Apparatus for producing ferro-niobium-titanium alloy and aluminothermic reduction method

Abstract

The present application relates to a kind of equipment and aluminothermic reduction method for producing niobium titanium ferroalloy, belong to niobium titanium ferroalloy production technical field.The equipment for producing niobium titanium ferroalloy includes heating crucible and reaction crucible, the heating crucible is higher than the reaction crucible;The heating crucible is carbon crucible;The reaction crucible is oxide crucible;The heating crucible is used to melt niobium titanium containing slag;The reaction crucible is used to melt iron block and aluminum-iron alloy, and carries out aluminothermic reduction.The present application adopts the design of separate crucible: heating crucible selects carbon crucible (such as graphite crucible) for melting niobium titanium containing slag, and reaction crucible selects oxide crucible (such as alumina, magnesia crucible) for aluminothermic reduction, to ensure the service life of crucible.

Description

Technical Field

[0001] This invention relates to the field of niobium-titanium-iron alloy production technology, and in particular to an equipment for producing niobium-titanium-iron alloy and an aluminothermic reduction method. Background Technology

[0002] Niobium-titanium ferroalloy is a new type of microalloying agent for steelmaking, replacing ferroniobium and ferrotitanium, and is an important raw material for smelting high-strength niobium-containing steel. Common smelting methods for niobium-titanium ferroalloys are divided into carbothermic reduction and aluminothermic reduction. The carbothermic reduction method has the advantage of low smelting cost, but the smelting process is difficult to control, the reduction rate of niobium and titanium is relatively low, and more impurities are introduced by the reducing agent. The aluminothermic reduction method, due to its high reduction rate of niobium and titanium and low product impurities, is a commonly used method for preparing high-end niobium-titanium ferroalloys.

[0003] In the aluminothermic reduction process for preparing high-end niobium-titanium ferroalloys, metallic aluminum is used to reduce metal oxides in molten slag to metal, which is then melted into the ferroalloy. During the aluminothermic reaction, metallic aluminum particles float on top of the niobium-titanium-containing molten slag. The aluminothermic reduction reaction is a violent and exothermic reaction, producing sparks and splashing out high-temperature molten slag and unreacted metallic aluminum. This not only poses safety hazards but also reduces the reduction efficiency of metallic aluminum, resulting in lower niobium and titanium contents in the niobium-titanium ferroalloy. Summary of the Invention

[0004] Based on the above analysis, the present invention aims to provide an equipment and aluminothermic reduction method for producing niobium-titanium ferroalloys, thereby achieving stable production of niobium-titanium ferroalloys with qualified composition using niobium-containing titanium slag as raw material.

[0005] On one hand, the present invention provides an apparatus for producing niobium-titanium-iron alloy, comprising a heating crucible and a reaction crucible, wherein the heating crucible is higher than the reaction crucible; the heating crucible is a carbonaceous crucible; and the reaction crucible is an oxide crucible. The heating crucible is used to melt niobium-containing titanium slag; the reaction crucible is used to melt iron blocks and aluminum-iron alloys and to perform aluminothermic reduction.

[0006] Furthermore, the heating crucible and the reaction crucible are not coaxial, and their axes are parallel to each other.

[0007] Furthermore, it includes a tilting device for rotating the heating crucible and the reaction crucible.

[0008] Furthermore, the heating crucible and the reaction crucible are coaxially arranged.

[0009] Furthermore, the heating crucible has a U-shaped cross-section, a through hole is provided at the bottom of the heating crucible, and a circular control plate is placed inside the heating crucible, with the control plate located on the through hole.

[0010] Furthermore, the diameter of the through hole is 50% to 90% of the diameter of the heating crucible.

[0011] Furthermore, the diameter of the control piece is 110% to 120% of the diameter of the through hole.

[0012] Furthermore, the control plate is made of an iron-carbon alloy, and the carbon content in the iron-carbon alloy is 0.01wt%~1wt%.

[0013] Furthermore, the system includes a tilting device and a vertically sliding moving device. The heating crucible is connected to the moving device, which is used to adjust the distance between the heating crucible and the reaction crucible. The tilting device is connected to the reaction crucible and is used to pour the molten niobium-titanium-iron alloy from the reaction crucible into the ingot mold.

