Converter steelmaking heat compensation method

Abstract

The invention discloses a converter steelmaking heat compensation method and a preparation method thereof, and the converter steelmaking heat compensation method comprises the following steps: S1, according to the components of converter steelmaking raw materials and the required target temperature T of molten steel, calculating the addition amount X of heat compensation agent graphite by using a calculation formula of the addition amount of the heat compensation agent graphite; s2, the converter steelmaking raw materials and the heat supplementing agent graphite are mixed for converter steelmaking, and molten steel is obtained; the converter steelmaking raw materials comprise molten iron, waste steel, lime and light-burned dolomite, or the converter steelmaking raw materials comprise molten iron, waste steel, lime, light-burned dolomite and auxiliary materials, and the auxiliary materials comprise pig iron blocks. According to the converter steelmaking heat compensation method, the molten steel can be accurately increased to the required target temperature according to the components of the converter steelmaking raw materials and the required target temperature T of the molten steel and the heat compensation agent graphite addition amount calculated through a specific heat compensation agent graphite addition amount calculation formula.

Description

Technical Field

[0001] The present invention relates to the field of metallurgical technology, and more specifically, to a converter steelmaking heat supplement method. Background Art

[0002] The steel industry is not only an important part of the national economy, which can promote economic growth and employment, but also provides an important basic material for the industry - steel, which can help industrial development and progress. In industry, especially in the defense industry, steel can provide necessary material support for weapons and military facilities, thereby promoting the advancement of related technologies in the defense industry. In addition, steel also plays an important role in infrastructure and can be used to build infrastructure in the fields of construction, transportation, energy, etc., specifically bridges, skyscrapers, railways, automobiles, airports, ports, power grids, etc. Steelmaking is the process of removing impurities, adjusting the composition, and making steel from raw materials such as iron ore, ferroalloys, and scrap steel through high-temperature melting and chemical reactions. It is a method of producing steel in steel. Steelmaking methods mainly include converter steelmaking, open-hearth steelmaking, and electric furnace steelmaking. Among them, converter steelmaking refers to the use of molten iron, scrap steel, and ferroalloys as the main raw materials, without the help of external energy, relying on the physical heat of the molten iron itself and the chemical reaction between the components of the molten iron to generate heat and complete the steelmaking process in the converter. Converter steelmaking has attracted attention and been promoted because it produces a wide range of steel grades, including ordinary steel and low-carbon steel, and has the advantages of short smelting cycle and relatively low energy consumption. It has now been widely used in steel companies.

[0003] The scrap steel ratio refers to the proportion of scrap steel to other raw materials (such as molten iron, pig iron, etc.) during the steelmaking process. It is an important indicator to measure the efficiency of resource utilization in steel production. A reasonable scrap steel ratio can not only reduce production costs, but also improve resource utilization and environmental benefits. In the process of actual production using converter steelmaking, steel companies often have production needs with a large scrap steel ratio in order to reduce production costs, improve resource utilization and environmental benefits, that is, a large amount of scrap steel is often used as raw material for steelmaking. In the case of actual production needs of investing a large amount of scrap steel in steelmaking to produce steel, when converter steelmaking is carried out, it is not enough to rely solely on converter heat, and supplementary heat technology is required. Supplementary heat technology refers to raising the temperature of molten steel by adding supplementary heat agents to provide the heat required for steelmaking. Accurately raising the molten steel to the required target temperature through supplementary heat agents can not only improve the production efficiency of steelmaking, but also avoid the waste of supplementary heat agents.

[0004] Therefore, it is of great significance to develop a method for supplementary heat in converter steelmaking to accurately increase the molten steel to the required target temperature through supplementary heat. Summary of the invention

[0005] The object of the present invention is to provide a converter steelmaking heat supplement method to accurately raise molten steel to a desired target temperature through a heat supplement agent.

[0006] To achieve the above object, the technical solution adopted by the present invention is:

[0007] In a first aspect, the present invention provides a method for supplementary heat in converter steelmaking, comprising the following steps:

[0008] S1. According to the composition of the converter steelmaking raw materials and the desired target temperature T of the molten steel, the amount of graphite added by the heat supplementing agent is calculated by the calculation formula of the amount of graphite added by the heat supplementing agent X;

[0009] S2. Mixing converter steelmaking raw materials and heat supplement graphite for converter steelmaking to obtain molten steel;

[0010] The components of the converter steelmaking raw materials include molten iron, scrap steel, lime, and light-burned dolomite, or the components of the converter steelmaking raw materials include molten iron, scrap steel, lime, light-burned dolomite and auxiliary materials, and the auxiliary materials include pig iron blocks;

[0011] The calculation formula for the amount of graphite added as a heat supplement is:

[0012] X=(TY) / 26 Formula 1;

[0013] Y=Z 铁水 +Z 废钢 +Z 生铁块 +Z 石灰和轻烧白云石 +1586.16 Formula 2;

[0014] Z 铁水 =(T0-1396)×0.8+(A 碳 -0.0457)×3800+(A 硅 -0.0039)×18100 Formula 3;

