Method for preparing dephosphorizing agent from iron-containing solid waste, dephosphorizing agent and converter steelmaking method

Abstract

The invention provides a method for preparing a dephosphorizing agent from iron-containing solid waste, the dephosphorizing agent and a converter steelmaking method, and belongs to the technical field of smelting. The method comprises the following steps: mixing iron-containing solid waste, lime, limestone and coke according to a set mass ratio to obtain a mixture; mixing the mixture with a solvent, and granulating to obtain granules; and sintering the granules to obtain the dephosphorizing agent. The raw material composition of the dephosphorizing agent is reasonably designed, the iron-containing solid waste and the lime can generate calcium ferrite with good slagging and dephosphorizing capacity in the sintering process, the alkalinity of the dephosphorizing agent can be improved through the mass ratio, dephosphorizing reaction in a converter is facilitated, and meanwhile the high-temperature strength and other performance of the dephosphorizing agent can be improved through the existence of the limestone. The obtained dephosphorizing agent can be used for the dephosphorizing process of converter smelting, the feeding amount of the iron-containing solid waste of the steel plant in the converter is increased, and efficient cyclic utilization of solid waste resources in the steel plant is achieved.

Description

Technical Field

[0001] The present application relates to the field of smelting technology, and in particular to a method for preparing a dephosphorization agent using iron-containing solid waste, a dephosphorization agent and a converter steelmaking method. Background Art

[0002] Based on a number of policy documents such as the "Implementation Plan for Accelerating the Comprehensive Utilization of Industrial Resources", the country requires vigorously promoting the reduction of industrial solid waste and large-scale efficient comprehensive utilization in key industries. The solid waste generated by steel enterprises mainly includes steelmaking slag, dust removal ash, etc.

[0003] In the converter production process, iron-containing solid waste is usually used as a coolant and added into the furnace along with the slag-making material. The appropriate amount of solid waste not only helps to reduce production costs, but also helps to balance the heat in the furnace. However, when the amount of solid waste is large, due to the large amount of iron oxides in it, the chemical reaction in the furnace is bound to be affected, which will cause negative effects such as reduced blowing stability, reduced dephosphorization rate, increased lime consumption, and increased metal material consumption. Therefore, it is urgent to develop a method that can effectively increase the amount of iron-containing solid waste in steel plants. Summary of the invention

[0004] The present application provides a method for preparing a dephosphorization agent using iron-containing solid waste, a dephosphorization agent and a converter steelmaking method to solve the following technical problem: how to increase the consumption of iron-containing solid waste in a steel plant in a furnace.

[0005] In a first aspect, the present application provides a method for preparing a dephosphorization agent using iron-containing solid waste, the method comprising:

[0006] The iron-containing solid waste, lime, limestone and coke are mixed according to a set mass ratio to obtain a mixture; the set mass ratio is iron-containing solid waste: lime: limestone: coke = (80-85): (4-12): (3-9): (1-5);

[0007] The mixed material is mixed with a solvent, and then granulated to obtain a granular material;

[0008] The granular material is sintered to obtain a dephosphorization agent.

[0009] Optionally, the set mass ratio is iron-containing solid waste: lime: limestone: coke = (80-85): (7-9): (5-7): (2-4).

[0010] Optionally, the particle sizes of the iron-containing solid waste, limestone and coke are all 1 mm to 3 mm, and the particle size of the lime is less than 1 mm.

[0011] Optionally, the sintering includes the following parameters: a sintering temperature of 1200°C to 1300°C, a sintering time of 40min to 50min, and a sintering end point temperature of 300°C to 400°C.

[0012] In a second aspect, the present application provides a dephosphorization agent prepared by the method described in any one of the embodiments of the first aspect, wherein the dephosphorization agent is a granular dephosphorization agent, and the diameter of the granular dephosphorization agent is 30 mm to 50 mm.

[0013] In a third aspect, the present application provides a converter steelmaking method, the method comprising:

[0014] Obtaining the dephosphorization agent described in the embodiment of the second aspect;

[0015] The dephosphorizing agent and limestone are added in stages according to corresponding addition amounts; wherein,

[0016] Mixing the dephosphorizing agent in the first-stage addition amount, the limestone in the first-stage addition amount, molten iron and scrap steel to obtain steelmaking raw materials;

[0017] The steel-making raw materials are blown in a converter, and the remaining dephosphorization agent and limestone are added in corresponding amounts in the remaining stages to obtain converter molten steel.

