A comprehensive utilization method of vanadium-titanium magnetite

Abstract

The application belongs to the technical field of steel smelting, and specifically discloses a comprehensive utilization method of vanadium-titanium magnetite, which comprises the following steps: S1, preparing vanadium-titanium magnetite into pellets and performing a reduction reaction to obtain direct reduced iron; S2, mixing carbonaceous reducing agent and the direct reduced iron obtained in the step S1, and performing smelting in a melting separation electric furnace to obtain molten slag and molten iron; no slagging agent is added in the smelting process, and the melting separation electric furnace is optimized in design, and various smelting process control means are combined to improve the purity of titanium slag, solve the problems of excessive erosion and low service life of the refractory material of the melting separation electric furnace, difficult separation of slag and gold, and difficult smelting control, and achieve the target of high-grade titanium slag and long service life of the melting separation electric furnace.

Description

Technical Field

[0001] This application relates to the field of iron and steel smelting technology, and in particular to a method for the comprehensive utilization of vanadium-titanium magnetite. Background Technology

[0002] Vanadium-titanium magnetite, an important strategic mineral resource in my country, is currently mainly processed using the traditional blast furnace-converter process. While this process offers advantages in large-scale production, the blast furnace typically adds ordinary ore and lime in proportion when processing vanadium-titanium magnetite, resulting in TiO2 content in the produced titanium slag of only 20%–25%. This leads to large stockpiles of titanium slag that are difficult to utilize effectively, resulting in significant resource waste. Non-blast furnace ironmaking processes, which eliminate the need for coking and sintering steps, offer significant carbon emission reduction advantages and are attracting increasing attention, demonstrating a broader development prospect.

[0003] While the utilization of titanium slag in the smelting process is economically viable, the process suffers from severe furnace lining erosion and significantly impacts the composition and properties of the slag. Furthermore, the rapid decrease in FeO content and increased viscosity during reduction, coupled with improper temperature and carbon composition, can easily lead to an increase in Ti(C,N) content, further deteriorating slag fluidity, resulting in poor slag-iron separation, difficulty in controlling the smelting process, and ultimately, an unstable V recovery rate of over 80% and a stable Ti recovery rate of over 96% in the molten iron. This also results in a short lifespan for the smelting electric furnace. Summary of the Invention

[0004] In view of the shortcomings of the prior art described above, the purpose of this application is to provide a comprehensive utilization method for vanadium-titanium magnetite, which can improve the purity of titanium slag by optimizing the design of the melting electric furnace type and combining various smelting process control methods without slag adjustment. This solves the problems of excessive erosion of refractory materials and short service life of the melting electric furnace, difficulty in slag-gold separation and difficulty in smelting control, and achieves the goal of high-grade titanium slag and long service life of the melting electric furnace.

[0005] To achieve the above and other related objectives, this application provides a method for the comprehensive utilization of vanadium-titanium magnetite, comprising the following steps:

[0006] S1. Vanadium-titanium magnetite is made into pellets and then subjected to a reduction reaction to obtain direct reduced iron;

[0007] S2. Mix the carbonaceous reducing agent and the direct reduced iron obtained in step S1, and smelt them in a melting furnace to obtain slag and molten iron.

[0008] The smelting process does not add slagging agents and performs at least one of the following operations: A to D:

[0009] Operation A: During the design phase, by adjusting the furnace type parameters, the location of the material drop point in the furnace chamber, and the cooling water parameters of the melting furnace, the slag temperature and molten iron temperature on the inner wall of the furnace chamber are controlled within a preset range to form a condensed slag layer and a condensed iron layer for protecting the furnace lining.

[0010] Operation B: During the production stage, by controlling the feeding parameters and power supply parameters, a high-temperature active zone and a low-temperature flow dead zone are formed. The flowability of slag and gold in the high-temperature active zone is controlled to meet the preset requirements, and the temperature of the low-temperature flow dead zone is controlled within the preset range. The high-temperature active zone is the molten pool area enclosed between the material pile and the electrode in the furnace, and the low-temperature flow dead zone is the molten pool area outside the high-temperature active zone.

[0011] Operation C: During the production stage, obtain the real-time status of the foam residue and adjust the power supply parameters based on the real-time status of the foam residue so that the status of the foam residue is maintained or restored to the preset state.

[0012] Operation D: During the production stage, based on the mass-energy balance model of the smelting electric furnace and the collected furnace charge parameters and slag parameters, determine the vanadium recovery rate ηV in the molten iron.

[0013] Based on ηV and the FeO content in the slag, combined with the orientation of vanadium, the average temperature of the high-temperature active zone during the smelting process is controlled within a preset range, and the timing of slag tapping and iron tapping is determined to obtain slag and molten iron.

[0014] Furthermore, operation A includes the following steps:

[0015] A1. Establish a simulation model of the melting and separating electric furnace;

[0016] A2. The simulation model of the melting furnace is divided into grids, and the flow field and temperature field distribution of the molten pool are obtained by coupled solution of the continuity equation, momentum equation and energy equation. Then, the slag temperature and molten iron temperature on the inner wall of the furnace are extracted from them.

[0017] A3. If the extracted slag temperature and molten iron temperature on the inner wall of the furnace exceed the preset range, the furnace type parameters, the location of the material drop point in the furnace, and the cooling water parameters of the smelting electric furnace are adjusted to rebuild the simulation model of the smelting electric furnace, and step A2 is repeated until the extracted slag temperature and molten iron temperature on the inner wall of the furnace are controlled within the preset range.

[0018] Furthermore, in step A1, the input parameters for establishing the simulation model of the smelting electric furnace include: furnace area, thermal conductivity of furnace lining and shell, furnace wall thickness, cooling water parameters, slag production, molten iron production, and iron retention.

[0019] Furthermore, the power supply is determined based on the smelting power consumption and the direct reduced iron consumption, and the furnace area is determined based on the power supply and furnace power density.

[0020] Furthermore, the smelting power consumption is obtained through the mass-energy balance model of the smelting electric furnace. The input parameters for constructing the mass-energy balance model of the smelting electric furnace include the composition and temperature of the direct reduction iron, the composition and temperature of the carbonaceous reducing agent, the degree of reduction of the metal oxide, the initial heat loss parameters of the smelting electric furnace, and the smelting temperature.

[0021] Furthermore, the feeding parameters include the feeding speed, and the power supply parameters include the power supply power;

[0022] Operation B further includes:

[0023] Real-time data from the production phase is acquired, and a neural network model is established that couples the molten slag temperature on the furnace inner wall, the feeding rate, and the power supply. The feeding rate is then dynamically controlled based on the molten slag temperature on the furnace inner wall and the power supply.

[0024] Furthermore, the method of dynamically controlling the feeding speed based on the power supply and the temperature of the molten slag on the inner wall of the furnace includes: when the power supply is constant, if the temperature of the molten slag on the inner wall of the furnace is higher than the first preset molten slag temperature value, the feeding speed is increased by the first preset range; if the temperature of the molten slag on the inner wall of the furnace is lower than the second preset molten slag temperature value, the feeding speed is decreased by the first preset range.

[0025] Furthermore, in operation C, the preset state of the foam residue includes the preset height of the foam residue;

[0026] If the real-time height of the foam residue exceeds the preset height range, the power supply will be reduced by the second preset amount until the height of the foam residue returns to the preset height.

[0027] Furthermore, in operation D, the input parameters for constructing the mass-energy balance model of the smelting electric furnace include the composition and temperature of the direct reduced iron, the composition and temperature of the carbonaceous reducing agent, the degree of reduction of the metal oxide, the initial heat loss parameters of the smelting electric furnace, and the smelting temperature.

[0028] Furthermore, in operation D,

[0029] When the vanadium element is directed towards molten iron, the average temperature of the high-temperature active zone in the initial stage of smelting is controlled within the first preset smelting temperature range; as smelting proceeds, when the FeO content in the slag decreases to the preset FeO content range, the average temperature of the high-temperature active zone in the initial stage of smelting is increased to the second preset smelting temperature range.

[0030] When the vanadium element is slag, the average temperature of the high-temperature active zone during the smelting process is controlled within the third preset smelting temperature range.

[0031] Furthermore, in operation D,

[0032] When the vanadium element is directed towards molten iron and ηV is greater than the first preset ηV value, slag and iron are tapped, and the resulting slag and molten iron are titanium slag and vanadium-containing molten iron, respectively.

[0033] When the vanadium element is directed towards the slag and ηV is less than the second preset ηV value, and the FeO content in the slag decreases to the preset FeO content range, the slag and iron are tapped, and the obtained slag and molten iron are vanadium-titanium slag and low-carbon molten iron, respectively.

[0034] Furthermore, the method also includes step S3, post-processing the slag and molten iron.

[0035] As described above, the comprehensive utilization method of vanadium-titanium magnetite in this application has the following beneficial effects:

[0036] This application uses only carbonaceous reducing agents and direct reduced iron in the smelting process, without adding additional slag-forming agents. Simultaneously, following the above operation, the furnace design of the smelting electric furnace is optimized during the design phase. During the production phase, various methods are used to control the smelting process, promoting the formation and stability of the condensed slag and condensed iron layers, preventing severe erosion of the furnace lining, achieving the goal of a long furnace life, promoting slag-metal separation, and precisely and effectively controlling the smelting process to ensure slag purity and improve the TiO2 grade of the slag. The resulting slag TiO2 grade is higher than that of titanium slag produced by existing smelting electric furnaces, which is beneficial for better slag post-processing and higher economic efficiency. This application solves the problems of low furnace lining life, difficult slag-metal separation, and uncontrollable smelting process, as well as the resulting reduction in slag grade, from both the design and production stages, achieving high yields of elements such as iron, vanadium, and titanium. Attached Figure Description

[0037] Figure 1 A schematic diagram of the process flow for the comprehensive utilization method of vanadium-titanium magnetite provided in this application;

[0038] Figure 2 This is a temperature field distribution diagram from Embodiment 1 of this application;

[0039] Figure 3 This is a temperature field distribution diagram in Embodiment 2 of this application. Detailed Implementation

[0040] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. This application can also be implemented or applied through other different specific embodiments. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0041] Numerous details are explored in the following description to provide a more thorough explanation of embodiments of this application; however, it will be apparent to those skilled in the art that embodiments of this application may be practiced without these specific details.

[0042] In this application, unless otherwise stated, the term "multiple" means two or more.

[0043] The character " / " indicates that the objects before and after it are in an "or" relationship. For example, A / B means: A or B.

[0044] The term "and / or" describes an association between objects, indicating that three relationships can exist. For example, A and / or B means: A or B, or A and B.

[0045] First, it should be noted that the furnace structure of a melting electric furnace (taking an electric arc furnace as an example) typically consists of two parts: the outer shell and the furnace lining. The outer shell is usually composed of metal components, including the furnace shell, furnace door, furnace cover, tapping trough, and electrode sealing rings, providing overall support and sealing. The furnace lining is located inside the outer shell and is made of refractory materials (such as refractory bricks and ceramic fibers). It is in direct contact with the molten material and is subject to high-temperature corrosion, and is divided into the furnace wall, furnace bottom, and molten pool.

[0046] Please refer to Figure 1 One embodiment of this application provides a method for the comprehensive utilization of vanadium-titanium magnetite, comprising the following steps:

[0047] S1. Vanadium-titanium magnetite is made into pellets and then subjected to a reduction reaction to obtain direct reduced iron;

[0048] S2. The carbonaceous reducing agent and the direct reduced iron obtained in step S1 are mixed and smelted in a melting furnace. The atmosphere is controlled as a closed reducing atmosphere with a slight positive pressure (<100Pa) inside the furnace to obtain slag and molten iron. The carbonaceous reducing agent is selected from at least one of coke, pulverized coal, semi-coke and biochar, and its dosage is 15~60kg / t, which means that 15~60kg of carbonaceous reducing agent is added per ton of direct reduced iron.

