Method for smelting gas with less slag under high-temperature molten iron condition of converter

Abstract

The invention provides a less-slag smelting gas making method under the condition of high-temperature molten iron of a converter, and relates to the field of metallurgy. The method comprises the steps that molten iron entering a furnace is analyzed, temperature and component information of the molten iron is obtained, and the molten iron entering the furnace is classified according to the temperature and component information; the temperature of the molten iron entering the furnace is higher than 1350 DEG C, and the mass content of silicon is higher than 0.4%; the scrap steel proportion is determined, and raw materials are used for converter charging; and a blowing mode and a slag former scheme are determined according to the classification result and the raw material composition, top blowing of oxygen-carbon dioxide mixed gas and bottom blowing of carbon dioxide are carried out according to the blowing mode, a solid slag former is added according to the slag former scheme, and a target steel product and recovery gas are obtained through converter smelting. According to the method provided by the invention, under the condition of reducing the converter slag, the dosage of the slag former is reduced, the steel yield is improved, and the gas recovery amount is increased, so that the converter smelting cost is reduced.

Description

Technical Field

[0001] The present application relates to the field of metallurgy, and in particular to a method for smelting gas with little slag under high-temperature molten iron conditions in a converter. Background Art

[0002] At present, the domestic steel industry is mainly based on the long process of blast furnace-converter smelting, accounting for about 90% of the total steel production. Converter steelmaking mainly uses molten iron and scrap steel as raw materials, and top-blown O2 reacts with elements such as [C], [Si], and [Mn] in the molten pool to provide heat to complete the steelmaking process. During the steelmaking process, slag-forming agents such as lime, limestone, and sintered ore need to be added to slag. The main purpose is to oxidize the impurity elements in the steel material into the slag for removal, and to control the temperature at the end of the converter smelting to be relatively stable.

[0003] The blast furnace process is the main link in the production of molten iron and determines the quality of the molten iron. In the actual production process, the ironmaking plant faces the choice between fluctuations in raw material composition and high costs, which makes the temperature and composition of the molten iron produced by the blast furnace process fluctuate greatly. When the temperature of the molten iron is high or the silicon content is high, a large amount of slag-making agent is needed to balance the heat and maintain the slag basicity, which increases the amount of converter slag, is not conducive to the smooth progress of the smelting process, and increases the splashing of the converter smelting, increases the iron loss in the slag, wastes the heat of the molten iron, and increases the cost of converter smelting.

[0004] Based on this, it is necessary to develop a new converter smelting method to solve the above problems. Summary of the invention

[0005] The purpose of the present application is to provide a method for smelting gas with little slag under high-temperature molten iron conditions in a converter to solve the above-mentioned problems.

[0006] To achieve the above objectives, this application adopts the following technical solutions:

[0007] A method for smelting gas with little slag under high-temperature molten iron conditions in a converter, comprising:

[0008] Analyze the molten iron entering the furnace to obtain the temperature and composition information of the molten iron, and classify the molten iron entering the furnace according to the temperature and composition information; the temperature of the molten iron entering the furnace is greater than 1350° C. and the silicon mass content is greater than 0.4%; the classification includes:

[0009] When the temperature of the molten iron entering the furnace is greater than 1400°C and the silicon mass content is greater than 0.8%, it is high-temperature high-silicon molten iron; when the temperature of the molten iron entering the furnace is greater than 1400°C and the silicon mass content is less than or equal to 0.8%, it is high-temperature low-silicon molten iron; when the temperature of the molten iron entering the furnace is greater than 1350°C and less than or equal to 1400°C and the silicon mass content is greater than 0.8%, it is low-temperature high-silicon molten iron;

[0010] Determine the scrap ratio and use the raw materials for converter charging;

[0011] According to the classification results and the raw material composition, the injection mode and slag-forming agent scheme are determined, top blowing of oxygen-carbon dioxide mixed gas and bottom blowing of carbon dioxide are carried out according to the injection mode, and solid slag-forming agent is added according to the slag-forming agent scheme, and the target steel product and recovered gas are obtained by converter smelting.

[0012] Preferably, the proportion of scrap steel is no higher than 20% of the total mass of the raw materials.

