Low-aluminum low-silicon titanium aluminum-based intermediate alloy as well as preparation method and application thereof

Abstract

The invention discloses a low-aluminum low-silicon titanium aluminum-based intermediate alloy and a preparation method and application thereof, and belongs to the field of alloy materials. The preparation method of the low-aluminum low-silicon titanium aluminum-based intermediate alloy comprises the following steps: S1, uniformly mixing a low-silicon titanium-containing raw material, a reducing agent, a fluxing agent and an additive to obtain a mixed material; and S2, the mixed material is put into an electro-aluminothermic reaction container, heat preservation is conducted for 60-120 min at the temperature of 1500-1650 DEG C, and the low-aluminum low-silicon titanium-aluminum-based intermediate alloy with the Al content being 8-15% and the Si content being smaller than 0.5% is obtained. The method provided by the invention can effectively solve the problem that the content of silicon and aluminum in the existing titanium-aluminum-based intermediate alloy is too high. The production process for preparing the low-aluminum low-silicon titanium aluminum-based intermediate alloy is simple, meanwhile, a novel low-cost short-process titanium alloy production process is provided, the titanium alloy production process flow is greatly shortened, the titanium alloy production cost is reduced, and the high application and popularization value is achieved.

Description

Technical Field

[0001] The invention belongs to the field of alloy materials, and in particular relates to a low-aluminum and low-silicon titanium-aluminum-based master alloy and a preparation method and application thereof. Background Art

[0002] At present, South Korea, Japan and other countries have conducted a lot of research on low-cost titanium alloys. The low-cost titanium alloys prepared have excellent performance, good processability, good strength, plasticity, fracture toughness and fatigue resistance after heat treatment, and can be used in the fields of automobiles, biomedicine, and health care. However, the preparation of these low-cost titanium alloys still uses traditional processes, using sponge titanium as the main raw material, and using cheap elements to replace expensive elements such as V and Cr to reduce costs. The production process of low-cost titanium alloys is long, and the cost reduction space is limited.

[0003] At present, the method of extracting metals is still dominated by the preparation of sponges by the Kro11 method. The technology, process and equipment level of this method are quite mature, and the space for cost reduction and efficiency improvement by using this method is extremely limited; and the production process of titanium alloys by this method is long, energy-intensive and costly. Boeing once calculated that the cost of sponge titanium accounts for 80% of titanium ingots and 40% of the total cost of titanium alloy products. Therefore, in order to significantly reduce production costs, it is necessary to bypass the long process and high energy consumption of the Kro11 method, and rely on emerging technologies to directly extract metals from titanium dioxide. Low-cost and short processes for titanium alloys are an inevitable trend. In recent years, emerging methods for extracting metallic titanium include molten salt electrolysis (EDO), self-propagating high-temperature synthesis (SHS), and electric aluminum thermal method. The new method has a short process, low energy consumption, and a production cost that is 30% to 40% lower than the Kro11 method. However, these methods have problems such as the difficulty in separating slag and gold, and the high aluminum-silicon content of the prepared titanium-aluminum-based intermediate alloy.

[0004] The existing short-process preparation of titanium-aluminum-based master alloys in my country has the problem of high silicon and aluminum content. The silicon content is higher than 3%, and the aluminum content is higher than 26%. Excessive silicon and aluminum content will have adverse effects on the subsequent preparation of titanium alloys:

[0005] (1) Performance. Si easily reacts with Ti to form Ti5Si3 phase at the grain boundary. It has a high melting point and meets the energy fluctuation requirements. It can serve as a heterogeneous nucleation core and increase the nucleation rate. Therefore, as the Si content increases, the Ti5Si3 phase increases at the grain boundary, hindering the growth of grains. When the Si content exceeds 2%, as the Si content increases, the Ti5Si3 phase grows rapidly to form Ti5Si3 particles. Ti5Si3 particles appear in a hexagonal structure in the titanium-aluminum-based alloy microstructure. Its size is larger than other structures, and its hardness is high. It is easy to fall off at the grain boundary and initiate crack sources, so the brittleness of the alloy increases. Aluminum can form a dense oxide film on the surface of the alloy, effectively preventing the corrosion and oxidation of the alloy. It can also cause the distortion of the alloy crystal lattice by forming a solid solution, thereby improving the hardness and strength of the material, improving its processability and corrosion resistance, and making it still have good mechanical properties in harsh environments such as high temperature and high pressure. At the same time, aluminum can also enhance the thermal stability of the alloy, making it less likely to deform and break under high temperature and high stress. However, the addition of aluminum has a certain effect on the plasticity of titanium alloy. An appropriate amount of aluminum can increase the strength of the alloy, but it will also reduce the deformation resistance.

