High-proportion in-furnace smelting method for raw iron ore in wide softening and melting zone

Abstract

The invention provides a high-proportion in-furnace smelting method for raw iron ore in a wide soft melting zone. The in-furnace smelting method comprises a material preparation optimization method before raw lump ore enters a furnace, a raw lump ore batch weight design method, an airflow index control method, a furnace temperature control method, a slag system management method and an out-of-furnace iron outlet management method. According to the method, almost all adverse effects after the raw lump ores with the soft melting temperature of 1100-1500 DEG C in the wide soft melting zone enter the furnace are reduced to the minimum, the industrial problem of smelting the raw lump ores in the wide soft melting zone in the furnace is fundamentally solved, the blast furnace smelting cost is reduced, and the method is suitable for large-scale popularization and application.

Description

Technical Field

[0001] The present invention relates to the technical field of steel smelting, and in particular to a method for smelting pig iron ore with a wide softening range and a high proportion of pig iron ore into a furnace. Background Art

[0002] When iron ore is heated and reduced, it produces a large amount of FeO, which readily reacts with gangue minerals such as SiO₂, CaO, and Al₂O₃ in the ore to form a low-melting-point liquid phase. As the temperature rises, the amount of liquid increases. Once the ore reaches a certain temperature, it begins to deform, shrink, and soften under load. Continued temperature increases cause further softening and shrinkage until the molten metal drips. During the blast furnace ironmaking process, molten metal drips from the beginning of softening, forming a soft melting zone within the furnace. The poor permeability of this zone restricts reduction and heat transfer. Therefore, the soft melting zone should be thin and positioned low. The thickness and position of the soft melting zone are directly related to the ore's softening properties and droplet properties within the blast furnace. Ore with a high softening temperature and a narrow softening temperature range results in a thin, low-lying soft melting zone within the blast furnace, resulting in improved permeability. Therefore, the ore's load reduction softening property is one of the key indicators for evaluating the high-temperature metallurgical performance of iron ore, and different ores have different load reduction softening properties.

[0003] Most domestic studies have shown that raw ore contains large amounts of crystalline water and carbonates, making it susceptible to thermal explosion. When the proportion of raw ore used in some domestic blast furnaces increases, gas utilization generally decreases by 1% to 2%, while the coke ratio increases by approximately 10kg. The softening temperature of raw ore is generally lower than that of artificially enriched ores. Extensive experimental data indicates that the softening temperature of most raw ore is around 1000°C, with some around 900°C. Due to the low softening temperature of raw ore, upon entry into the blast furnace, the soft melting zone within the blast furnace shifts upward or adheres to the furnace walls, causing malfunctions. This deteriorates the permeability of the charge column, increases the pressure differential within the furnace, and hinders charge unloading. This creates adverse effects on intensified smelting in the blast furnace and increases the difficulty of furnace operation.

[0004] The steel industry faces a challenging situation. Driven by cost pressures, various manufacturers are gradually transitioning from "fine material smelting" to "economic charge smelting." Compared to mainstream high-quality iron ore, various economic ores (discounted ores) offer significant price advantages. However, due to their low initial melting temperature and high final melting temperature upon smelting in the blast furnace, these ores exhibit a wide soft melting zone, impairing blast furnace permeability, and affecting airflow distribution above the furnace, ultimately impacting the furnace's longevity. This presents a technical challenge for steelmakers.

[0005] CN106399608A discloses a method for improving the efficiency of blast furnace smelting high-aluminum iron ore using highly reactive coke. By using highly reactive coke instead of ordinary metallurgical coke to make coke pieces and charging them into the blast furnace, the excellent reactivity of the highly reactive coke pieces can reduce the temperature of the heat reserve area, increase the pre-reduction degree of the iron-containing charge, reduce the FeO content in the primary slag phase containing Al2O3, increase the melting point of the primary slag phase containing Al2O3, narrow the melting range, and shift the soft melting zone downward. This further improves the permeability of the material layer on the basis of mixed ore and coke charging, thereby achieving the purpose of improving the efficiency of blast furnace smelting high-aluminum iron ore. This process helps to utilize low-quality iron ore and low-quality coke resources, reduce the ironmaking production costs of steel enterprises, and ensure ironmaking production efficiency.