[0049] The smelting process does not add slagging agents and performs at least one of the following operations: A to D:

[0050] Operation A: During the design phase, by adjusting the furnace type parameters, the location of the material drop point in the furnace chamber, and the cooling water parameters of the melting furnace, the temperature of the slag and the temperature of the molten iron on the inner wall of the furnace chamber are controlled within a preset range to form a condensed slag layer and a condensed iron layer for protecting the furnace lining, thereby preventing the refractory material on the inner wall of the furnace chamber from being eroded by the slag and molten iron.

[0051] Operation B: During the production stage, by controlling the feeding parameters and power supply parameters, a high-temperature active zone and a low-temperature flow dead zone are formed. The flowability of slag and gold in the high-temperature active zone is controlled to meet the preset requirements, and the temperature of the low-temperature flow dead zone is controlled within the preset range. The high-temperature active zone is the molten pool area enclosed between the material pile and the electrode in the furnace, and the low-temperature flow dead zone is the molten pool area outside the high-temperature active zone.

[0052] Operation C: During the production stage, obtain the real-time status of the foam residue and adjust the power supply parameters based on the real-time status of the foam residue so that the status of the foam residue is maintained or restored to the preset state.

[0053] Operation D: During the production stage, based on the mass-energy balance model of the smelting electric furnace and the collected furnace charge parameters and slag parameters, determine the vanadium recovery rate ηV in the molten iron.

[0054] Based on ηV and the FeO content in the slag, combined with the orientation of vanadium, the average temperature of the high-temperature active zone during the smelting process is controlled within a preset range, and the timing of slag tapping and iron tapping is determined to obtain slag and molten iron.

[0055] The embodiments described in this application employ a non-slag-adjusting method during the smelting process. Simultaneously, the furnace design of the smelting electric furnace is optimized during the design phase according to the aforementioned operations. During the production phase, various methods are used to control the smelting process, preventing severe erosion of the furnace lining, achieving the goal of a long service life for the smelting electric furnace, promoting slag-gold separation, precisely and effectively controlling the smelting process, ensuring the purity of the slag, and improving the TiO2 grade of the slag. The resulting slag TiO2 grade is higher than that of titanium slag produced by existing smelting electric furnaces, which is beneficial for better slag post-processing and achieving higher economic efficiency, resulting in high yields of elements such as iron, vanadium, and titanium.

[0056] Among them, optimizing the furnace design parameters during the design phase is beneficial to forming a condensed slag layer and a condensed iron layer for protecting the furnace lining. This avoids problems such as short furnace lining life, corrosion of the refractory material on the inner wall of the furnace leading to titanium slag contamination, and the resulting reduction in slag grade from the design phase.

[0057] By controlling the charging and power supply parameters, the molten pool area is constructed into a high-temperature active zone and a low-temperature dead zone. The arc light is absorbed by the charge pile, keeping the arc close to the slag surface during smelting. This improves energy utilization while maintaining good slag-gold fluidity in the high-temperature active zone, ensuring favorable kinetic conditions for efficient slag-gold separation. Furthermore, by controlling the temperature of the low-temperature dead zone, a temperature gradient is created in the slag along the inner wall of the furnace, lowering the temperature near the furnace wall. This ensures that the slag temperature in contact with the refractory material is below the slag's melting point, facilitating the formation of a condensed slag layer and a condensed iron layer. These operations effectively solve the problems of difficult slag-gold separation, uncontrollable smelting process, short furnace lining life, and the resulting reduction in slag grade from the production stage.

[0058] The power supply parameters are adjusted based on the real-time status of the foam slag to maintain or restore the state of the foam slag to a preset state, thus avoiding problems such as excessive overflow of foam slag affecting the smelting process.

[0059] Based on the mass-energy balance model of the smelting electric furnace and the collected furnace charge and slag parameters, the vanadium yield ηV in the molten iron is determined. Then, based on ηV and the FeO content in the slag, combined with the vanadium element orientation, controlled smelting is carried out for different process routes. This can solve the difficulties in slag-gold separation and the difficulty in controlling the smelting process, while improving the yield of resources such as Fe, V, and Ti, and achieving precise control of the smelting process.

[0060] In some embodiments of this application, operation A includes the following steps:

[0061] A1. Establish a simulation model of the melting and separating electric furnace;

[0062] A2. The simulation model of the melting furnace is divided into grids, and the flow field and temperature field distribution of the molten pool are obtained by coupled solution of the continuity equation, momentum equation and energy equation. Then, the slag temperature and molten iron temperature on the inner wall of the furnace are extracted from them.

[0063] A3. If the extracted slag temperature and molten iron temperature on the inner wall of the furnace exceed the preset range, the furnace type parameters, the location of the material drop point in the furnace, and the cooling water parameters of the smelting furnace are adjusted to rebuild the simulation model of the smelting furnace. Step A2 is then repeated until the extracted slag temperature and molten iron temperature on the inner wall of the furnace are controlled within the preset range. The preset ranges for the slag temperature and molten iron temperature on the inner wall of the furnace are, for example, ≤1350℃ and ≤1200℃, respectively, which can be calculated from the temperature detected by the thermocouples installed on the furnace wall, the thermal conductivity of the refractory material, and the distance between the measuring point and the furnace wall. The furnace type parameters include, but are not limited to, the length, width, and thickness of the outer shell and lining of the smelting furnace. The distance between the material drop point in the furnace and the electrode center is, for example, less than or equal to 600mm, which refers to the horizontal straight-line distance. The cooling water parameters include, but are not limited to, the cooling water flow rate and the temperature difference between the inlet and outlet cooling water, with the temperature difference between the inlet and outlet cooling water being, for example, 15~25℃.

[0064] Furthermore, in some embodiments of this application, the input parameters for establishing the simulation model of the smelting electric furnace in step A1 include: furnace area, thermal conductivity and geometric dimensions of the furnace lining and shell, cooling water parameters, slag production, molten iron production, and residual iron amount. The furnace area refers to the effective area of ​​the inner wall of the furnace, i.e., the area within the furnace where smelting can take place. The thermal conductivity of the furnace lining and shell refers to the thermal conductivity of the refractory material of the furnace lining and the thermal conductivity of the shell material. The geometric dimensions of the furnace lining and shell include the length, width, and thickness parameters of the refractory material of the furnace lining and the shell. The slag production refers to the amount of slag produced per unit time during the smelting process, preferably the hourly slag production, typically measured in tons per hour. The molten iron production refers to the amount of molten iron produced per unit time during the smelting process, preferably the hourly molten iron production, typically measured in tons per hour. The residual iron amount refers to the amount of molten iron retained in the furnace after smelting. The geometric dimension parameters are used to establish the three-dimensional geometric model of the smelting electric furnace, and the physical property parameters, such as thermal conductivity, are used to calculate the temperature field of the molten pool.