[0014] On the other hand, the present invention provides an aluminothermic reduction method for producing niobium-titanium-iron alloy, which uses the equipment described in the present invention to prepare niobium-titanium-iron alloy; niobium-containing titanium slag is added to a heating crucible; an iron block is added to a reaction crucible; the heating crucible and the reaction crucible are heated to melt the niobium-containing titanium slag and the iron block respectively; then an aluminum-iron alloy is added to the reaction crucible; the melted niobium-containing titanium slag is added to the reaction crucible for aluminothermic reduction to obtain niobium-titanium-iron alloy liquid, which is then cast to obtain the niobium-titanium-iron alloy.

[0015] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects: 1. When using a traditional single crucible, the graphite crucible reacts with the niobium-containing titanium slag at high temperatures to generate high-melting-point niobium carbide and titanium carbide, reducing the niobium and titanium content in the niobium-titanium ferroalloy and increasing the slag viscosity, making slag-metal separation difficult. Furthermore, the oxide crucible, in prolonged contact with the niobium-containing titanium slag at high temperatures, is easily corroded and cracked, severely impacting the reaction success rate and crucible lifespan. This invention employs a separate crucible design: a carbonaceous crucible (such as a graphite crucible) is used for melting the niobium-containing titanium slag, while an oxide crucible (such as an alumina or magnesium oxide crucible) is used for aluminothermic reduction, thus ensuring the crucible's lifespan.

[0016] 2. This method involves melting niobium-titanium slag and iron blocks in stages, adding the aluminum-iron alloy to the reaction crucible, and then adding the molten slag liquid for reduction reaction. This avoids the violent splashing caused by aluminum particles floating on the slag surface in traditional methods, making the reaction process more stable, significantly reducing safety risks, and reducing material loss caused by high-temperature splashing. This, in turn, increases the niobium and titanium content in the obtained niobium-titanium-iron alloy.

[0017] 3. This invention uses molten iron from melted iron blocks as the alloy matrix. The molten iron formed after the iron blocks are melted serves as a highly efficient metal harvester, which can rapidly melt and collect the niobium and titanium metals reduced by the aluminothermic reaction, preventing them from being dispersed in the slag and causing loss, thereby ensuring the niobium and titanium content in the niobium-titanium-iron alloy.

[0018] 4. In traditional methods, aluminum granules are used as a reducing agent. The aluminothermic reduction reaction is a violent and exothermic reaction, which is very dangerous and can only be achieved at the laboratory level, not for industrial production. This invention uses an aluminum-iron alloy as a reducing agent and combines it with a double crucible design, resulting in a stable aluminothermic reduction reaction and achieving a breakthrough from laboratory to industrial levels.

[0019] In addition, by adding iron blocks to form a niobium-titanium-iron alloy, the eutectic effect of iron with niobium and titanium can significantly reduce the overall melting point of the alloy, allowing the alloy to maintain good fluidity at smelting temperatures. This ensures that the alloy and slag can be fully separated after the reaction and smoothly poured out of the reaction crucible, guaranteeing the operability and continuity of the process. It can also reduce the physical corrosion of the crucible by the slag under high-temperature conditions, thereby extending the service life of the crucible.

[0020] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained from what is particularly pointed out in the description and drawings. Attached Figure Description

[0021] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0022] Figure 1 This is a schematic diagram of the aluminothermic reduction production apparatus used in Example 1; Figure 2 This is a schematic diagram of the aluminothermic reduction production apparatus used in Example 2; Figure label: 1. Heating crucible; 2. Reaction crucible; 3. Induction heating device; 4. Tilting device; 5. Moving device; 6. Reaction control plate; 7. Ingot mold. Detailed Implementation

[0023] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0024] Niobium-titanium ferroalloy is a new type of microalloying agent for steelmaking, replacing ferroniobium and ferrotitanium, and is an important raw material for smelting high-strength niobium-containing steel. Common smelting methods for niobium-titanium ferroalloys are divided into carbothermic reduction and aluminothermic reduction. The carbothermic reduction method has the advantage of low smelting cost, but the smelting process is difficult to control, the reduction rate of niobium and titanium is relatively low, and more impurities are introduced by the reducing agent. The aluminothermic reduction method, due to its high reduction rate of niobium and titanium and low product impurities, is a commonly used method for preparing high-end niobium-titanium ferroalloys.

