A method for preparing ferro-titanium alloy by using waste vanadium-tungsten-titanium catalyst

Abstract

The present invention discloses a method for preparing ferrotitanium alloy by using waste vanadium-tungsten-titanium catalyst, belonging to the technical field of waste catalyst recycling. In the present invention, the catalyst main body and the blockage are separated and ground, and a flux is added and mixed and heated to form an alloy slag; then, a composite reducing agent is added to the alloy slag for thermal reduction. After the reaction is completed, the molten steel is cooled, and the remaining slag on the upper surface of the molten steel is removed to obtain a ferrotitanium alloy containing vanadium and tungsten elements. The method for preparing ferrotitanium alloy in the present invention can not only make full use of valuable elements in waste denitration catalysts by combining carbothermal reduction and aluminothermic reduction to produce a ferrotitanium alloy containing vanadium and tungsten elements; at the same time, it also controls the sequence of occurrence of carbothermal reduction and aluminothermic reduction to reduce the production cost of the reducing agent. In addition, in the present invention, the catalyst components and blockage components of the waste catalyst are fully utilized, and there is no need to consider the subsequent treatment of the blockage in the waste catalyst.

Description

Technical Field

[0001] The present invention belongs to the technical field of waste catalyst recovery, and more specifically, relates to a method for preparing ferro-titanium alloy by using waste vanadium-tungsten-titanium catalyst. Background Art

[0002] NO in flue gas x Treatment has become one of the most concerned environmental protection issues at present. The NH3-SCR method with vanadium-tungsten-titanium catalyst as the core is the most widely used denitrification technology at present, and this technology has been widely applied in thermal power generation, waste incineration, coal-fired boilers and the steel industry. At present, the service life of vanadium-tungsten-titanium catalyst is 2-3 years, and the annual domestic production of waste denitrification catalyst is about 40,000 tons. The waste catalyst contains valuable elements such as vanadium, tungsten and titanium, which have high economic value. At the same time, vanadium and heavy metal elements in the waste catalyst have strong leaching toxicity and are classified as "HW50 hazardous waste". Direct stacking or landfill treatment will cause resource waste and environmental pollution problems.

[0003] At present, the main treatment ideas are the utilization of valuable elements and harmless disposal. The utilization of valuable elements can solve the environmental problems of waste catalysts and at the same time explore the economic value of valuable elements, which has received key attention.

[0004] After retrieval, the application case with the Chinese patent application number 202111422901.6 discloses a method for recovering titanium, vanadium and tungsten from waste SCR denitrification catalyst. This application case uses sulfuric acid as the leaching agent, which can achieve the efficient synchronous leaching of valuable elements titanium, vanadium and tungsten in the waste catalyst; uses a weakly basic extractant to co-extract tungsten and titanium in the leaching solution, uses hydrogen peroxide + sulfuric acid as the anti-titanium agent, and uses ammonia water as the anti-tungsten agent to realize the separation of titanium, tungsten and vanadium in the decomposition solution, and the leaching rate of vanadium-tungsten-titanium elements exceeds 96%. However, in this application case, the sulfuric acid leaching method is adopted, which requires the use of a large amount of acid solution, alkali solution and extractant, the process flow is complex, and the environmental protection pressure is high. Summary of the Invention

[0005] 1. Problems to be Solved

[0006] Aiming at the problem that it is difficult to utilize valuable elements in existing waste denitrification catalysts, the present invention provides a method for preparing ferro-titanium alloy by using waste vanadium-tungsten-titanium catalyst. By adopting the technical scheme of the present invention, the valuable elements in waste denitrification catalysts can be fully utilized to produce ferro-titanium alloy containing vanadium and tungsten elements.

