A method for determining the scrap content in converter metal charge under insufficient heat conditions.

Abstract

This invention discloses a method for determining the scrap steel content in converter metal charge under insufficient heat conditions. It primarily addresses the technical problems of being unable to assess the benefits of increasing scrap steel usage in the converter and determining the optimal scrap steel content in the converter metal charge under insufficient heat conditions. The technical solution is a method for determining the scrap steel content in converter metal charge under insufficient heat conditions, comprising: 1) determining the amount of exothermic agent used; 2) calculating the cost of internal reheating in the converter; 3) calculating the cost of preheating scrap steel outside the converter; 4) calculating the input cost of increasing scrap steel usage in the converter; 5) calculating the benefits of increasing scrap steel usage in the converter; and 6) determining the scrap steel content in the converter metal charge. This method can determine the optimal scrap steel content in the converter metal charge under increased production conditions based on market fluctuations, thereby maximizing benefits.

Description

Technical Field

[0001] This invention relates to a technology for determining the amount of scrap steel used in converter metal materials, and particularly to a method for determining the scrap steel content in converter metal materials under insufficient heat conditions, belonging to the field of iron and steel metallurgical technology. Background Technology

[0002] The converter requires a specific heat level for the molten steel to reach the final temperature. As the scrap ratio increases, the heat level of the incoming metal decreases. When the scrap ratio exceeds the heat balance scrap ratio, the converter faces a heat shortage problem. In this case, further increasing the scrap ratio will increase the heat deficit, making it difficult to meet the final molten steel temperature requirements. Additional heat must be added to the converter through other means, such as preheating the scrap and using exothermic agents. However, these methods all require investment. Therefore, more scrap in the converter is not necessarily better. The benefits of adding scrap to the converter should be calculated based on changes in the prices of scrap, exothermic agents, hot-rolled coils, and other materials. The amount of scrap added to the converter should be dynamically adjusted to maximize profits.

[0003] Chinese patent application CN104328241A discloses a method for obtaining process efficiency in steelmaking. Based on the steelmaking material balance, energy balance, and steelmaking furnace type, it determines the smelting cycle and material consumption, and calculates the profit margin per ton of steel and process efficiency. This provides a convenient way to select a reasonable iron-containing furnace charge composition and determine the type of steelmaking furnace to be built, thereby reducing steelmaking costs. However, this technology is aimed at the profit per ton of steel produced in the conventional way and cannot assess the efficiency of preheating scrap steel and different amounts of scrap steel added under different market conditions.

[0004] Chinese patent application CN114360665A discloses a method for batching scrap steel in converter smelting. Based on the scrap steel yield, the corresponding cooling effect of the scrap steel, the waste heat temperature of the converter smelting, the type of scrap steel, the proportion of scrap steel added and its corresponding cooling effect, the total amount of scrap steel added is obtained through model equations, and the amount of different types of scrap steel added is obtained through relational functions. This batching method can reduce the number of manual calculations and save on raw material costs and energy costs. However, this technology calculates the amount of different scrap steel added under the condition of converter heat balance, and cannot evaluate the benefits of adding scrap steel under different conditions. Summary of the Invention

[0005] The purpose of this invention is to provide a method for determining the scrap steel content in converter metal charge under insufficient heat conditions. It mainly addresses the technical problems of being unable to assess the benefits of increasing scrap steel usage in the converter and determining the optimal scrap steel content in the converter metal charge when the converter's heat is insufficient. This invention primarily solves the technical problems of how to reasonably assess the economic benefits and determine the scrap steel content in the converter metal charge when increasing the amount of scrap steel and reducing the amount of molten iron in the converter while maintaining a converter heat balance, in order to increase steel production and economic efficiency. It provides decision support for determining the scrap steel content in the converter metal charge.

[0006] The converter thermal balance described in this invention refers to the state in which the converter smelting endpoint temperature reaches the target temperature range under the following conditions: cold-pressed balls or sludge balls are added to 9 kg / ton of molten steel during the converter blowing process, no iron ore or heating agent is added, and no iron blowing is performed to raise the temperature at the converter smelting endpoint.

[0007] The technical solution adopted in this invention is a method for determining the scrap steel content in converter metal charge under insufficient heat conditions, comprising the following steps:

[0008] 1) Determine the dosage of the heating agent. The heating agents include carbonaceous heating agent and heating ferrosilicon. Use the carbonaceous heating agent first, and its maximum dosage is m. max When the calculated amount of carbonaceous heating agent exceeds m max At that time, the amount of carbonaceous heating agent used was m max The remaining carbonaceous heating agents are replaced with heated ferrosilicon, m max This refers to the maximum usage mass of carbonaceous exothermic agent per ton of steel in converters, expressed in kg / ton of steel, m max The range is 15-25 kg / ton of steel. The dosage of carbonaceous exothermic agent and heating ferrosilicon is calculated according to formulas (1) and (2).

