Recognition Method and Slag Hanging Method for the Slag Hanging Effect at the Converter Bottom

Abstract

The present invention discloses a method for identifying the slag hanging effect on the bottom of a converter and a slag hanging method. The method steps are as follows: 1) After the slag hanging on the bottom of the converter is completed, the converter is rotated to the zero position; 2) Adjust the opening degree of the valve of the main gas supply pipe of the central pipe of the bottom lance to generate a pressure pulse wave in the gas supply pressure of the bottom lance; 3) During the valve adjustment, collect the pressure data of the main gas supply pipe of the central pipe and the pressure data of the ring gap of each bottom lance; respectively perform parabolic fitting on the pressure data of the main gas supply pipe of the bottom lance and the pressure data of the ring gap pipe gas supply; 4) Compare the pressure pulse wave data of the central pipe and the ring gap of the bottom lance, and calculate the slag hanging effect index through a quantitative evaluation of the slag hanging effect equation; 5) Determine the slag hanging effect through the index E d If 0.20 < E d ≤ 0.60, it indicates that the slag hanging effect is good. The present invention can reasonably control the thickness of the slag layer hanging on the mushroom head of the bottom lance, improve the slag hanging effect, help the slag layer to cover and protect the mushroom head, and further maintain the stable operation of the bottom lance and extend the service life of the bottom lance.

Description

Technical Field

[0001] The present invention relates to the technical field of steelmaking, and in particular to a method for identifying the slag hanging effect on the bottom of a converter and a slag hanging method. Background Art

[0002] The smelting advantages of the combined blowing converter with bottom blowing oxygen and bottom powder injection are generally recognized by scholars and practitioners. Due to the strong bottom stirring and bottom lime powder injection, the blowing process of the bottom blowing converter is stable, not easy to splash, and the metal yield can be improved; the high secondary combustion rate can increase the scrap ratio charged into the furnace; the strong bottom stirring improves the reaction kinetics, thereby reducing the consumption of quicklime and the oxidizability of the final slag; at the same time, the carbon-oxygen reaction at the end point is close to equilibrium, having a lower carbon-oxygen product. Therefore, the excellent metallurgical indexes of the combined blowing converter with bottom blowing oxygen and bottom powder injection have attracted wide attention from metallurgical practitioners.

[0003] However, the bottom blowing oxygen and strong stirring exacerbate the erosion of the refractory on the furnace bottom, making the service life of the furnace bottom refractory significantly lower than that of the lining refractory. Industrial practice has found that the average service life of the furnace bottom is 1500 heats, and the lowest is 800 heats. With the gradual maturity of the slag splashing and lining protection technology, it is expected to extend the service life of the bottom blowing converter by optimizing the slag splashing and slag hanging operations. Multifaxco in Canada implements selective slag splashing and slag hanging according to the steel grade and end point conditions, and the furnace bottom life can be extended to 2400 heats, with remarkable results. In fact, the effects of slag splashing on the lining and slag hanging on the furnace bottom are mainly qualitatively judged by technicians through visual observation combined with experience, and the long-term slag splashing effect is evaluated by the wear of the lining and furnace bottom refractories. At present, for converters, especially bottom blowing converters, there is a lack of a rapid and quantitative identification method for the slag splashing and slag hanging effects on the furnace bottom, resulting in the inability to timely adjust and optimize the slag splashing and slag hanging schemes of the converter, leading to faster wear and lower service life of the converter refractories. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a rapid, quantitative and effective method for identifying the slag hanging effect on the bottom of a converter; the present invention also provides a slag hanging method for a converter.

[0005] To solve the above technical problems, the method steps taken by the present invention are as follows:

[0006] 1) After the slag hanging on the bottom of the converter is completed, the converter is rotated to the zero position;

[0007] 2) Adjust the opening of the main gas supply pipe valve of the central pipe of the bottom lance to generate a pressure pulse wave in the gas supply pressure of the bottom lance. The valve openings are the original opening C0 and the adjusted valve opening C respectively; the adjusted valve opening C = C0*(1 + S), where S ranges from 0.5% to 5%;

[0008] 3) During the valve adjustment, collect the pressure data of the central pipe gas supply main pipe and the circumferential seam pressure of each bottom lance; perform parabolic fitting on the pressure data of the central pipe gas supply main pipe and the circumferential seam pipe gas supply pressure of the bottom lance respectively. The function of the pressure pulse wave j of the central pipe gas supply main pipe changing with time is denoted as P j c (t), and the function of the pressure pulse wave j of the circumferential seam pipe gas supply pressure changing with time is denoted as P ij s (t);

[0009] 4) Compare the pressure pulse wave data of the central pipe of the bottom lance and the circumferential seam, and calculate the slagging effect index through the quantitative evaluation slagging effect equation formula (4):

[0010]

[0011] In the formula and are solved by the following formula (5), and are solved by the following formula (6):

[0012]

[0013]

[0014] Among them, P0 c is the pressure of the central pipe gas supply main pipe when the opening of the central pipe gas supply main pipe valve is C0, and P0 s is the circumferential seam gas supply pressure of the bottom lance i when the opening of the central pipe gas supply main pipe valve is C0;

[0015] 5) Judge the slagging effect through the index E d calculated by formula (4). If 0.20 < E d ≤0.60, it means that the slagging effect is good.

[0016] Furthermore, the following steps are also provided between steps 3) and 4): Calculate the effective index according to the extreme points of the pressure pulse wave, and the calculation method is as follows formula (1):

[0017]

[0018] In the formula, represents the time corresponding to the extreme value of the pressure pulse wave j of the central pipe gas supply main pipe, and is solved by the following formula (2); represents the time corresponding to the extreme value of the pressure pulse wave j of the circumferential seam of the bottom lance i, and is solved by the following formula (3); m represents the number of bottom lances at the furnace bottom; n represents the number of pressure pulse waves generated by adjusting the valve;

[0019]

[0020]

[0021] If 0 ≤ E f ≤ 15 s, it is determined as valid and the subsequent steps are carried out.

[0022] Furthermore, in the step 2), the time for adjusting the valve opening once is controlled within 4 s to 6 s, and the adjustment interval time is controlled within 1 s to 3 s.

[0023] Furthermore, in the step 2), the flow rate of the central lance central pipe at the original opening C0 is 25 Nm 3 / min to 40 Nm 3 / min.

[0024] For the slag hanging method of the present invention, the above recognition method is adopted for recognition. If 0 < E d ≤ 0.20, the slag hanging operation is increased by 1 to 2 times; if 0.20 < E d ≤ 0.60, the smelting of the next furnace is carried out; if 0.60 < E d ≤ 1, the gas supply flow rate of the bottom lance ring gap is reduced by 10% to 15% during the smelting of the next furnace.

[0025] The beneficial effects of adopting the above technical solutions are as follows: 1. The present invention quantifies the slag hanging effect at the furnace bottom through a mathematical model, and guides and optimizes the slag hanging operation and the bottom furnace gas supply through the quantification result, improving the maintenance of the furnace bottom refractories. 2. The present invention does not need to add other equipment, realizes the recognition of the slag hanging effect relying on the bottom furnace gas supply equipment itself, has low operation cost and is simple to implement. 3. The present invention can reasonably control the thickness of the slag layer on the bottom lance mushroom head, improve the slag hanging effect, contribute to the slag layer covering and protecting the mushroom head, and further maintain the stable operation of the bottom lance and extend the service life of the bottom lance. 4. The present invention can timely recognize the slag hanging effect at the furnace bottom after the slag splashing process, and give a quantitative recognition result and operation guidance to achieve the purpose of reducing the wear rate of the furnace bottom refractories and extending the service life of the furnace bottom. Description of the Drawings

[0026] The following further describes the present invention in detail in conjunction with the drawings and specific embodiments.

[0027] Figure 1 It is a schematic diagram of the pressure fluctuation data of the central pipe gas supply main pipe and the ring gap pressure of each bottom lance collected in Embodiment 1 of the present invention. Specific Embodiments

[0028] The following further describes the present invention in detail in conjunction with specific embodiments.

[0029] Method for identifying slag attachment effect on bottom of converter and slag attachment method. After the slag attachment on the converter is completed, by adjusting the gas supply parameters of the bottom lance, a pressure pulse wave is formed in the bottom lance gas supply pressure data. Then, function fitting is performed on the pulse wave to obtain the function equation of the pulse wave. Based on the function of the gas supply main pipe of the central pipe of the bottom lance and the pressure pulse wave of the annular gap gas supply of the bottom lance, an equation is constructed to screen and identify the effective pulse wave for the slag attachment effect, and the slag attachment effect on the bottom of the furnace is calculated and identified based on the effective pulse wave, and quantified by using the slag attachment effect index, which is particularly applicable to the bottom-blown oxygen and bottom-sprayed powder converter. This identification method includes the following steps:

[0030] 1) Several bottom lances are provided at the bottom of the converter furnace. Each bottom lance is composed of two concentric pipes. The inner pipe is the central pipe, and an annular gap is formed between the outer pipe and the inner pipe. A central pipe gas supply main pipe is provided to supply gas to the central pipes of each bottom lance. A valve is provided on the central pipe gas supply main pipe. The central pipe gas supply main pipe evenly distributes the flow to the central pipes of each bottom lance at the bottom of the furnace through a distributor and branch pipelines at the bottom of the furnace, and no separate valve is provided for the central pipe of each bottom lance. The annular gap pipes of each bottom lance are supplied with gas by other pipelines, and an annular gap valve is separately provided for the annular gap of each bottom lance at the bottom of the furnace. The annular gap valve is the gas supply valve for the annular gap of each bottom lance.

[0031] After the slag attachment on the converter is completed, the converter is tilted to the zero position. The gas supply type at the bottom of the furnace is set to nitrogen. The gas flow rate of the central pipe of each bottom lance at the bottom of the furnace is between 25 Nm 3 / min and 40 Nm 3 / min, and the gas flow rate of the annular gap of each bottom lance is controlled between 4% and 7% of the gas flow rate of the central pipe of this bottom lance. At this time, the opening of the valve of the central pipe gas supply main pipe is the original opening C0.

[0032] 2) Adjust the opening of the valve of the central pipe gas supply main pipe to control the gas supply pressure and flow rate parameters. The valve opening is adjusted based on the original opening C0, and a pressure pulse wave is generated in the gas supply pressure data of the central pipe gas supply main pipe and the annular gap of the bottom lance. The adjustment range S of the valve is between 0.5% and 5%, that is, the adjusted valve opening C = C0*(1 + S).

[0033] Adjusting the opening of the valve of the central pipe gas supply main pipe from C0 to C and then back to C0 is recorded as one adjustment. The time for one adjustment of the valve opening is controlled within 4 s to 6 s, the adjustment interval time is controlled within 1 s to 3 s, and the number of pressure pulse waves generated by adjusting the valve is controlled within 3 to 5. During the adjustment of the valve of the central pipe gas supply main pipe, the gas supply valve of the annular gap of the bottom lance is fixed to ensure that the annular gap flow rate remains unchanged.

[0034] 3) During the adjustment of the central pipe main gas supply valve, collect the data of the central pipe main gas supply pressure and the pressure of each bottom lance ring seam, and detect and record the data and corresponding time of the pressure pulse wave of the central pipe main gas supply and the bottom lance ring seam gas supply pressure; respectively perform parabolic fitting on the data of the main gas supply pressure of the bottom lance and the ring seam pipe gas supply pressure to obtain a quadratic function. The function of the pressure pulse wave j of the main gas supply pipe changing with time is denoted as The function of the pressure pulse wave j of the ring seam pipe of the bottom lance i changing with time is denoted as where t is the time, in units of s, and the bottom lance i represents the i-th bottom lance.

[0035] 4) Judge the effectiveness of identifying the slagging effect by the pressure pulse wave. Calculate the effective index based on the extreme points of the pressure pulse wave. The calculation method is as follows in formula (1):

[0036]

[0037] In the formula, represents the time corresponding to the extreme value of the pressure pulse wave j of the central pipe main gas supply, and is solved by the following formula (2); represents the time corresponding to the extreme value of the pressure pulse wave j of the ring seam pressure of the bottom lance i, and is solved by the following formula (3); m represents the number of bottom lances at the furnace bottom; n represents the number of pressure pulse waves generated by adjusting the central pipe main gas supply valve;

[0038]

[0039]

[0040] If 0 ≤ E f ≤ 15 s, it is determined to be effective, and proceed to the following step 5); if E f exceeds the range of 0 to 15 s, it is determined to be invalid, and repeat steps 2) to 4).