[0007] 2. Technical Scheme

[0008] In order to solve the above problems, the technical scheme adopted by the present invention is as follows:

[0009] A method for preparing ferrotitanium alloy by using waste vanadium-tungsten-titanium catalyst according to the present invention comprises the following steps:

[0010] Step 1: Preparation of alloy slag

[0011] (1) Mechanically separate the catalyst main body and the blockage in the pores. Then, initially crush the waste catalyst, and then perform crushing and grinding on the waste catalyst to grind it into particles with a diameter less than 74 μm; grind the blockage into particles with a diameter less than 150 μm.

[0012] (2) Prepare a flux by configuring different component sodium salts and calcium oxide in a certain proportion;

[0013] (3) Mix and heat the catalyst powder, blockage powder, and flux to form alloy slag;

[0014] Step 2: Preparation of composite reducing agent

[0015] (1) Crush aluminum block particles and grind them with steel balls to obtain electrostatic aluminum powder with appropriate size;

[0016] (2) Mix the electrostatic aluminum powder and activated carbon powder, and make the activated carbon powder adsorb on the surface of the aluminum powder to form a composite reducing agent; this composite reducing agent combines carbothermal reduction and aluminothermal reduction to realize the utilization of vanadium, tungsten, and titanium elements in the waste catalyst; in addition, this composite reducing agent is a double-layer reducing agent, controlling the sequence of occurrence of carbothermal reduction and aluminothermal reduction, realizing the simultaneous reduction of vanadium and tungsten by carbon and titanium by aluminum, and also reducing the production cost of the reducing agent.

[0017] Step 3: Thermal reduction

[0018] After pouring the alloy slag into molten steel, add the composite reducing agent to the alloy slag for thermal reduction;

[0019] Step 4: Cooling and slag skimming

[0020] After the reaction ends, cool the molten steel, and remove the remaining slag on the upper surface of the molten steel to obtain ferrotitanium alloy containing vanadium and tungsten elements.

[0021] Among them, in Step 1, the content of V2O5 in the catalyst is 0.5 - 2.5%, the content of WO3 is 1 - 5%, the content of TiO2 is 70 - 88%, and the content of SiO2 is 3 - 10%; the content of SiO2 in the blockage is 45 - 70%, and the content of CaO is 3 - 10%;

[0022] The flux is composed of CaO, NaCl, and Na₂CO₃. Among them, CaO can regulate the basicity of the molten slag, improve the fluidity of the molten slag and the reduction rates of vanadium oxide, tungsten oxide, and titanium oxide. The molten salts of Na₂CO₃ and NaCl react with oxides such as vanadium pentoxide, tungsten oxide, and titanium dioxide to be converted into sodium salts with low melting points, thereby reducing the melting point of the metallurgical molten slag. Then, through reduction reactions occurring in the slag phase, the vanadium, tungsten, and titanium components in the waste catalyst are reduced and enter the molten steel, thus obtaining a ferrotitanium alloy containing vanadium and tungsten elements.

[0023] Preferably, in the flux, the content of CaO is 65 - 75%, the content of NaCl is 5 - 20%, and the content of Na₂CO₃ is 5 - 20%.

[0024] Preferably, the mass ratio of the catalyst powder, the plugging powder, and the flux is 2:1:1, controlling the basicity of the alloy molten slag within a suitable range to ensure the low melting point of the alloy molten slag, preventing the melting point of the alloy molten slag from rising significantly, the fluidity from becoming poor, resulting in an increase in process energy consumption, affecting the entry of valuable elements in the waste catalyst into the alloy, and affecting the contents of V / W / Ti elements in the alloy.

[0025] Preferably, the heating temperature of the alloy molten slag is 100 °C higher than the melting point temperature of the metallurgical slag.

[0026] Preferably, in step two, the grinding time of the steel beads is greater than 45 min, the diameter of the aluminum particles after grinding is 150 - 300 μm, the diameter of the activated carbon powder particles is less than 45 μm, and the mass ratio of the activated carbon powder to the aluminum powder is 1:20 - 1:15.