[0009] (1);

[0010] (2);

[0011] In formulas (1) to (2), m 碳 This refers to the dosage of carbonaceous exothermic agent, expressed in kg / ton of steel, m. 硅 To increase the amount of ferrosilicon used, the unit is kg / ton of steel, Δw 废,发 To increase the scrap steel content in the converter metal charge based on thermal equilibrium using an exothermic agent, k 碳 The amount of carbonaceous exothermic agent required to increase the scrap steel content in converter metal charge by 1%, expressed in kg / ton of steel, kJ / kg. 硅 The amount of ferrosilicon required to increase the scrap steel content in converter metal charge by 1%, expressed in kg / ton of steel;

[0012] 2) Calculate the internal heating cost of the converter, according to formulas (3) to (8).

[0013] (3);

[0014] (4);

[0015] (5);

[0016] (6);

[0017] (7);

[0018] (8);

[0019] In formulas (3) to (8), c1 is the cost of reheating inside the converter, in yuan / ton of steel; c2 is the cost of the heating agent itself, in yuan / ton of steel; c3 is the increased cost of auxiliary materials, in yuan / ton of steel; c4 is the increased cost of steel material consumption, in yuan / ton of steel; c5 is the increased cost of oxygen, in yuan / ton of steel; and Rb 煤 The increased revenue from converter gas is expressed in yuan per ton of steel, m 碳 This refers to the dosage of carbonaceous exothermic agent, expressed in kg / ton of steel, m. 硅 This refers to the amount of ferrosilicon used, expressed in kg / ton of steel, m. 渣 This refers to the amount of converter slag, expressed in kg / ton of steel, p 碳 The price is the unit price of the carbonaceous exothermic agent, expressed in yuan / ton, p 硅 This is the unit price of ferrosilicon, in yuan / t, p 石灰 The price is per unit of quicklime, expressed in yuan / ton. 轻白 The price per ton (t) is for lightly calcined dolomite. 钢 This is the unit price of molten steel, in yuan / t, p 氧 The price per unit of oxygen is yuan / Nm³. 3 p 煤气 This is the unit price of converter gas, in yuan / Nm³. 3 w Si The mass content of silicon in ferrosilicon, w CaO The mass content of calcium oxide in quicklime, w MgO,渣 The mass content of magnesium oxide in the final slag of the converter, w MgO The mass content of magnesium oxide in lightly calcined dolomite, w TFe The total iron content and w in the final slag of the converter when the heat is insufficient TFe,0 When the converter has excess heat, the total iron content and w in the final slag of the converter are... 挥,石灰 The mass content of volatile matter in quicklime, w 挥,轻白The mass content of volatile matter in lightly calcined dolomite, w C R represents the carbon mass content in the carbonaceous exothermic agent, R represents the binary basicity of the final residue, and α represents the carbon content in the carbonaceous exothermic agent. C For the yield of carbonaceous exothermic agent, α 煤气 β represents the converter gas recovery rate generated by the carbonaceous exothermic agent. CO β represents the mass percentage of carbon produced by oxidation to CO relative to the total carbon content. CO2 The mass content of carbon that is oxidized to produce CO2 out of the total carbon;

[0020] 3) Calculate the preheating cost of scrap steel outside the converter. The scrap steel is preheated in the scrap steel preheating zone outside the converter. The preheating cost of scrap steel outside the converter is calculated according to formulas (9) to (12).

[0021] (9);

[0022] (10);

[0023] (11);

[0024] (12);

[0025] In formulas (9) to (12), c6 is the preheating cost of scrap steel outside the converter, in yuan, p 预热 This is the price for preheated scrap steel, in yuan / ton of billet, m 坯 The mass of continuously cast billets produced in the furnace is expressed in tons (t) or cubic meters (m). 装 The total mass of the converter metal charge is expressed in tons (t) or w. 废,平 Δw represents the scrap steel content in the converter metal charge at heat equilibrium. 废 To increase the scrap steel content in the converter metal charge based on heat balance through the use of exothermic agents and preheated scrap steel, w 废,金 w represents the mass content of metals in scrap steel. 铁,金 α represents the mass content of metals in molten iron. 转 α represents the converter metal yield. 连 Δw represents the yield of continuously cast metal. 废,发 Based on thermal equilibrium, the scrap steel content in the converter metal charge is increased by using an exothermic agent, Δm 废,预 The increase in scrap steel mass per heat by preheating the scrap steel converter on the basis of heat balance, expressed in tons (t), ΔT. 预 The contribution of scrap steel preheating to the temperature of molten steel in the converter, expressed in °C, ΔT 废 The temperature drop of molten steel in scrap steel is expressed in °C per ton of scrap steel.

