and the limestone is added before adding the molten iron, with the total amount not less than 30kg / t steel;

[0052] When the oxygen blowing ratio reaches 6%, the lime, the light-burned dolomite and the ore are added in sequence, and the amount of the ore is 10Kg / t steel to 15Kg / t steel.

[0053] In the embodiment of the present application, according to the thermodynamic and kinetic principles of the demanganese reaction, when manganese is fully oxidized and not reduced, the first slag-making material is added to pour out part of the slag through the first slag pouring process to reduce the activity of (MnO) in the slag, thereby reducing the mass transfer of manganese at the slag-steel interface in the later stage of smelting to control the return of manganese. The first blowing is the initial stage of smelting. The first slag-making material used in the early stage of smelting can quickly form slag, and the ability of slag to absorb manganese in molten iron is enhanced, which is more conducive to removing manganese from molten steel into slag, and it is convenient to pour out high manganese slag. Specifically, in the first blowing process, a first slag-making material is added to the steel-making raw materials to form a slag with a first basicity, including: adding limestone before adding to the molten iron, with a total amount of not less than 30kg / t steel, to promote the dissolution of limestone; adding lime, light-burned dolomite and ore in sequence when the oxygen blowing ratio is 6%, controlling the basicity in advance, facilitating the formation of slag, and thus facilitating the mass transfer of Mn in the steel slag, and the amount of ore is 10Kg / t~15Kg / t steel, which can increase the FeO content in the slag and facilitate the removal of manganese content in the steel liquid. Exemplarily, the first basicity can be 1.5, 1.8, 2.0, 2.3, 2.5, etc., and the time of the first blowing can be 4min, 4.5min, 5min, etc. In addition, the first slag pouring treatment is not less than 10t, and the temperature of the molten steel during the slag pouring is not higher than 1410℃.

[0054] subjecting the first blown steel liquid to a second blown process, and adding a second slag-making material to the first blown steel liquid during the second blown process to obtain a blown steel liquid;

[0055] In some embodiments, the basicity of the second slag formed by the second slag-making material is 3-4.

[0056] In some embodiments, the adding a second slag-making material to the first blown steel liquid during the second blowing process comprises:

[0057] In the second blowing process, a second slag-making material is added to the first blowing molten steel; wherein the second slag-making material comprises lime, limestone, light-burned dolomite, a first ore and a second ore;

[0058] The lime, the limestone and the first ore are added when the oxygen blowing ratio is 25%, and the amount of the first ore is 5 kg / t steel;

[0059] The second ore is added when the oxygen blowing ratio is 56-75%, and the amount of the second ore is not less than 5Kg / t steel.

[0060] In an embodiment of the present application, a second slag-making material is added to the first blowing molten steel during the second blowing process, including: adding lime, limestone, and ore when the blowing oxygen ratio is 25%, and the amount of ore is 5 kg / t steel, so as to form a new slag at a certain basicity as soon as possible, which is beneficial to the mass transfer of manganese at the slag-steel interface. Adding ore when the blowing oxygen ratio is 56% to 70%, and the amount of ore is not less than 5 kg / t, can increase the FeO content of the slag, facilitate the formation of slag-steel interface reaction, and facilitate demanganeseization. Exemplarily, the second basicity can be 3, 3.5, etc., and the time of the first blowing can be 13 min, 14 min, 15 min, 16 min, 17 min, etc.

[0061] Therefore, lime, light-burned dolomite, limestone and ore are used for slag making in the first and second blowing, and the order of adding materials, materials and timing of adding materials are specified. Different adding orders can meet better manganese removal conditions. Light-burned dolomite is used in slag making materials, which can protect the furnace lining and increase the service life of the converter while ensuring fast slag formation. Please refer to the chemical composition (wt%) of the first slag making raw material shown in Table 1.

[0062] Table 1 Composition of the first slag material (wt%)

[0063] name <![CDATA[SiO2]]> S MgO CaO Caustic Soda Light Burn 1.05 0.004 38.43 54.43 5.19 White ash 1.22 0.023 7.85 85.48 4.64 Sintered lime 1.25 0.02 7.47 84.79 5.60 limestone 0.69 0.012 4.0 50.6 44.00

[0064] S3, controlling the temperature and oxygen activity of the blowing molten steel to obtain molten steel to be tapped;

[0065] In some embodiments, the temperature of the molten steel to be tapped is 1590° C. to 1610° C., and the oxygen activity of the molten steel to be tapped is 500 ppm to 700 ppm.

[0066] In the embodiment of the present application, the temperature of the molten steel to be tapped is set to 1590°C to 1610°C, and the oxygen activity of the molten steel to be tapped is 500ppm to 700ppm; the reason is that: lower temperature and appropriate oxidizability are more conducive to obtaining a lower manganese content, too low temperature is not conducive to the next process, affecting production efficiency, and too high temperature makes it difficult to remove manganese. The strong oxidizability of the slag is also conducive to removing manganese from the molten steel, and too high terminal oxygen will seriously corrode the furnace lining. Exemplarily, the temperature of the molten steel to be tapped can be 1590°C, 1600°C, 1610°C, etc.; the oxygen activity of the molten steel to be tapped can be 500ppm, 550ppm, 600ppm, 650ppm, 700ppm, etc.

[0067] S4, tapping the molten steel to be tapped, and adding a third slag-making material to the tapped molten steel during the tapping process to obtain molten manganese steel.

[0068] In some embodiments, the third slag-making material includes sintered lime and fluorite; wherein,

[0069] The amount of the sintered lime is 1000kg to 2000kg, and the amount of the fluorite is 100kg to 200kg.

[0070] In the embodiment of the present application, the third slag-making material is added to the molten steel after the steel is tapped during the steel tapping process, which can increase the slag basicity, further promote demanganization, and reduce the reaction of MnO in the slag to the molten steel. Fluorite helps to further melt the sintered lime, which can effectively improve its utilization rate. Exemplarily, the amount of the above-mentioned sintered lime can be 1000kg, 1200kg, 1400kg, 1600kg, 1800kg, 2000kg, etc., and the amount of fluorite can be 100kg, 120kg, 140kg, 160kg, 180kg, 200kg, etc. In addition, during the steel tapping, the molten steel in the converter is poured into the ladle, and the bottom blowing intensity of the ladle is not less than 0.07Nm 3 / t / min. In addition, after the steel is tapped, the second slag pouring is carried out and all the slag is poured out.

[0071] In some embodiments, the process of blowing the steelmaking raw materials by top and bottom combined blowing of a converter to obtain blown steel liquid comprises:

[0072] The steelmaking raw materials are blown by the converter top and bottom combined blowing method, and the oxygen lance position is set according to the oxygen blowing ratio of the blowing; when the oxygen blowing ratio is 0, the corresponding oxygen lance position is 2.2m; when the oxygen blowing ratio is 50%, the corresponding oxygen lance position is 2.0m; when the oxygen blowing ratio is 70%, the corresponding oxygen lance position is 1.8m; when the oxygen blowing ratio is 80%, the corresponding oxygen lance position is 1.6m.

[0073] In the embodiment of the present application, the oxygen lance position is set according to the oxygen blowing ratio of the blowing, so that the FeO content in the slag can always be kept at a high level, which is beneficial to the whole process of manganese removal and can effectively reduce the manganese return during the blowing process.

[0074] The present application will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are intended only to illustrate the present application and are not intended to limit the scope of the present application. The experimental methods for which specific conditions are not specified in the following examples are usually measured according to national standards. If there is no corresponding national standard, then the conditions recommended by the manufacturer are followed.

[0075] Example 1

[0076] S11, using a converter top and bottom combined blowing method to blow the steelmaking raw materials to obtain blown steel liquid; wherein,

[0077] The top oxygen supply intensity is 3.18Nm 3 / t / min, the top oxygen supply flow is 44000Nm3 / h, the bottom air supply intensity is 0.06Nm 3 / t / min.

[0078] The steelmaking raw materials are blown by the converter top and bottom combined blowing method to obtain blown steel liquid;

[0079] The method of using a converter top and bottom combined blowing method to blow steel-making raw materials to obtain blown steel liquid comprises:

[0080] The steel-making raw materials are subjected to a first blowing process, during which a first slag-making material is added to the steel-making raw materials to form a slag with a first basicity, and then a first slag pouring process is performed to obtain a first blown steel liquid;

[0081] First, add 41t of scrap steel, then 7.3t of limestone, and finally 212t of molten iron;

[0082] When the oxygen blowing ratio is 6%, 6t of lime, 2.5t of light-burned dolomite and 4t of ore are added in order to form a slag with a first basicity of 2.1, and then a first slag pouring treatment is performed with a slag pouring amount of 8t to obtain a first blowing molten steel;

[0083] The first blown steel liquid is subjected to a second blown process, and a second slag-making material is added to the first blown steel liquid during the second blown process to obtain a blown steel liquid; wherein,

[0084] 4t of lime, 2t of limestone, and 1.5t of first ore are added when the oxygen blowing ratio is 25%. The amount of first ore is 5Kg / t of steel;

[0085] 2.2t of the second ore is added at an oxygen blowing ratio of 75%, the dosage of the second ore is 10kg / t, and the basicity of the slag generated by the second slag-making material is 3.3.

[0086] The first blowing time is 4 minutes, and the second blowing time is 14 minutes;

[0087] In the above S11, when the oxygen blowing ratio is 0, the corresponding oxygen lance position is 2.2m; when the oxygen blowing ratio is 50%, the corresponding oxygen lance position is 2.0m; when the oxygen blowing ratio is 70%, the corresponding oxygen lance position is 1.8m; when the oxygen blowing ratio is 80%, the corresponding oxygen lance position is 1.6m.

[0088] S21, controlling the temperature and oxygen activity of the blown molten steel to obtain molten steel to be tapped; the temperature of the molten steel to be tapped is 1612° C., and the oxygen activity is 665 ppm;

[0089] S31, tapping the molten steel to be tapped, and adding a third slag-making material to the tapped molten steel during the tapping process to obtain molten manganese steel; wherein the third slag-making material comprises: 1200 kg of sintered lime and 105 kg of fluorite.

[0090] Example 2

[0091] S11, using a converter top and bottom combined blowing method to blow the steelmaking raw materials to obtain blown steel liquid; wherein,

[0092] The top oxygen supply intensity is 3.18Nm 3 / t / min, the top oxygen supply flow is 44000Nm 3 / h, the bottom air supply intensity is 0.06Nm 3 / t / min.

[0093] The steelmaking raw materials are blown by the converter top and bottom combined blowing method to obtain blown steel liquid;

[0094] The method of using a converter top and bottom combined blowing method to blow steel-making raw materials to obtain blown steel liquid comprises:

[0095] The steel-making raw materials are subjected to a first blowing process, during which a first slag-making material is added to the steel-making raw materials to form a slag with a first basicity, and then a first slag pouring process is performed to obtain a first blown steel liquid;

[0096] First, add 43t of scrap steel, then add 6.5t of limestone, and finally add 210t of molten iron;

[0097] When the oxygen blowing ratio is 6%, 5.5t of lime, 2.8t of light-burned dolomite and 4.5t of ore are added in order to form a slag with a first basicity of 2.0, and then a first slag pouring treatment is performed with a slag pouring amount of 7.5t to obtain a first blowing molten steel;

[0098] The first blown steel liquid is subjected to a second blown process, and a second slag-making material is added to the first blown steel liquid during the second blown process to obtain a blown steel liquid; wherein,

[0099] 4.5t lime, 2t limestone, 1t first ore, added when the oxygen blowing ratio is 25%, the amount of first ore is 5Kg / t steel;

[0100] 2t of the second ore is added at an oxygen blowing ratio of 75%, the dosage of the second ore is 8.6kg / t, and the basicity of the slag generated by the second slag-making material is 3.5.

[0101] The first blowing time is 5 minutes, and the second blowing time is 13 minutes;

[0102] In the above S12, when the oxygen blowing ratio is 0, the corresponding oxygen lance position is 2.2m; when the oxygen blowing ratio is 50%, the corresponding oxygen lance position is 2.0m; when the oxygen blowing ratio is 70%, the corresponding oxygen lance position is 1.8m; when the oxygen blowing ratio is 80%, the corresponding oxygen lance position is 1.6m.

[0103] S22, controlling the temperature and oxygen activity of the blown molten steel to obtain molten steel to be tapped; the temperature of the molten steel to be tapped is 1605° C., and the oxygen activity is 608 ppm;

[0104] S32, tapping the molten steel to be tapped, and adding a third slag-making material to the tapped molten steel during the tapping process to obtain molten manganese steel; wherein the third slag-making material comprises: 1020 kg of sintered lime and 107 kg of fluorite.

[0105] Example 3

[0106] S13, using a converter top and bottom combined blowing method to blow the steelmaking raw materials to obtain blown steel liquid; wherein,

[0107] The top oxygen supply intensity is 3.26Nm 3 / t / min, the top oxygen supply flow is 45000Nm 3 / h, the bottom air supply intensity is 0.05Nm 3 / t / min.

[0108] The steelmaking raw materials are blown by the converter top and bottom combined blowing method to obtain blown steel liquid;

[0109] The method of using a converter top and bottom combined blowing method to blow steel-making raw materials to obtain blown steel liquid comprises:

[0110] The steel-making raw materials are subjected to a first blowing process, during which a first slag-making material is added to the steel-making raw materials to form a slag with a first basicity, and then a first slag pouring process is performed to obtain a first blown steel liquid;

[0111] First, add 39 tons of scrap steel, then add 5.5 tons of limestone; finally, add 215 tons of molten iron;

[0112] When the oxygen blowing ratio is 6%, 5t of lime, 3t of light-burned dolomite and 3.5t of ore are added in order to form a slag with a first basicity of 2.0, and then a first slag pouring treatment is performed with a slag pouring amount of 6.8t to obtain a first blowing molten steel;

[0113] The first blown steel liquid is subjected to a second blown process, and a second slag-making material is added to the first blown steel liquid during the second blown process to obtain a blown steel liquid; wherein,

[0114] 4t of lime, 1t of limestone, and 1.5t of first ore are added when the oxygen blowing ratio is 25%. The amount of first ore is 6.5Kg / t of steel;

[0115] 2t of the second ore is added at an oxygen blowing ratio of 75%, the dosage of the second ore is 8.6kg / t, and the basicity of the slag generated by the second slag-making material is 3.7.

[0116] The first blowing time is 4 minutes, and the second blowing time is 13 minutes;

[0117] In the above S13, when the oxygen blowing ratio is 0, the corresponding oxygen lance position is 2.2m; when the oxygen blowing ratio is 50%, the corresponding oxygen lance position is 2.0m; when the oxygen blowing ratio is 70%, the corresponding oxygen lance position is 1.8m; when the oxygen blowing ratio is 80%, the corresponding oxygen lance position is 1.6m.

[0118] S23, controlling the temperature and oxygen activity of the blown molten steel to obtain molten steel to be tapped; the temperature of the molten steel to be tapped is 1601° C., and the oxygen activity is 672 ppm;

[0119] S33, tapping the molten steel to be tapped, and adding a third slag-making material to the tapped molten steel during the tapping process to obtain molten manganese steel; wherein the third slag-making material comprises: 1089 kg of sintered lime and 110 kg of fluorite.

[0120] Comparative Example 1

[0121] S14, using a converter top and bottom combined blowing method to blow the steelmaking raw materials to obtain blown steel liquid; wherein,

[0122] The top oxygen supply intensity is 3.18Nm 3 / t / min, and or the top oxygen supply flow rate is 44000Nm 3 / h, the bottom air supply intensity is 0.03Nm 3 / t / min.

[0123] The steelmaking raw materials are blown by the converter top and bottom combined blowing method to obtain blown steel liquid;

[0124] The method of using a converter top and bottom combined blowing method to blow steel-making raw materials to obtain blown steel liquid comprises:

[0125] The steel-making raw materials are blown once to obtain blown steel liquid; the blowing time is 18 minutes;

[0126] First, 43 tons of scrap steel was added, and finally 210 tons of molten iron was added;

[0127] When the oxygen blowing ratio is 6%, add 5.5t lime, 2.8t light-burned dolomite and 4.5t ore in sequence;

[0128] When the oxygen blowing ratio is 25%, add 4.5t lime, 2t limestone, and 3t ore in order; the slag basicity is 3;

[0129] S24, controlling the temperature and oxygen activity of the blown molten steel to obtain molten steel to be tapped; the temperature of the molten steel to be tapped is 1605° C., and the oxygen activity is 698 ppm;

[0130] S34, tapping the molten steel to be tapped, and adding a third slag-making material to the tapped molten steel during the tapping process to obtain molten manganese steel; wherein the third slag-making material comprises: 1020 kg of sintered lime and 107 kg of fluorite.

[0131] Comparative Example 2

[0132] S15, using a converter top and bottom combined blowing method to blow the steelmaking raw materials to obtain blown steel liquid; wherein,

[0133] The top oxygen supply intensity is 3.10Nm 3 / t / min, and or the top oxygen supply flow rate is 42000Nm 3 / h, the bottom air supply intensity is 0.03Nm 3 / t / min.

[0134] The steelmaking raw materials are blown by the converter top and bottom combined blowing method to obtain blown steel liquid;

[0135] The method of using a converter top and bottom combined blowing method to blow steel-making raw materials to obtain blown steel liquid comprises:

[0136] The steel-making raw materials are blown once to obtain blown steel liquid; the blowing time is 18 minutes;

[0137] First, add 40t of scrap steel, and finally add 210t of molten iron;

[0138] When the oxygen blowing ratio is 6%, add 7.5t lime, 3t light-burned dolomite and 5.5t ore in sequence;

[0139] When the oxygen blowing ratio is 25%, add 2.5t lime, 2t limestone, 3t ore in order, and the slag basicity is 2.9;

[0140] S25, controlling the temperature and oxygen activity of the blown molten steel to obtain molten steel to be tapped; the temperature of the molten steel to be tapped is 1620° C., and the oxygen activity is 555 pm;

[0141] S35, tapping the molten steel to be tapped, and adding a third slag-making material to the tapped molten steel during the tapping process to obtain molten manganese steel; wherein the third slag-making material comprises: 1002 kg of sintered lime and 99 kg of fluorite.

[0142] The manganese content in the molten manganese steel obtained in Examples 1 to 3 and Comparative Examples 1 to 2 was tested, and the test results are shown in Table 2.

[0143] Table 2 Manganese content in manganese steel liquid

[0144] Serial number Manganese / wt% Example 1 0.020 Example 2 0.018 Example 3 0.017 Comparative Example 1 0.045 Comparative Example 2 0.052

[0145] It can be seen from Table 2 that, through the manganese steel smelting method provided in the embodiment of the present application, the manganese in the molten steel can be effectively removed by the manganese steel smelting process using two blowing processes, and the manganese content of the molten steel can be stabilized below 0.02%, which achieves better results for smelting low-manganese steel grades; while the comparative examples 1 to 2 cannot obtain the manganese steel liquid with a lower manganese content as shown in Examples 1 to 3 by using one blowing process.

[0146] One or more technical solutions in the embodiments of the present application also have at least the following technical effects or advantages:

[0147] (1) The large-flow gas agitation by top and bottom combined blowing makes the slag interface reaction more complete and effective, achieving a very ideal demanganese metallurgical effect;

[0148] (2) lime, light-burned dolomite, limestone and ore are used as the first slag-making material and the second slag-making material, and the order, amount and timing of adding materials are specified. Different adding orders can meet better demanganese conditions;

[0149] (3) Setting the oxygen lance position control mode can effectively reduce manganese return during the blowing process;

[0150] (4) Using the third slag-making raw material to sinter lime and fluorite, and using large flow rate stirring at the same time, a lower manganese content can be obtained;

[0151] (5) The first slag-making material used in the first blowing can form slag quickly, and the ability of slag to absorb manganese in molten iron is enhanced, which is more conducive to manganese removal;

[0152] (6) Reasonable gun position control is more conducive to the formation of iron oxide in the slag and accelerates the slag-metal interface reaction during manganese removal;

[0153] (7) The top and bottom combined blowing converter method is used to fully utilize the thermodynamic and kinetic conditions for hot metal dephosphorization;

[0154] (8) Lightly burned dolomite is used as the slagging agent, which can protect the furnace lining and increase the service life of the converter while ensuring fast slagging.