[0027] Preferably, in step three, the temperature of the molten steel is 1600 - 1650 °C, and the added masses of the molten steel, the alloy molten slag, and the composite reducing agent are as follows: the mass ratio of the alloy molten slag to the molten steel is 1:4 - 1:3, and the mass ratio of the composite reducing agent to the alloy slag is 1:4 - 1:3.5;

[0028] Preferably, in step four, the slag skimming temperature is 1500 - 1550 °C, and the cooling rate is 3 - 5 °C / 5 min -1 。

[0029] 3. Beneficial effects

[0030] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0031] (1) A method for preparing ferro-titanium alloy using waste vanadium-tungsten-titanium catalyst of the present invention separates the waste catalyst to obtain the catalyst and the blockage, and then obtains the ferro-titanium alloy containing vanadium and tungsten elements through thermal reduction. It can not only dispose of waste denitration catalyst, but also make full use of valuable elements in the waste denitration catalyst. In addition, in the present invention, both the catalyst and the blockage are fully utilized, achieving the full utilization of waste catalyst without considering the subsequent treatment of the blockage in the waste catalyst;

[0032] (2) A method for preparing ferro-titanium alloy using waste vanadium-tungsten-titanium catalyst of the present invention, the flux is composed of CaO, NaCl, and NaCO3. Among them, CaO can regulate the basicity of the molten slag, improve the fluidity of the molten slag and the reduction rate of vanadium oxide, tungsten oxide and titanium oxide. The molten salts of Na2CO3 and NaCl react with oxides such as vanadium pentoxide, tungsten oxide, and titanium dioxide to be converted into low-melting sodium salts, thereby reducing the melting point of the metallurgical molten slag and further promoting the reduction of vanadium, tungsten and titanium elements;

[0033] (3) A method for preparing ferro-titanium alloy using waste vanadium-tungsten-titanium catalyst of the present invention. While refining the aluminum block particles by grinding aluminum powder with steel beads, due to the frictional collision between iron and aluminum, the surface of the aluminum powder becomes electrostatic. After contacting with activated carbon powder, carbon powder is adsorbed on the surface of the aluminum powder particles to form a double-layer composite reducing agent. Then, through the combination of carbothermal reduction and aluminothermic reduction, the utilization of vanadium, tungsten and titanium elements in the waste catalyst is realized. In addition, the composite reducing agent is a double-layer reducing agent, which controls the sequence of carbothermal reduction and aluminothermic reduction, realizes the reduction of vanadium and tungsten by carbon and the reduction of titanium by aluminum, and also reduces the production cost of the reducing agent. Description of the Drawings

[0034] Figure 1 is a flow chart of a method for preparing ferro-titanium alloy using waste vanadium-tungsten-titanium catalyst of the present invention;

[0035] Figure 2 is the structure of the composite reducing agent in the present invention. Detailed Embodiments

[0036] The present invention will be further described below in conjunction with specific embodiments.

[0037] Example 1

[0038] As Figure 1 shown, a method for preparing ferro-titanium alloy using waste vanadium-tungsten-titanium catalyst of this embodiment is as follows:

[0039] Step 1: Treatment of waste catalyst and preparation of alloy molten slag

[0040] (1) Pretreatment of waste catalyst: Mechanically separate the catalyst main body and the blockage in the pores. Then, initially crush the waste catalyst using a jaw crusher, and then perform crushing and grinding on the waste catalyst to grind it into particles with a diameter less than 74 μm (200 mesh), and grind the blockage into particles with a diameter less than 150 μm (100 mesh).

[0041] (2) Prepare a flux composed of CaO, NaCl, and Na2CO3. The mass fraction of CaO in the flux is 70%, the mass fraction of NaCl is 15%, and the mass fraction of Na2CO3 is 15%.