[0015] Z 废钢 =(M 废钢 -35.6)×(-9.5) Formula 4;

[0016] Z 生铁块 =(M 生铁块 -6.5)×(-6) Formula 5;

[0017] Z 石灰和轻烧白云石 =(M 石灰 +M 轻烧白云石 -6.582)×(-10) Formula 6;

[0018] in:

[0019] X is the amount of graphite added as a heat supplement, unit: ton (t);

[0020] T is the desired target temperature of the molten steel, in °C;

[0021] T0 is the temperature of molten iron in the converter steelmaking raw material, unit: °C, and T>T0;

[0022] A 碳 is the weight percentage of carbon in the molten iron, the raw material for converter steelmaking, and A 碳 >0;

[0023] A 硅 is the weight percentage of silicon in the molten iron, the raw material for converter steelmaking, and A 硅 >0;

[0024] M 废钢 is the amount of scrap steel added to the converter steelmaking raw materials, unit: tons (t), and M 废钢 >0;

[0025] M 生铁块 is the amount of pig iron added to the converter steelmaking raw material, unit: ton (t), and M 生铁块 >0; when M 生铁块 = 0, Z 生铁块 =0;

[0026] M 石灰 is the amount of lime added to the converter steelmaking raw material, unit: ton (t), M 轻烧白云石 is the amount of light-burned dolomite added to the converter steelmaking raw material, unit: tons (t), and M 石灰 +M 轻烧白云石 >0.

[0027] Preferably, the calorific value (Qgr,d) of the graphite-like material is ≥22 MJ / kg, and the dry-basis fixed carbon content of the graphite-like material is ≥72 wt%.

[0028] More preferably, the calorific value (Qgr,d) of the graphite-like material is 22-26 MJ / kg, and the dry-basis fixed carbon content of the graphite-like material is 72-77 wt%.

[0029] In the present invention, the dry sulfur (St, d) content, water (Mt) content, particle size and other parameters of the graphite-like material have almost no influence on the calculation formula of the addition amount of the graphite-like material as the heat supplement.

[0030] Preferably, the dry sulfur (St,d) content of the graphite-like material is ≤ 0.6 wt% (ie, 0-0.6 wt%).

[0031] More preferably, the dry sulfur (St,d) content of the graphite-like material is 0-0.4 wt %, specifically 0.2-0.4 wt %.

[0032] Preferably, the moisture content (Mt) of the graphite-like material is ≤ 0.8 wt % (ie, 0-0.8 wt %).

[0033] More preferably, the moisture content (Mt) of the graphite-like material is 0-0.3 wt %, specifically 0.1-0.3 wt %.

[0034] Preferably, the graphite-like particle size is 20-60 mm.

[0035] In the present invention, the method for measuring the graphite-like calorific value (Qgr, d) refers to GB / T 213-2008 "Method for determining the calorific value of coal".

[0036] In the present invention, the method for measuring the dry-basis fixed carbon content of the graphite-like substance refers to GB / T 476-2008 "Determination of carbon and hydrogen content in coal".

[0037] In the present invention, the method for measuring the dry sulfur (St, d) of the graphite-like material refers to GB / T 31391-2015 "Determination of total sulfur content in coal by infrared spectrometry".

[0038] In the present invention, the method for measuring the moisture content (Mt) of the graphite-like substance refers to GB / T 212-2008 "Industrial Analysis Methods for Coal".

[0039] Preferably, the molten iron comprises the following components in percentage by weight:

[0040] C 4.00-5.90wt%, Si 0.30-0.70wt%, Mn 0.20-0.65wt%, P 0.090-0.150wt%, S 0.02-0.06wt%, and the balance is Fe and inevitable impurities.

[0041] Preferably, the weight ratio of the molten iron to the scrap steel is (50-90):(10-50), specifically (60-80):(20-40).

[0042] Scrap steel, pig iron, lime and light-burned dolomite commonly used in the art can be used in the present invention.

[0043] Preferably, the weight of the molten iron is ≤150 tons, specifically ≤130 tons.

[0044] More preferably, the weight of the molten iron is 90-120 tons.

[0045] More preferably, the weight of the molten iron is 90 tons, 90.5 tons, 91 tons, 91.5 tons, 92 tons, 92.5 tons, 93 tons, 93.5 tons, 94 tons, 94.5 tons, 95 tons, 95.5 tons, 96 tons, 96.5 tons, 97 tons, 97.5 tons, 98 tons, 98.5 tons, 99 tons, 99.5 tons, 100 tons, 100.5 tons, 101 tons, 101.5 tons, 102 tons, 102.5 tons, 103 tons, 103.5 tons, 104 tons, 104.5 tons, 105 tons, 105.5 tons, The range value of one or any two of 106 tons, 106.5 tons, 107 tons, 107.5 tons, 108 tons, 108.5 tons, 109 tons, 109.5 tons, 110 tons, 110.5 tons, 111 tons, 111.5 tons, 112 tons, 112.5 tons, 113 tons, 113.5 tons, 114 tons, 114.5 tons, 115 tons, 115.5 tons, 116 tons, 116.5 tons, 117 tons, 117.5 tons, 118 tons, 118.5 tons, 119 tons, 119.5 tons, and 120 tons.