[0025] In the aluminothermic reduction process for preparing high-end niobium-titanium ferroalloys, metallic aluminum is used to reduce metal oxides in molten slag to metal, which is then melted into the ferroalloy. During the aluminothermic reaction, metallic aluminum particles float on top of the niobium-titanium-containing molten slag. The aluminothermic reduction reaction is a violent and exothermic reaction, producing sparks and splashing out high-temperature molten slag and unreacted metallic aluminum. This not only poses safety hazards but also reduces the reduction efficiency of metallic aluminum, resulting in lower niobium and titanium contents in the niobium-titanium ferroalloy.

[0026] Therefore, the present invention provides an apparatus for producing niobium-titanium-iron alloy, comprising a heating crucible and a reaction crucible, wherein the heating crucible is higher than the reaction crucible; the heating crucible is a carbonaceous crucible; and the reaction crucible is an oxide crucible. The heating crucible is used to melt niobium-containing titanium slag; the reaction crucible is used to melt iron blocks and aluminum-iron alloys and to perform aluminothermic reduction.

[0027] Compared to existing technologies, when using a traditional single crucible, the reaction between the graphite crucible and the niobium-containing titanium slag at high temperatures generates high-melting-point niobium carbide and titanium carbide, reducing the niobium and titanium content in the niobium-titanium ferroalloy. This also increases the viscosity of the slag, making slag-metal separation difficult. Furthermore, the oxide crucible's prolonged contact with the niobium-containing titanium slag at high temperatures makes it highly susceptible to corrosion and cracking, severely impacting the reaction success rate and crucible lifespan. This method employs a separate crucible design: a carbonaceous crucible (such as a graphite crucible) is used for melting the niobium-containing titanium slag, while an oxide crucible (such as an alumina or magnesium oxide crucible) is used for aluminothermic reduction, thus ensuring the crucible's lifespan.

[0028] It should be noted that this invention uses two different crucibles: a heating crucible and a reaction crucible. The heating crucible is mainly used to melt niobium-containing titanium slag, while the reaction crucible is used not only to melt iron blocks and aluminum-iron alloys, but also to carry out an aluminothermic reaction.

[0029] In this invention, the heating crucible needs to be higher than the reaction crucible. After the niobium-titanium slag melts in the heating crucible, it needs to be poured into the reaction crucible and then undergoes an aluminothermic reaction to obtain a niobium-titanium-iron alloy, thus ensuring the niobium and titanium content in the niobium-titanium-iron alloy.

[0030] Specifically, the heating crucible and the reaction crucible are arranged coaxially.

[0031] Specifically, the heating crucible and the reaction crucible are non-coaxial.

[0032] It should be noted that when the heating crucible and the reaction crucible are not coaxial, a tilting device is included for rotating the heating crucible and the reaction crucible.

[0033] It should be noted that when the heating crucible and the reaction crucible are coaxially arranged, the cross-section of the heating crucible through the axis is U-shaped, and a through hole is opened at the bottom of the heating crucible. The diameter of the through hole is 50% to 90% of the diameter of the heating crucible.

[0034] Preferably, the diameter of the through hole is smaller than the diameter of the reaction crucible.

[0035] Specifically, a circular control plate is placed inside the heating crucible. The control plate is placed on the through hole, and the diameter of the control plate is 110% to 120% of the diameter of the through hole. The thickness of the control plate is adjusted according to actual needs.

[0036] Preferably, the control plate is made of an iron-carbon alloy, and the carbon content in the iron-carbon alloy is 0.01 wt% to 1 wt%.

[0037] Preferably, the diameter of the control plate is smaller than the diameter of the heating crucible.

[0038] Specifically, when the heating crucible and the reaction crucible are coaxially arranged, the system includes a tilting device and a vertically sliding moving device. The heating crucible is connected to the moving device, which is used to adjust the distance between the heating crucible and the reaction crucible. The tilting device is connected to the reaction crucible and is used to pour the molten niobium-titanium-iron alloy from the reaction crucible into the ingot mold.

