Sintered ore production process capable of reducing flux consumption

Abstract

The invention relates to the technical field of sintered ore production, in particular to a sintered ore production process capable of reducing flux consumption, which comprises the following steps: uniformly mixing and granulating a first mixture and a second mixture to obtain a third mixture, and distributing, igniting and sintering the third mixture to obtain sintered ore, wherein the first mixture comprises a part of iron ore powder, return mine, a part of flux and a part of fuel, and the part of iron ore powder comprises a part of fine-grain high-silicon iron ore powder and fine iron powder; the second mixture comprises residual iron ore powder, residual flux and residual fuel, and the residual iron ore powder comprises residual fine-grain high-silicon iron ore powder and coarse powder. By adjusting the proportioning ratio and the mixing mode, the flux consumption is reduced, and the drum index, RDI + 3.15 mm and sinter grade index of the sinter are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of sintered ore production, and in particular to a sintered ore production process capable of reducing flux consumption. Background Art

[0002] In blast furnace ironmaking, approximately 50% to 80% of the iron-containing material fed into the blast furnace is sintered ore. Sintered ore is the primary iron source. After sintering, the ore powder exhibits excellent permeability and reducibility, promoting efficient reduction reactions within the blast furnace, thereby effectively improving ironmaking efficiency and quality. Compared to other iron sources, such as pellets, sintered ore production offers advantages such as a wide range of ore powder resources, low costs, and high yields. For high-quality sintered ore, the blast furnace charge can be increased, for example, to 70% to 80%, to reduce ironmaking costs. For lower-quality sintered ore, the blast furnace charge should be reduced, for example, to 50% to 60%, and the quality of the molten iron can be controlled by increasing the use of more expensive pellets.

[0003] In a competitive market where cost reduction and efficiency improvement are universally demanded, there has been extensive research on reducing sinter solids consumption and process energy consumption without compromising sinter quality. However, research on sinter flux consumption is less in-depth. Fluxes in traditional sinter mixes primarily include quicklime, limestone, dolomite, and serpentine. In high-alkalinity sinter production, total flux consumption accounts for approximately 12% of the mix. Currently, the main methods for adding flux to sinter mixes include the following: (1) Traditional batching and mixing: The materials are fed into the batching room according to the mass ratio, and then fed into the mixer for mixing and granulation to form a sintering mixture. This method has the problem that some flux fails to be mineralized, resulting in "white spots" in the sintered ore, which affects the strength of the sintered ore. The high amount of ineffective flux leads to increased flux consumption. (2) Staged flux addition technology: Based on the traditional batching, a part of the flux, accounting for 60%-70% of the total flux, is added in the first mixing, and the remaining flux is added in the second mixing stage. By adjusting the addition method, the calcium ferrite content of the sintered ore is increased by 3%-5% and the flux consumption is reduced by 0.8%-1.2%. This method achieves the goal of reducing flux consumption, but there are quality problems such as reduced mixing uniformity, increased dust risk due to the secondary addition of flux, and difficulty in particle size matching. (3) Flux pretreatment / flux structure optimization technology: By increasing the surface activity of the flux (limestone pre-burning activation, ultra-fine grinding, composite granulation, and replacing limestone with quicklime), the goal of improving flux mineralization efficiency and reducing consumption is achieved. However, there are problems with high pretreatment energy consumption and high costs. (4) Alternative flux development technology: Using metallurgical solid waste (steel slag, dust removal ash, etc.) to replace some traditional fluxes, but there is a risk of enrichment of harmful elements in the solid waste. (5) Intelligent optimization control technology: Through data-driven dynamic and precise control of flux, it can reduce flux consumption and improve the stability rate of sintered ore basicity. However, the investment cost of the detection system equipment is high. Summary of the Invention

[0004] In view of the technical problems in the prior art of reducing flux consumption in the sintering process, such as difficulty in controlling costs and affecting the quality of sintered ore, the present invention provides a sintered ore production process with reduced flux consumption. By adjusting the ingredient ratio and mixing method, not only the flux consumption is reduced, but also the drum index, RDI+3.15mm and sintered ore grade of the sintered ore are improved.

[0005] The technical solutions of the present invention are as follows: A sintered ore production process for reducing flux consumption comprises mixing and granulating a first mixed material and a second mixed material to obtain a third mixed material, distributing the third mixed material, igniting, and sintering the material to obtain sintered ore. The first mixture includes part of iron ore fines, return ore, part of flux and part of fuel, and the part of iron ore fines includes part of fine-grained high-silicon iron ore fines and iron ore concentrate; the second mixture includes remaining iron ore fines, remaining flux and remaining fuel, and the remaining iron ore fines include remaining fine-grained high-silicon iron ore fines and coarse powder; the mass ratio of the fine-grained high-silicon iron ore fines in the first mixture and the second mixture is (12 - 20): (4.4 - 12), the mass ratio of the flux in the first mixture and the second mixture is (5.2 -5.5): (4.8 - 5), and the mass ratio of the fuel in the first mixture and the second mixture is (1.7 - 1.8): (1.6 -1.7); The third mixed material includes, by mass, 24-24.5 parts of fine-grained high-silicon iron ore powder, 15-20 parts of iron ore concentrate, 26-30 parts of coarse powder, 10-20 parts of return ore, 10.1-10.5 parts of flux and 3.3-3.5 parts of fuel; The flux is a mixture of dolomite, quicklime and lime lime, and the mass ratio of dolomite, quicklime and lime lime is 1: (1-1.2): (1-1.2).

