Vanadium-titanium magnetite deep reduction carbonaceous reducing agent dosage regulation method

Abstract

The application discloses a kind of carbonaceous reducing agent dosage regulation and control methods for vanadium-titanium magnetite deep reduction, by analyzing the composition characteristics of vanadium-titanium magnetite and flux to be reduced, and based on the selection of slag type system coupled with the change of vanadium-titanium magnetite metallization rate, on the basis of considering the oxide and residual carbon residue in product, focus on the correction coefficient of theoretical carbon content required by electric furnace smelting of multi-factor influence is defined, and then a more accurate electric furnace smelting reducing agent dosage composite prediction model is constructed, which can more accurately match the process requirements on site through the prediction model, and then ensure the efficient use of carbon resources in the smelting stage and protect product quality, reduce energy consumption and carbon emission per ton of iron, help to achieve the double carbon goal. The method of the application is simple to operate, easy to flexibly regulate and control, can cover and be suitable for most vanadium-titanium magnetite electric furnace deep reduction smelting conditions, has strong adaptability, and is easy to large-scale practice, popularization and application.

Description

Technical Field

[0001] This invention relates to metallurgical reduction technology, specifically to a method for controlling the dosage of carbonaceous reducing agent in the deep reduction of vanadium-titanium magnetite, belonging to the field of deep reduction technology of vanadium-titanium magnetite. Background Technology

[0002] As an important strategic resource both domestically and internationally, vanadium-titanium magnetite is the primary raw material for vanadium production and a key mineral for refining titanium and iron. Domestically, vanadium-titanium magnetite deposits are mainly distributed in the Panzhihua-Xichang region of Sichuan and the Chengde region of Hebei. A large vanadium-titanium magnetite deposit was discovered in Xinjiang in 2024. Internationally, vanadium-titanium magnetite deposits are mainly distributed in countries such as South Africa, Russia, and Canada. With the comprehensive advancement of high-quality economic and social development in my country and the rapid advancement of key sectors, the resource risks of maintaining a sustained increase in vanadium and titanium supply in the future critical mineral supply chain will become increasingly apparent. Therefore, focusing on vanadium and titanium and deepening the research and application of key technologies for the comprehensive utilization of vanadium-titanium magnetite resources both domestically and internationally is of great significance.

[0003] In China, the blast furnace-converter process is mainly used to process vanadium-titanium magnetite concentrate produced through beneficiation. While this process offers advantages such as high production efficiency and large scale, it suffers from the drawback of sacrificing titanium for iron and vanadium, resulting in significant titanium resource loss and environmental pollution. Domestic basic research and international production practices have shown that non-blast furnace smelting of vanadium-titanium magnetite concentrate or lump ore is a process that can achieve comprehensive utilization of iron, vanadium, and titanium resources. Among these methods, the pre-reduction-electric furnace smelting / deep reduction method is highly recommended. Its advantages include the ability to achieve full vanadium-titanium ore smelting, high titanium content in the slag, and mature vanadium extraction technology from vanadium-containing molten iron.

[0004] The pre-reduction-electric furnace smelting / deep reduction method typically involves first pre-reducing vanadium-titanium magnetite in a rotary hearth furnace, rotary kiln, or hydrogen-based vertical shaft furnace using a carbonaceous or hydrogen-rich gas reducing agent. The pre-reduced vanadium-titanium magnetite is then subjected to high-temperature metallurgical separation of the metal and slag in an electric furnace. Regarding this technology, in the "Experimental Study on Optimization of Direct Reduction-Electrothermal Smelting Process of Vanadium-Titanium Ore Lumps in Rotary Kiln," small-scale electric furnace smelting tests were conducted using the reduction products of South African vanadium-titanium ore lumps as raw materials and a medium-frequency induction furnace. To improve the recovery rate of valuable components in the smelted iron, a suitable carbon ratio of 1.6 was determined. Patent document CN202211147454.2 provides a slag-forming method for electric furnace smelting of vanadium-titanium magnetite, where the amount of reducing agent added is calculated based on the carbon content as 5-15 wt% of the oxide pellets. Patent document 202111477248.3 describes a method for smelting vanadium-containing pig iron by-product vanadium slag and acid-soluble titanium slag from vanadium-titanium magnetite without adding desulfurization slag-forming lime. It mentions that when smelting the reducing raw materials, the method further includes mixing the reducing raw materials with a carbonaceous reducing agent accounting for 3-5% of the total mass of the pre-reduced raw materials. While these technical solutions all involve the amount of fuel added in the deep reduction process, they are all based on simple and crude empirical values, making it difficult to adapt to the actual working conditions of fluctuating composition and state of the pre-reduced raw materials. In particular, they cannot provide accurate reducing agent dosages in a timely manner for changes in the pre-reduction degree of the raw materials, easily leading to insufficient or excessive reducing agent addition, thus affecting the reduction effect and increasing carbon emissions. Summary of the Invention

[0005] To address the issue that existing methods for calculating carbon content in electric arc furnace (EAF) smelting are numerous but lack precision, this invention discloses a method for controlling the dosage of carbonaceous reducing agent in the deep reduction of vanadium-titanium magnetite. Based on the fluctuations in the core components of the vanadium-titanium magnetite to be reduced and the flux within the EAF, this method focuses on defining correction coefficients for the theoretical carbon content required for EAF reduction smelting, which are influenced by multiple factors. This constructs a more accurate composite model for reducing agent dosage in EAF smelting, more precisely matching on-site process requirements and ensuring efficient utilization of carbon resources during the smelting stage. Furthermore, this patent comprehensively considers carbon consumption during the smelting process and residual carbon in the product, achieving precise control of the reducing agent addition at the source. This ensures smelting efficiency while reducing energy consumption and carbon emissions per ton of iron, contributing to the achievement of dual carbon goals.

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

[0007] A method for controlling the dosage of carbonaceous reducing agent in the deep reduction of vanadium-titanium magnetite, the method comprising the following steps:

[0008] S1. Based on the changes in the compositional characteristics of the vanadium-titanium magnetite to be reduced and the flux, a preliminary prediction model for the amount of carbonaceous reducing agent based on the changes in the metallization rate of vanadium-titanium magnetite is established.

[0009] S2. Based on the changes in flux type coupled with the preliminary prediction model, an optimized prediction model for the amount of carbonaceous reducing agent based on the changes in the metallization rate and slag type of vanadium-titanium magnetite is established.

[0010] S3. The actual amount of carbonaceous reducing agent used in the deep reduction of vanadium-titanium magnetite in an electric furnace is calculated using the obtained optimized prediction model.

[0011] Preferably, step S1 includes:

[0012] S101. The vanadium-titanium magnetite to be reduced is mixed with flux to obtain a mixture. The composition of the mixture is analyzed to obtain the content data of each oxide in the mixture.

[0013] S102. Calculate the theoretical carbon consumption required for the reduction of the current mixture based on the content data of each oxide in the mixture.

[0014] S103. Based on the theoretical carbon consumption and the residual amount of each oxide and carbon under the working conditions, the required actual carbon consumption and the corresponding actual amount of carbonaceous reducing agent are calculated.

[0015] S104. Mix the vanadium-titanium magnetite with different metallization rates to be reduced with flux to obtain a mixture. Repeat steps S101 to S103 to obtain the actual amount of carbonaceous reducing agent required for the mixture with different metallization rates, and then establish a preliminary prediction model for the amount of carbonaceous reducing agent based on the change in the metallization rate of vanadium-titanium magnetite.

[0016] Preferably, in step S101, the oxide is including, but is not limited to, at least one of FeO, Fe2O3, V2O5, SiO2, TiO2, CaO, MgO, and Al2O3, preferably FeO, Fe2O3, V2O5, and SiO2. (Quantitative analysis of the components is recommended using chemical titration, AAS, or ICP-OES / MS, etc.).

[0017] Preferably, in step S103, the residual conditions of each oxide and carbon specifically include:

[0018] When the designed reduction temperature of the electric furnace is 1450~1700℃ and the smelting time is 3~6h: the residual TFe in the slag is less than 2.5% (preferably 0.4~2.2%), the residual V2O5 in the slag is less than 20% (preferably 3~15%), and the residual SiO2 in the slag is greater than 95% (preferably greater than 97%); the residual carbon content in the molten iron does not exceed 4% of the total mass of the molten iron (preferably 1~3%); and the residual carbon content in the slag does not exceed 0.5% of the total mass of the slag (preferably 0.1~0.3%).

[0019] It should be noted that the values ​​of each residual rate can be determined by taking the average value of multiple (e.g., 3) parallel industrial tests (furnace capacity ≥ 500 kg) and then verifying them by chemical titration and ICP-OES / MS dual methods.

[0020] As a preferred option, the preliminary prediction model is as follows:

[0021] y0=a(-kx+c) / r (1).

[0022] In equation (1), y0 is the preliminary predicted value of the amount of carbonaceous reducing agent, kg / 100kg-vanadium-titanium ore. x is the metallization rate of the vanadium-titanium magnetite to be reduced, %. a is the first-order correction coefficient, with a value of 1~1.3. k is the operating condition coefficient, with a value of 0.15~0.19. c is the operating condition constant, with a value of 10~20. r is the fixed carbon content of the carbonaceous reducing agent, %.

[0023] As a preferred embodiment, the optimized prediction model is as follows:

[0024] y0=b[a(-kx+c)] / r (2).

[0025] In equation (2), y0 is the preliminary predicted value of the amount of carbonaceous reducing agent, kg / 100kg-vanadium-titanium ore. x is the metallization rate of the vanadium-titanium magnetite to be reduced, %. a is the first-order correction coefficient, with a value of 1~1.3. b is the second-order correction coefficient, with a value of 1~1.15. k is the operating condition coefficient, with a value of 0.15~0.19. c is the operating condition constant, with a value of 10~20. r is the fixed carbon content of the carbonaceous reducing agent, %. (Preferably, the fixed carbon content is not less than 80%).

[0026] As a preferred method, based on the change in the ratio of metallic iron content to total iron content in the vanadium-titanium magnetite to be reduced, the actual metallization rate x of different vanadium-titanium magnetites to be reduced is obtained, and then:

[0027] When x < 30%, a in equations (1)-(2) ∈ (1.15, 1.30).

[0028] When 30%≤x≤60%, a∈[1.07,1.15] in equations (1)-(2).

[0029] When 60% < x, a ∈ [1.0, 1.07] in equations (1)-(2).

[0030] Preferably, in step S1, the flux is a conventional flux (any one of calcium-containing flux, silicon-containing flux, or magnesium-containing flux), such as limestone, dolomite, or silica. The amount of flux added is generally 2-10% of the mass of the vanadium-titanium magnetite to be reduced (this can be adjusted according to the actual alkalinity requirements of the working conditions).

[0031] Preferably, in step S2, the flux is a mixed flux composed of calcium-containing flux and silicon-containing flux, or a mixed flux composed of magnesium-containing flux and silicon-containing flux. It should be noted that the terms calcium-containing flux, silicon-containing flux, magnesium-containing flux, etc., refer to the flux containing calcium, silicon, or magnesium as the main elements, not just calcium, silicon, and magnesium. For example, a calcium-containing flux can be limestone or a mixed flux primarily composed of limestone; a silicon-containing flux can be silica or a mixed flux primarily composed of silica; and a magnesium-containing flux can be dolomite or a mixed flux primarily composed of dolomite.