[0046] Preferably, the desired target temperature T of the molten steel is 1500-1650°C, specifically 1550-1620°C.

[0047] More preferably, the desired target temperature T of the molten steel is 1580-1605°C.

[0048] Preferably, the temperature T0 of the molten iron in the converter steelmaking raw material is 1300-1480°C, specifically 1305-1450°C.

[0049] More preferably, the desired target temperature T of the molten steel is 1308-1448°C.

[0050] Preferably, the amount of scrap steel added (M 废钢 ) is 25-55 tons, specifically 30-50 tons.

[0051] More preferably, the amount of scrap steel added (M 废钢 ) is 32-47 tons.

[0052] Preferably, the amount of pig iron added (M 生铁块 ) is 1-15 tons, specifically 2-10 tons.

[0053] More preferably, the amount of pig iron added (M 生铁块 ) is 3-8 tons, specifically 3.5-7.7 tons.

[0054] Preferably, the addition amount of lime and light-burned dolomite (M 石灰 +M 轻烧白云石) is 1-15 tons, specifically 2-10 tons.

[0055] More preferably, the addition amount of lime and light-burned dolomite (M 石灰 +M 轻烧白云石 ) is 5-8 tons, specifically 5.5-7.8 tons.

[0056] Preferably, when the addition amount X of the heat supplementary graphite is ≤1.5 tons, step S2 specifically comprises: first adding the heat supplementary graphite, then adding the converter steelmaking raw materials, and blowing to obtain molten steel at the target temperature T.

[0057] More preferably, the blowing is top blowing oxygen and bottom blowing stirring gas, and the amount of top blowing oxygen is 6000-6750Nm 3 , the supply intensity of the bottom blowing stirring gas is 200-500Nm 3 / h.

[0058] More preferably, the stirring gas is at least one of argon and nitrogen.

[0059] More preferably, the oxygen blowing time of the blowing is 12-15 minutes.

[0060] Preferably, when the addition amount X of the heat supplementary graphite is greater than 1.5 tons and less than or equal to 3 tons, step S2 is specifically as follows: first add 1.5 tons of heat supplementary graphite, then add converter steelmaking raw materials, blow, and add the remaining heat supplementary graphite within 2-4 minutes after the start of blowing to obtain molten steel.

[0061] More preferably, the blowing is top blowing oxygen and bottom blowing stirring gas, and the amount of top blowing oxygen is 6000-6750Nm 3 , the supply intensity of the bottom blowing stirring gas is 200-500Nm 3 / h.

[0062] More preferably, the stirring gas is at least one of argon and nitrogen.

[0063] More preferably, the oxygen blowing time of the blowing is 12-15 minutes.

[0064] Preferably, when the addition amount X of the heat supplementary graphite is greater than 3 tons, step S2 is specifically as follows: first add 2.0 tons of heat supplementary graphite, then add converter steelmaking raw materials, blow, and add the remaining heat supplementary graphite within 2-11 minutes after the start of blowing to obtain molten steel.

[0065] More preferably, the blowing is top blowing oxygen and bottom blowing stirring gas, and the amount of top blowing oxygen is 6000-6750Nm 3 , the supply intensity of the bottom blowing stirring gas is 200-500Nm 3 / h.

[0066] More preferably, the stirring gas is at least one of argon and nitrogen.

[0067] More preferably, the oxygen blowing time of the blowing is 12-15 minutes.

[0068] In step S2 of the present invention, 11 minutes after the start of the blowing of the converter steelmaking, it is forbidden to add the heat supplementary agent such as graphite, so as to prevent carbon return during the steelmaking process.

[0069] Compared with the prior art, the present invention has the following beneficial effects:

[0070] The converter steelmaking heat supplement method of the present invention can accurately increase the molten steel to the required target temperature T according to the composition of the converter steelmaking raw materials and the required target temperature T of the molten steel, and the amount of heat supplementary graphite added calculated by a specific heat supplementary graphite addition calculation formula.

[0071] The converter steelmaking heat supplementation method of the present invention also has significant economic benefits and convenient operation. By accurately controlling the temperature of the converter smelting end point, the method can achieve a smelting process with a high scrap steel ratio. At the same time, since the heat supplementation method does not require the addition of additional processes or equipment, it does not bring additional process costs, making the entire steelmaking process more economical and efficient. DETAILED DESCRIPTION

[0072] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0073] The experimental methods in the following examples without specifying specific conditions are generally carried out according to conventional conditions in the art or according to conditions recommended by the manufacturer; the raw materials, reagents, etc. used, unless otherwise specified, are all raw materials and reagents that can be obtained from commercial channels such as conventional markets.

[0074] In the present invention, the method for measuring the graphite-like calorific value (Qgr, d) refers to GB / T 213-2008 "Method for determining the calorific value of coal".

