A production method of adding high proportion of brown iron ore ultra-thick layer acid sintered ore

Abstract

The present application belongs to the technical field of sinter production, and particularly relates to a production method of acid sinter with high proportion of limonite and super-thick layer. 75% limonite powder, 5% magnetite powder and 20% blast furnace return fines are mixed, and the sintering flux proportion, solid fuel proportion and sintering return fines proportion are adjusted according to the sinter composition control standards to prepare sintered mixed and uniform material. The mixed and uniform material is mixed and granulated under steam pressurized water, and ignition sintering is performed under high temperature conditions. The present application can solve the problems of poor sinter strength, poor reducibility and high solid fuel consumption during the production of acid sinter with high proportion of limonite. Through the production process control of thick layer, low moisture and slow machine speed, the super-thick layer sintering of acid sinter with high proportion of limonite can be realized. In the mode of ensuring low cost of acid sinter production, the strength of acid sinter is comprehensively improved, which provides support for stable operation of blast furnace and cost reduction.

Description

Technical Field

[0001] This invention belongs to the field of sinter production technology, specifically relating to a production method for acidic sinter with an ultra-thick layer of limonite added in high proportion. Background Technology

[0002] Currently, the conventional charge structure for blast furnace production in steel enterprises mainly consists of basic sinter, supplemented with acidic pellets, lump ore, and coke. Combining basic sinter with acidic pellets and lump ore can effectively increase the sinter feed ratio, achieving an overall sinter feed ratio of 90%–100%. However, pellets are costly, and lump ore has poor metallurgical properties. Therefore, increasing the amount of sinter is usually necessary to reduce ironmaking costs, with sinter often accounting for 60%–80% of the charge. As clinker, sinter has good low-temperature reduction and pulverization properties, which greatly helps reduce the blast furnace fuel ratio and increase iron production.

[0003] Traditional acidic sinters are produced by sintering iron concentrate or rich ore powder with little or no flux. Their main binder phase is fritillary olivine, which exhibits good hot strength. However, due to the high heat required for their mineralization mechanism, acidic sinters have a high FeO content, poor reducibility, poor cold strength, and high solid fuel consumption during sintering. For example, Chinese patent CN113005284A provides a method for applying titanium-containing sea sand in sinter production, solving the problem of sea sand powder application in sintering, increasing the proportion of sea sand used, and improving the drum strength and RDI of the sinter. +3.15 And reducing properties. However, it uses sea sand ore with a high Ti content, which improves the overall strength of acidic sinter with an alkalinity below 0.8, but the increased Ti content will lead to an increase in the overall fuel consumption of the blast furnace.

[0004] Limonite, a major raw material in sintering, originates from Australia. Due to its coarse particle size distribution and relatively low cost, it is widely used in sintering production, accounting for 40%–70% of the ore powder used. Current production practice shows that limonite sinter is generally suitable for high-basicity sintering. A high proportion of limonite significantly helps increase sinter yield, improve the permeability of the sinter bed, increase vertical sintering speed, and reduce sintering blending costs. However, its high proportion leads to excessively rapid vertical sintering speed and excessively low sintering negative pressure, causing the liquid phase formation and solidification rates to be too fast during the sintering process. This results in poor physical strength and metallurgical properties of the sinter, increased solid fuel consumption, and a series of other negative effects. Thick-layer sintering technology, as the mainstream process technology in current sintering production, greatly helps reduce solid fuel consumption due to the automatic heat storage effect of the middle and lower layers. Meanwhile, the slow machine speed and low moisture content process control requirements of the thick material layer technology are of great help in improving the thickness of the sintered over-wet layer and ensuring the full formation and consolidation of the liquid phase of the sinter. Therefore, the thick material layer sintering technology is of great help in improving the strength of sinter and reducing the consumption of solid fuel in sintering. Summary of the Invention

[0005] To address the above technical problems, the purpose of this invention is to provide a method for producing acidic sintered limonite, and more specifically, a method for producing acidic sintered ore with a high proportion of limonite in an ultra-thick layer.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A method for producing acidic sinter with a high proportion of limonite ultra-thick bed includes the following steps:

[0008] 1. Limonite powder, magnetite powder and blast furnace return ore are mixed in a mixing yard to prepare a sintering mixture, wherein limonite accounts for 75%, magnetite accounts for 5%, and blast furnace return ore accounts for 20%.

[0009] 2. The sintering mixture from step 1 is mixed with sintering feedstock, flux, solid fuel, and sintering return ore, and water is added to prepare a sintering homogenized material. The sintering homogenized material contains 88%–90% sintering mixture, 5.2%–5.6% solid fuel, 3.6%–3.8% raw flux, 1.2%–1.5% cooked flux, and 18%–22% sintering return ore.

[0010] 3. The binary basicity of the acidic sinter is adjusted by adjusting the ratio of the quenching flux, controlling the CaO / SiO2 ratio of the acidic sinter to be 0.50–0.55 times and the SiO2 ratio to be 6.5%–7.0%. The MgO content in the acidic sinter is adjusted by adjusting the ratio of magnesite, and the MgO content is adjusted according to the Al2O3 content in the acidic sinter, controlling the MgO:Al2O3 ratio to be 1.1:1–1.3:1. The FeO content in the acidic sinter is controlled to be 13% ± 1% by adjusting the ratio of solid fuel. The raw flux is magnesite, and the quenching flux is quicklime. In the production method of this invention, the mixing of the material with water is carried out in a primary and secondary mixing drum mixer, and steam pressurization of water is used for granulation and pelletizing. The ratio of water added to the primary and secondary mixing drums is 7:3.

[0011] 4. Place the sintering mixture onto the sintering machine table and ignite for sintering. The process control standards for the sintering process are as follows: sintering negative pressure is controlled at -14±1kPa, ignition temperature is controlled at 1050±50℃, sintering material layer thickness is 850~960mm, bottom material thickness is 80mm, sintering machine speed is 1.22~1.55m / min, sintering mixture moisture content is 6.6%~7.2%, sintering ignition negative pressure is -6±1kPa, sintering exhaust gas temperature is 140±20℃, and the sintering endpoint temperature is controlled in the second to last wind box, with an endpoint temperature control standard of 435±15℃.

[0012] To compensate for the excessively large particle size of the sintering mixture caused by the addition of a high proportion of limonite, which has an adverse effect on the quality and strength of the sinter due to excessive permeability during the sintering process, 5% magnetite concentrate is appropriately added. This achieves a comprehensive adjustment of the particle size of the mixture, improves the adverse effects of excessive permeability of the material layer during the sintering process, and at the same time, utilizes the exothermic characteristics of the magnetite decomposition process to help reduce the proportion of solid fuel.

[0013] The present invention provides a method for producing acidic sinter with a high proportion of limonite powder in an ultra-thick layer, which can further improve the overall feed ratio of sinter and effectively reduce the overall production cost of blast furnace hot metal when sinter has a cost advantage over pellets and lump ore.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0015] This invention provides a method for producing acidic sinter with an ultra-thick bed of high-proportion limonite powder. This method solves problems such as insufficient formation of the sintering liquid phase due to excessively high permeability of the sintering bed and excessively fast vertical sintering speed during the production of acidic sinter with a high proportion of limonite powder. It effectively improves the poor cold strength, poor reducibility, and high solids fuel consumption of acidic sinter produced with a high proportion of limonite powder. Simultaneously, it applies the low-water, thick-bed production process of basic sinter to the production of acidic sinter, effectively helping to improve the overall strength of the sinter and reduce fuel consumption. The drum strength is increased by 6.05%, the reducibility ratio (RI) is increased by 10%, and solids fuel consumption is reduced by 3.8 kg / t. This provides strong technical support for producing low-cost, high-quality acidic sinter and for achieving the goal of increasing the blast furnace sinter feed ratio by combining basic and acidic sinter. This invention has a simple structure, is highly operable, and has broad application potential. Detailed Implementation

[0016] The technical solutions in the embodiments of the present invention will be described in detail below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] A method for producing acidic sinter with an ultra-thick layer of high-proportion limonite powder includes:

[0018] (1) Limonite powder, magnetite powder and blast furnace return ore are mixed in a mixing yard to prepare a sintering mixture. The ore blending scheme of the sintering mixture is: 75% limonite, 5% magnetite and 20% blast furnace return ore.

[0019] (2) The sintering mixture is mixed with solid fuel, raw flux, cooked flux, and sintering return ore by adding water and granulating to form a sintering homogenized material. The ore blending scheme of the sintering homogenized material is as follows: sintering mixture accounts for 88-90%, solid fuel accounts for 5.2%-5.6%, raw flux accounts for 3.6%-3.8%, cooked flux accounts for 1.2%-1.5%, and sintering return ore accounts for 18-22%.

[0020] (3) The composition of acidic sinter is as follows: the SiO2 content of acidic sinter is 6.5% to 7.0%, and the binary basicity CaO / SiO2 ratio is 0.50, which is achieved by adjusting the ratio of the raw flux. The MgO content in acidic sinter is adjusted by adjusting the ratio of the raw flux, and the MgO content is adjusted according to the Al2O3 content in acidic sinter, controlling the MgO:Al2O3 ratio of acidic sinter to be 1.1:~1.3:1; the FeO content in acidic sinter is controlled at 13% ± 1% by adjusting the ratio of solid fuel.

[0021] (4) The sintering process control standards for acidic sintered ore production are as follows: sintering negative pressure is controlled at -14±1kPa, ignition temperature is controlled at 1050±50℃, sintering material layer thickness is 850~960mm, bottom material thickness is 80mm, sintering machine speed is 1.22~1.55m / min, sintering mixed material moisture content is 6.6%~7.2%, the addition of water to the mixed material is carried out in the first and second mixing drum mixers, steam pressurized water is used for granulation and pelletizing, the water addition ratio is 7:3, sintering ignition negative pressure is -6±1kPa, sintering exhaust gas temperature is 140±20℃, the sintering endpoint temperature is controlled in the second to last wind box, and the endpoint temperature is controlled at 435±15℃.

[0022] (5) The entire sintering process, including mixing and granulation, ignition and sintering, crushing and cooling, screening and granulation, and finished product discharge, is carried out in accordance with the above ore blending scheme, component control standards and sintering process standards.

[0023] Example 1

[0024] A method for producing acidic sinter with an ultra-thick layer of high-proportion limonite powder includes:

[0025] (1) Limonite powder, magnetite powder and blast furnace return ore are mixed in a mixing yard to prepare a sintering mixture. The ore blending scheme of the sintering mixture is: 75% limonite, 5% magnetite and 20% blast furnace return ore.

[0026] (2) The sintering mixture, solid fuel, raw flux, cooked flux, and sintering return ore are mixed with water and granulated to form a sintering homogenized material. The ore blending scheme of the sintering homogenized material is as follows: sintering mixture accounts for 89.1%, solid fuel accounts for 5.6%, raw flux accounts for 3.8%, cooked flux accounts for 1.5%, and sintering return ore accounts for 22%. The composition of the acidic sinter is as follows: acidic sinter SiO2 content 6.7%, binary basicity CaO / SiO2 = 0.52, acidic sinter MgO:Al2O3 = 1.22, Al2O3 content 2.40%, and FeO content 13.88%.

[0027] (3) The sintering process control standards for acidic sintered ore production are as follows: sintering negative pressure is controlled at -13.20 kPa, ignition temperature is controlled at 1025℃, sintering material layer thickness is 850 mm, bottom material thickness is 80 mm, sintering machine speed is 1.55 m / min, sintering mixed material moisture content is 7.2%, the addition of water to the mixed material is carried out in the first and second mixing drum mixers, steam pressurized water is used for granulation and pelletizing, the water addition ratio is 7:3, sintering ignition negative pressure is -6 kPa, sintering exhaust gas temperature is 160℃, sintering endpoint temperature is controlled in the second to last wind box, and endpoint temperature is controlled at 450℃.

[0028] (4) The entire sintering process, including mixing and granulation, ignition and sintering, crushing and cooling, screening and granulation, and finished product discharge, is carried out in accordance with the above ore blending scheme, component control standards and sintering process standards.

[0029] Example 2

[0030] A method for producing acidic sinter with an ultra-thick layer of high-proportion limonite powder includes:

[0031] (1) Limonite powder, magnetite powder and blast furnace return ore are mixed in a mixing yard to prepare a sintering mixture. The ore blending scheme of the sintering mixture is: 75% limonite, 5% magnetite and 20% blast furnace return ore.

[0032] (2) The sintering mixture is mixed with solid fuel, raw flux, cooked flux, and sintering return ore by adding water and granulating to form a sintering homogenized material. The ore blending scheme of the sintering homogenized material is as follows: sintering mixture accounts for 89.4%, solid fuel accounts for 5.5%, raw flux accounts for 3.7%, cooked flux accounts for 1.4%, and sintering return ore accounts for 21%.

[0033] The composition of the acidic sinter is as follows: SiO2 content 6.74%, binary basicity CaO / SiO2 = 0.51, MgO:Al2O3 = 1.17, Al2O3 content 2.50%, and FeO content 13.62%.

[0034] (3) The sintering process control standards for acidic sintered ore production are as follows: sintering negative pressure is controlled at -13.85 kPa, ignition temperature is controlled at 1025℃, sintering material layer thickness is 900 mm, bottom material thickness is 80 mm, sintering machine speed is 1.38 m / min, sintering mixed material moisture content is 7.0%, the addition of water to the mixed material is carried out in the first and second mixing drum mixers, steam pressurized water is used for granulation and pelletizing, the water addition ratio is 7:3, sintering ignition negative pressure is -6 kPa, sintering exhaust gas temperature is 155℃, sintering endpoint temperature is controlled in the second to last wind box, and endpoint temperature is controlled at 440℃.

[0035] (4) The entire sintering process, including mixing and granulation, ignition and sintering, crushing and cooling, screening and granulation, and finished product discharge, is carried out in accordance with the above ore blending scheme, component control standards and sintering process standards.

[0036] Example 3

[0037] A method for producing acidic sinter with an ultra-thick layer of high-proportion limonite powder includes:

[0038] (1) Limonite powder, magnetite powder and blast furnace return ore are mixed in a mixing yard to prepare a sintering mixture. The ore blending scheme of the sintering mixture is: 75% limonite, 5% magnetite and 20% blast furnace return ore.

[0039] (2) The sintering mixture is mixed with solid fuel, raw flux, cooked flux, and sintering return ore by adding water and granulating to form a sintering homogenized material. The ore blending scheme of the sintering homogenized material is as follows: sintering mixture accounts for 89.4%, solid fuel accounts for 5.4%, raw flux accounts for 3.7%, cooked flux accounts for 1.5%, and sintering return ore accounts for 19%.

[0040] The composition of the acidic sinter is as follows: SiO2 content 6.72%, binary basicity CaO / SiO2 0.53, MgO:Al2O3 = 1.18, Al2O3 content 2.50%, and FeO content 13.35%.

[0041] (3) The sintering process control standards for acidic sintered ore production are as follows: sintering negative pressure is controlled at -14.50 kPa, ignition temperature is controlled at 1050±50℃, sintering material layer thickness is 900 mm, bottom material thickness is 80 mm, sintering machine speed is 1.28 m / min, sintering mixed material moisture content is 7.0%, the addition of water to the mixed material is carried out in the first and second mixing drum mixers, steam pressurized water is used for granulation and pelletizing, the water addition ratio is 7:3, sintering ignition negative pressure is -6 kPa, sintering exhaust gas temperature is 145℃, sintering endpoint temperature is controlled in the second to last wind box, and endpoint temperature is controlled at 420℃.