[0032] Preferably, the silicon-containing flux is silicon oxide and / or silicon oxide-containing minerals. The calcium-containing flux is calcium oxide and / or calcium-containing minerals. The magnesium-containing flux is magnesium oxide and / or magnesium-containing minerals.

[0033] Preferably, when the flux is a mixture of calcium-containing flux and silicon-containing flux, the amount of flux added is such that the basicity of the mixture is 0.8 to 1.4. In equation (2), b ∈ [1.0, 1.1].

[0034] Preferably, when the flux is a mixture of magnesium-containing flux and silicon-containing flux, the amount of flux added is such that the basicity of the mixture is 0.4~1.0. In formula (2), b∈[1.05, 1.15].

[0035] Preferably, the vanadium-titanium magnetite to be reduced is pre-reduced vanadium-titanium magnetite from a rotary kiln and / or a gas-based vertical shaft furnace. Preferably, the particle size of the vanadium-titanium magnetite to be reduced is 5-25 mm.

[0036] Preferably, the carbonaceous reducing agent includes at least one of pulverized coal, charcoal powder, and coke powder. Preferably, the particle size of the carbonaceous reducing agent is 5-15 mm.

[0037] In this invention, the vanadium-titanium magnetite to be reduced refers to a pre-reduced raw material with a certain metallization rate (MFe / TFe) after pre-reduction by a front-end rotary kiln, rotary hearth furnace, or vertical shaft furnace. This pre-reduced raw material needs to be deeply reduced in an electric furnace together with a flux containing calcium, magnesium, and silicon, as well as a carbonaceous reducing agent, to obtain molten iron and slag. The main function of the flux is to promote the melting of the pre-reduced raw material, lower the melting temperature, increase the melting rate, and slag formation and batching during the metallurgical process, helping to separate impurities from metals. The main function of the carbonaceous reducing agent is to reduce the iron, vanadium, and other metal oxides in the pre-reduced raw material to their elemental form. In the actual deep reduction smelting process of vanadium-titanium magnetite, the addition of a sufficient amount of carbonaceous reducing agent is the basic requirement to meet the deep reduction of pre-reduced vanadium-titanium magnetite. However, the addition of too much carbonaceous reducing agent will cause unnecessary waste and additional carbon emissions. In addition, too much reducing agent may also lead to over-reduction, resulting in a decrease in the quality of molten iron. This invention, through research, has discovered that the composition of pre-reduced raw materials fluctuates relatively greatly due to differences in their original sources and pre-reduction processes. In particular, changes in the metallization rate significantly affect the amount of reducing agent used in subsequent deep reduction in electric furnaces. Therefore, this invention, based on the fluctuations in the core components of the vanadium-titanium magnetite to be reduced and the flux in the electric furnace, focuses on defining the correction coefficient for the theoretical carbon content required for electric furnace reduction smelting under the influence of multiple factors. Ultimately, a more accurate composite model for the amount of reducing agent used in electric furnace smelting is constructed. This model can more accurately match the on-site process requirements, thereby ensuring the efficient utilization of carbon resources during the smelting stage while ensuring the quality of molten iron.

[0038] In this invention, a preliminary prediction model for the amount of carbonaceous reducing agent based on the change in the metallization rate of vanadium-titanium magnetite and flux is first established based on the changes in the compositional characteristics of the vanadium-titanium magnetite to be reduced and the flux. The compositional characteristics of the vanadium-titanium magnetite to be reduced and the flux refer to the mass content of core elements such as TFe, MFe, FeO, Fe2O3, V2O5, and SiO2 (and may also include TiO2, CaO, MgO, and Al2O3) in the mixture (vanadium-titanium magnetite to be reduced and flux). The total mass of each oxide entering the electric furnace can be obtained by using the mass of the vanadium-titanium magnetite to be reduced and the content of each oxide. For example, under the condition that oxides such as FeO, Fe2O3, V2O5, and SiO2 are the core components, let the mass of vanadium-titanium magnetite in the electric furnace feed be m. k The total iron content is C TFe The iron content is C MFe The FeO content is C FeO-1 The Fe2O3 content is C Fe2O3-1 The V2O5 content is C V2O5-1 The SiO2 content is C SiO2-1 The flux containing calcium, magnesium, and silicon has a mass of m. r The FeO content is C FeO-2The Fe2O3 content is C Fe2O3-2 The V2O5 content is C V2O5-2 The SiO2 content is C SiO2-2 Therefore, the metallization rate x of the pre-reduced vanadium-titanium magnetite, the main material, can be derived as: MFe / C TFe Furthermore, the total masses of FeO, Fe2O3, V2O5, and SiO2 entering the electric furnace are respectively: m FeO =m k ×C FeO-1 +m r ×C FeO-2 m Fe2O3 =m k ×C Fe2O3-1 +m r ×C Fe2O3-2 m V2O5 =m k ×C V2O5-1 +m r ×C V2O5-2 m SiO2 =m k ×C SiO2-1 +m r ×C SiO2-2 To achieve precise quality control of carbonaceous reducing agents during deep reduction in electric furnaces, the reaction processes and reducibility of each substance in the smelting process must be fully considered. Based on the premise of deep reduction of iron and vanadium and minimal reduction of silicon, the oxygen atom mass m of the oxides of iron, vanadium, and titanium in the mixture of pre-vanadium-titanium magnetite and flux to be reduced is... O for:

[0039] m O =m FeO ×16 / 72+m Fe2O3 ×48 / 160+m V2O5 ×80 / 181.88×(1-r V2O5 )+m SiO2 ×32 / 60×(1-r SiO2 ).

