A method and system for evaluating the stability of blast furnace slag

Abstract

The present application belongs to the technical field of blast furnace slag, and particularly relates to a stability evaluation method and system for blast furnace slag, which studies the characteristics of blast furnace slag, obtains stability characterization basis of different temperature sections divided by viscosity change according to viscosity-temperature curve, calculates the maximum and minimum range of stability characterization basis of different temperature sections and corresponds to a score range, converts the score range into corresponding indexes of stability characterization basis in different temperature sections, calculates the influence weight of blast furnace slag composition on stability characterization basis in different temperature sections, normalizes each influence weight, and calculates the blast furnace slag stability evaluation index. The present application is applied to blast furnace production practice, is suitable for stability evaluation of all blast furnace slag, comprehensively considers the stability influencing factors of blast furnace slag in different temperature sections in the whole viscosity range, converts the influence indexes of composition on different temperature sections into stability scores according to the weight, quantitatively characterizes the stability of blast furnace slag, guides the slagging system, and selects a reasonable slag composition interval.

Description

Technical Field

[0001] This invention relates to the field of blast furnace slag technology, specifically to a method and system for evaluating the stability of blast furnace slag. Background Technology

[0002] Maintaining stable furnace conditions is the primary task of blast furnace operation and the foundation for achieving efficient, low-consumption, and green smelting. To effectively address the impact of significant fluctuations in raw material quality on blast furnace operation, some steel companies have adjusted the blast furnace burden structure, resulting in substantial changes to the composition of blast furnace slag compared to previous ironmaking processes. As a byproduct of the ironmaking process, the metallurgical properties of blast furnace slag are a crucial factor in maintaining stable blast furnace operation and achieving good technical and economic indicators. As a high-temperature melt, its physicochemical properties are primarily influenced by temperature and composition.

[0003] Existing studies on the stability evaluation of blast furnace slag mainly focus on the high-temperature range above the melting temperature. Most studies qualitatively characterize stability by analyzing the degree of viscosity variation with temperature or the magnitude of superheat. However, changes in blast furnace slag composition have opposite effects on slag stability at different temperature ranges, and their impact on viscosity varies. Using a single index to characterize slag stability across the entire viscosity range does not accurately reflect the actual metallurgical properties of the slag. Currently, comprehensive studies on the stability of different sections of blast furnace slag are scarce, and most stability evaluation methods are qualitative or semi-quantitative. Therefore, it is necessary to consider different stability evaluation indices for different temperature ranges and establish a comprehensive quantitative method for evaluating the stability of blast furnace slag across different sections. Summary of the Invention

[0004] To address the problems existing in the prior art, the main objective of this invention is to propose a method and system for evaluating the stability of blast furnace slag. This method comprehensively considers factors such as the amount of solid phase precipitation, superheat, and viscosity in different temperature ranges across the entire viscosity spectrum, providing an important basis for evaluating the stability of blast furnace slag.

[0005] To address the aforementioned technical problems, according to one aspect of the present invention, the present invention provides the following technical solution:

[0006] A method for evaluating the stability of blast furnace slag, comprising the following steps:

[0007] S1. The characteristics of blast furnace slag are studied, and the stability characterization basis of different temperature ranges divided by viscosity change is obtained based on the viscosity-temperature curve.

[0008] S2. Calculate the maximum and minimum value ranges of the stability characterization criteria for different temperature ranges and convert them into a fractional range [0, 100]. Then, convert this range into the corresponding stability characterization index S for different temperature ranges. i ;

[0009] S3. Calculate the influence weight K of blast furnace slag composition on the stability characterization criteria in different temperature ranges. i ;

[0010] S4. K is obtained by normalizing the weights of each influence. i ';

[0011] S5. The stability evaluation index of blast furnace slag, CTS, is calculated as ∑K. i 'S i .

[0012] As a preferred embodiment of the stability evaluation method for blast furnace slag according to the present invention, in step S1, the different temperature ranges divided by viscosity change are specifically three temperature ranges: T < T 熔化性 T = T 熔化性 , T > T 熔化性 .

[0013] In a preferred embodiment of the stability evaluation method for blast furnace slag according to the present invention, wherein: in step S1, T < T 熔化性 Temperature range: Slag stability is mainly affected by alkalinity. Changes in alkalinity affect the precipitation content of solid particles. Therefore, the change in solid precipitation with temperature fluctuations is used to determine the slag stability. Characterizes the stability of slag in this temperature range.