[0006] Furthermore, the remaining iron ore fines also include 3-10 parts of iron-containing solid waste recycled resources.

[0007] Iron-containing solid waste recycled resources include iron oxide scale, iron oxide balls, kiln slag, sludge, steel slag powder, dust ash and other iron-containing secondary resources. Adding an appropriate amount of iron-containing solid waste recycled resources can reduce the sintering cost without affecting the sintering quality.

[0008] Furthermore, the first mixture includes part of fine-grained high-silicon iron ore powder, iron ore concentrate, return ore, part of flux and part of fuel; the second mixture includes remaining fine-grained high-silicon iron ore powder, coarse powder, iron-containing solid waste recycled resources, remaining flux and remaining fuel; The mass ratio of fine high-silicon iron ore powder in the first mixture and the second mixture is (16 - 20): (4.4 -8.2), the mass ratio of flux in the first mixture and the second mixture is (5.2 - 5.4): (4.8 - 5), and the mass ratio of fuel in the first mixture and the second mixture is 1.7: (1.6 - 1.7); The third mixed material includes, by mass, 24.2-24.5 parts of fine-grained high-silicon iron ore powder, 15 parts of iron ore concentrate, 26 parts of coarse powder, 17 parts of return ore, 10.1-10.4 parts of flux, 3.3-3.4 parts of fuel and 4 parts of iron-containing solid waste recycled resources; The flux is a mixture of dolomite, quicklime and lime lime, and the mass ratio of dolomite, quicklime and lime lime is 1:1:1.

[0009] Furthermore, the mass ratio of fine high-silicon iron ore powder in the first mixture to the second mixture is 20:4.5, the mass ratio of flux in the first mixture to the second mixture is 5.3:4.8, and the mass ratio of fuel in the first mixture to the second mixture is 1.7:1.6; In terms of mass, the third mixture includes 24.5 parts of high-silicon iron ore powder, 15 parts of iron ore concentrate, 26 parts of coarse powder, 17 parts of return ore, 10.1 parts of flux, 3.3 parts of fuel and 4 parts of iron-containing solid waste recycled resources.

[0010] Furthermore, the composition of the fine-grained high-silicon iron ore powder includes TFe 60% - 62%, SiO2 7% - 12% and Al2O3 0.5% - 2%, and the mass proportion of particles smaller than 1 mm in the fine-grained high-silicon iron ore powder is not less than 50%.

[0011] Furthermore, the composition of the iron ore concentrate includes TFe 61% - 66%, SiO2 3% - 8% and Al2O3 0.5% - 2%, and the proportion of mineral powder with a particle size of less than 1 mm in the iron ore concentrate is not less than 85%.

[0012] Furthermore, the CaO / Fe2O3 molar ratio of the first mixture is 2.0-3.5.

[0013] Furthermore, in fine-grained high-silicon iron ore powder, iron ore concentrate and coarse powder, the proportion of hematite is 30% - 50%, the proportion of limonite is 20% - 50%, and the proportion of magnetite is ≤15%.

[0014] Furthermore, in the weighted calculation of particle size distribution and proportion of fine-grained high-silicon iron ore powder, iron ore concentrate, coarse powder, return ore and iron-containing solid waste recycled resources, the proportion of particle size <1mm is not less than 35%.

[0015] Fine-grained high-silicon iron ore powder, iron ore concentrate, coarse powder, return ore and iron-containing solid waste recycled resources are collectively referred to as iron-containing materials. The specific calculation method for the proportion of particle size <1mm is: the product of the proportion of particle size <1mm in high-silicon iron ore powder in high-silicon iron ore powder and the proportion of high-silicon iron ore powder in iron-containing materials, plus the product of the proportion of particle size <1mm in iron concentrate in iron concentrate and the proportion of iron concentrate in iron-containing materials, plus the product of the proportion of particle size <1mm in coarse powder in coarse powder and the proportion of coarse powder in iron-containing materials, plus the product of the proportion of particle size <1mm in return ore and the proportion of return ore in iron-containing materials, plus the product of the proportion of particle size <1mm in iron-containing solid waste recycled resources in iron-containing solid waste recycled resources and the proportion of iron-containing solid waste recycled resources in iron-containing materials.

[0016] Furthermore, the third mixed material is distributed on a trolley equipped with a bed material, ignited, and sintered to obtain sintered ore; the ignition temperature is 950-1150℃, the ignition time is 1-2 minutes, and the effective exhaust area of the sintering machine is 550-600m 2 , the thickness of the sintering material layer is 800-1000mm.

[0017] The beneficial effects of the present invention are: The present invention provides a sinter production process that reduces flux consumption. The content of each component is controlled during the batching process. During the mixing process, fine-grained high-silicon iron ore powder, flux, and fuel are divided into two appropriate portions, mixed in stages, and then blended. This increases the probability of contact between the fine-grained ore particles (iron ore powder and flux), facilitates the formation of a sintering liquid phase, and produces high-quality sintered ore with low flux consumption. Reduced flux consumption reduces the heat required for mineralization during the sintering process, lowering sintering solids consumption. Furthermore, the sintered ore grade is improved, indirectly leading to higher blast furnace feed grade, lower blast furnace slag ratios, and lower blast furnace fuel ratios. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0019] Figure 1 The present invention is a process flow chart of sinter production for reducing flux consumption. DETAILED DESCRIPTION

[0020] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0021] Those skilled in the art will appreciate that, in the present invention, the sum of a portion of the high-silicon iron ore fines in the first mixture and the remaining high-silicon iron ore fines in the second mixture is the total amount of high-silicon iron ore fines added in the iron ore sintering process. The sum of a portion of the flux in the first mixture and the remaining flux in the second mixture is the total amount of flux added in the iron ore sintering process. The sum of a portion of the fuel in the first mixture and the remaining fuel in the second mixture is the total amount of fuel added in the iron ore sintering process.

[0022] Those skilled in the art will appreciate that the distribution ratio of the flux in the first mixture and the second mixture is determined based on actual composition measurement to ensure that the CaO / Fe2O3 molar ratio of the first mixture is 2.0-3.5.

[0023] Those skilled in the art will understand that iron-containing solid waste recycled resources refer to iron-containing waste or by-products generated during the steel production process. These materials can be recycled and returned to the production process (such as sintering, ironmaking or steelmaking) as raw materials to achieve resource recycling, including iron-containing secondary resources such as iron oxide scale, iron oxide balls, kiln slag, sludge, steel slag powder, and dust removal ash.

[0024] Those skilled in the art will understand that in the sintering process, fine powder generally refers to mineral powder with fine particle size (-1mm accounts for more than 80%), and coarse powder is compared with fine powder, which refers to mineral powder containing large particles and uneven particle size.

[0025] Those skilled in the art will appreciate that, in the present invention, the fuel is coke powder.

[0026] Those skilled in the art will understand that hematite: The main component is ferric oxide, and the crystal structure belongs to the hexagonal system. Its color is usually reddish brown to black, the streak is cherry red, and it has a metallic to semi-metallic luster. Limonite: It is actually a mixture of various minerals. The main component is hydrated ferric oxide. Its crystal structure is not fixed, the color ranges from light yellow to dark brown, the streak is yellowish brown, the luster is dull, and it usually appears as earthy or massive aggregates. Magnetite: The main component is ferroferric oxide, and the crystal structure is an isometric system. It has strong magnetism, is iron black in color, has a black streak, and has a metallic luster. Commercially available high-silicon iron ore powder, iron concentrate, and coarse powder contain hematite, limonite, and magnetite in different proportions.

[0027] Example 1 A sintered ore production process for reducing flux consumption comprises the following steps: Step 1: Ingredients Calculated by mass, the materials used in the production of sintered ore are 24 parts of fine-grained high-silicon iron ore powder, 15 parts of iron concentrate, 26 parts of coarse powder, 4 parts of iron-containing solid waste recycled resources, 17 parts of returned ore, 10.5 parts of flux, and 3.5 parts of fuel; the fine-grained high-silicon iron ore powder is divided into two parts, and the mass ratio of the first mixture to the second mixture is 1:1; the flux is divided into two parts, and the mass ratio of the first mixture to the second mixture is 5.5:5; the fuel is divided into two parts, and the mass ratio of the first mixture to the second mixture is 1.8:1.7. The specific material ratios are shown in Table 1.

[0028] Among them, the mass proportion of particles smaller than 1 mm in the fine-grained high-silicon iron ore powder is not less than 50%, and the composition of the fine-grained high-silicon iron ore powder includes TFe 60% - 62%, SiO27% - 12% and Al2O30.5% - 2%.

[0029] The proportion of mineral powder with a particle size of less than 1 mm in the iron ore concentrate is not less than 85%. The composition of the iron ore concentrate includes TFe 61% - 66%, SiO2 3% - 8% and Al2O3 0.5% - 2%.

[0030] The flux is a mixture of dolomite, quicklime and gray lime, with the mass ratio of dolomite, quicklime and gray lime being 1:1:1. The composition of dolomite includes SiO2 2% - 3%, CaO 30.0% - 30.1%, MgO 19.0% - 19.5% and Al2O3 0.6% - 0.7%. The composition of quicklime includes SiO2 1.8% - 2.0%, CaO 82.0% - 85.0%, MgO 2.0% - 3.0% and Al2O3 0.4% - 0.5%. The composition of limestone includes SiO2 1.8% - 2.0%, CaO 52.0% - 53.0%, MgO 1.0% -1.5% and Al2O3 0.4% - 0.5%.

[0031] Hematite accounts for 30% to 50% of fine-grained high-silicon iron ore fines, iron ore concentrate, and coarse powder, limonite accounts for 20% to 50%, and magnetite accounts for ≤15%. Furthermore, in the weighted calculation of particle size distribution and proportions of fine-grained high-silicon iron ore fines, iron ore concentrate, coarse powder, return ore, and iron-containing solid waste recycled resources, the proportion of particles <1mm is no less than 35%. In the sintering process, this proportion and particle size distribution ensures sufficient reaction during the sintering process, facilitates the formation of a good sintering liquid phase structure, enhances the strength and reducibility of the sintered ore, and thus improves sintering efficiency, output, and finished product quality.