[0018] Optionally, the first-stage addition amount of the dephosphorizing agent is 14 kg / t·steel to 17.5 kg / t·steel, and the first-stage addition amount of the limestone is 5 kg / t·steel to 5.5 kg / t·steel.

[0019] Optionally, the steelmaking raw materials are subjected to converter blowing, and the remaining dephosphorization agent and limestone are added in the remaining stages according to corresponding addition amounts, including:

[0020] The steelmaking raw materials are blown in a converter, and the remaining dephosphorization agent and limestone are added in corresponding amounts in the remaining stages according to the oxygen blowing amount; wherein,

[0021] When the oxygen blowing amount is 2% to 5%, the limestone having the second stage addition amount is added; the second stage addition amount of the limestone is 3kg / t·steel to 3.5kg / t·steel;

[0022] When the oxygen blowing amount is 25% to 30%, the limestone having the third stage addition amount is added; the third stage addition amount of the limestone is 1.5 kg / t·steel to 2 kg / t·steel;

[0023] When the oxygen blowing amount is 55% to 65%, the dephosphorization agent having the second stage addition amount is added in batches; the second stage addition amount of the dephosphorization agent is 6kg / t·steel to 7.5kg / t·steel, and the addition amount of the dephosphorization agent per batch is 450kg to 550kg.

[0024] Optionally, in the process of adding the remaining dephosphorization agent and limestone in the remaining stage according to the corresponding addition amounts, the method further comprises:

[0025] According to the oxygen blowing amount, lime and light-burned dolomite are added in stages according to the corresponding addition amount;

[0026] When the oxygen blowing amount is 2% to 5%, the lime and light-burned dolomite with the first-stage addition amount are added; the first-stage addition amount of the lime is 8.5kg / t·steel to 10kg / t·steel, and the first-stage addition amount of the light-burned dolomite is 5kg / t·steel to 5.5kg / t·steel;

[0027] When the oxygen blowing amount is 25% to 30%, the lime and light-burned dolomite having the second-stage addition amount are added; the second-stage addition amount of the lime is 8.5kg / t·steel to 10kg / t·steel, and the second-stage addition amount of the light-burned dolomite is 14.5kg / t·steel to 17kg / t·steel.

[0028] Optionally, measured by mass fraction, the P content of the converter final molten steel is ≤0.010%, and the O content is ≤0.055%; the temperature of the converter final molten steel is 1620°C~1640°C; the final slag basicity of the converter blowing is 3.0~3.5, and the FeO content of the final slag is 16%~20%, and the MgO content of the final slag is 9%~15%.

[0029] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0030] The present application provides a method for preparing a dephosphorization agent using iron-containing solid waste, including: mixing iron-containing solid waste, lime, limestone and coke according to a set mass ratio to obtain a mixture; the set mass ratio is iron-containing solid waste: lime: limestone: coke = (80-85): (4-12): (3-9): (1-5); mixing the mixture with a solvent, and then granulating to obtain a granular material; sintering the granular material to obtain a dephosphorization agent. The raw material composition of the dephosphorization agent is reasonably designed, and the iron-containing solid waste and lime can generate calcium ferrite with good slagging and dephosphorization capabilities during the sintering process, and this mass ratio can increase the alkalinity of the dephosphorization agent, which is conducive to the dephosphorization reaction in the converter. At the same time, the presence of limestone helps to improve the high-temperature strength and other properties of the dephosphorization agent. The dephosphorization agent thus obtained can be used in the dephosphorization process of converter smelting, which increases the amount of iron-containing solid waste in the furnace of the steel plant and realizes the efficient recycling of solid waste resources in the steel plant. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] 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.

[0032] In order to more clearly illustrate the embodiments of the present application or the technical solutions in 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.

[0033] Figure 1 A schematic flow chart of a method for preparing a dephosphorization agent using iron-containing solid waste provided in an embodiment of the present application;

[0034] Figure 2 A schematic flow chart of a converter steelmaking method 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 addition, in the description of the specification of the present application, the terms "including", "comprising", etc. mean "including but not limited to". In this article, relational terms such as "first" and "second", etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such 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 represent: A exists alone, A and B exist at the same time, and B exists alone. Wherein A and B can be singular or plural. In this article, "at least one" means one or more, and "plurality" means two or more. "At least one", "the following at least one item (items)" or similar expressions refer to any combination of these items, including any combination of single items (items) or plural items (items). For example, "at least one of a, b, or c", or "at least one of a, b and c", can both mean: a, b, c, ab (i.e. a and b), ac, bc or abc, where a, b, c can be single or plural, respectively.

[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] Figure 1 A schematic flow chart of a method for preparing a dephosphorization agent using iron-containing solid waste provided in an embodiment of the present application;

[0040] See also Figure 1 The present application provides a method for preparing a dephosphorization agent using iron-containing solid waste, the method comprising:

[0041] S11, mixing iron-containing solid waste, lime, limestone and coke according to a set mass ratio to obtain a mixture; the set mass ratio is iron-containing solid waste: lime: limestone: coke = (80-85): (4-12): (3-9): (1-5);

[0042] The positive effect of controlling iron-containing solid waste: lime: limestone: coke = (80-85): (4-12): (3-9): (1-5): iron-containing solid waste and lime can generate calcium ferrite with good slagging and dephosphorization ability during the sintering process, and this mass ratio can increase the alkalinity of the dephosphorization agent, which is helpful for the dephosphorization reaction in the converter. The presence of limestone helps to improve the high-temperature strength and other properties of the dephosphorization agent. Exemplarily, the mass ratio of iron-containing solid waste: lime: limestone: coke can be 80:8:6:3, 81:8:6:3, 82:8:6:3, 84:8:6:3, 85:8:6:3, 82:4:6:2, 82:6:6:2, 82:8:6:2, 82:10:6:2, 82:12:6:2, 82:6:3:2, 82:6:5:2, 82:6:7:2, 82:6:9:2, etc.

[0043] In some embodiments, the particle sizes of the iron-containing solid waste, limestone and coke are all 1 mm to 3 mm, and the particle size of the lime is less than 1 mm.

[0044] In some embodiments, the set mass ratio is iron-containing solid waste: lime: limestone: coke = (80-85): (7-9): (5-7): (2-4).

[0045] S21, mixing the mixed material with a solvent, and then granulating to obtain a granular material;

[0046] In some embodiments, the solvent is water and the like.

[0047] S31, sintering the granular material to obtain a dephosphorization agent.

[0048] In some embodiments, the sintering includes the following parameters: a sintering temperature of 1200°C to 1300°C, a sintering time of 40 min to 50 min, and a sintering end point temperature of 300°C to 400°C.

[0049] It should be noted that the specific process of sintering includes: feeding the granular material into the sintering device, heating it to 1200℃~1300℃, and maintaining this temperature for 40min~50min, then cooling it to 300℃~400℃ in the sintering device, taking the dephosphorization agent out of the sintering device, and cooling it to room temperature to obtain the dephosphorization agent.

[0050] By controlling the process parameters of sintering, it is helpful to form calcium ferrite in the dephosphorizing agent and to improve the high temperature strength and density of the sintered ore. For example, the sintering temperature can be 1200°C, 1220°C, 1240°C, 1260°C, 1280°C, 1300°C, etc., the sintering time can be 40min, 42min, 44min, 46min, 48min, 50min, etc., and the sintering end temperature can be 300°C, 320°C, 340°C, 360°C, 380°C, 400°C, etc.

[0051] The present application provides a dephosphorization agent, which is a granular dephosphorization agent with a diameter of 30 mm to 50 mm.

[0052] The reasons for using granular dephosphorization agents in the converter blowing process are: ① Such dephosphorization agents have a low melting point, which is beneficial to the early slagging of the converter; ② Such dephosphorization agents have high basicity, which helps to slow down the erosion of the furnace lining and facilitates the maintenance of the furnace; ③ The use of such dephosphorization agents helps to improve the metal recovery rate; ④ Pressing the dephosphorization agent into granules is not only convenient for transportation, but also conducive to the loading of the converter feeding system. Exemplarily, the diameter of the granular dephosphorization agent can be 30mm, 32mm, 35mm, 40mm, 45mm, 50mm, etc.

[0053] The dephosphorization agent is realized based on the preparation method of the above-mentioned dephosphorization agent. The specific steps of the preparation method of the dephosphorization agent can refer to the above-mentioned embodiment. Since the dephosphorization agent adopts part or all of the technical solutions of the above-mentioned embodiment, it has at least all the beneficial effects brought by the technical solutions of the above-mentioned embodiment, which will not be repeated here one by one.

[0054] Figure 2 A schematic flow chart of a converter steelmaking method provided in an embodiment of the present application.

[0055] See also Figure 2 , the present application provides a converter steelmaking method, the method comprising:

[0056] S12, obtaining a dephosphorizing agent;

[0057] S22, adding the dephosphorizing agent and limestone in stages according to corresponding addition amounts; wherein,

[0058] S32, mixing the dephosphorizing agent having the first stage addition amount, the limestone having the first stage addition amount, molten iron and scrap steel to obtain steelmaking raw materials;

[0059] In some embodiments, molten iron accounts for 85% to 90% of the total charge, with the remainder being scrap steel.