[0040] Where, r V2O5 The percentage of V2O5 remaining in the slag after deep reduction in the raw material to be reduced, which is 0%~20%, preferably 3%~15%, and more preferably 5%~10%; SiO2 The percentage of SiO2 remaining in the slag after deep reduction of the raw material to be reduced is 95% to 100%.

[0041] Furthermore, considering that a small amount of FeO may remain unreduced in the slag, the mass m of the oxygen atoms remaining in the slag from FeO is... O-rz for:

[0042] m O-rz =(m k +m r )×C TFe-p ×r FeO ×16 / 56.

[0043] Among them, C TFe-p The weighted average of the TFe content of all raw materials (pre-reduced vanadium-titanium magnetite, calcium-, magnesium-, and silicon-containing flux), r FeO The percentage of TFe remaining in the slag after deep reduction of the raw material to be reduced is 0% to 2.5%, preferably 0.4% to 2.2%. Finally, the actual mass m of the oxygen atoms to be reduced is determined. O-sj For: m O-sj =m O -m O-rz The actual amount of oxygen atoms to be reduced, n, is... O-sj For: n O-sj =m O-sj / 16. The carbonaceous reducing agent added during the deep reduction process in the electric furnace will be converted into (C) in the slag and [C] in the molten iron. Oxygen atoms in the iron / vanadium oxides are removed through reactions with [C] and (C): [C] + O = CO(g), (C) + O = CO(g). Therefore, theoretically, the fixed carbon molar mass n required to completely remove O from the core oxides in the mixture is... c With mass m c They are respectively: m c =Mc×n c =Mc×n O-sj =12×n O-sj It should be noted that the residual proportions of each component refer to percentages relative to the original mass of each component. For example, in pre-reduced vanadium-titanium magnetite, if the initial total mass of V₂O₅ is 1000g, when r V2O5 When the percentage is 1%, it means that the mass of V2O5 remaining in the slag is approximately 10g.

[0044] In this invention, after the deep reduction in the electric furnace, both the carburization of the vanadium-containing molten iron and the residual carbon in the titanium slag must be taken into account. Let the carbon content of the vanadium-containing molten iron be denoted as C. ts Its value range is generally 2.5% to 4%, preferably 3% to 3.5%, and the total mass of molten iron is denoted as m. ts The carbon content of titanium slag is denoted as C. tz Its value ranges from 0% to 0.5%, and the total mass of titanium slag is denoted as m. tz Therefore, the total mass m of residual carbon in the electric furnace smelting product can be obtained. ct For: m ct =m ts ×C ts +m tz×C tz Simultaneously, the elemental carbon content (C) of the pre-reduced vanadium-titanium magnetite itself is considered. zdc The amount of carbon it brings in, m zdc For: m zdc =m k ×C zdc Taking into account the carbon content of vanadium-titanium magnetite, the carbon consumption of the reduction reaction, and the residual carbon in the product, the theoretical total carbon required in the electric furnace, m, is calculated. dlpc For: m dlpc =m c +m ct -m zdc Thus, a more precise theoretical carbon content y0=m can be obtained for a pre-reduced feedstock with a specific metallization rate x. c Furthermore, if the fixed carbon content of the externally prepared solid carbonaceous reducing agent is C0, then the corresponding actual amount of carbonaceous reducing agent used is m. csj For: m csj =m dlpc / C0=(m c +m ct -m zdc ) / C0. At the same time, a relatively simple concept is derived: relative to all materials in the electric furnace, the proportion P of the externally supplied solid carbonaceous reducing agent. c For: P c =m csj / (m k +m r +m csj Among them, the solid carbonaceous reducing agent includes one or more of semi-coke, coke, coke fines or anthracite, with a particle size between 5 and 15 mm.

[0045] In this invention, practical research revealed that in actual electric furnace smelting, the influence of multiple factors on the consumption of carbonaceous reducing agents (such as metallization rate and slag type) must be considered. Therefore, a precise definition of the carbon addition correction coefficient is necessary, and a corresponding correction model must be constructed. The reduction processes that vanadium-titanium magnetite with different metallization rates require in the electric furnace with flux and reducing agents vary, resulting in different smelting times. Simultaneously, carbon undergoes reduction, Bourdon reaction, and combustion reactions, leading to different consumption amounts. Therefore, by fully considering the non-target reduction time of carbonaceous reducing agents under actual operating conditions and based on the theoretical carbon addition amounts corresponding to multiple metallization rates, a simple derivation formula for the theoretical dosage of carbonaceous reducing agents is constructed:

[0046] y0=(-kx+c) / r (1-1).

[0047] In equation (1-1), y0 is the preliminary predicted value of the amount of carbonaceous reducing agent, kg / 100kg-vanadium-titanium ore. x is the metallization rate of the vanadium-titanium magnetite to be reduced, %. k is the operating condition coefficient, ranging from 0.15 to 0.19. c is the operating condition constant, ranging from 10 to 20. r is the fixed carbon content of the carbonaceous reducing agent, %. Equation (1-1) allows for a relatively simple derivation of the appropriate amount of carbonaceous reducing agent to be added under conventional smelting conditions for different metallization rates.