[0006] (2) Cost. The aluminum content of various grades of titanium alloys in the national standard GB / T 3620.1-2016 "Titanium and Titanium Alloy Grades and Chemical Composition" is less than 9%, and the silicon content of most titanium alloys does not exceed 0.1%. A few titanium alloys have a silicon content of more than 0.1%, but not more than 0.4%. Therefore, the higher the aluminum and silicon content in the titanium-aluminum-based master alloy, the more sponge titanium or other additives need to be added for tempering, thereby increasing product costs.

[0007] CN102605183A discloses a method for preparing a low-silicon and low-carbon ferroniobium alloy. The method for preparing a low-silicon and low-carbon ferroniobium alloy of the invention is based on the existing aluminothermic reduction method outside the furnace. According to the characteristics of the aluminothermic reduction method outside the furnace, the carbon and silicon content in the product is stabilized and reduced by preheating the raw materials, accurately proportioning, and fully mixing the materials, so as to obtain a product with C≤0.03% and Si≤0.5%. This method reduces silicon by accurately proportioning during the reduction process, and finally achieves Si≤0.5% in the product, which has high requirements on the quality of the raw materials.

[0008] Huang Dong (Huang Dong. Research on the process of preparing titanium-aluminum-based multi-element alloy by aluminothermic reduction of titanium slag under ultra-gravity conditions [D]. Xihua University, 2019. DOI: 10.27411 / d.cnki.gscgc.2019.000341.) used Panzhihua acid-soluble titanium slag (the content of titanium dioxide is about 72%) as raw material, and prepared titanium-aluminum-based master alloy by aluminothermic reduction method under ultra-gravity conditions. The Ti content of the titanium-aluminum-based master alloy was 55.51%, the Al content was 31.23%, and the Si content was 4.03%. The titanium-aluminum-based master alloy prepared by this method has high aluminum and silicon contents, which will increase the cost of subsequent preparation of titanium alloys. In addition, the method involves the modification of ultra-gravity equipment, and the equipment cost is relatively high. Summary of the invention

[0009] The technical problem to be solved by the present invention is that the silicon and aluminum contents of the existing titanium-aluminum-based master alloy are too high.

[0010] The technical solution adopted by the present invention to solve its technical problem is:

[0011] In a first aspect, the present invention provides a method for preparing a low-aluminum, low-silicon titanium-aluminum based master alloy, comprising the following steps:

[0012] S1: mixing low-silicon titanium-containing raw materials, reducing agents, fluxing agents and additives to obtain a mixed material;

[0013] S2: putting the mixed material into an electric aluminothermic reaction vessel, keeping the temperature at 1500-1650°C for 60-120 minutes, and obtaining a low-aluminum, low-silicon titanium-aluminum based intermediate alloy with Al 8-15% and Si <0.5%.

[0014] In the above preparation method, in step S1, the particle size of the low-silicon titanium-containing raw material, the reducing agent, the flux and the additive is +500 mesh to -100 mesh.

[0015] In the above preparation method, in step S1, the low-silicon titanium-containing raw material refers to a raw material with TiO2≥45% and SiO2≤0.7%, or a raw material with TiO2≥45% and SiO2≤0.7% after being treated with an alkali leaching and silicon removal process.

[0016] Furthermore, the above-mentioned low-silicon titanium-containing raw materials include but are not limited to high-titanium slag, acid-soluble titanium slag, titanium concentrate, titanium ash powder, titanium yellow powder and titanium dioxide.

[0017] Furthermore, the above alkaline leaching desiliconization process is: drying the raw material to be treated and mixing it with sodium hydroxide solution at a rate of 4 to 10 mL·g -1 The mixture is added into the reaction vessel at a liquid-to-solid ratio, stirred at a rate of 400-500 r / min and kept warm at 50-95°C for 1.5-3.0 h, then filtered, washed and dried.