[0006] CN117126971A discloses a method for operating a blast furnace with high-proportion raw ore, comprising the following steps: S1, selecting and screening the raw ore, sintered ore, pellet ore and coke according to their particle sizes; S2, presetting the blast furnace charging position and charging angle, wherein the ore position is N, the ore charging angle includes a minimum ore charging angle and a maximum ore charging angle; the coke position is N+2, the coke charging angle includes a minimum coke charging angle and a maximum coke charging angle, wherein the minimum coke charging angle is smaller than the minimum ore charging angle, and the maximum coke charging angle is larger than the maximum ore charging angle; S3, charging the ore and coke in the blast furnace in sequence according to the blast furnace charging position and charging angle.

[0007] CN105018661A discloses a method for determining the proportion of pellets and lump ores for blast furnace charging. The prepared pellets and various lump ores for blast furnace charging are made into samples, which are then placed in an inner graphite crucible. The bottom and upper layers are each covered with coke blocks. The graphite crucible containing the samples and coke blocks is then placed in an iron ore soft melting drip test device for measurement. Before adjusting the "appropriate proportion" of "high-basicity sintered ore and acidic pellets", the "appropriate proportion" of "pellets and a small amount of natural lump ores" is first optimized. This method can achieve the complementary advantages of the "high-basicity sintered ore + acidic charge" in metallurgical performance, so that blast furnace production can obtain the best operating indicators. In addition, when there is a lack of pellet clinker in the acidic charge, an appropriate proportion of high-grade lump ores can be added, making it possible to reduce blast furnace smelting costs and increase blast furnace output.

[0008] However, the above methods do not effectively solve the problems of poor permeability of blast furnace charge column, obstruction of blast furnace discharge and difficult operation in the furnace when smelting pig iron ore in a wide soft melting range. Summary of the Invention

[0009] In order to solve the above technical problems, the present invention provides a method for smelting a high proportion of pig iron ore in a wide soft melting zone into a furnace, which performs targeted optimization control from material preparation before entering the furnace to slag and iron tapping, fundamentally solving various problems of smelting pig iron ore in a wide soft melting zone into the furnace, allowing the blast furnace to run smoothly without interference and reducing the blast furnace smelting cost.

[0010] To achieve this object, the present invention adopts the following technical solutions:

[0011] The present invention provides a method for smelting pig iron ore with a high proportion in a wide soft melting range, the method comprising a material preparation optimization method before the green ore is put into the furnace, a green ore batch redesign method, a method for controlling the airflow index, a furnace temperature control method, a slag system management method, and a method for managing the pig iron out of the furnace;

[0012] The remelting temperature of the pig iron ore in the wide remelting range is 1100-1500° C.; the proportion of the pig iron ore in the wide remelting range charged into the furnace is 5%-10%.

[0013] The method for smelting pig iron ore with a high proportion in a wide soft melting range described in the present invention has been comprehensively optimized and designed from six aspects: material system optimization before the wide soft melting range pig iron ore is fed into the furnace, ore batch weight design, airflow model, furnace temperature control, slag system management and out-of-furnace pig iron management. Almost all adverse effects of the pig iron ore in the wide soft melting range with a soft melting temperature of 1100-1500°C being fed into the furnace are reduced to a minimum, fundamentally solving the industry problem of smelting pig iron ore in the wide soft melting range into the furnace, so that the blast furnace can run smoothly without interference and fuel consumption will not increase significantly. The proportion of pig iron ore in the wide soft melting range can be stably increased to 5%-10%, which can give full play to the ore matching advantage of the relatively low-priced pig iron ore in the wide soft melting range used in the blast furnace, thereby reducing the smelting cost of the blast furnace.