[0042] (3) Use a high-strength mixer to mix the waste catalyst powder, blockage powder, and flux in a mass ratio of 2∶1∶1. Load the mixture into a high-temperature-resistant crucible, and heat the mixed slag using a programmed temperature rise in a vertical tube furnace. The temperature when the slag melts is recorded as the melting point. At the same time, use an RTW-10 melt physical property measuring instrument (rotation method) to measure the viscosity of the slag, and calculate the binary basicity of the slag. The formula for calculating the binary basicity is as follows:

[0043] R = w(CaO) / w(SiO2)

[0044] In the formula, w(CaO) is the mass fraction of CaO in the sample, and w(SiO2) is the mass fraction of SiO2 in the sample.

[0045] Step 2: Preparation of composite reducing agent

[0046] (1) Using aluminum particles with a diameter of 500 μm as raw materials, use steel balls with a diameter of 5 mm, load them into a planetary ball mill with a diameter of 50 cm according to the mass ratio of steel balls to aluminum powder of 2:1, and grind for 45 minutes. Screen out the electrostatic aluminum powder with a particle diameter less than 300 μm;

[0047] (2) Mix the electrostatic aluminum powder and activated carbon powder with a particle diameter less than 45 μm in a mass ratio of 20∶1 to prepare a composite reducing agent.

[0048] Step 3: Thermal reduction

[0049] Heat and melt the ingot in a vertical tube furnace, control the temperature of the molten steel to 1600 °C, and the mass ratio of molten steel: alloy slag: composite reducing agent = 12:4:1. Add the alloy slag to the molten steel to melt it. After the slag is completely melted, add the composite reducing agent to the alloy slag for thermal reduction, and the reduction time is 30 minutes.

[0050] Step 4: Cooling and slag skimming

[0051] After the reaction, use a CW-5300 water cooler at 3 °C for 5 minutes -1Cool the molten steel at a cooling rate. When the temperature of the molten steel reaches 1500 °C, remove the slag on the upper surface of the molten steel to obtain ferro-titanium alloy. After cooling, take samples for retention. The slag removal and cooling processes are carried out under the protection of argon gas, and the gas flow rate is 2 L / min.

[0052] Example 2

[0053] As Figure 1 shown, a method for preparing ferro-titanium alloy by using waste vanadium-tungsten-titanium catalyst in this example is as follows:

[0054] Step 1. Waste catalyst treatment and alloy slag preparation

[0055] (1) Pretreatment of waste catalyst: Mechanically separate the catalyst main body and the blockage in the pores. Then, use a jaw crusher to conduct primary crushing treatment on the waste catalyst, and then conduct crushing and grinding treatment on the waste catalyst to grind it into particles with a diameter less than 74 μm (200 mesh), and grind the blockage into particles with a diameter less than 150 μm (100 mesh).

[0056] (2) Configure a flux composed of CaO, NaCl, and Na2CO3. The mass fraction of CaO in the flux is 65%, the mass fraction of NaCl is 17.5%, and the mass fraction of Na2CO3 is 17.5%.

[0057] (3) Use a powerful mixer to mix the waste catalyst powder, blockage powder, and flux according to a mass ratio of 2:1:1. Load the mixture into a high-temperature resistant crucible, and use a vertical tube furnace to heat the mixed slag with a programmed temperature rise. The temperature when the slag melts is recorded as the melting point. At the same time, use an RTW-10 melt physical property measuring instrument (rotation method) to measure the viscosity of the slag, and calculate the binary basicity of the slag. The binary basicity calculation formula is as follows:

[0058] R = w(CaO) / w(SiO2)

[0059] In the formula, w(CaO) is the mass fraction of CaO in the sample, and w(SiO2) is the mass fraction of SiO2 in the sample.