[0026] 4) Calculate the input cost of incremental scrap steel for the converter, using formulas (13) to (14).

[0027] (13);

[0028] (14);

[0029] In formulas (13) to (14), c7 is the input cost of incremental scrap steel in the converter, in yuan / ton of scrap steel, c1 is the reheating cost in the converter, in yuan / ton of steel, and m 坯 The mass of continuously cast billets produced in the furnace, in tons (t), α 连 Δm represents the yield of continuously cast metal. 废,发 The increase in scrap steel mass per heat due to in-converter reheating is expressed in tons (t) and Δm. 废,预 The increase in scrap mass per heat due to external preheating of scrap steel in the converter, expressed in tons (t) or cubic meters (m). 碳 This refers to the dosage of carbonaceous exothermic agent, expressed in kg / ton of steel, m. 硅 This refers to the amount of ferrosilicon used, expressed in kg / ton of steel, k. 碳 The amount of carbonaceous exothermic agent required to increase the scrap steel content in converter metal charge by 1%, in kg / ton of steel, kJ / kg. 硅 To increase the mass of scrap steel by 1% compared to ferrosilicon, the unit is kg / ton of steel;

[0030] 5) Calculate the incremental scrap steel benefit of the converter, according to formulas (15) to (17).

[0031] (15);

[0032] (16);

[0033] (17);

[0034] In formulas (15) to (17), Eb represents the benefit of incremental scrap steel production in the converter based on heat balance, expressed in yuan (m). 坯,0 To increase the continuous casting output of the converter by 1 ton of scrap steel, the unit is t / ton of scrap steel, m 热,0 To increase the hot-rolled output of the converter by 1 ton of scrap steel, the unit is t / ton of scrap steel, w 废,金 α represents the mass content of metals in scrap steel. 转 For converter metal recovery, α 连 For continuous casting metal yield, α 热 p represents the hot-rolled yield. 热轧 This represents the average price of hot-rolled coils, in yuan / t. 废 C7 represents the average price of scrap steel, in yuan / ton; C8 represents the input cost of incremental scrap steel for converters, in yuan / ton of scrap steel; C9 represents the variable cost of steelmaking excluding metal materials, in yuan / ton of steel; C9 represents the variable cost of hot rolling, in yuan / ton; Rb 回收The price for recycling solid waste metals generated from the continuous casting and hot rolling processes in steelmaking is expressed in yuan / ton of steel, Δm. 废,发 The increase in scrap steel mass per heat due to in-converter reheating is expressed in tons (t) and Δm. 废,预 The increase in scrap steel mass per heat due to external preheating of scrap steel in the converter, expressed in tons;

[0035] 6) Determine the scrap steel content w in the converter metal charge. 废 In step 1), gradually increase Δw 废,发 The assignment step size is s, where 0 < s ≤ 2%. Repeat steps 1) to 5) to calculate the incremental scrap steel benefit Eb of the converter. The optimal increment of scrap steel content in the converter metal charge is the increment of scrap steel content in the converter metal charge corresponding to the maximum incremental scrap steel benefit. At this time, w 废 =w 废,平 +Δw 废 .

[0036] The selection criteria for process parameters in this invention are as follows:

[0037] 1. Determining the dosage of the heating agent

[0038] In step 1), the unit price of carbonaceous exothermic agent is relatively low, and the cost of using it for temperature raising is low. However, its usage should not be too high. On the one hand, the sulfur content in carbonaceous exothermic agent is relatively high, and adding too much will cause a significant increase in the sulfur content in the molten steel, exceeding the steel grade standard requirements. On the other hand, carbonaceous exothermic agent has a low density, and after being added to the converter, it is largely encased in the slag, reacting with FeO in the slag to produce CO and CO2 gases. Adding too much will cause severe slag foaming and continuous splashing. Through extensive research, it has been found that when the maximum usage weight of carbonaceous exothermic agent per ton of steel in the converter is controlled at 20-30 kg, the advantage of its low price can be fully utilized, while its negative impact on production is controlled to an acceptable level.

