Calculation method and evaluation method for secondary oxidation capacity of stuffing sand to molten steel

Abstract

The invention provides a method for calculating the secondary oxidation capacity of stuffing sand to molten steel. The method comprises the following steps: S1, measuring the content wi of each component i in the stuffing sand; s2, calculating the hot Gibbs free energy change Gi of the reaction between each component i in the stuffing sand and [Al] in the molten steel; s3, the stacking density rho of the stuffing sand is measured, and the weight of the studied object stuffing sand is calculated; s4, calculating the weight WO-i of an oxygen element in a component i capable of reacting with the molten steel in the studied object stuffing sand according to the following calculation formula; and S5, accumulating the weight of all oxygen elements which can react with the molten steel in the studied object stuffing sand to obtain the secondary oxidation capacity Q oxidation of the stuffing sand to the molten steel. The invention further provides a method for evaluating the secondary oxidation capacity of the stuffing sand to the molten steel. According to the calculation method provided by the invention, the secondary oxidation capacity of the stuffing sand to the molten steel can be accurately evaluated, so that a powerful support is provided for selecting reasonable stuffing sand during high-cleanliness steel production.

Description

Technical Field

[0001] This invention relates to the field of metallurgical technology, and in particular to a method for calculating and evaluating the secondary oxidation capacity of diversion sand on molten steel. Background Technology

[0002] Drainage sand is a refractory material used for filling the bottom nozzle of a steel ladle. It is an important metallurgical auxiliary material in the steelmaking process. Specifically, it is filled in the steel flow channel at the bottom of the ladle and plays an important role in guiding the flow when the ladle is opened for pouring.

[0003] Many researchers have conducted extensive studies on guide sand. For example, Chinese Patent CN119187535A discloses a method and ladle baking structure for improving the self-opening rate of ladle nozzles. This includes controlling the installation of nozzle material at the ladle nozzle, ladle rotation, and hot air baking inside the ladle, effectively preventing the guide sand at the nozzle material from sintering and improving the self-opening rate of the ladle nozzle. Chinese Patent CN118893205A discloses a sand-adding device and method for monitoring the ladle sand-adding process. It includes a hoisting system, a sand-adding bucket, and a camera assembly, which can monitor the sand-adding process of the ladle nozzle in real time, promptly detecting whether sand is added normally, whether it is insufficient or misaligned, and whether the sand-adding bucket chain has broken. Chinese Patent CN118580061A discloses a metal-based functionalized guide sand and its preparation method. By optimizing the raw material ratio and preparation process, the guide sand possesses excellent high-temperature resistance, corrosion resistance, and thermal stability, improving the automatic opening rate. Chinese Patent Publication No. CN118559011A discloses a method and device for filling sand into the sliding gate of an tundish, which can greatly reduce operational risks, ensure personnel safety, achieve precise delivery of the guiding sand, and avoid filling failure. Chinese Patent Publication No. CN222221131U discloses a ladle upper gate seat brick that improves the ladle self-opening rate, avoiding slag residue caused by small platforms on the inner wall of the gate, ensuring no guiding sand residue at the gate of a new ladle casting line, and improving the ladle self-opening rate. Chinese Patent Publication No. CN118420357A discloses a high self-opening rate refining guiding sand and its preparation method. This guiding sand has good fluidity, low thermal expansion rate, and appropriate bulk density, and also has the advantages of appropriate sintered layer thickness, strong resistance to penetration and erosion, and can effectively improve the automatic opening rate.

[0004] When the main casting begins, the guide sand enters the tundish of the continuous casting process. Some reactive components in the guide sand (such as SiO2, FeO, etc.) undergo a secondary oxidation reaction with elements such as [Al] in the molten steel in the tundish (2y[Al] + 3M). x O y →yAl2O3+3x[M],M x O y(As a reactive component of the diverting sand), it forms a large amount of Al2O3 inclusions, affecting the cleanliness of molten steel. The aforementioned patents related to diverting sand mainly focus on improving the self-opening rate of diverting sand by optimizing its composition and filling device. However, there is little research on quantitative evaluation and calculation methods for the secondary oxidation capacity of diverting sand on molten steel, and no related patents exist. Summary of the Invention

[0005] The technical problem solved by this invention is to provide a method for calculating the secondary oxidation capacity of molten steel by diverting sand, which can accurately calculate the secondary oxidation capacity of molten steel by diverting sand.