[0014] The material system optimization method of the green ore before entering the furnace described in the present invention distributes the green ore in the wide soft melting range in the middle annular zone of the material system after entering the furnace, thereby minimizing the impact of the use of these wide green ore on the blast furnace air flow and not causing air flow fluctuations caused by a significant increase in the blast furnace heat load.

[0015] The green ore batch redesign method of the present invention can effectively control the furnace top temperature to maintain it within a relatively reasonable range, greatly reduce the risk of harmful alkali metals circulating and enriching in the furnace top area, and stabilize the blast furnace heat load.

[0016] The method for controlling the airflow index of the present invention develops a central airflow distribution system while appropriately loosening the edge airflow, which can improve the stability of the airflow inside the blast furnace during the use of green ore in a wide soft melting range.

[0017] The furnace temperature control method of the present invention mainly controls physical heat and supplements it with silicon content control in molten iron. The lower limit of the physical heat of molten iron is strictly controlled, so that the physical heat value of molten iron is always in a reasonable range higher than the melting temperature of slag, thereby reducing the risk of deterioration of blast furnace condition.

[0018] The slag system management method of the present invention reasonably controls the magnesium-aluminum ratio of the slag and the mass content of Al2O3, so that the slag has good stability and the blast furnace has strong anti-fluctuation ability, which facilitates blast furnace operators to make targeted adjustments.

[0019] The iron-outlet management method of the present invention shortens the iron-outlet interval, cleans the slag and iron in the furnace in time, and prevents the slag and iron from being trapped and causing air flow disturbance inside the blast furnace.

[0020] The remelting temperature of the wide remelting range pig iron ore of the present invention is 1100-1500° C., for example, it can be 1100-1300° C., 1100-1400° C., 1200-1400° C., 1300-1450° C., 1300-1500° C., etc., but is not limited to the listed interval values, and other unlisted numerical intervals within the numerical range are also applicable;

[0021] The proportion of pig iron ore charged into the furnace within the wide soft melting range is 5% to 10%, for example, it can be 5%, 5.5%, 6%, 7%, 8%, 9% or 10%, etc., but is not limited to the listed values. Other values ​​not listed within this numerical range are also applicable.

[0022] Preferably, the method for optimizing the material system before the green ore is fed into the furnace comprises distributing the green ore in the wide soft melting range into the middle annular zone of the material system after feeding the green ore into the furnace.

[0023] The use of annular charging for blast furnace smelting is common knowledge in the art. This invention minimizes the impact of using green ore within a wide remelting range on the blast furnace airflow by distributing it across the central annular band of the charging system, rather than distributing it to the first (outermost) and last (innermost) bands of the existing charging system. This prevents airflow fluctuations caused by a significant increase in the blast furnace's heat load.

[0024] Preferably, the green ore batch weight design method includes adopting a small batch fast running method to replace the large batch smelting, and the small batch weight × the number of hourly batches ≥ the large batch weight × the number of hourly batches.

[0025] Preferably, the airflow index control method includes controlling the edge airflow index W to be 0.65 to 0.95, for example, it can be 0.65, 0.68, 0.7, 0.8, 0.9 or 0.95, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable; wherein, the edge airflow index W is the ratio of the sum of the temperature values ​​of the four edges of the cross temperature measuring gun in the furnace to the average temperature of the four points of the furnace top riser.

[0026] Preferably, the method for controlling the airflow index also includes controlling the central airflow index Z to be 6 to 8, for example, it can be 6, 6.5, 7, 7.5, 7.7 or 8, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable; wherein, the central airflow index Z is the ratio of the sum of the temperature values ​​of the four centers of the cross temperature measuring gun in the furnace to the average temperature of the four points of the furnace top riser.

