Iron-making furnace charge structure for realizing high-proportion smelting of bayan obo ore by blast furnace based on high-ball-ratio technology

Abstract

The invention discloses an iron-making furnace charge structure for realizing high-proportion smelting of bayan obo ore in a blast furnace based on a high-pellet-ratio technology, which comprises the following steps of: filling iron-making raw materials into the blast furnace according to a furnace charge structure mode of 45% of sintered ore and 55% of pellet ore, and then carrying out iron-making production; in the blast furnace ironmaking production process, reasonable material distribution, air supply, coal injection and slagging operation systems are assisted, and the furnace charge structure is controlled to be 45% of sintered ore, 42%-48% of alkaline pellet ore and 7%-13% of acid pellet ore; normal tapping; and the mass percent components of the sintered ore, the acid pellet ore and the alkaline pellet ore are limited. By regulating and controlling the proper ratio of the acid pellets to the alkaline pellets in the blast furnace ironmaking furnace charge structure, the reduction performance, the low-temperature reduction degradation performance and the soft melting dripping performance of the steel-covered blast furnace comprehensive furnace charge are improved, the comprehensive furnace charge breathability and the blast furnace gas utilization rate are improved, and the blast furnace ironmaking fuel ratio and the production cost are reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of blast furnace ironmaking, and in particular relates to an ironmaking charge structure for realizing high-proportion smelting of Bayan Obo ore in a blast furnace based on a high spherical ratio technology. Background Art

[0002] At present, Baosteel still produces crude steel by smelting Bayan Obo ore in the traditional long process of "blast furnace-converter". The blast furnace ironmaking charge is the alkaline sinter produced by the sintering process and the acidic pellet produced by the pelletizing process. The structural ratio is basically "70% sinter + 30% acidic pellet", and the proportion of Bayan Obo ore in the furnace smelting is about 40%. With the in-depth implementation of Baosteel's environmental protection policy, the green policy drive of energy conservation and carbon reduction, and the enterprise development direction of increasing the proportion of its own mineral resources to achieve continuous cost reduction in the ironmaking process, Baosteel relies on the characteristics of Bayan Obo ore "high calcium and low silicon" (natural alkalinity of about 2.0), and improves the process of pellet production process and blast furnace ironmaking process, develops and applies alkaline pellets and blast furnace high-ball ratio smelting technology, and the proportion of pellets in blast furnace ironmaking charge and the proportion of Bayan Obo ore in the furnace smelting reaches 55%.

[0003] From the perspective of process technology and actual production operation, for blast furnace ironmaking process, reasonable charge structure is the basis for the stable and smooth operation of blast furnace, and it is also the premise for blast furnace ironmaking to achieve energy conservation and emission reduction goals. Since the optimization of charge structure directly affects the various technical and economic indicators of blast furnace ironmaking, in actual production, a reasonable charge structure is more important than regulating the metallurgical properties of a single iron-containing charge. Long-term production practice and scientific research have shown that in the process of production and operation, enterprises need to continuously adjust and update the blast furnace charge structure according to their own ironmaking technology development direction, ironmaking raw material sources and characteristics in order to obtain the greatest economic benefits. Therefore, Baosteel's application of high-ball ratio technology to achieve high-proportion smelting of Bayan Obo ore in blast furnaces must match the corresponding reasonable charge structure to maximize the production efficiency of Baosteel's blast furnaces and optimize the indicators. Summary of the invention

[0004] In order to solve the above technical problems, the purpose of the present invention is to provide an ironmaking charge structure for realizing high-proportion smelting of Bayan Obo ore in a blast furnace based on high spherical ratio technology.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] The present invention discloses an ironmaking charge structure for realizing high-proportion smelting of Bayan Obo ore in a blast furnace based on a high spherical ratio technology, comprising:

[0007] (1) charging ironmaking raw materials into a blast furnace according to a charge structure pattern of 45% sintered ore + 55% pelletized ore, and then carrying out ironmaking production;

[0008] (2) A reasonable auxiliary distribution, air supply, coal injection and slag making operation system is adopted in the blast furnace ironmaking production process to control the charge structure to 45% sintered ore + 42%-48% alkaline pellets + 7%-13% acidic pellets;

