Method for directly preparing ferrovanadium alloy from ammonium vanadate

Abstract

The invention discloses a method for directly preparing ferrovanadium by taking ammonium vanadate as a raw material. The method comprises the steps of raw material pretreatment, vacuum heating decomposition, furnace charge mixing and aluminothermic reduction smelting. In the step of vacuum heating decomposition, the pretreated ammonium vanadate is loaded into a double-cone rotary vacuum dryer to be subjected to vacuum heating, so that the pretreated ammonium vanadate is decomposed, ammonia gas and water vapor are released, and a decomposition product with V2O4 and V2O5 as main components is obtained; the step of mixing the furnace charge comprises the following steps: uniformly mixing a decomposition product with aluminum powder, lime, iron powder and a cold charge according to the mass ratio of (60-120): (30-65): (6-10): (6-10): (6-15) based on the mass of V2O5; in the aluminothermic reduction smelting, a magnesium rod is used for igniting furnace charge to carry out aluminothermic reaction; and after the reaction is finished, cooling to room temperature to obtain the ferrovanadium alloy. The method can effectively simplify the process flow, reduce the production cost, improve the product quality, and solve the technical problems of tedious steps and high cost of the traditional process.

Description

Technical Field

[0001] This invention belongs to the field of vanadium-iron alloy preparation technology, specifically relating to a method for directly preparing vanadium-iron alloy using ammonium vanadate. Background Technology

[0002] Ferrovanadium alloys are important alloying additives in the steel industry, widely used in the production of high-strength steel, stainless steel, and other products. In the traditional preparation process of ferrovanadium alloys, if ammonium vanadate is used as a raw material, it must first be converted into vanadium pentoxide through roasting, decomposition, and other processes. Then, vanadium pentoxide is used as the vanadium source to undergo an aluminothermic reaction with aluminum powder, iron, and other ingredients to prepare ferrovanadium alloys.

[0003] The traditional process has the following drawbacks: the intermediate conversion step increases the production steps and prolongs the production cycle; the roasting and decomposition process consumes a large amount of energy, increasing production costs; and multiple processing steps easily lead to vanadium loss, affecting product yield and quality. Therefore, developing a simple, cost-effective, and quality-improving method for preparing ferrovanadium alloys is of great significance. Summary of the Invention

[0004] The purpose of this invention is to provide a method for directly preparing ferrovanadium alloys using ammonium vanadate, which can solve the problems of cumbersome steps, high cost, and easy loss of vanadium in traditional processes.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows: A method for directly preparing ferrovanadium alloys using ammonium vanadate as raw material includes raw material pretreatment, vacuum heating decomposition, furnace charge mixing, and aluminothermic reduction smelting.

[0006] Furthermore, the purity of the ammonium vanadate raw material is ≥98%.

[0007] Furthermore, the raw material pretreatment involves using a combination of magnetic separation and sieving to remove metal impurities and particles larger than 120 mesh, resulting in pretreated ammonium vanadate.

[0008] Furthermore, the vacuum heating decomposition involves loading pretreated ammonium vanadate into a double-cone rotary vacuum dryer for vacuum heating, causing it to decompose and release ammonia and water vapor, resulting in decomposition products with V2O4 and V2O5 as the main components.

[0009] Furthermore, the vacuum heating decomposition is performed with a vacuum degree of 0.06-0.1 MPa, a heating temperature of 130-260℃, and a holding time of 2-4 hours.

[0010] Furthermore, the furnace charge mixing involves mixing the decomposition products, based on the mass of V2O5, with aluminum powder, lime, iron powder, and cold materials in a mass ratio of (60-120):(30-65):(6-10):(6-10):(6-15) until homogeneous.

[0011] Furthermore, the aluminum powder has a purity of ≥99% and a particle size of 100-150 mesh; the lime is industrial-grade quicklime with a particle size ≤5mm; and the iron powder has a purity of ≥98% and a particle size of 50-100 mesh.

[0012] Furthermore, the aluminothermic reduction smelting involves using magnesium strips to ignite the furnace charge for an aluminothermic reaction, followed by cooling to room temperature after the reaction to obtain the ferrovanadium alloy product.