[0013] Preferably, in the oxygen-carbon dioxide mixture, the volume proportion of carbon dioxide is no more than 50%.

[0014] Preferably, when the molten iron entering the furnace is high-temperature high-silicon molten iron, the volume proportion of carbon dioxide in the oxygen-carbon dioxide mixed gas is 20-40%;

[0015] When the molten iron entering the furnace is high-temperature low-silicon molten iron or low-temperature high-silicon molten iron, the volume proportion of carbon dioxide in the oxygen-carbon dioxide mixed gas is not higher than 30%.

[0016] Preferably, the volume percentage of carbon dioxide in the oxygen-carbon dioxide mixture is determined by the following formula:

[0017] η(CO2)=w·(1-η 废钢 )

[0018] Wherein, η(CO2) is the volume fraction of carbon dioxide, w is the proportional constant, which is 0.32-0.36 for high-temperature high-silicon molten iron, and 0.14-0.18 for both high-temperature low-silicon molten iron and low-temperature high-silicon molten iron.

[0019] Preferably, the top blowing flow rate is 2000Nm 3 / h~10000Nm 3 / h, the bottom blowing flow rate is 120Nm 3 / h~480Nm 3 / h.

[0020] Preferably, the solid slag-forming agent comprises slaked lime, limestone and sintered ore.

[0021] Preferably, the process of determining the slag-forming agent scheme includes:

[0022] When the molten iron entering the furnace is the high-temperature high-silicon molten iron or the low-temperature high-silicon molten iron, the amount of slaked lime is adjusted based on the reduction of the amount of sintered ore, and the amount of limestone is adjusted based on the basicity, and the amount of slag is controlled.

[0023] When the molten iron entering the furnace is the high-temperature low-silicon molten iron, the amount of slaked lime is adjusted based on reducing the amount of limestone and the alkalinity, and the amount of sintered ore is adjusted with the goal of controlling the slag production.

[0024] Preferably, the binary basicity of the slag from the converter smelting is 2.1-2.8.

[0025] Preferably, the temperature of the molten iron smelted in the converter is 1350° C. to 1500° C., and the blowing time is 11 minutes to 17 minutes.

[0026] Compared with the prior art, the beneficial effects of this application include:

[0027] The present application provides a method for smelting gas with less slag under high-temperature molten iron conditions in a converter, wherein the molten iron is classified by the temperature and composition of the molten iron entering the furnace; according to the classification result and the composition of the raw materials, an appropriate amount of slag-forming agents such as lime, limestone, and sintered ore are selected for addition, and CO2 is used as a gas coolant for converter smelting, and CO2 is mixed with top blowing of O2 to achieve the control of the converter smelting temperature. CO2 as a coolant can replace part of the slag-forming agent to achieve converter smelting with less slag, reduce splashing iron loss during the smelting process, reduce iron loss in the slag at the end of smelting, improve steel recovery, and increase the amount of converter gas recovery. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope of the present application.

[0029] Figure 1 A schematic diagram of the process flow of the low-slag smelting process under high-temperature molten iron conditions in the converter provided in this application;

[0030] Figure 2 The gas supply curve of the 120t converter CO2 injection low-slag smelting gasification process;

[0031] Figure 3 This is the gas supply curve of the 210t converter CO2 injection low-slag smelting gasification process;

[0032] Figure 4 This is the gas supply curve of the 300t converter low-slag smelting gasification process with CO2 injection. DETAILED DESCRIPTION

[0033] In order to better explain the technical solution provided by this application, before the embodiments, the technical solution is first described as a whole, as follows:

[0034] A method for smelting gas with little slag under high-temperature molten iron conditions in a converter, comprising:

[0035] Analyze the molten iron entering the furnace to obtain the temperature and composition information of the molten iron, and classify the molten iron entering the furnace according to the temperature and composition information; the temperature of the molten iron entering the furnace is greater than 1350° C. and the silicon mass content is greater than 0.4%; the classification includes:

[0036] When the temperature of the molten iron entering the furnace is greater than 1400°C and the silicon mass content is greater than 0.8%, it is high-temperature high-silicon molten iron; when the temperature of the molten iron entering the furnace is greater than 1400°C and the silicon mass content is less than or equal to 0.8%, it is high-temperature low-silicon molten iron; when the temperature of the molten iron entering the furnace is greater than 1350°C and less than or equal to 1400°C and the silicon mass content is greater than 0.8%, it is low-temperature high-silicon molten iron;

[0037] Determine the scrap ratio and use the raw materials for converter charging;

[0038] According to the classification results and the raw material composition, the injection mode and slag-forming agent scheme are determined, top blowing of oxygen-carbon dioxide mixed gas and bottom blowing of carbon dioxide are carried out according to the injection mode, and solid slag-forming agent is added according to the slag-forming agent scheme, and the target steel product and recovered gas are obtained by converter smelting.

[0039] In the face of the increased slag pressure during high-temperature molten iron smelting, CO2 can be used as a gas coolant for converter smelting, which has the following advantages: (1) CO2 has reactive characteristics under high-temperature conditions in the molten pool, and can undergo oxidation reactions with elements such as [C], [Si], [Mn], and Fe(l) in the molten pool, with a reaction rate of more than 80%; (2) Compared with O2, the reaction of CO2 with elements in the molten pool will produce more CO gas, which is beneficial to the improvement of reaction kinetics and can increase the heat recovery of converter gas; (3) The reaction of CO2 with [C] and Fe(l) in the molten pool is an endothermic reaction, and the reaction with [Si] and [Mn] is a slightly exothermic reaction, and the specific heat capacity of CO2 is higher than that of O2, so it can be used as a gas coolant for converter smelting, and does not introduce impurities such as SiO2, making it a clean coolant.

[0040] It should be noted that after the blowing is completed, the furnace is shaken to discharge steel, and argon is blown from the bottom of the converter during the whole process of discharging steel, and slag blocking is done well to prevent contamination of molten steel. After discharging steel, slag splashing is carried out to protect the furnace, and the converter maintenance work is completed before the next furnace is smelted.

[0041] like Figure 1As shown, overall, the method provided by the present application can achieve the purposes of reducing the splashing iron loss during the smelting process, reducing the iron loss in the slag at the end of smelting, and improving the steel yield. Combined with the molten iron temperature and composition information and the scrap steel ratio, the CO2 mixed blowing ratio and the dosage of various slag-making agents are determined respectively to complete the converter low-slag smelting process. First, the conditions of the molten iron entering the furnace are obtained, and it is divided into three types of high-temperature molten iron, namely high-temperature high-silicon, high-temperature low-silicon and low-temperature high-silicon molten iron; the scrap steel ratio is fixed, the converter starts to be charged, and the O2-CO2 mixed blowing process is formulated based on the scrap steel ratio and the heat of the molten iron; then, a reasonable slag-making process is selected based on the silicon content of the molten iron, the scrap steel ratio and the CO2 dosage to complete the blowing process; finally, operations such as converter steel tapping and slag splashing and furnace protection are completed.

[0042] The nominal capacity of the converter is generally 35-450t.

[0043] In an optional embodiment, the proportion of scrap steel is not higher than 20% of the total mass of the raw material.

[0044] The scrap steel ratio is determined based on the actual needs of each smelting scenario and cost control.

[0045] In an optional embodiment, the volume proportion of carbon dioxide in the oxygen-carbon dioxide mixture is not higher than 50%.

[0046] In an optional embodiment, when the molten iron entering the furnace is high-temperature high-silicon molten iron, the volume proportion of carbon dioxide in the oxygen-carbon dioxide mixed gas is 20-40%;

[0047] When the molten iron entering the furnace is high-temperature low-silicon molten iron or low-temperature high-silicon molten iron, the volume proportion of carbon dioxide in the oxygen-carbon dioxide mixed gas is not higher than 30%.

[0048] In an optional embodiment, the volume percentage of carbon dioxide in the oxygen-carbon dioxide mixture is determined by the following formula:

[0049] η(CO2)=w·(1-η 废钢 )

[0050] Wherein, η(CO2) is the volume fraction of carbon dioxide, w is the proportional constant, which is 0.32-0.36 for high-temperature high-silicon molten iron, and 0.14-0.18 for both high-temperature low-silicon molten iron and low-temperature high-silicon molten iron.