[0075] In the present invention, the method for measuring the dry-basis fixed carbon content of the graphite-like substance refers to GB / T 476-2008 "Determination of carbon and hydrogen content in coal".

[0076] In the present invention, the method for measuring the dry sulfur (St, d) of the graphite-like material refers to GB / T 31391-2015 "Determination of total sulfur content in coal by infrared spectrometry".

[0077] In the present invention, the method for measuring the moisture content (Mt) of the graphite-like substance refers to GB / T 212-2008 "Industrial Analysis Methods for Coal".

[0078] In the present invention, the calculation formula for the amount of graphite added as a heat supplement is:

[0079] X=(TY) / 26 Formula 1;

[0080] Y=Z 铁水 +Z 废钢 +Z 生铁块 +Z 石灰和轻烧白云石 +1586.16 Formula 2;

[0081] Z 铁水 =(T0-1396)×0.8+(A 碳 -0.0457)×3800+(A 硅 -0.0039)×18100 Formula 3;

[0082] Z 废钢 =(M 废钢 -35.6)×(-9.5) Formula 4;

[0083] Z 生铁块 =(M 生铁块 -6.5)×(-6) Formula 5;

[0084] Z 石灰和轻烧白云石 =(M 石灰 +M 轻烧白云石 -6.582)×(-10) Formula 6;

[0085] in:

[0086] X is the amount of graphite added as a heat supplement, unit: ton (t);

[0087] T is the desired target temperature of the molten steel, in °C;

[0088] T0 is the temperature of molten iron in the converter steelmaking raw material, unit: °C, and T>T0;

[0089] A 碳 is the weight percentage of carbon in the molten iron, the raw material for converter steelmaking, and A 碳 >0;

[0090] A 硅 is the weight percentage of silicon in the molten iron, the raw material for converter steelmaking, and A 硅 >0;

[0091] M 废钢 is the amount of scrap steel added to the converter steelmaking raw materials, unit: tons (t), and M 废钢 >0;

[0092] M 生铁块 is the amount of pig iron added to the converter steelmaking raw material, unit: ton (t), and M生铁块 >0; when M 生铁块 = 0, Z 生铁块 =0;

[0093] M 石灰 is the amount of lime added to the converter steelmaking raw material, unit: ton (t), M 轻烧白云石 is the amount of light-burned dolomite added to the converter steelmaking raw material, unit: tons (t), and M 石灰 +M 轻烧白云石 >0.

[0094] Example 1

[0095] This embodiment provides a converter steelmaking heat supplement method, comprising the following steps:

[0096] S1. According to the composition of the converter steelmaking raw materials and the required target temperature of the molten steel T = 1605 ° C, the addition amount of the heat supplementary graphite X is calculated using the calculation formula for the addition amount of the heat supplementary graphite, and it is found that X = 0.97 tons, as follows:

[0097] The components of the converter steelmaking raw materials include: 106 tons of molten iron, 37.2 tons of scrap steel, 7.7 tons of pig iron, and 7.721 tons of lime and light-burned dolomite (including 5.171 tons of lime and 2.550 tons of light-burned dolomite);

[0098] The temperature T0 of the molten iron is 1448° C. The molten iron includes the following components in percentage by weight:

[0099] C 4.53wt%, Si 0.32wt%, Mn 0.28wt%, P 0.1401%, S 0.0467wt%, the balance is Fe and unavoidable impurities;

[0100] The weight ratio of the molten iron to the scrap steel is 106:37.2=66.25:23.25;

[0101] The calorific value (Qgr, d) of the graphite-like material is 24 MJ / kg, the dry basis fixed carbon content of the graphite-like material is 75 wt %, the dry basis sulfur (St, d) content of the graphite-like material is 0.25 wt %, the moisture (Mt) content of the graphite-like material is 0.17 wt %, and the particle size of the graphite-like material is 20-60 mm;

[0102] According to the calculation formula of the amount of graphite added as a heat supplement, in this embodiment, the amount of graphite added as a heat supplement is X = [T - (Z 铁水 +Z 废钢 +Z 生铁块 +Z 石灰和轻烧白云石+1586.16)] / 26={1605-[(1448-1396)×0.8+(0.0453-0.0457)×3800+(0.0032-0.0039)×18100+(37.2-35.6)×(-9.5)+(7.7-6.5)×(-6)+(7.721-6.582)×(-10)+1586.16)]} / 26=0.97 tons;

[0103] S2. Mixing converter steelmaking raw materials and heat supplement graphite for converter steelmaking to obtain molten steel, as follows:

[0104] First, a heat supplement type graphite (the addition amount X=0.97 tons) is added to a top and bottom double-blown converter with a loading amount of 150 tons, and then a converter steelmaking raw material is added, and the steel is blown to obtain molten steel;

[0105] The blowing process is top blowing oxygen and bottom blowing stirring gas, and the amount of top blowing oxygen is 6200Nm 3 The supply intensity of the bottom blowing stirring gas is 280Nm 3 , the stirring gas is argon, and the blowing time of the blowing is 13 minutes;

[0106] The actual temperature of the molten steel obtained in this embodiment is 1604°C, which is only -0.06% different from the target temperature T=1605°C = (actual temperature of the molten steel-required target temperature of the molten steel) / required target temperature of the molten steel×100%.

