Method for calculating comprehensive cost performance of iron ore powder

Abstract

The invention belongs to the technical field of ironmaking, and provides a method for calculating the comprehensive cost performance of iron ore powder. The method comprises the following steps: firstly, calculating a dry basis non-tax price of iron ore powder to a plant, and then setting a target function and constraint conditions based on an ore matching target of the iron and steel plant; next, selecting a recently common ore blending scheme as basic ore powder, calculating the ore blending scheme by using the target ore powder and the basic ore powder, and calculating a target function value; under the condition that the ratio of the target mineral powder is 0, the lowest ratio of other mineral powder is taken as the lower limit of the ore blending ratio of the mineral powder. And finally, calculating a cost performance index, and sorting the mineral powder according to the size of the index. According to the method, the cost performance of the iron ore powder can be evaluated more comprehensively, the accuracy of purchase decision making is improved, the molten iron cost is reduced, and the market competitiveness of enterprises is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of ironmaking and relates to a method for calculating the comprehensive cost performance of iron ore powder. Background Art

[0002] Blast furnace ironmaking is the core link in the steel production process. Among its cost structure, the cost of iron ore powder accounts for a significant proportion, about 70%. Therefore, reducing the cost of molten iron, especially the cost of iron ore powder, is of great significance to the production cost control of steel enterprises.

[0003] At present, my country's steel enterprises generally use imported ore with a small amount of domestic ore, with a wide variety of iron ore powders and frequent changes in procurement and production. In this context, it is particularly important to establish an effective cost-effectiveness evaluation mechanism for iron ore powders, which not only helps to reduce the procurement cost of iron ore powders, but also improves the efficiency of steel enterprises in controlling production costs.

[0004] The existing methods for calculating the cost-effectiveness of iron ore powder mainly include the ton-iron benefit method, metallurgical value evaluation method, single-burning method, comprehensive grade evaluation method, etc. These methods evaluate the cost-effectiveness of iron ore powder from the aspects of its composition and price, and have certain practicality. However, when calculating the cost-effectiveness, these methods often only consider the composition and price of the ore powder itself, while ignoring the proportion restrictions of the ore powder in actual production. This may result in some ore powders with better cost-effectiveness having lower proportions in actual production due to the limitations of their composition or performance, which in turn affects the company's inventory and capital turnover.

[0005] In addition, some cost-effectiveness calculation methods for iron ore fines only consider the ore blending stage, and fail to fully consider the impact of ore fines on sintering / pelletizing and even blast furnace production costs. This results in the cost-effectiveness evaluation of iron ore fines failing to fully reflect its actual value in the entire production process, limiting the potential of enterprises in reducing costs before iron production. Summary of the invention

[0006] In view of this, the present invention aims to provide a method for calculating the comprehensive cost-effectiveness of iron ore powder, which can more comprehensively evaluate the cost-effectiveness of iron ore powder and provide more accurate procurement and production decision support for steel companies.

[0007] In order to achieve the above object, the present invention provides the following technical solutions:

[0008] A method for calculating the comprehensive cost performance of iron ore powder comprises the following steps:

[0009] Calculate the dry basis ex-factory price of iron ore fines excluding tax;

[0010] Based on the ore allocation target of the steel plant, set the objective function and constraints;

[0011] Select a set of ore blending schemes that must meet the set objective function and constraints, and use the ore powder in the ore blending scheme as the basic ore powder for cost-performance calculation;

[0012] A target ore powder for which cost performance calculation is required is used together with the basic ore powder as ore sources one by one, and an ore blending scheme is calculated according to the aforementioned objective function and constraint conditions. The proportion of the target ore powder in this ore blending scheme is m, and the objective function value calculated by the ore blending scheme is P;

[0013] If the proportion of the ore powder for which the cost performance needs to be calculated is 0 in the ore blending scheme calculation, the lowest proportion of other ore powders in the ore blending calculation is set as the ore blending lower limit m, and the corresponding objective function value P under this proportion is calculated;

[0014] Calculate the cost performance index. The cost performance index calculation formula is: E = P / m. The smaller the cost performance index E is, the higher the cost performance of the mineral powder for the factory's production.

[0015] Repeat the above steps to calculate the cost-effectiveness index of other mineral powders and arrange them in order from small to large. The higher the ranking, the higher the cost-effectiveness ranking of the mineral powder.

