A multi-dimensional evaluation method for the quality of lime used in steelmaking and its addition and use

Abstract

The present invention specifically relates to a multi-dimensional evaluation of the quality of lime for steelmaking and a method for adding and using the lime. Six indicator data values ​​of lime (CaO content, SiO2 content, S content, ignition loss, activity, and particle size) are obtained from the inspection and testing index library, and the influence values ​​of the above six indicators on the effective oxide content are given. A 4-index stability coefficient W is proposed, and its influence value on the effective oxide content of lime is given as 0.15-0.2, and the effective oxide content of lime 5 is calculated. The adjusted price of lime is calculated according to the constraints (the content of the index agreed in the contract and the change of the price gradient), and the effective oxide tonnage value of lime 8 is calculated with the effective oxide of lime. The method has a clear mechanism, clear logic, and strong applicability. The concept of effective oxide of lime is proposed, which changes the shortcomings of the previous method of evaluating the quality of lime only by the effective CaO content.

Description

Technical Field

[0001] The present invention specifically relates to a multi-dimensional evaluation method of the quality of lime used in steelmaking and a method for adding and using lime. Background Art

[0002] During the steelmaking converter smelting, auxiliary materials need to be added for slag making to remove harmful elements in the molten steel. Lime is the main slag making material for the alkaline steelmaking method. It is calcined from limestone and has a strong dephosphorization and desulfurization capacity. Generally, lime is required to have a high CaO content and as low SiO2 and sulfur content as possible. When the final slag basicity is 3.0, the SiO2 content in the lime increases by 1%, and the effective CaO content will decrease by about 3%. At the same time, the furnace smelting requires less lime and more auxiliary materials such as limestone.

[0003] At present, the main testing indicators of lime in the market are CaO content, SiO2 content, sulfur content, activity and other indicators. The evaluation method is the effective CaO content of lime, effective CaO% = lime CaO% - R × lime SiO2%, R is the slag basicity. This method only considers the influence of CaO content and SiO2 content, and does not consider the influence of other indicators, such as sulfur content, activity, particle size and other factors, and does not include the price dimension. Therefore, only the effective CaO content is considered, and there are factors missing and a single dimension. The quality of lime cannot be comprehensively and effectively evaluated. Therefore, it is impossible to make operational guidance for converter smelting according to the quality of lime, and it is impossible to provide accurate methods for adding lime, which is not conducive to the stable smelting of steelmaking converters, increases the consumption of auxiliary materials, and affects the quality of molten steel. Summary of the invention

[0004] The present invention analyzes and studies such problems with the help of on-site practical work experience, and designs a multi-dimensional evaluation method of the quality of lime for steelmaking and its addition and use. The method consists of: lime inspection index library (CaO content, SiO2 content, sulfur content, ignition loss, activity, particle size), mechanism model library, constraint conditions, stability coefficient, lime effective oxide content, lime effective oxide ton value, and lime furnace addition and use method.

[0005] In order to achieve the above-mentioned invention object, the present invention adopts the following technical solutions:

[0006] A multi-dimensional evaluation method for the quality of lime used in steelmaking comprises the following steps:

[0007] 1) Obtain the data values ​​of six indicators of lime from the inspection and testing indicator library: CaO content, SiO2 content, sulfur content, loss on ignition, activity, and particle size qualification rate;

[0008] 2) According to the formula, calculate the impact values ​​of the six indicators respectively;

[0009] 3. Calculate the effective oxide content of lime according to the influence values ​​of the six indicators obtained in step 2), where effective oxide content of lime = influence value of effective CaO% content + influence value of sulfur content + influence value of loss on ignition + influence value of activity + influence value of particle size + influence value of stability coefficient W;

[0010] 4) Based on the constraints: index content and price gradient changes, calculate the adjusted price of lime;

[0011] 5) According to the value of effective oxide tonnage of lime = adjusted price of lime / effective oxide content of lime, the value of effective oxide tonnage of lime is obtained;

[0012] The lower the effective oxide ton value of lime, the higher the cost performance of lime quality.