[0060] The reasons for adopting this charge amount are: ① In the production process, the cost of scrap steel is greater than that of molten iron; ② Using some scrap steel can consume the heat in the furnace, which is helpful for controlling the stability of converter blowing. For example, molten iron accounts for 85%, 86%, 87%, 88%, 89%, 90% of the total charge amount, etc.

[0061] In some embodiments, the first-stage addition amount of the dephosphorizing agent is 14 kg / t·steel to 17.5 kg / t·steel, and the first-stage addition amount of the limestone is 5 kg / t·steel to 5.5 kg / t·steel.

[0062] S42, subjecting the steelmaking raw materials to converter blowing, and adding the remaining dephosphorization agent and limestone in the remaining stages according to corresponding addition amounts to obtain converter molten steel.

[0063] In some embodiments, the steelmaking raw materials are subjected to converter blowing, and the remaining dephosphorization agent and limestone are added in the remaining stages according to corresponding addition amounts, including:

[0064] The steelmaking raw materials are blown in a converter, and the remaining dephosphorization agent and limestone are added in corresponding amounts in the remaining stages according to the oxygen blowing amount; wherein,

[0065] When the oxygen blowing amount is 2% to 5%, the limestone having the second stage addition amount is added; the second stage addition amount of the limestone is 3kg / t·steel to 3.5kg / t·steel;

[0066] When the oxygen blowing amount is 25% to 30%, the limestone having the third stage addition amount is added; the third stage addition amount of the limestone is 1.5 kg / t·steel to 2 kg / t·steel;

[0067] When the oxygen blowing amount is 55% to 65%, the dephosphorization agent having the second stage addition amount is added in batches; the second stage addition amount of the dephosphorization agent is 6kg / t·steel to 7.5kg / t·steel, and the addition amount of the dephosphorization agent per batch is 450kg to 550kg.

[0068] It should be noted that the oxygen blowing amount in the present application refers to the volume fraction of the top blowing oxygen supply to the total oxygen supply.

[0069] During the converter blowing process, adding dephosphorization agent and limestone to the furnace in stages has a positive effect: the thermal state in the converter is different at different blowing stages. Adding dephosphorization agent and limestone in stages not only helps the formation of slag, but also helps to improve the dephosphorization rate and improve the blowing stability.

[0070] In some embodiments, during the process of adding the remaining dephosphorization agent and limestone in the remaining stage according to the corresponding addition amounts, the method further comprises:

[0071] According to the oxygen blowing amount, lime and light-burned dolomite are added in stages according to the corresponding addition amount;

[0072] When the oxygen blowing amount is 2% to 5%, the lime and light-burned dolomite with the first-stage addition amount are added; the first-stage addition amount of the lime is 8.5kg / t·steel to 10kg / t·steel, and the first-stage addition amount of the light-burned dolomite is 5kg / t·steel to 5.5kg / t·steel;

[0073] When the oxygen blowing amount is 25% to 30%, the lime and light-burned dolomite having the second-stage addition amount are added; the second-stage addition amount of the lime is 8.5kg / t·steel to 10kg / t·steel, and the second-stage addition amount of the light-burned dolomite is 14.5kg / t·steel to 17kg / t·steel.

[0074] The reason for adding lime and light-burned dolomite to the converter in stages during the converter blowing process is that the thermal state in the converter is different at different blowing stages. Adding lime and light-burned dolomite in stages not only helps the formation of slag, but also helps control the thermal state in the furnace and improve the blowing stability.

[0075] In some embodiments, during the converter blowing process, the top blowing oxygen supply intensity is 2.8 Nm 3 / t·min~3.1Nm 3 / t·min, oxygen lance height is 1.8m~2.2m, bottom blowing nitrogen intensity is 0.03Nm 3 / t·min~0.05Nm 3 / t·min.

[0076] In some embodiments, when the oxygen blowing amount is [0-40]%, the bottom blowing nitrogen intensity is 0.04Nm 3 / t·min; when the oxygen blowing amount is (40~75]%, the bottom blowing nitrogen intensity is 0.03Nm 3 / t·min; when the oxygen blowing amount is (75~100]%, the bottom blowing nitrogen intensity is 0.05Nm 3 / t·min.