[0013] The beneficial effects of the technical solution of this invention are as follows: The method of this invention eliminates the intermediate step of converting ammonium vanadate into vanadium pentoxide, reducing the number of process steps by more than 30%, shortening the production cycle by 20%-40%, and significantly improving production efficiency.

[0014] The method of this invention can avoid energy consumption and vanadium loss in the intermediate conversion process, increase vanadium recovery rate by 2%-5%, and reduce production cost by 15%-25%.

[0015] This invention employs a vacuum decomposition process, which reduces the introduction of impurities, stabilizes the vanadium content in the ferrovanadium alloy at 78%-82%, and reduces the impurity content to less than 0.5%, significantly improving product quality.

[0016] The process is simple and easy to operate, making it suitable for large-scale industrial production and with broad application prospects. Detailed Implementation

[0017] The technical solution of the present invention will be further described in detail below with reference to the embodiments.

[0018] The aluminum powder used in each embodiment has a purity of ≥99% and a particle size of 100-150 mesh; the lime used is industrial grade quicklime with a particle size ≤5mm; and the iron powder used has a purity of ≥98% and a particle size of 50-100 mesh. Example 1

[0019] A method for directly preparing ferrovanadium alloys from ammonium vanadate includes raw material pretreatment, vacuum heating decomposition, furnace charge mixing, and aluminothermic reduction smelting; details are as follows: (1) Raw material pretreatment: Weigh 80 kg of ammonium metavanadate with a purity ≥ 98%, and remove metal impurities and particles with a particle size greater than 120 mesh by a combination of magnetic separation and sieving to obtain pretreated ammonium metavanadate.

[0020] (2) Vacuum heating decomposition: Pretreated ammonium vanadate was loaded into a double cone rotary vacuum dryer, evacuated to -0.06 MPa, and then heated to 140°C at 3°C / min and held for 40 minutes; then heated to 200°C at 2°C / min and held for 2 hours. After decomposition, it was cooled to 80°C to obtain about 65 kg of brown-black decomposition product, the main components of which were V2O4 and V2O5, equivalent to about 60 kg of V2O5.

[0021] (3) Furnace charge batching: The above decomposition products, based on the mass of V2O5, are added to the mixer along with aluminum powder, lime, iron powder and cold material in a mass ratio of 60:30:6:6:6 and mixed for 30 minutes until the furnace charge is uniform.

[0022] (4) Aluminothermic reduction smelting: The aluminothermic reaction is carried out by igniting the furnace charge with magnesium strips. After the reaction is completed, the furnace charge is cooled to room temperature to obtain a FeV80 alloy ingot weighing about 45 kg.

[0023] Testing revealed that the FeV80 alloy comprises: V: 79.5%, Si: 0.92%, Al: 1.75%, C: 0.05%, P: 0.03%, S: 0.02%, with the remainder being Fe. The alloy is dense, non-porous, and has a vanadium yield of 95.25%. Example 2

[0024] A method for directly preparing ferrovanadium alloys from ammonium vanadate includes raw material pretreatment, vacuum heating decomposition, furnace charge mixing, and aluminothermic reduction smelting; details are as follows: (1) Raw material pretreatment: Weigh 100kg of ammonium metavanadate with a purity ≥98%, and use a combination of magnetic separation and sieving to remove metal impurities and particles with a particle size greater than 120 mesh to obtain pretreated ammonium metavanadate.

[0025] (2) Vacuum heating decomposition: Pretreated ammonium vanadate was loaded into a double cone rotary vacuum dryer, evacuated to -0.08 MPa, and then heated to 140°C at 5°C / min and held for 40 minutes; then heated to 220°C at 3°C / min and held for 2 hours. After decomposition, the product was cooled to 80°C to obtain about 85 kg of brownish-black decomposition product, the main components of which were V2O4 and V2O5, equivalent to about 75 kg of V2O5.

[0026] (3) Furnace charge mixing: The above decomposition products, based on the mass of V2O5, are added to the mixer along with aluminum powder, lime, iron powder and cold material at a mass ratio of 75:40:8:8:8 and mixed for 40 minutes until the furnace charge is uniform.

[0027] (4) