Preparation process method of metallized sintered ore

Abstract

The invention provides a preparation process method of metallized sintered ore, which comprises the following steps: 1, preparing iron ore concentrate, a flux, a binder, a combustion improver, ferrous metallurgy solid waste, pulverized coal and the like according to a set component formula to form a mixed material; 2, adding water, uniformly stirring and mixing, and controlling the water content to be 14 + / -2%; 3, placing and aging the stirred mixture for more than 48 hours, so that the moisture of the raw materials which are non-uniform in dryness and wetness or insufficiently stirred is uniform and consistent through interpenetration, the physical properties of the raw materials are improved, and extrusion molding is facilitated; fourthly, the aged mixed material is pressed and formed through mechanical pressing, and a formed ore green brick is obtained; and 5, stacking the pressed and qualified ore brick blanks on a kiln car, placing the ore brick blanks on the kiln car, and carrying out standing maintenance for 4 + / -1 days so as to evaporate water, so that the formed brick blanks are fully bonded and compact, and the strength of the ore brick is enhanced. The method is low in investment and simple in equipment. And the applicability is high.

Description

Technical Field

[0001] The invention relates to the field of metal smelting and recycling of metallurgical solid waste, and in particular to a preparation process of metallized sintered ore. Background Art

[0002] In the smelting of contemporary steel enterprises, blast furnace ironmaking is the preferred process for many smelting enterprises. Compared with other types of smelting processes, blast furnace ironmaking has more significant advantages in operability, output, labor production efficiency and comprehensive energy consumption. Therefore, blast furnace ironmaking occupies an important position in the field of steel smelting.

[0003] As for the raw materials needed for blast furnace ironmaking, high-basicity sintered ore has been the main raw material for blast furnace ironmaking in my country since the 1980s. In recent decades, iron-containing raw materials account for nearly 70% of the cost of blast furnace ironmaking, sintered ore accounts for more than 70% of blast furnace ironmaking materials, and accounts for more than 10% of the energy consumption per ton of steel, making it the second largest energy consumer in steel production. At present, the general process of sintered ore is mainly: raw material preparation, first mixing, second mixing, material distribution, sintering in sintering machine, ring cooling, finished sintered ore, blast furnace. This process has high requirements for the particle size of raw materials, requiring a particle size of <5mm, and iron-containing raw materials need to be of high grade, less impurities, good strength, and uniform particle size. At the same time, the investment and construction costs and operating costs are high.

[0004] In summary, the prior art has the following problems: the raw materials required for blast furnace ironmaking are small in particle size and high in grade, resulting in high blast furnace ironmaking costs. Summary of the invention

[0005] The invention provides a preparation process of metallized sintered ore to reduce the production cost and economic benefit of enterprises.

[0006] To this end, the present invention proposes a method for preparing metallized sintered ore, comprising the following steps:

[0007] Step 1: Prepare iron ore concentrate, flux, binder, combustion aid, iron and steel metallurgical solid waste, coal powder, etc. according to the set ingredient formula to form a mixed material;

[0008] Step 2: Add water and stir to mix evenly, and control the moisture content to 14±2%;

[0009] Step 3: Place the stirred mixture for aging for more than 48 hours to make the unevenly dry or insufficiently stirred raw materials reach uniform moisture through mutual penetration, improve the physical properties of the raw materials, and facilitate extrusion molding;

[0010] Step 4: Use mechanical pressing to press the aged mixed material into a molded ore brick;

[0011] Step 5: Stack the pressed qualified ore bricks onto the kiln car. The ore bricks are placed on the kiln car for curing for 4 days ± 1 day. The purpose is to evaporate the water, make the formed bricks fully bonded and dense, and enhance the strength of the ore bricks.

[0012] Step 6: The cured ore bricks are transported to the tunnel kiln by kiln cars for drying and roasting. The maximum temperature of the tunnel kiln is controlled at 1000℃±100℃ for roasting;

[0013] Step 7: After roasting, the bricks are taken out of the kiln. To prevent the reduced metal iron from being oxidized, the 600°C ore bricks are cooled when they come out of the tunnel kiln.

[0014] Step 8: Send the roasted ore bricks to the crushing and screening production line for processing. After crushing, the sintered ore with a particle size greater than 40 mm is returned to the crushing system for further crushing. The crushed qualified ore has a particle size of 5 to 40 mm. The qualified ore is sent to the blast furnace for use as sintered ore, and the ore with a particle size less than 5 mm is returned to the raw material end batching system.