[0077] In some embodiments, when the oxygen blowing amount is [0-6]%, the oxygen lance height is 2.2m; when the oxygen blowing amount is (6-16]%, the oxygen lance height is 2.0m; when the oxygen blowing amount is (16-100]%, the oxygen lance height is 1.8m.

[0078] In some embodiments, when the oxygen blowing amount is [0-45]%, the top blowing oxygen blowing intensity is slowly increased to 2.8 Nm 3 / t·min; when the oxygen blowing amount is (45~55]%, the top blowing oxygen blowing intensity is 3.0Nm 3 / t·min; when the oxygen blowing amount is (55~100]%, the top blowing oxygen blowing intensity is 3.1Nm 3 / t·min.

[0079] In some embodiments, the P content of the converter steel liquid is ≤0.010%, and the O content is ≤0.055%, measured by mass fraction; the temperature of the converter steel liquid is 1620°C to 1640°C; the basicity of the final slag of the converter blowing is 3.0 to 3.5, and the FeO content of the final slag is 16% to 20%, and the MgO content of the final slag is 9% to 15%, measured by mass fraction.

[0080] The reason for controlling the temperature of the molten steel after tapping to be between 1620°C and 1640°C is that a low tapping temperature is helpful for controlling the phosphorus mass fraction of the molten steel at the end point. For example, the temperature of the molten steel in the converter can be 1620°C, 1625°C, 1630°C, 1635°C, 1640°C, etc.

[0081] The reason for controlling the oxygen mass fraction of the molten steel after tapping to ≤ 0.055% is that it can not only ensure the reaction in the furnace, but also help reduce the consumption of metal materials. For example, the O content can be 0.040%, 0.042%, 0.045%, 0.050%, 0.052%, 0.055%, etc.

[0082] The basicity of the final slag is controlled to be 3.0-3.5. The reason for adopting this slag basicity control is that high basicity slag helps to improve the distribution ratio of phosphorus, thereby slowing down the phosphorus return in the later stage of converter smelting, and helps to slow down the erosion of the furnace lining. For example, the basicity of the final slag of the converter blowing can be 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, etc.

[0083] The reason for controlling the FeO content of the final slag to be between 16% and 20% is that it can ensure the reaction in the furnace and help reduce the consumption of metal materials. For example, the FeO content of the final slag can be 16%, 17%, 18%, 19%, 20%, etc.

[0084] The reason for controlling the final slag MgO to 9% to 15% is that it helps to adjust the slag viscosity and facilitates the implementation of the subsequent slag splashing furnace protection process. For example, the final slag MgO content can be 9%, 10%, 11%, 12%, 13%, 14%, 15%, etc.

[0085] The present application not only realizes the efficient allocation of solid waste resources in steel plants, which is beneficial to improving metal recovery and thus reducing production costs, but also, through the implementation of the corresponding steelmaking method, helps to reduce not only the total amount of slag, but also helps to reduce the occurrence of slag overflow or splashing during the blowing process, solving the problems of frequent slag overflow or explosive splashing and low dephosphorization rate in the current production process of large-scale allocation of solid waste in converters, thereby realizing efficient, green and low-cost production of converters.

[0086] 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 industry standards. If there is no corresponding industry standard, then the conditions recommended by the manufacturer are followed.

[0087] Example 1

[0088] This embodiment provides a method for preparing a dephosphorization agent using iron-containing solid waste, including the following method:

[0089] S111, mixing iron-containing solid waste, lime, limestone and coke according to a set mass ratio to obtain a mixture; the set mass ratio is iron-containing solid waste: lime: limestone: coke = 82.8:7.9:6.0:3.3;

[0090] S211, mixing the mixed material with water, and then granulating to obtain granular material;

[0091] S311, sintering the granular material, the sintering parameters include: sintering temperature of 1245°C, sintering time of 43min, sintering end temperature of 330°C, and then sieving to obtain a granular dephosphorization agent with a diameter of 30mm.