[0107] Example 2

[0108] This embodiment provides a converter steelmaking heat supplement method, comprising the following steps:

[0109] S1. According to the composition of the converter steelmaking raw materials and the required target temperature of the molten steel T = 1605 ° C, the addition amount of the heat supplementary graphite X is calculated using the calculation formula for the addition amount of the heat supplementary graphite, and it is found that X = 1.82 tons, as follows:

[0110] The components of the converter steelmaking raw materials include: 109.4 tons of molten iron, 41.6 tons of scrap steel, 3.6 tons of pig iron, and 6.897 tons of lime and light-burned dolomite (including 3.941 tons of lime and 2.956 tons of light-burned dolomite);

[0111] The temperature T0 of the molten iron is 1414° C. The molten iron includes the following components in percentage by weight:

[0112] C 4.66wt%, Si 0.37wt%, Mn 0.40wt%, P 0.1393wt%, S 0.0382wt%, the balance is Fe and unavoidable impurities;

[0113] The weight ratio of the molten iron to the scrap steel is 109.4:41.6=68.375:26;

[0114] The calorific value (Qgr, d) of the graphite-like material is 25.4 MJ / kg, the dry basis fixed carbon content of the graphite-like material is 76.5 wt %, the dry basis sulfur (St, d) content of the graphite-like material is 0.3 wt %, the moisture (Mt) content of the graphite-like material is 0.6 wt %, and the particle size of the graphite-like material is 20-60 mm;

[0115] According to the calculation formula of the amount of graphite added as a heat supplement, in this embodiment, the amount of graphite added as a heat supplement is X = [T - (Z 铁水 +Z 废钢 +Z 生铁块 +Z 石灰和轻烧白云石 +1586.16)] / 26={1605-[(1414-1396)×0.8+(0.0466-0.0457)×3800+(0.0037-0.0039)×18100+(41.6-35.6)×(-9.5)+(3.6-6.5)×(-6)+(6.897-6.582)×(-10)+1586.16)]} / 26=1.82 tons;

[0116] S2. Mixing converter steelmaking raw materials and heat supplement graphite (the amount of which added is X = 1.82 tons) for converter steelmaking to obtain molten steel, as follows:

[0117] First, 1.5 tons of graphite as a heat supplement is added to a 150-ton top and bottom double-blown converter, and then the converter steelmaking raw materials are added, and the steel is blown, and the remaining graphite as a heat supplement is added within 2-4 minutes after the start of the blowing to obtain molten steel;

[0118] The blowing process is top blowing oxygen and bottom blowing stirring gas, and the amount of top blowing oxygen is 6575Nm 3 , the supply intensity of the bottom blowing stirring gas is 300Nm 3 / h, the stirring gas is argon, and the blowing time of the blowing is 13.6min;

[0119] The actual temperature of the molten steel obtained in this embodiment is 1610°C, which is only 0.31% different from the target temperature T=1605°C = (actual temperature of the molten steel-required target temperature of the molten steel) / required target temperature of the molten steel×100%.

[0120] Example 3

[0121] This embodiment provides a converter steelmaking heat supplement method, comprising the following steps:

[0122] S1. According to the composition of the converter steelmaking raw materials and the required target temperature of the molten steel T = 1565 ° C, the addition amount of the heat supplementary graphite X is calculated using the calculation formula for the addition amount of the heat supplementary graphite, and it is found that X = 3.78 tons, as follows:

[0123] The components of the converter steelmaking raw materials include: 110 tons of molten iron, 46.1 tons of scrap steel, 3.6 tons of pig iron, and 5.887 tons of lime and light-burned dolomite (including 3.307 tons of lime and 2.580 tons of light-burned dolomite);

[0124] The temperature T0 of the molten iron is 1363° C. The molten iron includes the following components in percentage by weight:

[0125] C 4.13wt%, Si 0.38wt%, Mn 0.21wt%, P 0.1404wt%, S 0.0359wt%, the balance is Fe and unavoidable impurities;

[0126] The weight ratio of the molten iron to the scrap steel is 110:46.1=68.75:28.8125;

[0127] The calorific value (Qgr, d) of the graphite-like material is 24.5 MJ / kg, the dry basis fixed carbon content of the graphite-like material is 75.3 wt %, the dry basis sulfur (St, d) content of the graphite-like material is 0.3 wt %, the moisture (Mt) content of the graphite-like material is 0.5 wt %, and the particle size of the graphite-like material is 20-60 mm;

[0128] According to the calculation formula of the amount of graphite added as a heat supplement, in this embodiment, the amount of graphite added as a heat supplement is X = [T - (Z 铁水 +Z 废钢 +Z 生铁块 +Z 石灰和轻烧白云石 +1586.16)] / 26={1565-[(1363-1396)×0.8+(0.0413-0.0457)×3800+(0.0038-0.0039)×18100+(46.1-35.6)×(-9.5)+(3.6-6.5)×(-6)+(5.887-6.582)×(-10)+1586.16)]} / 26=3.78 tons;