[0018] Furthermore, in the above alkaline leaching desiliconization process, the raw material is dried at 105°C for 2 hours; the concentration of the sodium hydroxide solution is 0.5 to 3.0 mol·L -1 ; Filter and wash until the filtrate pH is 7, and dry at 105℃ for 2h.

[0019] In the above preparation method, in step S1, the reducing agent includes but is not limited to at least one of aluminum, calcium and binary composite metals thereof.

[0020] In the above preparation method, in step S1, the flux includes but is not limited to at least one of calcium fluoride, calcium oxide, fluorite, limestone, dolomite, and quicklime.

[0021] In the above preparation method, in step S1, the additive includes but is not limited to at least one of iron oxide scale, iron filings, scrap steel and iron ore powder.

[0022] In the above preparation method, in step S1, the mass ratio of CaO / 2Al2O3 in the mixed material is 0.4-0.7, and CaF2 / (CaF2+Al2O3+CaO) is 0-40%.

[0023] Furthermore, in the above-mentioned mixed material, based on 100g of TiO2 effective ingredient, the mass range ratio of each effective ingredient is TiO2:Al:CaO:CaF2:Fe=100:45~64:68~129:0~146:0~8.

[0024] In a second aspect, the present invention provides a low-aluminum, low-silicon titanium-aluminum-based intermediate alloy prepared by the above preparation method.

[0025] The chemical composition of the above-mentioned low-aluminum and low-silicon titanium-aluminum-based master alloy is as follows by mass percentage: Ti 70-82%, Al 8-15%, Si 0-0.5%, Fe 0-8%, Mn 0-3%, N≤0.5%, H≤0.3%, O≤0.6%.

[0026] In a third aspect, the present invention provides the use of the low-aluminum, low-silicon titanium-aluminum-based intermediate alloy in the production of titanium alloys.

[0027] The application of the above-mentioned low-aluminum, low-silicon titanium-aluminum-based master alloy in the production of titanium alloy is: according to actual product requirements, the low-aluminum, low-silicon titanium-aluminum-based master alloy is refined and modulated to obtain a titanium alloy with a target composition.

[0028] The beneficial effects of the present invention are as follows: the present invention prepares a titanium-aluminum-based intermediate alloy by mixing a low-silicon titanium-containing raw material with a reducing agent, a flux, and an additive through a thermal reduction reaction. The titanium-aluminum-based intermediate alloy prepared by the method of the present invention has the characteristics of low silicon content (0-0.5%) and low aluminum content (8-15%).

[0029] The low-aluminum and low-silicon titanium-aluminum-based master alloy of the present invention is suitable for producing titanium alloys and has the following advantages:

[0030] (1) Performance:

[0031] Firstly, the titanium-aluminum-based intermediate alloy prepared by the present invention has a low silicon content, which can reduce the situation where the Ti5Si3 phase increases at the grain boundary and hinders the grain growth, and further avoids the formation of Ti5Si3 particles, which leads to the problem of increased alloy brittleness.

[0032] Secondly, the titanium-aluminum-based intermediate alloy prepared by the present invention has a low aluminum content. A proper amount of aluminum element can enhance the strength of the alloy without causing the problem of reduced deformation resistance of the alloy due to excessive aluminum content.

[0033] (2) Cost:

[0034] Firstly, the aluminum and silicon contents in the titanium-aluminum-based intermediate alloy prepared by the present invention are relatively low. When the intermediate alloy is used to produce titanium alloy, there is no need to add more sponge titanium or other additives for tempering, which can effectively reduce the production cost.

[0035] Secondly, the traditional titanium alloy production process from titanium raw material titanium slag (acid soluble titanium slag, high titanium slag) to titanium alloy production process (such as Figure 1 As shown in the figure, it has to go through a series of production links such as acid leaching, impurity removal, chlorination, refining, reduction, distillation, and smelting, which has a long process, high energy consumption, and high environmental protection cost. The process route for preparing low-cost titanium alloy using the titanium-aluminum-based master alloy prepared by this method (as shown in the figure) Figure 2 As shown in the figure, it is only necessary to refine and temper the titanium-aluminum-based intermediate alloy according to the actual product requirements to obtain the titanium alloy of the target composition. The production process of the titanium alloy has the characteristics of metallurgical-material integrated design, short process, low energy consumption, and clean smelting to prepare low-cost titanium alloy. The production process of the present invention for preparing low-aluminum and low-silicon titanium-aluminum-based intermediate alloy is simple, and at the same time, a new low-cost short-process production process for titanium alloy is provided, which greatly shortens the process flow of titanium alloy production, reduces the production cost of titanium alloy, and has a high value of promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 The production process of traditional titanium alloy;

