Method for generating metallized block mass through high-temperature reduction of biomass in high-silicon iron ore

Abstract

The invention belongs to the technical field of blast furnace smelting furnace charge preparation, and particularly relates to a method for generating metallized agglomerates through high-temperature reduction of biomass prepared in high-silicon iron ore, which comprises the following steps: S1) drying biomass, bituminous coal and high-silicon iron ore, then screening, and adding into a ball mill for uniform mixing; s2) pressing the uniformly mixed material by using a briquetting machine to form a cylindrical block mass; and S3) carrying out roasting reduction treatment on the block mass. The method has the advantages that the biomass is used as a part of reducing agent to replace traditional pulverized coal, so that the use of fossil fuel is reduced, the energy consumption is reduced, and the reduction of carbon emission is facilitated. According to the method, the reduction efficiency of the high-silicon iron ore is improved by accurately controlling the carbon-oxygen ratio and the biomass ratio. And reducing gas is rapidly generated in the pyrolysis process of the biomass, biomass charcoal is deposited on the surfaces of high-silicon iron ore particles and in pores, a coupling effect is formed, and low-temperature rapid reduction of iron oxide is promoted.

Description

Technical Field

[0001] The invention belongs to the technical field of blast furnace smelting charge preparation, and in particular relates to a method for generating metallized agglomerates by high-temperature reduction of biomass in high-silicon iron ore. Background Art

[0002] Domestic blast furnace smelting primarily uses sintered ore, pelletized ore, and natural lump ore as charge materials. In recent years, companies and researchers have begun to focus on blast furnace smelting technology using metallized charge materials. Metallized charge materials utilize a reducing agent to reduce ore fines to metallic iron, simplifying the process compared to traditional sintering and pelletizing. High-iron metallized charge materials help increase blast furnace output, reduce coke ratios, and minimize flux and slag usage, achieving high efficiency and low-cost blast furnace smelting.

[0003] my country boasts abundant reserves of high-silicon iron ore, exceeding 55 billion tons. However, its SiO2 content is high, with some even exceeding 10%. This results in low slag basicity and high viscosity during blast furnace smelting, poor desulfurization, and high energy consumption. Therefore, the efficient development and utilization of high-silicon iron ore is crucial for reducing dependence on imported ore and alleviating the shortage of iron ore resources.

[0004] At present, researchers mainly conduct research on metallized furnace charges based on traditional high-quality iron ore resources, while research on the combined preparation of metallized furnace charges with high-silicon iron ore and biomass is still in-depth. This study innovatively uses high-silicon iron ore as raw material to improve the utilization rate of iron ore resources and alleviate the problem of scarcity of high-quality iron ore resources. At the same time, biomass and coal are used as reducing agents and energy sources to reduce energy consumption. The pore structure generated by the biomass pyrolysis reaction can inhibit the high-temperature adhesion phenomenon of high-silicon iron ore, and the reducing gases it produces (such as CO and H2) can promote the reduction of iron oxides. Based on the fixed carbon reduction process, biomass charcoal reduces the iron oxides in high-silicon iron ore to metallic iron, realizes the preparation of high-metallization rate agglomerates, optimizes the mineral phase structure, and enhances the application value of high-silicon iron ore in blast furnace smelting. In addition, as a carbon-neutral raw material, the carbon dioxide released during the pyrolysis and reduction of biomass can offset the carbon dioxide absorbed during the growth process, significantly reducing carbon emissions, and providing important support for the efficient utilization of high-silicon iron ore resources and the low-carbon transformation of the steel industry. Summary of the Invention

[0005] To overcome the shortcomings of the prior art, the present invention provides a method for high-temperature reduction of high-silicon iron ore with biomass to produce metallized agglomerates. Using high-silicon iron ore as the raw material, biomass and coal as reducing agents and energy sources, this method achieves efficient, low-carbon, high-temperature reduction of the high-silicon iron ore. The reducing gases and biochar produced by biomass pyrolysis can effectively promote the reduction of high-silicon iron ore, thereby increasing the application of low-quality high-silicon iron ore in blast furnace smelting. Replacing part of the coal with biomass can improve reduction efficiency and reduce reliance on traditional coal energy.