[0014] In a preferred embodiment of the stability evaluation method for blast furnace slag according to the present invention, wherein: in step S1, T = T 熔化性 Temperature range: Slag stability is mainly affected by alkalinity. Changes in alkalinity affect the types of solid phases that precipitate, resulting in different melting temperatures of the slag. Therefore, the degree of superheat, i.e., Δt, is used to characterize the stability of the slag in this temperature range.

[0015] In a preferred embodiment of the stability evaluation method for blast furnace slag according to the present invention, in step S1, T > T 熔化性 Temperature range: Slag stability is mainly affected by temperature, measured by the magnitude of viscosity change with temperature fluctuations, i.e. This is used to characterize the stability of slag in this temperature range.

[0016] As a preferred embodiment of the stability evaluation method for blast furnace slag described in this invention, in step S2, the calculation of the maximum and minimum value ranges of the stability characterization criteria for different temperature ranges and the corresponding fractional ranges [0, 100] specifically means that the absolute values ​​of the changes in solid phase precipitation, superheat, and viscosity with temperature fluctuations are determined according to the magnitude of the maximum and minimum values, and the index ranges are respectively corresponding to the fractional ranges [0, 100].

[0017] In a preferred embodiment of the stability evaluation method for blast furnace slag according to the present invention, in step S2, the stability characterization within different temperature ranges is based on the corresponding index S. i Specifically, the stability of different temperature ranges is characterized by the fractions that fall within the range of extreme values ​​corresponding to the fraction range [0, 100].

[0018] In a preferred embodiment of the stability evaluation method for blast furnace slag according to the present invention, in step S3, the influence weight K of the blast furnace slag composition on the stability characterization criteria in different temperature ranges is calculated. i Specifically, it refers to the average value of the linear fit of each index under a series of slag compositions within different temperature ranges.

[0019] In a preferred embodiment of the stability evaluation method for blast furnace slag described in this invention, the normalization process in step S4 specifically comprises:

[0020] To solve the above-mentioned technical problems, according to another aspect of the present invention, the present invention provides the following technical solution:

[0021] A stability evaluation system for blast furnace slag, comprising:

[0022] Stability characterization criteria determination module: The characteristics of blast furnace slag are studied, and the stability characterization criteria for different temperature ranges divided by viscosity change are obtained based on the viscosity-temperature curve.

[0023] The stability characterization criteria module determines the corresponding index: it calculates the maximum and minimum value ranges of the stability characterization criteria for different temperature ranges and converts them into a fractional range [0, 100], which is then converted into the corresponding index S for the stability characterization criteria within different temperature ranges. i ;

[0024] The module for determining the influence weights of stability characterization criteria: calculates the influence weight K of blast furnace slag composition on the stability characterization criteria in different temperature ranges. i ;

[0025] Normalization module: K is obtained by normalizing the weights of each influence. i ';

[0026] Module for determining the stability evaluation index of blast furnace slag: The stability evaluation index of blast furnace slag, CTS, is calculated as CTS = ∑K i 'S i .

[0027] The beneficial effects of this invention are as follows:

[0028] This invention proposes a method and system for evaluating the stability of blast furnace slag. It studies the characteristics of blast furnace slag and obtains stability characterization criteria for different temperature ranges divided by viscosity changes based on viscosity-temperature curves. The extreme value ranges of the stability characterization criteria for different temperature ranges are calculated and corresponding to a score range [0, 100], which is then converted into corresponding indices for stability characterization criteria within different temperature ranges. The influence weights of blast furnace slag components on the stability characterization criteria within different temperature ranges are calculated. Each influence weight is normalized, and the stability evaluation index for blast furnace slag is calculated. This invention is applicable to the actual production of blast furnaces and is suitable for evaluating the stability of all blast furnace slags. It comprehensively considers the influencing factors of slag stability in different temperature ranges across the entire viscosity range, and combines the weights of the influence indicators of components on different temperature ranges to convert them into stability scores, quantitatively characterizing slag stability. This evaluation index guides the slag-making process and helps select reasonable slag composition ranges. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0030] Figure 1 This is a viscosity-temperature curve according to an embodiment of the present invention.

[0031] Figure 2 This is a schematic diagram illustrating different temperature ranges defined by viscosity changes in an embodiment of the present invention.

[0032] Figure 3 The corresponding indicators serve as the basis for characterizing the stability of different temperature ranges in embodiments of the present invention.

[0033] Figure 4 The influence weights are used as the basis for stability characterization in different temperature ranges in embodiments of the present invention.