[0037] Figure 2 Process flow for preparing low-cost titanium alloy for low-aluminum and low-silicon titanium-aluminum based master alloy;

[0038] Figure 3 The production process of low-aluminum and low-silicon titanium-aluminum based master alloy;

[0039] Figure 4This is a product picture of a low-aluminum, low-silicon titanium-aluminum based master alloy obtained in Example 1;

[0040] Figure 5 The microstructure of the low-aluminum and low-silicon titanium-aluminum based master alloy prepared in Example 1;

[0041] Figure 6 The microstructure of the low-aluminum, low-silicon titanium-aluminum based master alloy obtained in Example 1;

[0042] Figure 7 This is the product diagram of the completion of the aluminothermic reduction reaction in Comparative Example 1. DETAILED DESCRIPTION

[0043] The technical solution of the present invention can be specifically implemented in the following manner.

[0044] 1. Low aluminum and low silicon titanium aluminum based master alloy, the chemical composition of which is shown in Table 1.

[0045] Table 1 Chemical composition of low aluminum and low silicon titanium aluminum based master alloy / wt.%

[0046]

[0047] 2. The preparation method of the above-mentioned low-aluminum and low-silicon titanium-aluminum based master alloy, the production process flow chart is as follows Figure 3 As shown, the specific steps are as follows:

[0048] (1) Preparation of raw materials.

[0049] Low-silicon titanium-containing raw materials: refers to raw materials with TiO2 ≥ 45%, SiO2 ≤ 0.7%, or raw materials with TiO2 ≥ 45%, SiO2 ≤ 0.7% after alkaline leaching and silicon removal process; including but not limited to high-titanium slag, acid-soluble titanium slag, titanium concentrate, titanium ash powder, titanium yellow powder and titanium dioxide.

[0050] Preferably, the specific treatment method of the above-mentioned alkali leaching desiliconization process is:

[0051] 1) Drying: Dry the raw material to be treated in an oven at 105°C for 2 hours;

[0052] 2) Alkali leaching: 0.5-3.0 mol·L -1 Sodium hydroxide solution, according to the solution and the dried raw material is 4 ~ 10mL g -1 The mixture is added into a reaction vessel at a liquid-to-solid ratio of 400-500 r / min; the mixture is kept warm at 50-95°C for 1.5-3.0 h;

[0053] 3) Filtration and drying: Filtration and washing until the pH value of the filtrate is 7, the product is placed in a drying oven at 105° C. and dried for 2 hours to obtain a low-silicon titanium-containing raw material with a silicon dioxide content of ≤0.7% and a titanium dioxide content of ≥45%.

[0054] Reducing agent: includes but is not limited to at least one of aluminum, calcium and binary composite metals thereof.

[0055] Flux: including but not limited to at least one of calcium fluoride, calcium oxide, fluorite, limestone, dolomite and quicklime.

[0056] Additives: including but not limited to at least one of iron oxide scale, iron filings, scrap steel and iron ore powder.

[0057] Preferably, the particle size of the low-silicon titanium-containing raw material, reducing agent, flux and additive is +500 mesh to -100 mesh.

[0058] (2)Process flow

[0059] 1) Ingredients: The following are the reactions that may occur during the preparation of low-aluminum and low-silicon titanium-aluminum based master alloys by aluminothermic reduction reaction.

[0060] 1.5TiO2+2Al=1.5Ti+Al2O3

[0061] 3FeO+2Al=3Fe+Al2O3

[0062] 3SiO2+4Al=3Si+2Al2O3

[0063] 3MnO+2Al=3Mn+Al2O3

[0064] Cr2O3+2Al=Cr+Al2O3

[0065] Fe2O3+2Al=Fe+Al2O3

[0066] Through the above reaction, according to the CaO / 2Al2O3 mass ratio of 0.4-0.7, CaF2 / (CaF2+Al2O3+CaO) of 0-40%, the chemical composition of the target titanium-aluminum-based intermediate alloy is calculated by mass percentage as Al 8-15%, Fe 0-8%, Si 0-0.5%, and Ti as the remainder, and then weighed; the ingredient range of each raw material is as follows: based on 100g of TiO2 effective ingredient, the mass range ratio of each effective ingredient is TiO2:Al:CaO:CaF2:Fe=100:45-64:68-129:0-146:0-8.