[0027] Preferably, the furnace temperature control method includes raising the lower limit of the physical heat control of the molten iron by 5 to 10°C, for example, it can be 5°C, 5.5°C, 6°C, 7°C, 8°C or 10°C, etc., but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0028] Preferably, the temperature range of the molten iron physical heat control is related to the furnace capacity of the pig iron ore smelting blast furnace; wherein, 1000m 3 The physical heat control temperature range of molten iron in the blast furnace is 1470-1510℃, for example, it can be 1470℃, 1480℃, 1490℃, 1495℃, 1500℃ or 1510℃, but it is not limited to the listed values. Other values ​​not listed in the numerical range are also applicable; 2000m 3 The physical heat control temperature range of molten iron in the blast furnace is 1505-1535℃, for example, it can be 1505℃, 1510℃, 1520℃, 1525℃, 1530℃ or 1535℃, but it is not limited to the listed values. Other values ​​not listed in the range are also applicable; 3000m 3 The physical heat control temperature range of molten iron in blast furnaces of grade 1 and above is 1510-1540℃, for example, it can be 1510℃, 1520℃, 1525℃, 1530℃, 1535℃ or 1540℃, etc., but it is not limited to the listed values. Other values ​​not listed in this numerical range are also applicable.

[0029] The temperature range of the molten iron physical heat control of the present invention is related to the furnace capacity of the pig iron ore smelting blast furnace; wherein, 1000m 3The normal range of physical heat control temperature of molten iron in grade blast furnace is usually 1470~1510℃. When smelting green ore with wide melting range, the physical heat control temperature range of molten iron is adjusted to 1475~1510℃ or 1480~1510℃; 2000m 3 The normal range of physical heat control temperature of molten iron in grade blast furnace is usually 1505~1535℃. When smelting green ore with wide melting range, the physical heat control temperature range of molten iron is adjusted to 1510~1535℃ or 1515~1535℃; 3000m 3 The physical heat control temperature range of molten iron in blast furnaces of grade 1 and above is 1510-1540℃. When smelting green ore in the above-mentioned wide melting range, the physical heat control temperature range of molten iron is adjusted to 1515-1540℃ or 1520-1540℃.

[0030] Preferably, the furnace temperature control method also includes increasing the theoretical basicity of the pig iron ore smelting blast furnace by 0.01 to 0.02, for example, it can be 0.01, 0.013, 0.015, 0.018 or 0.02, etc., but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0031] Preferably, the theoretical basicity entering the furnace is 1.195 to 1.205, for example, it can be 1.195, 1.196, 1.198, 1.200, 1.203 or 1.205, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0032] Preferably, the slag management method includes controlling the magnesium-aluminum ratio in the slag to be 0.52 to 0.58, for example, it can be 0.52, 0.53, 0.55, 0.56, 0.57 or 0.58, etc., but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0033] Preferably, the slag management method also includes controlling the mass content of Al2O3 in the slag to be ≤16.5%, for example, it can be 16.5%, 16%, 15.5%, 15%, 14% or 10%, etc., but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0034] Preferably, the method for managing iron out of the furnace includes controlling the iron tapping interval to be 5 to 10 minutes shorter than the normal interval, for example, it can be 5 minutes, 6 minutes, 7 minutes, 8 minutes, 9 minutes or 10 minutes, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0035] The method for managing iron tapping out of the furnace described in the present invention also includes humidifying and cooling the furnace to transition the temperature when the iron tapping interval is too long due to other factors, and at the same time changing the drill bit outside the furnace to a larger size to tap iron, so as to prevent slag iron from causing air flow disturbance inside the blast furnace.

[0036] Preferably, the regular interval time is ≤30 min, for example, it can be 30 min, 25 min, 20 min, 10 min or 5 min, etc., but it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0037] As a preferred technical solution of the present invention, the furnace smelting method includes a material optimization method before the green ore enters the furnace, a green ore batch redesign method, an airflow index control method, a furnace temperature control method, a slag system management method, and a furnace out-of-furnace iron management method;

[0038] The method for optimizing the material system before the green ore is put into the furnace comprises distributing the green ore in the wide soft melting range into the middle annular zone of the material system after the green ore is put into the furnace;

[0039] The green ore batch weight design method includes adopting a small batch fast running method to replace the large batch smelting, and the small batch weight × the number of hourly batches ≥ the large batch weight × the number of hourly batches;

[0040] The airflow index control method includes controlling the edge airflow index W to be 0.65 to 0.95, wherein the edge airflow index W is the ratio of the sum of the temperature values ​​of the four points at the edge of the cross temperature measuring gun in the furnace to the average temperature of the four points on the furnace top riser;

[0041] The method for controlling the airflow index further includes controlling the central airflow index Z to be 6 to 8, wherein the central airflow index Z is the ratio of the sum of the temperature values ​​of the four central points of the cross temperature measuring gun in the furnace to the average temperature of the four points of the furnace top riser;

[0042] The furnace temperature control method includes increasing the lower limit of the molten iron physical heat control by 5 to 10°C;

[0043] The temperature range of the physical heat control of molten iron is related to the furnace capacity of the pig iron ore smelting blast furnace; among them, 1000m 3 The temperature range of the molten iron physical heat control of the blast furnace is 1470~1510℃; 3 The physical heat control temperature range of molten iron in the blast furnace is 1505~1535℃; 3 The physical heat control temperature range of molten iron in blast furnaces above grade 1 is 1510~1540℃;

[0044] The furnace temperature control method further includes increasing the theoretical basicity of the pig iron ore entering the blast furnace by 0.01 to 0.02; the theoretical basicity of the pig iron ore entering the blast furnace is 1.195 to 1.205;

[0045] The slag system management method includes controlling the magnesium-aluminum ratio in the slag to be 0.52 to 0.58;

[0046] The slag system management method further includes controlling the mass content of Al2O3 in the slag to ≤16.5%;

[0047] The method for managing tapping out of the furnace includes controlling the tapping interval to be 5 to 10 minutes shorter than the normal interval; the normal interval is ≤30 minutes;

[0048] The remelting temperature of the pig iron ore in the wide remelting range is 1100-1500° C.; the proportion of the pig iron ore in the wide remelting range charged into the furnace is 5%-10%.

[0049] Compared with the prior art, the present invention has at least the following beneficial effects:

[0050] The method for smelting pig iron ore with a high proportion in a wide soft melting zone provided by the present invention reduces almost all adverse effects after the pig iron ore in the wide soft melting zone is put into the furnace to a minimum through all-round and multi-angle design, fundamentally solving the industry problem of smelting pig iron ore in the wide soft melting zone into the furnace, so that the blast furnace can run smoothly without interference and fuel consumption will not increase significantly. The proportion of pig iron ore in the wide soft melting zone can be stably increased to 5% to 10%, which greatly reduces the blast furnace smelting cost and has broad application prospects. DETAILED DESCRIPTION

[0051] For the convenience of understanding the present invention, the present invention is given below with examples. It should be understood by those skilled in the art that the examples are only for the purpose of helping to understand the present invention and should not be regarded as specific limitations of the present invention.

[0052] The present invention is further described in detail below. However, the following examples are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims.

[0053] Example 1

[0054] This embodiment provides a method for smelting a high proportion of pig iron ore in a wide soft melting range, the method comprising a material optimization method before the green ore is put into the furnace, a green ore batch redesign method, an airflow index control method, a furnace temperature control method, a slag system management method, and a furnace out-of-furnace pig iron management method.

[0055] The remelting temperature of the pig iron ore in the wide remelting range in this embodiment is 1197-1405°C, and the blast furnace capacity is 1050m 3 , the ore batch weight is 33.66t, and the distribution system is shown in Table 1:

[0056] Table 1

[0057]

[0058] The method for optimizing the material system before the green ore is fed into the furnace includes distributing the green ore in the wide soft melting zone into the middle annular belt of the material system after feeding. In this embodiment, the angles of the middle annular belt are controlled to be 41.5° and 39.5° respectively according to the second and third gears of the green ore in the wide soft melting zone in the above table.

[0059] The green ore batch weight design method includes adopting a small batch fast running method to replace the large batch smelting, and the small batch weight × the number of hourly batches ≥ the large batch weight × the number of hourly batches;

[0060] In this embodiment, the batch weight of the large ore is 34t, and the average loading time is 7.25 batches per hour. When the wide soft melting interval green ore is used, the ore batch weight is 33.66t, and the average hourly material rate meets the condition: (34×7.25) / 33.66≥7.32 batches.