[0051] In an optional embodiment, the top blowing flow rate is 2000 Nm 3 / h~10000Nm 3 / h, the bottom blowing flow rate is 120Nm 3 / h~480Nm 3 / h.

[0052] In an optional embodiment, the solid slag-forming agent includes slaked lime, limestone and sintered ore.

[0053] In an optional embodiment, the process of determining the slag-forming agent scheme includes:

[0054] When the molten iron entering the furnace is the high-temperature high-silicon molten iron or the low-temperature high-silicon molten iron, the amount of slaked lime is adjusted based on the reduction of the amount of sintered ore, and the amount of limestone is adjusted based on the basicity, and the amount of slag is controlled.

[0055] When the molten iron entering the furnace is the high-temperature low-silicon molten iron, the amount of slaked lime is adjusted based on reducing the amount of limestone and the alkalinity, and the amount of sintered ore is adjusted with the goal of controlling the slag production.

[0056] Reduce the amount of corresponding solid slagging agent to compensate for the heat consumption caused by injecting CO2.

[0057] Adding scrap steel, lime, limestone, sintered ore and injecting CO2 has a cooling effect on the molten pool. The cooling effect of different coolants and scrap steel is represented by the subscript of L added material, H 潜 represents the latent heat of melting of scrap steel, H 分解 It means that the decomposition of slag-making agent absorbs heat, H 反应 It means that CO2 absorbs heat when reacting with elements in the molten pool. The calculation formula is as follows:

[0058] L 废钢 =m 废钢 ×(c 废钢 ×(T 熔化 -T0)+H 潜 +c 钢水 ×(T 终点 -T 熔化 ))

[0059] L 造渣剂 =m 造渣剂 ×(H 分解 +c 造渣剂 ×(T 终点 -T0))

[0060] L CO2 =m CO2 ×(H 反应 +c CO2 ×(T 终点 -T0))

[0061] Taking the heat absorbed by scrap steel during melting as an equivalent value of 1, the cooling effects of slag-forming agent and CO2 relative to it are shown in Table 1.

[0062] Table 1 Cooling effect of various materials

[0063] project Scrap Steel Sintered ore limestone lime <![CDATA[CO2]]> Equivalent value 1.0 2.5～3.2 1.4～1.8 0.8～1 1.2～1.7

[0064] In an optional embodiment, the binary basicity of the slag produced by converter smelting is 2.1-2.8.

[0065] It is 0.2-0.8 lower than the conventional smelting process, and the amount of lime used in converter smelting is reduced.

[0066] In an optional embodiment, the temperature of the molten iron smelted in the converter is 1350° C. to 1500° C., and the blowing time is 11 minutes to 17 minutes.

[0067] The embodiments of the present application will be described in detail below in conjunction with specific examples, but it will be appreciated by those skilled in the art that the following examples are only used to illustrate the present application and should not be considered as limiting the scope of the present application. If specific conditions are not specified in the examples, they are carried out according to normal conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0068] First, an industrial test was conducted using molten iron produced by a blast furnace in a domestic factory as raw material, as follows:

[0069] The composition of the molten iron produced by the blast furnace of this plant is as follows in Table 2:

[0070] Table 2 Composition of molten iron produced by blast furnace

[0071] unit Minimum Maximum average value temperature ℃ 1370 1440 1405 C Wt% 4.24 5.12 4.68 Si Wt% 0.56 0.98 0.77 Mn Wt% 0.12 0.16 0.14

[0072] According to Table 2, the temperature and composition of the molten iron in the plant fluctuate greatly, including three types of high-calorie molten iron: high temperature and high silicon, high temperature and low silicon, and low temperature and high silicon. The slag-making agent and slag amount before using the method provided by the present application are shown in Table 3.

[0073] Table 3 Slag-making agent and slag amount before improvement

[0074]

[0075] According to the actual situation of the molten iron in the plant, combined with the method provided in this application, an industrial production comparison test was carried out, and the results are shown in Table 4:

[0076] Table 4 Comparison of basic data of furnaces

[0077]

[0078] As shown in Table 4, after applying the method of the present application, the amount of lime used per ton of steel is reduced by 10.55kg, the amount of limestone used is reduced by 7.63kg, and the amount of sintered ore used is reduced by 4.50kg. The output of steel slag converted to per ton of steel is reduced by 27.89kg, and the effect of reducing the amount of converter slag is significant. The total iron content in the slag is 18% on average, and the amount of metal recovered per ton of steel is increased by 5.02kg. The amount of coal gas recovered per ton of steel is increased by 7.8Nm 3 , the CO concentration in the coal gas increased by 6.22%.

[0079] In order to more fully illustrate the method provided by the present application, the following embodiments are provided:

[0080] Example 1

[0081] For a blast furnace iron water of a 120t converter in a certain factory, a low-slag smelting process under converter high-temperature iron water conditions is carried out as follows:

[0082] S1. Analyze the molten iron entering the furnace and obtain the temperature composition information of the molten iron as follows:

[0083] Molten iron temperature: 1440°C, molten iron Wt. [C]: 5.12%, molten iron Wt. [Si]: 0.98%, molten iron Wt. [Mn]: 0.16%, molten iron Wt. [P]: 0.11%, molten iron Wt. [S]: 0.020%; it was determined that the molten iron condition was high-temperature and high-silicon molten iron.

[0084] S2. The proportion of scrap steel in the steel material during smelting in this converter is 17%.

[0085] S3. According to the composition of molten iron and the structure of steel material, a top-blowing O2-CO2 smelting mode is formulated. In general, the proportion of CO2 in the mixed gas of O2 and CO2 is 28.22%. Specifically, the flow curve of the mixed gas of O2-CO2 injected into the converter is as follows: Figure 2 As shown. The top blowing CO2 flow rate is 4500Nm 3 / h~7500Nm 3 / h, the flow rate of bottom blowing CO2 is 120Nm 3 / h.

[0086] The binary basicity of converter slag making when mixed blowing O2-CO2 gas is 2.7, which is 0.2 lower than that of conventional smelting process.

[0087] The molten iron entering the furnace is determined to be high-temperature, high-silicon molten iron. The heat consumption caused by injecting CO2 is compensated by reducing the amount of sintered ore used, and the amount of sintered ore added per ton of steel is reduced by 5 to 7 kg.

[0088] S4. During the whole process of steel tapping from converter, argon gas shall be blown from the bottom of converter and slag blocking shall be done properly to prevent contamination of molten steel.

[0089] S5. Splash slag to protect the furnace and complete the converter maintenance work before proceeding to the next furnace smelting.

[0090] The amount of slag-forming agent added and the slag output during the smelting period were statistically analyzed, and the results are shown in Table 5:

[0091] Table 5 Comparison of high temperature and high silicon hot metal production

[0092]

[0093] As shown in Table 5, after the method provided in the present application is applied, the amount of lime used per ton of steel is reduced by 12.13 kg, the amount of limestone used is reduced by 3.88 kg, the amount of sintered ore used is reduced by 7.17 kg, and the output of steel slag per ton of steel is reduced by 29.87 kg. The total iron content in the slag is 17%, and the metal yield per ton of steel is increased by 5.08 kg.

[0094] According to the statistical data of the gas tank in the converter auxiliary workshop, after the application of this process, the gas recovery per ton of steel increased by 10.6Nm 3 , the CO concentration in the coal gas increased by 6.48%.

[0095] Example 2

[0096] For a blast furnace iron water of a 210t converter in a certain factory, a low-slag smelting process under converter high-temperature iron water conditions is carried out as follows:

[0097] S1. Analyze the molten iron entering the furnace and obtain the temperature composition information of the molten iron as follows:

[0098] Molten iron temperature: 1437°C, molten iron Wt. [C]: 4.68%, molten iron Wt. [Si]: 0.62%, molten iron Wt. [Mn]: 0.16%, molten iron Wt. [P]: 0.12%, molten iron Wt. [S]: 0.020%; it was determined that the molten iron condition was high-temperature, low-silicon molten iron.

[0099] S2. The proportion of scrap steel in the steel material during smelting in this converter is 13%.

[0100] S3. According to the composition of molten iron and the structure of steel material, a top-blowing O2-CO2 smelting process is formulated. The proportion of CO2 in the mixed gas of O2 and CO2 is 12.42%. Specifically, the flow curve of the mixed gas of O2-CO2 injected into the converter is as follows: Figure 3 As shown. The top blowing CO2 flow rate is 3000Nm 3 / h~6800Nm 3 / h, the flow rate of bottom blowing CO2 is 280Nm 3 / h.

