Method and device for preparing titanium alloy based on aluminothermic reduction method

Abstract

The invention provides a method and device for preparing titanium alloy based on an aluminothermic reduction method. The method comprises the steps that multiple kinds of raw material powder used for forming the titanium alloy are mixed with aluminum powder according to a preset proportion, and multiple mixtures are obtained; stacking the plurality of mixtures in layers according to the thermit reaction rates of the plurality of mixtures, adding a slag former into the mixture in the middle layer, and applying a diluent on the surface of the mixture in the top layer to form a thermit reactor; and sequentially igniting the mixture of each layer from the top layer of the thermit reactor to carry out thermit reaction until the mixture is cooled to obtain the titanium alloy. According to the invention, an aluminothermic reaction gradient thermal field is formed through layered design, and a relatively violent reaction is designed at the bottom of the aluminothermic reactor, so that grade deviation caused by splashing can be prevented, slag flowing can be effectively promoted, and reduced metal liquid is forced to form up-down circulation and be fully fused so as to ensure the component uniformity of titanium alloy; and the method has the advantages of low raw material purity requirement, simple process flow and rapid reaction.

Description

Technical Field

[0001] This invention relates to the field of titanium alloy preparation, and in particular to a method and apparatus for preparing titanium alloys based on the aluminothermic reduction method. Background Technology

[0002] Vanadium-chromium-titanium alloy (V-Cr-Ti) has important applications in many high-tech and extreme environment fields due to its unique combination of properties (such as low activation, radiation resistance, high temperature stability, and corrosion resistance).

[0003] Traditional methods for preparing vanadium-chromium-titanium alloys mainly include vacuum melting and powder metallurgy, but these methods have the following drawbacks: ① High raw material costs: They rely on high-purity metals (such as sponge vanadium and pure titanium), resulting in high production costs. ② Complex processes: They require multiple melting, refining, and subsequent processing steps, leading to high energy consumption and long cycles. ③ Poor compositional uniformity: Segregation is prone to occur during the melting process, affecting the alloy's properties. Summary of the Invention

[0004] To reduce the raw material cost, process difficulty, and energy consumption in the preparation of titanium alloys, and to improve the preparation efficiency and compositional uniformity of titanium alloys, a method for preparing titanium alloys based on the aluminothermic reduction method is proposed in the first aspect of the present invention. The method includes: mixing various raw material powders for forming titanium alloys with aluminum powder in a preset ratio to obtain various mixtures; stacking the various mixtures in layers according to the aluminothermic reaction rate of the various mixtures, adding a slagging agent to the mixture in the middle layer and applying a diluent to the surface of the mixture in the top layer to form an aluminothermic reactor; and sequentially igniting the mixtures in each layer from the top layer of the aluminothermic reactor to induce an aluminothermic reaction until cooling to obtain the titanium alloy.

[0005] In one or more embodiments, the titanium alloy includes a vanadium-chromium-titanium alloy, and the various raw material powders include: vanadium source powder mainly composed of vanadium pentoxide, chromium source powder mainly composed of chromium trioxide, and titanium source powder mainly composed of titanium dioxide.

[0006] In one or more embodiments, the mixing of the various raw material powders used to form the titanium alloy with aluminum powder in a preset ratio includes determining the mixing ratio of each raw material powder to aluminum powder according to the following formula:

[0007] Where n is the mass.

[0008] In one or more embodiments, the hierarchical structure of the aluminothermic reactor includes: The bottom layer consists of a mixture of vanadium source powder and aluminum powder; The middle layer consists of a mixture of chromium source powder, aluminum powder, and slagging agent; The top layer consists of a mixture of titanium source powder, aluminum powder, and diluent.

[0009] In one or more embodiments, the slag-forming agent comprises CaF2, and the diluent comprises CaO.

[0010] In one or more embodiments, the amount of the slag-forming agent CaF2 added is 1% to 2% of the total raw material mass.

[0011] In one or more embodiments, the amount of the diluent CaO added is 1% to 2% of the total raw material mass.

