Method for evaluating the cost performance of scrap for a converter

Abstract

The present application relates to a kind of scrap steel cost performance evaluation method for converter: obtain the main chemical components of converter smelting end slag;The metal melting rate and slag forming rate are obtained by carrying out intermediate frequency furnace smelting calculation to the scrap steel to be evaluated;Obtain the mass percentage of silicon dioxide in the slag after intermediate frequency furnace smelting and silicon element in steel;Iron loss due to the formation of slag in the process of converter smelting of the scrap steel to be evaluated is calculated;Calculate effective iron content;According to effective iron content and scrap steel price, calculate unit effective iron price and use it as evaluation index.The present application introduces the concept of effective iron content, on the basis of the metal melting rate and slag forming rate of scrap steel measured by intermediate frequency furnace smelting, further deducts the iron loss required to be taken away by the slag forming amount in the process of converter smelting, calculates the effective iron content of scrap steel, and calculates the unit effective iron price according to the purchase unit price of scrap steel, to guide the procurement department to preferentially purchase the scrap steel variety with lower unit effective iron price, effectively reduces the procurement cost.

Description

Technical Field

[0001] This invention relates to the field of converter smelting technology, and more specifically to a method for evaluating the cost-effectiveness of scrap steel used in converters. Background Technology

[0002] Scrap steel is a commonly used coolant and is widely used in converters due to its economic efficiency. In response to the national "dual carbon" target, steel companies are increasing the proportion of scrap steel in their converters year by year, with many steel companies now exceeding 20% ​​scrap steel, and the cost of purchased scrap steel is constantly increasing.

[0003] To reduce scrap steel costs, cheap shredded scrap steel, steel shavings, and particle steel, known as "economic scrap steel," are gradually entering the procurement lists of steel companies. With the increase in the types of scrap steel, the quality and price of each type vary, and the choice of scrap steel type will directly affect production costs. Therefore, the evaluation of the cost-effectiveness of scrap steel is particularly important.

[0004] Traditionally, scrap steel yield has been used as an evaluation indicator of scrap steel cost-effectiveness. One method is to calculate the yield by feeding scrap steel into a converter for industrial production. This method requires fixing the yield of molten iron and other iron-containing raw materials, resulting in poor accuracy. Furthermore, it is affected by the stability of the converter smelting process, requiring calculations for multiple furnaces, which leads to a long calculation cycle. Another method is to calculate the scrap steel yield using an induction furnace. Although this method has high accuracy in calculating the iron content of scrap steel, it cannot truly reflect the yield of scrap steel during the converter smelting process, especially for low-grade scrap steel with more impurities, where the reliability of cost-effectiveness assessment is poor.

[0005] As converter smelting cost calculation models mature, metallurgists are attempting to use cost models to evaluate the cost-effectiveness of scrap steel. For example, the domestic patent application "A method, apparatus, medium, and electronic equipment for determining the cost-effectiveness of converter scrap steel" (CN120138252 A) obtains the actual scrap steel yield when smelting the target steel grade in the converter for each target scrap steel batching ratio. The cost-effectiveness of scrap steel is determined based on the target scrap steel batching ratio, the actual scrap steel yield, and the scrap steel costs of at least two types of scrap steel. Another domestic patent application, "A multi-dimensional coupled evaluation method for scrap steel used in converter steelmaking" (CN 115759813 A), establishes a scrap steel cost-effectiveness model whose key data include the tax-inclusive price of scrap steel, scrap steel resources, scrap steel yield, tax rate, and total scrap steel cost. The core of these scrap steel cost-effectiveness evaluation methods is the accurate calculation of the scrap steel yield under industrialized converter production.

[0006] The shortcomings of existing technologies are as follows: 1. The method of calculating the yield of scrap steel in industrial production in a converter requires fixing the yield of molten iron and other iron-containing raw materials. The accuracy of the calculation results is poor, and it is affected by the stability of the converter smelting process. Multiple furnaces need to be calculated, and the calculation cycle is long.