[0006] To achieve the above object, the present invention is implemented through the following technical solutions:

[0007] A method for generating metallized agglomerates by high-temperature reduction of biomass in high-silicon iron ore comprises the following steps:

[0008] S1) drying the biomass, bituminous coal and high-silicon iron ore, sieving them, and adding them to a ball mill for uniform mixing;

[0009] S2) the mixed material is compressed using a briquetting machine to form cylindrical agglomerates;

[0010] S3) The agglomerates are subjected to a calcination reduction treatment.

[0011] The biomass is one of corn cobs, cotton stalks and waste wood chips.

[0012] The drying treatment in S1) is carried out in a drying oven at a drying temperature of 105-110° C. for 2-3 hours.

[0013] After sieving in S1), powder particles with a mesh size of ≤200 are obtained, and 100% of the material processed by the ball mill passes through a sieve with a pore size of 74 μm.

[0014] The mass content of SiO2 in the high silicon iron ore in S1) is greater than 5%.

[0015] In the above S1), the carbon ratio C / O in the material after the biomass, bituminous coal and high-silicon iron ore are uniformly mixed is 0.8-1.2; and the biomass in the material is 20%-60% by mass.

[0016] The diameter of the cylindrical agglomerate is ≤35 mm and the height is ≤20 mm.

[0017] In the above S2), the pressing pressure is 10-20 MPa and the density of the agglomerate is 2.5-3.5 g / cm 3 .

[0018] In the step S3), the temperature of the calcination reduction is 1000-1200° C., and the reduction time is 20-50 min.

[0019] In the above S3), the roasting and reduction equipment is a horizontal vacuum tube furnace, and argon is introduced before pressing as an early protective gas.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] 1. The present invention uses biomass as a partial reducing agent to replace traditional pulverized coal, reducing the use of fossil fuels, lowering energy consumption, and helping to reduce carbon emissions. Biomass is a renewable resource, and using it as a reducing agent helps reduce dependence on non-renewable resources and promote sustainable development.

[0022] 2. This invention optimizes the reduction reaction conditions by precisely controlling the carbon-oxygen ratio and biomass ratio, thereby improving the reduction efficiency of high-silicon iron ore. Furthermore, during the pyrolysis process, the biomass rapidly produces reducing gases such as CO and H2, and deposits biochar on the surface and within the pores of the high-silicon iron ore particles, creating a coupling effect that significantly promotes the low-temperature, rapid reduction of iron oxides. Furthermore, the pyrolysis and gasification of the biomass provides additional heat and reducing agents for the reduction reaction, further improving the reduction efficiency.

[0023] 3. The present invention uses a ball mill to mix biomass and iron concentrate, achieving a fully uniform combination, thereby ensuring a higher iron metallization rate and reducing unnecessary energy consumption. Before heating, argon gas is introduced to remove air, effectively preventing oxygen interference and the occurrence of oxidation reactions, ensuring the smooth progress of the reduction reaction.

[0024] 4. The process design of the present invention can improve the utilization rate of inferior high-silicon iron ore, enhance reaction efficiency, reduce energy consumption, and thus reduce production costs.

[0025] 5. The high-temperature reduction of biomass in the high-silicon iron ore prepared by the present invention generates metallized agglomerates, with a metallization rate of over 55.8%, and up to 88.75%. This provides key theoretical support for the further development of a more efficient, environmentally friendly, and energy-saving metallized agglomerate preparation process, and effectively promotes technological innovation and industrial upgrading in the steel industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a preparation flow chart for high-silicon iron ore containing biomass to generate metallized agglomerates through high-temperature reduction. DETAILED DESCRIPTION

[0027] The present invention will be described in detail below with reference to the accompanying drawings, but it should be noted that the implementation of the present invention is not limited to the following embodiments.