[0012] In one or more embodiments, the method for preparing titanium alloys based on the aluminothermic reduction method further includes: separating the aluminothermic reactants after they have been naturally cooled to a preset temperature into slag and gold, and immersing the separated titanium alloys in water for water quenching.

[0013] In a second aspect of the invention, an apparatus for preparing titanium alloys based on the aluminothermic reduction method is provided, comprising: a split furnace shell, which is composed of a base, a middle ring, and an upper ring; a permanent layer, which is attached to the inner walls of the base 110, the middle ring 120, and the upper ring 130; a knotting filling layer, which is disposed inside the permanent layer of the base and the middle ring; and a knotting working layer, which is disposed on the permanent layer at the bottom of the base and embedded in the inner wall of the knotting filling layer and connected to form an inner cavity.

[0014] In one or more embodiments, the apparatus for preparing titanium alloys based on the aluminothermic reduction method further includes: lifting lugs respectively disposed on the outer sides of the base, the middle ring, and the upper ring; and a jig for forming and isolating the aluminothermic reactor raw materials, the knotting filling layer, and the knotting working layer.

[0015] The beneficial effects of this invention include: by creating a gradient thermal field for the aluminothermic reaction through a layered design, and by placing the intense reaction at the bottom of the aluminothermic reactor, this invention can prevent grade deviations caused by splashing, effectively promote slag flow, and allow the molten metal reduced by the aluminothermic reaction to circulate and fully fuse, thereby ensuring the compositional uniformity of the titanium alloy. Furthermore, the aluminothermic reaction has low requirements for the purity of raw materials, a simple process, and a rapid reaction, which can reduce the raw material cost of titanium alloy preparation, reduce process difficulty and energy consumption, and improve the preparation efficiency and compositional uniformity of titanium alloys, among other beneficial effects. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other embodiments can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a flowchart illustrating the process of preparing titanium alloys based on the aluminothermic reduction method according to an embodiment of the present invention. Figure 2 This is a schematic diagram of the apparatus for preparing titanium alloys based on the aluminothermic reduction method according to an embodiment of the present invention. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to specific examples and the accompanying drawings.

[0019] like Figure 1 As shown, this application proposes a method for preparing titanium alloys based on the aluminothermic reduction method. The method includes: Step S1, mixing various raw material powders used to form the titanium alloy with aluminum powder according to a preset ratio to obtain various mixtures, wherein the various raw material powders refer to raw materials containing the main elements of the titanium alloy and must have a certain purity; Step S2, stacking the various mixtures in layers according to the aluminothermic reaction rate of the various mixtures, adding a slag-forming agent to the mixture in the middle layer and applying a diluent to the surface of the mixture in the top layer to form an aluminothermic reactor. The purpose of this step is to reduce the grade deviation caused by splashing, so that the aluminothermic reaction with the highest reaction efficiency, i.e., the most intense reaction and the most exothermic reaction, occurs at the bottom layer of the aluminothermic reactor, and the aluminothermic reaction with the next highest reaction efficiency and exothermic heat occurs in the upper layer of the aluminothermic reaction, thereby effectively avoiding splashing and using the high temperature of the upper layer aluminothermic reaction to promote the lower layer aluminothermic reaction to improve the reducibility and reduction efficiency of the aluminothermic reaction; furthermore, the purpose of adding a diluent to the surface layer of the aluminothermic reactor is to dilute the viscosity of the slag, improve the slag fluidity, and better achieve the separation of slag and alloy. The purpose of reducing the surface aluminothermic reaction efficiency is to reduce the grade deviation caused by surface splashing, while the purpose of adding a slagging agent in the intermediate layer is to enable the slagging agent to react with the products generated during the aluminothermic reaction. The slag forms a eutectic to effectively lower the melting point of the entire slag system, making the slag more fluid at the smelting temperature. This allows the metal droplets reduced in the aluminothermic reaction to settle more easily to the bottom and accumulate, thus achieving a clear slag-metal separation layer. In addition, the good fluidity of the slag also facilitates the smooth escape of the gases generated during the reaction, preventing the formation of pores in the alloy. Meanwhile, the low-melting-point slag with good fluidity will cover the surface of the molten alloy liquid, forming a liquid protective layer. This layer can isolate the air to prevent the alloy from being oxidized again at high temperatures. In addition, the better fluidity can also ensure the full fusion of the reducing metal droplets in each layer, resulting in better compositional uniformity of the generated titanium alloy. Step S3: The mixture of each layer is ignited sequentially from the top layer of the aluminothermic reactor to carry out the aluminothermic reaction until it is cooled to obtain the titanium alloy. The ignition method of the aluminothermic reactor includes using titanium powder as an igniter. The titanium powder is ignited by the burning flame, which then ignites the top layer reactants of the aluminothermic reactor. The heat generated by the aluminothermic reaction is used to ignite the reactants in the lower layers in turn. Using titanium powder as an igniter can avoid the introduction of impurities. Furthermore, igniting the aluminothermic reaction from the top layer can promote the downward flow of the reducing metal to achieve full fusion with the lower layer reducing metal, thereby improving the compositional uniformity of the titanium alloy.

[0020] In one embodiment, taking the preparation of vanadium-chromium-titanium alloy as an example, the various raw material powders include: vanadium source powder mainly composed of vanadium pentoxide, chromium source powder mainly composed of chromium trioxide, and titanium source powder mainly composed of titanium dioxide. The purity of the vanadium source, chromium source, and titanium source should be greater than or equal to 98%, the purity of the aluminum powder should be greater than or equal to 99.5%, and the particle size should be 1-3 mm.

[0021] In a further embodiment, mixing the various raw material powders used to form the titanium alloy with aluminum powder in a preset ratio includes determining the mixing ratio of each raw material powder to aluminum powder according to the following formula:

[0022] Where n is the mass.

[0023] In a further embodiment, the hierarchical structure of the aluminothermic reactor includes: a bottom layer composed of a mixture of vanadium source powder and aluminum powder; a middle layer composed of a mixture of chromium source powder, aluminum powder, and a slagging agent; and a top layer composed of a mixture of titanium source powder, aluminum powder, and a diluent, wherein the slagging agent includes CaF2, and the amount of CaF2 added is 1% to 2% of the total raw material mass; the diluent includes CaO, and the amount of CaO added is 1% to 2% of the total raw material mass.

[0024] In a further embodiment, the method of the present invention further includes: separating the aluminothermic reactants after they have been naturally cooled to a preset temperature into slag and gold, and immersing the separated titanium alloy in water for water quenching, wherein water quenching can rapidly cool the titanium alloy and reduce the formation of oxide film.

[0025] The complete process flow for preparing vanadium-chromium-titanium alloy using the method of the present invention is as follows: Vanadium pentoxide crushing: Vanadium pentoxide is crushed to a particle size ≤1-3mm; Ingredients: Calculate the theoretical amount of aluminum based on the total molar amount of vanadium pentoxide, with an excess of 1% to 3%; Mixing: Vanadium oxide (V₂O₅) and chromium oxide (C₂O₅) are mixed. r2 O3), titanium oxide (TiO2) and aluminum powder are mixed evenly in a certain proportion for 5 minutes; Additives: Bottom layer: V2O5, Al powder; Middle layer: C r2 O3 + Al powder + CaF2; Top layer: TiO2 + Al powder + diluent to level the materials in the furnace; Add diluent: CaO, the amount of which is 1% to 2% of the total raw material mass, and spread it evenly on the surface of the material; Ignition initiates the aluminothermic reaction, using a burning flame to ignite the igniter (titanium powder) and cause the furnace charge to undergo an aluminothermic reaction. After the reaction is complete, allow it to stand and cool for approximately 12 hours. Water quenching: The resulting alloy and slag are separated and the vanadium-aluminum alloy is placed in a water quenching tank for rapid cooling. The water quenching time is about 2 hours.