[0067] 2) Mixing: Mix the weighed raw materials evenly.

[0068] 3) Aluminothermic reduction: The uniformly mixed raw materials are placed in an electric aluminothermic reaction vessel and kept at 1500-1650°C for 60-120 minutes to obtain a low-aluminum, low-silicon titanium-aluminum based intermediate alloy with an Al content of 8-15% and a Si content of less than 0.5%.

[0069] 3. Application of the above-mentioned low-aluminum, low-silicon titanium-aluminum-based master alloy in the production of titanium alloys. The low-aluminum, low-silicon titanium-aluminum-based master alloy is used to prepare low-cost titanium alloys. The process flow chart is as follows: Figure 2 shown.

[0070] Preferably, the specific method of the above application is: according to actual product requirements, the low-aluminum and low-silicon titanium-aluminum based intermediate alloy is refined and modulated to obtain a titanium alloy with a target composition.

[0071] The technical solution and effects of the present invention are further illustrated below through practical examples.

[0072] Example 1

[0073] 1. Raw materials: high titanium slag after alkali leaching and silicon removal treatment is used as low silicon titanium raw material, calcium oxide (analytical grade) and calcium fluoride (analytical grade) are used as flux, aluminum powder (Al content ≥ 99.5%) is used as reducing agent, and iron oxide is used as additive; wherein, the chemical composition of high titanium slag and iron oxide is shown in Table 2, and the particle size of all raw materials is +500 mesh to -100 mesh.

[0074] Table 2 Chemical composition of each raw material / wt.%

[0075]

[0076] The specific method of alkali leaching to remove silicon from high titanium slag is: drying in an oven at 105℃ for 2h; -1 The sodium hydroxide solution is 4 mL g -1 , added into the reaction vessel; stirred at 500r / min and kept warm at 90℃ for 3.0h; filtered and washed until the filtrate pH = 7, the high-titanium slag after silicon removal was placed in a drying oven at 105℃ for 2h to obtain the high-titanium slag after alkali leaching and silicon removal treatment, the main chemical components of which are shown in Table 3.

[0077] Table 3 Main chemical composition of high titanium slag after alkali leaching and silicon removal / wt.%

[0078]

[0079] 2. Preparation of low aluminum and low silicon titanium aluminum based master alloy by aluminothermic reduction:

[0080] (1) Ingredients: The target titanium-aluminum-based master alloy is weighed according to a formula in which the chemical composition of the alloy is calculated as follows: Al 10%, Fe 8%, and the remainder is Ti, with the ratio of the effective ingredients being: TiO2:Al:CaO:CaF2:Fe=100.00:56.72:91.30:77.7:4.34.

[0081] (2) Mixing: Mix the weighed raw materials evenly.

[0082] (3) Aluminothermic reduction: The uniformly mixed raw materials were placed in an electric aluminothermic reaction vessel and kept at 1550°C for 90 min to obtain a low-aluminum, low-silicon titanium-aluminum-based intermediate alloy with an Al content of 9.60% and a Si content of 0.42%. The specific main components of the alloy are shown in Table 4.

[0083] Table 4 Main components of low aluminum and low silicon titanium aluminum based master alloy of Example 1 / wt.%

[0084]

[0085] The product of the low aluminum and low silicon titanium aluminum based master alloy obtained in Example 1 is shown in FIG. Figure 4 As shown in the figure, the alloy and slag are easy to separate; the microstructure of the low aluminum and low silicon titanium aluminum based master alloy is as shown in Figure 5 As shown in the SEM microstructure Figure 6 As shown by Figures 5-6 It can be seen that the low-aluminum and low-silicon titanium-aluminum based master alloy has few inclusions.

[0086] Example 2

[0087] 1. Raw materials: Acid-soluble titanium slag treated with alkali leaching for silicon removal is used as the low-silicon titanium-containing raw material, calcium oxide (analytical grade) and calcium fluoride (analytical grade) are used as fluxes, aluminum powder (Al content ≥ 99.5%) is used as a reducing agent, and iron oxide is used as an additive; wherein the main chemical compositions of the acid-soluble titanium slag and iron oxide are shown in Table 5, and the particle size of all raw materials is +500 mesh to -100 mesh.

