A method for reducing low-temperature reduction disintegration rate of vanadium-titanium magnetite gas-based shaft furnace smelting

Abstract

This invention provides a method for reducing the pulverization rate of low-temperature reduction in vanadium-titanium magnetite gas-based vertical shaft furnace smelting. In this method, the quality of the reducing gas in the gas-based vertical shaft furnace is maintained, including the total H2+CO content and the H2 / CO ratio. The oxidation degree of the reducing gas is adjusted by replacing N2 in the reducing gas with 2-8% CO2 gas. The amount of CO2 gas mixed in is as follows, based on the H2 / CO ratio: when H2 / CO = 2-4 (volume fraction), the amount of CO2 mixed in is 6-8% (volume fraction); when H2 / CO = 4-6 (volume fraction), the amount of CO2 mixed in is 4-6% (volume fraction); when H2 / CO = 6-8 (volume fraction), the amount of CO2 mixed in is 3-5% (volume fraction); and when H2 / CO = 8-10 (volume fraction), the amount of CO2 mixed in is 2-4% (volume fraction). By adjusting the oxidation degree of the reducing gas in gas-based vertical shaft furnace smelting, the low-temperature reduction pulverization rate of vanadium-titanium magnetite oxide pellets was successfully reduced, meeting the requirements of mainstream international gas-based vertical shaft furnace technology.

Description

Technical Field

[0001] This invention relates to the field of vanadium-titanium magnetite gas-based vertical shaft furnace smelting, and specifically to a method for reducing the pulverization rate of low-temperature reduction in vanadium-titanium magnetite gas-based vertical shaft furnace smelting. Background Technology

[0002] Vanadium-titanium magnetite is a composite iron ore primarily composed of iron, titanium, and vanadium, possessing extremely high comprehensive utilization value. As an important iron ore resource in my country, non-blast furnace smelting of vanadium-titanium magnetite is receiving increasing attention. The gas-based shaft furnace-electric furnace smelting process is currently the most mature and widely used non-blast furnace smelting technology. This process can utilize large quantities of clean, hydrogen-rich gas and green electricity to achieve clean and efficient metallurgical separation of vanadium-titanium magnetite, meeting current carbon reduction requirements. Simultaneously, it avoids the use of coke resources required in blast furnace processes, eliminating sintering and coking processes, significantly reducing environmental pollution and environmental pressure, and demonstrating sustainable development capabilities.

[0003] Gas-based shaft furnaces are used to produce vanadium-titanium magnetite metallized pellets for subsequent electric arc furnace (EAF) smelting. However, during the reduction of vanadium-titanium magnetite using reducing gases such as H2 and CO in the gas-based shaft furnace, the vanadium-titanium magnetite pellets undergo severe reduction pulverization at low temperatures (500-900℃). The pulverized powder clogs the voids between the charge particles, affecting the permeability of the charge and the distribution of the reducing gas flow. Only by ensuring good permeability of the gas-based shaft furnace pellet charge during the reduction process can the smooth operation of the gas-based shaft furnace be guaranteed. Therefore, maintaining a low pulverization rate of pellets during the reduction process in the gas-based shaft furnace is one of the key issues in the gas-based shaft furnace-EAF smelting process for vanadium-titanium magnetite. Summary of the Invention

[0004] To address the problem of high pulverization rate of hydrogen-rich gas in the low-temperature reduction process of vanadium-titanium magnetite gas-based vertical shaft furnace, this invention proposes a method to reduce the pulverization rate during low-temperature reduction in vanadium-titanium magnetite gas-based vertical shaft furnace smelting. This method can suppress the pulverization problem of vanadium-titanium pellets during low-temperature reduction in the gas-based vertical shaft furnace, thereby reducing the pulverization rate of vanadium-titanium magnetite during low-temperature reduction and enabling existing vanadium-titanium magnetite oxide pellets to meet the furnace feeding requirements of the gas-based vertical shaft furnace.