[0006] In view of this, this application provides a method for calculating the secondary oxidation capacity of diversion sand on molten steel, including the following steps:

[0007] S1. Determine the content of each component i in the drainage sand. i ;

[0008] S2. Calculate the thermal Gibbs free energy change ΔG of the reaction between each component i in the diversion sand and [Al] in the molten steel. i When △G i When <0, component i of the guiding sand undergoes a secondary oxidation reaction with the molten steel. The molecular formula of this component is M. x O y M represents the non-oxygen element in component i, and O represents the oxygen element in component i.

[0009] S3. Measure the bulk density ρ of the diversion sand to fill a unit volume of 1m³. 3 Taking the drainage sand required for the steel flow channel as the research object, the weight of the drainage sand is calculated according to the following formula:

[0010] W 砂 =ρ×1;

[0011] S4. Calculate the weight W of oxygen element in component i that can react with molten steel in the guiding sand of the research object according to the following formula. O-i :

[0012]

[0013] In the formula, m O m M These are the relative atomic masses of oxygen and M in component i, respectively.

[0014] S5. Sum the weights of all oxygen elements in the guiding sand that can react with molten steel to obtain the secondary oxidation capacity Q of the guiding sand to molten steel. 氧化 The calculation formula is as follows:

[0015] Q 氧化 =∑W O-i.

[0016] In some specific embodiments, in step S1, the method of measurement is a spectrometer; and or, in step S1, the amount of drainage sand is ≥30g.

[0017] In some specific embodiments, in step S2, the calculated thermal Gibbs free energy change is calculated using the thermodynamic software Factsage, and / or the reaction temperature for calculating the thermal Gibbs free energy change is 1500–1700°C.

[0018] In some specific embodiments, in step S2, when G i When the value is ≥0, the component i of the guiding sand does not undergo a secondary oxidation reaction with the molten steel, and the effect of this component on the secondary oxidation of the molten steel is not considered.

[0019] In some specific embodiments, the method for calculating the bulk density of the diversion sand in step S3 is as follows:

[0020] Weigh the 1000ml standard measuring cup and record the weight as W1 (kg);

[0021] Pour the drainage sand through a funnel to fill the measuring cup, weigh the resulting measuring cup, and record the weight as W2 (kg);

[0022] The bulk density ρ (kg / m³) of the diversion sand is calculated using the following formula. 3 ):

[0023]

[0024] In some specific embodiments, the aperture of the funnel is 3-5 mm.

[0025] In some specific embodiments, the composition of the diversion sand includes one or more of Cr2O3, SiO2, FeO, ZrO2 and Al2O3.

[0026] In some specific embodiments, when △G i When the temperature is <0, the components of the guiding sand, Cr2O3, SiO2, and FeO, undergo a secondary oxidation reaction with the molten steel.

[0027] This application also provides a method for evaluating the secondary oxidation capacity of diversion sand on molten steel, comprising the following steps:

[0028] Calculate the secondary oxidation capacity Q of several diversion sands on molten steel. 氧化 The calculation method for the secondary oxidation capacity of each diversion sand to molten steel shall be carried out in accordance with the calculation method described in the above scheme.

[0029] Comparing several Q 氧化 The value of Q 氧化The higher the value, the greater the degree of secondary oxidation pollution of the molten steel caused by this type of diversion sand.

[0030] In some specific embodiments, the number of the plurality of drainage sands is ≥2.