[0016] Optionally, the dry basis ex-factory tax-exclusive price of iron ore fines is calculated as:

[0017] Where P 干税 The dry basis price of iron ore powder is excluding tax. 湿 is the wet basis price of iron ore powder, M is the moisture content of ore powder, σ is the tax rate, P 港 is the wet-based port fee, P 国运 is the domestic freight on a wet basis, σ 运 Tax deducted for freight, P 厂内 For wet-based in-plant freight, r 贴息 is the interest rate, P 付款方式 Fees incurred for different payment methods.

[0018] Optionally, ore blending objectives include: lowest blending ore price, lowest sintered ore price, lowest molten iron cost, lowest CO2 emissions from pre-iron processes, and highest molten iron output.

[0019] Optionally, the objective function needs to be extracted from the ore allocation objectives, either from a single objective or from multiple objectives coupled together.

[0020] Optionally, the constraints include one or more of the following: mixed powder composition constraints, mixed powder particle size constraints, sintered ore / pellet composition constraints, sintered ore / pellet cold strength constraints, sintered ore / pellet metallurgical property constraints, and blast furnace molten iron and slag composition constraints.

[0021] Optionally, the basic ore powder needs to be selected from the ore blending scheme commonly used by the plant in the recent period, and the ore blending scheme must meet all the above constraints.

[0022] Optionally, when solving the ore allocation scheme, a simple linear programming mathematical model is constructed to solve it.

[0023] Optionally, when solving the ore allocation scheme, a multivariate nonlinear mathematical model is constructed according to the complexity of the ore allocation objectives and constraint conditions, and the solution is performed based on a genetic algorithm.

[0024] The beneficial effects of the present invention are:

[0025] Comprehensively reflect the cost-effectiveness ranking of iron ore powder: The method of the present invention comprehensively reflects the cost-effectiveness ranking of iron ore powder by calculating the cost-effectiveness index of iron ore powder. The calculation of the cost-effectiveness index not only takes into account the composition and price of the ore powder itself, but also includes the maximum proportion of the ore powder in the ore blending calculation, making the cost-effectiveness ranking of iron ore powder more accurate and comprehensive.

[0026] Avoiding the situation of limited proportions: The method of the present invention can effectively avoid the situation where some mineral powders are ignored in the ore blending due to their price advantage, thereby resulting in low proportions in the steel plant and affecting the inventory and capital turnover in the plant.

[0027] Improve the accuracy of iron ore powder purchasing decisions: Since the present invention takes into account the impact of ore powder on sintering / pelletizing and blast furnace production costs, the obtained iron ore powder cost-effectiveness ranking not only represents the advantages and disadvantages of the ore powder itself, but also reflects its actual value in the entire production process, providing more accurate support for iron ore powder purchasing decisions.

[0028] Reducing molten iron costs: The method of the present invention helps steel companies to more effectively evaluate and select iron ore powder, thereby reducing procurement costs and production costs and improving the market competitiveness of the company.

[0029] Improve production efficiency and cost control: By constructing a mathematical model and solving a genetic algorithm, the present invention improves the efficiency and practicality of calculating the cost performance of iron ore powder, helps steel companies to quickly and accurately evaluate the cost performance of iron ore powder, and provides powerful decision-making support for iron ore powder procurement and ironmaking production.

[0030] Other advantages, objectives and features of the present invention will be described in the following description to some extent, and to some extent, will be obvious to those skilled in the art based on the following examination and study, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be described in detail below in conjunction with the accompanying drawings, wherein:

[0032] Figure 1 The figure is a flow chart of an implementation form of the present invention. DETAILED DESCRIPTION

[0033] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments only illustrate the basic concept of the present invention in a schematic manner, and the following embodiments and features in the embodiments can be combined with each other without conflict.

[0034] Among them, the drawings are only used for illustrative explanations, and they only represent schematic diagrams rather than actual pictures, and should not be understood as limitations on the present invention. In order to better illustrate the embodiments of the present invention, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of actual products. For those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0035] The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if the terms "upper", "lower", "left", "right", "front", "rear", etc. indicate the orientation or position relationship, they are based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the terms describing the position relationship in the drawings are only used for illustrative purposes and cannot be understood as limiting the present invention. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0036] See also Figure 1 , which is a calculation process of this embodiment. The comprehensive cost performance of mineral powder is calculated according to this calculation process. The specific process is as follows:

[0037] 1) First, the composition and wet basis price of iron ore powder are obtained, as shown in Table 1. The external logistics cost, in-plant logistics cost, tax rate and other parameters of the iron ore powder of the factory are obtained, as shown in Table 2. The dry basis to factory tax-exclusive price of each ore powder is calculated according to the dry basis to factory tax-exclusive price formula, as shown in Table 1.

[0038] Table 1 Iron ore powder composition and wet basis price

[0039]

[0040] Table 2 Iron ore powder tax rate, in-plant transportation and other prices

[0041] parameter σ <![CDATA[P 港 ]]> <![CDATA[P 国运 ]]> <![CDATA[σ 运 ]]> <![CDATA[P 厂内 ]]> <![CDATA[r 贴息 ]]> <![CDATA[P 付款方式 ]]> Numeric 13％ 15 yuan / t 30 yuan / t 10％ 10 yuan / t 0.5％ 3 yuan / t

[0042] 2) Objective function setting: In this implementation, the objective function of the optimal ironmaking cost, which is coupled with the lowest molten iron cost, the maximum molten iron output, and the lowest energy consumption and carbon emissions, is shown in formula (1):

[0043]

[0044] Where: P is the optimal cost per ton of iron, yuan / T; M coke is the coke ratio corresponding to a certain ore blending scheme, kg / t; M i is the iron consumption per ton of the i-th raw material under a certain ore allocation scheme; P i is the material price, RMB / T; Y0 is the corresponding molten iron output under a certain ore allocation scheme, t; η Y is the influence coefficient between the furnace grade and output, t / 1%; △T Fe It is the difference between the corresponding furnace grade under a certain ore blending plan and the furnace grade under the benchmark plan; C0 is the cost of pulverized coal injection per ton of iron and other water, electricity, wind and gas manufacturing costs under the benchmark plan; C1 is fixed costs such as depreciation.

[0045] 3) Constraint setting:

[0046] ① Constraints on the proportion of furnace materials

[0047]

[0048] XL i ≤x i ≤XH i (3)

[0049] Where: X i is the ratio of blast furnace raw materials in the scheme, %; XL i is the lower limit of the i-th raw material; XH i is the upper limit of the input of the i-th raw material.

[0050] ②Amount of molten iron

[0051]

[0052] Where: X is the raw material ratio, kg; TFe is the total iron mass fraction, %; [Fe] is the iron content of molten iron, %; η Fe is the distribution rate of iron, %; M and J are the amount of coal powder and coke, kg; subscript S is sintered ore; P is pelletized ore; L is lump ore; F is flux; M is coal powder; J is coke.

[0053] ③ Slag conditions

[0054] The constraints on slag conditions mainly include the basicity of the slag, the magnesium-aluminum ratio, the slag ratio, and the composition.

[0055] The CaO content of the slag is:

[0056] CaO slag =X S CaO S +X P1 CaO P1 +X P2 CaO P2 +X L1 CaO L1 +X L2 CaO L2 +X F CaO F +MCaO M +JCaO J (5)

[0057] The amount of SiO2 in the slag is:

[0058] SiO 2slag =X S SiO 2S +X P1 SiO 2P1 +X P2 SiO 2P2 +X L1 SiO 2L1 +X L2 SiO 2L2 +X F SiO 2F +MSiO 2M +JSiO 2J -(SiO2) r (6)

[0059] The constraint on slag basicity is:

[0060]

[0061] Where: R d and R u are the lower and upper limits of slag basicity respectively.

[0062] The amount of MgO in the slag is:

[0063] MgO slag =X S MgO S +X P1 MgO P1 +X P2 MgOP2 +X L1 MgO L1 +X L2 MgO L2 +X F MgO F +MMgO M +JMgO J (8)

[0064] The amount of Al2O3 in the slag is:

[0065] Al2O 3slag =X S Al2O 3S +X P1 Al2O 3P1 +X P2 Al2O 3P2 +X L1 Al2O 3L1 +X L2 Al2O 3L2 +X F Al2O 3F +MAl2O 3M +JAl2O 3J (9)

[0066] The constraint of slag magnesium-aluminum ratio is:

[0067]

[0068] Where: MA d and MA u They are the lower and upper limits of the slag magnesium-aluminum ratio respectively.

[0069] The amount of SiO2 consumed by reduction is:

[0070]

[0071] Where: [Si] is the silicon content in molten iron.

[0072] In blast furnace ironmaking, the coke ratio, furnace grade, ore powder type, etc. all have a certain influence on the blast furnace slag ratio. These conditions will affect the smooth operation of the blast furnace and the quality of pig iron.

[0073] The constraint on the slag volume is:

[0074] Q d ≤CaO slag +SiO 2slag +MgO slag +Al2O 3slag +FeO slag +MnO slag +S slag / 2≤Qu (12)

[0075] Where: Q d and Q u are the lower and upper limits of the slag amount respectively.