[0032] Step 2: Mixing Part of the high-silicon iron ore powder, iron ore concentrate, return ore, part of the flux and part of the fuel are sent to a primary mixer, mixed for 4 minutes, and mixed evenly to form a first mixture; the remaining fine-grained high-silicon iron ore powder, coarse powder, iron-containing solid waste recycled resources, remaining flux and remaining fuel are sent to a primary mixer, mixed for 4 minutes, and mixed evenly to form a second mixture; the first mixture and the second mixture are sent to a secondary mixer, mixed and granulated for 4 minutes to obtain a third mixture.

[0033] Step 3: Sintering The third mixed material is placed on a trolley equipped with a base material, and ignited and sintered to obtain sintered ore. The ignition temperature is 1040°C, the ignition time is 1.5 minutes, and the effective exhaust area of the sintering machine is 550m 2 The thickness of the sintering material layer is 950mm.

[0034] Example 2 A sintered ore production process for reducing flux consumption comprises the following steps: Step 1: Ingredients Calculated by mass, the materials used in the production of sintered ore are 24.2 parts of fine-grained high-silicon iron ore powder, 15 parts of iron concentrate, 26 parts of coarse powder, 4 parts of iron-containing solid waste recycled resources, 17 parts of returned ore, 10.4 parts of flux, and 3.4 parts of fuel; the fine-grained high-silicon iron ore powder is divided into two parts, and the mass ratio in the first mixture and the second mixture is 8:4.1; the flux is divided into two parts, and the mass ratio in the first mixture and the second mixture is 5.4:5; the fuel is divided into two parts, and the mass ratio in the first mixture and the second mixture is 1:1. The specific material ratios are shown in Table 1.

[0035] Among them, the mass proportion of particles smaller than 1 mm in the fine-grained high-silicon iron ore powder is not less than 50%, and the composition of the high-silicon iron ore powder includes TFe 60% - 62%, SiO27% - 12% and Al2O30.5% - 2%.

[0036] The proportion of mineral powder with a particle size of less than 1 mm in the iron ore concentrate is not less than 85%. The composition of the iron ore concentrate includes TFe 61% - 66%, SiO2 3% - 8% and Al2O3 0.5% - 2%.

[0037] The flux is a mixture of dolomite, quicklime and gray lime, with the mass ratio of dolomite, quicklime and gray lime being 1:1:1. The composition of dolomite includes SiO2 2% - 3%, CaO 30.0% - 30.1%, MgO 19.0% - 19.5% and Al2O3 0.6% - 0.7%. The composition of quicklime includes SiO2 1.8% - 2.0%, CaO 82.0% - 85.0%, MgO 2.0% - 3.0% and Al2O3 0.4% - 0.5%. The composition of limestone includes SiO2 1.8% - 2.0%, CaO 52.0% - 53.0%, MgO 1.0% -1.5% and Al2O3 0.4% - 0.5%.

[0038] Hematite accounts for 30% to 50% of fine-grained high-silicon iron ore fines, iron ore concentrate, and coarse powder, limonite accounts for 20% to 50%, and magnetite accounts for ≤15%. Furthermore, in the weighted calculation of particle size distribution and proportions of fine-grained high-silicon iron ore fines, iron ore concentrate, coarse powder, return ore, and iron-containing solid waste recycled resources, the proportion of particles <1mm is no less than 35%. In the sintering process, this proportion and particle size distribution ensures sufficient reaction during the sintering process, facilitates the formation of a good sintering liquid phase structure, enhances the strength and reducibility of the sintered ore, and thus improves sintering efficiency, output, and finished product quality.

[0039] Step 2: Mixing Part of the fine-grained high-silicon iron ore powder, iron ore concentrate, return ore, part of the flux and part of the fuel are sent to a primary mixer, mixed for 4 minutes, and mixed evenly to form a first mixture; the remaining fine-grained high-silicon iron ore powder, coarse powder, iron-containing solid waste recycled resources, remaining flux and remaining fuel are sent to a primary mixer, mixed for 4 minutes, and mixed evenly to form a second mixture; the first mixture and the second mixture are sent to a secondary mixer, mixed and granulated for 4 minutes to obtain a third mixture.

[0040] Step 3: Sintering The third mixed material is placed on a trolley equipped with a base material, and ignited and sintered to obtain sintered ore. The ignition temperature is 1040°C, the ignition time is 1.5 minutes, and the effective exhaust area of the sintering machine is 550m 2 The thickness of the sintering material layer is 950mm.

[0041] Example 3 A sintered ore production process for reducing flux consumption comprises the following steps: Step 1: Ingredients Calculated by mass, the materials used in the production of sintered ore are 24.4 parts of fine-grained high-silicon iron ore powder, 15 parts of iron concentrate, 26 parts of coarse powder, 4 parts of iron-containing solid waste recycled resources, 17 parts of returned ore, 10.2 parts of flux, and 3.4 parts of fuel; the fine-grained high-silicon iron ore powder is divided into two parts, and the mass ratio of some fine-grained high-silicon iron ore powder in the first mixture and the second mixture is 5:1.1; the flux is divided into two parts, and the mass ratio of the flux in the first mixture and the second mixture is 5.2:5; the fuel is divided into two parts, and the mass ratio of the fuel in the first mixture and the second mixture is 1.7:1.6. The specific material ratios are shown in Table 1.

[0042] Among them, the mass proportion of particles smaller than 1 mm in the fine-grained high-silicon iron ore powder is not less than 50%, and the composition of the high-silicon iron ore powder includes TFe 60% - 62%, SiO27% - 12% and Al2O30.5% - 2%.

[0043] The proportion of mineral powder with a particle size of less than 1 mm in the iron ore concentrate is not less than 85%. The composition of the iron ore concentrate includes TFe 61% - 66%, SiO2 3% - 8% and Al2O3 0.5% - 2%.

[0044] The flux is a mixture of dolomite, quicklime and gray lime, with the mass ratio of dolomite, quicklime and gray lime being 1:1:1. The composition of dolomite includes SiO2 2% - 3%, CaO 30.0% - 30.1%, MgO 19.0% - 19.5% and Al2O3 0.6% - 0.7%. The composition of quicklime includes SiO2 1.8% - 2.0%, CaO 82.0% - 85.0%, MgO 2.0% - 3.0% and Al2O3 0.4% - 0.5%. The composition of limestone includes SiO2 1.8% - 2.0%, CaO 52.0% - 53.0%, MgO 1.0% -1.5% and Al2O3 0.4% - 0.5%.

[0045] Hematite accounts for 30% to 50% of fine-grained high-silicon iron ore fines, iron ore concentrate, and coarse powder, limonite accounts for 20% to 50%, and magnetite accounts for ≤15%. Furthermore, in the weighted calculation of particle size distribution and proportions of fine-grained high-silicon iron ore fines, iron ore concentrate, coarse powder, return ore, and iron-containing solid waste recycled resources, the proportion of particles <1mm is no less than 35%. In the sintering process, this proportion and particle size distribution ensures sufficient reaction during the sintering process, facilitates the formation of a good sintering liquid phase structure, enhances the strength and reducibility of the sintered ore, and thus improves sintering efficiency, output, and finished product quality.

[0046] Step 2: Mixing Part of the fine-grained high-silicon iron ore powder, iron ore concentrate, return ore, part of the flux and part of the fuel are sent to a primary mixer, mixed for 4 minutes, and mixed evenly to form a first mixture; the remaining fine-grained high-silicon iron ore powder, coarse powder, iron-containing solid waste recycled resources, remaining flux and remaining fuel are sent to a primary mixer, mixed for 4 minutes, and mixed evenly to form a second mixture; the first mixture and the second mixture are sent to a secondary mixer, mixed and granulated for 4 minutes to obtain a third mixture.

[0047] Step 3: Sintering The third mixed material is placed on a trolley equipped with a base material, and ignited and sintered to obtain sintered ore. The ignition temperature is 1040°C, the ignition time is 1.5 minutes, and the effective exhaust area of the sintering machine is 550m 2 The thickness of the sintering material layer is 950mm.

[0048] Example 4 A sintered ore production process for reducing flux consumption comprises the following steps: Step 1: Ingredients Calculated by mass, the materials used in the production of sintered ore are 24.5 parts of fine-grained high-silicon iron ore powder, 15 parts of iron concentrate, 26 parts of coarse powder, 4 parts of iron-containing solid waste recycled resources, 17 parts of returned ore, 10.1 parts of flux, and 3.4 parts of fuel; the fine-grained high-silicon iron ore powder is divided into two parts, and the mass ratio of the fine-grained high-silicon iron ore powder in the first mixture and the second mixture is 20:4.5; the flux is divided into two parts, and the mass ratio of the flux in the first mixture and the second mixture is 5.3:4.8; the fuel is divided into two parts, and the mass ratio of the fuel in the first mixture and the second mixture is 1.7:1.6. The specific material ratios are shown in Table 1.

[0049] Among them, the mass proportion of particles smaller than 1 mm in the fine-grained high-silicon iron ore powder is not less than 50%, and the composition of the fine-grained high-silicon iron ore powder includes TFe 60% - 62%, SiO27% - 12% and Al2O30.5% - 2%.

[0050] The proportion of mineral powder with a particle size of less than 1 mm in the iron ore concentrate is not less than 85%. The composition of the iron ore concentrate includes TFe 61% - 66%, SiO2 3% - 8% and Al2O3 0.5% - 2%.

[0051] The flux is a mixture of dolomite, quicklime and gray lime, with the mass ratio of dolomite, quicklime and gray lime being 1:1:1. The composition of dolomite includes SiO2 2% - 3%, CaO 30.0% - 30.1%, MgO 19.0% - 19.5% and Al2O3 0.6% - 0.7%. The composition of quicklime includes SiO2 1.8% - 2.0%, CaO 82.0% - 85.0%, MgO 2.0% - 3.0% and Al2O3 0.4% - 0.5%. The composition of limestone includes SiO2 1.8% - 2.0%, CaO 52.0% - 53.0%, MgO 1.0% -1.5% and Al2O3 0.4% - 0.5%.