[0015] Furthermore, the particle size of the iron-containing raw materials, flux, and iron and steel metallurgical solid waste is less than 30 mm.

[0016] Furthermore, the 600°C ore bricks are water-cooled after leaving the tunnel kiln.

[0017] Furthermore, the 600°C ore bricks leave the tunnel kiln and enter a closed cooling box for nitrogen cooling.

[0018] Furthermore, the high temperature period from heating to 800°C to the maximum kiln temperature and then gradually cooling to 800°C is controlled to be more than 16 hours.

[0019] Further, choose a crushing and screening production line with a single roll crusher or a jaw crusher, with a screen aperture of 40mm and 5mm

[0020] Furthermore, in the first step, the composition formula is set, calculated in percentage as follows: TFe: 55.5±2; FeO: 8.5±1; MgO: 2.35±0.1; Al2O3<2.9; S<0.12; TiO2<0.5; and sintering basicity: 1.8±0.12.

[0021] The raw materials used in the present invention are not limited to iron ore powder, and other iron-containing materials and metallurgical solid waste can be used, which expands the scope of raw material selection and reduces the requirements for raw material selection. Through compression molding, various raw materials can be used, the raw materials have strong adaptability, and the cost is reduced.

[0022] In addition, compared with the sintering machine, the invention has low investment and simple equipment. It has strong applicability and can be used in brick kilns for firing various building materials, plus a set of crushing equipment. Moreover, the traditional sintering process only uses mineral powder below 3mm, while the process of the invention can use mineral powder or raw materials of 5-10mm. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a flow chart of the working principle of the present invention. DETAILED DESCRIPTION

[0024] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, the present invention is now described.

[0025] The present invention provides a method for preparing a metallized sintered ore, as follows: Figure 1 As shown, the process is as follows:

[0026] Step 1: Prepare the iron-containing raw materials (iron concentrate), flux, binder, combustion aid, iron and steel metallurgical solid waste (metallurgical coke powder, steelmaking primary dust removal ash, blast furnace gas ash, etc.), coal powder, etc. according to the test components. The technical requirements of the raw materials after mixing are detailed in Table 1.

[0027] Table 1: Technical requirements for mixtures

[0028]

[0029] Note: Other ingredients meet the quality standards of ore procurement, and the particle size of iron-containing raw materials, flux, and steel solid waste can be less than 5mm. It is more suitable for materials of wider particle sizes than traditional processes.

[0030] Step 2: Add water and stir to mix evenly. The moisture content should be controlled at 14±2%. No dust will be generated during the mixing process and the material will not be sticky when it is put down.

[0031] The third step: place the stirred materials for aging for more than 48 hours, in order to loosen the raw material particles, make the mud loose, homogenize the water, digest the free CaO and MgO, reduce the water on the surface of the particles from penetrating into the interior of the particles, make the raw materials with uneven dryness or insufficient stirring reach uniform water content through mutual penetration, improve the physical properties of the raw materials, and facilitate extrusion molding.

[0032] Step 4: Use mechanical pressing to form. The mechanical pressing equipment used in the present invention is an automatic brick press and an automatic hydraulic press.

[0033] Step 5: The automatic stacker stacks the qualified pressed ore bricks onto the kiln car. The ore bricks are placed on the kiln car for curing for 4 days ± 1 day. The purpose is to evaporate the moisture, make the formed ore bricks fully bonded and dense, and enhance the strength of the ore bricks.

[0034] Step 6: The cured ore bricks are transported to the tunnel kiln by kiln cars for drying and roasting. The maximum temperature of the tunnel kiln is controlled between 1000℃±200℃ for roasting. The temperature is raised to 800℃, then to the highest kiln temperature, and then gradually cooled to 800℃. The high temperature period is controlled to be more than 16 hours.

[0035] Step 7: After roasting, the bricks are discharged from the kiln. To prevent the reduced metal iron from being oxidized, the 600°C bricks are cooled by water after leaving the tunnel kiln, or cooled by nitrogen in a closed cooling box. The cooling method uses normal temperature cooling water or normal temperature nitrogen.

[0036] Step 8: After the bricks leave the kiln, they are sent to the crushing and screening production line for processing. You can choose a single-roll crusher or a jaw crusher. The screen aperture is 40mm and 5mm. The sintered ore larger than 40mm is returned to the crushing system for further crushing. The crushed qualified ore particle size is 5-40mm. The qualified ore is sent to the blast furnace as sintered ore, and the ore smaller than 5mm is returned to the raw material end batching system.

