A method for judging blast furnace conditions based on iron reduction degree measurement

Abstract

A method for judging the condition of a blast furnace based on the determination of the degree of reduction of iron relates to the field of blast furnace ironmaking. The method for judging the condition of a blast furnace based on the determination of the degree of reduction of iron is as follows: after the blast furnace is shut down, a sample is taken from the blast furnace to obtain tuyere materials distributed radially along the hearth and then cooled; the tuyere materials are segmented and then slag, iron and coke are separated to obtain tuyere slag and tuyere iron of each section of tuyere material distributed radially along the hearth; the tuyere slag weight ratio is weighed and calculated; the mass of metallic iron and total iron in each section of tuyere iron in the sampling tube is measured, and the degree of reduction of each section of tuyere iron in the sampling tube and the mathematical average of the degree of reduction of each section of tuyere iron are calculated; the condition of the blast furnace is judged according to the weight ratio of tuyere slag and the mathematical average of the degree of reduction of each section of tuyere iron in the sampling tube. The method for judging the condition of a blast furnace based on the determination of the degree of reduction of iron provided in the present application judges the condition of the blast furnace by sampling the slag ratio and the degree of reduction of iron of the tuyere material in the blast furnace.

Description

Technical Field

[0001] The present application relates to the field of blast furnace ironmaking, and in particular to a method for judging the condition of a blast furnace based on the determination of the degree of reduction of iron. Background Art

[0002] Coke, the primary raw material for blast furnace ironmaking, serves as a reducing agent, heat source, carbon source, and structural support. Above the blast furnace tuyere, especially in the dripping zone, iron ore and flux have melted, leaving only the coke as the skeleton supporting the blast furnace charge and withstanding the erosion of molten iron and slag. Therefore, blast furnace coke requires a specific particle size composition and strength to ensure good air permeability within the blast furnace. Blast furnace tuyere coke provides a direct reflection of the material state within the blast furnace and has long been a hot research area of ​​particular interest to ironmakers. The characteristics of blast furnace tuyere materials provide a basis for evaluating the working condition of the hearth and adjusting the charge distribution system.

[0003] However, information such as the amount of primary slag generated inside the blast furnace and the degree of reduction of iron at the tuyere plane is usually difficult to obtain. The furnace condition can only be analyzed based on indicators such as the composition of slag and iron discharged from the iron mouth. This leads to an unclear mechanism for the cause of furnace condition fluctuations and a lack of targeted adjustments to the furnace condition, which in turn leads to long-term furnace condition fluctuations and increased iron costs. In addition, there is little quantitative analysis of slag in blast furnace tuyere materials, and there is a lack of calculation of the metallization rate of tuyere iron, which means that blast furnace operators lack effective means to analyze the internal conditions of the blast furnace. Summary of the Invention

[0004] The purpose of this application is to provide a method for judging the blast furnace condition based on the determination of iron reduction degree, which judges the blast furnace condition by sampling the slag ratio and iron reduction degree of the blast furnace tuyere material, thereby adjusting the performance indicators of the raw fuel in a targeted manner, optimizing the blast furnace operation to make the furnace condition smooth and reduce the fuel ratio.

[0005] This application is implemented as follows:

[0006] The present application provides a method for judging the blast furnace condition based on the determination of the reduction degree of iron, comprising the following steps:

[0007] After the blast furnace is shut down, a sampling tube is inserted horizontally through the tuyere into the blast furnace to the center of the hearth, and the tuyere material distributed along the radial direction of the hearth is sampled from the blast furnace and then cooled.

[0008] The tuyere material in the sampling tube is segmented and then slag, iron and coke are separated to obtain tuyere slag and tuyere iron of each segment of tuyere material distributed along the radial direction of the furnace;

[0009] Weigh and calculate the tuyere slag weight ratio Ps;

[0010] Determine the mass of metallic iron MFe and total iron TFe in each section of tuyere iron in the sampling tube, calculate the reduction degree R of each section of tuyere iron in the sampling tube, and calculate the mathematical average of the reduction degree of each section of tuyere iron in the sampling tube.

[0011] According to the mathematical average of the tuyere slag weight ratio Ps and the reduction degree of each section of the tuyere iron in the sampling tube Determine the blast furnace condition.

[0012] In some optional implementation schemes, the tuyere sleeve of the blast furnace is first removed when sampling, and then a blast furnace tuyere coke sampling machine is used to horizontally insert the sampling tube through the tuyere into the center of the furnace.

[0013] In some optional embodiments, the sampling tube is separated into sections every 0.25-0.5 m.