[0092] Based on the above dephosphorization agent, this embodiment also provides a converter steelmaking method, which uses a 210-ton top and bottom double-blown converter for smelting, including the following steps:

[0093] S121, obtaining a dephosphorizing agent;

[0094] S221, adding the dephosphorizing agent and limestone in stages according to corresponding addition amounts; wherein,

[0095] S321, mixing the dephosphorizing agent with the first-stage addition amount, the limestone with the first-stage addition amount, molten iron and scrap steel, wherein the molten iron charged into the furnace accounts for 86% of the total charge amount, to obtain steelmaking raw materials; the first-stage addition amount of the dephosphorizing agent is 3.1 t, and the first-stage addition amount of the limestone is 1.0 t;

[0096] S421, the steel-making raw materials are subjected to converter blowing, and according to the oxygen blowing amount, the remaining dephosphorization agent and limestone are added in the remaining stage according to the corresponding addition amount; wherein, when the oxygen blowing amount is 3%, the limestone with the second stage addition amount is added; the second stage addition amount of the limestone is 0.65t; at the same time, the lime and light-burned dolomite with the first stage addition amount are added; the first stage addition amount of the lime is 1.8t, and the first stage addition amount of the light-burned dolomite is 1.1t; when the oxygen blowing amount is When the oxygen blowing amount is 27%, the limestone with the third stage addition amount is added; the third stage addition amount of the limestone is 0.35t; the lime and light-burned dolomite with the second stage addition amount are added; the second stage addition amount of the lime is 1.8t, and the second stage addition amount of the light-burned dolomite is 3.2t; when the oxygen blowing amount is 60%, the dephosphorization agent with the second stage addition amount is added in batches; the second stage addition amount of the dephosphorization agent is 1.5t, and the addition amount of the dephosphorization agent per batch is 500kg.

[0097] The obtained converter molten steel was sampled before tapping, the molten steel temperature was 1640°C, the final P content was 0.056%, and the final O content was 0.0436%; the final slag sample was taken and analyzed, the final slag basicity was 3.2, FeO was 19.5%, and MgO was 13.3%.

[0098] Example 2

[0099] This embodiment provides a method for preparing a dephosphorization agent using iron-containing solid waste, including the following method:

[0100] S111, mixing iron-containing solid waste, lime, limestone and coke according to a set mass ratio to obtain a mixture; the set mass ratio is iron-containing solid waste: lime: limestone: coke = 81.8:8.7:6.6:3.6;

[0101] S211, mixing the mixed material with water, and then granulating to obtain granular material;

[0102] S311, sintering the granular material, the sintering parameters include: sintering temperature of 1250°C, sintering time of 42min, sintering end temperature of 370°C, and then sieving to obtain a granular dephosphorization agent with a diameter of 38mm.

[0103] Based on the above dephosphorization agent, this embodiment also provides a converter steelmaking method, which uses a 210-ton top and bottom double-blown converter for smelting, including the following steps:

[0104] S121, obtaining a dephosphorizing agent;

[0105] S221, adding the dephosphorizing agent and limestone in stages according to corresponding addition amounts; wherein,

[0106] S321, mixing the dephosphorizing agent with the first-stage addition amount, the limestone with the first-stage addition amount, molten iron and scrap steel, wherein the molten iron charged into the furnace accounts for 87% of the total charge amount, to obtain steelmaking raw materials; the first-stage addition amount of the dephosphorizing agent is 3.3 t, and the first-stage addition amount of the limestone is 1.1 t;

[0107] S421, the steel-making raw materials are subjected to converter blowing, and according to the oxygen blowing amount, the remaining dephosphorization agent and limestone are added in the remaining stage according to the corresponding addition amount; wherein, when the oxygen blowing amount is 2%, the limestone with the second stage addition amount is added; the second stage addition amount of the limestone is 0.7t; at the same time, the lime and light-burned dolomite with the first stage addition amount are added; the first stage addition amount of the lime is 2.0t, and the first stage addition amount of the light-burned dolomite is 1.1t; when the oxygen blowing amount is When the oxygen blowing amount is 27%, the limestone with the third stage addition amount is added; the third stage addition amount of the limestone is 0.4t; the lime and light-burned dolomite with the second stage addition amount are added; the second stage addition amount of the lime is 1.9t, and the second stage addition amount of the light-burned dolomite is 3.0t; when the oxygen blowing amount is 57%, the dephosphorization agent with the second stage addition amount is added in batches; the second stage addition amount of the dephosphorization agent is 1.5t, and the addition amount of the dephosphorization agent per batch is 500kg.

[0108] The obtained converter molten steel was sampled before tapping, the molten steel temperature was 1620°C, the final P content was 0.0076%, and the final O content was 0.0504%. The final slag sample was taken and analyzed, and the final slag basicity was 3.5, FeO was 19%, and MgO was 10.7%.