[0042] (4) The entire sintering process, including mixing and granulation, ignition and sintering, crushing and cooling, screening and granulation, and finished product discharge, is carried out in accordance with the above ore blending scheme, component control standards and sintering process standards.

[0043] Example 4

[0044] A method for producing acidic sinter with an ultra-thick layer of high-proportion limonite powder includes:

[0045] (1) Limonite powder, magnetite powder and blast furnace return ore are mixed in a mixing yard to prepare a sintering mixture. The ore blending scheme of the sintering mixture is: 75% limonite, 5% magnetite and 20% blast furnace return ore.

[0046] (2) The sintering mixture is mixed with solid fuel, raw flux, cooked flux, and sintering return ore by adding water and granulating to form a sintering homogenized material. The ore blending scheme of the sintering homogenized material is as follows: sintering mixture accounts for 89.7%, solid fuel accounts for 5.2%, raw flux accounts for 3.6%, cooked flux accounts for 1.5%, and sintering return ore accounts for 18%.

[0047] The composition of the acidic sinter is as follows: SiO2 content 6.76%, binary basicity CaO / SiO2 0.52, MgO:Al2O3 = 1.22, Al2O3 content 2.30%, and FeO content 13.22%.

[0048] (3) The sintering process control standards for acidic sintered ore production are as follows: sintering negative pressure is controlled at -14.20 kPa, ignition temperature is controlled at 1025℃, sintering material layer thickness is 900 mm, bottom material thickness is 80 mm, sintering machine speed is 1.22 m / min, sintering mixed material moisture content is 7.0%, the addition of water to the mixed material is carried out in the first and second mixing drum mixers, steam pressurized water is used for granulation and pelletizing, the water addition ratio is 7:3, sintering ignition negative pressure is -6 kPa, sintering exhaust gas temperature is 140℃, sintering endpoint temperature is controlled in the second to last wind box, and endpoint temperature is controlled at 440℃.

[0049] (4) The entire sintering process, including mixing and granulation, ignition and sintering, crushing and cooling, screening and granulation, and finished product discharge, is carried out in accordance with the above ore blending scheme, component control standards and sintering process standards.

[0050] Table 1 Comparison of sintering process parameters under different embodiments

[0051]

[0052] Table 2 Comparison of sinter quality, strength, metallurgical properties, and fuel consumption under different implementation ratios

[0053] Drum / % <![CDATA[RDI +3.15 / %]]> Reducing power / % Solid fuel consumption / kg / t Example 1 59.45 71.72 60.05 65.26 Example 2 60.65 68.45 62.58 64.15 Example 3 63.7 69.55 65.65 62.32 Example 4 65.5 70.45 70.50 61.46

[0054] Comparison of sintering process parameters and sinter strength, metallurgical properties, and solid fuel consumption shows that in the production of acidic sinter with a high proportion of limonite, as the thickness of the sintering bed gradually increases, the moisture content decreases, and the sintering machine speed slows down, the overall sintering process parameters meet the control requirements, the sinter composition meets the process control requirements, the sinter drum strength and reducibility are significantly improved, and the sinter solid fuel consumption is reduced. Compared with Scheme 1 and Scheme 4, the sintering exhaust gas temperature decreases by 20℃, the sintering negative pressure increases by -1kPa, the sintering endpoint temperature decreases slightly by 10℃, the sinter internal return rate decreases by 4%, the sinter drum strength increases by 6.05, and the sinter low-temperature reduction pulverization RDI is improved. +3.15The process is relatively stable, with a 10.45 increase in reducibility (RI) and a 3.8 kg / t decrease in solid fuel consumption. As the material layer thickness increases, the overall sintering negative pressure is improved, which can effectively address issues such as insufficient formation of the sintering liquid phase caused by excessive permeability of the sintering material layer and excessively fast vertical sintering speed during the acidic sintering process. As the moisture content of the mixed material decreases, the excessively wet layer during sintering is reduced, avoiding the adverse effects of excessive permeability caused by a thick material layer, thus ensuring appropriate permeability during the sintering production process. As the sintering machine speed decreases, the sufficient formation and solidification of the liquid phase during sintering is ensured, thus guaranteeing the overall strength of the sinter.