[0034] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0035] The technical solutions described below in conjunction with the embodiments will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] The embodiments of the present invention are based on the high-basicity blast furnace slag composition of a domestic steel enterprise, and a series of slag systems are designed as shown in Table 1.

[0037] Table 1. Composition of slag series (wt%)

[0038]

[0039] A method for evaluating the stability of blast furnace slag is provided, comprising the following steps:

[0040] S1. Study the characteristics of blast furnace slag, based on viscosity-temperature curves (such as...). Figure 1 As shown) different temperature ranges are obtained by dividing the viscosity into different zones (e.g.) Figure 2 The stability characterization basis (as shown) is:

[0041] ①T < T 熔化性 Temperature range: Slag stability is mainly affected by alkalinity. Changes in alkalinity affect the precipitation content of solid particles. Therefore, the change in solid precipitation with temperature fluctuations is used to determine the slag stability. Characterizes the stability of slag in this temperature range.

[0042] ②T=T 熔化性 Temperature range: Slag stability is mainly affected by alkalinity. Changes in alkalinity affect the types of solid phases that precipitate, resulting in different melting temperatures of the slag. Therefore, the degree of superheat, i.e., Δt, is used to characterize the stability of the slag in this temperature range.

[0043] ③T>T 熔化性 Temperature range: Slag stability is mainly affected by temperature, measured by the magnitude of viscosity change with temperature fluctuations, i.e. This is used to characterize the stability of slag in this temperature range.

[0044] S2. Calculate the maximum and minimum value ranges of the stability characterization criteria for different temperature ranges and convert them into a fractional range [0, 100]. Then, convert this range into the corresponding stability characterization index S for different temperature ranges. i ;

[0045] The slag studied had an R = 1.30, Al₂O₃ = 15.5 wt%, and MgO = 8 wt%. The melting temperature T of this quaternary slag system was obtained by plotting the viscosity curve at 135° tangent. 熔化性 =1425℃, calculate the maximum and minimum values ​​of the characterization criteria for each temperature range, determine the corresponding score range [0,100] for each index range, and convert the characterization criteria calculated under the study of slag composition into the number of components;

[0046] ①T<1425℃

[0047] Characterized by the stability of slag in temperature range ①, by Figure 3 The maximum and minimum values ​​of index (a) are obtained. The value range is [0.0174, 0.065], corresponding to the score [0, 100].

[0048] When the temperature is reduced from 1425℃ to 1410℃, the amount of solid phase precipitation changes by 73.6%. At this temperature, [the following text appears to be incomplete and requires further context: "under this composition..."] The corresponding fraction is S1 = 66.39.

[0049] ②T=1425℃

[0050] The superheat Δt characterizes the stability of the slag in temperature range ②. Figure 3 In (b), the superheat range is (52.38, 70.28) corresponding to the fraction [0, 100]. When the basicity is 1.30, the superheat of the slag system is 56.59, which is converted to the corresponding fraction S2 = 23.52.

[0051] ③T>1425℃

[0052] Characterizing the stability of slag in temperature range ③, as shown by... Figure 3 The maximum value of index (c) is obtained. The value range is (0.0014, 0.055), corresponding to the score [0, 100].

[0053] When the temperature is increased from 1425℃ to 1500℃, the viscosity changes by 0.51 Pa·s. For this component... The corresponding fraction is S3 = 10.07.

[0054] S3. Calculate the influence weight K of blast furnace slag composition on the stability characterization criteria in different temperature ranges. i ;

[0055] ①T < T 熔化性 The variation in the amount of solid phase precipitation under different alkalinities is as follows: Figure 4 In (a), the temperature range when the slags of different alkalinities are in a solid-liquid coexistence state is taken, and the amount of solid phase precipitation of slags under different alkalinities is fitted at the average temperature within this temperature range. The absolute value of the average slope of the fitted line is: |K1|=1.95;

[0056] ②T=T 熔化性 The change in superheat under different alkalinities (superheat = actual temperature - melting temperature) is as follows: Figure 4 In (b), the actual temperature is taken as 1500℃, and the absolute value of the slope of the fitted straight line is: |K2|=89.5;

[0057] ③T>T 熔化性 The change in viscosity at high temperatures under different alkalinities is as follows: Figure 4In (c), the viscosity of slags with different alkalinities at high temperatures is fitted, and the absolute value of the average slope of the fitted straight line is taken: |K3|=0.3.

[0058] S4. K is obtained by normalizing the weights of each influence. i ';

[0059]

[0060] S5. The stability evaluation index of blast furnace slag, CTS, is calculated as ∑K. i 'S i .