[0060] Step 2. Preparation of composite reducing agent

[0061] (1) Use aluminum particles with a diameter of 500 μm as raw materials, and use steel balls with a diameter of 8 mm. Load them into a planetary ball mill with a diameter of 50 cm according to a mass ratio of steel balls to aluminum powder of 2:1 and grind for 45 minutes. Screen out the electrostatic aluminum powder with a particle diameter less than 300 μm;

[0062] (2) Mix the electrostatic aluminum powder and activated carbon powder with a particle diameter less than 45 μm according to a mass ratio of 15:1 to prepare a composite reducing agent.

[0063] Step 3: Thermal reduction

[0064] Heat and melt the ingot in a vertical tubular heating furnace, control the molten steel temperature at 1625 °C, and the mass ratio of molten steel: alloy slag: composite reducing agent is 12:4:1. Add the alloy slag into the molten steel to melt it. After the slag is completely melted, add the composite reducing agent to the alloy slag for thermal reduction, and the reduction time is 30 min.

[0065] Step 4: Cooling and slag skimming

[0066] After the reaction ends, use a CW-5300 water cooler to cool the molten steel at a cooling rate of 4 °C every 5 min -1 until the molten steel temperature reaches 1530 °C. Skim the slag on the upper surface of the molten steel to obtain ferrotitanium alloy. After cooling, take samples for retention. The slag skimming and cooling processes are both carried out under the protection of argon gas, and the gas flow rate is 2 L / min.

[0067] Example 3

[0068] As Figure 1 shown, a method for preparing ferrotitanium alloy using waste vanadium-tungsten-titanium catalyst in this example is as follows:

[0069] Step 1: Treatment of waste catalyst and preparation of alloy slag

[0070] (1) Pretreatment of waste catalyst: Mechanically separate the catalyst main body and the blockage in the pores. Then, use a jaw crusher to conduct primary crushing treatment on the waste catalyst, and then conduct crushing and grinding treatment on the waste catalyst to grind it into particles with a diameter less than 74 μm (200 mesh), and grind the blockage into particles with a diameter less than 150 μm (100 mesh).

[0071] (2) Configure a flux composed of CaO, NaCl, and Na2CO3. The mass fraction of CaO in the flux is 75%, the mass fraction of NaCl is 12.5%, and the mass fraction of Na2CO3 is 12.5%.

[0072] (3) Use a high-strength mixer to mix the waste catalyst powder, blockage powder, and flux according to a mass ratio of 2:1:1. Load the mixture into a high-temperature resistant crucible, and use a vertical tubular heating furnace to heat the mixed slag with a programmed temperature rise. The temperature when the slag melts is recorded as the melting point. At the same time, use an RTW-10 melt physical property measuring instrument (rotation method) to measure the viscosity of the slag, and calculate the binary basicity of the slag. The binary basicity calculation formula is as follows:

[0073] R = w(CaO) / w(SiO2)

[0074] In the formula, w(CaO) is the mass fraction of CaO in the sample, and w(SiO2) is the mass fraction of SiO2 in the sample.

[0075] Step 2: Preparation of composite reducing agent

[0076] (1) Using aluminum particles with a diameter of 500 μm as raw materials, and using steel balls with a diameter of 10 mm, load them into a planetary ball mill with a diameter of 50 cm according to the mass ratio of steel balls to aluminum powder of 2:1 and grind for 45 minutes, then screen out the electrostatic aluminum powder with a particle diameter less than 300 μm;

[0077] (2) Mix the electrostatic aluminum powder and activated carbon powder with a particle diameter less than 45 μm according to a mass ratio of 18:1 to prepare a composite reducing agent.

[0078] Step 3: Thermal reduction

[0079] Heat and melt the ingot in a vertical tube furnace, control the temperature of the molten steel to 1650 °C, and the mass ratio of molten steel: alloy slag: composite reducing agent = 12:4:1. Add the alloy slag to the molten steel and melt it. After the slag is completely melted, add the composite reducing agent to the alloy slag for thermal reduction, and the reduction time is 30 minutes.