[0031] This application provides a method for calculating the secondary oxidation capacity of molten steel by guiding sand. First, the content of each component in the guiding sand is determined. Then, the thermal Gibbs free energy change of the reaction between each component in the guiding sand and [Al] in the molten steel is calculated to determine the components in the guiding sand that undergo secondary oxidation with the molten steel. Next, the bulk density of the guiding sand is measured, and the weight of the guiding sand under study is calculated accordingly. Subsequently, the weight of oxygen in the components of the guiding sand that can react with the molten steel is calculated. Finally, the weights of oxygen in all components of the guiding sand that react with the molten steel are summed to obtain the secondary oxidation capacity of the guiding sand for molten steel. The calculation method provided in this application can accurately calculate the secondary oxidation capacity of molten steel by guiding sand.

[0032] This application also provides a method for evaluating the secondary oxidation capacity of diverting sand on molten steel. It uses the above calculation method to calculate the secondary oxidation capacity of different types of diverting sand on molten steel with high accuracy, which can provide a basis for selecting appropriate diverting sand in the production of high-cleanliness steel. Detailed Implementation

[0033] To further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, and not for limiting the scope of the claims of the present invention.

[0034] In view of the impact of existing diversion sand on the cleanliness of molten steel and the requirement for selecting diversion sand for high-cleanliness steel, this application provides a method for calculating the secondary oxidation capacity of diversion sand on molten steel, which can accurately calculate the secondary oxidation capacity of diversion sand on molten steel. This application also provides a method for evaluating the secondary oxidation capacity of diversion sand on molten steel, which can accurately calculate and evaluate the secondary oxidation capacity of different types of diversion sand on molten steel, thereby enabling the selection of suitable diversion sand for high-cleanliness steel production and reducing secondary oxidation pollution of molten steel by diversion sand. Specifically, this invention discloses a method for calculating the secondary oxidation capacity of diversion sand on molten steel, including the following steps:

[0035] S1. Determine the content of each component i in the drainage sand. i ;

[0036] S2. Calculate the thermal Gibbs free energy change ΔG of the reaction between each component i in the diversion sand and [Al] in the molten steel. i When △G i When <0, component i of the guiding sand undergoes a secondary oxidation reaction with the molten steel. The molecular formula of this component is denoted as M. x O yM represents the non-oxygen element in component i, and O represents the oxygen element in component i.

[0037] S3. Measure the bulk density ρ of the diversion sand to fill a unit volume of 1m³. 3 Taking the drainage sand required for the steel flow channel as the research object, the weight of the drainage sand is calculated according to the following formula:

[0038] W 砂 =ρ×1;

[0039] S4. Calculate the weight W of oxygen element in component i that can react with molten steel in the guiding sand of the research object according to the following formula. O-i :

[0040]

[0041] In the formula, m O m M These are the relative atomic masses of oxygen and M in component i, respectively.

[0042] S5. Sum the weights of all oxygen elements in the guiding sand that can react with molten steel to obtain the secondary oxidation capacity Q of the guiding sand to molten steel. 氧化 The calculation formula is as follows:

[0043] Q 氧化 =∑W O-i .

[0044] In the calculation method for the secondary oxidation capacity of molten steel by the guiding sand, in step S1, the content w of each component i in the guiding sand is first determined. i In this process, for the sake of detection accuracy, the content of the drainage sand is ≥30g. In this application, the determination of the content w of each component i in the drainage sand is... i A spectrometer is preferably used, which can directly determine the content of each component in the diverting sand. The diverting sand is a refractory material, generally including one or more of Cr2O3, SiO2, FeO, ZrO2, Al2O3, and MgO. The spectrometer can determine the specific content of these components in the diverting sand. If the diverting sand includes Cr2O3, SiO2, FeO, and Al2O3, then the Cr2O3 content determined by the spectrometer is w. Cr2O3 The SiO2 content is w SiO2 The FeO content is w FeO The content of Al2O3 is w Al2O3 .