[0041] 5) Compare the data of the pressure pulse waves of the bottom lance central pipe and the ring seam, and calculate the slagging effect index through the quantitative evaluation slagging effect equation, as shown in the following formula (4):

[0042]

[0043] In the formula and are solved by the following formula (5), and are solved by the following formula (6):

[0044]

[0045]

[0046] Among them, is the pressure of the central pipe gas supply main pipe when the valve opening of the central pipe gas supply main pipe is C0, unit: MPa; is the annular gap gas supply pressure of lance i when the valve opening of the central pipe gas supply main pipe is C0, unit: MPa.

[0047] 6) The exponent E calculated by formula (4) d Judge the slag hanging effect, the exponent is between 0 and 1.0; if the exponent 0.20 < E d ≤ 0.60, it means that the slag hanging effect is good; the larger the exponent E d is, the thicker the slag on the furnace bottom is, and the worse the air permeability of the mushroom head is; the smaller it is, the thinner the slag on the furnace bottom is, which is not conducive to protecting the mushroom head and the furnace bottom.

[0048] The slag hanging method of this converter is based on the above-mentioned slag hanging effect identification method, and is guided by the exponent E calculated by formula (4) in step 5) above: if 0 < E d ≤ 0.20, indicating that the slag hanging effect is poor, then increase the slag hanging operation 1 - 2 times; if 0.20 < E d ≤ 0.60, indicating that the slag hanging effect is excellent, then directly carry out the smelting of the next heat; if 0.60 < E d ≤ 1, indicating that the slag hanging is too thick, then during the smelting of the next heat, the annular gap gas supply flow rate of the bottom lance is reduced by 10% - 15% on the basis of the conventional flow rate. d ≤ 1, indicating that the slag hanging is too thick, then during the smelting of the next heat, the annular gap gas supply flow rate of the bottom lance is reduced by 10% - 15% on the basis of the conventional flow rate.

[0049] Example 1: The method for identifying the slag hanging effect and the slag hanging method of the bottom blown oxygen and powder injection converter furnace bottom are described as follows.

[0050] The converter is a 260t bottom blown oxygen and powder injection combined blown converter, and the furnace bottom is equipped with 6 bottom lances. After the slag hanging at the furnace bottom of the converter is completed, the converter is swung to the zero position. Set the gas supply type of the bottom lance at the furnace bottom as nitrogen. Among them, the flow rate of the central pipe of the bottom lance is 25 Nm 3 / min, and the annular gap gas flow rate is 5% of the central pipe flow rate. Adjust the valve opening of the central pipe gas supply main pipe, and the adjustment range S is 5%. After adjustment, the valve opening C = C0 * (1 + 5%); the time for adjusting the valve opening once is controlled within 5 s, the time interval between two adjustments is controlled within 2 s, and the number of pressure pulse waves generated by adjusting the valve is controlled within 3. Collect the pressure fluctuation data of the central pipe gas supply main pipe of the bottom lance and the annular gap pressure of each bottom lance, as Figure 1 shown. Respectively perform parabolic fitting on the pressure data of the central pipe gas supply main pipe of the bottom lance and the annular gap pipe gas supply pressure of each lance, and calculate the time corresponding to the extreme value of the wave function. The results are shown in Table 1 below.

[0051] Table 1: List of pressure pulse wave fitting functions

[0052]

[0053]

[0054] The effectiveness of the pressure pulse wave for identifying the slagging effect is calculated using the above formulas (1)-(3), and E is obtained f = 3.47 s; the slagging effect index E is calculated using the above formulas (4)-(6) d Judge the slagging effect: E d = 0.24, and the slagging effect is good.

[0055] Example 2: The method for identifying the slagging effect of the bottom of a bottom-blowing oxygen and powder-injecting converter and the slagging method are as follows.