[0005] To achieve the above objectives, the present invention provides a method for reducing the pulverization rate of low-temperature reduction in vanadium-titanium magnetite gas-based vertical shaft furnace smelting, comprising the following steps:

[0006] In a gas-based vertical shaft furnace, maintain the quality of the reducing gas, including the total H2+CO content and the H2 / CO ratio;

[0007] The oxidation degree of the reducing gas is adjusted by replacing N2 in the reducing gas with 2-8% CO2 gas.

[0008] As a further aspect of the present invention, adjusting the oxidation degree of the reducing gas includes mixing CO2 gas into the reducing gas to control the redox properties of the gas. The amount of CO2 gas mixed in is adjusted according to the H2 / CO ratio in the reducing gas to ensure that the mass of the reducing gas remains unchanged.

[0009] As a further aspect of the present invention, in a gas-based vertical shaft furnace, the oxidation degree of the reducing gas is adjusted to reduce the low-temperature reduction pulverization rate of vanadium-titanium magnetite oxide pellets, so that the vanadium-titanium pellets meet the feed standards of the Hill process (HYL) vertical shaft furnace. The composition of the vanadium-titanium magnetite oxide pellets includes:

[0010] TFe=53.0–58.0 wt%, TiO2=8.0–15.0 wt%, SiO2=2.0–6.0 wt%, MgO=1.0–3.0 wt%, Al2O3=2.0–5.0 wt%.

[0011] As a further aspect of the present invention, a low-temperature reduction process is carried out in a reduction furnace, wherein the effective component of the reducing gas, H2 / CO, within the range of 2-10, meets the international mainstream gas-based vertical shaft furnace technical requirements for a low-temperature reduction pulverization rate LTD+6.3>80% and an undamaged rate UBI>90%.

[0012] As a further aspect of the present invention, the amount of CO2 gas mixed in, based on the H2 / CO ratio, is as follows:

[0013] When H2 / CO = 2-4 (volume fraction), the amount of CO2 mixed in is 6-8% (volume fraction).

[0014] When H2 / CO = 4-6 (volume fraction), the amount of CO2 mixed in is 4-6% (volume fraction).

[0015] When H2 / CO = 6-8 (volume fraction), the amount of CO2 mixed in is 3-5% (volume fraction).

[0016] When H2 / CO = 8-10 (volume fraction), the amount of CO2 mixed in is 2-4% (volume fraction).

[0017] As a further aspect of the present invention, the method for reducing the pulverization rate of vanadium-titanium magnetite gas-based vertical shaft furnace smelting at low temperatures includes the following steps in the low-temperature reduction pulverization test standard:

[0018] The test temperature was 500℃. After drying the pellets in a drying oven for 4 hours, 500 g ± 1 g of oxidized pellets were weighed and the total number of pellets was counted. Then the pellets were loaded into the reaction tube.

[0019] The reaction tube is placed in the reduction furnace, and the reduction furnace begins to heat up. After the furnace charge temperature rises to 200°C, nitrogen gas is introduced at a rate of 5 L / min, and the temperature continues to rise under nitrogen protection.

[0020] After the furnace charge temperature is raised to 500℃ and stabilized, reducing gas is introduced at 15 L / min for 2 h. After the reduction experiment is completed, the reducing gas is turned off, nitrogen is introduced at 8 L / min, the reaction tube is removed from the furnace and cooled to room temperature.

[0021] After reduction, the furnace charge was removed, weighed, and placed in a rotating drum. It was rotated 300 times at 18 r / min. After removal, it was passed through 6.3 mm and 3.2 mm round-hole sieves. The number of intact pellets was then counted, and the low-temperature pulverization index (LTD) was calculated. +6.3 ) and undamaged rate UBI.

[0022] As a further aspect of the present invention, the low-temperature pulverization index (LTD) +6.3 The breakage rate (UBI) and undamaged rate (UBI) are calculated using the following formulas:

[0023] LTD +6.3 = (m1 / m0) × 100

[0024] UBI = (n2 / n1) × 100

[0025] Where m0 is the original weight of the sample (g); m1 is the mass of the portion remaining on the sieve after sieving with a 6.3 mm sieve (g); n1 is the initial number of pellets; and n2 is the final number of unbroken pellets.