[0080] Step 4: Cooling and slag skimming

[0081] After the reaction is completed, use a CW-5300 water cooler to cool the molten steel at a cooling rate of 5 °C per 5 minutes -1 until the temperature of the molten steel reaches 1550 °C, then skim the slag on the upper surface of the molten steel to obtain ferrotitanium alloy. After cooling, take samples for retention. The slag skimming and cooling processes are carried out under the protection of argon gas, and the gas flow rate is 2 L / min.

[0082] Comparative Example 1

[0083] The experimental process of this comparative example is the same as that of Example 1, except that: the blockage in the waste catalyst is not utilized, and the experimental results are recorded in Table 1.

[0084] Comparative Example 2

[0085] The experimental process of this comparative example is the same as that of Example 1, except that: CaO is not added to the flux, and the experimental results are recorded in Table 1.

[0086] Comparative Example 3

[0087] The experimental process of this comparative example is the same as that of Example 1, except that: NaCl and Na2CO3 are not added to the flux, and the experimental results are recorded in Table 1.

[0088] Comparative Example 4

[0089] The experimental process of this comparative example is the same as that of Example 1, except that: aluminum powder is not added to the reducing agent, and the experimental results are recorded in Table 1.

[0090] Comparative Example 5

[0091] The experimental process of this comparative example was the same as that of Example 1, except that: no carbon powder was added to the reducing agent. The experimental results are recorded in Table 1.

[0092] Table 1. Properties of alloy slag and main components of ferrotitanium alloy for each example and comparative example

[0093]

[0094]

[0095] By analyzing the indexes in Table 1, it can be seen that:

[0096] (1) Comparing Comparative Example 1 with Example 1, no plugging powder was added to the alloy slag. The melting point of the alloy slag increased by 200 °C, the viscosity increased by 1.09 Pa·s, the basicity increased by 8.96, the content of Ti element in the ferrotitanium alloy decreased by 1.54%, the content of V element decreased by 0.06%, and the content of W element decreased by 0.12%;

[0097] (2) Comparing Comparative Example 2 with Example 1, no CaO was added to the flux. The melting point of the alloy slag increased by 206 °C, the viscosity increased by 0.84 Pa·s, the basicity decreased by 0.93, the content of Ti element in the ferrotitanium alloy decreased by 2.94%, the content of V element decreased by 0.1%, and the content of W element decreased by 0.19%;

[0098] (3) Comparing Comparative Example 3 with Example 1, no NaCl and Na2CO3 were added to the flux. The melting point of the alloy slag increased by 225 °C, the viscosity increased by 0.94 Pa·s, the content of Ti element in the ferrotitanium alloy decreased by 1.63%, the content of V element decreased by 0.1%, and the content of W element decreased by 0.19%;

[0099] (4) Comparing Comparative Example 4 with Example 1, no aluminum powder was added to the composite reducing agent. Since TiO2 belongs to a refractory reducible phase and cannot be reduced by carbothermal reduction, the alloy made does not contain Ti;

[0100] (5) Comparing Comparative Example 5 with Example 1, no carbon powder was added to the composite reducing agent. The Ti content in the alloy made decreased by 0.63%.