[0076] ④ Molten iron quality

[0077] In addition to the molten iron temperature and molten iron [Si] meeting certain production requirements, qualified molten iron also needs to control the impurity content in the molten iron. For example, excessive content of [S], [P], etc. will also make the molten iron quality unqualified, so the molten iron quality needs to be controlled.

[0078] Min [Si] ≤[Si]≤Max [Si] (13)

[0079] [P]≤Max [P] (14)

[0080] [S]≤Max [S] (15)

[0081] Where: [Si], [S], [P] are the contents of Si, S, and P in molten iron, Min [Si] , Max [Si] , Max [P] , Max [S] They are the upper and lower limits of Si content, and the upper limits of S content and P content respectively.

[0082] 4) Determination of basic ore powder types: Select several sets of ore blending schemes used recently by the plant, and calculate the ore blending scheme that meets the above constraints as shown in Table 3. Solve the corresponding ore blending cost, sintering ore cost and ironmaking cost as shown in Table 3, and use this as the benchmark scheme to set constraints. According to the ore blending scheme, in this ore powder cost performance calculation, Newman powder, steel powder, Mike powder and Ka powder are selected as the basic ore powders for ore blending.

[0083] Table 3 Basic ore powder ratio and molten iron cost calculation under this ratio

[0084]

[0085]

[0086] 5) Mineral powder proportion, corresponding objective function and price ratio index calculation: According to the above objective function and constraints, a mathematical model is constructed. The target mineral powders for which the cost performance needs to be calculated are taken as ore sources one by one together with the basic mineral powder, and the mineral proportion calculation is performed to obtain the maximum proportion m of the mineral powder, and the objective function p under the mineral proportion scheme is calculated. For the case where the mineral powder for which the cost performance needs to be calculated has a proportion of 0 in the mineral proportion scheme calculation, such as PB powder and SP10 powder in the table, the lowest proportion of other mineral powders in the mineral proportion calculation (the lowest proportion in this calculation is Indian powder 57, and the lowest proportion is 1.2%) is used, and 1.2% is used as the mineral proportion lower limit, the mineral proportion scheme is calculated, and the corresponding objective function value P under this proportion is calculated. The results are shown in Table 4.

[0087] Table 4 Maximum proportion of each single mineral powder, corresponding objective function and cost performance index

[0088] Serial number Iron ore powder Dry basis ex-factory price excluding tax (yuan / t) Maximum ratio m / % Objective function value P Cost-effectiveness index Ranking 1 PB powder 944.09 1.2 2856.3 2380.3 22 2 Super Special 800.26 14.9 2838.7 190.5 8 3 Campbell powder 848.80 5.9 2847.3 482.6 11 4 SP10 870.28 1.2 2853.4 2377.8 17 5 One piece powder 691.92 15.1 2849.2 188.7 7 6 Mike powder 915.72 40.0 2849.2 71.2 2 7 Roy Hill 924.91 1.2 2853.1 2377.6 15 8 Newman powder 950.90 15.1 2849.2 188.7 7 9 Kim Bubba Powder 901.58 1.2 2853.2 2377.7 16 10 Card powder 1016.18 29.8 2849.2 95.6 3 11 Printing powder 57 716.08 1.2 2849.7 2374.8 14 12 Yangdi powder (small) 876.01 1.2 2854.8 2379.0 21 13 MB powder 880.95 1.2 2853.8 2378.2 19 14 Mixed powder 890.49 1.2 2854.2 2378.5 20 15 IOH4 771.64 1.2 2853.7 2378.1 18 16 Mine-Low Grade 886.48 1.4 2850.8 2036.3 13 17 BRBF 929.73 16.6 2850.9 171.7 5 18 RTGF 903.44 40.0 2844.3 71.1 1 19 Sierra Leone Powder 880.03 9.2 2856.2 310.5 9 20 Russian fine powder 1010.16 6.1 2854.1 467.9 10 21 IOC6 907.54 4.7 2858.1 608.1 12 22 Venezuelan powder 1030.67 19.7 2856.7 145.0 4 23 Pu Ming fine powder 1016.29 1.2 2859.2 2382.7 24 24 Chilean Flour 1075.38 1.2 2857.7 2381.4 23

[0089] 6) Calculation of the cost performance index of mineral powder: According to the maximum ratio m of a single mineral powder and the objective function P under this ratio, the cost performance index of this mineral powder is calculated, and the cost performance index is sorted from small to large. The results are shown in Table 4. From the cost performance calculation results, the top three mineral powders in terms of cost performance are: RTGF, Mike powder and Ka powder.