[0065] Furthermore, in some embodiments of this application, the power supply is determined based on the smelting power consumption and the direct reduced iron (DRI) consumption, and the furnace area is determined based on the power supply and furnace power density. The DRI consumption refers to the weight of DRI consumed during the smelting process to produce one unit of qualified molten steel, preferably the hourly DRI consumption, typically expressed in tons per hour. The furnace area is the ratio of the power supply to the furnace power density. The furnace power density is, for example, 0.3~0.5 MW / m². 2 .

[0066] Furthermore, in some embodiments of this application, the smelting power consumption is calculated using a mass-energy balance model for a melting electric furnace. This model is a core tool in metallurgical engineering for analyzing and optimizing the operation of melting electric furnaces. Based on the two fundamental principles of conservation of mass and energy, it quantifies the input-output relationship of matter and energy through mathematical modeling, thereby guiding process optimization, energy consumption control, and production management. The input parameters for constructing the mass-energy balance model include, but are not limited to, the composition and temperature of direct reduced iron (DRI), the composition and temperature of the carbonaceous reducing agent, the degree of reduction of the metal oxide, the initial heat loss parameters of the melting electric furnace, and the smelting temperature. The composition of DRI refers to the elemental and compound components and their proportions added to the melting electric furnace, and the temperature of DRI refers to the temperature at which the DRI is added to the melting electric furnace. The composition of the carbonaceous reducing agent refers to the elemental and compound components and the proportion of each component added to the smelting electric furnace. The temperature of the carbonaceous reducing agent refers to the temperature at which it is added to the smelting electric furnace. Metal oxides include, but are not limited to, oxides of metallic elements such as iron, vanadium, and titanium found in vanadium-titanium magnetite. The degree of reduction refers to the extent to which these metal oxides are reduced in direct reduced iron, expressed as a percentage (%). Initial smelting electric furnace heat loss parameters include, but are not limited to, cooling water flow rate, cooling water inlet and outlet temperature difference, and cooling water specific heat capacity. The smelting electric furnace mass-energy balance model in Operation D refers to the smelting electric furnace mass-energy balance model used to calculate smelting power consumption. Specifically, based on these input parameters, according to basic metallurgical principles and the principle of conservation of elements, the amount of products (slag, molten iron, flue gas) generated can be calculated first based on the raw materials (direct reduced iron, carbonaceous reducing agent) entering the smelting electric furnace. Then, based on the principle of energy conservation, the energy consumption required for smelting can be calculated according to the balance between energy input (electrical energy, sensible heat of raw materials) and energy consumption (sensible heat of products, energy consumption of chemical reaction, heat loss) during the operation of the smelting electric furnace.

[0067] In some embodiments of this application, in operation B, controlling the fluidity of slag-gold in the high-temperature active zone to meet preset requirements means ensuring that the slag-gold maintains good fluidity at all times, including but not limited to controlling the slag viscosity to ≤0.4 Pa·s. This ensures good kinetic conditions in the region, promoting thorough separation of slag and gold. Slag viscosity is an important criterion for judging the fluidity of slag-gold, and it can be obtained through image recognition marking. Image acquisition can be achieved by setting a high-definition camera on the observation port of the furnace cover of the smelting equipment to take pictures and observe the flow state of the slag. The viscosity is determined by the slag flow state. For example, a measurement particle is taken from the picture, and the viscosity value is calculated based on Newton's law of viscosity by measuring the velocity gradient of the particle and combining it with temperature parameters.

[0068] According to Newton's law of viscosity, the shear stress τ is related to the velocity gradient. (Unit: s) -1 The viscosity η is directly proportional to the viscosity. .

[0069] The relationship between viscosity and temperature follows the Arrhenius equation:

[0070]

[0071] in, Let R be the activation energy for viscous flow, R be the gas constant, and T be the absolute temperature.

[0072] Alternatively, the viscosity of the slag can be obtained through sampling tests or by other methods commonly used in the field.

[0073] Furthermore, in some embodiments of this application, in operation B, the temperature of the low-temperature flow dead zone is controlled at ≤1400°C.

[0074] In some embodiments of this application, the charging parameters include the charging rate, which refers to the rate at which the furnace charge (including direct reduced iron and carbonaceous reducing agent) is added to the melting furnace; the power supply parameters include the power supply power, which refers to the total amount of electrical energy input into the furnace per unit time; operation B further includes: acquiring real-time data during the production stage and establishing a neuron model coupling the slag temperature on the furnace wall, the charging rate, and the power supply power. In an exemplary embodiment, the establishment of the neuron model includes: constructing a multi-layer feedforward neural network, the structure of which includes an input layer, 1-2 hidden layers, and an output layer; the input layer is configured with 2 neurons, corresponding to the slag temperature on the furnace wall and the power supply power, respectively; each hidden layer can be configured with multiple neurons (e.g., 2-10), the specific number and the number of neurons per layer need to be determined according to actual needs; the output layer is configured with 1 neuron, corresponding to the charging rate; the multi-layer feedforward neural network is trained to obtain the neuron model.

[0075] The input to the hidden layer neurons is:

[0076]

[0077] in, These are the weights from the i-th neuron in the input layer to the j-th neuron in the hidden layer. It is the bias of the j-th neuron in the hidden layer. It is the linear output of the j-th neuron in the hidden layer.

[0078] The input to the output layer neurons is a weighted sum of the outputs of the hidden layers:

[0079]

[0080] in, It is the weight from the j-th neuron in the hidden layer to the output layer. It is the output of the j-th neuron in the hidden layer. It is the bias of the output layer.

[0081] The final output, i.e., the feeding speed, is .