[0052] Hematite accounts for 30% to 50% of fine-grained high-silicon iron ore fines, iron ore concentrate, and coarse powder, limonite accounts for 20% to 50%, and magnetite accounts for ≤15%. Furthermore, in the weighted calculation of particle size distribution and proportions of fine-grained high-silicon iron ore fines, iron ore concentrate, coarse powder, return ore, and iron-containing solid waste recycled resources, the proportion of particles <1mm is no less than 35%. In the sintering process, this proportion and particle size distribution ensures sufficient reaction during the sintering process, facilitates the formation of a good sintering liquid phase structure, enhances the strength and reducibility of the sintered ore, and thus improves sintering efficiency, output, and finished product quality.

[0053] Step 2: Mixing Part of the fine-grained high-silicon iron ore powder, iron ore concentrate, return ore, part of the flux and part of the fuel are sent to a primary mixer, mixed for 4 minutes, and mixed evenly to form a first mixture; the remaining fine-grained high-silicon iron ore powder, coarse powder, iron-containing solid waste recycled resources, remaining flux and remaining fuel are sent to a primary mixer, mixed for 4 minutes, and mixed evenly to form a second mixture; the first mixture and the second mixture are sent to a secondary mixer, mixed and granulated for 4 minutes to obtain a third mixture.

[0054] Step 3: Sintering The third mixed material is placed on a trolley equipped with a base material, and ignited and sintered to obtain sintered ore. The ignition temperature is 1040°C, the ignition time is 1.5 minutes, and the effective exhaust area of the sintering machine is 550m 2 The thickness of the sintering material layer is 950mm.

[0055] The difference from Example 1 is that the proportions of the ingredients in step 1 are different, as shown in Table 1.

[0056] Table 1 Material ratio for sinter production

[0057] Comparative Example 1 An iron ore sintering process comprises the following steps: Step 1: Ingredients The materials used in producing sintered ore are 24 parts by mass of fine-grained high-silicon iron ore powder, 15 parts of iron concentrate, 26 parts of coarse powder, 4 parts of iron-containing solid waste recycled resources, 17 parts of returned ore, 10.5 parts of flux, and 3.5 parts of fuel. The material ratios are compared with those of Examples 1-3 in Table 1.

[0058] Among them, the mass proportion of particles smaller than 1 mm in the fine-grained high-silicon iron ore powder is not less than 50%, and the composition of the fine-grained high-silicon iron ore powder includes TFe 60% - 62%, SiO27% - 12%, and Al2O30.5% - 2%.

[0059] The proportion of mineral powder with a particle size of <1mm in the iron ore concentrate is not less than 85%. The composition of the iron ore concentrate includes TFe 61% - 66%, SiO2 3% - 8%, and Al2O3 0.5% - 2%.

[0060] The flux is a mixture of dolomite, quicklime and gray lime, with the mass ratio of dolomite, quicklime and gray lime being 1:1:1. The composition of dolomite includes SiO2 2% - 3%, CaO 30.0% - 30.1%, MgO 19.0% - 19.5% and Al2O3 0.6% - 0.7%. The composition of quicklime includes SiO2 1.8% - 2.0%, CaO 82.0% - 85.0%, MgO 2.0% - 3.0% and Al2O3 0.4% - 0.5%. The composition of limestone includes SiO2 1.8% - 2.0%, CaO 52.0% - 53.0%, MgO 1.0% -1.5% and Al2O3 0.4% - 0.5%.

[0061] In fine-grained high-silicon iron ore powder, iron ore concentrate and coarse powder, hematite accounts for 30% - 50%, limonite accounts for 20% -50%, and magnetite accounts for ≤15%. In addition, in fine-grained high-silicon iron ore powder, iron ore concentrate, coarse powder, return ore and iron-containing solid waste recycled resources, the particle size distribution and proportion are weightedly calculated, and the proportion of particle size <1mm is not less than 35%.

[0062] Step 2: Mixing The above-mentioned parts by mass of fine-grained high-silicon iron ore powder, iron ore concentrate, coarse powder, iron-containing solid waste recycled resources, return ore, flux and fuel are sent to a primary mixer, mixed for 4 minutes, and mixed to form mixture A. Mixture A is sent to a secondary mixer, mixed for 4 minutes, and mixed to form mixture B.

[0063] Step 3: Sintering Mixture B is placed on a trolley with a base material, and ignited and sintered to obtain sintered ore. The ignition temperature is 1040°C, the ignition time is 1.5 minutes, and the effective exhaust area of the sintering machine is 550m2 The thickness of the sintering material layer is 950mm.

[0064] Test Case The sintered ores obtained by sintering Examples 1-3 and Comparative Example 1 were subjected to quality tests. The test indicators included TFe, basicity, drum index, and RDI+3.15 mm. The results are shown in Table 2.

[0065] TFe represents the sum of all iron elements in sintered ore, including various iron oxides and iron in other iron-containing compounds. During the sintering process, iron-containing raw materials are heated, batched, and sintered to enrich and transform the iron, ultimately forming sintered ore with a certain TFe content. A higher TFe content generally indicates a lower impurity content in the sintered ore, providing more iron for blast furnace ironmaking, reducing ironmaking costs and improving production efficiency.