[0045] In step S2, the thermal Gibbs free energy change ΔG of the reaction between each component i in the diversion sand and [Al] in the molten steel is calculated. i When △G iWhen <0, component i of the guiding sand undergoes a secondary oxidation reaction with the molten steel. The molecular formula of this component is M. x O y M represents the non-oxygen element in component i, and O represents the oxygen element in the component. In this process, thermodynamic Factsage calculations are preferred, and this method is used to calculate the thermo-Gibberish free energy change ΔG of the reaction between each component in the diversion sand and [Al]. i When △G i When <0, component i of the guiding sand undergoes a secondary oxidation reaction with the molten steel. The molecular formula of this component is M. x O y M represents the non-oxygen element in component i, and O represents the oxygen element in component i. When G i When ≥0, the component i of the guide sand does not undergo secondary oxidation reaction with the molten steel, and its effect on the secondary oxidation of the molten steel is not considered. For example, calculate the thermal Gibbs free energy change ΔG for the reactions of Cr2O3, SiO2, FeO, Al2O3, and [Al] in the guide sand. i Among them, ΔG of Cr2O3, SiO2, and FeO i If all three components are less than zero, then the above three components will undergo a secondary oxidation reaction with the molten steel.

[0046] In step S3, the bulk density ρ of the diversion sand is measured. The bulk density of the diversion sand can be measured according to methods well known to those skilled in the art. The bulk density of the diversion sand is also provided in this application, specifically as follows:

[0047] Weigh the 1000ml standard measuring cup and record the weight as W1 (kg);

[0048] Pour the drainage sand through a funnel to fill the measuring cup, weigh the resulting measuring cup, and record the weight as W2 (kg);

[0049] The bulk density ρ (kg / m³) of the diversion sand is calculated using the following formula. 3 ):

[0050]

[0051] In the above-mentioned process of determining bulk density, for the sake of simplicity, the measuring cup is preferably the 1000ml size mentioned above. Similarly, other sizes of measuring cups can also be selected. To ensure the accuracy of the bulk density of the guiding sand, the guiding sand is preferably poured into the measuring cup through a funnel with a diameter of 5mm until the measuring cup is full and overflowing. Then, a non-magnetic straight ruler is used to level the guiding sand. During this process, the guiding sand is not squeezed. Then, the measuring cup is gently tapped to ensure that the guiding sand is compacted. Finally, the weight W2 (kg) of the measuring cup filled with guiding sand is measured.

[0052] The bulk density ρ (kg / m³) of the diversion sand is calculated using the following formula. 3 ):

[0053]

[0054] In step S3, the weight of the diversion sand was further calculated, specifically based on a filling unit volume of 1m³. 3 Taking the drainage sand required for the steel flow channel as the research object, the weight of the drainage sand is calculated according to the following formula:

[0055] W 砂 =ρ×1;

[0056] In this application, for the sake of simplified calculation, a unit volume of 1m³ is used. 3 The study focuses on the diversion sand required for the steel flow channel. The simplification of this condition does not affect the secondary oxidation capacity of the final diversion sand for molten steel.

[0057] Based on the calculated weight of the diversion sand, according to the above △G i and w i Calculate the weight W of oxygen element in the component i that can react with molten steel in the diversion sand of the above-mentioned research object. O-i The specific calculation formula is as follows:

[0058]

[0059] In the formula, m O m M These are the relative atomic masses of oxygen and M in component i, respectively.

[0060] Based on the above example, the weight of O in Cr2O3, SiO2, and FeO in the diversion sand of the above-mentioned research object is calculated, i.e., W. O-Cr2O3 W O-SiO2 W O-FeO .

[0061] Finally, by summing up the weights of all oxygen elements in the guiding sand that can react with molten steel, the secondary oxidation capacity Q of the guiding sand to molten steel can be determined. 氧化 :

[0062]

[0063] For example, Q 氧化 =W O-Cr2O3 +W O-SiO2 +W O-FeO .