[0082] The charging speed is dynamically controlled based on the slag temperature on the inner wall of the furnace and the power supply. This maintains the stability of the condensed slag layer and the condensed iron layer, preventing them from fluctuating with furnace conditions, power supply, and charging parameters. It optimizes the functions of the high-temperature active zone and the low-temperature dead zone, prevents refractory material corrosion, further ensures the purity of titanium slag, and improves the grade of titanium slag.

[0083] Furthermore, in some embodiments of this application, the method of dynamically controlling the feeding speed based on the power supply and the temperature of the molten slag on the inner wall of the furnace includes: when the power supply is constant, if the temperature of the molten slag on the inner wall of the furnace is higher than a first preset molten slag temperature value, the feeding speed is increased by a first preset range; if the temperature of the molten slag on the inner wall of the furnace is lower than a second preset molten slag temperature value, the feeding speed is decreased by a first preset range. Wherein, the first preset slag temperature value refers to the upper limit of the slag temperature on the inner wall of the furnace, and its range is, for example, 1420~1470℃, specifically 1420℃, 1430℃, 1440℃, 1450℃, 1460℃, 1470℃, etc.; the second preset slag temperature value refers to the lower limit of the slag temperature on the inner wall of the furnace, and its range is, for example, 1250~1300℃, specifically 1250℃, 1260℃, 1270℃, 1280℃, 1290℃, 1300℃, etc.; the first preset amplitude ranges from 15% to 25%, for example, 15%, 17%, 20%, 22%, 25%, etc. The temperature of the molten slag on the inner wall of the furnace can be controlled by the power supply. Higher power supply increases the charging rate when the temperature reaches its upper limit, as the added furnace charge is generally at room temperature or relatively low, thus lowering the furnace temperature. Conversely, lower power supply decreases the charging rate when the temperature reaches its lower limit, increasing the furnace temperature. This method maintains the molten slag temperature on the inner wall of the furnace within a preset range, thereby maintaining the stability of the condensed slag layer and the condensed iron layer, preventing refractory material erosion and ensuring the quality of the titanium slag.

[0084] In some embodiments of this application, in operation C, the preset state of the foam slag includes a preset height of the foam slag, which can be obtained through image recognition or other methods. If the real-time height of the foam slag exceeds the preset height range, the power supply is reduced by a second preset amplitude until the height of the foam slag returns to the preset height. The preset height range is, for example, when the foam slag overflows to 500mm. The value range of the second preset amplitude is 10% to 30%, for example, 10%, 12%, 15%, 18%, 20%, 22%, 25%, 28%, 30%, etc. Furthermore, when it is detected that the foam slag overflow is too high, an early warning can be issued to remind workers to reduce the power supply. After the power supply is reduced, the molten slag temperature will decrease, and the intensity of the reaction will also decrease, thus reducing the height of the foam slag and restoring it to its original position.

[0085] In some embodiments of this application, in operation D, when the vanadium element flows towards molten iron, the average temperature of the high-temperature active zone in the initial stage of smelting is controlled within a first preset smelting temperature range; as smelting proceeds, when the FeO content in the slag decreases to a preset FeO content range, the average temperature of the high-temperature active zone in the initial stage of smelting is increased to a second preset smelting temperature range; for example, the first preset smelting temperature range is 1450~1550℃, the second preset smelting temperature range is 1550~1630℃, and the preset FeO content range is below 10%.

[0086] When the vanadium element is slag, the average temperature of the high-temperature active zone during the smelting process is controlled within the third preset smelting temperature range; for example, the third preset smelting temperature range is 1450~1500℃.

[0087] In some embodiments of this application, in operation D, when the vanadium element is directed towards molten iron and ηV is greater than a first preset ηV value, slag and iron are discharged, and the obtained molten slag and vanadium-containing molten iron are titanium slag and vanadium-containing molten iron, respectively; for example, the value range of the first preset ηV value is 80%~85%, such as 80%, 81%, 82%, 83%, 84%, 85%, etc.

[0088] When the vanadium element is directed towards the slag and ηV is less than the second preset ηV value, and the FeO content in the slag is reduced to the preset FeO content range, the slag and iron are tapped, and the obtained slag and molten iron are vanadium-titanium slag and low-carbon molten iron, respectively. For example, the value range of the second preset ηV value is 12% to 20%, such as 12%, 15%, 16%, 17%, 18%, 19%, 20%, etc.

[0089] In addition, ηV can be calculated using the following formula:

[0090]

[0091] in, The content of vanadium (V) in the furnace charge. For furnace charge quantity, This represents the vanadium (V) content in the slag. This represents the amount of slag generated.

[0092] Please continue to refer to this. Figure 1 In some embodiments of this application, the method further includes step S3, post-processing the slag and molten iron. The post-processing method varies depending on the smelting process:

[0093] When the resulting slag and molten iron are titanium slag and vanadium-containing molten iron, respectively, the titanium slag is treated with a wet process for titanium extraction, which includes the sulfuric acid process and / or hydrochloric acid process; the vanadium-containing molten iron is fed into a converter for vanadium extraction treatment to obtain vanadium slag and vanadium-free molten iron. The vanadium slag is further used in the production of vanadium products, and the vanadium-free molten iron can be further made into ingots or used in steelmaking and steel product production.

[0094] When the obtained slag and molten iron are vanadium-titanium slag and low-carbon molten iron, respectively: the vanadium-titanium slag is subjected to a wet process for stepwise vanadium and titanium extraction, that is, firstly, vanadium-containing acid leaching solution and titanium-rich material are obtained, and then vanadium pentoxide and titanium slag are obtained separately. The titanium slag is further subjected to a wet process for titanium extraction; the low-carbon molten iron can be further made into ingots or used for steelmaking and steel product production.

[0095] The following specific examples illustrate the present invention in detail. It should also be understood that the following examples are only for specific illustrative purposes and should not be construed as limiting the scope of protection of the present invention. Any non-essential improvements and adjustments made by those skilled in the art based on the above description of the present invention are within the scope of protection of the present invention. The specific process parameters, etc., in the following examples are merely examples within a suitable range; that is, those skilled in the art can make appropriate selections within the appropriate range based on the description herein, and are not intended to be limited to the specific values ​​in the examples below.