[0056] The converter is a 260 t bottom-blowing oxygen and powder-injecting combined-blowing converter, and 6 bottom guns are equipped at the bottom of the furnace. After the slagging at the bottom of the converter furnace is completed, the converter is rotated to the zero position. The gas supply type of the bottom guns at the bottom of the furnace is set to nitrogen. Among them, the flow rate of the central pipe of the bottom gun is 30 Nm 3 / min, and the annular gap gas flow rate is 4% of the central pipe flow rate. Adjust the opening degree of the main valve of the central pipe gas supply, and the adjustment range S is 1.5%. After adjustment, the valve opening degree C = C0*(1 + 1.5%); the time for adjusting the valve opening once is controlled within 6 s, the time interval between two adjustments is controlled within 2 s, and the number of pressure pulse waves generated by adjusting the valve is controlled within 5. Collect the pressure fluctuation data of the main gas supply pipe of the central pipe of the bottom gun and the annular gap pressure of each bottom gun, and perform parabolic fitting on the pressure data of the main gas supply pipe of the central pipe of the bottom gun and the annular gap pipe gas supply of the bottom gun respectively. The effectiveness of the pressure pulse wave for identifying the slagging effect is calculated using the above formulas (1)-(3), and E is obtained f = 7.56 s; the slagging effect index E is calculated using the above formulas (4)-(6) d Judge the slagging effect: E d = 0.55, the slagging effect is excellent, and continue with the smelting of the next heat.

[0057] Example 3: The method for identifying the slagging effect of the bottom of a bottom-blowing oxygen and powder-injecting converter and the slagging method are as follows.

[0058] The converter is a 260 t bottom-blowing oxygen and powder-injecting combined-blowing converter, and 6 bottom guns are equipped at the bottom of the furnace. After the slagging at the bottom of the converter furnace is completed, the converter is rotated to the zero position. The gas supply type of the bottom guns at the bottom of the furnace is set to nitrogen. Among them, the flow rate of the central pipe of the bottom gun is 40 Nm 3 / min, the annular gap gas flow rate is 7% of the central pipe flow rate. Adjust the opening of the main valve of the central pipe gas supply, and the adjustment range S is 0.5%. After adjustment, the valve opening C = C0*(1 + 0.5%); the time for adjusting the valve opening once is controlled within 4 s, the time interval between two adjustments is controlled within 3 s, and the number of pressure pulse waves generated by adjusting the valve is controlled within 4. Collect the pressure fluctuations of the main pipe of the central pipe gas supply of the bottom lance and the annular gap pressure of each bottom lance. Perform parabolic fitting on the data of the main pipe pressure of the central pipe gas supply and the annular gap pipe gas supply pressure of the bottom lance respectively. Calculate the effectiveness E of the pressure pulse wave for identifying the slag attachment effect using the above formulas (1)-(3) f = 12.38 s; calculate the slag attachment effect index E using the above formulas (4)-(6) d Judge the slag attachment effect: E d = 0.85, the slag attachment is too thick, and during the smelting process of the next heat, the gas supply flow rate of the annular gap of the bottom lance is reduced by 10% based on the original flow rate.

[0059] Example 4: The method for identifying the slag attachment effect and the slag attachment method of the bottom of this bottom-blowing oxygen and powder-injecting converter are as described below.

[0060] The converter is a 260 t bottom-blowing oxygen and powder-injecting combined-blown converter, and 6 bottom lances are equipped at the bottom of the furnace. After the slag attachment at the bottom of the converter is completed, the converter is tilted to the zero position. Set the gas supply type of the bottom lance at the bottom of the furnace to nitrogen. Among them, the flow rate of the central pipe of the bottom lance is 30 Nm 3 / min, the annular gap gas flow rate is 6% of the central pipe flow rate. Adjust the opening of the main valve of the central pipe gas supply, and the adjustment range S is 2%. After adjustment, the valve opening C = C0*(1 + 2%); the time for adjusting the valve opening once is controlled within 4 s, the time interval between two adjustments is controlled within 1 s, and the number of pressure pulse waves generated by adjusting the valve is controlled within 3. Collect the pressure fluctuations of the main pipe of the central pipe gas supply of the bottom lance and the annular gap pressure of each bottom lance, and perform parabolic fitting on the data of the main pipe pressure of the central pipe gas supply and the annular gap pipe gas supply pressure of the bottom lance respectively. Calculate the effectiveness E of the pressure pulse wave for identifying the slag attachment effect using the above formulas (1)-(3) f = 11.29 s; calculate the slag attachment effect index E using the above formulas (4)-(6) d Judge the slag attachment effect: E d = 0.45, the slag attachment effect is excellent, and continue with the smelting of the next heat.