[0129] S2. Mixing converter steelmaking raw materials and heat supplement graphite (the amount of which added is X = 3.78 tons) for converter steelmaking to obtain molten steel, as follows:

[0130] First, 2.0 tons of graphite as a heat supplement is added to a top and bottom double-blown converter with a loading capacity of 150 tons, and then the converter steelmaking raw materials are added, and the steel is blown, and the remaining graphite as a heat supplement is added within 2-5 minutes after the start of the blowing to obtain molten steel;

[0131] The blowing process is top blowing oxygen and bottom blowing stirring gas, and the amount of top blowing oxygen is 6500Nm 3 The supply intensity of the bottom blowing stirring gas is 420Nm 3 / h, the stirring gas is argon, and the blowing time of the blowing is 14.8min;

[0132] The actual temperature of the molten steel obtained in this embodiment is 1555°C, which is only -0.64% different from the target temperature T=1565°C = (actual temperature of the molten steel-required target temperature of the molten steel) / required target temperature of the molten steel×100%.

[0133] Example 4

[0134] This embodiment provides a converter steelmaking heat supplement method, comprising the following steps:

[0135] S1. According to the composition of the converter steelmaking raw materials and the required target temperature of the molten steel T = 1580 ° C, the addition amount of the heat supplementary graphite X is calculated using the calculation formula for the addition amount of the heat supplementary graphite, and it is found that X = 1.23 tons, as follows:

[0136] The components of the converter steelmaking raw materials include: 103.6 tons of molten iron, 33 tons of scrap steel, 7.8 tons of pig iron, and 7.792 tons of lime and light-burned dolomite (including 5.109 tons of lime and 2.683 tons of light-burned dolomite);

[0137] The temperature T0 of the molten iron is 1308° C. The molten iron includes the following components in percentage by weight:

[0138] C 4.24wt%, Si 0.60wt%, Mn 0.25wt%, P 0.1439wt%, S 0.0518wt%, the balance is Fe and unavoidable impurities;

[0139] The weight ratio of the molten iron to the scrap steel is 103.6:33=64.75:20.625;

[0140] The calorific value (Qgr, d) of the graphite-like material is 24.3 MJ / kg, the dry basis fixed carbon content of the graphite-like material is 74.6 wt %, the dry basis sulfur (St, d) content of the graphite-like material is 0.2 wt %, the moisture (Mt) content of the graphite-like material is 0.8 wt %, and the particle size of the graphite-like material is 20-60 mm;

[0141] According to the calculation formula of the amount of graphite added as a heat supplement, in this embodiment, the amount of graphite added as a heat supplement is X = [T - (Z 铁水 +Z 废钢 +Z 生铁块 +Z石灰和轻烧白云石 +1586.16)] / 26={1580-[(1308-1396)×0.8+(0.0424-0.0457)×3800+(0.0060-0.0039)×18100+(33-35.6)×(-9.5)+(7.8-6.5)×(-6)+(7.792-6.582)×(-10)+1586.16)]} / 26=1.23 tons;

[0142] S2. Mixing converter steelmaking raw materials and heat supplement graphite (the amount of which added is X = 1.23 tons) for converter steelmaking to obtain molten steel, as follows:

[0143] First, a heat supplement type graphite (the addition amount X=1.23 tons) is added to a top and bottom double-blown converter with a loading amount of 150 tons, and then the converter steelmaking raw materials are added and blown to obtain molten steel;

[0144] The blowing process is top blowing oxygen and bottom blowing stirring gas, and the amount of top blowing oxygen is 6438Nm 3 The supply intensity of the bottom blowing stirring gas is 390Nm 3 / h, the stirring gas is argon, and the blowing time of the blowing is 13.3min;

[0145] The actual temperature of the molten steel obtained in this embodiment is 1571°C, which is only -0.57% different from the target temperature T=1580°C = (actual temperature of the molten steel-required target temperature of the molten steel) / required target temperature of the molten steel×100%.

[0146] Example 5

[0147] This embodiment provides a converter steelmaking heat supplement method, comprising the following steps:

[0148] S1. According to the composition of the converter steelmaking raw materials and the required target temperature of the molten steel T = 1580 ° C, the addition amount of the heat supplementary graphite X is calculated using the calculation formula for the addition amount of the heat supplementary graphite, and it is found that X = 0.95 tons, as follows:

[0149] The components of the converter steelmaking raw materials include: 111 tons of molten iron, 32.3 tons of scrap steel, 7.7 tons of pig iron, and 6.451 tons of lime and light-burned dolomite (including 4.018 tons of lime and 2.433 tons of light-burned dolomite);

[0150] The temperature T0 of the molten iron is 1318° C., and the molten iron includes the following components in percentage by weight:

[0151] C 5.03wt%, Si 0.31wt%, Mn 0.20wt%, P 0.1138wt%, S 0.0425wt%, the balance is Fe and unavoidable impurities;