[0109] Example 3

[0110] This embodiment provides a method for preparing a dephosphorization agent using iron-containing solid waste, including the following method:

[0111] S111, mixing iron-containing solid waste, lime, limestone and coke according to a set mass ratio to obtain a mixture; the set mass ratio is iron-containing solid waste: lime: limestone: coke = 84.9:7.1:5.3:2.7;

[0112] S211, mixing the mixed material with water, and then granulating to obtain granular material;

[0113] S311, sintering the granular material, wherein the sintering parameters include: sintering temperature of 1250°C, sintering time of 40 minutes, sintering end temperature of 380°C, and then sieving to obtain a granular dephosphorization agent with a diameter of 45 mm.

[0114] Based on the above dephosphorization agent, this embodiment also provides a converter steelmaking method, which uses a 210-ton top and bottom double-blown converter for smelting, including the following steps:

[0115] S121, obtaining a dephosphorizing agent;

[0116] S221, adding the dephosphorizing agent and limestone in stages according to corresponding addition amounts; wherein,

[0117] S321, mixing the dephosphorizing agent with the first-stage addition amount, the limestone with the first-stage addition amount, molten iron and scrap steel, wherein the molten iron charged into the furnace accounts for 85% of the total charge amount, to obtain steelmaking raw materials; the first-stage addition amount of the dephosphorizing agent is 3.5 t, and the first-stage addition amount of the limestone is 1.0 t;

[0118] S421, the steel-making raw materials are subjected to converter blowing, and according to the oxygen blowing amount, the remaining dephosphorization agent and limestone are added in the remaining stage according to the corresponding addition amount; wherein, when the oxygen blowing amount is 3%, the limestone with the second stage addition amount is added; the second stage addition amount of the limestone is 0.7t; at the same time, the lime and light-burned dolomite with the first stage addition amount are added; the first stage addition amount of the lime is 2.0t, and the first stage addition amount of the light-burned dolomite is 1.0t; when the oxygen blowing amount is When the oxygen blowing amount is 26%, the limestone with the third stage addition amount is added; the third stage addition amount of the limestone is 0.4t; the lime and light-burned dolomite with the second stage addition amount are added; the second stage addition amount of the lime is 2.0t, and the second stage addition amount of the light-burned dolomite is 3.0t; when the oxygen blowing amount is 62%, the dephosphorization agent with the second stage addition amount is added in batches; the second stage addition amount of the dephosphorization agent is 1.0t, and the addition amount of the dephosphorization agent per batch is 500kg.

[0119] The obtained converter molten steel was sampled before tapping, the molten steel temperature was 1630°C, the final P content was 0.0085%, and the final O content was 0.0541%; the final slag sample was taken and analyzed, the final slag basicity was 3.3, FeO was 20%, and MgO was 14.6%.

[0120] Comparative Example 1

[0121] This comparative example provides a converter steelmaking method, which uses a 210-ton top and bottom combined blowing converter for smelting, comprising the following steps:

[0122] S121, mixing the limestone, molten iron and scrap steel in the first stage addition amount, charging 200t of molten iron into the furnace, accounting for 87% of the total charge amount, to obtain steelmaking raw materials; the first stage addition amount of limestone is 1.0t;

[0123] S221. The steelmaking raw materials are subjected to converter blowing, and the remaining limestone is added in corresponding amounts in the remaining stages according to the oxygen blowing amount; wherein, when the oxygen blowing amount is 3%, the limestone having the second-stage addition amount is added; the second-stage addition amount of the limestone is 0.7t; at the same time, the lime and light-burned dolomite having the first-stage addition amount are added; the first-stage addition amount of the lime is 2.0t, and the first-stage addition amount of the light-burned dolomite is 1.1t; when the oxygen blowing amount is 28%, the limestone having the third-stage addition amount is added; the third-stage addition amount of the limestone is 0.4t; the lime and light-burned dolomite having the second-stage addition amount are added; the second-stage addition amount of the lime is 2.0t, and the second-stage addition amount of the light-burned dolomite is 3.5t.

[0124] The obtained converter molten steel was sampled before tapping, the molten steel temperature was 1655°C, the final P content was 0.0105%, and the final O content was 0.0508%; the final slag sample was taken and analyzed, the final slag basicity was 3.2, FeO was 18%, and MgO was 11.2%.

[0125] In addition, one or more technical solutions in the embodiments of the present invention have at least the following technical effects or advantages:

[0126] In the embodiment of the present invention, by using iron-containing solid waste as raw material to prepare the dephosphorization agent, efficient recycling of solid waste resources in the steel plant is achieved, which is beneficial to improving the metal recovery rate and thus reducing production costs.