[0064] Furthermore, this application also provides a method for evaluating the secondary oxidation capacity of diversion sand on molten steel, including the following steps:

[0065] Calculate the secondary oxidation capacity Q of several diversion sands on molten steel. 氧化The calculation method for the secondary oxidation capacity of each diversion sand to molten steel shall be carried out in accordance with the calculation method described in the above scheme.

[0066] Comparing several Q 氧化 The value of Q 氧化 The higher the value, the greater the degree of secondary oxidation pollution of the molten steel caused by this type of diversion sand.

[0067] In the above evaluation method, the secondary oxidation capacity Q of multiple types and component ratios of diversion sand on molten steel is calculated according to the above calculation method. 氧化 To obtain different Q values 氧化 For example: Q 氧化1 Q 氧化2 Q 氧化3 Q 氧化4 ·····Q 氧化n Compare the above Q 氧化 The value of Q 氧化 The higher the value, the greater the degree of secondary oxidation pollution of the molten steel caused by this type of guiding sand, which is more detrimental to the control of the cleanliness of the molten steel. Specifically, the number of guiding sands is ≥2, and specifically, the number of guiding sands is 3 to 10.

[0068] This invention provides a method for calculating and evaluating the secondary oxidation capacity of diverting sand on molten steel. It can accurately calculate and evaluate the secondary oxidation capacity of different types of diverting sand on molten steel, thereby providing key data support for selecting appropriate diverting sand during the production of high-cleanliness steel and reducing the secondary oxidation pollution of molten steel by diverting sand. This method can be promoted and applied in the industry.

[0069] To further understand the present invention, the following detailed description of the calculation method for the secondary oxidation capacity of the diversion sand provided by the present invention on molten steel is provided in conjunction with the embodiments. The scope of protection of the present invention is not limited by the following embodiments.

[0070] Example: Evaluation and experimental verification of the secondary oxidation capacity of different types of diversion sand on molten steel

[0071] (1) Take 40g of each of the three types of drainage sand and use a spectrometer to determine the content of each component of the drainage sand. The results are shown in Table 1.

[0072] Table 1. Component Analysis Results of Drainage Sand

[0073]

[0074] (2) The thermodynamic software Factsage was used to calculate the reaction process of each component i of the diverting sand with [Al] in the molten steel in step (1). The thermal Gibbs free energy change ΔG was calculated. i The reaction temperature was calculated to be 1600℃, and the results are shown in Table 2.

[0075] Table 2. Gibbs free energy change of the reaction process between the composition of the guiding sand and the molten steel [Al].

[0076]

[0077] The calculation results in Table 2 show that the ΔG of the reaction between Cr2O3, SiO2, FeO and [Al] is less than 0, indicating that these three components can undergo secondary oxidation reaction with molten steel, and these three components need to be considered when calculating the secondary oxidation capacity of the slurry sand; the ΔG of ZrO2 and Al2O3 is greater than or equal to 0, indicating that these two components in the slurry sand do not undergo secondary oxidation reaction with molten steel, and these three components can be disregarded when calculating the secondary oxidation capacity of the slurry sand.

[0078] (3) Determine the bulk density of the diversion sand:

[0079] (3.1) Take a standard measuring cup with a specification of 1000ml and weigh it W1 (kg) = 0.10kg;

[0080] (3.2) Pour the drainage sand into a funnel with a 5mm aperture, allowing the drainage sand to flow directly into the measuring cup until the measuring cup is full and overflows;

[0081] (3.3) Use a non-magnetic straight ruler to level the drainage sand, but do not squeeze the drainage sand. Then tap the measuring cup lightly to ensure that the drainage sand is compacted, and weigh the measuring cup W2. Then the full cup weights of drainage sand A, B and C are 6.6kg, 6.1kg and 5.8kg respectively (excluding the weight of the measuring cup).