[0009] (3) Normal iron tapping;

[0010] (4) in terms of mass percentage, the sintered ore produced in the sintering process has a TFe content of not less than 54.1%, a FeO content of 7.5%-9.5%, a CaO content of 11.0%-12.0%, a SiO2 content of 5.0%-5.5%, an Al2O3 content of 1.5%-2.0%, a K2O content of 0.10%-0.30%, a Na2O content of 0.05%-0.30%, a F component content of 0.05%-0.20%, a MgO content of 2.00%, and a binary free alkalinity of 2.20;

[0011] (5) The acidic pellets produced in the pelletizing process have a TFe content of not less than 62.1%, a FeO content of 1.4%-1.6%, a CaO content of 1.7%-1.9%, a SiO2 content of 4.3%-4.5%, an Al2O3 content of 0.9%-1.0%, a K2O content of 0.14%-0.15%, a Na2O content of 0.13%-0.14%, a F component content of 0.08%-0.10%, and a binary free alkalinity of 0.368, in terms of mass percentage;

[0012] (6) Calculated by mass percentage, the alkaline pellets produced in the pelletizing process have a TFe content of not less than 61.5%, a FeO content of 1.4%-1.5%, a CaO content of 3.0%-3.2%, a SiO2 content of 2.6%-2.7%, an Al2O3 content of 0.6%-0.7%, a K2O content of 0.12%-0.13%, a Na2O content of 0.14%-0.15%, a F component content of 0.10%-0.13%, and a binary free alkalinity of 1.10.

[0013] Furthermore, the binary free alkalinity calculation formulas for the sintered ore, acidic pellets and alkaline pellets described in (4), 5) and (6) are as follows:

[0014]

[0015] In the formula: R0 is the binary free alkalinity of sintered ore, acidic pellets and alkaline pellets, -; w(CaO) is the mass fraction of CaO in each iron-making raw material, %; w(F) is the mass fraction of F element in each iron-making raw material, %; w(SiO2) is the mass fraction of SiO2 in each iron-making raw material, %.

[0016] Furthermore, the chemical composition of the sintered ore in mass percentage is: TFe content is 54.58%, FeO content is 8.5%, CaO content is 11.44%, SiO2 content is 5.13%, Al2O3 content is 1.64%, K2O content is 0.15%, Na2O content is 0.13%, F component content is 0.10%, MgO content is 2.00%, and binary free alkalinity is 2.201.

[0017] Furthermore, the chemical composition of the sintered ore in mass percentage is: TFe content is 54.51%, FeO content is 8.46%, CaO content is 11.48%, SiO2 content is 5.16%, Al2O3 content is 1.68%, K2O content is 0.13%, Na2O content is 0.14%, F component content is 0.10%, MgO content is 1.98%, and binary free alkalinity is 2.196.

[0018] Furthermore, the chemical composition of the sintered ore in mass percentage is: TFe content is 54.32%, FeO content is 8.47%, CaO content is 11.63%, SiO2 content is 5.22%, Al2O3 content is 1.76%, K2O content is 0.14%, Na2O content is 0.12%, F component content is 0.09%, MgO content is 1.99%, and binary free alkalinity is 2.203.

[0019] Furthermore, the chemical composition of the sintered ore in mass percentage is: TFe content is 54.28%, FeO content is 8.49%, CaO content is 11.64%, SiO2 content is 5.23%, Al2O3 content is 1.82%, K2O content is 0.13%, Na2O content is 0.12%, F component content is 0.08%, MgO content is 1.99%, and binary free alkalinity is 2.203.

[0020] Furthermore, the chemical composition of the acidic pellets by mass percentage is: TFe content is 62.21%, FeO content is 1.50%, CaO content is 1.78%, SiO2 content is 4.45%, Al2O3 content is 0.98%, K2O content is 0.143%, Na2O content is 0.136%, F component content is 0.09%, and binary free alkalinity is 0.37.