[0014] In some optional implementation schemes, the tuyere material in the sampling tube is segmented and then subjected to magnetic separation to separate the slag, iron and coke.

[0015] In some optional embodiments, the tuyere slag weight ratio Ps is calculated according to the following formula: Ps=Ws / W; wherein Ws is the total weight of the tuyere slag in the sampling tube, and W is the total weight W of the tuyere material in the sampling tube.

[0016] In some optional embodiments, the reduction degree R of the tuyere iron is the mass ratio of metallic iron MFe to total iron TFe in the tuyere iron.

[0017] In some optional embodiments, when the mathematical average of the reduction degree of each section of tuyere iron in the sampling tube is When the tuyere slag weight ratio Ps is less than 4%, it means that the ore is not fully reduced when it passes through the massive zone, soft melting zone, and dripping zone from top to bottom in the blast furnace and reaches the tuyere plane, resulting in low ore metallization rate and small amount of slag.

[0018] In some optional embodiments, when the mathematical average of the reduction degree of each section of tuyere iron in the sampling tube is When the weight ratio of tuyere slag Ps is less than 4%, the softening start, stabilization and softening end temperatures of blast furnace sintered ore are reduced by 8-10°C.

[0019] In some optional embodiments, when the mathematical average of the reduction degree of each section of tuyere iron in the sampling tube is When the tuyere slag weight ratio Ps is less than 4%, the distribution angle is moved toward the edge and the amount of central coke is reduced to strengthen the central airflow of the blast furnace.

[0020] In some optional embodiments, when the mathematical average of the reduction degree of each section of tuyere iron in the sampling tube is When the tuyere slag weight ratio Ps is less than 4%, the coke thermal strength CSR is increased to above 68%.

[0021] The beneficial effects of the present application are as follows: the method for judging the blast furnace condition based on the determination of the reduction degree of iron provided in the present application comprises the following steps: after the blast furnace is shut down, a sampling tube is horizontally inserted into the interior of the blast furnace through the tuyere to the center of the hearth, and a sample is taken from the blast furnace to obtain tuyere material distributed radially along the hearth and then cooled; the tuyere material in the sampling tube is segmented and then slag, iron and coke are separated to obtain tuyere slag and tuyere iron of each section of tuyere material distributed radially along the hearth; the tuyere slag weight ratio Ps is obtained by weighing and calculating; the mass of metallic iron MFe and total iron TFe in each section of tuyere iron in the sampling tube is measured, the reduction degree R of each section of tuyere iron in the sampling tube is calculated, and the mathematical average value of the reduction degree of each section of tuyere iron in the sampling tube is calculated According to the mathematical average of the tuyere slag weight ratio Ps and the reduction degree of each section of the tuyere iron in the sampling tube Determining blast furnace conditions. The method provided in this application for determining blast furnace conditions based on iron reduction determination determines blast furnace conditions by sampling the slag ratio and iron reduction degree of the blast furnace tuyere material, thereby specifically adjusting the performance indicators of the raw materials and optimizing blast furnace operations to ensure smooth furnace conditions and reduce the fuel ratio. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0023] Figure 1 A flow chart of a method for determining blast furnace conditions based on iron reduction degree determination provided in an embodiment of the present application. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments.

[0025] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for protection, but merely represents selected embodiments of the present application. All other embodiments obtained by persons of ordinary skill in the art based on the embodiments in the present application without creative work are within the scope of protection of the present application.

[0026] In the description of this application, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate the orientation or position relationship that the product of this application is usually placed in when in use. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they should not be understood as a limitation on this application.

[0027] like Figure 1 As shown, the embodiment of the present application provides a method for judging the blast furnace condition based on the determination of the reduction degree of iron, comprising the following steps:

[0028] Step 1: Prepare a sampling tube that can be extended from the tuyere into the center of the hearth along the radial direction of the hearth, separate a section at intervals of 0.25-0.5m in the sampling tube, and then take samples; after the blast furnace is shut down, first remove the tuyere cover of the blast furnace, then use a blast furnace tuyere coke sampling machine to horizontally insert the sampling tube through the tuyere into the center of the hearth, sample the tuyere materials distributed along the radial direction of the hearth from the blast furnace, and then cool them; the tuyere materials include tuyere coke, tuyere slag, and tuyere iron;

[0029] Step 2: The tuyere material in the sampling tube is divided into various compartments and taken out, and then the tuyere coke, tuyere slag and tuyere iron are separated by magnetic separation to obtain the tuyere slag and tuyere iron of each compartment distributed along the radial direction of the furnace;

