Slag stability quantitative characterization method based on blast furnace slag viscosity

Abstract

The invention discloses a quantitative characterization method for slag stability based on blast furnace slag viscosity, which comprises the following steps: carrying out high-temperature viscosity test on slag based on different furnace on-site slag components and production temperatures of an actual blast furnace under the same raw fuel condition to obtain a series of slag viscosities at different temperatures; drawing a 135-degree tangent line of the viscosity-temperature curve to obtain the corresponding slag melting temperature and the corresponding viscosity; according to the obtained actual production slag temperature, the corresponding viscosity is obtained on the viscosity curve, the change of the slag viscosity in the temperature interval from the melting temperature to the actual slag temperature is calculated, and the thermal stability of the blast furnace slag in the high-temperature section is represented by the average value of the change rates of the viscosity change of the slag in different heat times in the high-temperature section along with the temperature change. The quantitative evaluation method suitable for the stability of the blast furnace slag is provided on the basis of the slag viscosity and the slag fluidity, the influence of viscosity change and temperature fluctuation on the stability of the blast furnace slag is quantified, and a theoretical basis is provided for a blast furnace smelting regulation and control technology.

Description

Technical Field

[0001] The invention relates to blast furnace slag, and in particular to a method for quantitatively characterizing slag stability based on blast furnace slag viscosity. Background Art

[0002] Blast furnace slag is an important by-product of the iron-making industry. The main components of blast furnace slag are oxides, with the highest content of SiO2, CaO, Al2O3 and MgO. The cost of blast furnace ironmaking accounts for half of the cost of the entire steel industry. Therefore, if enterprises want to improve their economic benefits, they must reduce the cost of blast furnaces. The main raw materials for steel production are iron ore and coke, but as the price of high-grade ore continues to rise, enterprises will inevitably tend to use cheap low-grade iron ore, thereby saving the cost of raw materials and improving their competitiveness. However, a large amount of low-grade iron ore will affect the smooth operation of blast furnaces.

[0003] At present, large and medium-sized domestic steel companies have been using a large amount of imported ores and low-grade self-produced ores, and the fluidity of slag has been affected to varying degrees. Changes in slag composition cause the viscosity of slag to increase and the fluidity to deteriorate. Especially when the furnace temperature is insufficient, its fluidity drops sharply, not only deteriorating the smooth flow, but also making it difficult to discharge slag and iron. The unstable blast furnace condition leads to large changes in slag fluidity when the slag composition and temperature fluctuate, that is, the slag stability changes significantly. However, there is currently no unified evaluation standard for slag stability in the industry.

[0004] Therefore, it is necessary to develop a targeted slag stability evaluation method to quantitatively evaluate the stability of blast furnace slag and then regulate blast furnace operations. Summary of the invention

[0005] Purpose of the invention: In view of the shortcomings and defects of the prior art, the present invention provides a method for quantitative characterization of slag stability based on blast furnace slag viscosity. Based on the slag viscosity and on the basis of slag fluidity, a quantitative evaluation method for blast furnace slag stability is proposed, which quantifies the effects of viscosity changes and temperature fluctuations on blast furnace slag stability, and provides a theoretical basis for blast furnace smelting control technology.

[0006] Technical solution: A quantitative characterization method for slag stability based on blast furnace slag viscosity of the present invention is characterized by: based on the on-site slag composition and production temperature of different furnaces of an actual blast furnace under the same raw material and fuel conditions, a high-temperature viscosity test is performed on the slag to obtain a series of slag viscosities at different temperatures; the corresponding slag melting temperature and the corresponding viscosity are obtained by making a 135° tangent to the viscosity-temperature curve; the corresponding viscosity is obtained on the viscosity curve according to the actual production slag temperature obtained, the change in slag viscosity in the temperature range from the melting temperature to the actual slag temperature is calculated, and the average value of the rate of change of viscosity of slag from different furnaces in the high temperature section with temperature change is taken to characterize the thermal stability of slag in the high temperature section of blast furnace slag.

[0007] Among them, the actual slag temperature on site and theoretical calculations are combined to evaluate the slag stability and then control the blast furnace operation, adjust the raw material fuel ratio and reduce costs.

[0008] The method for quantitatively characterizing slag stability based on high-furnace slag viscosity of the present invention is characterized by comprising the following steps:

[0009] 1) Take on-site slag samples from different batches of blast furnaces under the same raw fuel conditions;

[0010] 2) Obtain the actual slag temperature T A ;

[0011] 3) Conducting a high temperature viscosity test on the slag to obtain a viscosity-temperature curve;

[0012] 4) Draw a 135° tangent line to the curve to obtain the melting temperature T of the slag of this furnace M And the corresponding viscosity η M ;

[0013] 5) Take the actual slag T on the viscosity-temperature curve A Corresponding viscosity η A ;

[0014] 6) Calculate the slag stability index of the furnace

[0015] 7) Calculate the stability index of the blast furnace slag under the same raw fuel conditions

[0016] Wherein, in the step 1), on-site slag samples of different batches of blast furnaces under the same raw fuel conditions are taken, specifically blast furnace slag of different batches of the same blast furnace under the same raw fuel conditions.

[0017] Wherein, in the step 2), the actual slag temperature T A It is the slag temperature detected on-site in the blast furnace during slag tapping.

[0018] Wherein, in the step 6), in the slag stability index Si, i refers to the i-th heat.

[0019] Wherein, in the step 7), in the slag stability index Si, i refers to the i-th heat; and n refers to the slag from n heats in total.

[0020] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: Based on slag viscosity and slag fluidity, the present invention proposes a stability quantitative evaluation method suitable for blast furnace slag, quantifies the effects of viscosity change and temperature fluctuation on blast furnace slag stability, and provides a theoretical basis for blast furnace smelting control technology. The present invention considers the change of slag viscosity with temperature in the high temperature section, defines a stability index, and thus quantitatively characterizes the stability of blast furnace slag. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural schematic diagram of the present invention. DETAILED DESCRIPTION

[0022] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and specific implementation methods.

[0023] The quantitative characterization method of slag stability based on blast furnace slag viscosity of the present invention is based on the slag composition and production temperature of different furnaces under the same raw fuel conditions in the actual blast furnace, and the slag is subjected to a high temperature viscosity test to obtain a series of slag viscosities at different temperatures; the corresponding slag melting temperature and the corresponding viscosity are obtained by making a 135° tangent to the viscosity-temperature curve; the corresponding viscosity is obtained on the viscosity curve according to the actual production slag temperature obtained, and the change of slag viscosity in the temperature range from the melting temperature to the actual slag temperature is calculated, and the average value of the change rate of viscosity change of slag of different furnaces in the high temperature section with temperature change is taken to characterize the thermal stability of slag in the high temperature section of blast furnace slag. The actual slag temperature on site and theoretical calculation are combined, and the blast furnace operation is regulated and controlled through slag stability evaluation, the raw fuel ratio is adjusted, and the cost is reduced.

[0024] The method for quantitatively characterizing slag stability based on high-furnace slag viscosity of the present invention is characterized by comprising the following steps:

[0025] 1) Take on-site slag samples from different batches of blast furnaces under the same raw fuel conditions; specifically, blast furnace slag from different batches of the same blast furnace under the same raw fuel conditions;

[0026] 2) Obtain the actual slag temperature T A ; Actual slag temperature T A It is the slag temperature detected on site of the blast furnace during slag tapping;

[0027] 3) Conducting a high temperature viscosity test on the slag to obtain a viscosity-temperature curve;

[0028] 4) Draw a 135° tangent line to the curve to obtain the melting temperature T of the slag of this furnace M And the corresponding viscosity η M ;

[0029] 5) Take the actual slag T on the viscosity-temperature curve A Corresponding viscosity η A ;

[0030] 6) Calculate the slag stability index of the furnace i refers to the i-th batch;

[0031] 7) Calculate the stability index of the blast furnace slag under the same raw fuel conditions i refers to the i-th heat; n refers to the slag from n heats in total.

[0032] The present invention is based on slag viscosity and slag fluidity to propose a stability quantitative evaluation method suitable for blast furnace slag, quantify the influence of viscosity change and temperature fluctuation on blast furnace slag stability, and provide a theoretical basis for blast furnace smelting control technology. The present invention considers the change of slag viscosity in the high temperature section with temperature, defines a stability index, and thus quantitatively characterizes the stability of blast furnace slag.

[0033] The present invention is applied to the actual blast furnace production, and comprehensively considers the fluidity and stability of the slag to establish a scientific slag stability quantitative characterization method based on the viscosity of the blast furnace slag, so as to ensure that the slag can flow freely in the blast furnace, and quantitatively evaluate the stability of the blast furnace slag so as to make timely regulation and control, thereby facilitating efficient, low-carbon, safe and stable production and smelting of the blast furnace.

[0034] According to calculations, based on a daily output of 5,300 t, a slag ratio of 330 kg / t, a comprehensive reduction in coke ratio of 1-2 kg / t, a coke unit price of 1,500 yuan / t, and a blast furnace operating rate of 95%, the economic benefits of a blast furnace increased by one year: 5,200 t / day × (1-2) kg / t × 95% × 365 days × 1,500 yuan / t = 2.7 million to 5.4 million yuan.

Claims

1. A quantitative characterization method for slag stability based on high-furnace slag viscosity, characterized in that: Based on the actual blast furnace on-site slag composition and production temperature of different furnaces under the same raw material and fuel conditions, a high-temperature viscosity test was carried out on the slag to obtain a series of slag viscosities at different temperatures; the corresponding slag melting temperature and corresponding viscosity were obtained by making a 135° tangent to the viscosity-temperature curve; according to the actual production slag temperature, the corresponding viscosity was obtained on the viscosity curve, and the change of slag viscosity in the temperature range from the melting temperature to the actual slag temperature was calculated, and the average value of the change rate of viscosity of slag from different furnaces in the high temperature section with temperature change was taken to characterize the thermal stability of blast furnace slag in the high temperature section.

2. The method for quantitatively characterizing slag stability based on high-furnace slag viscosity according to claim 1, characterized in that: Based on the actual slag temperature on site and theoretical calculations, the blast furnace operation is regulated and the raw material fuel ratio is adjusted through slag stability evaluation.

3. The method for quantitatively characterizing slag stability based on high-furnace slag viscosity according to claim 1 or 2, characterized in that: The steps include: 1) Take on-site slag samples from different batches of blast furnaces under the same raw fuel conditions; 2) Obtain the actual slag temperature T A ; 3) Conducting a high temperature viscosity test on the slag to obtain a viscosity-temperature curve; 4) Draw a 135° tangent line to the curve to obtain the melting temperature T of the slag of this furnace M And the corresponding viscosity η M ; 5) Take the actual slag T on the viscosity-temperature curve A Corresponding viscosity η A ; 6) Calculate the slag stability index of the furnace 7) Calculate the stability index of the blast furnace slag under the same raw fuel conditions 4. The method for quantitatively characterizing slag stability based on high-furnace slag viscosity according to claim 3, characterized in that: In the step 1), on-site slag samples are taken from different batches of blast furnaces under the same raw fuel conditions, specifically blast furnace slag from different batches of the same blast furnace under the same raw fuel conditions.

5. The method for quantitatively characterizing slag stability based on high-furnace slag viscosity according to claim 3, characterized in that: In the step 2), the actual slag temperature T A It is the slag temperature detected on-site in the blast furnace during slag tapping.

6. The method for quantitatively characterizing slag stability based on blast furnace slag viscosity according to claim 3, characterized in that: In the step 6), in the slag stability index Si, i refers to the i-th heat.

7. The method for quantitatively characterizing slag stability based on blast furnace slag viscosity according to claim 3, characterized in that: In the step 7), in the slag stability index Si, i refers to the i-th heat; n refers to the slag from n heats in total.

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