[0039] 2. Determination of the cost of internal heat replenishment in the converter

[0040] In step 2), the cost per ton of steel using exothermic agents includes not only the agent's own cost but also the costs of auxiliary materials, steel consumption, and oxygen. Simultaneously, there is the benefit of converter gas recovery. This is because when insufficient heat is used with ferrosilicon, the SiO2 in the converter slag increases. To maintain slag basicity and MgO content, lime and lightly calcined dolomite must be added, thus increasing the amount of auxiliary materials and converter slag. The slag contains a higher TFe content, and increased slag volume means increased converter blowdown losses. Furthermore, due to insufficient heat, the TFe content in the slag is also higher than when heat is abundant, leading to increased steel consumption. All exothermic agents require oxygen to undergo chemical reactions that release heat. The oxidation product of carbonaceous exothermic agents is mainly CO, which can increase converter gas recovery.

[0041] 3. The value of metal recovery from solid waste is included in the calculation of the incremental scrap steel benefit from converters.

[0042] Step 5) considers the metal recycling value in solid waste because the metals lost during the production process of converter, continuous casting and hot rolling can be recycled as converter metal materials after relevant treatment, thereby generating economic benefits. Solid waste includes converter slag, continuous casting ladle surplus steel, continuous casting intermediate ladle surplus steel, slab head and tail cuts, hot rolling surplus, and hot rolling iron oxide scale.

[0043] Compared with the prior art, the present invention has the following positive effects: 1. The method of the present invention directly reflects the effect of using exothermic agents and preheating scrap steel as increasing the amount of scrap steel used in converters, thereby increasing the output of hot-rolled coils. The input cost of increasing the amount of scrap steel includes the cost of preheating scrap steel and the cost of exothermic agents, auxiliary materials, oxygen, steel consumption, and gas recovery revenue. The benefit of increasing the amount of scrap steel is the benefit brought by the increase in the output of hot-rolled coils. The benefit of increasing the amount of scrap steel is reflected in the price difference between hot-rolled and scrap steel after deducting the processing costs of each process and the input cost of increasing scrap steel. At the same time, the metal recovery value lost in each process is also considered. The present invention has clear logic, comprehensively considers influencing factors, and the calculation results are consistent with the actual production. 2. The method of this invention can intuitively show the trend of the increase in scrap steel per ton of efficiency under insufficient heat conditions, i.e., under the condition of maximizing the amount of scrap steel used in the converter, by using exothermic agents or preheating scrap steel, as the scrap steel mass content in the converter metal charge increases. Based on market changes such as scrap steel price, hot-rolled coil price, and exothermic agent price, the optimal increase in scrap steel mass content in the converter metal charge can be determined on the basis of converter heat balance, thereby helping to maximize efficiency. Detailed Implementation

[0044] The present invention will be further described below with reference to specific embodiments 1 to 3, as shown in Tables 1 to 7.

[0045] This invention takes a 250t top-and-bottom blown converter as an example. The average addition amount of cold-pressed briquettes is 9 kg / ton of molten steel, Δw 废,发 The assignment step size is 1%.

[0046] A method for determining the scrap steel content in converter metal charge under insufficient heat conditions, comprising the following steps:

[0047] 1) Determine the dosage of the heating agent. The heating agents include carbonaceous heating agent and heating ferrosilicon. Use the carbonaceous heating agent first, and its maximum dosage is m. max When the calculated amount of carbonaceous heating agent exceeds m max At that time, the amount of carbonaceous heating agent used was m max The remaining carbonaceous heating agents are replaced with heated ferrosilicon, m max This refers to the maximum usage mass of carbonaceous exothermic agent per ton of steel in converters, expressed in kg / ton of steel, mmax The range is 15-25 kg / ton of steel. The dosage of carbonaceous exothermic agent and heating ferrosilicon is calculated according to formulas (1) and (2).

[0048] (1);

[0049] (2);

[0050] In formulas (1) to (2), m 碳 This refers to the dosage of carbonaceous exothermic agent, expressed in kg / ton of steel, m. 硅 To increase the amount of ferrosilicon used, the unit is kg / ton of steel, Δw 废,发 To increase the scrap steel content in the converter metal charge based on thermal equilibrium using an exothermic agent, k 碳 The amount of carbonaceous exothermic agent required to increase the scrap steel content in converter metal charge by 1%, expressed in kg / ton of steel, kJ / kg. 硅 The amount of ferrosilicon required to increase the scrap steel content in converter metal charge by 1%, expressed in kg / ton of steel;

[0051] 2) Calculate the internal heating cost of the converter, according to formulas (3) to (8).