[0090] 7) Verification of cost-effectiveness calculation results: The above calculation results show that the cost-effectiveness of RTGF ranks first, higher than several basic ore powders. Therefore, the RTGF ore powder with higher cost-effectiveness is included in the ore source of ore blending, and the ore blending calculation is optimized. The optimized ore blending scheme, sintered ore cost, and molten iron cost are shown in Table 5. It can be seen from the table that after the RTGF ore powder with high cost-effectiveness is added, compared with the data in Table 3 without RTGF ore powder, the ore blending cost is reduced by 16.2 yuan / t, the sintered ore cost is reduced by 14.5 yuan / t, and the molten iron cost is reduced by 6 yuan / t. Therefore, it is verified that this cost-effectiveness calculation model has a certain effect on reducing the cost of molten iron.

[0091] Table 5 Optimized ore distribution plan

[0092]

[0093] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution, which should be included in the scope of the claims of the present invention.

Claims

1. A method for calculating the comprehensive cost performance of iron ore powder, characterized in that: The following steps are involved: Calculate the dry basis ex-factory price of iron ore fines excluding tax; Based on the ore allocation target of the steel plant, set the objective function and constraints; Select a set of ore blending schemes that must meet the set objective function and constraints, and use the ore powder in the ore blending scheme as the basic ore powder for cost-performance calculation; A target ore powder for which cost performance calculation is required is used together with the basic ore powder as ore sources one by one, and an ore blending scheme is calculated according to the aforementioned objective function and constraint conditions. The proportion of the target ore powder in this ore blending scheme is m, and the objective function value calculated by the ore blending scheme is P; If the proportion of the ore powder for which the cost performance needs to be calculated is 0 in the ore blending scheme calculation, the lowest proportion of other ore powders in the ore blending calculation is set as the ore blending lower limit m, and the corresponding objective function value P under this proportion is calculated; Calculate the cost performance index. The cost performance index calculation formula is: E = P / m. The smaller the cost performance index E is, the higher the cost performance of the mineral powder for the factory's production. Repeat the above steps to calculate the cost-effectiveness index of other mineral powders and arrange them in order from small to large. The higher the ranking, the higher the cost-effectiveness ranking of the mineral powder.

2. The method for calculating the comprehensive cost performance of iron ore powder according to claim 1, characterized in that: The calculation formula for the dry basis ex-factory tax-free price of iron ore fines is: 干税 The dry basis price of iron ore powder is excluding tax. 湿 is the wet basis price of iron ore powder, M is the moisture content of ore powder, σ is the tax rate, P 港 is the wet-based port fee, P 国运 is the domestic freight on a wet basis, σ 运 Tax deducted for freight, P 厂内 For wet-based in-plant freight, r 贴息 is the interest rate, P 付款方式 Fees incurred for different payment methods.

3. The method for calculating the comprehensive cost performance of iron ore powder according to claim 1, characterized in that: The ore blending objectives include: lowest ore blending price, lowest sintered ore price, lowest molten iron cost, lowest CO2 emissions from pre-iron processes, and highest molten iron output.

4. The method for calculating the comprehensive cost performance of iron ore powder according to claim 3, characterized in that: The objective function needs to be extracted from the ore matching target, either from a single target or from multiple target coupling.

5. The method for calculating the comprehensive cost performance of iron ore powder according to claim 1, characterized in that: The constraints include one or more of the following: mixed powder composition constraints, mixed powder particle size constraints, sintered ore / pellet composition constraints, sintered ore / pellet cold strength constraints, sintered ore / pellet metallurgical property constraints, and blast furnace molten iron and slag composition constraints.

6. The method for calculating the comprehensive cost performance of iron ore powder according to claim 1, characterized in that: The basic ore powder needs to be selected from the ore blending plan commonly used by the factory in recent times, and the ore blending plan must meet all the above constraints.

7. The method for calculating the comprehensive cost performance of iron ore powder according to claim 1, characterized in that: When solving the ore allocation scheme, a simple linear programming mathematical model is constructed to solve it.

8. The method for calculating the comprehensive cost performance of iron ore powder according to claim 1, characterized in that: When solving the ore allocation scheme, a multivariate nonlinear mathematical model is constructed according to the complexity of the ore allocation target and the constraint condition setting, and the solution is performed based on a genetic algorithm.

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