[0037] Implementation 1: The present invention uses iron ore concentrate (powder) ash as raw material, limestone, dolomite, quicklime, light burning as flux, coke powder or coal powder as auxiliary materials. The specific raw and auxiliary materials are shown in Table 2:

[0038] Table 2: Ingredients list of high basicity sinter

[0039]

[0040] Manufacturing method: 1. According to the above, various raw and auxiliary materials are loaded into the corresponding silos by a forklift, and the mixed materials enter the mixer according to the ingredient list in Table 1. After adding water (the amount of water is linked to the amount of raw and auxiliary materials, the amount of water is controlled at 8%-10%, and the maximum does not exceed 15%), it enters the aging bin, ages for more than 48 hours, and enters the mechanical pressing molding. The mechanical pressing molding pressure is maintained at 10 tons-50 tons, and the pressure is maintained for 0.5-5S. The present invention can obtain the initial strength of sintered ores of different hardness by adjusting the pressing pressure. As the pressure increases, the hardness of the sintered ores also increases; the present invention can adjust the density and strength of the sintered ore block by changing the pressure to meet the needs of blast furnace smelting. The present application can obtain pellets or sintered ores of different shapes by changing the shape of the mechanical pressing mold to meet the needs of different production conditions. For example, it can be a sphere or an ellipsoid, or blocks of various shapes.

[0041] 2. The formed products are transported to the curing site for curing for 4 days, and then sent into the tunnel kiln for stacking and roasting. The tunnel kiln is controlled at a maximum temperature of 1000°C for roasting, and the temperature is raised to 800°C, then to the highest kiln temperature, and then gradually cooled to 800°C. The high-temperature section time is controlled to be more than 16 hours, for example, 17 hours. (With the increase of roasting temperature, the strength of the sintered ore gradually increases, which is inherently manifested in the gradual oxidation of Fe3O4 into Fe2O3 grains. The Fe2O3 grains grow and grow, and then they are interconnected into a whole for consolidation, so the sintering strength is improved. At the same time, the high temperature of 1000°C will reduce the zinc in the material to gaseous zinc (the boiling point of zinc is 907°C). As the combustion flue gas rises, it condenses and re-oxidizes when it reaches a lower temperature (the melting point of zinc is 419.53°C). The zinc oxide fine particles formed by re-oxidation are attached to the rising dust and flue gas and are taken out of the furnace. Reach Eliminating zinc in the material reduces the impact of zinc in the product on blast furnace production. (High zinc will form nodules in the blast furnace, causing suspended materials and disrupting the smooth operation of the blast furnace. At the same time, Zn will react with the gas in the furnace at high temperatures to form Zn oxides or sulfides. These compounds will cause corrosion of metal parts of the furnace top equipment under certain conditions, block the top distribution system, affect the uniformity of the blast furnace distribution, and thus affect the stable operation of the blast furnace and the smelting efficiency.) The time is controlled to be more than 16 hours to ensure that Fe2O3 is fully oxidized into grains and the strength of the sintered ore is guaranteed.

[0042] 3. After the bricks leave the kiln, they are sent to the crushing and screening production line for processing. You can choose a jaw crusher or a single roller crusher screening production line. The screen mesh diameter is 4mm. Sintered ore larger than 40mm needs to be further crushed. The crushed qualified ore particle size is 5-40mm. The qualified ore is sent to the blast furnace for smelting, and the ore smaller than 5mm is returned to the raw material end for further batching.

[0043] 4. By using the qualified metallized sintered ore in a blast furnace, the sintered ore produced by the present invention and the sintered ore produced by the traditional process are respectively smelted in a blast furnace at a ratio of 1:1. The chemical composition of the produced sintered ore is shown in Table 3, and there is no obvious fluctuation in blast furnace production.

[0044] Table 3, sintered ore analysis composition produced by Implementation Plan 1

[0045]

[0046] Note: The present invention has no special restrictions on the type of the iron concentrate, such as domestic magnetite, hematite (red ore), siderite, limonite, hematite, imported ore powder (such as Australia, Brazil, etc.), iron and steel metallurgical solid waste (metallurgical coke powder, steelmaking primary dust ash, blast furnace gas ash, etc.) One or more of the iron concentrates can be used to meet the needs of blast furnace smelting effective ingredients.

[0047] Embodiment 2: The present invention uses iron ore concentrate (powder) as raw material, limestone, dolomite, quicklime, light burning as flux, coke powder or coal powder as auxiliary material, as shown in Table 4

[0048] Table 4: High basicity sintered ore ingredient list

[0049]

[0050]

[0051] Manufacturing method: 1. According to the above, various raw and auxiliary materials are loaded into the corresponding silos by a forklift, and the mixed materials enter the mixer according to the ingredient list in Table 1. After adding water (the amount of water is linked to the amount of raw and auxiliary materials, the amount of water is controlled at 8%-10%, and the maximum does not exceed 15%), it enters the aging bin, ages for more than 48 hours, and enters the mechanical pressing molding. The mechanical pressing molding pressure is maintained at 10 tons-50 tons, and the pressure is maintained for 0.5-5S. The present invention can obtain the initial strength of sintered ores of different hardness by adjusting the pressing pressure. As the pressure increases, the hardness of the sintered ores also increases; the present invention can adjust the density and strength of the sintered ore block by changing the pressure to meet the needs of blast furnace smelting. The present application can obtain pellets or sintered ores of different shapes by changing the shape of the mechanical pressing mold to meet the needs of different production conditions. For example, it can be a sphere or an ellipsoid, or blocks of various shapes.

[0052] 2. The formed products are transported to the curing site for curing for 4 days, and then sent into the tunnel kiln for stacking and roasting. The highest temperature of the tunnel kiln is controlled at 1000℃ for roasting, and the temperature is raised to 800℃, then gradually cooled to the highest temperature of the kiln and then gradually cooled to 800℃. The high temperature section time is controlled to be more than 16 hours.

[0053] 3. After the bricks leave the kiln, they are sent to the crushing and screening production line for processing. You can choose a jaw crusher or a single roller crusher screening production line. The screen mesh size is 40mm and 5mm. Sintered ore larger than 40mm needs to be further crushed. The crushed qualified ore particle size is 5-40mm. The qualified ore is sent to the blast furnace for smelting, and the ore smaller than 5mm is returned to the raw material end for further batching.

[0054] 4. By using the qualified metallized sintered ore in a blast furnace, the sintered ore produced by the present invention and the sintered ore produced by the traditional process are respectively smelted in a blast furnace at a ratio of 1:1. The chemical composition of the produced sintered ore is shown in Table 5, and there is no obvious fluctuation in blast furnace production.

[0055] Table 5. Chemical composition of sintered ore produced in Implementation Plan 2

[0056]

[0057] Note: The present invention has no special restrictions on the type of the iron concentrate, such as domestic magnetite, hematite (red ore), siderite, limonite, hematite, imported ore powder (such as Australia, Brazil, etc.), iron and steel metallurgical solid waste (metallurgical coke powder, steelmaking primary dust ash, blast furnace gas ash, etc.) One or more of the iron concentrates can be used to meet the needs of blast furnace smelting effective ingredients.

[0058] Embodiment 3: The present invention uses iron ore concentrate (powder) as raw material, limestone, dolomite, quicklime, light burning as flux, coke powder or coal powder as auxiliary material, see Table 6 for details

[0059] Table 6: High basicity sintered ore ingredient list

[0060]

[0061] Manufacturing method: 1. According to the above, various raw and auxiliary materials are loaded into the corresponding silo by a forklift, and the mixed materials enter the mixer according to the ingredient list in Table 1. After adding water (the amount of water is linked to the amount of raw and auxiliary materials, the amount of water is controlled at 8%-10%, and the maximum does not exceed 15%), it enters the aging warehouse, ages for more than 48 hours, and enters the mechanical pressing molding. The mechanical pressing molding pressure is maintained at 10 tons-50 tons, for example, 30 tons, and the pressure is maintained for 0.5-5S, for example, 2S. The present invention can obtain the initial strength of sintered ores of different hardness by adjusting the pressing pressure, and the hardness of the sintered ores increases with the increase of pressure; the present invention can adjust the density and strength of the sintered ore block by the change of pressure to meet the needs of blast furnace smelting. The present application can obtain pellets or sintered ores of different shapes by changing the shape of the mechanical pressing mold to meet the needs of different production conditions. For example, it can be a sphere or an ellipsoid, or blocks of various shapes.

[0062] 2. The formed products are transported to the curing site for curing for 4 days, and then sent into the tunnel kiln for stacking and roasting. The highest temperature of the tunnel kiln is controlled at 1000℃ for roasting, and the temperature is raised to 800℃, then gradually cooled to the highest temperature of the kiln and then gradually cooled to 800℃. The high temperature section time is controlled to be more than 16 hours.