[0048] In this invention, the actual metallization rate of the vanadium-titanium magnetite to be reduced fluctuates significantly due to differences in its initial raw material source, pre-reduction equipment, and process. To more accurately correct the relationship between the metallization rate variation and the amount of carbonaceous reducing agent, further research was conducted based on the above-described derivation (1-1), and a first-order correction coefficient 'a' based on the metallization rate variation was introduced. This resulted in a more accurate preliminary prediction model for the amount of carbonaceous reducing agent primarily based on the metallization rate variation of vanadium-titanium magnetite.

[0049] y0=a(-kx+c) / r (1).

[0050] In equation (1), y0 is the preliminary predicted value of the amount of carbonaceous reducing agent, kg / 100kg-vanadium-titanium ore. x is the metallization rate of the vanadium-titanium magnetite to be reduced, %. a is the first-order correction coefficient, with a value of 1~1.3. k is the operating condition coefficient, with a value of 0.15~0.19. c is the operating condition constant, with a value of 10~20. r is the fixed carbon content of the carbonaceous reducing agent, %. Equation (1) can be used to derive the appropriate amount of carbonaceous reducing agent to be added under conventional smelting conditions for different metallization rates with relatively accurate results.

[0051] Furthermore, through in-depth research, the first-order correction coefficient 'a' was further defined, thereby further improving the accurate prediction of the theoretical dosage of carbonaceous reducing agent: when the metallization rate is <30%, the first-order correction coefficient of the theoretical dosage of carbonaceous reducing agent is taken as a1, and the preliminary prediction model of the dosage of carbonaceous reducing agent in the first stage is: y1=a1(-kx+c) / r, where a1∈(1.15, 1.30).

[0052] When the metallization rate is 30~60%, the first-order correction coefficient for the theoretical addition amount of carbonaceous reducing agent is taken as a2. Then the preliminary prediction model for the amount of carbonaceous reducing agent in the first stage is: y1=a2(-kx+c) / r, where a2∈[1.07, 1.15].

[0053] When the metallization rate is >60%, the first-order correction coefficient for the theoretical addition amount of carbonaceous reducing agent is taken as a3. Then the preliminary prediction model for the amount of carbonaceous reducing agent used in the first stage is: y1=a3(-kx+c) / r, where a3∈[1.0, 1.07).

[0054] In this invention, the choice of flux type and control of basicity range, relative to vanadium-titanium magnetite, result in different slag types after smelting: 1) If titanium is not desired for recovery, and only iron and vanadium are needed, a calcium-containing flux can be used, resulting in the formation of perovskite, after which titanium cannot be recovered (vanadium-titanium magnetite blast furnace ironmaking primarily uses perovskite). 2) If iron, vanadium, and titanium are all desired, a magnesium-containing flux is added, resulting in a product with black titanium as the main phase. Research has shown that, within a suitable binary basicity range, considering the influence of the slag type regime, a second-order correction coefficient b is introduced based on the theoretical addition amount of carbonaceous reducing agent according to different titanium slag phase compositions, based on the first-stage model. This leads to a more accurate optimization prediction model for the amount of carbonaceous reducing agent, primarily based on changes in the metallization rate of vanadium-titanium magnetite and changes in the slag type regime.

[0055] y0=b[a(-kx+c)] / r (2).

[0056] In equation (2), y0 is the preliminary predicted value of the amount of carbonaceous reducing agent, kg / 100kg-vanadium-titanium ore. x is the metallization rate of the vanadium-titanium magnetite to be reduced, %. a is the first-order correction coefficient, with a value of 1~1.3. b is the second-order correction coefficient, with a value of 1~1.15. k is the operating condition coefficient, with a value of 0.15~0.19. c is the operating condition constant, with a value of 10~20. r is the fixed carbon content of the carbonaceous reducing agent, %. Equation (2) can more accurately derive the appropriate amount of carbonaceous reducing agent to be added under conventional smelting regime when different metallization rates are coupled with different slag types.

[0057] Furthermore, through in-depth research, the second-order correction coefficient b was further defined, thereby further improving the accurate prediction of the theoretical addition amount of carbonaceous reducing agent: when the main addition of calcium-containing flux / silicon-containing flux is used to adjust the binary basicity between 0.8 and 1.4, and the generated titanium slag is mainly composed of perovskite and rutile (CaO content is between 6% and 12%), the second-order correction coefficient of the theoretical addition amount of carbonaceous reducing agent is taken as b1, and a two-stage composite correction model can be constructed: y2=b1[a(-kx+c)] / r, where b1∈[1.0, 1.1].

[0058] When the main addition of magnesium-containing flux / silicon-containing flux is used to adjust the binary basicity between 0.4 and 1.0, and the titanium slag is mainly composed of black titanium stone and spinel (the MgO content in the titanium slag is about 6% to 12%), the second-order correction coefficient of the theoretical addition amount of carbonaceous reducing agent is taken as b2, and a two-stage composite correction model can be constructed: y2=b2[a(-kx+c)] / r, where b2∈[1.05, 1.15].

[0059] It should be noted that all formulas in this invention were obtained by the inventors based on experimental and engineering applications, and all calculations were obtained by substituting the converted values ​​into the formulas according to the prescribed units (after converting the units, only the values ​​are substituted into the formulas for calculation, not the units; the units are only used to adjust the size of the values).

[0060] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0061] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0062] 1. This invention analyzes the compositional characteristics of reduced vanadium-titanium magnetite and flux, and selects the slag type based on the metallization rate variation of vanadium-titanium magnetite coupled with the selection of the slag type system. Considering the oxides and residual carbon in the product, it focuses on defining the correction coefficient of the theoretical carbon content required for electric furnace smelting under the influence of multiple factors. Thus, a more accurate composite prediction model for the amount of reducing agent used in electric furnace smelting is constructed. This prediction model can more accurately match the on-site process requirements, thereby ensuring the efficient utilization of carbon resources in the smelting stage and guaranteeing product quality.

[0063] 2. The method of the present invention is simple to operate, easy to adjust flexibly, can cover and is suitable for most deep reduction smelting conditions of vanadium-titanium magnetite electric furnace, has strong adaptability, and is easy to promote and apply on a large scale. Attached Figure Description

[0064] Figure 1 This is a flowchart illustrating the method described in this invention. Detailed Implementation

[0065] The technical solution of the present invention will be illustrated below with examples. The scope of protection sought by the present invention includes, but is not limited to, the following embodiments.

[0066] Example 1

[0067] like Figure 1 As shown, a method for controlling the dosage of carbonaceous reducing agent in the deep reduction of vanadium-titanium magnetite includes the following steps:

[0068] S1. Based on the changes in the compositional characteristics of the vanadium-titanium magnetite to be reduced and the flux, a preliminary prediction model for the amount of carbonaceous reducing agent based on the changes in the metallization rate of vanadium-titanium magnetite is established.

[0069] S2. Based on the changes in flux type coupled with the preliminary prediction model, an optimized prediction model for the amount of carbonaceous reducing agent based on the changes in the metallization rate and slag type of vanadium-titanium magnetite is established.

[0070] S3. The actual amount of carbonaceous reducing agent used in the deep reduction of vanadium-titanium magnetite in an electric furnace is calculated using the obtained optimized prediction model.

[0071] Step S1 includes:

[0072] S101. The vanadium-titanium magnetite to be reduced is mixed with flux to obtain a mixture. The composition of the mixture is analyzed to obtain the content data of each oxide in the mixture.

[0073] S102. Calculate the theoretical carbon consumption required for the reduction of the current mixture based on the content data of each oxide in the mixture.

[0074] S103. Based on the theoretical carbon consumption and the residual amount of each oxide and carbon under the working conditions, the required actual carbon consumption and the corresponding actual amount of carbonaceous reducing agent are calculated.

[0075] S104. Mix the vanadium-titanium magnetite with different metallization rates to be reduced with flux to obtain a mixture. Repeat steps S101 to S103 to obtain the actual amount of carbonaceous reducing agent required for the mixture with different metallization rates, and then establish a preliminary prediction model for the amount of carbonaceous reducing agent based on the change in the metallization rate of vanadium-titanium magnetite.

[0076] In step S101, the oxide is FeO, Fe2O3, V2O5, and SiO2.

[0077] In step S103, the residual conditions of each oxide and carbon specifically include:

[0078] When the designed reduction temperature of the electric furnace is 1450~1700℃ and the smelting time is 3~6h: the residual TFe in the slag is less than 2.5%, the residual V2O5 in the slag is less than 20%, and the residual SiO2 in the slag is greater than 90%. The residual carbon content in the molten iron does not exceed 4% of the total mass of the molten iron. The residual carbon content in the slag does not exceed 0.5% of the total mass of the slag.

[0079] In step S1, the preliminary prediction model is as follows:

[0080] y0=a(-kx+c) / r (1).

[0081] In equation (1), y0 is the preliminary predicted value of the amount of carbonaceous reducing agent, kg / 100kg-vanadium-titanium ore. x is the metallization rate of the vanadium-titanium magnetite to be reduced, %. a is the first-order correction coefficient, with a value of 1~1.3. k is the operating condition coefficient, with a value of 0.15~0.19. c is the operating condition constant, with a value of 10~20. r is the fixed carbon content of the carbonaceous reducing agent, %.

[0082] In step S2, the optimized prediction model is as follows:

[0083] y0=b[a(-kx+c)] / r (2).

[0084] In equation (2), y0 is the preliminary predicted value of the amount of carbonaceous reducing agent, kg / 100kg-vanadium-titanium ore. x is the metallization rate of the vanadium-titanium magnetite to be reduced, %. a is the first-order correction coefficient, with a value of 1~1.3. b is the second-order correction coefficient, with a value of 1~1.15. k is the operating condition coefficient, with a value of 0.15~0.19. c is the operating condition constant, with a value of 10~20. r is the fixed carbon content of the carbonaceous reducing agent, %.

[0085] Based on the change in the ratio of metallic iron content to total iron content in the vanadium-titanium magnetite to be reduced, the actual metallization rate x of different vanadium-titanium magnetites to be reduced is obtained, and then:

[0086] When x < 30%, a in equations (1)-(2) ∈ (1.15, 1.30).

[0087] When 30%≤x≤60%, a∈[1.07,1.15] in equations (1)-(2).

[0088] When 60% < x, a ∈ [1.0, 1.07] in equations (1)-(2).

[0089] In step S2, the flux is a mixed flux consisting of a calcium-containing flux and a silicon-containing flux. The silicon-containing flux is silicon oxide and / or a silicon oxide-containing mineral. The calcium-containing flux is calcium oxide and / or a calcium-containing mineral. The amount of flux added is such that the basicity of the mixture is 0.8 to 1.4. In formula (2), b ∈ [1.0, 1.1].

[0090] In step S2, the flux is a mixed flux consisting of a magnesium-containing flux and a silicon-containing flux. The silicon-containing flux is silicon oxide and / or a silicon oxide-containing mineral. The magnesium-containing flux is magnesium oxide and / or a magnesium-containing mineral. The amount of flux added is such that the basicity of the mixture is 0.4~1.0. In formula (2), b∈[1.05, 1.15].