[0030] Step 3: Weigh the tuyere slag, tuyere iron, and tuyere coke in each compartment distributed radially along the hearth and calculate the total weight W of the tuyere material sampled by the sampling tube and the total weight Ws of the tuyere slag in each compartment in the sampling tube. Further calculate the tuyere slag weight ratio Ps, Ps = Ws / W;

[0031] Step 4: After the tuyere iron of each compartment in the sampling tube is subjected to particle size screening, the tuyere iron samples of each compartment are obtained according to the particle size ratio, reduction, and weighing. The tuyere iron samples of each compartment are crushed in a crusher to less than 120 meshes, and the content of metallic iron MFe and total iron TFe in the tuyere iron samples of each compartment are respectively determined. The reduction degree R of the tuyere iron of each compartment in the sampling tube is calculated. The reduction degree R of the tuyere iron of each compartment is the mass ratio of metallic iron MFe and total iron TFe in the tuyere iron of each compartment. The mathematical average of the reduction degree of the tuyere iron of each compartment in the sampling tube is calculated.

[0032] Step 5: The mathematical average of the reduction degree of each tuyere iron in each compartment of the sampling tube according to the tuyere slag weight ratio Ps To judge the blast furnace condition, the mathematical average of the reduction degree of each interval tuyere iron in the sampling tube is used. When the tuyere slag weight ratio Ps is less than 4%, it means that the ore is not fully reduced when it passes through the massive zone, soft melting zone, and dripping zone from top to bottom in the blast furnace and reaches the tuyere plane, resulting in low ore metallization rate and small amount of slag.

[0033] Step 6: The mathematical average of the reduction degree of each tuyere iron in the sampling tube according to the tuyere slag weight ratio Ps and the reduction degree of each tuyere iron in the sampling tube After judging the blast furnace condition, adjust the blast furnace condition:

[0034] 6.1. When the mathematical average of the reduction degree of each section of tuyere iron in the sampling tube is When the tuyere slag weight ratio Ps is less than 4%, the softening start, stabilization and softening end temperatures of the blast furnace sintered ore are reduced to increase the blast furnace soft melting zone height by 8-10°C.

[0035] 6.2. When the mathematical average of the reduction degree of each section of tuyere iron in the sampling tube is When the tuyere slag weight ratio Ps is less than 4%, adjust the distribution system, move the distribution angle toward the edge, reduce the amount of central coke, appropriately strengthen the central airflow, maintain the uniformity of blast furnace gas flow distribution, control the blast furnace temperature at medium to upper, control the Si content of molten iron at about 0.5%, i.e. 0.48-0.52%, and appropriately increase the molten iron temperature to ensure sufficient physical heat in the hearth.

[0036] 6.3. When the mathematical average of the reduction degree of each section of tuyere iron in the sampling tube is When the tuyere slag weight ratio Ps is less than 4%, the coke thermal strength CSR is increased to above 68%.

[0037] The principle of the method for judging the blast furnace condition based on the determination of the degree of reduction of iron provided in the embodiment of the present application is: the blast furnace soft melting zone is composed of many solid coke layers and semi-molten ore layers bonded together. The coke ore in the blast furnace soft melting zone is alternate and clearly layered. Since the ore is in a soft melting state, the permeability is extremely poor. The coal gas mainly passes through the coke layer like a window, so it is called a "coke window". The upper edge of the blast furnace soft melting zone is the softening line, and the lower edge is the melting line. It is consistent with the soft melting temperature range of the ore. The highest part is called the top of the soft melting zone, and the lowest part is connected to the furnace wall and is called the root of the soft melting zone. As the raw material conditions and operating conditions change, the shape and position of the soft melting zone change accordingly. The reactions occurring in the soft melting zone are mainly the softening of the ore and the formation of primary slag. The low-melting-point compounds formed by the solid-phase reaction begin to soften after further heating. At the same time, the appearance of the liquid phase improves the contact conditions between the ore and the coke or flux. When the charge continues to descend and heat up, the liquid phase continues to increase, and eventually softens and melts to form a flowing state. The softening of the ore to the melting flow is a link in the slag-making process that has a greater impact on the blast furnace's travel. The early or late formation of the initial slag and the high or low position in the blast furnace have a greater impact on the smooth travel of the blast furnace. Therefore, the blast furnace soft melting zone is also called the slag-forming zone. The results of the three-dimensional dynamic simulation experiment on the morphology of the blast furnace soft melting zone in the laboratory conducted by this application show that the use of a charging system with a development center and center coke addition is conducive to the formation of a high-position inverted V-shaped soft melting zone, which can improve the permeability of the charge column and reduce the total pressure drop in the furnace. It is an effective means to increase the amount of coal injection, dredge the gas flow in the furnace, and promote the smooth travel of the blast furnace. Blast furnace tuyere coke can directly reflect the material status in the blast furnace. By detecting the slag ratio and iron reduction degree characteristics of the tuyere material in the blast furnace tuyere, it can provide a basis for judging the working condition of the hearth and adjusting the distribution system, so as to adjust the performance indicators of the raw materials in a targeted manner, optimize the blast furnace operation, make the furnace condition smooth, and reduce the fuel ratio.