[0026] Example 1 Take 164 kg of crushed V2O5, add 83.5 kg of aluminum granules and mix for 5 minutes; take C r2 5.8 kg of O3 powder was mixed with 3.15 kg of aluminum granules and stirred for 3 min; 6.7 kg of TiO2 powder was mixed with 2.95 kg of aluminum granules and 1 kg of CaF2 and stirred for 2 min; V2O5 mixture and C were then added sequentially. r2 The O3 mixture and TiO2 mixture were spread evenly in the furnace and leveled. 2.65 kg of diluent (CaO) was added and spread evenly on the surface of the V2O5 mixture. 120 g of microalloying agent Ti powder (99% purity) was added and spread evenly on top of the furnace charge. The smelting furnace was then moved into the smelting reaction chamber, and the titanium powder was ignited with a flame. The self-heating reaction of the furnace charge proceeded rapidly, completing in approximately 60 seconds. After cooling for 12 hours, and naturally cooling to below 150°C, the furnace body was disassembled, and the slag and alloy cake were separated. The alloy cake was water-quenched for 2 hours. Sampling analysis revealed V 91.5%, Cr 4.01%, Ti 4.12%, Al ≤ 0.2%, Fe ≤ 0.05%, Si ≤ 0.05%, C ≤ 0.02%, and O ≤ 0.01%.

[0027] Example 2 Take 165 kg of crushed V2O5, add 83.9 kg of aluminum granules and mix for 5 minutes; take C r26 kg of O3 powder was mixed with 3.2 kg of aluminum granules and stirred for 3 min; 6.8 kg of TiO2 powder was mixed with 3.0 kg of aluminum granules and 1 kg of CaF2 and stirred for 2 min; V2O5 mixture and C were then added sequentially. r2 A mixture of O3 and TiO2 was spread evenly in the furnace and leveled. 2.65 kg of diluent (CaO) was added and spread evenly on the surface. 120 g of microalloying agent (99% purity) Ti powder was added and spread evenly on top of the furnace charge. The furnace was then moved into the smelting reaction chamber, and the titanium powder was ignited with a flame. The self-heating reaction of the furnace charge proceeded rapidly, completing in approximately 60 seconds. After cooling for 12 hours, and naturally cooling to below 150°C, the furnace body was disassembled, and the slag and alloy cake were separated. The alloy cake was water-quenched for 2 hours. Sampling analysis revealed V 91.7%, Cr 4.01%, Ti 4.15%, Al ≤ 0.2%, Fe ≤ 0.05%, Si ≤ 0.05%, C ≤ 0.02%, and O ≤ 0.01%.

[0028] Example 3 Take 165 kg of crushed V2O5, add 83.9 kg of aluminum granules and mix for 5 minutes; take C r2 6 kg of O3 powder was mixed with 3.5 kg of aluminum granules and stirred for 3 min; 6.8 kg of TiO2 powder was mixed with 3.0 kg of aluminum granules and 1 kg of CaF2 and stirred for 2 min; V2O5 mixture and C were then added sequentially. r2 A mixture of O3 and TiO2 was spread evenly in the furnace and leveled. 2.8 kg of diluent (CaO) was added and spread evenly on the surface. 120 g of microalloying agent (99% purity) Ti powder was added and spread evenly on top of the furnace charge. The furnace was then moved into the smelting reaction chamber, and the titanium powder was ignited with a flame. The self-heating reaction of the furnace charge proceeded rapidly, completing in approximately 60 seconds. After cooling for 12 hours, and naturally cooling to below 150°C, the furnace body was disassembled, and the slag and alloy cake were separated. The alloy cake was water-quenched for 2 hours. Sampling analysis revealed V 91.5%, Cr 4.02%, Ti 4.05%, Al ≤ 0.2%, Fe ≤ 0.05%, Si ≤ 0.05%, C ≤ 0.02%, and O ≤ 0.01%.