[0155] (9) It is easier to obtain relatively low manganese by using low temperature steelmaking conditions.

[0156] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A method for smelting manganese steel, characterized in that: The method comprises: The steelmaking raw materials are blown by the converter top and bottom combined blowing method to obtain blown steel liquid; The method of using a converter top and bottom combined blowing method to blow steel-making raw materials to obtain blown steel liquid comprises: The steel-making raw materials are subjected to a first blowing process, during which a first slag-making material is added to the steel-making raw materials to form a slag with a first basicity, and then a first slag pouring process is performed to obtain a first blown steel liquid; subjecting the first blown steel liquid to a second blown process, and adding a second slag-making material to the first blown steel liquid during the second blown process to obtain a blown steel liquid; Controlling the temperature and oxygen activity of the blowing molten steel to obtain molten steel to be tapped; The molten steel to be tapped is tapped, and during the tapping process, a third slag-making material is added to the tapped molten steel to obtain molten manganese steel.

2. The method according to claim 1, characterized in that The temperature of the molten steel to be tapped is 1590° C. to 1610° C., and the oxygen activity of the molten steel to be tapped is 500ppm to 700ppm.

3. The method according to claim 1, characterized in that The first basicity is 1.5-2.

5.

4. The method according to claim 1 or 3, characterized in that: The step of adding a first slag-making material to the steel-making raw material in the first blowing process to form a slag with a first basicity comprises: In the first blowing process, a first slag-making material is added to the steel-making raw materials to form a slag with a first basicity; wherein the first slag-making material comprises: lime, limestone, light-burned dolomite and ore; The steelmaking raw materials include molten iron, and the limestone is added before adding the molten iron, with the total amount not less than 30kg / t steel; When the oxygen blowing ratio reaches 6%, the lime, the light-burned dolomite and the ore are added in sequence, and the amount of the ore is 10Kg / t steel to 15Kg / t steel.

5. The method according to claim 1, characterized in that The basicity of the second slag formed by the second slag-making material is 3-4.

6. The method according to claim 1 or 5, characterized in that: The adding of a second slag-making material to the first blown steel liquid during the second blowing process comprises: In the second blowing process, a second slag-making material is added to the first blowing molten steel; wherein the second slag-making material comprises lime, limestone, light-burned dolomite, a first ore and a second ore; The lime, the limestone and the first ore are added when the oxygen blowing ratio is 25%, and the amount of the first ore is 5 kg / t steel; The second ore is added when the oxygen blowing ratio is 56-75%, and the amount of the second ore is not less than 5Kg / t steel.

7. The method according to claim 1, characterized in that The first blowing time is 4 minutes to 5 minutes, and / or the second blowing time is 13 minutes to 14 minutes.

8. The method according to claim 1, characterized in that The process parameters of the converter top-bottom combined blowing method include: converter top oxygen supply intensity, converter top oxygen supply flow rate and converter bottom gas supply intensity; wherein, The oxygen supply intensity at the top of the converter is 3.04Nm 3 / t / min~3.18Nm 3 / t / min, the oxygen flow rate at the top of the converter is 42000Nm 3 / h~45000Nm 3 / h, the gas supply intensity at the bottom of the converter is 0.05Nm 3 / t / min~0.07Nm 3 / t / min.

9. The method according to claim 1, characterized in that: The third slag-making material includes sintered lime and fluorite; wherein, The amount of the sintered lime is 1000kg to 2000kg, and the amount of the fluorite is 100kg to 200kg.

10. The method according to claim 1, characterized in that The method of using a converter top and bottom combined blowing method to blow steel-making raw materials to obtain blown steel liquid comprises: The steelmaking raw materials are blown by the converter top and bottom combined blowing method, and the oxygen lance position is set according to the oxygen blowing ratio of the blowing; when the oxygen blowing ratio is 0, the corresponding oxygen lance position is 2.2m; when the oxygen blowing ratio is 50%, the corresponding oxygen lance position is 2.0m; when the oxygen blowing ratio is 70%, the corresponding oxygen lance position is 1.8m; when the oxygen blowing ratio is 80%, the corresponding oxygen lance position is 1.6m.

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