[0039] Specifically, when the heating crucible and the reaction crucible are coaxially arranged, a tilting device is included that is connected to the heating crucible and the reaction crucible respectively. The tilting device can tilt the molten niobium-containing titanium slag into the reaction crucible, and at the same time, it can tilt the niobium-titanium-iron alloy liquid in the reaction crucible into the ingot mold.

[0040] It should be noted that both the moving device and the tilting device adopt existing structures. For example, the moving device includes a motor and a gear rack, or other devices capable of achieving the moving function. For example, the tilting device includes a motor and a reducer, or other devices capable of tilting or overturning, which will not be elaborated here.

[0041] In this invention, an induction heating device is used to melt the niobium-titanium slag and iron blocks, and to carry out the aluminothermic reaction. The induction heating device also adopts an existing structure, which can be referenced from the structure of a medium-frequency induction furnace. The induction heating device includes an induction coil, with a heating crucible and a reaction crucible placed inside the induction coil. The heating principle is based on electromagnetic induction, by converting the industrial frequency alternating current into a medium-frequency current, generating an alternating magnetic field in the induction coil, causing eddy currents to be generated inside the crucible, thereby achieving rapid heating.

[0042] This invention provides an aluminothermic reduction method for producing niobium-titanium-iron alloy, comprising the following steps: S1: Add niobium-containing titanium slag to the heating crucible; S2: Add iron blocks to the reaction crucible; S3: Heat the heating crucible and the reaction crucible, melt the niobium-titanium slag and iron block separately, and then add aluminum-iron alloy to the reaction crucible; S4: The molten niobium-containing titanium slag is added to the reaction crucible for aluminothermic reduction to obtain niobium-titanium-iron alloy liquid, which is then cast to obtain niobium-titanium-iron alloy.

[0043] Compared with existing technologies, this method melts niobium-titanium slag and iron blocks in stages, adds aluminum-iron alloy to the reaction crucible, and then adds molten slag liquid for reduction reaction. This avoids the violent splashing caused by aluminum particles floating on the slag surface in traditional methods, making the reaction process more stable, significantly reducing safety risks, and reducing material loss caused by high-temperature splashing. This, in turn, increases the niobium and titanium content in the obtained niobium-titanium-iron alloy.

[0044] It should be noted that the core role of adding iron blocks in the aluminothermic reduction preparation process of niobium-titanium ferroalloys is reflected in the following three aspects: First, the molten iron formed after the iron blocks melt acts as a highly efficient metal collector, rapidly melting and collecting the niobium and titanium metals reduced by the aluminothermic reaction, preventing them from being dispersed in the slag and causing loss, thus ensuring the niobium and titanium content in the niobium-titanium ferroalloy. Second, pure niobium and pure titanium have extremely high melting points, far exceeding the operating temperature range of conventional smelting furnaces. By adding iron blocks to form niobium-titanium ferroalloys, the eutectic effect of iron with niobium and titanium can significantly reduce the overall melting point of the alloy, allowing the alloy to maintain good fluidity at smelting temperatures. This ensures that the alloy can be fully separated from the slag after the reaction and smoothly poured from the reaction crucible, guaranteeing the operability and continuity of the process. In addition, molten iron, as the alloy matrix, helps to dilute and buffer the intense exothermic effect of the aluminothermic reaction, making the reaction process more stable. It also facilitates precise control of the composition ratio of the final product, meeting the microalloying requirements of different steel grades.

[0045] Preferably, the weight of the iron block accounts for 10% to 15% of the weight of the niobium-titanium slag.

[0046] Specifically, the particle size of the niobium-containing titanium slag is 10~80mm.

[0047] It should be noted that in this invention, the particle size of the niobium-containing titanium slag is controlled within 10-80 mm to achieve uniform melting and stable heating of the niobium-containing titanium slag in the heating crucible. If the particle size is too small (e.g., powder), it is easily carried out of the heating crucible by the hot air flow during the heating process; while if the particle size is too large, the gaps between the slag particles will be too large, resulting in insufficient addition of niobium-containing titanium slag and reduced production efficiency.

[0048] Preferably, the niobium-titanium slag is loaded to a height of 40-95% of the height of the heating crucible.