[0026] The present invention discloses a method for reducing the low-temperature reduction pulverization rate of vanadium-titanium magnetite smelting in a gas-based vertical shaft furnace. By adjusting the oxidation degree of the reducing gas in the gas-based vertical shaft furnace smelting process, the low-temperature reduction pulverization rate of vanadium-titanium magnetite oxide pellets is successfully reduced, meeting the requirements of mainstream international gas-based vertical shaft furnace technology. This method is expected to improve the efficiency and yield of the vanadium-titanium magnetite smelting process, thus having broad application prospects in industrial production.

[0027] Compared with existing technologies, the method for reducing the pulverization rate of low-temperature reduction in vanadium-titanium magnetite gas-based vertical shaft furnace smelting proposed in this invention has the following beneficial effects:

[0028] 1. Improved Smelting Efficiency: The method of this invention effectively reduces the low-temperature reduction pulverization rate of vanadium-titanium magnetite oxide pellets by adjusting the oxidation degree of the reducing gas, thereby improving the efficiency of the smelting process. A lower pulverization rate means that more oxide pellets can remain intact during the low-temperature reduction process, reducing losses during smelting.

[0029] 2. Meets International Requirements: The method of this invention enables vanadium-titanium magnetite smelted in a gas-based shaft furnace to meet the requirements of mainstream international gas-based shaft furnace technology, particularly regarding the low-temperature reduction pulverization rate and the rate of unbroken ore. This means that the production process conforms to international standards, contributing to improved product quality and enhanced market competitiveness.

[0030] 3. No change in gas quality: The method of this invention, while meeting international requirements, does not change the total mass of the reducing gas or the ratio of hydrogen to carbon monoxide. This ensures that while reducing the pulverization rate, the quality and properties of the reducing gas required for the smelting process are still maintained.

[0031] 4. Broad Application Prospects: The method of this invention is expected to have broad application prospects in the field of vanadium-titanium magnetite smelting. It can be applied to gas-based shaft furnace technology, such as the Hill process (HYL) shaft furnace, but may also be applicable to other smelting methods to improve the efficiency and output of the smelting process.

[0032] 5. Resource Conservation: By reducing the pulverization rate, this invention helps reduce raw material waste and improve resource utilization efficiency. This is of great significance for sustainable production and environmental protection.

[0033] In summary, the method of the present invention reduces the low-temperature reduction pulverization rate in the vanadium-titanium magnetite gas-based vertical shaft furnace smelting process by optimizing the oxidation degree of the reducing gas, thereby improving smelting efficiency, meeting international requirements, and having broad application prospects, and is expected to bring multiple economic and environmental benefits.

[0034] These or other aspects of this application will become more apparent from the following description of embodiments. It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only, and are not intended to limit the application. Detailed Implementation

[0035] The present application will be further described below with reference to specific embodiments. It should be noted that, without conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0036] To make the objectives, technical solutions, and advantages of this invention clearer, the embodiments of this invention are further described in detail below with reference to specific examples. It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit this application.

[0037] It should be noted that all uses of the terms "first" and "second" in the embodiments of the present invention are for the purpose of distinguishing two different entities or different parameters with the same name. Therefore, "first" and "second" are merely for convenience of expression and should not be construed as limiting the embodiments of the present invention. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion, such as other steps or units inherent in a process, method, apparatus, product, or device that includes a series of steps or units.

[0038] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the embodiments of this application. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0039] The following will describe in detail some embodiments of this application. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0040] During the reduction of vanadium-titanium magnetite using reducing gases such as H2 and CO in a gas-based shaft furnace, the vanadium-titanium magnetite pellets undergo severe reduction pulverization at low temperatures (500-900℃). The pulverized powder clogs the voids between the charge particles, affecting the permeability of the charge and the distribution of the reducing gas flow. Only by ensuring good permeability of the gas-based shaft furnace pellet charge during the reduction process can the smooth operation of the furnace be guaranteed. Therefore, maintaining a low pulverization rate of the pellets during the reduction process in a gas-based shaft furnace is one of the key issues in the gas-based shaft furnace-electric furnace smelting process for processing vanadium-titanium magnetite.