[0063] 3. After the bricks leave the kiln, they are sent to the crushing and screening production line for processing. You can choose a jaw crusher or a single roller crusher screening production line. The screen mesh size is 40mm and 5mm. Sintered ore larger than 40mm needs to be further crushed. The crushed qualified ore particle size is 5-40mm. The qualified ore is sent to the blast furnace for smelting, and the ore smaller than 5mm is returned to the raw material end for further batching.

[0064] 4. By using the qualified metallized sintered ore in a blast furnace, the sintered ore produced by the present invention and the sintered ore produced by the traditional process are respectively smelted in a blast furnace at a ratio of 1:1. The chemical composition of the produced sintered ore is shown in Table 7, and there is no obvious fluctuation in blast furnace production.

[0065] Table 7. Chemical composition of sintered ore produced in Implementation Plan 3

[0066]

[0067] Note: The present invention has no special restrictions on the type of the iron concentrate, such as domestic magnetite, hematite (red ore), siderite, limonite, hematite, imported ore powder (such as Australia, Brazil, etc.), iron and steel metallurgical solid waste (metallurgical coke powder, steelmaking primary dust ash, blast furnace gas ash, etc.) One or more of the iron concentrates can be used to meet the needs of blast furnace smelting effective ingredients.

[0068] The above description is only an illustrative embodiment of the present invention and is not intended to limit the scope of the present invention. The components of the present invention can be combined with each other without conflict, and any equivalent changes and modifications made by any technician in the field without departing from the concept and principle of the present invention should fall within the scope of protection of the present invention.

Claims

1. A process for preparing metallized sintered ore, characterized in that: The preparation process of the metallized sintered ore comprises the following steps: Step 1: Prepare iron ore concentrate, flux, binder, combustion aid, iron and steel metallurgical solid waste, coal powder, etc. according to the set ingredient formula to form a mixed material; Step 2: Add water and stir to mix evenly, and control the moisture content to 14±2%; Step 3: Place the stirred mixture for aging for more than 48 hours to make the unevenly dry or insufficiently stirred raw materials reach uniform moisture through mutual penetration, improve the physical properties of the raw materials, and facilitate extrusion molding; Step 4: Use mechanical pressing to press the aged mixed material into a molded ore brick; Step 5: Stack the pressed qualified ore bricks onto the kiln car. The ore bricks are placed on the kiln car for curing for 4 days ± 1 day. The purpose is to evaporate the water, make the formed bricks fully bonded and dense, and enhance the strength of the ore bricks. Step 6: The cured ore bricks are transported to the tunnel kiln by kiln cars for drying and roasting. The maximum temperature of the tunnel kiln is controlled at 1000℃±200℃ for roasting; Step 7: After roasting, the bricks are taken out of the kiln. To prevent the reduced metal iron from being oxidized, the 600°C ore bricks are cooled when they come out of the tunnel kiln. Step 8: Send the roasted ore bricks to the crushing and screening production line for processing. After crushing, the sintered ore with a particle size greater than 40 mm is returned to the crushing system for further crushing. The crushed qualified ore has a particle size of 5 to 40 mm. The qualified ore is sent to the blast furnace for use as sintered ore, and the ore with a particle size less than 5 mm is returned to the raw material end batching system.

2. The method for preparing metallized sintered ore according to claim 1, characterized in that: The particle size of iron-containing raw materials, flux, and iron and steel metallurgical solid waste is <30mm.

3. The method for preparing metallized sintered ore according to claim 1, characterized in that: The 600℃ ore bricks are water-cooled after leaving the tunnel kiln.

4. The method for preparing metallized sintered ore according to claim 1, characterized in that: The 600℃ ore bricks leave the tunnel kiln and enter a closed cooling box for nitrogen cooling.

5. The method for preparing metallized sintered ore according to claim 1, characterized in that: The high temperature period from heating to 800°C to the highest kiln temperature and then gradually cooling to 800°C is controlled to be more than 16 hours.

6. The method for preparing metallized sintered ore according to claim 1, characterized in that: Choose a crushing and screening production line with a single roll crusher or a jaw crusher, with a screen aperture of 40mm and 5mm.

7. The method for preparing metallized sintered ore according to claim 1, characterized in that: In the first step, the composition formula was set, calculated in percentage as follows: TFe: 55.5 ± 2; FeO: 8.5 ± 1; MgO: 2.35±0.1; Al2O3<2.9; S<0.12; TiO2<0.5; sintering basicity: 1.8±0.12.

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