[0029] As can be seen from the above embodiments, when titanium alloys are prepared using the method of the present invention, the titanium alloy composition remains stable and the impurities are low even with slight deviations in material composition. Therefore, the method of the present invention has low process requirements, high reliability, and relatively stable product composition.

[0030] In the above embodiments, the present invention forms a gradient thermal field for the aluminothermic reaction through a layered design. The intense reaction is designed at the bottom of the aluminothermic reactor, which can prevent grade deviation caused by splashing, effectively promote slag flow, and allow the molten metal reduced by the aluminothermic reaction to form an up-and-down circulation and fully integrate, thereby ensuring the compositional uniformity of the titanium alloy. Furthermore, the aluminothermic reaction has low requirements for the purity of raw materials, a simple process, and a rapid reaction, which can achieve many beneficial effects such as reducing the raw material cost of titanium alloy preparation, reducing process difficulty and energy consumption, and improving the preparation efficiency and compositional uniformity of titanium alloy.

[0031] In a second aspect of the invention, an apparatus for preparing titanium alloys based on the aluminothermic reduction method is also provided, such as... Figure 2 As shown, its structure includes: a split furnace shell 100, which consists of a base 110, a middle ring 120, and an upper ring 130; a permanent layer 200, which is attached to the inner wall of the base 110, the middle ring 120, and the upper ring 130 to protect the furnace body from high-temperature deformation and thus extend the service life of the furnace body; a knotted filling layer 300, which is set inside the permanent layer of the base 110 and the middle ring 120, and is formed by filling with corundum slag; and a knotted working layer 400, which is set on the permanent layer at the bottom of the base 110 and embedded in the inner wall of the knotted filling layer 200 and connected to form an inner cavity, and is formed by filling with white corundum. The main function of the upper ring 130 is to prevent splashing during the aluminothermic reaction. The middle ring 120 and the base 110 are the aluminothermic reactor and reaction space. Therefore, the height of the knotting filling layer 300 is only level with or slightly beyond the top of the middle ring 120. The knotting working layer 400 is filled with white corundum, which mainly serves to insulate heat and prevent the introduction of impurities. The knotting filling layer 300 is filled with corundum slag, which mainly serves to insulate heat and realize the secondary utilization of resources (corundum slag generated by itself), which can effectively reduce production costs.

[0032] In one embodiment, the apparatus for preparing titanium alloys based on the aluminothermic reduction method of the present invention further includes: lugs 111, 121, and 131 respectively disposed on the outer side of the base, the middle ring, and the upper ring; and a jig 600 for forming and isolating the aluminothermic reactor raw materials, the knotted filling layer 300, and the knotted working layer 400, wherein the jig 600 is composed of two cylinders 510 and 520, wherein the height of cylinder 510 is higher than the height from the bottom of the base 110 to the top of the middle ring 120, and the diameter is smaller than the overall diameter of the furnace body, for adding reactant material at the center of cylinder 510 and adding corundum slag between the outer side of cylinder 510 and the inner side of the middle ring to form the knotted filling layer 300; the height of cylinder 520 is higher than the top of the base 110 but lower than the top of the middle ring 120, and the diameter is larger than the diameter of cylinder 410 but smaller than the overall diameter of the furnace body, for embedding the filling and knotting working layer 400 in the knotted filling layer 300, and its height is the same as or slightly higher than the height of the titanium alloy molten metal to be generated. During use, the fixture needs to be removed after the reactant, the knotting filling layer 300, and the knotting working layer 400 are set.

[0033] In one embodiment, the knotting working layer 400 of the present invention can also be replaced with a graphite crucible. The assembly process of the furnace body is as follows: place the graphite crucible in the middle position of the smelting furnace base 110 and place the jig 500 outside the graphite crucible; hoist the middle ring 120 and place it upright outside the graphite crucible and the jig 500, so that the middle ring 120 and the outer wall of the graphite crucible are kept at a uniform distance; fill the space between the permanent layer of the middle ring 120 and the jig 500 with corundum slag and white corundum (at this time, the filling can be carried out to form an aluminothermic reactor); finally, hoist the upper ring 130 and place it upright on top of the middle ring 120 to complete the assembly of the furnace body.