[0041] To address the above problems, this invention provides a method for reducing the pulverization rate of low-temperature reduction in vanadium-titanium magnetite gas-based vertical shaft furnace smelting, comprising the following steps:

[0042] In a gas-based vertical shaft furnace, maintain the quality of the reducing gas, including the total H2+CO content and the H2 / CO ratio;

[0043] The oxidation degree of the reducing gas is adjusted by replacing N2 in the reducing gas with 2-8% CO2 gas.

[0044] The process of adjusting the oxidation degree of the reducing gas includes mixing CO2 gas into the reducing gas to control the redox properties of the gas. The amount of CO2 gas mixed in is adjusted according to the H2 / CO ratio in the reducing gas to ensure that the mass of the reducing gas remains unchanged.

[0045] In a gas-based vertical shaft furnace, the oxidation degree of the reducing gas is adjusted to reduce the low-temperature reduction pulverization rate of vanadium-titanium magnetite oxide pellets, ensuring that the vanadium-titanium pellets meet the feed standards for the Hill process (HYL) vertical shaft furnace. The composition of the vanadium-titanium magnetite oxide pellets includes:

[0046] TFe=53.0–58.0 wt%, TiO2=8.0–15.0 wt%, SiO2=2.0–6.0 wt%, MgO=1.0–3.0 wt%, Al2O3=2.0–5.0 wt%.

[0047] Because existing vanadium-titanium magnetite oxide pellets cannot meet the above LTD requirements within the effective reducing gas composition H2 / CO range of 2-10. +6.3 The invention, through a low-temperature reduction process in a reduction furnace, achieves a low-temperature reduction pulverization rate (LTD+6.3>80%) and an unbroken rate (UBI>90%) within the effective component H2 / CO range of 2-10, meeting the international mainstream gas-based vertical shaft furnace technical requirements. This invention effectively reduces the low-temperature reduction pulverization rate of vanadium-titanium magnetite oxide pellets, enabling them to meet the feed standards of the Hill process (HYL) vertical shaft furnace.

[0048] Specifically, based on the stated H2 / CO ratio, the amount of CO2 gas mixed in is as follows:

[0049] When H2 / CO = 2-4 (volume fraction), the amount of CO2 mixed in is 6-8% (volume fraction).

[0050] When H2 / CO = 4-6 (volume fraction), the amount of CO2 mixed in is 4-6% (volume fraction).

[0051] When H2 / CO = 6-8 (volume fraction), the amount of CO2 mixed in is 3-5% (volume fraction).

[0052] When H2 / CO = 8-10 (volume fraction), the amount of CO2 mixed in is 2-4% (volume fraction).

[0053] In an embodiment of the present invention, the method for reducing the pulverization rate of vanadium-titanium magnetite gas-based vertical shaft furnace smelting at low temperatures includes the following steps in the low-temperature reduction pulverization test standard:

[0054] The test temperature was 500℃. After drying the pellets in a drying oven for 4 hours, 500 g ± 1 g of oxidized pellets were weighed and the total number of pellets was counted. Then the pellets were loaded into the reaction tube.

[0055] The reaction tube is placed in the reduction furnace, and the reduction furnace begins to heat up. After the furnace charge temperature rises to 200°C, nitrogen gas is introduced at a rate of 5 L / min, and the temperature continues to rise under nitrogen protection.

[0056] After the furnace charge temperature is raised to 500℃ and stabilized, reducing gas is introduced at 15 L / min for 2 h. After the reduction experiment is completed, the reducing gas is turned off, nitrogen is introduced at 8 L / min, the reaction tube is removed from the furnace and cooled to room temperature.

[0057] After reduction, the furnace charge was removed, weighed, and placed in a rotating drum. It was rotated 300 times at 18 r / min. After removal, it was passed through 6.3 mm and 3.2 mm round-hole sieves. The number of intact pellets was then counted, and the low-temperature pulverization index (LTD) was calculated. +6.3 ) and undamaged rate UBI.