[0013] In the above technical solution, further, the formula in step 2) is:

[0014] Effective CaO% content influence value = lime CaO% - R × lime SiO2%, R is slag basicity;

[0015] Sulfur content impact value = sulfur content * 0.2;

[0016] Impact value of loss on burning = (loss on burning - 5) * 17 / 20;

[0017] Activity impact value = (activity - 300) * 10 / 30;

[0018] Particle size impact value = (particle size qualified rate - 90%) * 0.1;

[0019] In the above technical solution, further, in the step 3), the influence value of the stability coefficient W is 0.15-0.2.

[0020] In the above technical solution, further, the constraint conditions in step 4) are as follows:

[0021] CaO content is between 88% and 100%. Taking 88% as the base amount, the price increases by 0.8 yuan / ton for every 0.1% increase.

[0022] The CaO content is between 85% and 88%. Taking 88% as the base amount, the price will be reduced by 1 yuan / ton for every 0.1% reduction.

[0023] The CaO content is between 80% and 85%, with 88% as the base amount. The price will be reduced by 5 yuan / ton for every 0.1% reduction.

[0024] The CaO content is 75%-80%, and the price is 50 yuan / ton;

[0025] The SiO2 content is based on 2.5%, and the price decreases by 1 yuan / ton for every 0.1% increase;

[0026] The sulfur content is based on 0.05%, and the price will decrease by 1 yuan / ton for every 0.01% increase;

[0027] The burning loss is based on 5% as the base amount, and the price will be reduced by 0.5 yuan / ton for every 0.1% increase;

[0028] The active content is 300-350ml, with 350ml as the base amount, the price will be reduced by 1 yuan / ton for every 1ml reduction;

[0029] The active content is between 250-300ml, with 350ml as the base amount, the price will be reduced by 2 yuan / ton for every 1ml reduction;

[0030] The active content is between 200-250ml, with 350ml as the base amount, and the price will be reduced by 3 yuan / ton for every 1ml reduction;

[0031] The particle size of the lime is based on 20-50 mm. The lime with a particle size less than 20 mm and / or a particle size greater than 50 mm and whose weight exceeds 5% of the total weight of the lime is deducted for settlement.

[0032] In the above technical solution, further, the R value is 2.6-3.0.

[0033] The invention provides a method for adding and using white lime, which comprises the following steps: adding the white lime in 2-4 batches, adding the first batch of white lime within 1-3 minutes of blowing, and the amount of the first batch of white lime is 1 / 2 of the total amount of the white lime added; then adding 1 / 4-1 / 2 of the total amount of the white lime each time, and adding the remaining 1 / 2 of the total amount of the white lime within 4-6 minutes.

[0034] Furthermore, the total amount of lime added is as follows: when the effective oxide content of lime is ≥110%, the amount of lime added is 43kg / ton of steel; when the effective oxide content of lime is 100-109%, the amount of lime added is 47kg / ton of steel; when the effective oxide content of lime is 90-100%, the amount of lime added is 53kg / ton of steel.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] 1. This method has a clear mechanism, clear logic and strong applicability. It proposes the concept of effective oxides in lime, which changes the shortcomings of the previous method of evaluating lime quality only by effective CaO content. It evaluates the influence of different index components on the effective oxides in lime, and calculates the ton value of effective oxides by coupling component data, contract standards, price gradient changes and effective matter content in lime. It makes a comprehensive and accurate evaluation of lime quality, and formulates the rules for the use and addition of lime under different smelting conditions of the converter according to the quality situation, including the amount and time of lime addition.

[0037] 2. After using this method, the quality value of lime can be evaluated according to its fluctuation, the lime fluctuation can be dynamically mastered, and an optimization plan for lime addition can be formed to reduce the impact on steelmaking converter smelting. The slag volume can be reduced by 15kg / t, the quality of molten steel can be significantly improved, and the qualified rate of molten steel can be increased by more than 20%. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 Flow chart of the multi-dimensional evaluation method for lime quality. DETAILED DESCRIPTION

[0039] The processing technology of the present invention is further described below in conjunction with specific embodiments.