[0028] See Figure 1 A method for generating metallized agglomerates based on high-silicon iron ore with biomass at high temperature reduction comprises the following steps:

[0029] S1) The biomass, bituminous coal, and high-silicon magnetite are dried in a drying oven to remove moisture and prevent it from interfering with subsequent reactions. The drying temperature is 105-110°C for 2-3 hours. The mixture is then sieved to obtain a powder with a mesh size of ≤200. This removes coarse particles and impurities, ensuring uniformity. The sieved material is then added to a ball mill for uniform mixing and sieved to obtain a material that passes 100% through a 74 μm sieve.

[0030] The biomass is selected from corn cobs, cotton stalks, or waste sawdust. The high-silicon iron ore contains greater than 5% SiO2 by mass and also contains Al2O3, CaO, MgO, and TiO2. The biomass, bituminous coal, and high-silicon iron ore are uniformly mixed to achieve a carbon / carbon ratio (C / O) of 0.8 to 1.2, preferably 1. The biomass content of the material is 20% to 60% by mass, preferably 40%.

[0031] S2) The mixed material is pressed using a briquetting machine at a pressing pressure of 10-20 MPa to form cylindrical agglomerates with a diameter of 35 mm and a length of 20 mm. The density of the agglomerates is 2.5-3.5 g / cm 3 In order to improve the density and mechanical strength of the material, ensure the stability of the agglomerate shape during the roasting and reduction process, and make it heat evenly in the furnace and react fully.

[0032] S3) The agglomerates are subjected to a calcination reduction treatment. The calcination reduction equipment is a horizontal vacuum tube furnace, with argon introduced as a protective gas before pressing. The calcination reduction temperature is 1000-1200°C, and the reduction time is 20-50 minutes. In a high-temperature environment, the agglomerates undergo a reduction reaction to form metallized agglomerates, resulting in a product with a high metallization ratio.

[0033] Example 1

[0034] See Figure 1 The method for high-silicon iron ore containing biomass to generate metallized agglomerates by high-temperature reduction comprises the following steps:

[0035] S1: Take 1000g of iron ore concentrate, 300g of biomass (corn cob), and 200g of bituminous coal powder, and mix them according to a C / O ratio of 1 and a biomass ratio of 20%. Pour the mixed materials into a ball mill and mix for 10 minutes to obtain a mixture that 100% passes through a 74μm pore size sieve to ensure material uniformity.

[0036] S2: The mixed materials were pressed using a briquetting machine to form cylindrical lumps with a diameter of 35 mm and a length of 20 mm.

[0037] S3: Place the pressed agglomerates into a horizontal vacuum tube furnace. Before heating, introduce argon into the furnace for 20 minutes to exclude air. Then, heat the furnace to 1200°C at a rate of 7°C / min and keep the temperature for 50 minutes.

[0038] S4: After the roasting and reduction is completed, the furnace is cooled to room temperature to obtain a metallized agglomerate of high silicon iron ore with corn cobs.

[0039] Example 2

[0040] See Figure 1 The method for high-temperature reduction of biomass in high-silicon iron ore to generate metallized agglomerates comprises the following steps:

[0041] S1: Take 1000g of iron ore concentrate, 300g of biomass (corn cob), and 200g of bituminous coal powder, and mix them according to a C / O ratio of 1 and a biomass ratio of 40%. Pour the mixed materials into a ball mill and mix for 10 minutes to obtain a mixture that 100% passes through a 74μm pore size sieve to ensure material uniformity.

[0042] S2: The mixed materials were pressed using a briquetting machine to form cylindrical lumps with a diameter of 35 mm and a length of 20 mm.

[0043] S3: Place the pressed agglomerates into a horizontal vacuum tube furnace. Before heating, introduce argon into the furnace for 20 minutes to exclude air. Then, heat the furnace to 1200°C at a rate of 7°C / min and keep the temperature for 50 minutes.