[0058] Among them, the low temperature pulverization index (LTD) +6.3 The breakage rate (UBI) and undamaged rate (UBI) are calculated using the following formulas:

[0059] LTD +6.3 = (m1 / m0) × 100

[0060] UBI = (n2 / n1) × 100

[0061] Where m0 is the original weight of the sample (g); m1 is the mass of the portion remaining on the sieve after sieving with a 6.3 mm sieve (g); n1 is the initial number of pellets; and n2 is the final number of unbroken pellets.

[0062] The present invention discloses a method for reducing the low-temperature reduction pulverization rate of vanadium-titanium magnetite smelting in a gas-based vertical shaft furnace. By adjusting the oxidation degree of the reducing gas in the gas-based vertical shaft furnace smelting process, the low-temperature reduction pulverization rate of vanadium-titanium magnetite oxide pellets is successfully reduced, meeting the requirements of mainstream international gas-based vertical shaft furnace technology. This method is expected to improve the efficiency and yield of the vanadium-titanium magnetite smelting process, thus having broad application prospects in industrial production.

[0063] The specific embodiments of the present invention will be further illustrated below through implementation examples, but the specific embodiments of the present invention are not limited to the following embodiments.

[0064] Example 1

[0065] The embodiments of the present invention provide a method for reducing the pulverization rate of low-temperature reduction in vanadium-titanium magnetite gas-based vertical shaft furnace smelting. In the gas-based vertical shaft furnace, the quality of the reducing gas is maintained, including the total content of H2+CO and the H2 / CO ratio; the oxidation degree of the reducing gas is adjusted by replacing N2 in the reducing gas with 2-8% CO2 gas.

[0066] In this embodiment, the composition of vanadium-titanium magnetite concentrate oxide pellets is shown in Table 1:

[0067] Table 1. Composition of vanadium-titanium magnetite oxide pellets (wt%)

[0068]

[0069] When the reducing gas H2 / CO = 2, the pellet pulverization rate (LTD) +6.3 The pellet pulverization rate (LTD+6.3) and unbroken pellet (UBI) were 63.09% and 53.85%, respectively, significantly lower than the feed standards for the Hill process (HYL) shaft furnace. By mixing 8% (volume fraction) of reducing gas with CO2, the pellet pulverization rate (LTD+6.3) and unbroken pellet (UBI) could reach 85.12% and 92.40%, respectively, meeting the feed standards for the Hill process (HYL) shaft furnace.

[0070] Example 2

[0071] The embodiments of the present invention provide a method for reducing the pulverization rate of low-temperature reduction in vanadium-titanium magnetite gas-based vertical shaft furnace smelting. In the gas-based vertical shaft furnace, the quality of the reducing gas is maintained, including the total content of H2+CO and the H2 / CO ratio; the oxidation degree of the reducing gas is adjusted by replacing N2 in the reducing gas with 2-8% CO2 gas.

[0072] In this embodiment, the composition of vanadium-titanium magnetite concentrate oxide pellets is shown in Table 2:

[0073] Table 2 Composition of vanadium-titanium magnetite oxide pellets (wt%)

[0074]

[0075] When the reducing gas H2 / CO = 5, the pellet pulverization rate (LTD) +6.3 The pellet pulverization rate (LTD+6.3) and unbroken pellet (UBI) were 71.67% and 80.0%, respectively, which are lower than the feed standards for the Hill process (HYL) shaft furnace. By mixing 5% (volume fraction) of reducing gas with CO2 and replacing the original nitrogen content, the pellet pulverization rate (LTD+6.3) and unbroken pellet (UBI) can reach 81.34% and 91.15%, respectively, meeting the feed standards for the Hill process (HYL) shaft furnace.