[0066] Basicity refers to the ratio of basic oxides to acidic oxides in sintered ore, typically expressed as the mass ratio of calcium oxide (CaO) to silicon dioxide (SiO2). It is a key indicator of sintered ore quality and has a significant impact on the metallurgical properties of the sintered ore and the blast furnace ironmaking process. Different blast furnace production processes and raw material conditions have different requirements for sintered ore basicity. Generally speaking, the basicity of sintered ore used in modern blast furnaces is typically between 1.8 and 2.2.

[0067] The drum index is an important indicator for measuring the strength of sintered ore or pellets. The higher the drum index, the stronger the sintered ore, making it less likely to break and pulverize during transportation and blast furnace smelting. This ensures air permeability and material column stability within the blast furnace, contributing to improved blast furnace production efficiency and lowered coke ratios. The standard test method employed is to take equal amounts of sintered ore samples from Examples 1-3 and Comparative Example 1, place them in a drum with an inner diameter of 1000 mm and a length of 500 mm, and rotate them at 25 rpm for 4 minutes. After rotation, the sample is removed and sieved, and the mass of the portion above the sieve (greater than 6.3 mm) and the portion below the sieve (less than 6.3 mm) are measured.

[0068] RDI+3.15mm refers to the proportion of sintered ore particles larger than 3.15mm in the low-temperature reduction pulverization index. The higher this index, the greater the sintered ore's ability to maintain its particle size during low-temperature reduction, resulting in less pulverization and a smaller impact on the permeability of the blast furnace charge column.

[0069] Table 2 Sinter quality indicators

[0070] As shown in Table 2, Example 1 and Comparative Example 1 share the same material ratios, but differ in their mixing methods, resulting in differences in the quality of the resulting sintered ore. Compared to Comparative Example 1, Example 1 exhibits improved drum index and RDI+3.15mm, indicating that the multiple mixing methods employed in Example 1 increase liquid phase generation during the sintering process, contributing to improved sintered ore quality.

[0071] Based on Example 1, the ratio of fine-grained high-silicon iron ore powder in the first and second mixtures was adjusted, the flux ratio was reduced, and the fuel ratio was also adjusted accordingly to obtain Examples 2-4.

[0072] Compared with Example 1, the flux ratio and fuel ratio of Example 2 were respectively reduced by 0.1%, and the drum index and RDI+3.15mm indicators decreased slightly, but were still better than those of Comparative Example 1. Compared with Example 1, the flux ratio of Example 3 was reduced by 0.3%, and the fuel ratio was reduced by 0.2%, and the sintered ore grade (TFe) was increased by 0.18%, and the drum index and RDI+3.15mm indicators decreased slightly, but were still better than those of Comparative Example 1. Compared with Example 1, the flux ratio of Example 3 was reduced by 0.4%, and the fuel ratio was reduced by 0.2%, and the sintered ore grade (TFe) was increased by 0.25%, and the sintered ore quality indicators were equivalent to those of Comparative Example 1.

[0073] The present invention starts from the sintering process mechanism and optimizes the batching and mixing methods to achieve the goal of improving the sintered ore grade, drum index and RDI+3.15mm index while reducing the sintering cost.

[0074] Taking Example 4 as an example, compared to Comparative Example 1, the sintering flux ratio was reduced by 0.4%, the sintered ore basicity was reduced by 0.04, the fuel ratio was reduced by 0.2%, and the sintered ore grade was increased by 0.25%. The drum index and RDI+3.15mm indicators were essentially the same. Based on the assumption that sintered ore accounts for 75% of the ferrous material fed to the blast furnace, the overall blast furnace feed grade increased by approximately 0.19%, the fuel ratio was reduced by approximately 0.28 kg / t, and blast furnace output increased by approximately 0.47%.

[0075] Taking Example 4 as an example, compared with Comparative Example 1, its flux ratio is reduced by 0.4%. 2 Based on an annual production of 5.5 million tons of sintered ore, the flux consumption is 170 kg / ton of ore, and the annual flux consumption is about 935,000 tons. The unit price is 100 yuan / ton. The annual benefit brought by reducing the flux ratio by 0.4% is about 374,000 yuan.

[0076] Taking Example 4 as an example, compared with Comparative Example 1, its fuel ratio is reduced by 0.1%. 2Assuming an annual output of 5.5 million tons of sintered ore, fuel consumption is 50 kg / ton of ore, and annual fuel consumption is about 275,000 tons. The unit price is 1,200 yuan / ton. The annual benefit brought by reducing the fuel ratio by 0.1% is about 330,000 yuan.

[0077] Although the present invention has been described in detail with reference to the accompanying drawings and in conjunction with preferred embodiments, the present invention is not limited thereto. Without departing from the spirit and essence of the present invention, persons of ordinary skill in the art may make various equivalent modifications or substitutions to the embodiments of the present invention, and such modifications or substitutions shall be within the scope of the present invention. Any changes or substitutions that can be easily conceived by persons skilled in the art within the technical scope disclosed in the present invention shall be within the scope of protection of the present invention.