[0101] The binary basicity of converter slag making when mixed blowing O2-CO2 gas is 2.7, which is 0.2 lower than that of conventional smelting process.

[0102] The molten iron entering the furnace is determined to be high-temperature, low-silicon molten iron. The heat consumption caused by injecting CO2 is compensated by reducing the amount of limestone used, and the amount of limestone added per ton of steel is reduced by 10 to 12 kg.

[0103] S4. During the whole process of steel tapping from converter, argon gas shall be blown from the bottom of converter and slag blocking shall be done properly to prevent contamination of molten steel.

[0104] S5. Splash slag to protect the furnace and complete the converter maintenance work before proceeding to the next furnace smelting.

[0105] The amount of slag-forming agent added and the slag output during the smelting period were statistically analyzed, and the results are shown in Table 6:

[0106] Table 6 Comparison of high temperature low silicon hot metal production

[0107]

[0108] As shown in Table 6, after the application of the low-slag smelting process under the condition of high-temperature hot metal in the converter, the amount of lime used per ton of steel is reduced by 5.41kg, the amount of limestone used is reduced by 11.31kg, the amount of sintered ore used is reduced by 1.82kg, and the output of steel slag per ton of steel is reduced by 14.83kg. The total iron content is 18%, and the metal yield per ton of steel is increased by 2.67kg.

[0109] According to the statistical data of the gas tank in the converter auxiliary workshop, after the application of the low-slag smelting process under the condition of high-temperature molten iron in the converter, the gas volume per ton of steel increased by 6.1Nm 3 , the CO concentration in the coal gas increased by 3.23%.

[0110] Example 3

[0111] For a blast furnace iron water of a 300t converter in a certain factory, a low-slag smelting process under converter high-temperature iron water conditions is carried out as follows:

[0112] S1. Analyze the molten iron entering the furnace and obtain the temperature composition information of the molten iron as follows:

[0113] Molten iron temperature: 1370°C, molten iron Wt. [C]: 4.65%, molten iron Wt. [Si]: 0.98%, molten iron Wt. [Mn]: 0.12%, molten iron Wt. [P]: 0.12%, molten iron Wt. [S]: 0.020%; it was determined that the molten iron condition was low-temperature, high-silicon molten iron.

[0114] S2. The proportion of scrap steel in the steel material during smelting in this converter is 15%.

[0115] S3. According to the composition of molten iron and the structure of steel material, a top-blowing O2-CO2 smelting process is formulated. The proportion of CO2 in the mixed gas of O2 and CO2 is 14.88%. Specifically, the flow curve of the mixed gas of O2-CO2 injected into the converter is as follows: Figure 4 As shown. The top blowing CO2 flow rate is 6500Nm 3 / h~9000Nm 3 / h, the flow rate of bottom blowing CO2 is 400Nm 3 / h.

[0116] The binary basicity of converter slag making when mixed blowing O2-CO2 gas is 2.8, which is 0.2 lower than that of conventional smelting process.

[0117] The molten iron entering the furnace is determined to be low-temperature, high-silicon molten iron. The heat consumption caused by injecting CO2 is compensated by reducing the amount of sintered ore used, and the amount of sintered ore added per ton of steel is reduced by 4 to 6 kg.

[0118] S4. During the whole process of steel tapping from converter, argon gas shall be blown from the bottom of converter and slag blocking shall be done properly to prevent contamination of molten steel.

[0119] S5. Splash slag to protect the furnace and complete the converter maintenance work before proceeding to the next furnace smelting.

[0120] The amount of slag-forming agent added and the slag output during the smelting period were statistically analyzed, and the results are shown in Table 7:

[0121] Table 7 Comparison of low temperature high silicon hot metal production

[0122]

[0123]

[0124] As shown in Table 7, after the application of the low-slag smelting process under the condition of high-temperature molten iron in the converter, the amount of lime used per ton of steel is reduced by 7.08kg, the amount of limestone used is reduced by 2.23kg, and the amount of sintered ore used is reduced by 5.51kg, and the output of steel slag per ton of steel is reduced by 17.93kg. The total iron content in the slag is 19%, and the metal yield per ton of steel is increased by 3.41kg.