[0021] Furthermore, the chemical composition of the alkaline pellets by mass percentage is: TFe content is 61.84%, FeO content is 1.47%, CaO content is 3.15%, SiO2 content is 2.69%, Al2O3 content is 0.67%, K2O content is 0.126%, Na2O content is 0.142%, F component content is 0.12%, and binary free alkalinity is 1.105.

[0022] The present invention adopts GB / T 13241-2017 "Method for Determining the Reducibility of Iron Ore" to test the comprehensive furnace charge reduction performance, GB / T 13242-2017 "Method for Using Cold Drum After Static Reduction in Low-Temperature Powdering Test of Iron Ore" to test the comprehensive furnace charge reduction pulverization performance, and GB / T 34211-2017 "Method for Determining the Dripping Performance of Soft Melting after High-Temperature Load Reduction of Iron Ore" to test the comprehensive furnace charge soft melting dripping performance. The reduction degree RI is an indicator for evaluating the comprehensive furnace charge reduction performance. The larger the RI value, the better the comprehensive furnace charge reduction performance. Reduction pulverization RDI -3.15mm RDI is an indicator for evaluating the comprehensive performance of charge reduction and pulverization. -3.15mm The smaller the value, the better the comprehensive charge reduction performance. 40 -T 10 To evaluate the comprehensive charge softening temperature range, T 10 The bigger, the T 40 -T 10 The smaller the temperature range, the better the comprehensive charge softening performance, which is conducive to the indirect reduction of the blast furnace block zone. D -T S To evaluate the comprehensive melting temperature range of furnace charge, T S The bigger, the T D -T S The smaller the temperature range, the better the comprehensive furnace charge melting performance, which is conducive to the downward movement of the blast furnace soft melting zone and the narrowing of the soft melting zone, promoting the improvement of blast furnace gas utilization. The S value is an indicator for evaluating the permeability of the comprehensive furnace charge soft melting zone. The smaller the S value, the better the permeability of the comprehensive furnace charge soft melting zone, which is conducive to the gas in the blast furnace passing through the soft melting zone and improving the gas utilization rate. The calculation formula of the comprehensive furnace charge S value is as follows:

[0023]

[0024] Where, S is the comprehensive permeability index of blast furnace charge, kPa·℃; △P T is the pressure difference of the material column corresponding to the charge temperature T, kPa; △P S is the pressure difference of the material column corresponding to the beginning of melting of the charge, kPa; T S is the melting start temperature, °C; T D is the final melting temperature, ℃.

[0025] Compared with the prior art, the beneficial technical effects of the present invention are:

[0026] The present invention forms a method for optimizing the charge structure of Baosteel's blast furnace with high ball ratio and high proportion for smelting Bayan Obo ore by regulating the appropriate ratio of acidic pellets to alkaline pellets in the charge structure of blast furnace ironmaking, thereby improving the comprehensive charge reduction performance, low-temperature reduction pulverization performance and soft melting dripping performance of Baosteel's blast furnace, which is beneficial to improving the comprehensive charge permeability and blast furnace gas utilization rate in the process of Baosteel's blast furnace with high ball ratio and high proportion for smelting Bayan Obo ore, and reducing the blast furnace ironmaking fuel ratio and production cost. DETAILED DESCRIPTION

[0027] The technical solution of the present invention is described in detail below in conjunction with the embodiments.

[0028] At present, the charge structure of Baosteel's blast furnace with high ball ratio and high ratio smelting of Bayan Obo ore is shown in Table 1. The chemical composition and metallurgical properties of various ironmaking raw materials are shown in Table 2 and Table 3. The comprehensive metallurgical properties analysis of the charge is shown in Table 1.

[0029] Example 1

[0030] Under the condition that the metallurgical properties of ironmaking raw materials meet the requirements of blast furnace production, the sintered ore and pelletized ore of Example 1 shown in Tables 2 and 3 are used as raw materials, and blast furnace ironmaking is carried out according to the charge structure mode of "45% sintered ore + 42% alkaline pelletized ore + 13% acidic pelletized ore". The metallurgical properties of the comprehensive charge of the blast furnace are tested to obtain its reducibility, low-temperature reduction pulverization performance and soft melting dripping performance, which are listed in Table 1. It can be seen that compared with the comprehensive charge structure of the high ball ratio and high proportion smelting of Bayan Obo ore in the current Baosteel blast furnace, the metallurgical properties of the optimized comprehensive charge of the blast furnace are improved.