[0061] The stability evaluation sub-indicators for the slag are R=1.30, Al2O3=15.5wt%, and MgO=8wt%.

[0062]

[0063] The lower the CTS (Chemical Stability Tolerance), the smaller the fluctuation of the corresponding index with temperature and composition, and the higher the slag stability. This slag exhibits high compositional stability.

[0064] This invention is applied to actual blast furnace production and is suitable for evaluating the stability of all blast furnace slags. It comprehensively considers the influencing factors of slag stability across different temperature ranges within the entire viscosity range, and calculates a stability score by weighting the influence of composition on different temperature ranges, thus quantitatively characterizing slag stability. This evaluation index guides the slag-forming process and helps select a reasonable slag composition range.

[0065] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A method for evaluating the stability of blast furnace slag, characterized in that, Includes the following steps: S1. The characteristics of blast furnace slag are studied, and the stability characterization criteria for different temperature ranges divided by viscosity change are obtained based on the viscosity-temperature curve. These different temperature ranges, divided by viscosity change, are specifically three temperature ranges: T < T 熔化性 T=T 熔化性 , T > T 熔化性 ; T < T 熔化性 Temperature range: Slag stability is mainly affected by alkalinity. Changes in alkalinity affect the precipitation content of solid particles. Therefore, the change in solid precipitation with temperature fluctuations is used to determine the slag stability. Characterizes the stability of slag in this temperature range; T = T 熔化性 Temperature range: Slag stability is mainly affected by basicity. Changes in basicity affect the types of solid phases that precipitate, resulting in different melting temperatures of the slag. Therefore, the degree of superheat, i.e., Δt, is used to characterize the stability of the slag in this temperature range. T > T 熔化性 Temperature range: Slag stability is mainly affected by temperature, measured by the magnitude of viscosity change with temperature fluctuations, i.e. To characterize the stability of slag in this temperature range; S2. Calculate the maximum and minimum value ranges of the stability characterization criteria for different temperature ranges and convert them into a fractional range [0, 100]. Then, convert this range into the corresponding stability characterization index S for different temperature ranges. i ; S3. Calculate the influence weight K of blast furnace slag composition on the stability characterization criteria in different temperature ranges. i ; S4. K is obtained by normalizing the weights of each influence. i '; S5. The blast furnace slag stability evaluation index CTS is calculated. .

2. The method for evaluating the stability of blast furnace slag according to claim 1, characterized in that, In step S2, the extreme value range of the stability characterization basis for different temperature ranges is calculated and corresponding to the fractional range [0,100]. Specifically, the absolute values ​​of the changes in solid precipitation, superheat, and viscosity with temperature fluctuation are determined according to the magnitude of the extreme values ​​and correspond to the fractional range [0,100].

3. The method for evaluating the stability of blast furnace slag according to claim 2, characterized in that, In step S2, the stability characterization within different temperature ranges is based on the corresponding index S. i Specifically, the stability of different temperature ranges is characterized by the fractions that fall within the range of extreme values ​​corresponding to the fraction range [0, 100].

4. The method for evaluating the stability of blast furnace slag according to claim 1, characterized in that, In step S3, the influence weight K of the blast furnace slag composition on the stability characterization criteria in different temperature ranges is calculated. i Specifically, it refers to the average value of the linear fit of each index under a series of slag compositions within different temperature ranges.

5. The method for evaluating the stability of blast furnace slag according to claim 4, characterized in that, In step S4, the normalization process specifically involves: K i '= .

6. A stability evaluation system for blast furnace slag, used to implement the stability evaluation method for blast furnace slag according to any one of claims 1-5, characterized in that, include: Stability characterization criteria determination module: The characteristics of blast furnace slag are studied, and the stability characterization criteria for different temperature ranges divided by viscosity change are obtained based on the viscosity-temperature curve. The stability characterization criteria module determines the corresponding index: it calculates the maximum and minimum value ranges of the stability characterization criteria for different temperature ranges and converts them into a fractional range [0, 100], which is then converted into the corresponding index S for the stability characterization criteria within different temperature ranges. i ; The module for determining the influence weights of stability characterization criteria: calculates the influence weight K of blast furnace slag composition on the stability characterization criteria in different temperature ranges. i ; Normalization module: K is obtained by normalizing the weights of each influence. i '; Module for determining the stability evaluation index of blast furnace slag: Calculates the stability evaluation index of blast furnace slag CTS= .

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