[0049] It should be noted that controlling the charging height of niobium-titanium slag to 40%–95% of the heating crucible height is primarily to achieve a balance between smelting efficiency and operational safety. If the charging amount is too low, below 40%, the single-furnace smelting output will be low, and the heat loss and crucible consumption costs will increase accordingly, reducing economic efficiency. If the charging amount is too high, exceeding 95%, the niobium-titanium slag is prone to violent fluctuations in the molten slag surface during heating and melting due to the escape of gases from the molten slag at high temperatures or localized boiling, posing a risk of overflowing the crucible. This could not only result in raw material loss but also damage the heating equipment or even cause a safety accident.

[0050] Specifically, the binary basicity of the niobium-containing titanium slag is 0.9~1.1.

[0051] It should be noted that controlling the binary basicity of the niobium-titanium slag between 0.9 and 1.1 is primarily based on considerations of crucible lifespan and slag-metal separation efficiency. Niobium-titanium slag itself contains a certain amount of CaO and a large amount of SiO2. If the basicity is too low, the excess SiO2 in the slag will significantly exacerbate the erosion of the alumina reaction crucible at high temperatures, shortening the crucible's lifespan. Simultaneously, the high viscosity of the low-basicity slag is not conducive to complete slag-metal separation, affecting alloy purity. If the basicity is too high, although it can reduce chemical erosion of the crucible, the slag melting point increases with increasing basicity. Excessively high melting point and viscosity will also hinder slag-metal separation, and high-temperature conditions will accelerate the physical erosion of the crucible by the slag.

[0052] This invention achieves suitable slag fluidity and melting point by controlling the basicity within the range of 0.9 to 1.1, which reduces the erosion of the alumina crucible and ensures that the reduced alloy and slag can be fully separated, thereby increasing the niobium and titanium content in the obtained niobium-titanium-iron alloy.

[0053] Specifically, the density of the aluminum-iron alloy is 4.5 g / cm³. 3 ~4.8 g / cm 3 .

[0054] Specifically, the molar ratio of aluminum in the aluminum-iron alloy to oxygen in the niobium oxide and titanium oxide components of the niobium-containing titanium slag is 1:2.4 to 1:2.8.

[0055] It should be noted that the density of metallic aluminum is 2.7 g / cm³. 3 It is much lower than the density of niobium-titanium slag (approximately 3.7~4.0 g / cm³). 3 In actual smelting, metallic aluminum floats on the surface of the molten slag and reacts rapidly, releasing heat. Some of the aluminum reacts with the air to oxidize, while some is melted at high temperatures and splashes out of the furnace. Both of these causes result in the waste of metallic aluminum and make it difficult to control the furnace conditions.

[0056] This invention achieves this by controlling the density of the aluminum-iron alloy to 4.5~4.8 g / cm³. 3 This method ensures good settling and contact conditions for the reducing agent in the molten slag, avoiding the problems of aluminum particles floating on the slag surface and insufficient reaction in traditional methods. Simultaneously, the molar ratio of aluminum in the aluminum-iron alloy to oxygen in the niobium oxide and titanium oxide components of the niobium-titanium slag is limited to 1:2.4~1:2.8 (exemplary, the molar ratio of aluminum to oxygen can be 1:2.4, 1:2.5, 1:2.6, 1:2.7, or 1:2.8). This ensures the reduction effect while avoiding excess or insufficient aluminum, thereby improving the reduction stability of niobium and titanium, reducing alloy composition fluctuations, and ensuring the niobium and titanium content in the niobium-titanium ferroalloy.

[0057] Specifically, the temperature in both the heating crucible and the reaction crucible is 1600℃~1700℃.

[0058] For example, the temperature in the heating crucible and the reaction crucible can be 1600°C, 1610°C, 1620°C, 1630°C, 1640°C, 1650°C, 1660°C, 1670°C, 1680°C, 1690°C or 1700°C.

[0059] Specifically, the heating crucible is a carbon crucible; the reaction crucible is an oxide crucible.

[0060] Preferably, the carbonaceous crucible includes a graphite crucible, a silicon carbide crucible, and a composite carbonaceous crucible; the oxide crucible includes an alumina crucible and a magnesium oxide crucible.