[0101] The applicant's research has found that the basicity of alloy slag is extremely important for the carbothermal reduction and aluminothermic reduction processes. By using CaO and SiO2 (the plug contains a large amount of SiO2, which is the main component of alloy slag) to prepare the slag, within an appropriate range, the viscosity of the alloy slag can be reduced and the fluidity of the alloy slag can be enhanced, thereby optimizing the kinetic conditions of the reduction reaction. The applicant has proven through a large number of experiments that when the basicity of the alloy slag is 0.8 - 1.1, the fluidity of the alloy slag is the best. When the SiO2 content is relatively high, a spatial network structure composed of silicon dioxide will form in the slag. Each particle in the network structure is restricted by ionic bond forces and cannot move freely. When a certain amount of CaO is added, Ca 2+ and O 2- will react with SiO2 to break the network structure and improve the fluidity of the metallurgical slag. However, when the CaO content is too high, CaO, as a high-melting-point substance, will form precipitates in the slag, reducing the fluidity of the metallurgical slag. Therefore, in the present invention, by adding CaO to the flux, the basicity of the alloy slag is adjusted to optimize the fluidity of the slag and the mass transfer conditions between vanadium pentoxide, tungsten oxide, and titanium dioxide and the reducing agent in the slag. By adding NaCl and Na2CO3 to the flux, the purpose is to react the molten salts of Na2CO3 and NaCl with oxides such as vanadium pentoxide, tungsten oxide, and titanium dioxide to convert them into low-melting-point sodium salts, prepare a low-melting-point alloy slag, and through the reduction reaction occurring in the slag phase, reduce the vanadium, tungsten, and titanium components in the waste catalyst into the molten steel, thereby obtaining a ferrotitanium alloy containing vanadium and tungsten elements.

[0102] In the present invention, waste catalysts are used as raw materials for producing ferrotitanium alloy. The content of titanium dioxide as a carrier can reach more than 70%, and the contents of vanadium pentoxide and tungsten oxide can reach about 5%. When using a reducing agent to reduce the valuable metal oxides in the waste catalyst, carbon can reduce vanadium pentoxide and tungsten oxide. The initial temperature for the reduction of vanadium pentoxide and carbon is 1103.7 °C, and the initial temperature for the reduction of tungsten oxide and carbon is 697.4 °C. Titanium dioxide does not react with carbon below 1800 °C. When aluminum is selected as the reducing agent, vanadium pentoxide, tungsten oxide, and titanium dioxide can spontaneously undergo reduction reactions at room temperature to form vanadium, tungsten, and titanium. Based on the above thermodynamic analysis, the applicant uses steel balls to grind aluminum powder, causing electrostatic effects on the surface of the aluminum powder. After contacting with fine carbon powder, the carbon powder is adsorbed on the surface of the aluminum powder particles by electrostatic forces to form a composite reducing agent. After the composite reducing agent enters the alloy slag, the carbon on the surface first reduces the vanadium and tungsten in the catalyst into elemental forms. After the aluminum core of the composite reducing agent contacts the alloy slag, it further reduces titanium dioxide. Using the composite reducing agent fully considers the reduction properties of vanadium, tungsten, and titanium elements in the waste catalyst. The external carbon powder can reduce the amount of the reducing agent aluminum, reducing the production cost.

[0103] It should be noted that in the above experiments, the waste catalyst is the waste generated in the SCR denitration system of coal-fired power plant flue gas. The mass percentage composition thereof is: TiO2: 87.27%, WO3: 4.66%, SiO2: 3.64%, CaO: 1.32%, Al2O3: 0.87%, V2O5: 0.52%, Sx: 0.43%, P: 0.07%, Na: 0.09%, K: 0.07%, and the rest are inevitable impurities; the plugging powder is the solid particulate matter deposited in the SCR denitration catalyst of coal-fired power plant flue gas. The mass percentage composition thereof is: SiO2: 67.64%, Al2O3: 15.41%, Sx: 4.41%, Fe2O3: 4.25%, CaO: 3.80%, K2O: 1.87%, TiO2: 1.19%, Na2O: 0.91%, MgO: 0.67%, P: 0.07%, and the rest are inevitable impurities;

[0104] In addition, the CaO, NaCl and Na2CO3 are all analytical pure reagents with a substance purity > 99%, and the rest are inevitable impurities; the aluminum particles are metallic aluminum with a purity > 99%, and the rest are inevitable impurities; the main components and mass fractions of the activated carbon are: C: 76.59, CaO: 1.14%, SiO2: 11.96%, Al2O3: 6.03%, K: 0.27%, Na: 0.16%, and the rest are inevitable impurities; the main components and mass fractions of the ingot are: C: 0.15%, Mn: 0.52%, Si: 0.12%, S: 0.01%, P: 0.01%, Fe: 99.0%, and the rest are inevitable impurities.