[0044] S4: After the roasting and reduction is completed, the furnace is cooled to room temperature to obtain a metallized agglomerate of high-silicon iron ore with sawdust.

[0045] Example 3

[0046] See Figure 1 The method for high-temperature reduction of biomass in high-silicon iron ore to generate metallized agglomerates comprises the following steps:

[0047] S1: Take 1000g of iron ore concentrate, 300g of biomass (corn cob), and 200g of bituminous coal powder, and mix them according to a C / O ratio of 1 and a biomass ratio of 60%. Pour the mixed materials into a ball mill and mix for 10 minutes to obtain a mixture that 100% passes through a 74μm pore size sieve to ensure material uniformity.

[0048] S2: The mixed materials were pressed using a briquetting machine to form cylindrical lumps with a diameter of 35 mm and a length of 20 mm.

[0049] S3: Place the pressed agglomerates into a horizontal vacuum tube furnace. Before heating, introduce argon for 20 minutes to exclude air. Then, heat the agglomerates to 1200°C at a rate of 7°C / min and keep the temperature for 50 minutes.

[0050] S4: After the roasting and reduction is completed, the furnace is cooled to room temperature to obtain a metallized agglomerate of high-silicon iron ore and cotton straw.

[0051] Example 4

[0052] See Figure 1 The method for high-temperature reduction of biomass in high-silicon iron ore to generate metallized agglomerates comprises the following steps:

[0053] S1: Take 1000g of iron ore concentrate, 300g of biomass (wood chips), and 200g of bituminous coal powder, and mix them according to a C / O ratio of 1 and a biomass ratio of 20%. Pour the mixed materials into a ball mill and mix for 10 minutes to obtain a mixture that 100% passes through a 74μm pore size sieve to ensure material uniformity.

[0054] S2: The mixed materials were pressed using a briquetting machine to form cylindrical lumps with a diameter of 35 mm and a length of 20 mm.

[0055] S3: Place the pressed agglomerates into a horizontal vacuum tube furnace. Before heating, introduce argon for 20 minutes to exclude air. Then, heat the agglomerates to 1200°C at a rate of 7°C / min and keep the temperature for 50 minutes.

[0056] S4: After the roasting and reduction is completed, the furnace is cooled to room temperature to obtain a metallized agglomerate of high silicon iron ore with corn cobs.

[0057] Example 5

[0058] See Figure 1 The method for high-temperature reduction of biomass in high-silicon iron ore to generate metallized agglomerates comprises the following steps:

[0059] S1: Take 1000g of iron ore concentrate, 300g of biomass (wood chips), and 200g of bituminous coal powder, and mix them according to a C / O ratio of 1 and a biomass ratio of 40%. Pour the mixed materials into a ball mill and mix for 10 minutes to obtain a mixture that 100% passes through a 74μm pore size sieve to ensure material uniformity.

[0060] S2: The mixed materials were pressed using a briquetting machine to form cylindrical lumps with a diameter of 35 mm and a length of 20 mm.

[0061] S3: Place the pressed agglomerates into a horizontal vacuum tube furnace. Before heating, introduce argon for 20 minutes to exclude air. Then, heat the agglomerates to 1200°C at a rate of 7°C / min and keep the temperature for 50 minutes.

[0062] S4: After the roasting and reduction is completed, the furnace is cooled to room temperature to obtain a metallized agglomerate of high-silicon iron ore with sawdust.

[0063] Example 6

[0064] See Figure 1 The method for high-temperature reduction of biomass in high-silicon iron ore to generate metallized agglomerates comprises the following steps:

[0065] S1: Take 1000g of iron ore concentrate, 300g of biomass (wood chips), and 200g of bituminous coal powder, and mix them according to a C / O ratio of 1 and a biomass ratio of 60%. Pour the mixed materials into a ball mill and mix for 10 minutes to obtain a mixture that 100% passes through a 74μm pore size sieve to ensure material uniformity.

[0066] S2: The mixed materials were pressed using a briquetting machine to form cylindrical lumps with a diameter of 35 mm and a length of 20 mm.