[0061] It should be noted that in this invention, the induction heating device used to heat the heating crucible and the reaction crucible is based on electromagnetic induction. By converting the power frequency alternating current into a medium frequency current, an alternating magnetic field is generated in the induction coil, which causes eddy currents to be generated inside the crucible, thereby achieving rapid heating.

[0062] When using a traditional single crucible, the graphite crucible reacts with the niobium-containing titanium slag at high temperatures to generate high-melting-point niobium carbide and titanium carbide, reducing the niobium and titanium content in the niobium-titanium ferroalloy and increasing the slag viscosity, making slag-metal separation difficult. Furthermore, the oxide crucible, in prolonged contact with the niobium-containing titanium slag at high temperatures, is easily corroded and cracked, severely impacting the reaction success rate and crucible lifespan. This method employs a separate crucible design: a carbonaceous crucible (such as a graphite crucible) is used for melting the niobium-containing titanium slag, while an oxide crucible (such as an alumina or magnesium oxide crucible) is used for aluminothermic reduction, thus ensuring the crucible's lifespan. The two types of crucibles cannot be interchanged.

[0063] Carbonaceous crucibles, such as graphite crucibles, are the most commonly used crucibles in medium-frequency induction furnaces because graphite in graphite crucibles is conductive and inexpensive. However, during the aluminothermic reduction stage, carbon (in carbonaceous crucibles) reacts with niobium oxide and titanium oxide to form niobium carbide or titanium carbide. These two substances cannot be collected by the alloy, resulting in low niobium and titanium content in the niobium-titanium ferroalloy. Furthermore, niobium carbide and titanium carbide have high melting points and exist in solid form in the slag, significantly increasing the viscosity of the slag and leading to slag-metal separation and smelting failure.

[0064] Oxide crucibles can prevent the formation of niobium carbide or titanium carbide during aluminothermic reduction, but they are susceptible to corrosion by niobium-containing titanium slag, so the two types of crucibles cannot be interchanged.

[0065] Preferably, the niobium-containing titanium slag contains 3%~8% Nb2O5 and 5%~12% TiO2.

[0066] Preferably, the chemical composition of the obtained niobium-titanium-iron alloy, by mass percentage, is: Nb≥13.0%, Ti≥17.0%, Si:6.0~7.5%, Al:1.2~2.75%, P≤0.039%, with the balance being Fe.

[0067] To more clearly describe the present invention, the following embodiments and comparative examples are provided for further illustration.

[0068] Example 1 A method for preparing a niobium-titanium-iron alloy includes the following steps: S1: Weigh 7 kg of niobium-containing titanium slag, with a binary basicity (mCaO / mSiO2) of 1.0, and crush the niobium-containing titanium slag into D... 50 Slag particles with a diameter of 30 mm were added to a heating crucible, with the feeding height reaching 60% of the crucible's height. The niobium-titanium slag contained 4.38% Nb₂O₅ and 8.56% TiO₂. S2: Add 0.8 kg of iron block to the reaction crucible; S3: Heat the heating crucible and reaction crucible to 1600℃, melt the niobium-titanium slag and iron block separately, and then add an aluminum-oxygen ratio of 1:2.7 and a density of 4.5 g / cm³ to the reaction crucible. 3 Aluminum-iron alloy; S4: The molten niobium-containing titanium slag is added to the reaction crucible for aluminothermic reduction to obtain niobium-titanium-iron alloy liquid. The liquid is then held at 1600℃ for 100 s and cast to obtain niobium-titanium-iron alloy.

[0069] The composition of the obtained niobium-titanium-iron alloy is shown in Table 1.

[0070] This embodiment uses aluminothermic reduction production equipment to prepare niobium-titanium-iron alloy.

[0071] The aluminothermic reduction production apparatus includes a heating crucible and a reaction crucible, which are non-coaxial, with their axes parallel to each other and the heating crucible positioned higher than the reaction crucible. Both the heating and reaction crucibles are connected to a tilting device. Each crucible is located within an induction coil of an induction heating device. The aluminothermic reduction production apparatus also includes an ingot mold for receiving the niobium-titanium-iron alloy molten metal obtained after aluminothermic reduction.

[0072] Example 2 The preparation process of Example 2 is largely the same as that of Example 1, except that the binary basicity of the niobium-titanium slag in Example 2 is 1.1, and the composition of the obtained niobium-titanium-iron alloy is shown in Table 1.

[0073] Example 3 The preparation process of Example 3 is largely the same as that of Example 1, except that the binary basicity of the niobium-titanium slag in Example 3 is 0.9, and the composition of the obtained niobium-titanium-iron alloy is shown in Table 1.

[0074] Example 4 The preparation process of Example 4 is largely the same as that of Example 1, except that the aluminum-oxygen ratio in Example 4 is 1:2.4, and the composition of the obtained niobium-titanium-iron alloy is shown in Table 1.

[0075] Example 5 The preparation process of Example 5 is largely the same as that of Example 1, except that the aluminothermic reduction production apparatus used in Example 5 includes a heating crucible and a reaction crucible, which are coaxially arranged, with the heating crucible higher than the reaction crucible. The heating crucible is connected to a moving device, and the reaction crucible is connected to a tilting device. The heating crucible and the reaction crucible are respectively located within the induction coil of an induction heating device. The aluminothermic reduction production apparatus also includes an ingot mold for receiving the niobium-titanium-iron alloy liquid obtained after aluminothermic reduction.

[0076] When the heating crucible and the reaction crucible are coaxially arranged, the cross-section of the heating crucible through the axis is U-shaped, and a through hole is opened at the bottom of the heating crucible. The diameter of the through hole is 70% of the diameter of the heating crucible. A circular control plate is placed inside the heating crucible. The control plate is placed on the through hole, and the diameter of the control plate is 110% of the diameter of the through hole. The control plate is made of iron-carbon alloy, and the carbon content in the iron-carbon alloy is 0.6 wt%. The composition of the obtained niobium-titanium-iron alloy is shown in Table 1.

[0077] Example 6 The preparation process of Example 6 is largely the same as that of Example 5, except that the binary basicity of the niobium-titanium slag in Example 6 is 1.1, and the composition of the obtained niobium-titanium-iron alloy is shown in Table 1.

[0078] Example 7 The preparation process of Example 7 is largely the same as that of Example 5, except that the binary basicity of the niobium-titanium slag in Example 7 is 0.9, and the composition of the obtained niobium-titanium-iron alloy is shown in Table 1.

[0079] Comparative Example 1 The preparation process of Comparative Example 1 is largely the same as that of Example 1, except that aluminum metal with an aluminum-oxygen ratio of 1:2.7 is added to the reaction crucible in Comparative Example 1.

[0080] Comparative Example 2 The preparation process of Comparative Example 2 is largely the same as that of Example 1, except that the aluminum-oxygen ratio in Comparative Example 2 is 1:3.

[0081] Comparative Example 3 The preparation process of Comparative Example 3 is largely the same as that of Example 1, except that a crucible is used in Comparative Example 3 to prepare the niobium-titanium-iron alloy, and the crucible is made of graphite.

[0082] After the reaction was completed and the mixture was poured out, the slag and iron were not separated, and no niobium-titanium-iron alloy was obtained, making it impossible to perform composition analysis. Niobium-titanium carbide was formed on the graphite crucible wall.

[0083] Comparative Example 4 The preparation process of Comparative Example 4 was largely the same as that of Example 1, except that a single crucible, made of alumina, was used to prepare the niobium-titanium-iron alloy in Comparative Example 4. The crucible shattered during heating, resulting in experimental failure.

[0084] Comparative Example 5 The preparation process of Comparative Example 5 is largely the same as that of Example 1, except that a crucible is used in Comparative Example 5 to prepare the niobium-titanium-iron alloy. The crucible is made of alumina and aluminum is added in the crucible with an aluminum-oxygen ratio of 1:2.7.

[0085] The alumina crucible was severely corroded by niobium-titanium slag during heating and reaction, and could only produce one furnace normally, resulting in a short service life.

[0086] Comparative Example 6 The preparation process of Comparative Example 6 is largely the same as that of Example 1, except that the heating crucible and the reaction crucible are switched in Comparative Example 6, and niobium-titanium slag is added to the reaction crucible; the heating crucible is used to melt the iron block and aluminum-iron alloy and to perform aluminothermic reduction.