[0034] The above are exemplary embodiments disclosed in this invention. However, it should be noted that various changes and modifications can be made without departing from the scope of the embodiments of this invention as defined by the claims. The functions, steps, and / or actions of the methods according to the disclosed embodiments described herein do not need to be performed in any particular order. The embodiment numbers disclosed above are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0035] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention (including the claims) is limited to these examples. Within the framework of the invention, technical features of the above embodiments or different embodiments can be combined, and many other variations of different aspects of the invention exist, which are not provided in the details for the sake of brevity. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the invention should be included within the protection scope of the invention.

Claims

1. A method for preparing titanium alloys based on aluminothermic reduction, characterized in that, The method includes: Various raw material powders used to form titanium alloys are mixed with aluminum powder in a preset ratio to obtain various mixtures; The various mixtures are stacked in layers according to their aluminothermic reaction rates, and a slagging agent is added to the mixture in the middle layer and a diluent is applied to the surface of the mixture in the top layer to form an aluminothermic reactor. The titanium alloy is obtained by sequentially igniting the mixture of each layer from the top layer of the aluminothermic reactor to induce an aluminothermic reaction until cooling.

2. The method for preparing titanium alloys based on the aluminothermic reduction method according to claim 1, characterized in that, The titanium alloy includes a vanadium-chromium titanium alloy, and the various raw material powders include: vanadium source powder mainly composed of vanadium pentoxide, chromium source powder mainly composed of chromium trioxide, and titanium source powder mainly composed of titanium dioxide.

3. The method for preparing titanium alloys based on the aluminothermic reduction method according to claim 2, characterized in that, The step of mixing the various raw material powders used to form the titanium alloy with aluminum powder in a preset ratio includes determining the mixing ratio of each raw material powder to aluminum powder according to the following formula: Where n is the mass.

4. The method for preparing titanium alloys based on the aluminothermic reduction method according to claim 2, characterized in that, The hierarchical structure of the aluminothermic reactor includes: The bottom layer consists of a mixture of vanadium source powder and aluminum powder; The middle layer consists of a mixture of chromium source powder, aluminum powder, and slagging agent; The top layer consists of a mixture of titanium source powder, aluminum powder, and diluent.

5. The method for preparing titanium alloys based on the aluminothermic reduction method according to claim 1 or 4, characterized in that, The slag-forming agent includes CaF2, and the diluent includes CaO.

6. The method for preparing titanium alloys based on the aluminothermic reduction method according to claim 5, characterized in that, The amount of the slag-forming agent CaF2 added is 1%-2% of the total raw material mass.

7. The method for preparing titanium alloys based on the aluminothermic reduction method according to claim 5, characterized in that, The amount of CaO added as a diluent is 1% to 2% of the total raw material mass.

8. The method for preparing titanium alloys based on the aluminothermic reduction method according to claim 1, characterized in that, The method further includes: After the aluminothermic reactants are naturally cooled to a preset temperature, slag-metal separation is performed, and the separated titanium alloy is immersed in water for water quenching.

9. An apparatus for preparing titanium alloys based on the aluminothermic reduction method, characterized in that, include: The furnace shell is a split type, consisting of a base, a middle ring, and an upper ring. A permanent layer is attached to the inner walls of the base 110, the middle ring 120, and the upper ring 130. A knotted filling layer is disposed inside the permanent layer of the base and the middle ring portion; The knotting working layer is respectively disposed on the permanent layer at the bottom of the base and embedded on the inner sidewall of the knotting filling layer and connected to form an inner cavity.

10. The apparatus for preparing titanium alloys based on the aluminothermic reduction method according to claim 9, characterized in that, Also includes: The lifting lugs are respectively installed on the outer side of the base, the middle ring, and the upper ring; as well as A jig for forming and isolating the aluminothermic reactor feedstock, the knotted filler layer, and the knotted working layer.

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