[0040] Example 1

[0041] A multi-dimensional evaluation method for the quality of lime used in steelmaking comprises the following steps:

[0042] 1) Obtain the data values ​​of six indicators of lime from the inspection and testing indicator library: CaO content, SiO2 content, sulfur content, loss on ignition, activity, and particle size qualification rate;

[0043] 2) According to the formula: effective CaO% content impact value = lime CaO% - R × lime SiO2%, R is slag basicity; R value is 2.6-3.0;

[0044] Sulfur content impact value = sulfur content * 0.2;

[0045] Impact value of loss on burning = (loss on burning - 5) * 17 / 20;

[0046] Activity impact value = (activity - 300) * 10 / 30;

[0047] Particle size impact value = (particle size qualified rate - 90%) * 0.1;

[0048] Calculate the impact values ​​of the six indicators respectively;

[0049] 3) Calculate the effective oxide content of lime according to the influence values ​​of the six indicators obtained in step 2), where the effective oxide content of lime = the influence value of effective CaO% content + the influence value of sulfur content + the influence value of loss on ignition + the influence value of activity + the influence value of particle size + the influence value of stability coefficient W; the influence value of stability coefficient W is 0.15-0.2.

[0050] 4) Based on the constraints: index content and price gradient changes, calculate the adjusted price of lime; the constraints are as follows:

[0051] CaO content is between 88% and 100%. Taking 88% as the base amount, the price increases by 0.8 yuan / ton for every 0.1% increase.

[0052] The CaO content is between 85% and 88%. Taking 88% as the base amount, the price will be reduced by 1 yuan / ton for every 0.1% reduction.

[0053] The CaO content is between 80% and 85%, with 88% as the base amount. The price will be reduced by 5 yuan / ton for every 0.1% reduction.

[0054] The CaO content is 75%-80%, and the price is 50 yuan / ton;

[0055] The SiO2 content is based on 2.5%, and the price decreases by 1 yuan / ton for every 0.1% increase;

[0056] The sulfur content is based on 0.05%, and the price will decrease by 1 yuan / ton for every 0.01% increase;

[0057] The burning loss is based on 5% as the base amount, and the price will be reduced by 0.5 yuan / ton for every 0.1% increase;

[0058] The active content is 300-350ml, with 350ml as the base amount, the price will be reduced by 1 yuan / ton for every 1ml reduction;

[0059] The active content is between 250-300ml, with 350ml as the base amount, the price will be reduced by 2 yuan / ton for every 1ml reduction;

[0060] The active content is between 200-250ml, with 350ml as the base amount, and the price will be reduced by 3 yuan / ton for every 1ml reduction;

[0061] The particle size of the lime is based on 20-50 mm. The lime with a particle size less than 20 mm and / or a particle size greater than 50 mm and whose weight exceeds 5% of the total weight of the lime is deducted for settlement.

[0062] 5) According to the value of effective oxide tonnage of lime = adjusted price of lime / effective oxide content of lime, the value of effective oxide tonnage of lime is obtained;

[0063] The lower the effective oxide ton value of lime, the higher the quality cost performance of lime. Table 1 lists the manufacturers selected according to the effective oxide ton value of lime listed in the present invention.

[0064] The invention provides a method for adding and using white lime, which comprises the following steps: adding the white lime in 2-4 batches, adding the first batch of white lime within 1-3 minutes of blowing, and the amount of the first batch of white lime is 1 / 2 of the total amount of the white lime added; then adding 1 / 4-1 / 2 of the total amount of the white lime each time, and adding the remaining 1 / 2 of the total amount of the white lime within 4-6 minutes.

[0065] Furthermore, the total amount of lime added is as follows: when the effective oxide content of lime is ≥110%, the amount of lime added is 43kg / ton of steel; when the effective oxide content of lime is 100-109%, the amount of lime added is 47kg / ton of steel; when the effective oxide content of lime is 90-100%, the amount of lime added is 53kg / ton of steel.

[0066] Table 1

[0067] Material White ash White ash White ash factory Manufacturer 1 Manufacturer 2 Manufacturer 3 CaO 90.09 86.44 89.41 Available CaO 86.45 77.67 86.06 SiO2 1.21 2.92 1.11 Burn reduction 3.78 3.42 4.97 S 0.02 0.07 0.02 Activity 376 353 369 granularity 90 95 93 stability 0.66 0.56 0.88 unit price 580 580 580 Ingredients plus or minus 123.3 68.1 113.1 Adjusted price 703 648 693 Available Oxidants 115.6 93.9 113.0 Ton price of effective oxide 6.09 6.90 6.13 Value Ranking 1 3 2

[0068] The above table shows the results of testing and evaluating the lime indicators of Manufacturer 1, Manufacturer 2, and Manufacturer 3. Manufacturer 1, which ranks first in value, is selected for purchase because the effective oxide content of Manufacturer 1 is 115.6%. When the effective oxide content of lime is ≥110%, the amount of lime added is 43kg / ton of steel.