[0076] Example 3

[0077] The embodiments of the present invention provide a method for reducing the pulverization rate of low-temperature reduction in vanadium-titanium magnetite gas-based vertical shaft furnace smelting. In the gas-based vertical shaft furnace, the quality of the reducing gas is maintained, including the total content of H2+CO and the H2 / CO ratio; the oxidation degree of the reducing gas is adjusted by replacing N2 in the reducing gas with 2-8% CO2 gas.

[0078] In this embodiment, the composition of vanadium-titanium magnetite concentrate oxide pellets is shown in Table 3:

[0079] Table 3. Composition of vanadium-titanium magnetite oxide pellets (wt%)

[0080]

[0081] When the reducing gas H2 / CO ratio is 8, the pellet pulverization rate (LTD) +6.3 The pulverization rate and unbroken ratio (UBI) were 73.85% and 91.25%, respectively. The pulverization rate was lower than the feed standard for the Hill process (HYL) shaft furnace, while the unbroken ratio met the feed standard for the Hill process (HYL) shaft furnace. By mixing 4% (volume fraction) of reducing gas with CO2 to replace the original nitrogen content, the pulverization rate (LTD+6.3) and unbroken ratio (UBI) of the pellets reached 80.86% and 93.90%, respectively, both of which met the feed standard for the Hill process (HYL) shaft furnace.

[0082] In summary, the method of this invention effectively reduces the low-temperature reduction pulverization rate of vanadium-titanium magnetite oxide pellets by adjusting the oxidation degree of the reducing gas, thereby improving the efficiency of the smelting process. A lower pulverization rate means that more oxide pellets can remain intact during the low-temperature reduction process, reducing losses during smelting. This allows vanadium-titanium magnetite smelted in a gas-based shaft furnace to meet the requirements of mainstream international gas-based shaft furnace technologies, particularly regarding the low-temperature reduction pulverization rate and the rate of unbroken pellets. While meeting international requirements, the total mass of the reducing gas and the hydrogen-to-carbon monoxide ratio remain unchanged. This ensures that while reducing the pulverization rate, the quality and properties of the reducing gas required for the smelting process are maintained. By reducing the pulverization rate, this invention helps reduce raw material waste and improve resource utilization efficiency. This is of great significance for sustainable production and environmental protection. By optimizing the oxidation degree of the reducing gas, the low-temperature reduction pulverization rate of vanadium-titanium magnetite smelting in a gas-based shaft furnace is reduced, smelting efficiency is improved, international requirements are met, and there are broad application prospects, potentially bringing multiple economic and environmental benefits.

[0083] The above are exemplary embodiments disclosed in this invention. However, it should be noted that various changes and modifications can be made without departing from the scope of the embodiments of this invention as defined by the claims. The functions, steps, and / or actions of the methods according to the disclosed embodiments described herein do not need to be performed in any particular order. Furthermore, although the elements disclosed in the embodiments of this invention may be described or claimed individually, they may be understood as multiple unless explicitly limited to a singular number.

[0084] It should be understood that, as used herein, the singular form "a" is intended to include the plural form as well, unless the context clearly supports an exception. It should also be understood that, as used herein, "and / or" refers to any and all possible combinations of one or more of the associatedly listed items. The embodiment numbers disclosed above are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0085] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention (including the claims) is limited to these examples. Within the framework of the invention, technical features of the above embodiments or different embodiments can be combined, and many other variations of different aspects of the invention exist, which are not provided in the details for the sake of brevity. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the invention should be included within the protection scope of the invention.

Claims

1. A method for reducing the pulverization rate of low-temperature reduction in vanadium-titanium magnetite gas-based vertical shaft furnace smelting, characterized in that, The method includes the following steps: In a gas-based vertical shaft furnace, maintain the quality of the reducing gas, including the total H2+CO content and the H2 / CO volume ratio; The oxidation degree of the reducing gas is adjusted by replacing N2 in the reducing gas with CO2 gas, which accounts for 2-8% of the total volume. Adjusting the oxidation degree of the reducing gas includes mixing CO2 gas into the reducing gas. The amount of CO2 gas mixed in is adjusted according to the volume ratio of H2 / CO in the reducing gas, where H2 / CO = 2-10.