[0038] The characteristics and performance of the method for judging the blast furnace condition based on the determination of the iron reduction degree of the present application are further described in detail below with reference to the examples.

[0039] Example 1

[0040] The present invention provides a method for judging the blast furnace condition based on the determination of iron reduction degree, for 4000m 3 The treatment is carried out in a high-grade blast furnace, comprising the following steps:

[0041] Step 1: Prepare a sampling tube that can be extended from the tuyere to the center of the furnace along the radial direction of the furnace hearth by 6.8m. Separate a section every 0.5m in the sampling tube so that the sampled material does not move in the sampling tube, and then take samples. After the blast furnace is shut down, first remove the tuyere sleeve of the blast furnace, then use a blast furnace tuyere coke sampling machine to horizontally insert the sampling tube through the tuyere into the center of the furnace hearth, sample the tuyere materials distributed along the radial direction of the furnace hearth from the blast furnace, and then cool them. The tuyere materials include tuyere coke, tuyere slag, and tuyere iron.

[0042] Step 2: The tuyere material in the sampling tube is divided into various compartments and taken out, and then the tuyere coke, tuyere slag and tuyere iron are separated by magnetic separation to obtain the tuyere slag and tuyere iron of each compartment distributed along the radial direction of the furnace;

[0043] Step 3: Weigh the tuyere slag, tuyere iron, and tuyere coke in each compartment distributed radially along the hearth and calculate the total weight W of the tuyere material sampled by the sampling tube to be 25 kg. Calculate the total weight Ws of the tuyere slag in each compartment in the sampling tube to be 0.75 kg. Further calculate the tuyere slag weight ratio Ps, Ps = Ws / W = 3%;

[0044] Step 4: Use 3mm, 5mm, 10mm, 15mm, and 25mm round hole sieves to screen the tuyere iron in each compartment of the sampling tube, and then reduce and weigh the tuyere iron samples in each compartment according to the particle size ratio. Grind the tuyere iron samples in each compartment to below 120 mesh in a grinder, and determine the content of metallic iron MFe and total iron TFe in the tuyere iron samples in each compartment respectively. Calculate the reduction degree R of the tuyere iron in each compartment of the sampling tube. The reduction degree R of the tuyere iron in each compartment is the mass ratio of metallic iron MFe to total iron TFe in the tuyere iron in each compartment. Calculate the mathematical average of the reduction degree of the tuyere iron in each compartment of the sampling tube.

[0045] Step 5: The mathematical average of the reduction degree of each tuyere iron in each compartment of the sampling tube according to the tuyere slag weight ratio Ps To judge the blast furnace condition, the mathematical average of the reduction degree of each interval tuyere iron in the sampling tube is used. When the tuyere slag weight ratio Ps is less than 4%, it means that the ore is not fully reduced when it passes through the massive zone, soft melting zone, and dripping zone from top to bottom in the blast furnace and reaches the tuyere plane, resulting in low ore metallization rate and small amount of slag. As a result, the tuyere iron needs to be further reduced in the lower part of the furnace hearth, resulting in increased heat consumption in the lower part of the furnace hearth, causing the blast furnace fuel consumption ratio to increase to 525kg / t, unstable furnace conditions, coal ratio of 145kg / t, and easy furnace cooling.

[0046] Step 6: The mathematical average of the reduction degree of each tuyere iron in the sampling tube according to the tuyere slag weight ratio Ps and the reduction degree of each tuyere iron in the sampling tube After judging the blast furnace condition, adjust the blast furnace condition:

[0047] 6.1. When the mathematical average of the reduction degree of each section of tuyere iron in the sampling tube is When the tuyere slag weight ratio Ps is less than 4%, the softening start, stabilization and softening end temperatures of the blast furnace sintered ore are reduced to increase the blast furnace soft melting zone height by 9°C.