[0125] According to the statistical data of the gas tank in the converter auxiliary workshop, after the application of the low-slag smelting process under the condition of high-temperature molten iron in the converter, the gas volume per ton of steel increased by 7.8Nm 3 , the CO concentration in the coal gas increased by 4.05%.

[0126] Comparative Example 1

[0127] In this comparative example 1, for a blast furnace iron liquid of a 120t converter of a certain factory, a conventional converter smelting process is adopted, that is, no CO2 is injected, and only slag-making agent is used to cool the iron liquid:

[0128] First, analyze the temperature and composition of the molten iron entering the furnace. The information is as follows:

[0129] Molten iron temperature: 1420°C, molten iron Wt. [C]: 4.89%, molten iron Wt. [Si]: 0.85%, molten iron Wt. [Mn]: 0.15%, molten iron Wt. [P]: 0.11%, molten iron Wt. [S]: 0.021%.

[0130] The proportion of scrap steel in the steel material during smelting in this converter is 18%.

[0131] The slag making basicity during smelting is 2.9, and lime, limestone and sintered ore are added during the smelting process to make slag.

[0132] Due to the high temperature of molten iron and the high silicon content, a large amount of slag-making agent is added. The amount of lime used per ton of steel is 48.26kg, the amount of limestone used is 32.21kg, and the amount of sintered ore used is 11.52kg.

[0133] During the smelting process, the slag layer of the converter was too thick, which caused serious splashing during the blowing process. In the middle of the smelting process, the furnace needed to be shaken and the slag was poured, and double slag operation was performed. This not only slowed down the smelting rhythm, but also caused the loss of steel materials.

[0134] According to the statistical results of converter slag in the slag car, when smelting high-temperature molten iron, the slag per ton of steel reaches 138.45 kg. The total iron content in the slag is 19%, and the metal yield per ton of steel is reduced by about 5.7 kg compared with the low-slag smelting process under the condition of converter high-temperature molten iron of the present invention.

[0135] In addition, because the high heat of the high-temperature molten iron is mainly consumed by the slag-making agent, the calorific value of the converter gas does not change significantly, resulting in a waste of heat.

[0136] Comparative Example 2

[0137] In this comparative example 2, for a blast furnace iron liquid of a 150t converter of a certain factory, a traditional converter smelting process is adopted, that is, no CO2 is injected, and only slag-making agent is used to cool the iron liquid:

[0138] First, analyze the temperature and composition of the molten iron entering the furnace. The information is as follows:

[0139] Molten iron temperature: 1380°C, molten iron Wt. [C]: 4.89%, molten iron Wt. [Si]: 0.95%, molten iron Wt. [Mn]: 0.15%, molten iron Wt. [P]: 0.11%, molten iron Wt. [S]: 0.021%.

[0140] The proportion of scrap steel in the steel material during smelting in this converter is 16%.

[0141] The slag making basicity during smelting is 2.7, and lime, limestone and sintered ore are added during the smelting process to make slag.

[0142] Due to the high temperature of molten iron and the high silicon content, a large amount of slag-making agent is added. The amount of lime used per ton of steel is 45.38kg, the amount of limestone used is 26.54kg, and the amount of sintered ore used is 14.21kg.

[0143] During the smelting process, the slag layer of the converter was too thick, and splashing was serious during the blowing process. In the middle of the smelting process, it was necessary to increase the gun position and reduce the oxygen flow, which resulted in a reduction in the calorific value of the gas recovery, and severe splashing during the smelting process, resulting in the loss of steel materials.

[0144] According to the statistical results of converter slag in the slag car, when smelting high-temperature molten iron, the slag per ton of steel reaches 156.49 kg. The total iron content in the slag is 22%, and the metal yield per ton of steel is reduced by about 8.2 kg compared with the low-slag smelting process under the condition of converter high-temperature molten iron of the present invention.

[0145] In addition, because the high heat of the high-temperature molten iron is mainly consumed by the slag-making agent and the O2 intensity of the blowing is reduced, the CO concentration in the coal gas is reduced by 2.11%, resulting in a waste of heat.