[0067] S3: Place the pressed agglomerates into a horizontal vacuum tube furnace. Before heating, introduce argon for 20 minutes to exclude air. Then, heat the agglomerates to 1200°C at a rate of 7°C / min and keep the temperature for 50 minutes.

[0068] S4: After the roasting and reduction is completed, the furnace is cooled to room temperature to obtain a metallized agglomerate of high-silicon iron ore and cotton straw.

[0069] Example 7

[0070] See Figure 1 The method for high-temperature reduction of biomass in high-silicon iron ore to generate metallized agglomerates comprises the following steps:

[0071] S1: Take 1000g of iron ore concentrate, 300g of biomass (cotton straw), and 200g of bituminous coal powder, and mix them according to a C / O ratio of 1 and a biomass ratio of 20%. Pour the mixed materials into a ball mill and mix for 10 minutes to obtain a mixture that 100% passes through a 74μm pore size sieve to ensure material uniformity.

[0072] S2: The mixed materials were pressed using a briquetting machine to form cylindrical lumps with a diameter of 35 mm and a length of 20 mm.

[0073] S3: Place the pressed agglomerates into a horizontal vacuum tube furnace. Before heating, introduce argon for 20 minutes to exclude air. Then, heat the agglomerates to 1200°C at a rate of 7°C / min and keep the temperature for 50 minutes.

[0074] S4: After the roasting and reduction is completed, the furnace is cooled to room temperature to obtain a metallized agglomerate of high silicon iron ore with corn cobs.

[0075] Example 8

[0076] See Figure 1 The method for high-temperature reduction of biomass in high-silicon iron ore to generate metallized agglomerates comprises the following steps:

[0077] S1: Take 1000g of iron ore concentrate, 300g of biomass (cotton straw), and 200g of bituminous coal powder, and mix them according to a C / O ratio of 1 and a biomass ratio of 40%. Pour the mixed materials into a ball mill and mix for 10 minutes to obtain a mixture that 100% passes through a 74μm pore size sieve to ensure material uniformity.

[0078] S2: The mixed materials were pressed using a briquetting machine to form cylindrical lumps with a diameter of 35 mm and a length of 20 mm.

[0079] S3: Place the pressed mass into a horizontal vacuum tube furnace, remove air for 20 minutes before heating in the horizontal vacuum tube furnace, then heat to 1200°C at a rate of 7°C / min and keep warm for 50 minutes.

[0080] S4: After the roasting and reduction is completed, the furnace is cooled to room temperature to obtain a metallized agglomerate of high-silicon iron ore with sawdust.

[0081] Example 9

[0082] See Figure 1 The method for high-temperature reduction of biomass in high-silicon iron ore to generate metallized agglomerates comprises the following steps:

[0083] S1: Take 1000g of iron ore concentrate, 300g of biomass (cotton straw), and 200g of bituminous coal powder, and mix them according to a C / O ratio of 1 and a biomass ratio of 60%. Pour the mixed materials into a ball mill and mix for 10 minutes to obtain a mixture that 100% passes through a 74μm pore size sieve to ensure material uniformity.

[0084] S2: The mixed materials were pressed using a briquetting machine to form cylindrical lumps with a diameter of 35 mm and a length of 20 mm.

[0085] S3: Place the pressed agglomerates into a horizontal vacuum tube furnace. Before heating, introduce argon for 20 minutes to exclude air. Then, heat the agglomerates to 1200°C at a rate of 7°C / min and keep the temperature for 50 minutes.

[0086] S4: After the roasting and reduction is completed, the furnace is cooled to room temperature to obtain a metallized agglomerate of high-silicon iron ore and cotton straw.