[0031] Example 2

[0032] Under the condition that the metallurgical properties of ironmaking raw materials meet the requirements of blast furnace production, the sintered ore and pelletized ore of Example 2 shown in Table 2 and Table 3 are used as raw materials, and blast furnace ironmaking is carried out according to the charge structure mode of "45% sintered ore + 45% alkaline pelletized ore + 10% acidic pelletized ore". The metallurgical properties of the comprehensive charge of the blast furnace are tested to obtain its reducibility, low-temperature reduction pulverization performance and soft melting dripping performance, which are listed in Table 1. It can be seen that compared with the comprehensive charge structure of the high ball ratio and high proportion smelting of Bayan Obo ore in the current Baosteel blast furnace, the metallurgical properties of the optimized comprehensive charge of the blast furnace are improved.

[0033] Example 3

[0034] Under the condition that the metallurgical properties of ironmaking raw materials meet the requirements of blast furnace production, the sintered ore and pelletized ore of Example 3 shown in Tables 2 and 3 are used as raw materials, and blast furnace ironmaking is carried out according to the charge structure mode of "45% sintered ore + 48% alkaline pelletized ore + 7% acidic pelletized ore". The metallurgical properties of the comprehensive charge of the blast furnace are tested to obtain its reducibility, low-temperature reduction pulverization performance and soft melting dripping performance, which are listed in Table 1. It can be seen that compared with the comprehensive charge structure of the high ball ratio and high proportion smelting of Bayan Obo ore in the current Baosteel blast furnace, the metallurgical properties of the optimized comprehensive charge of the blast furnace are improved.

[0035] Table 1 Analysis of comprehensive charge structure and metallurgical properties of blast furnaces in Baosteel's current conditions (benchmark) and various embodiments of the present invention

[0036]

[0037] Table 2 Chemical composition and metallurgical properties of sintered ore used in Baosteel's current conditions (benchmark) and in various embodiments of the present invention

[0038]

[0039] Table 3 Chemical composition and metallurgical properties of pellets used in Baosteel's current conditions (benchmark) and in various embodiments of the present invention

[0040]

[0041] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. An ironmaking charge structure for realizing high-proportion smelting of Bayan Obo ore in a blast furnace based on high spherical ratio technology, characterized in that: include: (1) charging ironmaking raw materials into a blast furnace according to a charge structure pattern of 45% sintered ore + 55% pelletized ore, and then carrying out ironmaking production; (2) A reasonable auxiliary distribution, air supply, coal injection and slag making operation system is adopted in the blast furnace ironmaking production process to control the charge structure to 45% sintered ore + 42%-48% alkaline pellets + 7%-13% acidic pellets; (3) Normal iron tapping; (4) in terms of mass percentage, the sintered ore produced in the sintering process has a TFe content of not less than 54.1%, a FeO content of 7.5%-9.5%, a CaO content of 11.0%-12.0%, a SiO2 content of 5.0%-5.5%, an Al2O3 content of 1.5%-2.0%, a K2O content of 0.10%-0.30%, a Na2O content of 0.05%-0.30%, a F component content of 0.05%-0.20%, a MgO content of 2.00%, and a binary free alkalinity of 2.20; (5) The acidic pellets produced in the pelletizing process have a TFe content of not less than 62.1%, a FeO content of 1.4%-1.6%, a CaO content of 1.7%-1.9%, a SiO2 content of 4.3%-4.5%, an Al2O3 content of 0.9%-1.0%, a K2O content of 0.14%-0.15%, a Na2O content of 0.13%-0.14%, a F component content of 0.08%-0.10%, and a binary free alkalinity of 0.368, in terms of mass percentage; (6) Calculated by mass percentage, the alkaline pellets produced in the pelletizing process have a TFe content of not less than 61.5%, a FeO content of 1.4%-1.5%, a CaO content of 3.0%-3.2%, a SiO2 content of 2.6%-2.7%, an Al2O3 content of 0.6%-0.7%, a K2O content of 0.12%-0.13%, a Na2O content of 0.14%-0.15%, a F component content of 0.10%-0.13%, and a binary free alkalinity of 1.