[0146] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for smelting gas with little slag under high-temperature molten iron conditions in a converter, characterized in that: include: Analyze the molten iron entering the furnace, obtain the temperature and composition information of the molten iron, and classify the molten iron entering the furnace based on the temperature and composition information; The temperature of the molten iron entering the furnace is greater than 1350°C and the silicon mass content is greater than 0.4%; the classification includes: When the temperature of the molten iron entering the furnace is greater than 1400°C and the silicon mass content is greater than 0.8%, it is high-temperature high-silicon molten iron; when the temperature of the molten iron entering the furnace is greater than 1400°C and the silicon mass content is less than or equal to 0.8%, it is high-temperature low-silicon molten iron; when the temperature of the molten iron entering the furnace is greater than 1350°C and less than or equal to 1400°C and the silicon mass content is greater than 0.8%, it is low-temperature high-silicon molten iron; Determine the scrap ratio and use the raw materials for converter charging; According to the classification results and the raw material composition, the injection mode and slag-forming agent scheme are determined, top blowing of oxygen-carbon dioxide mixed gas and bottom blowing of carbon dioxide are carried out according to the injection mode, and solid slag-forming agent is added according to the slag-forming agent scheme, and the target steel product and recovered gas are obtained by converter smelting.

2. The method for smelting gas with little slag under high temperature molten iron conditions in a converter according to claim 1, characterized in that: The proportion of scrap steel is not higher than 20% of the total mass of the raw materials.

3. The method for smelting gas with little slag under converter high temperature molten iron conditions according to claim 1, characterized in that: In the oxygen-carbon dioxide mixed gas, the volume proportion of carbon dioxide is no more than 50%.

4. The method for smelting gas with little slag under high-temperature molten iron conditions in a converter according to claim 3, characterized in that: When the molten iron entering the furnace is high-temperature high-silicon molten iron, the volume proportion of carbon dioxide in the oxygen-carbon dioxide mixed gas is 20-40%; When the molten iron entering the furnace is high-temperature low-silicon molten iron or low-temperature high-silicon molten iron, the volume proportion of carbon dioxide in the oxygen-carbon dioxide mixed gas is not higher than 30%.

5. The method for smelting gas with little slag under high temperature molten iron conditions in a converter according to claim 3, characterized in that: The volume proportion of carbon dioxide in the oxygen-carbon dioxide mixture is determined by the following formula: η(CO2)=w·(1-η 废钢 ) Wherein, η(CO2) is the volume fraction of carbon dioxide, w is the proportional constant, which is 0.32-0.36 for high-temperature high-silicon molten iron, and 0.14-0.18 for both high-temperature low-silicon molten iron and low-temperature high-silicon molten iron.

6. The method for smelting gas with little slag under high-temperature molten iron conditions in a converter according to claim 1, characterized in that: The top blowing flow rate is 2000Nm 3 / h~12000Nm 3 / h, the bottom blowing flow rate is 120Nm 3 / h~480Nm 3 / h.

7. The method for smelting gas with little slag under high-temperature molten iron conditions in a converter according to claim 1, characterized in that: The solid slag-forming agent includes slaked lime, limestone and sintered ore.

8. The method for smelting gas with little slag under high-temperature molten iron conditions in a converter according to claim 7, characterized in that: The process of determining the slagging agent scheme includes: When the molten iron entering the furnace is the high-temperature high-silicon molten iron or the low-temperature high-silicon molten iron, the amount of slaked lime is adjusted based on the reduction of the amount of sintered ore, and the amount of limestone is adjusted based on the basicity, and the amount of slag is controlled. When the molten iron entering the furnace is the high-temperature low-silicon molten iron, the amount of slaked lime is adjusted based on reducing the amount of limestone and the alkalinity, and the amount of sintered ore is adjusted with the goal of controlling the slag production.

9. The method for smelting gas with little slag under converter high temperature molten iron conditions according to claim 1, characterized in that: The binary basicity of the slag produced by the converter is 2.1-2.

8.

10. The method for smelting gas with little slag under high-temperature molten iron conditions in a converter according to any one of claims 1 to 9, characterized in that: The temperature of the molten iron smelted in the converter is 1350° C. to 1500° C., and the blowing time is 11 minutes to 17 minutes.

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