[0088] Table 5 Main chemical composition of each raw material / wt.%

[0089]

[0090] The specific method of removing silicon from acid-soluble titanium slag by alkali leaching is as follows: drying in an oven at 105°C for 2 hours; -1 The sodium hydroxide solution is prepared according to the liquid-solid ratio of the solution to the acid-soluble titanium slag of 10 mL g -1, added into the reaction vessel; stirred at 500r / min and kept warm at 90℃ for 3.0h; filtered and washed until the filtrate pH = 7, the acid-soluble titanium slag after silicon removal was placed in a drying oven at 105℃ for 2h to obtain the acid-soluble titanium slag after alkali leaching and silicon removal, and its main chemical components are shown in Table 6.

[0091] Table 6 Main chemical composition of acid-soluble titanium slag after alkali leaching and silicon removal / wt.%

[0092]

[0093] 2. Preparation of low aluminum and low silicon titanium aluminum based master alloy by aluminothermic reduction:

[0094] (1) Ingredients: The formula was calculated based on CaO / 2Al2O3 being 0.5, CaF2 / (CaF2+Al2O3+CaO) being 30%, Al being 15 wt.%, and Fe being 8 wt.% in the target titanium-aluminum-based master alloy, and weighed; the mass ratio of each effective component was: TiO2:Al:CaO:CaF2:Fe=100.00:63.51:93.67:81.79:0.69.

[0095] (2) Mixing: Mix the weighed raw materials evenly.

[0096] (3) Aluminothermic reduction: The uniformly mixed raw materials were placed in an electric aluminothermic reaction vessel and kept at 1550°C for 90 min to obtain a low-aluminum, low-silicon titanium-aluminum-based intermediate alloy with an Al content of 14.91% and a Si content of 0.50%. The specific alloy composition is shown in Table 7.

[0097] Table 7 Example 2 Low aluminum, low silicon titanium aluminum based master alloy composition / wt.%

[0098]

[0099] Example 3

[0100] 1. Raw materials: titanium dioxide is used as a low-silicon titanium-containing raw material (since there is no SiO2 in titanium dioxide, there is no need to perform alkaline leaching to remove silicon), quicklime and fluorite are used as fluxes, aluminum powder (Al content ≥ 99.5%) is used as a reducing agent, and iron oxide is used as an additive; the chemical composition of titanium dioxide and iron oxide is shown in Table 8, and the particle size of all raw materials is +500 mesh to -100 mesh.

[0101] Table 8 Chemical composition of each raw material / wt.%

[0102]

[0103] 2. Preparation of low aluminum and low silicon titanium aluminum based master alloy by aluminothermic reduction:

[0104] (1) Ingredients: The target titanium-aluminum-based master alloy is weighed according to a formula in which the chemical composition of the alloy is calculated as Al 12%, Fe 7%, and Ti as the remainder, with CaO / 2Al2O3 being 0.5 and CaF2 / (CaF2+Al2O3+CaO) being 20%. The weight ratio of the effective ingredients is: TiO2:Al:CaO:CaF2:Fe=100.00:57.09:87.98:43.25:4.82.

[0105] (2) Mixing: Mix the weighed raw materials evenly.

[0106] (3) Aluminothermic reduction: The uniformly mixed raw materials were placed in an electric aluminothermic reaction vessel and kept at 1600°C for 60 min to obtain a low-aluminum, low-silicon titanium-aluminum-based intermediate alloy with an Al content of 12.7% and a Si content of 0.48%. The specific alloy composition is shown in Table 9.

[0107] Table 9 Example 3 Low aluminum and low silicon titanium aluminum based master alloy composition / wt.%

[0108]

[0109] Comparative Example 1

[0110] 1. Raw materials: same as in Example 1.

[0111] 2. Preparation of low aluminum and low silicon titanium aluminum based master alloy by aluminothermic reduction:

[0112] (1) Ingredients: The target titanium-aluminum-based master alloy is formulated with a CaO / 2Al2O3 ratio of 0.3, a CaF2 / (CaF2+Al2O3+CaO) ratio of 30%, and a chemical composition of Al 10%, Fe 8%, and Ti as the remainder in terms of mass percentage, and weighed; the mass ratio of each effective component is: TiO2:Al:CaO:CaF2:Fe=100.00:56.72:54.44:61.94:4.74.