[0061] The airflow index control method includes controlling the edge airflow index W to be 0.65 to 0.95, wherein the edge airflow index W is the ratio of the sum of the temperature values ​​of the four points at the edge of the cross temperature measuring gun in the furnace to the average temperature of the four points on the furnace top riser;

[0062] The method for controlling the airflow index further includes controlling the central airflow index Z to be 6 to 8, wherein the central airflow index Z is the ratio of the sum of the temperature values ​​of the four central points of the cross temperature measuring gun in the furnace to the average temperature of the four points of the furnace top riser;

[0063] The furnace temperature control method includes increasing the lower limit of the molten iron physical heat control by 5°C;

[0064] In this embodiment, it is 1000m 3 Grade blast furnace, so the lower limit of its molten iron physical heat control becomes 1475℃.

[0065] The furnace temperature control method further includes increasing the theoretical basicity of the pig iron ore smelting blast furnace by 0.01; at this time, the theoretical basicity of the furnace becomes 1.205-1.215;

[0066] The slag system management method includes controlling the magnesium-aluminum ratio in the slag to be 0.52 to 0.58;

[0067] The slag system management method further includes controlling the mass content of Al2O3 in the slag to ≤16.5%;

[0068] The method for managing iron tapping out of the furnace includes controlling the iron tapping interval to be 5 minutes shorter than the normal interval; the normal interval is ≤30 minutes.

[0069] Example 2

[0070] This embodiment provides a method for smelting a high proportion of pig iron ore in a wide soft melting range, the method comprising a material optimization method before the green ore is put into the furnace, a green ore batch redesign method, an airflow index control method, a furnace temperature control method, a slag system management method, and a furnace out-of-furnace pig iron management method.

[0071] The remelting temperature of the pig iron ore in the wide remelting range in this embodiment is 1100-1500°C, and the blast furnace capacity is 2000m 3 , the ore batch weight is 73t, and the distribution system is shown in Table 2:

[0072] Table 2

[0073]

[0074] The method for optimizing the material system before the green ore is fed into the furnace includes distributing the green ore in the wide soft melting range into the middle annular belt of the material system after feeding. In this embodiment, the angle of the middle annular belt is controlled according to the second and third gears of the green ore in the above table, and the angles are 35.8° and 33.3° respectively.

[0075] The green ore batch weight design method includes adopting a small batch fast running method to replace the large batch smelting, and the small batch weight × the number of hourly batches ≥ the large batch weight × the number of hourly batches;

[0076] In this embodiment, the ore batch weight is 73t, and the average loading time is 6.8 batches per hour. When using green ore in a wide soft melting interval, the ore batch weight is 70t, and the average hourly material rate meets the condition: (73×6.8) / 70≥7.09 batches.

[0077] The airflow index control method includes controlling the edge airflow index W to be 0.65 to 0.95, wherein the edge airflow index W is the ratio of the sum of the temperature values ​​of the four points at the edge of the cross temperature measuring gun in the furnace to the average temperature of the four points on the furnace top riser;

[0078] The method for controlling the airflow index further includes controlling the central airflow index Z to be 6 to 8, wherein the central airflow index Z is the ratio of the sum of the temperature values ​​of the four central points of the cross temperature measuring gun in the furnace to the average temperature of the four points of the furnace top riser;

[0079] The furnace temperature control method includes increasing the lower limit of the molten iron physical heat control by 10°C;

[0080] In this embodiment, it is 2000m 3 Grade blast furnace, so the lower limit of its molten iron physical heat control becomes 1510℃.

[0081] The furnace temperature control method further includes increasing the theoretical basicity of the pig iron ore smelting blast furnace by 0.02; at this time, the theoretical basicity of the furnace becomes 1.215-1.225;

[0082] The slag system management method includes controlling the magnesium-aluminum ratio in the slag to be 0.52 to 0.58;

[0083] The slag system management method further includes controlling the mass content of Al2O3 in the slag to ≤16.5%;

[0084] The method for managing iron tapping out of the furnace includes controlling the iron tapping interval to be 10 minutes shorter than the normal interval; the normal interval is ≤30 minutes.