[0096] Example 1

[0097] This embodiment provides a comprehensive utilization method for vanadium-titanium magnetite, including the following steps:

[0098] S1. Vanadium-titanium magnetite is made into pellets and then reduced in a gas-based vertical furnace to obtain direct reduced iron.

[0099] S2. The carbonaceous reducing agent and the direct reduced iron obtained in step S1 are mixed and smelted in a melting furnace to obtain slag and molten iron; wherein the carbonaceous reducing agent is coke, and the dosage is 52 kg / t.

[0100] No slagging agent is added during the smelting process. The controlled atmosphere is a closed reducing atmosphere with a slight positive pressure inside the furnace (<100 Pa). The following operations A to D are performed:

[0101] Operation A: During the design phase of the melting and separating electric furnace, the furnace parameters are determined by the raw material consumption parameters, power supply parameters, power density parameters, refractory type and parameters. The furnace parameters are optimized by combining the simulation results of the whole furnace flow field and temperature field, so as to avoid the problem of refractory being eroded and contaminated by titanium slag from the design stage.

[0102] The specific implementation method is as follows:

[0103] First, a mass-energy balance model for the smelting electric furnace was constructed using the composition and temperature of direct reduced iron, the composition and temperature of carbonaceous reducing agent, the reduction degree of iron / vanadium / titanium oxides, the initial heat loss parameters of the smelting electric furnace, and the smelting temperature. The composition of direct reduced iron and carbonaceous reducing agent is shown in Table 1. The reduction degrees of iron, vanadium, and titanium oxides are 99%, 80%, and 96%, respectively. The calculated smelting power consumption is 900 kWh / t of molten iron.

[0104] Table 1. Composition of direct reduced iron and carbonaceous reducing agent

[0105]

[0106] Based on the direct reduced iron consumption of 125 t / h, the calculated power supply is 80 MW. This is calculated according to a furnace power density of 0.3~0.5 MW / m³. 2 Calculate the furnace area. A simulation model of the electric arc furnace is established using the thermal conductivity parameters of the refractory material and outer shell, length, width, and thickness parameters, cooling water parameters, hourly slag production, hourly molten iron production, and iron retention as input parameters. The outer shell is 30m × 15m in length and width, and the temperature difference between the inlet and outlet cooling water is 15~25℃. The model is meshed, and the flow field and temperature field distribution of the molten pool are obtained by coupled solving the continuity equation, momentum equation, and energy equation. The temperature field distribution diagram is shown below. Figure 2 As shown. By adjusting the above parameters, the design of the furnace geometry was optimized. After optimization, the outer shell is 30m × 12m in length and width. The slag temperature and molten iron temperature of the inner wall of the furnace refractory were extracted, with the highest temperatures being 1330℃ and 1230℃, respectively, forming a condensed slag layer and a condensed iron layer to prevent the refractory from being eroded.

[0107] Operation B: In actual production, the electric arc is controlled to be close to the slag surface during smelting by controlling the power supply parameters, thereby improving energy utilization. The distance between the material drop point in the furnace and the electrode center is ≤600mm. By adjusting the feeding and power supply parameters, the material drop point is piled up and forms a high-temperature active zone with the electrode. Within this zone, the slag and gold maintain good fluidity with a viscosity ≤0.4Pa·s, ensuring good kinetic conditions to promote full separation of slag and gold. The molten pool outside the high-temperature active zone is a low-temperature dead zone with a temperature ≤1400℃, which is intended to facilitate the formation of a condensed slag layer and a condensed iron layer.

[0108] Furthermore, to maintain the stability of the condensed slag layer and the condensed iron layer, preventing fluctuations in furnace conditions, power supply, and charging parameters, a neural network model coupling the furnace wall thermocouple temperature, charging rate, and power supply was established based on extensive actual production data. This model allows for dynamic control of the charging rate based on thermocouple temperature and power supply. When the power supply is constant, if the molten slag temperature on the inner wall of the refractory material reaches the upper limit temperature T... max =1470℃, then the feeding rate at the corresponding feeding point increases by 20%, if the slag temperature on the inner wall of the refractory material reaches the lower limit temperature T. min =1280℃, then the feeding speed at the corresponding feeding point is reduced by 20%. By controlling the feeding method, the functions of the above high-temperature active zone and low-temperature flow dead zone are optimized, maintaining the condensed slag layer and condensed iron layer, so that the refractory material is not corroded, further ensuring the purity of titanium slag and improving the grade of titanium slag.

[0109] Operation C: To ensure smooth furnace operation, the observation port on the furnace cover of the smelting equipment is equipped with a high-definition camera. The camera identifies foamy slag through image recognition. If the foamy slag overflows to a height of 500mm, an early warning is issued, and the operator reduces the power supply by 10% to 30% until the foamy slag returns to its original position.

[0110] Operation D: Obtain slag samples from the high-temperature active zone using an automatic temperature sampling device and detect the FeO and V2O5 content. Combining this with the mass-energy balance model of the smelting electric furnace from step 3, input the collected data for the furnace charge parameters and slag parameters, and further calculate the V recovery rate ηV from the molten iron.

[0111] The average temperature in the initial high-temperature active zone was controlled at 1450~1550℃. As smelting progressed, the FeO content in the slag gradually decreased; the FeO content and ηV were assessed. When the FeO content was first detected to be <10%, the temperature gradually increased to 1550~1630℃. As reduction continued, when the V₂O₅ content was first detected to be 0.53% (ηV>80%), slag and iron could be tapped. The obtained slag and molten iron were titanium slag and vanadium-containing molten iron, respectively. Due to Ti(C,N) <2% in the slag, the slag-metal separation and reduction effects were good. The Ti recovery rate in the titanium slag was 96.2%, the Fe recovery rate in the molten iron was 99.5%, and the V recovery rate was 80.5%. The TiO₂ grade of the slag was 44%.