[0087] The metallized agglomerates obtained by high-temperature reduction of the biomass in the high-silicon iron ore obtained in Examples 1 to 9 were subjected to performance evaluation index testing. The total iron content was measured by the titanium trichloride reduction potassium dichromate titration method, and the metallic iron content was measured by the ferric chloride decomposition potassium dichromate titration method. The metallization rate was calculated from the metallic iron and total iron contents. The residual carbon was measured according to GB / T 24525-2009 "Determination of Carbon and Sulfur Content of Direct Reduced Iron". The results are as follows:

[0088] Cluster type Total iron / % Metal iron / % Metallization rate / % Residual carbon / % Example 1 81.92 63.13 77.06 0.006 Example 2 87.32 77.50 88.75 0.357 Example 3 78.57 48.44 61.65 <0.004 Example 4 79.33 54.31 68.46 <0.004 Example 5 85.49 71.87 84.07 0.113 Example 6 75.22 41.99 55.82 <0.004 Example 7 80.01 53.81 67.25 <0.004 Example 8 86.29 72.99 84.58 0.077 Example 9 78.21 47.18 60.32 <0.004

[0089] Performance evaluation indicators show that the high-temperature reduction of high-silicon iron ore with biomass using the method of the present invention produces metallized agglomerates. For three biomasses (corn cobs, sawdust, and cotton stalks), the metallization rate of the metal agglomerates is highest when the biomass ratio is 40%. When the biomass ratio is greater than 40%, the metallization rate shows a downward trend. This indicates that appropriately increasing the biomass addition helps improve the reduction effect, and therefore a biomass addition of 40% is preferred.

Claims

1. A method for generating metallized agglomerates by high-temperature reduction of biomass in high-silicon iron ore, characterized in that: The following steps are involved: S1) drying the biomass, bituminous coal and high-silicon iron ore, sieving them, and adding them to a ball mill for uniform mixing; S2) the mixed material is compressed using a briquetting machine to form cylindrical agglomerates; S3) The agglomerates are subjected to a calcination reduction treatment.

2. The method for generating metallized agglomerates by high-temperature reduction of high-silicon iron ore with biomass according to claim 1, characterized in that: The biomass is one of corn cobs, cotton stalks and waste wood chips.

3. The method for generating metallized agglomerates by high-temperature reduction of high-silicon iron ore with biomass according to claim 1, characterized in that: The drying treatment in S1) is carried out in a drying oven at a drying temperature of 105-110° C. for 2-3 hours.

4. The method for generating metallized agglomerates by high-temperature reduction of high-silicon iron ore with biomass according to claim 1, characterized in that: After sieving in S1), powder particles with a mesh size of ≤200 are obtained, and 100% of the material processed by the ball mill passes through a sieve with a pore size of 74 μm.

5. The method for generating metallized agglomerates by high-temperature reduction of high-silicon iron ore with biomass according to claim 1, characterized in that: The mass content of SiO2 in the high silicon iron ore in S1) is greater than 5%.

6. The method for generating metallized agglomerates by high-temperature reduction of high-silicon iron ore with biomass according to claim 1, characterized in that: In the above S1), the carbon ratio C / O in the material after the biomass, bituminous coal and high-silicon iron ore are uniformly mixed is 0.8-1.2; and the biomass in the material is 20%-60% by mass.

7. The method for generating metallized agglomerates by high-temperature reduction of high-silicon iron ore with biomass according to claim 1, characterized in that: The diameter of the cylindrical agglomerate is ≤35 mm and the height is ≤20 mm.

8. The method for generating metallized agglomerates by high-temperature reduction of high-silicon iron ore with biomass according to claim 1, characterized in that: In the above S2), the pressing pressure is 10-20 MPa and the density of the agglomerate is 2.5-3.5 g / cm 3 .

9. The method for generating metallized agglomerates by high-temperature reduction of high-silicon iron ore with biomass according to claim 1, characterized in that: In the step S3), the temperature of the calcination reduction is 1000-1200° C., and the reduction time is 20-50 min.

10. The method for generating metallized agglomerates by high-temperature reduction of high-silicon iron ore with biomass according to claim 1, characterized in that: In the above S3), the roasting and reduction equipment is a horizontal vacuum tube furnace, and argon is introduced before pressing as an early protective gas.

Images