[0061] Example 5: The method for identifying the slag attachment effect and the slag attachment method of the bottom of this bottom-blowing oxygen and powder-injecting converter are as described below.

[0062] The converter is a 260 t bottom-blowing oxygen and powder-injecting combined-blown converter, and 6 bottom lances are equipped at the bottom of the furnace. After the slag attachment at the bottom of the converter is completed, the converter is tilted to the zero position. Set the gas supply type of the bottom lance at the bottom of the furnace to nitrogen. Among them, the flow rate of the central pipe of the bottom lance is 35 Nm 3 / min, the annular gap gas flow rate is 4.5% of the central pipe flow rate. Adjust the opening degree of the valve of the central pipe gas supply main pipe, and the adjustment range S is 4%. After adjustment, the valve opening degree C = C0 * (1 + 4%); the time for adjusting the valve opening degree once is controlled at 4.5 s, the time interval between two adjustments is controlled at 1.5 s, and the number of pressure pulse waves generated by adjusting the valve is controlled at 4. Collect the pressure fluctuation data of the central pipe gas supply main pipe of the bottom lance and the annular gap pressure of each bottom lance, and perform parabolic fitting on the pressure data of the central pipe gas supply main pipe and the annular gap pipe gas supply pressure of the bottom lance respectively. Calculate the effectiveness E of the pressure pulse wave for identifying the slagging effect by using the above formulas (1)-(3). f = 13.63 s; calculate the slagging effect index E by using the above formulas (4)-(6). d Judge the slagging effect: E d = 0.91, the slag is too thick. In the smelting process of the next heat, the annular gap gas supply flow rate of the bottom lance is reduced by 15% based on the original flow rate.

[0063] Example 6: The method for identifying the slagging effect and the slagging method of the bottom of the bottom-blown oxygen and powder-injected converter are as described below.

[0064] The converter is a 260 t bottom-blown oxygen and powder-injected combined blowing converter, and 6 bottom lances are equipped at the bottom of the furnace. After the slagging at the bottom of the converter furnace is completed, the converter is tilted to the zero position. Set the gas supply type of the bottom lance at the bottom of the furnace to nitrogen. Among them, the central pipe flow rate of the bottom lance is 40 Nm 3 / min, and the annular gap gas flow rate is 6% of the central pipe flow rate. Adjust the opening degree of the valve of the central pipe gas supply main pipe, and the adjustment range S is 3%. After adjustment, the valve opening degree C = C0 * (1 + 3%); the time for adjusting the valve opening degree once is controlled at 5 s, the time interval between two adjustments is controlled at 1 s, and the number of pressure pulse waves generated by adjusting the valve is controlled at 3. Collect the pressure fluctuation data of the central pipe gas supply main pipe of the bottom lance and the annular gap pressure of each bottom lance, and perform parabolic fitting on the pressure data of the central pipe gas supply main pipe and the annular gap pipe gas supply pressure of the bottom lance respectively. Calculate the effectiveness E of the pressure pulse wave for identifying the slagging effect by using the above formulas (1)-(3). f = 11.20 s; calculate the slagging effect index E by using the above formulas (4)-(6). d Judge the slagging effect: E d = 0.56, the slagging effect is excellent, and continue with the smelting of the next heat.

[0065] Long-term application case: Long-term application in a 260-ton bottom-blown oxygen and powder-injected combined blowing converter at a steel plant in Hebei. After statistics, before the implementation of this method, the average wear rate of the bottom refractories was 1.1 mm / furnace, and the minimum wear rate was 0.95 mm / furnace. Using this method to control continuous smelting for more than 2,000 furnace charges, the average wear rate of the bottom refractories was 0.92 mm / furnace, and the minimum wear rate was 0.63 mm / furnace, effectively suppressing the wear rate of the furnace bottom. In summary, this method is applicable to identifying the slagging effect on the bottom of the bottom-blown oxygen and bottom-powder-injected converter. Taking measures based on the identification results can achieve the purpose of suppressing the wear of the furnace bottom and extending the life of the furnace bottom.