[0052] (3);

[0053] (4);

[0054] (5);

[0055] (6);

[0056] (7);

[0057] (8);

[0058] In formulas (3) to (8), c1 is the cost of reheating inside the converter, in yuan / ton of steel; c2 is the cost of the heating agent itself, in yuan / ton of steel; c3 is the increased cost of auxiliary materials, in yuan / ton of steel; c4 is the increased cost of steel material consumption, in yuan / ton of steel; c5 is the increased cost of oxygen, in yuan / ton of steel; and Rb 煤 The increased revenue from converter gas is expressed in yuan per ton of steel, m 碳 This refers to the dosage of carbonaceous exothermic agent, expressed in kg / ton of steel, m. 硅 This refers to the amount of ferrosilicon used, expressed in kg / ton of steel, m. 渣 This refers to the amount of converter slag, expressed in kg / ton of steel, p 碳 The price is the unit price of the carbonaceous exothermic agent, expressed in yuan / ton, p硅 This is the unit price of ferrosilicon, in yuan / t, p 石灰 The price is per unit of quicklime, expressed in yuan / ton. 轻白 The price per ton (t) is for lightly calcined dolomite. 钢 This is the unit price of molten steel, in yuan / t, p 氧 The price per unit of oxygen is yuan / Nm³. 3 p 煤气 This is the unit price of converter gas, in yuan / Nm³. 3 w Si The mass content of silicon in ferrosilicon, w CaO The mass content of calcium oxide in quicklime, w MgO,渣 The mass content of magnesium oxide in the final slag of the converter, w MgO The mass content of magnesium oxide in lightly calcined dolomite, w TFe The total iron content and w in the final slag of the converter when the heat is insufficient TFe,0 When the converter has excess heat, the total iron content and w in the final slag of the converter are... 挥,石灰 The mass content of volatile matter in quicklime, w 挥,轻白 The mass content of volatile matter in lightly calcined dolomite, w C R represents the carbon mass content in the carbonaceous exothermic agent, R represents the binary basicity of the final residue, and α represents the carbon content in the carbonaceous exothermic agent. C For the yield of carbonaceous exothermic agent, α 煤气 β represents the converter gas recovery rate generated by the carbonaceous exothermic agent. CO β represents the mass percentage of carbon produced by oxidation to CO relative to the total carbon content. CO2 The mass content of carbon that is oxidized to produce CO2 out of the total carbon;

[0059] The cost of preheating scrap outside the converter is calculated by preheating the scrap in the preheating zone outside the converter. The cost of preheating scrap outside the converter is calculated according to formulas (9) to (12).

[0060] (9);

[0061] (10);

[0062] (11);

[0063] (12);

[0064] In formulas (9) to (12), c6 is the preheating cost of scrap steel outside the converter, in yuan, p 预热 This is the price for preheated scrap steel, in yuan / ton of billet, m 坯 The mass of continuously cast billets produced in the furnace is expressed in tons (t) or cubic meters (m). 装 The total mass of the converter metal charge is expressed in tons (t) or w. 废,平Δw represents the scrap steel content in the converter metal charge at heat equilibrium. 废 To increase the scrap steel content in the converter metal charge based on heat balance through the use of exothermic agents and preheated scrap steel, w 废,金 w represents the mass content of metals in scrap steel. 铁,金 α represents the mass content of metals in molten iron. 转 α represents the converter metal yield. 连 Δw represents the yield of continuously cast metal. 废,发 Based on thermal equilibrium, the scrap steel content in the converter metal charge is increased by using an exothermic agent, Δm 废,预 The increase in scrap steel mass per heat by preheating the scrap steel converter on the basis of heat balance, expressed in tons (t), ΔT. 预 The contribution of scrap steel preheating to the temperature of molten steel in the converter, expressed in °C, ΔT 废 The temperature drop of molten steel in scrap steel is expressed in °C per ton of scrap steel.

[0065] 4) Calculate the input cost of incremental scrap steel for the converter, using formulas (13) to (14).