10.

2. The ironmaking charge structure for realizing high-proportion smelting of Bayan Obo ore in a blast furnace based on high spherical ratio technology according to claim 1 is characterized in that: The binary free alkalinity calculation formula of the sintered ore, acidic pellets and alkaline pellets mentioned in (4), 5) and (6) is as follows: In the formula: R0 is the binary free alkalinity of sintered ore, acidic pellets and alkaline pellets, -; w(CaO) is the mass fraction of CaO in each iron-making raw material, %; w(F) is the mass fraction of F element in each iron-making raw material, %; w(SiO2) is the mass fraction of SiO2 in each iron-making raw material, %.

3. The ironmaking charge structure for realizing high-proportion smelting of Bayan Obo ore in a blast furnace based on high spherical ratio technology according to claim 1 is characterized in that: The chemical composition of the sintered ore by mass percentage is: TFe content is 54.58%, FeO content is 8.5%, CaO content is 11.44%, SiO2 content is 5.13%, Al2O3 content is 1.64%, K2O content is 0.15%, Na2O content is 0.13%, F component content is 0.10%, MgO content is 2.00%, and binary free basicity is 2.

201.

4. The ironmaking charge structure for realizing high-proportion smelting of Bayan Obo ore in a blast furnace based on high spherical ratio technology according to claim 1 is characterized in that: The chemical composition of the sintered ore by mass percentage is: TFe content is 54.51%, FeO content is 8.46%, CaO content is 11.48%, SiO2 content is 5.16%, Al2O3 content is 1.68%, K2O content is 0.13%, Na2O content is 0.14%, F component content is 0.10%, MgO content is 1.98%, and binary free basicity is 2.

196.

5. The ironmaking charge structure for realizing high-proportion smelting of Bayan Obo ore in a blast furnace based on high spherical ratio technology according to claim 1 is characterized in that: The chemical composition of the sintered ore by mass percentage is: TFe content is 54.32%, FeO content is 8.47%, CaO content is 11.63%, SiO2 content is 5.22%, Al2O3 content is 1.76%, K2O content is 0.14%, Na2O content is 0.12%, F component content is 0.09%, MgO content is 1.99%, and binary free basicity is 2.

203.

6. The ironmaking charge structure for realizing high-proportion smelting of Bayan Obo ore in a blast furnace based on high spherical ratio technology according to claim 1 is characterized in that: The chemical composition of the sintered ore by mass percentage is: TFe content is 54.28%, FeO content is 8.49%, CaO content is 11.64%, SiO2 content is 5.23%, Al2O3 content is 1.82%, K2O content is 0.13%, Na2O content is 0.12%, F component content is 0.08%, MgO content is 1.99%, and binary free basicity is 2.

203.

7. The ironmaking charge structure for realizing high-proportion smelting of Bayan Obo ore in a blast furnace based on high spherical ratio technology according to claim 1 is characterized in that: The chemical composition of the acidic pellets by mass percentage is: TFe content is 62.21%, FeO content is 1.50%, CaO content is 1.78%, SiO2 content is 4.45%, Al2O3 content is 0.98%, K2O content is 0.143%, Na2O content is 0.136%, F component content is 0.09%, and binary free alkalinity is 0.

37.

8. The ironmaking charge structure for realizing high-proportion smelting of Bayan Obo ore in a blast furnace based on high spherical ratio technology according to claim 1 is characterized in that: The chemical composition of the alkaline pellets by mass percentage is: TFe content is 61.84%, FeO content is 1.47%, CaO content is 3.15%, SiO2 content is 2.69%, Al2O3 content is 0.67%, K2O content is 0.126%, Na2O content is 0.142%, F component content is 0.12%, and binary free alkalinity is 1.105.

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