[0082] (3.4) Calculate the bulk density ρ (kg / m³) of the diversion sand. 3 ):

[0083]

[0084] Substituting the measurement results from (3.1) and (3.3) into equation (1), the bulk density of the three types of diversion sand, A, B, and C, can be calculated to be 6600 kg / m³. 3 6100kg / m 3 5800kg / m 3 ;

[0085] (4) Filling unit volume (1m) 3 Taking the diversion sand required for the steel flow channel as the object, calculate the secondary oxidation capacity Q of three types of diversion sand on molten steel. 氧化 :

[0086] (4.1) Calculate the weight (kg) of the diversion sand of the object under study:

[0087] W 砂 =ρ×1 (2);

[0088] Substituting the calculation results of (3.4) into formula (2), the weights of the three types of diversion sand, A, B, and C, can be calculated to be 6600 kg, 6100 kg, and 5800 kg, respectively.

[0089] (4.2) Calculate the amount of molten steel that can react with the molten steel in the guiding sand of the object under study (ΔG). i The weight W of oxygen element contained in component i of <0) Oi :

[0090]

[0091] In the formula, m Oi m Mi These are the relative atomic masses of oxygen and M in component i, respectively.

[0092] From the Gibbs free energy change calculation results in step (2), it can be seen that for the slag A under study, the components that can react with molten steel are Cr2O3, SiO2, and FeO; for the slag B under study, the components that can react with molten steel are SiO2 and FeO; and for the slag C under study, the components that can react with molten steel are SiO2 and FeO. The relative atomic weights of Cr, Si, Fe, and O contained in these components are m Cr =52, m Si =28, m Fe =56, m O =16; Based on the above data, the weight of oxygen in each reaction component of the three types of diversion sand can be calculated:

[0093] For the diversion sand of the research object A,

[0094] The weight of oxygen in its reactive component Cr2O3 is:

[0095]

[0096] The weight of oxygen in its reactive component SiO2:

[0097]

[0098] The weight of oxygen in its reactive component FeO is:

[0099]

[0100] For the diversion sand B under study

[0101] The weight of oxygen in its reactive component SiO2:

[0102]

[0103] The weight of oxygen in its reactive component FeO is:

[0104]

[0105] For the object of study C, the diversion sand,

[0106] The weight of oxygen in its reactive component SiO2:

[0107]

[0108] The weight of oxygen in its reactive component FeO is:

[0109]

[0110] (4.3) By summing up the weights of all oxygen elements in the diversion sand that can react with molten steel, the secondary oxidation capacity Q of the diversion sand on molten steel can be determined. 氧化 :

[0111]

[0112] For A-type diversion sand

[0113]

[0114] For B-type diversion sand

[0115]

[0116] For C-type diversion sand

[0117]

[0118] Comparison of Q values ​​of three types of drainage sand 氧化 It can be seen that the order of the secondary oxidation capacity of the three types of diverting sand to molten steel is A diverting sand > B diverting sand > C diverting sand;

[0119] To verify the accuracy of the above evaluation method, three furnace tests were conducted using a vacuum induction furnace. The test steps for each furnace were as follows:

[0120] (1) 100 kg of industrial pure iron is heated and melted in a vacuum induction furnace and then 0.05 kg of aluminum granules are added;

[0121] (2) Heat the molten steel to 1600℃ and hold for 2 minutes. During the holding process, use a corundum rod to continuously stir the molten pool so that the aluminum particles are fully mixed in the molten steel. Then take one steel sample (before adding sand).

[0122] (3) Add 10ml of guiding sand to the molten steel and use a corundum rod to continuously stir the molten steel so that the guiding sand and the molten steel are fully mixed. During the stirring process, the temperature of the molten pool is always maintained at 1600℃. After stirring for 20 minutes, take a steel sample (after adding sand).

[0123] (4) The composition of the steel samples taken during the test was analyzed, and the results are shown in Table 3.