[0105] The present invention and its embodiments are schematically described above. The description is not restrictive. What is shown in the drawings is only one of the embodiments of the present invention, and the actual structure is not limited thereto. Therefore, if those of ordinary skill in the art are inspired by it and design similar structural modes and embodiments without creative work without departing from the purpose of the present invention, they shall fall within the protection scope of the present invention.

Claims

1. A method for preparing ferro-titanium alloy by using waste vanadium-tungsten-titanium catalyst, characterized in that, It includes the following steps: Step 1: Preparation of alloy molten slag a. Mechanically separate the catalyst main body and the blockage in the pores, and grind the catalyst and the blockage; b. Prepare a flux by mixing sodium salt and calcium oxide in proportion; c. Heat and mix the flux, the ground catalyst, and the blockage powder to form alloy molten slag; Step 2: Thermal reduction After pouring the alloy molten slag into the molten steel, add a composite reducing agent to the alloy molten slag for thermal reduction; Step 3: Cooling and slag skimming After the reaction ends, cool the molten steel, and remove the remaining molten slag on the upper surface of the molten steel to obtain a ferrotitanium alloy containing vanadium and tungsten elements; In the above Step 1, the flux is composed of CaO, NaCl, and NaCO3, where the CaO content is 65 - 75%, the NaCl content is 5 - 20%, and the NaCO3 content is 5 - 20%; the V2O5 content in the catalyst is 0.5 - 2.5%, the WO3 content is 1 - 5%, the TiO2 content is 70 - 88%, and the SiO2 content is 3 - 10%; the SiO2 content in the blockage is 45 - 70%, and the CaO content is 3 - 10%; and the mass ratio of the catalyst, the blockage, and the flux is 2:1:

1.

2. The method for preparing ferrotitanium alloy by using waste vanadium-tungsten-titanium catalyst according to claim 1, wherein: In the above Step 1, the particle diameter of the ground catalyst is less than 200 mesh, and the particle diameter of the ground blockage is less than 100 mesh.

3. A method for preparing ferro-titanium alloy by using waste vanadium-tungsten-titanium catalyst according to claim 2, characterized in that: In the above Step 1, the heating temperature of the alloy molten slag is 100°C higher than the melting point temperature of the metallurgical slag.

4. A method for preparing ferrotitanium alloy by using waste vanadium-tungsten-titanium catalyst according to any one of claims 1-3, characterized in that: In the above Step 2, crush and grind aluminum block particles to obtain electrostatic aluminum powder, mix the electrostatic aluminum powder and activated carbon powder, and make the activated carbon powder adsorb on the surface of the aluminum powder to form a composite reducing agent.

5. A method for preparing ferro-titanium alloy by using waste vanadium-tungsten-titanium catalyst according to claim 4, characterized in that: In the above Step 2, use steel beads for grinding, the grinding time is more than 45 min, the diameter of the ground aluminum particles is 150 μm - 300 μm, the diameter of the activated carbon powder particles is less than 45 μm, and the mass ratio of the activated carbon powder to the aluminum powder is 1:20 - 1:

15.

6. A method for preparing ferro-titanium alloy by using waste vanadium-tungsten-titanium catalyst according to claim 5, characterized in that: In the above Step 2, the temperature of the molten steel is 1600 - 1650°C, the mass ratio of the alloy molten slag to the molten steel is 1:4 - 1:3, and the mass ratio of the composite reducing agent to the alloy molten slag is 1:4 - 1:3.

5.

7. A method for preparing ferrotitanium alloy by using waste vanadium-tungsten-titanium catalyst according to claim 6, characterized in that: In the third step described above, the slag skimming temperature is 1500 - 1550 °C, and the cooling rate is 3 - 5 °C·min -1 .

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