[0087] The reaction crucible (alumina crucible) was corroded and developed holes; the heating crucible (graphite crucible) reacted with niobium-containing titanium slag during the aluminothermic reduction stage to produce niobium carbide and titanium carbide, which could not be collected and used to prepare niobium-titanium-iron alloy.

[0088] Performance testing The components of the above-described embodiments and comparative examples were tested, and the results are shown in Table 1.

[0089] Table 1. Component Analysis Results (Unit: %)

[0090] As can be seen from Examples 1-7 and Comparative Examples 1-6 and Table 1, this method melts niobium-titanium slag and iron blocks in steps, adds aluminum-iron alloy to the reaction crucible, and then adds molten slag liquid for reduction reaction. This avoids the violent splashing caused by aluminum particles floating on the slag surface in the traditional method, making the reaction process more stable, significantly reducing safety risks, and reducing material loss caused by high-temperature splashing. This increases the niobium and titanium content in the obtained niobium-titanium-iron alloy, making the niobium content in the niobium-titanium-iron alloy above 13.0% and the titanium content above 17.0%.

[0091] This method employs a separate crucible design: a carbon crucible (such as a graphite crucible) is used for melting niobium-containing titanium slag, while an oxide crucible (such as an alumina or magnesium oxide crucible) is used for aluminothermic reduction. This effectively avoids the formation of niobium carbide and titanium carbide, as well as their corrosion, thus ensuring the service life of the crucible.

[0092] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. An apparatus for producing niobium-titanium-iron alloy, characterized in that, It includes a heating crucible and a reaction crucible, wherein the heating crucible is higher than the reaction crucible; the heating crucible is a carbonaceous crucible; and the reaction crucible is an oxide crucible. The heating crucible is used to melt niobium-containing titanium slag; the reaction crucible is used to melt iron blocks and aluminum-iron alloys and to perform aluminothermic reduction.

2. The equipment for producing niobium-titanium-iron alloy according to claim 1, characterized in that, The heating crucible and the reaction crucible are not coaxial, and their axes are parallel to each other.

3. The equipment for producing niobium-titanium-iron alloy according to claim 2, characterized in that, Includes a tilting device for rotating the heating crucible and the reaction crucible.

4. The equipment for producing niobium-titanium-iron alloy according to claim 1, characterized in that, The heating crucible and the reaction crucible are arranged coaxially.

5. The equipment for producing niobium-titanium-iron alloy according to claim 4, characterized in that, The heating crucible has a U-shaped cross-section and a through hole at the bottom. A circular control plate is placed inside the heating crucible, and the control plate is located on the through hole.

6. The equipment for producing niobium-titanium-iron alloy according to claim 5, characterized in that, The diameter of the through hole is 50% to 90% of the diameter of the heating crucible.

7. The equipment for producing niobium-titanium-iron alloy according to claim 5, characterized in that, The diameter of the control piece is 110% to 120% of the diameter of the through hole.

8. The equipment for producing niobium-titanium-iron alloy according to claim 5, characterized in that, The control plate is made of an iron-carbon alloy, and the carbon content in the iron-carbon alloy is 0.01 wt% to 1 wt%.

9. The equipment for producing niobium-titanium-iron alloy according to claim 4, characterized in that, It includes a tilting device and a vertically sliding moving device. The heating crucible is connected to the moving device, which is used to adjust the distance between the heating crucible and the reaction crucible. The tilting device is connected to the reaction crucible and is used to tilt the niobium-titanium-iron alloy liquid in the reaction crucible into the ingot mold.

10. A method for the aluminothermic reduction of niobium-titanium-iron alloy, characterized in that, The niobium-titanium-iron alloy is prepared using the equipment described in any one of claims 1-9; niobium-containing titanium slag is added to a heating crucible; an iron block is added to a reaction crucible; the heating crucible and the reaction crucible are heated to melt the niobium-containing titanium slag and the iron block respectively; an aluminum-iron alloy is then added to the reaction crucible; the melted niobium-containing titanium slag is added to the reaction crucible for aluminothermic reduction to obtain a niobium-titanium-iron alloy liquid; and the niobium-titanium-iron alloy is obtained after casting.

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