[0124] Table 3. Data on the composition of the tested steel samples

[0125]

[0126] Table 3 shows that the [Al] burn-off values ​​of the steel samples corresponding to the three types of guiding sand (A, B, and C) are 0.0120%, 0.0050%, and 0.0010%, respectively, indicating that the burn-off order is A sand > B sand > C sand. The [Al] burn-off in the molten steel is caused by the reaction between the reactive components in the added guiding sand and [Al], and the reaction process is 2y[Al] + 3MxOy → yAl2O3 + 3x[M]. Therefore, the [Al] burn-off amount in the molten steel characterizes the secondary oxidation capacity of the guiding sand. The experimentally measured [Al] burn-off order (A sand > B sand > C sand) is completely consistent with the secondary oxidation capacity order of the guiding sand (A sand > B sand > C sand) calculated based on the method provided in this application, proving the reliability and accuracy of the calculation method provided in this application.

[0127] The above description of the embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

[0128] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for calculating the secondary oxidation capacity of diversion sand on molten steel, comprising the following steps: S1. Determine the content of each component i in the drainage sand. i ; S2. Calculate the thermal Gibbs free energy change ΔG of the reaction between each component i in the diversion sand and [Al] in the molten steel. i When △G i When <0, component i of the guiding sand undergoes a secondary oxidation reaction with the molten steel. The molecular formula of this component is M. x O y M represents the non-oxygen element in component i, and O represents the oxygen element in component i. S3. Measure the bulk density ρ of the diversion sand to fill a unit volume of 1m³. 3 Taking the drainage sand required for the steel flow channel as the research object, the weight of the drainage sand is calculated according to the following formula: IN 砂 =ρ×1; S4. Calculate the weight W of oxygen element in component i that can react with molten steel in the guiding sand of the research object according to the following formula. O-i : In the formula, m O m M These are the relative atomic masses of oxygen and M in component i, respectively. S5. Sum the weights of all oxygen elements in the guiding sand that can react with molten steel to obtain the secondary oxidation capacity Q of the guiding sand to molten steel. 氧化 The calculation formula is as follows: Q 氧化 =∑W O-i 。 2. The calculation method according to claim 1, characterized in that, In step S1, the method of measurement is a spectrometer; and or, in step S1, the amount of drainage sand is ≥30g.

3. The calculation method according to claim 1, characterized in that, In step S2, the calculated thermal Gibbs free energy change is calculated using the thermodynamic software Factsage, and / or the reaction temperature for calculating the thermal Gibbs free energy change is 1500–1700 °C.

4. The calculation method according to claim 1 or 3, characterized in that, In step S2, when G i When the value is ≥0, the component i of the guiding sand does not undergo a secondary oxidation reaction with the molten steel, and the effect of this component on the secondary oxidation of the molten steel is not considered.

5. The calculation method according to claim 1, characterized in that, In step S3, the specific method for calculating the bulk density of the diversion sand is as follows: Weigh the 1000ml standard measuring cup and record the weight as W1 (kg); Pour the drainage sand through a funnel to fill the measuring cup, weigh the resulting measuring cup, and record the weight as W2 (kg); The bulk density ρ (kg / m³) of the diversion sand is calculated using the following formula. 3 ):

6. The calculation method according to claim 5, characterized in that, The aperture of the funnel is 3-5 mm.

7. The calculation method according to any one of claims 1 to 6, characterized in that, The components of the diversion sand include one or more of Cr2O3, SiO2, FeO, ZrO2 and Al2O3.

8. The calculation method according to claim 7, characterized in that, When △G i When the temperature is <0, the components of the guiding sand, Cr2O3, SiO2, and FeO, undergo a secondary oxidation reaction with the molten steel.

9. A method for evaluating the secondary oxidation capacity of diverting sand to molten steel, comprising the following steps: Calculate the secondary oxidation capacity Q of several diversion sands on molten steel. 氧化 The calculation method for the secondary oxidation capacity of each diversion sand to molten steel is performed according to the calculation method described in any one of claims 1 to 8. Comparing several Q 氧化 The value of Q 氧化 The higher the value, the greater the degree of secondary oxidation pollution of the molten steel caused by this type of diversion sand.

10. The evaluation method according to claim 9, characterized in that, The number of the aforementioned diversion sands is ≥2.

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