[0085] It can be seen from Examples 1 to 2 that the present invention has carried out all-round targeted optimization design from six aspects: material system optimization before the green ore in the wide soft melting range is put into the furnace, ore batch weight design, airflow model, furnace temperature control, slag system management and iron ore management outside the furnace. Almost all adverse effects after the green ore in the wide soft melting range with a soft melting temperature of 1100-1500°C is put into the furnace are reduced to a minimum, the proportion of pig iron ore in the wide soft melting range entering the furnace is increased to 5%-10%, the blast furnace smelting cost is low, and the economic benefit is good.

[0086] The applicant declares that the above is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention fall within the scope of protection and disclosure of the present invention.

Claims

1. A method for smelting a high proportion of pig iron ore in a wide melting range, characterized in that: The furnace smelting method includes a material optimization method before the green ore enters the furnace, a green ore batch weight design method, an airflow index control method, a furnace temperature control method, a slag system management method, and an out-of-furnace iron management method; The remelting temperature of the pig iron ore in the wide remelting range is 1100-1500° C.; the proportion of the pig iron ore in the wide remelting range charged into the furnace is 5%-10%.

2. The furnace smelting method according to claim 1, characterized in that: The material system optimization method before the green ore is put into the furnace comprises distributing the green ore in the wide soft melting zone into the middle annular zone of the material system after the green ore is put into the furnace.

3. The furnace smelting method according to claim 1 or 2, characterized in that: The green ore batch weight design method includes adopting a small batch fast running method to replace the large batch smelting in the furnace, and the batch weight of the small ore batch × the number of batches per hour ≥ the batch weight of the large ore batch × the number of batches per hour.

4. The furnace smelting method according to any one of claims 1 to 3, characterized in that: The airflow index control method includes controlling the edge airflow index W to be 0.65-0.95, wherein the edge airflow index W is the ratio of the sum of the temperature values ​​of the four points at the edge of the cross temperature measuring gun in the furnace to the average temperature of the four points of the furnace top riser.

5. The furnace smelting method according to any one of claims 1 to 4, characterized in that: The method for controlling the airflow index also includes controlling the central airflow index Z to be 6 to 8, wherein the central airflow index Z is the ratio of the sum of the temperature values ​​of the four central points of the cross temperature measuring gun in the furnace to the average temperature of the four points of the furnace top riser.

6. The furnace smelting method according to any one of claims 1 to 5, characterized in that: The furnace temperature control method includes increasing the lower limit of the physical heat control of molten iron by 5 to 10°C; Preferably, the temperature range of the physical heat control of the molten iron is related to the furnace capacity of the pig iron ore smelting blast furnace; wherein, 1000m 3 The physical heat control temperature range of molten iron in the blast furnace is 1470~1510℃; 2000m 3 The physical heat control temperature range of molten iron in the blast furnace is 1505~1535℃; 3000m 3 The physical heat control temperature range of molten iron in blast furnaces above grade 1 is 1510~1540℃.

7. The furnace smelting method according to any one of claims 1 to 6, characterized in that: The furnace temperature control method further includes increasing the theoretical basicity of the pig iron ore smelting blast furnace by 0.01 to 0.02; Preferably, the theoretical basicity entering the furnace is 1.195-1.

205.

8. The furnace smelting method according to any one of claims 1 to 7, characterized in that: The slag system management method includes controlling the magnesium-aluminum ratio in the slag to be 0.52-0.

58.

9. The furnace smelting method according to any one of claims 1 to 8, characterized in that: The slag system management method also includes controlling the mass content of Al2O3 in the slag to be ≤16.5%.

10. The furnace smelting method according to any one of claims 1 to 9, characterized in that: The method for managing iron out of the furnace includes controlling the iron tapping interval to be 5 to 10 minutes shorter than the normal interval; Preferably, the regular interval time is ≤30 min.

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