[0066] (13);

[0067] (14);

[0068] In formulas (13) to (14), c7 is the input cost of incremental scrap steel in the converter, in yuan / ton of scrap steel, c1 is the reheating cost in the converter, in yuan / ton of steel, and m 坯 The mass of continuously cast billets produced in the furnace, in tons (t), α 连 Δm represents the yield of continuously cast metal. 废,发 The increase in scrap steel mass per heat due to in-converter reheating is expressed in tons (t) and Δm. 废,预 The increase in scrap mass per heat due to external preheating of scrap steel in the converter, expressed in tons (t) or cubic meters (m). 碳 This refers to the dosage of carbonaceous exothermic agent, expressed in kg / ton of steel, m. 硅 This refers to the amount of ferrosilicon used, expressed in kg / ton of steel, k. 碳 The amount of carbonaceous exothermic agent required to increase the scrap steel content in converter metal charge by 1%, in kg / ton of steel, kJ / kg. 硅 To increase the mass of scrap steel by 1% compared to ferrosilicon, the unit is kg / ton of steel;

[0069] 5) Calculate the incremental scrap steel benefit of the converter, according to formulas (15) to (17).

[0070] (15);

[0071] (16);

[0072] (17);

[0073] In formulas (15) to (17), Eb represents the benefit of incremental scrap steel production in the converter based on heat balance, expressed in yuan (m). 坯,0 To increase the continuous casting output of the converter by 1 ton of scrap steel, the unit is t / ton of scrap steel, m 热,0 To increase the hot-rolled output of the converter by 1 ton of scrap steel, the unit is t / ton of scrap steel, w 废,金 α represents the mass content of metals in scrap steel. 转 For converter metal recovery, α 连 For continuous casting metal yield, α 热 p represents the hot-rolled yield. 热轧 This represents the average price of hot-rolled coils, in yuan / t. 废 C7 represents the average price of scrap steel, in yuan / ton; C8 represents the input cost of incremental scrap steel for converters, in yuan / ton of scrap steel; C9 represents the variable cost of steelmaking excluding metal materials, in yuan / ton of steel; C9 represents the variable cost of hot rolling, in yuan / ton; Rb 回收 The price for recycling solid waste metals generated from the continuous casting and hot rolling processes in steelmaking is expressed in yuan / ton of steel, Δm. 废,发 The increase in scrap steel mass per heat due to in-converter reheating is expressed in tons (t) and Δm. 废,预 The increase in scrap steel mass per heat due to external preheating of scrap steel in the converter, expressed in tons;

[0074] 6) Determine the scrap steel content w in the converter metal charge. 废 In step 1), gradually increase Δw 废,发 The assignment step is 1%, and steps 1) to 5) are repeated to calculate the incremental scrap steel benefit Eb of the converter. The optimal increment of scrap steel content in the converter metal charge is the increment of scrap steel content in the converter metal charge corresponding to the maximum incremental scrap steel benefit. At this time, w 废 =w 废,平 +Δw 废 .

[0075] Table 1 Material composition parameters (by weight percentage) of embodiments of the present invention.

[0076]

[0077] Table 2 Converter smelting process parameters of the present invention (I)

[0078]

[0079] Table 3. Converter smelting process parameters (II) of this invention embodiment

[0080]

[0081] Table 4 Price parameters of embodiments of the present invention (I)

[0082]

[0083] Table 5 Price parameters of embodiments of the present invention (II)

[0084]

[0085] Table 6 Process Costs and Yield Parameters of Embodiments of the Invention

[0086]

[0087] Table 7. Incremental Scrap Steel Benefits of Converter in Embodiments of the Invention

[0088]

[0089] As shown in Tables 1-7, the material composition parameters, converter smelting process parameters, price parameters, process cost and yield parameters, and converter incremental scrap steel benefits of Examples 1-3 are presented. Compared with Example 1, Example 2 improved the preheating temperature of preheated scrap steel outside the converter and reduced the heat loss of preheated scrap steel. Compared with Example 1, the temperature contribution of preheated scrap steel to molten steel in the converter increased from 12℃ / ton of scrap steel to 14℃ / ton of scrap steel, and the price of preheated scrap steel increased from 2.1 yuan / ton of billet to 2.5 yuan / ton of billet. The converter incremental scrap steel benefit increased by 107.5 yuan. Compared with Example 2, the price of hot-rolled coil in Example 3 decreased from 4863 yuan / ton of hot-rolled coil to 4686 yuan / ton of hot-rolled coil. The price difference between hot-rolled coil and scrap steel was 1325 yuan / ton. At this time, the converter incremental scrap steel benefit obtained by preheating scrap steel outside the converter was 479 yuan / ton of scrap steel. The benefit of increasing the amount of scrap steel used in the converter by supplementing heat inside the converter was negative. According to Table 7, in Examples 1-3, the incremental scrap steel benefits of converters generally show a trend of first increasing and then decreasing. The optimal scrap steel content in the converter metal charge is 24.77%, 24.77%, and 18.77%, respectively, which corresponds to the greatest incremental scrap steel benefits of converters.