[0048] 6.2. When the mathematical average of the reduction degree of each section of tuyere iron in the sampling tube is When the tuyere slag weight ratio Ps is less than 4%, adjust the distribution system, move the distribution angle toward the edge, reduce the amount of central coke, appropriately strengthen the central airflow, maintain the uniformity of blast furnace gas flow distribution, control the blast furnace temperature at medium to upper, control the Si content of molten iron at 0.5%, and appropriately increase the molten iron temperature to ensure sufficient physical heat in the hearth.

[0049] 6.3. When the mathematical average of the reduction degree of each section of tuyere iron in the sampling tube is When the tuyere slag weight ratio Ps is less than 4%, the coke thermal strength CSR is increased to above 68%, and the permeability of the blast furnace charge column is maintained.

[0050] By adjusting the blast furnace conditions, the blast furnace fuel ratio was reduced by about 5kg / t, and the coal ratio was stabilized at about 175kg / t.

[0051] The embodiments described above are part of the embodiments of the present application, rather than all of the embodiments. The detailed description of the embodiments of the present application is not intended to limit the scope of the present application for protection, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

Claims

1. A method for judging blast furnace conditions based on iron reduction degree determination, characterized in that: The following steps are involved: After the blast furnace is shut down, a sampling tube is inserted horizontally through the tuyere into the blast furnace to the center of the hearth, and the tuyere material distributed along the radial direction of the hearth is sampled from the blast furnace and then cooled. The tuyere material in the sampling tube is segmented and then slag, iron and coke are separated to obtain tuyere slag and tuyere iron of each segment of the tuyere material distributed along the radial direction of the furnace; Weigh and calculate the tuyere slag weight ratio Ps; the tuyere slag weight ratio Ps is the ratio of the total weight Ws of the tuyere slag in the sampling tube to the total weight W of the tuyere material in the sampling tube; Determine the mass of metallic iron MFe and total iron TFe in each section of tuyere iron in the sampling tube, calculate the reduction degree R of each section of tuyere iron in the sampling tube, and calculate the mathematical average of the reduction degree of each section of tuyere iron in the sampling tube. The reduction degree R of the tuyere iron is the mass ratio of metallic iron MFe and total iron TFe in the tuyere iron; According to the mathematical average of the tuyere slag weight ratio Ps and the reduction degree of each section of the tuyere iron in the sampling tube Determine the blast furnace condition; when the mathematical average of the reduction degree of each section of the tuyere iron in the sampling tube is When the ore metallization rate is less than 95% and the tuyere slag weight ratio Ps is less than 4%, it means that the ore is not fully reduced when it passes through the massive zone, soft melting zone and dripping zone from top to bottom in the blast furnace and reaches the tuyere plane, resulting in low ore metallization rate and small amount of slag.

2. The method for judging blast furnace conditions based on iron reduction degree measurement according to claim 1, characterized in that: When taking samples, first remove the blast furnace's tuyere sleeve, then use the blast furnace tuyere coke sampling machine to insert the sampling tube horizontally through the tuyere into the blast furnace to the center of the furnace.

3. The method for judging blast furnace conditions based on iron reduction degree measurement according to claim 1, characterized in that: The sampling tube is divided into sections at intervals of 0.25-0.5 m.

4. The method for judging blast furnace conditions based on iron reduction degree measurement according to claim 1, characterized in that: The tuyere material in the sampling tube is segmented and then subjected to magnetic separation to separate slag, iron and coke.

5. The method for judging blast furnace conditions based on iron reduction degree measurement according to claim 1, characterized in that: When the mathematical average of the reduction degree of each section of tuyere iron in the sampling tube is When the slag content is less than 95% and the tuyere slag weight ratio Ps is less than 4%, the softening start, stabilization and softening end temperatures of the blast furnace sintered ore are reduced by 8-10℃.

6. The method for judging blast furnace conditions based on iron reduction degree measurement according to claim 1, characterized in that: When the mathematical average of the reduction degree of each section of tuyere iron in the sampling tube is When the slag weight ratio at the tuyere is less than 95% and the tuyere slag weight ratio Ps is less than 4%, the distribution angle is moved toward the edge and the amount of central coke is reduced to strengthen the central airflow of the blast furnace.

7. The method for judging blast furnace conditions based on iron reduction degree measurement according to claim 1, characterized in that: When the mathematical average of the reduction degree of each section of tuyere iron in the sampling tube is When the slag weight ratio Ps is less than 95% and the tuyere slag weight ratio Ps is less than 4%, the coke thermal strength CSR is increased to more than 68%.

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