[0112] S3. Post-process the obtained slag and molten iron:

[0113] Titanium slag is treated with a wet process for titanium extraction, specifically using either the sulfuric acid method or the hydrochloric acid method. Vanadium-containing molten iron is then processed in a converter to extract vanadium, resulting in vanadium slag and vanadium-free molten iron. The vanadium slag is further used in the production of vanadium products, while the vanadium-free molten iron can be further processed into ingots or used in steelmaking and steel product production.

[0114] Example 2

[0115] This embodiment provides a comprehensive utilization method for vanadium-titanium magnetite, including the following steps:

[0116] S1. Vanadium-titanium magnetite is made into pellets and then subjected to a reduction reaction in a gas-based vertical shaft furnace to obtain direct reduced iron.

[0117] S2. The carbonaceous reducing agent and the direct reduced iron obtained in step S1 are mixed and smelted in a melting furnace to obtain slag and molten iron; wherein the carbonaceous reducing agent is coke, and the dosage is 25 kg / t.

[0118] No slagging agent is added during the smelting process. The controlled atmosphere is a closed reducing atmosphere with a slight positive pressure inside the furnace (<100 Pa). The following operations A to D are performed:

[0119] Operation A: During the design phase of the melting and separating electric furnace, the furnace parameters are determined by the raw material consumption parameters, power supply parameters, power density parameters, refractory type and parameters. The furnace parameters are optimized by combining the simulation results of the whole furnace flow field and temperature field, so as to avoid the problem of refractory being eroded and contaminated by titanium slag from the design stage.

[0120] The specific implementation method is as follows:

[0121] First, a mass-energy balance model for the smelting electric furnace was constructed using the composition and temperature of direct reduced iron, the composition and temperature of carbonaceous reducing agent, the reduction degree of iron / vanadium / titanium oxides, the initial heat loss parameters of the smelting electric furnace, and the smelting temperature. The composition of direct reduced iron and carbonaceous reducing agent is shown in Table 2. The reduction degrees of iron, vanadium, and titanium oxides are 96%, 80%, and 98%, respectively. The calculated smelting power consumption is 860 kWh / t of molten iron.

[0122] Table 2 Composition of Direct Reduced Iron and Carbonaceous Reducing Agent

[0123]

[0124] Further combining this with the direct reduced iron hourly consumption of 2 t / h, the calculated power supply is 1160 kW. Based on a furnace power density of 0.3~0.5 MW / m³, this is calculated. 2 The furnace area was calculated. A simulation model of the electric arc furnace was established using the thermal conductivity parameters of the refractory material and outer shell, length, width, and thickness parameters, cooling water parameters, hourly slag production, hourly molten iron production, and iron retention as input parameters. The outer shell is 5.8m × 3m in length and width, and the temperature difference between the inlet and outlet cooling water is 15~25℃. The model was meshed, and the flow field and temperature field distribution of the molten pool were obtained by coupled solving the continuity equation, momentum equation, and energy equation. The temperature field distribution diagram is shown below. Figure 3As shown. By adjusting the above parameters, the design of the furnace geometry was optimized. After optimization, the outer shell is 5.8m long and 3.2m wide. The slag temperature and molten iron temperature of the inner wall of the furnace refractory were extracted, with the highest temperatures being 1335℃ and 1200℃, respectively, forming a condensed slag layer and a condensed iron layer to prevent the refractory from being eroded.

[0125] Operation B: In actual production, the electric arc is controlled to be close to the slag surface during smelting by controlling the power supply parameters, thereby improving energy utilization. The distance between the material drop point in the furnace and the electrode center is ≤600mm. By adjusting the feeding and power supply parameters, the material drop point is piled up and forms a high-temperature active zone with the electrode. Within this zone, the slag and gold maintain good fluidity with a viscosity ≤0.4Pa·s, ensuring good kinetic conditions to promote full separation of slag and gold. The molten pool outside the high-temperature active zone is a low-temperature dead zone with a temperature ≤1400℃, which is intended to facilitate the formation of a condensed slag layer and a condensed iron layer.

[0126] Furthermore, to maintain the stability of the condensed slag layer and the condensed iron layer, preventing fluctuations in furnace conditions, power supply, and charging parameters, a neural network model coupling the furnace wall thermocouple temperature, charging rate, and power supply was established based on extensive actual production data. This model allows for dynamic control of the charging rate based on thermocouple temperature and power supply. When the power supply is constant, if the molten slag temperature on the inner wall of the refractory material reaches the upper limit temperature T... max =1420℃, then the feeding rate at the corresponding feeding point increases by 20%, if the slag temperature on the inner wall of the refractory material reaches the lower limit temperature T. min =1250℃, then the feeding rate at the corresponding feeding point is reduced by 20%. By controlling the feeding method, the functions of the above high-temperature active zone and low-temperature flow dead zone are optimized, maintaining the condensed slag layer and condensed iron layer, so that the refractory material is not corroded, further ensuring the purity of titanium slag and improving the grade of titanium slag.

[0127] Operation C: To ensure smooth furnace operation, the observation port on the furnace cover of the smelting equipment is equipped with a high-definition camera. The camera identifies foamy slag through image recognition. If the foamy slag overflows to a height of 500mm, an early warning is issued, and the operator reduces the power supply by 10% to 30% until the foamy slag returns to its original position.

[0128] Operation D: Obtain slag samples from the high-temperature active zone using an automatic temperature sampling device and detect the FeO and V2O5 content. Combining this with the mass-energy balance model of the smelting electric furnace from Operation A, input the collected data for the furnace charge parameters and slag parameters, and further calculate the V recovery rate ηV from the molten iron.

[0129] The average temperature in the initial stage of the high-temperature active zone is controlled at 1450~1500℃. As smelting progresses, when both ① and ② are simultaneously met for the first time: ① FeO content <10%; ② ηV <15%, slag and iron can be tapped. The slag contains almost no Ti (C,N), resulting in good slag-metal separation and reduction. The obtained molten slag and molten iron are vanadium-titanium slag and low-carbon molten iron, respectively. The Ti recovery rate in the titanium slag is 98.1%, the Fe recovery rate in the molten iron is 96.5%, and the V recovery rate is 80.5%. The TiO2 grade of the molten slag is 45%.