[0055] This invention addresses the immense pressure of current sintering production cost control by utilizing a high proportion of limonite to produce acidic sinter. Combined with the application of high-basicity sinter thick-layer production technology, this invention improves the overall drum strength and reducibility of acidic sinter while reducing sinter solid fuel consumption under a low-cost production model. Furthermore, it explores the control standards for various production process parameters under the high-proportion limonite acidic sinter production model, enabling a blast furnace burden structure of 74% basic sinter + 19% acidic sinter + 7% lump ore. Given the high cost of pelletizing, this invention provides a production reference for comprehensively reducing blast furnace burden costs in the ironmaking system.

[0056] The implementation method is merely an illustrative example of this patent and does not limit its scope of protection. Those skilled in the art can make partial modifications to it. As long as they do not exceed the spirit and essence of this patent, they are considered equivalent substitutions to this patent and are all within the scope of protection of this patent.

Claims

1. A method for producing high proportion of brown iron ore ultra thick bedded acid sintered ore, characterized by: Includes the following steps: (1) 75% of limonite powder, 5% of magnetite powder and 20% of blast furnace return ore are mixed in a mixing yard to form a sintering mixture; the sintering mixture is mixed with flux, solid fuel and sintering return ore, and water is added in the first and second mixing drum mixers to form a sintering mixture. The sintering blending scheme is as follows: sintering mixture accounts for 89.1%–90%, solid fuel accounts for 5.2%–5.6%, raw flux accounts for 3.6%–3.8%, and cooked flux accounts for 1.2%–1.5%. The ratio of internal return ore to the internal return balance and the sum of the first four is (18%–22%):100%. The binary basicity of acidic sinter (CaO / SiO2) is controlled at 0.50–0.55, the SiO2 content is controlled at 6.5%–7.0%, the MgO:Al2O3 ratio is controlled at 1.1:1–1.3:1, and the FeO content is controlled at 12%–14%. (2) After the sintering mixture is spread out, the fire is ignited and the air is drawn for sintering. The sintering negative pressure is controlled at -13 to -15 kPa, the ignition temperature is controlled at 1000 to 1100℃, the sintering machine speed is 1.22 to 1.55 m / min, the sintering ignition negative pressure is -5 to -7 kPa, the sintering exhaust gas temperature is 120 to 160℃, the sintering endpoint temperature is controlled in the second to last wind box, and the endpoint temperature control standard is 420 to 450℃. (3) Crushing and cooling, screening and granulation, and finished product output.

2. A method of producing high proportion of limonite acid sintered ore with super-thick layer as claimed in claim 1, wherein: The binary basicity of acidic sinter is adjusted by adjusting the ratio of molten flux; the ratio of MgO to Al2O3 in acidic sinter is adjusted by adjusting the ratio of raw flux; and the FeO content of acidic sinter is controlled by adjusting the ratio of solid fuel.

3. The production method of acidic sinter with a high proportion of limonite ultra-thick material layer according to claim 1, characterized in that: The raw flux is magnesite; the slaked flux is quicklime.

4. A method of producing high proportion of limonite acid sintered ore with super-thick layer as claimed in claim 1, wherein: The ratio of water added to the first mixture to water added to the second mixture is 7:3; the moisture content of the sintered mixture is 6.6% to 7.2%.

5. A method of producing high proportion of limonite acid sintered ore with super-thick layer as claimed in claim 1, wherein: The pelletizing and pelletizing process is carried out using steam pressurized water.

6. A method of producing high proportion of limonite acid sintered ore with super-thick layer as claimed in claim 1, wherein: The thickness of the sintering material layer is 850-960mm, and the thickness of the base material is 80mm.

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