Claims

1. A sintered ore production process for reducing flux consumption, characterized in that: The first mixed material and the second mixed material are mixed and granulated to obtain a third mixed material, and the third mixed material is distributed, ignited, and sintered to obtain sintered ore; The first mixture includes part of iron ore powder, return ore, part of flux and part of fuel, and the part of iron ore powder includes part of fine-grained high-silicon iron ore powder and iron ore concentrate; the second mixture includes remaining iron ore powder, remaining flux and remaining fuel, and the remaining iron ore powder includes remaining fine-grained high-silicon iron ore powder and coarse powder; the mass ratio of the fine-grained high-silicon iron ore powder in the first mixture and the second mixture is (12 - 20): (4.4 - 12), the mass ratio of the flux in the first mixture and the second mixture is (5.2 - 5.5): (4.8 - 5), and the mass ratio of the fuel in the first mixture and the second mixture is (1.7 - 1.8): (1.6 - 1.7); The third mixed material includes, by mass, 24-24.5 parts of fine-grained high-silicon iron ore powder, 15-20 parts of iron ore concentrate, 26-30 parts of coarse powder, 10-20 parts of return ore, 10.1-10.5 parts of flux and 3.3-3.5 parts of fuel; The flux is a mixture of dolomite, quicklime and lime lime, and the mass ratio of dolomite, quicklime and lime lime is 1: (1-1.2): (1-1.2).

2. The sintered ore production process for reducing flux consumption according to claim 1, wherein: The remaining iron ore fines also include 3-10 parts of iron-containing solid waste recycled resources.

3. A sintered ore production process for reducing flux consumption according to claim 1 or 2, characterized in that: The first mixture includes part of fine-grained high-silicon iron ore powder, iron ore concentrate, return ore, part of flux and part of fuel; the second mixture includes remaining fine-grained high-silicon iron ore powder, coarse powder, iron-containing solid waste recycled resources, remaining flux and remaining fuel; The mass ratio of fine-grained high-silicon iron ore powder in the first mixture and the second mixture is (16 - 20): (4.4 - 8.2), the mass ratio of flux in the first mixture and the second mixture is (5.2 - 5.4): (4.8 - 5), and the mass ratio of fuel in the first mixture and the second mixture is 1.7: (1.6 - 1.7); The third mixed material includes, by mass, 24.2-24.5 parts of fine-grained high-silicon iron ore powder, 15 parts of iron ore concentrate, 26 parts of coarse powder, 17 parts of return ore, 10.1-10.4 parts of flux, 3.3-3.4 parts of fuel and 4 parts of iron-containing solid waste recycled resources; The flux is a mixture of dolomite, quicklime and lime lime, and the mass ratio of dolomite, quicklime and lime lime is 1:1:

1.

4. A sintered ore production process for reducing flux consumption according to claim 3, characterized in that: The mass ratio of fine high-silicon iron ore powder in the first mixture and the second mixture is 20:4.5, the mass ratio of flux in the first mixture and the second mixture is 5.3:4.8, and the mass ratio of fuel in the first mixture and the second mixture is 1.7:1.6; In terms of mass, the third mixture includes 24.5 parts of fine-grained high-silicon iron ore powder, 15 parts of iron ore concentrate, 26 parts of coarse powder, 17 parts of returned ore, 10.1 parts of flux, 3.3 parts of fuel and 4 parts of iron-containing solid waste recycled resources.

5. The sintered ore production process for reducing flux consumption according to claim 1, wherein: The composition of the fine-grained high-silicon iron ore powder includes TFe 60% - 62%, SiO27% - 12% and Al2O3 0.5% - 2%, and the mass proportion of particles smaller than 1 mm in the fine-grained high-silicon iron ore powder is not less than 50%.

6. The sintered ore production process for reducing flux consumption according to claim 1, wherein: The composition of the iron ore concentrate includes TFe 61% - 66%, SiO2 3% - 8% and Al2O3 0.5% - 2%, and the proportion of mineral powder with a particle size of <1mm in the iron ore concentrate is not less than 85%.

7. The sintered ore production process for reducing flux consumption according to claim 1, wherein: The CaO / Fe2O3 molar ratio of the first mixture is 2.0-3.

5.

8. A sintered ore production process for reducing flux consumption according to claim 1 or 2, characterized in that: In fine-grained high-silicon iron ore powder, iron ore concentrate and coarse powder, hematite accounts for 30% - 50%, limonite accounts for 20% - 50%, and magnetite accounts for ≤15%.

9. A sintered ore production process for reducing flux consumption according to claim 2, characterized in that: In the weighted calculation of particle size distribution and proportion in fine-grained high-silicon iron ore powder, iron ore concentrate, coarse powder, returned ore and iron-containing solid waste recycled resources, the proportion of particle size <1mm is not less than 35%.

10. The sintered ore production process for reducing flux consumption according to claim 1, wherein: The third mixed material is placed on a trolley with a base material, ignited, and sintered to obtain sintered ore. The ignition temperature is 950-1150℃, the ignition time is 1-2 minutes, and the effective exhaust area of the sintering machine is 550-600m 2 , the thickness of the sintering material layer is 800-1000mm.

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