[0113] (2) Mixing: Mix the weighed raw materials evenly.

[0114] (3) Aluminothermic reduction: The mixed raw materials are placed in an electric aluminothermic reaction vessel and kept at 1550°C for 90 minutes to obtain the product as shown in the figure. Figure 7 As shown in the figure, it can be seen that after the aluminothermic reduction reaction is completed, the alloy and slag cannot be separated, so the alloy product cannot be directly produced.

Claims

1. A method for preparing a low-aluminum, low-silicon titanium-aluminum based master alloy, characterized in that: The steps include: S1: mixing low-silicon titanium-containing raw materials, reducing agents, fluxing agents and additives to obtain a mixed material; S2: putting the mixed material into an electric aluminothermic reaction vessel, keeping the temperature at 1500-1650°C for 60-120 minutes, and obtaining a low-aluminum, low-silicon titanium-aluminum based intermediate alloy with Al 8-15% and Si <0.5%.

2. The method for preparing a low-aluminum, low-silicon titanium-aluminum based master alloy according to claim 1, characterized in that: In step S1, the particle size of the low-silicon titanium-containing raw material, the reducing agent, the flux and the additive is +500 mesh to -100 mesh.

3. The method for preparing a low-aluminum, low-silicon titanium-aluminum based master alloy according to claim 2, characterized in that: In step S1, the low-silicon titanium-containing raw material refers to a raw material with TiO2 ≥ 45% and SiO2 ≤ 0.7%, or a raw material with TiO2 ≥ 45% and SiO2 ≤ 0.7% after an alkaline leaching and silicon removal process; the low-silicon titanium-containing raw material includes but is not limited to high-titanium slag, acid-soluble titanium slag, titanium concentrate, titanium ash powder, titanium yellow powder and titanium dioxide.

4. The method for preparing a low-aluminum, low-silicon titanium-aluminum based master alloy according to claim 2, characterized in that: In step S1, the reducing agent includes but is not limited to at least one of aluminum, calcium and binary composite metals thereof; the flux includes but is not limited to at least one of calcium fluoride, calcium oxide, fluorite, limestone, dolomite and quicklime; the additive includes but is not limited to at least one of iron oxide scale, iron filings, scrap steel and iron ore powder.

5. The method for preparing a low-aluminum, low-silicon titanium-aluminum based master alloy according to claim 3, characterized in that: The alkaline leaching desiliconization process is as follows: the raw material to be treated is dried and mixed with a sodium hydroxide solution at a rate of 4 to 10 mL·g -1 The mixture is added into the reaction vessel at a liquid-to-solid ratio, stirred at a rate of 400-500 r / min and kept warm at 50-95°C for 1.5-3.0 h, then filtered, washed and dried.

6. The method for preparing a low-aluminum, low-silicon titanium-aluminum based master alloy according to claim 5, characterized in that: The raw material was dried at 105°C for 2h; the concentration of the sodium hydroxide solution was 0.5-3.0 mol·L -1 ; Filter and wash until the filtrate pH is 7, and dry at 105℃ for 2h.

7. The method for preparing a low-aluminum, low-silicon titanium-aluminum based master alloy according to claim 1, characterized in that: In step S1, in the mixed material, the mass ratio of CaO / 2Al2O3 is 0.4-0.7, and the mass ratio of CaF2 / (CaF2+Al2O3+CaO) is 0-40%.

8. The method for preparing a low-aluminum, low-silicon titanium-aluminum based master alloy according to claim 7, characterized in that: In step S1, in the mixed material, based on 100 g of TiO2 effective ingredient, the mass range ratio of each effective ingredient is TiO2:Al:CaO:CaF2:Fe=100:45~64:68~129:0~146:0~8.

9. The low-aluminum, low-silicon titanium-aluminum based master alloy prepared by the preparation method according to any one of claims 1 to 8, characterized in that: Its chemical composition by mass percentage is: Ti 70-82%, Al 8-15%, Si 0-0.5%, Fe 0-8%, Mn 0-3%, N≤0.5%, H≤0.3%, O≤0.6%.

10. Application of the low-aluminum and low-silicon titanium-aluminum-based master alloy according to claim 9 in titanium alloy production, characterized in that: According to actual product requirements, the low-aluminum, low-silicon titanium-aluminum based intermediate alloy is refined and modulated to obtain a titanium alloy with the target composition.

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