[0127] In the embodiments of the present invention, by improving the corresponding steelmaking method, it not only helps to reduce the total amount of slag, but also helps to reduce the occurrence of slag overflow or splashing during the blowing process, thereby solving the problems of frequent slag overflow or explosive splashing and low dephosphorization rate in the current production process of converters with large amounts of solid waste, thereby achieving efficient, green and low-cost production of converters.

[0128] 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 preparing a dephosphorization agent using iron-containing solid waste, characterized in that: The method comprises: The iron-containing solid waste, lime, limestone and coke are mixed according to a set mass ratio to obtain a mixture; the set mass ratio is iron-containing solid waste: lime: limestone: coke = (80-85): (4-12): (3-9): (1-5); The mixed material is mixed with a solvent, and then granulated to obtain a granular material; The granular material is sintered to obtain a dephosphorization agent.

2. The method according to claim 1, characterized in that The set mass ratio is iron-containing solid waste: lime: limestone: coke = (80-85): (7-9): (5-7): (2-4).

3. The method according to claim 1, characterized in that The particle sizes of the iron-containing solid waste, limestone and coke are all 1mm to 3mm, and the particle size of the lime is less than 1mm.

4. The method according to claim 1, characterized in that: The sintering process includes the following parameters: a sintering temperature of 1200°C to 1300°C, a sintering time of 40min to 50min, and a sintering end point temperature of 300°C to 400°C.

5. A dephosphorization agent prepared by the method according to any one of claims 1 to 4, characterized in that: The dephosphorization agent is a granular dephosphorization agent, and the diameter of the granular dephosphorization agent is 30 mm to 50 mm.

6. A converter steelmaking method, characterized in that: The method comprises: Obtaining the dephosphorization agent according to claim 5; The dephosphorizing agent and limestone are added in stages according to corresponding addition amounts; wherein, Mixing the dephosphorizing agent in the first-stage addition amount, the limestone in the first-stage addition amount, molten iron and scrap steel to obtain steelmaking raw materials; The steel-making raw materials are blown in a converter, and the remaining dephosphorization agent and limestone are added in corresponding amounts in the remaining stages to obtain converter molten steel.

7. The method according to claim 6, characterized in that The first-stage addition amount of the dephosphorizing agent is 14kg / t·steel to 17.5kg / t·steel, and the first-stage addition amount of the limestone is 5kg / t·steel to 5.5kg / t·steel.

8. The method according to claim 6, characterized in that The steelmaking raw materials are blown in a converter, and the remaining dephosphorization agent and limestone are added in the remaining stages according to corresponding addition amounts, including: The steelmaking raw materials are blown in a converter, and the remaining dephosphorization agent and limestone are added in corresponding amounts in the remaining stages according to the oxygen blowing amount; wherein, When the oxygen blowing amount is 2% to 5%, the limestone having the second stage addition amount is added; the second stage addition amount of the limestone is 3kg / t·steel to 3.5kg / t·steel; When the oxygen blowing amount is 25% to 30%, the limestone having the third stage addition amount is added; the third stage addition amount of the limestone is 1.5 kg / t·steel to 2 kg / t·steel; When the oxygen blowing amount is 55% to 65%, the dephosphorization agent having the second stage addition amount is added in batches; the second stage addition amount of the dephosphorization agent is 6kg / t·steel to 7.5kg / t·steel, and the addition amount of the dephosphorization agent per batch is 450kg to 550kg.

9. The method according to claim 8, characterized in that In the process of adding the remaining dephosphorization agent and limestone in the remaining stage according to the corresponding addition amounts, the method further comprises: According to the oxygen blowing amount, lime and light-burned dolomite are added in stages according to the corresponding addition amount; When the oxygen blowing amount is 2% to 5%, the lime and light-burned dolomite with the first-stage addition amount are added; the first-stage addition amount of the lime is 8.5kg / t·steel to 10kg / t·steel, and the first-stage addition amount of the light-burned dolomite is 5kg / t·steel to 5.5kg / t·steel; When the oxygen blowing amount is 25% to 30%, the lime and light-burned dolomite having the second-stage addition amount are added; the second-stage addition amount of the lime is 8.5kg / t·steel to 10kg / t·steel, and the second-stage addition amount of the light-burned dolomite is 14.5kg / t·steel to 17kg / t·steel.

10. The method according to claim 5, characterized in that Calculated by mass fraction, the P content of the converter final molten steel is ≤0.010%, and the O content is ≤0.055%; the temperature of the converter final molten steel is 1620°C~1640°C; the final slag basicity of the converter blowing is 3.0~3.5, and the FeO content of the final slag is 16%~20% and the MgO content of the final slag is 9%~15%.

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