[0007] 2. The method of calculating the scrap steel yield by using medium-frequency furnace smelting has high accuracy in calculating the iron content of scrap steel, but it cannot truly reflect the scrap steel yield in the converter smelting process. In particular, the reliability of evaluating the cost-effectiveness of low-grade scrap steel with more impurities is poor.

[0008] 3. Existing cost model evaluation methods rely heavily on accurate calculation of scrap steel recovery rate under converter industrial production, and cannot achieve real-time, efficient and multi-dimensional quantitative evaluation of the cost-effectiveness of scrap steel. Summary of the Invention

[0009] To address the aforementioned problems, this invention provides a method for evaluating the cost-effectiveness of scrap steel used in converters. The aim is to solve the issues of poor accuracy, long calculation cycles, and the inability to quantitatively assess the cost-effectiveness of scrap steel in real time in response to market price fluctuations using traditional methods. This provides a basis for steel companies to adjust their scrap steel procurement strategies in real time based on price fluctuations of various types of scrap steel in the market.

[0010] To solve the above problems, the technical solution provided by the present invention is as follows: A method for evaluating the cost-effectiveness of scrap steel used in converters, characterized by the following steps: S100. Obtain the main chemical composition of the final slag from converter smelting, including the mass percentage of silica and the mass percentage of total iron; S200. Perform medium-frequency furnace smelting calculations on the scrap steel to be evaluated to obtain the metal melting rate and slag formation rate of the scrap steel to be evaluated; obtain the mass percentage of silicon dioxide in the slag and the mass percentage of silicon in the steel after medium-frequency furnace smelting; S300. Based on the mass percentage of silica and the mass percentage of total iron in the slag at the end of the converter smelting, the mass percentage of silica in the slag after medium frequency furnace smelting and the mass percentage of silicon in the steel, calculate the iron loss carried away by the generated slag during the converter smelting process of the scrap steel to be evaluated. S400. Calculate the effective iron content of the scrap steel to be evaluated based on the metal melting rate and the iron loss; S500. Calculate the unit effective iron price of the scrap steel to be evaluated based on the effective iron content and the obtained scrap steel price; S600. The cost-effectiveness of scrap steel is evaluated using the unit effective iron price as an evaluation index, wherein the lower the unit effective iron price, the higher the cost-effectiveness of the scrap steel.

[0011] Preferably, in step S200, the calculation formulas for the metal melting rate and the slag formation rate are as follows: in, Used to characterize the melt flow rate of the metal; Used to characterize the slag formation rate; Used to characterize the quality of metal obtained after melting in an induction furnace; Used to characterize the quality of slag collected after melting in an induction furnace; Used to characterize the quality of scrap steel before smelting in an induction furnace.

[0012] Preferably, in step S300, the formula for calculating the iron loss carried away by the slag generated during the converter smelting process is: in: Used to characterize the mass percentage of silica in the slag after melting in an intermediate frequency furnace; Used to characterize the mass percentage of silicon in the steel after melting in an induction furnace; 2.14 is the molecular weight ratio of SiO2 to Si; The mass percentage of silica used to characterize the final slag of the converter smelting process; The percentage of total iron in the slag at the end of the converter smelting process is used to characterize the total iron content.

[0013] Preferably, in step S400, the formula for calculating the effective iron content is as follows: Wherein: η is used to characterize the effective iron content.

[0014] Preferably, in step S500, the formula for calculating the unit effective iron price is as follows: Wherein: P represents the price of scrap steel; λ represents the price of effective iron per unit.

[0015] Preferably, in step S100, the main chemical components of the converter smelting endpoint slag, in addition to silicon dioxide and iron, also include calcium oxide, magnesium oxide, or manganese oxide.

[0016] Preferably, in step S200, the chemical composition of the steel after melting in the medium frequency furnace includes at least one of carbon, manganese, phosphorus and sulfur, in addition to silicon; the chemical composition of the slag after melting includes at least one of calcium oxide, aluminum oxide, magnesium oxide and manganese oxide, in addition to silicon dioxide.