[0130] S3. Post-processing of the slag and molten iron:

[0131] Vanadium-titanium slag is processed using a wet process to extract vanadium and titanium in stages. First, vanadium-containing acid leaching solution and titanium-rich material are obtained, and then vanadium pentoxide and titanium slag are obtained separately. The titanium slag is further processed using a wet process to extract titanium. The low-carbon molten iron can be further made into ingots or used in steelmaking and steel product production.

[0132] The above embodiments are merely illustrative of the principles and effects of this application and are not intended to limit this application. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this application. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this application should still be covered by the claims of this application.

Claims

1. A method for the comprehensive utilization of vanadium-titanium magnetite, characterized in that, Includes the following steps: S1. Vanadium-titanium magnetite is made into pellets and then subjected to a reduction reaction to obtain direct reduced iron; S2. Mix the carbonaceous reducing agent and the direct reduced iron obtained in step S1, and smelt them in a melting furnace to obtain slag and molten iron. The smelting process does not add slagging agents and performs at least one of the following operations: A to D: Operation A: During the design phase, by adjusting the furnace type parameters, the location of the material drop point in the furnace chamber, and the cooling water parameters of the melting furnace, the slag temperature and molten iron temperature on the inner wall of the furnace chamber are controlled within a preset range to form a condensed slag layer and a condensed iron layer for protecting the furnace lining. Operation B: During the production stage, by controlling the feeding parameters and power supply parameters, a high-temperature active zone and a low-temperature flow dead zone are formed. The flowability of slag and gold in the high-temperature active zone is controlled to meet the preset requirements, and the temperature of the low-temperature flow dead zone is controlled within the preset range. The high-temperature active zone is the molten pool area enclosed between the material pile and the electrode in the furnace, and the low-temperature flow dead zone is the molten pool area outside the high-temperature active zone. The feeding parameters include the feeding speed, and the power supply parameters include the power supply power. Operation B further includes: Real-time data from the production stage is acquired, and a neural network model is established that couples the molten slag temperature on the inner wall of the furnace with the feeding rate and the power supply. The feeding rate is then dynamically controlled based on the molten slag temperature on the inner wall of the furnace and the power supply. Operation C: During the production stage, obtain the real-time status of the foam residue and adjust the power supply parameters based on the real-time status of the foam residue so that the status of the foam residue is maintained or restored to the preset state. In operation C, the preset state of the foam residue includes the preset height of the foam residue; If the real-time height of the foam residue exceeds the preset height range, the power supply will be reduced by the second preset amount until the height of the foam residue returns to the preset height. Operation D: During the production stage, based on the mass-energy balance model of the smelting electric furnace and the collected furnace charge parameters and slag parameters, determine the vanadium recovery rate ηV in the molten iron. Based on ηV and the FeO content in the slag, combined with the orientation of vanadium, the average temperature of the high-temperature active zone during the smelting process is controlled within a preset range, and the timing of slag tapping and iron tapping is determined to obtain slag and molten iron. In operation D, the input parameters for constructing the mass-energy balance model of the melting electric furnace include the composition and temperature of the direct reduction iron, the composition and temperature of the carbonaceous reducing agent, the degree of reduction of the metal oxide, the initial heat loss parameters of the melting electric furnace, and the smelting temperature.

2. The method according to claim 1, characterized in that: Operation A includes the following steps: A1. Establish a simulation model of the melting and separating electric furnace; A2. The simulation model of the melting furnace is divided into grids, and the flow field and temperature field distribution of the molten pool are obtained by coupled solution of the continuity equation, momentum equation and energy equation. Then, the slag temperature and molten iron temperature on the inner wall of the furnace are extracted from them. A3. If the extracted slag temperature and molten iron temperature on the inner wall of the furnace exceed the preset range, the furnace type parameters, the location of the material drop point in the furnace, and the cooling water parameters of the smelting electric furnace are adjusted to rebuild the simulation model of the smelting electric furnace, and step A2 is repeated until the extracted slag temperature and molten iron temperature on the inner wall of the furnace are controlled within the preset range.

3. The method according to claim 2, characterized in that: In step A1, the input parameters for establishing the simulation model of the smelting electric furnace include: furnace area, thermal conductivity of furnace lining and shell, furnace wall thickness, cooling water parameters, slag production, molten iron production, and iron retention.

4. The method according to claim 3, characterized in that: The power supply is determined based on the smelting power consumption and the direct reduced iron consumption, and then the furnace area is determined based on the power supply and the furnace power density.

5. The method according to claim 4, characterized in that: The smelting power consumption was obtained using a mass-energy balance model for a melting electric furnace.

6. The method according to claim 1, characterized in that: The method of dynamically controlling the feeding speed based on the power supply and the temperature of the molten slag on the inner wall of the furnace includes: when the power supply is constant, if the temperature of the molten slag on the inner wall of the furnace is higher than the first preset molten slag temperature value, the feeding speed is increased by the first preset range; if the temperature of the molten slag on the inner wall of the furnace is lower than the second preset molten slag temperature value, the feeding speed is decreased by the first preset range.

7. The method according to claim 1, characterized in that: In operation D... When the vanadium element is directed towards molten iron, the average temperature of the high-temperature active zone in the initial stage of smelting is controlled within the first preset smelting temperature range; as smelting proceeds, when the FeO content in the slag decreases to the preset FeO content range, the average temperature of the high-temperature active zone in the initial stage of smelting is increased to the second preset smelting temperature range. When the vanadium element is slag, the average temperature of the high-temperature active zone during the smelting process is controlled within the third preset smelting temperature range.

8. The method according to claim 1 or 7, characterized in that: In operation D... When the vanadium element is directed towards molten iron and ηV is greater than the first preset ηV value, slag and iron are tapped, and the resulting slag and molten iron are titanium slag and vanadium-containing molten iron, respectively. When the vanadium element is directed towards the slag and ηV is less than the second preset ηV value, and the FeO content in the slag decreases to the preset FeO content range, the slag and iron are tapped, and the obtained slag and molten iron are vanadium-titanium slag and low-carbon molten iron, respectively.

9. The method according to claim 1, characterized in that: The method further includes step S3, which involves post-processing the slag and molten iron.

Images