[0152] The weight ratio of the molten iron to the scrap steel is 111:32.3=77.46:22.54;

[0153] The calorific value (Qgr, d) of the graphite-like material is 23.9 MJ / kg, the dry basis fixed carbon content of the graphite-like material is 76.3 wt %, the dry basis sulfur (St, d) content of the graphite-like material is 0.3 wt %, the moisture (Mt) content of the graphite-like material is 0.8 wt %, and the particle size of the graphite-like material is 20-60 mm;

[0154] According to the calculation formula of the amount of graphite added as a heat supplement, in this embodiment, the amount of graphite added as a heat supplement is X = [T - (Z 铁水 +Z 废钢 +Z 生铁块 +Z 石灰和轻烧白云石 +1586.16)] / 26={1580-[(1318-1396)×0.8+(0.0503-0.0457)×3800+(0.0031-0.0039)×18100+(32.3-35.6)×(-9.5)+(7.7-6.5)×(-6)+(6.451-6.582)×(-10)+1586.16)]} / 26=0.95 tons;

[0155] S2. Mixing converter steelmaking raw materials and heat supplement graphite (the amount of which added is X = 0.95 tons) for converter steelmaking to obtain molten steel, as follows:

[0156] First, a heat supplement type graphite (the addition amount X=0.95 tons) is added to a top and bottom double-blown converter with a loading amount of 150 tons, and then the converter steelmaking raw materials are added and blown to obtain molten steel;

[0157] The blowing process is top blowing oxygen and bottom blowing stirring gas, and the amount of top blowing oxygen is 6366Nm 3 The supply intensity of the bottom blowing stirring gas is 390Nm 3 / h, the stirring gas is argon, and the blowing time of the blowing is 13.5min;

[0158] The actual temperature of the molten steel obtained in this embodiment is 1583°C, which is only 0.19% different from the target temperature T=1580°C = (actual temperature of the molten steel-required target temperature of the molten steel) / required target temperature of the molten steel×100%.

[0159] Example 6

[0160] This embodiment provides a converter steelmaking heat supplement method, comprising the following steps:

[0161] S1. According to the composition of the converter steelmaking raw materials and the required target temperature of the molten steel T = 1580 ° C, the addition amount of the heat supplementary graphite X is calculated using the calculation formula for the addition amount of the heat supplementary graphite, and it is found that X = 1.79 tons, as follows:

[0162] The components of the converter steelmaking raw materials include: 115.5 tons of molten iron, 40.3 tons of scrap steel, and 6.730 tons of lime and light-burned dolomite (including 4.164 tons of lime and 2.566 tons of light-burned dolomite);

[0163] The temperature T0 of the molten iron is 1380° C. The molten iron includes the following components in percentage by weight:

[0164] C 4.53wt%, Si 0.41wt%, Mn 0.21wt%, P 0.1396wt%, S 0.0430wt%, the balance is Fe and unavoidable impurities;

[0165] The weight ratio of the molten iron to the scrap steel is 115.5:40.3=72.1875:25.1875;

[0166] The calorific value (Qgr, d) of the graphite-like material is 25.2 MJ / kg, the dry basis fixed carbon content of the graphite-like material is 75.3 wt %, the dry basis sulfur (St, d) content of the graphite-like material is 0.2 wt %, the moisture (Mt) content of the graphite-like material is 0.8 wt %, and the particle size of the graphite-like material is 20-60 mm;

[0167] According to the calculation formula of the amount of graphite added as a heat supplement, in this embodiment, the amount of graphite added as a heat supplement is X = [T - (Z 铁水 +Z 废钢 +Z 石灰和轻烧白云石 +1586.16)] / 26={1580-[(1380-1396)×0.8+(0.0453-0.0457)×3800+(0.0041-0.0039)×18100+(40.3-35.6)×(-9.5)+(6.730-6.582)×(-10)+1586.16)]} / 26=1.79 tons;

[0168] S2. Mixing converter steelmaking raw materials and heat supplement graphite (the amount of which added is X = 1.79 tons) for converter steelmaking to obtain molten steel, as follows:

[0169] First, 1.5 tons of graphite as a heat supplement is added to a 150-ton top and bottom double-blown converter, and then the converter steelmaking raw materials are added, and the steel is blown, and the remaining graphite as a heat supplement is added within 2-4 minutes after the start of the blowing to obtain molten steel;

[0170] The blowing process is top blowing oxygen and bottom blowing stirring gas, and the amount of top blowing oxygen is 6450 Nm 3 The supply intensity of the bottom blowing stirring gas is 390Nm 3 / h, the stirring gas is argon, and the blowing time of the blowing is 13.1min;

[0171] The actual temperature of the molten steel obtained in this embodiment is 1585°C, which is only 0.32% different from the target temperature T=1580°C = (actual temperature of the molten steel-required target temperature of the molten steel) / required target temperature of the molten steel×100%.