[0017] Preferably, there are at least two types of scrap steel to be evaluated, or at least two suppliers of the same type of scrap steel, and the cost-effectiveness of scrap steel is evaluated based on the unit effective iron price.

[0018] Preferably, the evaluation method is used on economic scrap steel with an iron content between 80% and 93% and an iron content fluctuation rate greater than 5%.

[0019] Compared with the prior art, the present invention has the following advantages: 1. This invention introduces the concept of "effective iron content". Based on the molten rate and slag formation rate of scrap steel measured by medium frequency furnace smelting, it further deducts the iron loss that needs to be taken away by the amount of slag formed during the converter smelting process to calculate the effective iron content of scrap steel. The effective iron price per unit is calculated based on the purchase price of scrap steel. The effective iron price per unit is used as the evaluation index of the cost performance of scrap steel, thereby realizing a high-precision quantitative evaluation of the cost performance of scrap steel.

[0020] 2. Because this invention can evaluate the cost-effectiveness of scrap steel in real time based on price fluctuations in the scrap steel market, it guides the purchasing department to prioritize the purchase of varieties with higher cost-effectiveness, thereby significantly shortening the long cycle of traditional industrial trials. As a result, based on the calculation that the cost of purchased scrap steel accounts for 10% of the total cost of billet in the converter process, the cost of purchased scrap steel is reduced by 10 yuan per ton, and the cost of producing 1 ton of billet can be reduced by 1 yuan, which has extremely significant economic benefits. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the cost-effectiveness evaluation process for scrap steel used in converters according to a specific embodiment of the present invention; Detailed Implementation

[0022] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. After reading the present invention, any modifications of the present invention in various equivalent forms by those skilled in the art will fall within the scope defined by the appended claims.

[0023] This invention application claims protection for a method for evaluating the cost-effectiveness of scrap steel used in converters, such as... Figure 1 As shown, it includes the following steps: S100. Obtain the main chemical composition of the final slag from converter smelting, including the mass percentage of silicon dioxide and the mass percentage of total iron.

[0024] S200. Perform medium-frequency furnace smelting calculations on the scrap steel to be evaluated to obtain the metal melting rate and slag formation rate of the scrap steel to be evaluated; obtain the mass percentage of silicon dioxide in the slag after medium-frequency furnace smelting and the mass percentage of silicon in the steel.

[0025] S300. Based on the mass percentage of silica and total iron in the slag at the end of converter smelting, the mass percentage of silica in the slag after medium frequency furnace smelting, and the mass percentage of silicon in the steel, calculate the iron loss carried away by the generated slag during the converter smelting process of the scrap steel to be evaluated.

[0026] S400. Calculate the effective iron content of the scrap steel to be evaluated based on the metal melting rate and iron loss.

[0027] S500. Calculate the unit effective iron price of the scrap steel to be evaluated based on the effective iron content and the obtained scrap steel price.

[0028] S600. The cost-effectiveness of scrap steel is evaluated using the unit effective iron price as the evaluation index. The lower the unit effective iron price, the higher the cost-effectiveness of the scrap steel. Based on the expected prices of various types of scrap steel, the unit effective iron price of scrap steel can be compared, and the scrap steel varieties with higher cost-effectiveness can be prioritized for purchase.

[0029] It should be noted that in step S200, the calculation formulas for the metal melting rate and slag formation rate are as follows (1): (1) in, Used to characterize metal melt flow rate; Used to characterize slag formation rate; Used to characterize the quality of metal obtained after melting in an induction furnace; Used to characterize the quality of slag collected after melting in an induction furnace; Used to characterize the quality of scrap steel before smelting in an induction furnace.

[0030] It should be noted that in step S300, the formula for calculating the iron loss carried away by the slag generated during the converter smelting process is as follows (2): (2) in: Used to characterize the mass percentage of silica in the slag after melting in an induction furnace; Used to characterize the mass percentage of silicon in steel after induction furnace melting; 2.14 is the molecular weight ratio of SiO2 to Si; The mass percentage of silica used to characterize the final slag of converter smelting; The percentage of total iron in the slag at the end of converter smelting.