Claims

1. A method for identifying the slag hanging effect on the bottom of a converter, characterized in that, The method steps are as follows: 1) A number of bottom lances are provided at the bottom of the converter. Each bottom lance is composed of two concentric tubes. The inner tube is the central tube, and an annular gap is formed between the outer tube and the inner tube. A central tube gas supply main pipe is provided to supply gas to the central tubes of each bottom lance. A valve is provided on the central tube gas supply main pipe. The central tube gas supply main pipe evenly distributes the flow to the central tubes of each bottom lance at the bottom of the furnace through a distributor and branch pipelines at the bottom of the furnace. No individual valve is provided for the central tube of each bottom lance. The annular gap tubes of each bottom lance are supplied with gas by other pipelines. An annular gap valve is separately provided for the annular gap of each bottom lance at the bottom of the furnace. The annular gap valve is the gas supply valve for the annular gap of each bottom lance. After slag hanging at the bottom of the converter furnace is completed, the converter is rotated to the zero position. 2) Adjust the opening degree of the valve of the central tube gas supply main pipe of the bottom lance to generate a pressure pulse wave in the gas supply pressure of the bottom lance. The opening degrees of the valve are the original opening degree C0 and the adjusted valve opening degree C respectively. The adjusted valve opening degree C = C0*(1 + S), where S ranges from 0.5% to 5%. 3) During the valve adjustment, collect the pressure data of the main supply pipe of the central pipe and the circumferential seam pressure of each bottom lance; perform parabolic fitting on the pressure data of the main supply pipe and the circumferential seam pressure of the bottom lance respectively. The function of the pressure pulse wave j of the main supply pipe changing with time is denoted as The function of the pressure pulse wave j of the circumferential seam changing with time is denoted as 4) Compare the data of the pressure pulse wave of the central tube gas supply main pipe pressure and the annular gap pressure, and calculate the slag hanging effect index through the quantitative evaluation slag hanging effect equation formula (4): wherein and are solved by the following formula (5), and are solved by the following formula (6): Among them, is the pressure of the central pipe gas supply main pipe when the opening of the central pipe gas supply main pipe valve is C0, P iO S is the circumferential seam pressure of the bottom lance i when the opening of the central pipe gas supply main pipe valve is C0; m represents the number of bottom lances at the furnace bottom; n represents the number of pressure pulse waves generated by the regulating valve; i represents the i-th bottom lance; j represents the j-th pressure pulse wave generated by the regulating valve; 5) The exponent E calculated by formula (4) d Judge the slagging effect. If 0.20 < E d ≤ 0.60, it indicates that the slagging effect is good.

2. The recognition method of the slag hanging effect on the bottom of the converter according to claim 1, characterized in that, The following step is also provided between steps 3) and 4): Calculate the effective index based on the extreme points of the pressure pulse wave. The calculation method is as follows in formula (1): In the formula, represents the time corresponding to the extreme value j of the pressure pulse wave of the central pipe gas supply main pipe, and is solved by the following formula (2); represents the time corresponding to the extreme value j of the pressure pulse wave of the i-th circumferential seam of the bottom lance, and is solved by the following formula (3); m represents the number of bottom lances at the furnace bottom; n represents the number of pressure pulse waves generated by the regulating valve; If 0 ≤ E f ≤ 15 s, it is determined to be valid and subsequent steps are carried out.

3. The recognition method of the slag hanging effect on the bottom of the converter according to claim 1, characterized in that: In step 2), the time for adjusting the valve opening degree once is controlled within 4s - 6s, and the adjustment interval time is controlled within 1s - 3s.

4. The method for identifying the slag hanging effect on the bottom of the converter according to claim 1, 2 or 3, characterized in that: In the step 2), the flow rate of the bottom lance central pipe at the original opening C0 is 25 Nm 3 / min to 40 Nm 3 / min.

5. A slag hanging method for a converter, which is identified by using the identification method described in any one of claims 1-4, characterized in that: If 0 < E d ≤ 0.20, then the slag hanging operation is increased by 1 - 2 times; if 0.20 < E d ≤ 0.60, then the smelting of the next heat is carried out; if 0.60 < E d ≤ 1, then the gas supply flow rate of the bottom lance ring gap is reduced by 10% - 15% during the smelting of the next heat.

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