[0069] For any technician familiar with the art, without departing from the scope of the technical solution of the present invention, the technical content disclosed above can be used to make many possible changes and modifications to the technical solution of the present invention, or modified into equivalent embodiments with equivalent changes. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention should still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A multi-dimensional evaluation method for the quality of lime for steelmaking, characterized in that: The following steps are involved: 1) Obtain the data values ​​of six indicators of lime from the inspection and testing indicator library: CaO content, SiO2 content, sulfur content, loss on ignition, activity, and particle size qualification rate; 2) According to the formula, calculate the impact values ​​of the six indicators respectively; 3) Calculate the effective oxide content of lime according to the influence values ​​of the six indicators obtained in step 2), where the effective oxide content of lime = the influence value of effective CaO% content + the influence value of sulfur content + the influence value of loss on ignition + the influence value of activity + the influence value of particle size + the influence value of stability coefficient W; 4) Based on the constraints: index content and price gradient changes, calculate the adjusted price of lime; 5) According to the value of effective oxide tonnage of lime = adjusted price of lime / effective oxide content of lime, the value of effective oxide tonnage of lime is obtained; The lower the effective oxide ton value of lime, the higher the quality and cost performance of lime. The formula in step 2) is: Effective CaO% content influence value = lime CaO% - R × lime SiO2%, R is slag basicity; Sulfur content impact value = sulfur content * 0.2; Impact value of loss on burning = (loss on burning - 5) * 17 / 20; Activity impact value = (activity - 300) * 10 / 30; Particle size impact value = (particle size qualified rate - 90%) * 0.1; In step 3), the influence value of the stability coefficient W is 0.15-0.2; The constraints in step 4) are as follows: CaO content is between 88% and 100%. Taking 88% as the base amount, the price increases by 0.8 yuan / ton for every 0.1% increase. The CaO content is between 85% and 88%. Taking 88% as the base amount, the price will be reduced by 1 yuan / ton for every 0.1% reduction. The CaO content is between 80% and 85%, with 88% as the base amount. The price will be reduced by 5 yuan / ton for every 0.1% reduction. The CaO content is 75%-80%, and the price is 50 yuan / ton; The SiO2 content is based on 2.5%, and the price decreases by 1 yuan / ton for every 0.1% increase; The sulfur content is based on 0.05%, and the price will decrease by 1 yuan / ton for every 0.01% increase; The burning loss is based on 5% as the base amount, and the price will be reduced by 0.5 yuan / ton for every 0.1% increase; The active content is 300-350ml, with 350ml as the base amount, the price will be reduced by 1 yuan / ton for every 1ml reduction; The active content is between 250-300ml, with 350ml as the base amount, the price will be reduced by 2 yuan / ton for every 1ml reduction; The active content is between 200-250ml, with 350ml as the base amount, and the price will be reduced by 3 yuan / ton for every 1ml reduction; The particle size of the lime is based on 20-50 mm. The lime with a particle size less than 20 mm and / or a particle size greater than 50 mm and whose weight exceeds 5% of the total weight of the lime is deducted for settlement.

2. The multi-dimensional evaluation method for the quality of lime for steelmaking according to claim 1, characterized in that: The R value is 2.6-3.

0.

3. A method for adding and using the lime obtained by the evaluation method according to any one of claims 1 to 2, characterized in that: The method for adding the lime is as follows: adding the lime in 2-4 batches, adding the first batch of lime within 1-3 minutes of blowing, the amount of which is 1 / 2 of the total amount of lime added; then adding 1 / 4-1 / 2 of the total amount of lime each time, and adding the remaining 1 / 2 of the total amount of lime within 4-6 minutes.

4. The method for adding and using lime according to claim 3, characterized in that: The total amount of lime added is as follows: when the effective oxide content of lime is ≥110%, the amount of lime added is 43kg / ton of steel; when the effective oxide content of lime is 100-109%, the amount of lime added is 47kg / ton of steel; when the effective oxide content of lime is 90-100%, the amount of lime added is 53kg / ton of steel.

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