[0090] This invention can clearly show how the incremental scrap steel benefit of a converter changes with the increase in the scrap steel mass content in the metal charge. By determining the location of the highest point of incremental scrap steel benefit in the converter, the optimal scrap steel mass content in the converter metal charge can be determined, thereby maximizing the benefit.

[0091] In addition to the embodiments described above, the present invention may have other implementations. All technical solutions formed by equivalent substitution or equivalent transformation fall within the protection scope claimed by the present invention.

Claims

1. A method for determining the scrap steel content in converter metal charge under insufficient heat conditions, characterized in that, The method includes the following steps: 1) Determine the dosage of the heating agent. The heating agents include carbonaceous heating agent and heating ferrosilicon. Use the carbonaceous heating agent first, and its maximum dosage is m. max When the calculated amount of carbonaceous heating agent exceeds m max At that time, the amount of carbonaceous heating agent used was m max The remaining carbonaceous heating agents are replaced with heated ferrosilicon, m max This refers to the maximum usage mass of carbonaceous exothermic agent per ton of steel in converters, expressed in kg / ton of steel, m max The range is 15-25 kg / ton of steel. The dosage of carbonaceous exothermic agent and heating ferrosilicon is calculated according to formulas (1) and (2). （1）； （2）； In formulas (1) to (2), m 碳 This refers to the dosage of carbonaceous exothermic agent, expressed in kg / ton of steel, m. 硅 To increase the amount of ferrosilicon used, the unit is kg / ton of steel, Δw 废,发 To increase the scrap steel content in the converter metal charge based on thermal equilibrium using an exothermic agent, k 碳 The amount of carbonaceous exothermic agent required to increase the scrap steel content in converter metal charge by 1%, expressed in kg / ton of steel, kJ / kg. 硅 The amount of ferrosilicon required to increase the scrap steel content in converter metal charge by 1%, expressed in kg / ton of steel; 2) Calculate the internal heating cost of the converter, according to formulas (3) to (8). （3）； （4）； （5）； （6）； （7）； （8）； In formulas (3) to (8), c1 is the cost of reheating inside the converter, in yuan / ton of steel; c2 is the cost of the heating agent itself, in yuan / ton of steel; c3 is the increased cost of auxiliary materials, in yuan / ton of steel; c4 is the increased cost of steel material consumption, in yuan / ton of steel; c5 is the increased cost of oxygen, in yuan / ton of steel; and Rb 煤 The increased revenue from converter gas is expressed in yuan per ton of steel, m 碳 This refers to the dosage of carbonaceous exothermic agent, expressed in kg / ton of steel, m. 硅 This refers to the amount of ferrosilicon used, expressed in kg / ton of steel, m. 渣 This refers to the amount of converter slag, expressed in kg / ton of steel, p 碳 The price is the unit price of the carbonaceous exothermic agent, expressed in yuan / ton, p 硅 This is the unit price of ferrosilicon, in yuan / t, p 石灰 The price is per unit of quicklime, expressed in yuan / ton. 轻白 The price per ton (t) is for lightly calcined dolomite. 钢 This is the unit price of molten steel, in yuan / t, p 氧 The price per unit of oxygen is yuan / Nm³. 3 p 煤气 This is the unit price of converter gas, in yuan / Nm³. 3 w Si The mass content of silicon in ferrosilicon, w CaO The mass content of calcium oxide in quicklime, w MgO,渣 The mass content of magnesium oxide in the final slag of the converter, w MgO The mass content of magnesium oxide in lightly calcined dolomite, w TFe The total iron content and w in the final slag of the converter when the heat is insufficient TFe,0 When the converter has excess heat, the total iron content and w in the final slag of the converter are... 挥,石灰 The mass content of volatile matter in quicklime, w 挥,轻白 The mass content of volatile matter in lightly calcined dolomite, w C R represents the carbon mass content in the carbonaceous exothermic agent, R represents the binary basicity of the final residue, and α represents the carbon content in the carbonaceous exothermic agent. C For the yield of carbonaceous exothermic agent, α 煤气 β represents the converter gas recovery rate generated by the carbonaceous exothermic agent. CO β represents the mass percentage of carbon produced by oxidation to CO relative to the total carbon content. CO2 The mass content of carbon that is oxidized to produce CO2 out of the total carbon; 3) Calculate the preheating cost of scrap steel outside the converter. The scrap steel is preheated in the scrap steel preheating zone outside the converter. The preheating cost of scrap steel outside the converter is calculated according to formulas (9) to (12). （9）； （10）； （11）； （12）； In formulas (9) to (12), c6 is the preheating cost of scrap steel outside the converter, in yuan, p 预热 This is the price for preheated scrap steel, in yuan / ton of billet, m 坯 The mass of continuously cast billets produced in the furnace is expressed in tons (t) or cubic meters (m). 