[0172] It can be seen from Examples 1-6 that the converter steelmaking heat supplement method of the present invention can accurately increase the molten steel to the desired target temperature T by calculating the amount of heat supplementary graphite added based on the composition of the converter steelmaking raw materials and the desired target temperature T of the molten steel, and by using a specific heat supplementary graphite addition calculation formula.

[0173] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A method for supplementary heat in converter steelmaking, characterized in that: The steps include: S1. According to the composition of the converter steelmaking raw materials and the desired target temperature T of the molten steel, the amount of graphite added by the heat supplementing agent is calculated by the calculation formula of the amount of graphite added by the heat supplementing agent X; S2. Mixing converter steelmaking raw materials and heat supplement graphite for converter steelmaking to obtain molten steel; The components of the converter steelmaking raw materials include molten iron, scrap steel, lime, and light-burned dolomite, or the components of the converter steelmaking raw materials include molten iron, scrap steel, lime, light-burned dolomite and auxiliary materials, and the auxiliary materials include pig iron blocks; The calculation formula for the amount of graphite added as a heat supplement is: X=(TY) / 26 Formula 1; Y = Z 铁水 + Z 废钢 + Z 生铁块 + Z 石灰和轻烧白云石 + 1586.16 Formula 2; Z 铁水 =(T0-1396)×0.8+(A 碳 -0.0457)×3800+(A 硅 -0.0039)×18100 Formula 3; Z 废钢 =(M 废钢 -35.6)×(-9.5) Formula 4; Z 生铁块 =(M 生铁块 -6.5)×(-6) Formula 5; Z 石灰和轻烧白云石 =(M 石灰 +M 轻烧白云石 -6.582)×(-10) Formula 6; in: X is the amount of graphite added as a heat supplement, unit: tons; T is the desired target temperature of the molten steel, in °C; T0 is the temperature of molten iron in the converter steelmaking raw material, unit: °C, and T>T0; A 碳 is the weight percentage of carbon in the molten iron, the raw material for converter steelmaking, and A 碳 >0; A 硅 is the weight percentage of silicon in the molten iron, the raw material for converter steelmaking, and A 硅 >0; M 废钢 is the amount of scrap steel added to the converter steelmaking raw materials, unit: tons, and M 废钢 >0; M 生铁块 is the amount of pig iron added to the converter steelmaking raw material, unit: tons, and M 生铁块 >0; when M 生铁块 = 0, Z 生铁块 =0; M 石灰 The amount of lime added to the converter steelmaking raw material, unit: tons, M 轻烧白云石 is the amount of light-burned dolomite added to the converter steelmaking raw material, unit: tons, and M 石灰 +M 轻烧白云石 >0.

2. The converter steelmaking heat supplementation method according to claim 1, characterized in that: The calorific value of the graphite-like material is ≥22 MJ / kg, and the dry-basis fixed carbon content of the graphite-like material is ≥72 wt%.

3. The converter steelmaking heat supplementation method according to claim 2, characterized in that: The calorific value of the graphite-like material is 22-26 MJ / kg, and the dry-basis fixed carbon content of the graphite-like material is 72-77 wt %.

4. The converter steelmaking heat supplementation method according to claim 1, characterized in that: Including at least one of the following (1)-(3): (1) The dry sulfur content of the graphite-like material is ≤0.6wt%; (2) The moisture content of the graphite-like material is ≤0.8wt%; (3) The particle size of the graphite-like material is 20-60 mm.

5. The converter steelmaking supplementary heat method according to claim 1, characterized in that: The molten iron comprises the following components in percentage by weight: C 4.00-5.90wt%, Si 0.30-0.70wt%, Mn 0.20-0.65wt%, P 0.090-0.150wt%, S 0.02-0.06wt%, and the balance is Fe and inevitable impurities.

6. The converter steelmaking supplementary heat method according to claim 1, characterized in that: The weight ratio of the molten iron to the scrap steel is (50-90):(10-50).

7. The converter steelmaking supplementary heat method according to claim 1, characterized in that: The weight of the molten iron is ≤150 tons.

8. The converter steelmaking supplementary heat method according to claim 1, characterized in that: When the addition amount X of the heat supplementary graphite is ≤1.5 tons, step S2 specifically includes: firstly adding the heat supplementary graphite, then adding the converter steelmaking raw materials, and blowing to obtain molten steel with the target temperature T.

9. The converter steelmaking supplementary heat method according to claim 1, characterized in that: When the addition amount X of the heat supplementary graphite is greater than 1.5 tons and less than or equal to 3 tons, step S2 is specifically as follows: first add 1.5 tons of heat supplementary graphite, then add converter steelmaking raw materials, blow, and add the remaining heat supplementary graphite within 2-4 minutes after the start of blowing to obtain molten steel.

10. The converter steelmaking supplementary heat method according to claim 1, characterized in that: When the addition amount X of the heat supplementary graphite is greater than 3 tons, step S2 is specifically as follows: first add 2.0 tons of heat supplementary graphite, then add converter steelmaking raw materials, blow, and add the remaining heat supplementary graphite within 2-11 minutes after the start of blowing to obtain molten steel.