[0031] It should be noted that in step S400, the formula for calculating the effective iron content is as follows (3): (3) Wherein: η is used to characterize the effective iron content.

[0032] It should be noted that in step S500, the specific formula for calculating the unit effective iron price is as follows (4): (4) Where: P is used to characterize the price of scrap steel; λ is used to characterize the price of effective iron per unit.

[0033] It should be noted that, in step S100, the main chemical components of the converter smelting endpoint slag, in addition to silicon dioxide and iron, also include calcium oxide, magnesium oxide, or manganese oxide.

[0034] It should be further explained that, in step S200, the chemical composition of the steel after melting in the medium frequency furnace includes, in addition to silicon, at least one of carbon, manganese, phosphorus and sulfur; the chemical composition of the slag after melting includes, in addition to silicon dioxide, at least one of calcium oxide, aluminum oxide, magnesium oxide and manganese oxide.

[0035] It should be noted that there must be at least two types of scrap steel to be evaluated, or at least two suppliers of the same type of scrap steel. The cost-effectiveness of scrap steel is evaluated based on the unit effective iron price.

[0036] It should be further noted that the evaluation method is used for economic scrap steel with an iron content between 80% and 93% and an iron content fluctuation rate greater than 5%.

[0037] Implementation Case 1: To reduce scrap steel costs, a 120t converter plans to purchase two types of bulk scrap steel as the most economical material. According to the calculation method of this invention, the evaluation steps for the cost-effectiveness of these two types of scrap steel are as follows: Step 1: The average chemical cost of the final slag from a 120t converter smelting process is shown in Table 1 below: Table 1. Chemical composition of final residue Step 2: Purchase a small quantity of Type 2 scrap steel for induction furnace smelting. The calculated metal melting rate and slag formation rate are shown in Table 2 below: Table 2. Metal Melting Rate and Slag Formation Rate The main chemical composition results of the steel ingots and slag after smelting are shown in Table 3 below: Table 3. Main Chemical Composition of Steel Ingots and Slag Step 3: The iron loss carried away by the slag during the converter smelting process of the two types of scrap steel is calculated as shown in Table 4 below: Table 4. Calculation of Iron Loss Taken Away by Slag Formation in Converter Smelting of Scrap Steel Step 4: Calculate the effective iron content of the scrap steel, and calculate the unit effective iron price of the scrap steel based on the purchase price of the scrap steel, as shown in Table 5 below: Table 5. Calculation Table of Unit Effective Iron Price Step 5: Cost-effectiveness analysis of scrap steel: Based on the above calculation results, although the procurement cost of scrap steel #1 is higher than that of scrap steel #2, its effective iron content is higher and the unit effective iron price is lower, making it more cost-effective. Therefore, it is decided to prioritize the procurement of scrap steel #1 and to adjust the procurement strategy in real time according to the fluctuation of scrap steel market prices.

[0038] In the above detailed description, various features are combined together in a single embodiment to simplify this disclosure. This approach to disclosure should not be construed as reflecting an intention that embodiments of the claimed subject matter require more features than are explicitly stated in each claim. Rather, as reflected in the appended claims, the invention is presented with fewer features than all of the features of the single disclosed embodiment. Therefore, the appended claims are hereby explicitly incorporated into the detailed description, wherein each claim stands alone as a preferred embodiment of the invention.

[0039] The disclosed embodiments have been described above to enable any person skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be applied to other embodiments without departing from the spirit and scope of this disclosure. Therefore, this disclosure is not limited to the embodiments given herein, but is consistent with the broadest scope of the principles and novel features disclosed in this application.

[0040] The foregoing description includes examples of one or more embodiments. It is certainly impossible to describe all possible combinations of components or methods in order to describe the above embodiments, but those skilled in the art will recognize that further combinations and arrangements of the various embodiments are possible. Therefore, the embodiments described herein are intended to cover all such changes, modifications, and variations that fall within the scope of the appended claims. Furthermore, the term "comprising" as used in the specification or claims is interpreted in a manner similar to the term "including," as interpreted when used as a conjunction in the claims. Additionally, the use of any term "or" in the specification of the claims is intended to mean "non-exclusive or."