2. The method for reducing the pulverization rate of low-temperature reduction in vanadium-titanium magnetite gas-based vertical shaft furnace smelting according to claim 1, characterized in that, In a gas-based vertical shaft furnace, the oxidation degree of the reducing gas is adjusted to reduce the low-temperature reduction pulverization rate of vanadium-titanium magnetite oxide pellets, ensuring that the vanadium-titanium pellets meet the feed standards for the Hill process vertical shaft furnace. The composition of the vanadium-titanium magnetite oxide pellets includes: TFe=53.0–58.0 wt%, TiO2=8.0–15.0 wt%, SiO2=2.0–6.0 wt%, MgO=1.0–3.0 wt%, Al2O3=2.0–5.0 wt%.

3. The method for reducing the pulverization rate of low-temperature reduction in vanadium-titanium magnetite gas-based vertical shaft furnace smelting according to claim 2, characterized in that, In a vertical shaft furnace, the low-temperature reduction process of vanadium-titanium magnetite oxide pellets meets the low-temperature reduction pulverization rate (LTD) required by mainstream international gas-based vertical shaft furnace technology. +6.3 >80% and undamaged rate UBI>90%.

4. The method for reducing the pulverization rate of low-temperature reduction in vanadium-titanium magnetite gas-based vertical shaft furnace smelting according to claim 1, characterized in that, According to the H2 / CO volume ratio, when the H2 / CO volume ratio is 2, the volume fraction of CO2 mixed in is 8%.

5. The method for reducing the pulverization rate of low-temperature reduction in vanadium-titanium magnetite gas-based vertical shaft furnace smelting according to claim 1, characterized in that, According to the H2 / CO volume ratio, when the H2 / CO volume ratio is 5, the volume fraction of CO2 mixed in is 5%.

6. The method for reducing the pulverization rate of low-temperature reduction in vanadium-titanium magnetite gas-based vertical shaft furnace smelting according to claim 1, characterized in that, Based on the H2 / CO volume ratio, when the H2 / CO volume ratio is 8, the volume fraction of CO2 mixed in is 4%.

7. The method for reducing the pulverization rate of low-temperature reduction in vanadium-titanium magnetite gas-based vertical shaft furnace smelting according to claim 1, characterized in that, The method for reducing the pulverization rate of vanadium-titanium magnetite gas-based vertical shaft furnace smelting at low temperatures includes the following steps in the low-temperature reduction pulverization test standard: The test temperature was 500℃. After drying the pellets in a drying oven for 4 hours, 500 g ± 1 g of oxidized pellets were weighed and the total number of pellets was counted. Then the pellets were loaded into the reaction tube. The reaction tube is placed in the reduction furnace, and the reduction furnace begins to heat up. After the furnace charge temperature rises to 200°C, nitrogen gas is introduced at a rate of 5 L / min, and the temperature continues to rise under nitrogen protection. After the furnace charge temperature is raised to 500℃ and stabilized, reducing gas is introduced at 15 L / min for 2 h. After the reduction experiment is completed, the reducing gas is turned off, nitrogen is introduced at 8 L / min, the reaction tube is removed from the furnace and cooled to room temperature. After reduction, the furnace charge was weighed and placed in a rotating drum. It was rotated 300 times at a speed of 18 r / min. After being removed, it was passed through 6.3 mm and 3.2 mm round hole sieves in sequence. Then, the number of intact pellets was counted, and the low-temperature pulverization index and the unbroken rate were calculated.

8. The method for reducing the pulverization rate of low-temperature reduction in vanadium-titanium magnetite gas-based vertical shaft furnace smelting according to claim 7, characterized in that, Low Temperature Powdering Index (LTD) +6.3 The undamaged product index (UBI) is calculated using the following formula: LTD +6.3 =(m1 / m0)×100 UBI = (n2 / n1) × 100 Where m0 is the original weight of the sample (g); m1 is the mass of the portion remaining on the sieve after sieving with a 6.3 mm sieve (g); n1 is the initial number of pellets; and n2 is the final number of unbroken pellets.

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