装 The total mass of the converter metal charge is expressed in tons (t) or w. 废,平 Δw represents the scrap steel content in the converter metal charge at heat equilibrium. 废 To increase the scrap steel content in the converter metal charge based on heat balance through the use of exothermic agents and preheated scrap steel, w 废,金 w represents the mass content of metals in scrap steel. 铁,金 α represents the mass content of metals in molten iron. 转 α represents the converter metal yield. 连 Δw represents the yield of continuously cast metal. 废,发 Based on thermal equilibrium, the scrap steel content in the converter metal charge is increased by using an exothermic agent, Δm 废,预 The increase in scrap steel mass per heat by preheating the scrap steel converter on the basis of heat balance, expressed in tons (t), ΔT. 预 The contribution of scrap steel preheating to the temperature of molten steel in the converter, expressed in °C, ΔT 废 The temperature drop of molten steel in scrap steel is expressed in °C per ton of scrap steel. 4) Calculate the input cost of incremental scrap steel for the converter, using formulas (13) to (14). （13）； （14）； In formulas (13) to (14), c7 is the input cost of incremental scrap steel in the converter, in yuan / ton of scrap steel, c1 is the reheating cost in the converter, in yuan / ton of steel, and m 坯 The mass of continuously cast billets produced in the furnace, in tons (t), α 连 Δm represents the yield of continuously cast metal. 废,发 The increase in scrap steel mass per heat due to in-converter reheating is expressed in tons (t) and Δm. 废,预 The increase in scrap mass per heat due to external preheating of scrap steel in the converter, expressed in tons (t) or cubic meters (m). 碳 This refers to the dosage of carbonaceous exothermic agent, expressed in kg / ton of steel, m. 硅 This refers to the amount of ferrosilicon used, expressed in kg / ton of steel, k. 碳 The amount of carbonaceous exothermic agent required to increase the scrap steel content in converter metal charge by 1%, in kg / ton of steel, kJ / kg. 硅 To increase the mass of scrap steel by 1% compared to ferrosilicon, the unit is kg / ton of steel; 5) Calculate the incremental scrap steel benefit of the converter, according to formulas (15) to (17). （15）； （16）； （17）； In formulas (15) to (17), Eb represents the benefit of incremental scrap steel production in the converter based on heat balance, expressed in yuan (m). 坯,0 To increase the continuous casting output of the converter by 1 ton of scrap steel, the unit is t / ton of scrap steel, m 热,0 To increase the hot-rolled output of the converter by 1 ton of scrap steel, the unit is t / ton of scrap steel, w 废,金 α represents the mass content of metals in scrap steel. 转 For converter metal recovery, α 连 For continuous casting metal yield, α 热 p represents the hot-rolled yield. 热轧 This represents the average price of hot-rolled coils, in yuan / t. 废 C7 represents the average price of scrap steel, in yuan / ton; C8 represents the input cost of incremental scrap steel for converters, in yuan / ton of scrap steel; C9 represents the variable cost of steelmaking excluding metal materials, in yuan / ton of steel; C9 represents the variable cost of hot rolling, in yuan / ton; Rb 回收 The price for recycling solid waste metals generated from the continuous casting and hot rolling processes in steelmaking is expressed in yuan / ton of steel, Δm. 废,发 The increase in scrap steel mass per heat due to in-converter reheating is expressed in tons (t) and Δm. 废,预 The increase in scrap steel mass per heat due to external preheating of scrap steel in the converter, expressed in tons; 6) Determine the scrap steel content w in the converter metal charge. 废 In step 1), gradually increase Δw 废,发 The assignment step size is s, where 0 < s ≤ 2%. Repeat steps 1) to 5) to calculate the incremental scrap steel benefit Eb of the converter. The optimal increment of scrap steel content in the converter metal charge is the increment of scrap steel content in the converter metal charge corresponding to the maximum incremental scrap steel benefit. At this time, w 废 =w 废,平 +Δw 废 .

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