[0041] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for evaluating the cost-effectiveness of scrap steel used in converters, characterized in that: Includes the following steps: S100. Obtain the main chemical composition of the final slag from converter smelting, including the mass percentage of silica and the mass percentage of total iron; S200. Perform medium-frequency furnace smelting calculations on the scrap steel to be evaluated to obtain the metal melting rate and slag formation rate of the scrap steel to be evaluated; obtain the mass percentage of silicon dioxide in the slag and the mass percentage of silicon in the steel after medium-frequency furnace smelting; S300. Based on the mass percentage of silica and the mass percentage of total iron in the slag at the end of the converter smelting, the mass percentage of silica in the slag after medium frequency furnace smelting and the mass percentage of silicon in the steel, calculate the iron loss carried away by the generated slag during the converter smelting process of the scrap steel to be evaluated. S400. Calculate the effective iron content of the scrap steel to be evaluated based on the metal melting rate and the iron loss; S500. Calculate the unit effective iron price of the scrap steel to be evaluated based on the effective iron content and the obtained scrap steel price; S600. The cost-effectiveness of scrap steel is evaluated using the unit effective iron price as an evaluation index, wherein the lower the unit effective iron price, the higher the cost-effectiveness of the scrap steel.

2. The method for evaluating the cost-effectiveness of scrap steel for converters according to claim 1, characterized in that: In step S200, the calculation formulas for the metal melting rate and the slag formation rate are as follows: in, Used to characterize the melt flow rate of the metal; Used to characterize the slag formation rate; Used to characterize the quality of metal obtained after melting in an induction furnace; Used to characterize the quality of slag collected after melting in an induction furnace; Used to characterize the quality of scrap steel before smelting in an induction furnace.

3. The method for evaluating the cost-effectiveness of scrap steel for converters according to claim 1, characterized in that: In step S300, the formula for calculating the iron loss carried away by the slag generated during the converter smelting process is as follows: in: Used to characterize the mass percentage of silica in the slag after melting in an intermediate frequency furnace; Used to characterize the mass percentage of silicon in the steel after melting in an induction furnace; 2.14 is the molecular weight ratio of SiO2 to Si; The mass percentage of silica used to characterize the final slag of the converter smelting process; The percentage of total iron in the slag at the end of the converter smelting process is used to characterize the total iron content.

4. The method for evaluating the cost-effectiveness of scrap steel for converters according to claim 1, characterized in that: In step S400, the formula for calculating the effective iron content is as follows: in: Used to characterize the effective iron content.

5. The method for evaluating the cost-effectiveness of scrap steel for converters according to claim 4, characterized in that: In step S500, the formula for calculating the unit effective iron price is as follows: in: Used to characterize the price of the scrap steel; Used to characterize the effective price of iron per unit.

6. The method for evaluating the cost-effectiveness of scrap steel for converters according to claim 1, characterized in that: In step S100, the main chemical components of the converter smelting endpoint slag, in addition to silicon dioxide and iron, also include calcium oxide, magnesium oxide, or manganese oxide.

7. The method for evaluating the cost-effectiveness of scrap steel for converters according to claim 6, characterized in that: In step S200, the chemical composition of the steel after melting in the medium frequency furnace includes at least one of carbon, manganese, phosphorus and sulfur, in addition to silicon; the chemical composition of the slag after melting includes at least one of calcium oxide, aluminum oxide, magnesium oxide and manganese oxide, in addition to silicon dioxide.

8. The method for evaluating the cost-effectiveness of scrap steel for converters according to claim 1, characterized in that: The scrap steel to be evaluated consists of at least two types, or at least two suppliers of the same type of scrap steel. The cost-effectiveness of the scrap steel is evaluated based on the effective iron price per unit.

9. The method for evaluating the cost-effectiveness of scrap steel for converters according to claim 8, characterized in that: The evaluation method described above is applied to economic scrap steel with an iron content between 80% and 93% and an iron content fluctuation rate greater than 5%.

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