[0091] The vanadium-titanium magnetite to be reduced is derived from pre-reduced vanadium-titanium magnetite produced in a rotary kiln and / or a gas-based vertical shaft furnace. The particle size of the vanadium-titanium magnetite to be reduced is 5-25 mm. The carbonaceous reducing agent includes at least one of pulverized coal, charcoal powder, and coke powder. The particle size of the carbonaceous reducing agent is 5-15 mm.

[0092] Application Example 1

[0093] Proposed operating conditions for deep reduction in electric furnace: proposed melting temperature is approximately 1600℃, and proposed melting time is approximately 3 hours.

[0094] Vanadium-titanium magnetite to be reduced: Various vanadium-titanium magnetite samples from rotary kilns were analyzed. The core component analysis results of each sample are shown in Table 1 below (the component analysis was performed using chemical titration).

[0095]

[0096] The target requirements for smelting conditions are as follows: at least 98% silicon enters the slag, and approximately 2% silicon enters the molten iron. Approximately 10% vanadium enters the slag, and at least 90% vanadium enters the molten iron. Approximately 0.5% iron enters the slag, and at least 99.5% iron enters the molten iron. The residual carbon content in the molten iron shall not exceed 3% of the total mass of the molten iron, and the residual carbon content in the slag shall not exceed 0.1% of the total mass of the slag.

[0097] Samples I through IV were taken separately and mixed with flux (2.5 kg limestone, 2 kg dolomite, and 1 kg silica) for analysis. The theoretical carbon requirement per unit of pre-reduced vanadium-titanium magnetite with different metallization rates was calculated, and the results are shown in Table 2 below.

[0098]

[0099] Based on the results in Table 2, a simple prediction model for the amount of carbonaceous reducing agent based on the change in the metallization rate of vanadium-titanium magnetite was derived:

[0100] y0 = -0.1591x + 16.488. That is, the value of the condition coefficient k under the current working condition is approximately 0.1591, and the value of the condition constant c is approximately 16.488.

[0101] Under the current operating conditions, the first-order correction coefficient 'a' for ore samples I to IV with different metallization rates is set to 1.25, 1.13, 1.10, and 1.04, respectively. Assuming the carbonaceous reducing agent used is semi-coke with a fixed carbon content of approximately 88.5 wt%, the preliminary prediction models for the amount of carbonaceous reducing agent required for each ore sample can be obtained as follows:

[0102] y I =1.25(-0.1591x+16.488) / 0.885.

[0103] y II =1.13(-0.1591x+16.488) / 0.885.

[0104] y III =1.10(-0.1591x+16.488) / 0.885.

[0105] y IV =1.04(-0.1591x+16.488) / 0.885.

[0106] Under the current operating conditions, if a magnesium-containing flux is to be added to every 100 kg of ore sample, with a flux composition of 3.5 kg dolomite, 1 kg limestone, and 1 kg silica, and an alkalinity of approximately 0.7, then the slag will primarily consist of black titanium and forsterite. Therefore, the second-order correction coefficient b is taken as 1.09. Furthermore, the optimized prediction models for the carbonaceous reducing agent dosage corresponding to each ore sample can be obtained as follows:

[0107] y I =1.09×1.25(-0.1591x+16.488) / 0.885≈21.59kg.

[0108] y II =1.09×1.13(-0.1591x+16.488) / 0.885≈14.62kg.

[0109] y III =1.09×1.10(-0.1591x+16.488) / 0.885≈13.25kg.

[0110] y IV =1.09×1.04(-0.1591x+16.488) / 0.885≈7.22kg.

[0111] Based on the above calculation results, different furnace charges were prepared according to Table 3 below. Each furnace charge was then fed into the electric furnace for deep smelting and reduction according to the proposed deep reduction conditions described above, and the product quality and residual carbon content were tested.

[0112]

[0113] Under the current operating conditions, if a calcium-containing flux is to be added to every 100 kg of ore sample, with a flux composition of 3.5 kg limestone, 1 kg dolomite, and 1 kg silica, and an alkalinity of approximately 0.9, then the slag will primarily consist of perovskite and argillaceous iron oxide. Therefore, the second-order correction coefficient b is taken as 1.05. Furthermore, the optimized prediction models for the carbonaceous reducing agent dosage corresponding to each ore sample can be obtained as follows:

[0114] y I =1.05×1.25(-0.1591x+16.488) / 0.885≈20.80kg.

[0115] y II =1.05×1.13(-0.1591x+16.488) / 0.885≈14.08kg.

[0116] y III =1.05×1.10(-0.1591x+16.488) / 0.885≈12.76kg.

[0117] y IV =1.05×1.04(-0.1591x+16.488) / 0.885≈6.95kg.

[0118] Based on the above calculation results, different furnace charges were prepared according to Table 4 below. Each furnace charge was then fed into the electric furnace for deep smelting and reduction according to the proposed deep reduction conditions described above, and the product quality and residual carbon content were tested.

[0119]

[0120] The above are merely preferred embodiments of the present invention. Any equivalent or substantially equivalent substitutions made without departing from the overall inventive concept of the present invention shall fall within the protection scope claimed by the present invention.

Claims

1. A method for controlling the dosage of carbonaceous reducing agent in the deep reduction of vanadium-titanium magnetite, characterized in that: The method for controlling the dosage of carbonaceous reducing agent includes the following steps: S1. Based on the changes in the compositional characteristics of the vanadium-titanium magnetite to be reduced and the flux, a preliminary prediction model for the amount of carbonaceous reducing agent based on the changes in the metallization rate of vanadium-titanium magnetite is established. S2. Based on the changes in flux type coupled with the preliminary prediction model, an optimized prediction model for the amount of carbonaceous reducing agent based on the changes in the metallization rate and slag type of vanadium-titanium magnetite was established. S3. The actual amount of carbonaceous reducing agent used in the deep reduction of vanadium-titanium magnetite in an electric furnace is calculated using the obtained optimized prediction model.

2. The method for controlling the dosage of carbonaceous reducing agent according to claim 1, characterized in that: Step S1 includes: S101. Mix the vanadium-titanium magnetite to be reduced with flux to obtain a mixture, and perform component analysis on the mixture to obtain the content data of each oxide in the mixture; S102. Calculate the theoretical carbon consumption required for the reduction of the current mixture based on the content data of each oxide in the mixture. S103. Based on the theoretical carbon consumption and the residual amount of each oxide and carbon under the working conditions, the required actual carbon consumption and the corresponding actual amount of carbonaceous reducing agent are calculated. S104. Mix the vanadium-titanium magnetite with different metallization rates to be reduced with flux to obtain a mixture. Repeat steps S101 to S103 to obtain the actual amount of carbonaceous reducing agent required for the mixture with different metallization rates, and then establish a preliminary prediction model for the amount of carbonaceous reducing agent based on the change in the metallization rate of vanadium-titanium magnetite.

3. The method for controlling the dosage of carbonaceous reducing agent according to claim 2, characterized in that: In step S101, the oxide includes, but is not limited to, at least one of FeO, Fe2O3, V2O5, SiO2, TiO2, CaO, MgO, and Al2O3, preferably FeO, Fe2O3, V2O5, and SiO2.

4. The method for controlling the dosage of carbonaceous reducing agent according to claim 2 or 3, characterized in that: In step S103, the residual conditions of each oxide and carbon specifically include: When the designed reduction temperature of the electric furnace is 1450~1700℃ and the smelting time is 3~6h: the residual TFe in the slag is less than 2.5% (preferably 0.4~2.2%), the residual V2O5 in the slag is less than 20% (preferably 3~15%), and the residual SiO2 in the slag is greater than 95% (preferably greater than 97%); the residual carbon content in the molten iron does not exceed 4% of the total mass of the molten iron (preferably 1~3%); and the residual carbon content in the slag does not exceed 0.5% of the total mass of the slag (preferably 0.1~0.3%).

5. The method for controlling the dosage of carbonaceous reducing agent according to any one of claims 1-4, characterized in that: The preliminary prediction model is as follows: y0=a(-kx+c) / r (1; In equation (1), y0 is the preliminary predicted value of the amount of carbonaceous reducing agent, kg / 100kg-vanadium-titanium ore; x is the metallization rate of the vanadium-titanium magnetite to be reduced, % a is the first-order correction coefficient, ranging from 1 to 1.3; k is the operating condition coefficient, ranging from 0.15 to 0.19; c is the operating condition constant, ranging from 10 to 20; r is the fixed carbon content of the carbonaceous reducing agent.

6. The method for controlling the dosage of carbonaceous reducing agent according to any one of claims 1-5, characterized in that: The optimized prediction model is as follows: y0=b[a(-kx+c)] / r (2; In equation (2), y0 is the preliminary predicted value of the amount of carbonaceous reducing agent, kg / 100kg-vanadium-titanium ore; x is the metallization rate of the vanadium-titanium magnetite to be reduced, % 'a' is a first-order correction coefficient, with a value ranging from 1 to 1.3; b is the second-order correction coefficient, ranging from 1 to 1.15; k is the operating condition coefficient, ranging from 0.15 to 0.19; c is the operating condition constant, ranging from 10 to 20; r is the fixed carbon content of the carbonaceous reducing agent.

7. The method for controlling the dosage of carbonaceous reducing agent according to claim 5 or 6, characterized in that: Based on the change in the ratio of metallic iron content to total iron content in the vanadium-titanium magnetite to be reduced, the actual metallization rate x of different vanadium-titanium magnetites to be reduced is obtained, and then: When x < 30%, a in equations (1)-(2) ∈ (1.15, 1.30]; When 30%≤x≤60%, a∈[1.07,1.15] in equations (1)-(2); When 60% < x, a ∈ [1.0, 1.07] in equations (1)-(2).

8. The method for controlling the dosage of carbonaceous reducing agent according to claim 6 or 7, characterized in that: In step S2, the flux is a mixed flux consisting of a calcium-containing flux and a silicon-containing flux, or a mixed flux consisting of a magnesium-containing flux and a silicon-containing flux; Preferably, the silicon-containing flux is silicon oxide and / or silicon oxide-containing minerals; the calcium-containing flux is calcium oxide and / or calcium-containing minerals; and the magnesium-containing flux is magnesium oxide and / or magnesium-containing minerals.

9. The method for controlling the dosage of carbonaceous reducing agent according to claim 8, characterized in that: When the flux is a mixture of calcium-containing flux and silicon-containing flux, the amount of flux added is such that the basicity of the mixture is 0.8~1.4; in formula (2), b∈[1.0, 1.1]; When the flux is a mixture of magnesium-containing flux and silicon-containing flux, the amount of flux added is such that the basicity of the mixture is 0.4~1.0; in formula (2), b∈[1.05, 1.15].

10. The method for controlling the dosage of carbonaceous reducing agent according to any one of claims 1-9, characterized in that: The vanadium-titanium magnetite to be reduced is derived from pre-reduced vanadium-titanium magnetite from a rotary kiln and / or a gas-based vertical shaft furnace; preferably, the particle size of the vanadium-titanium magnetite to be reduced is 5~25mm; and / or The carbonaceous reducing agent includes at least one of pulverized coal, charcoal powder, and coke powder; preferably, the particle size of the carbonaceous reducing agent is 5-15 mm.

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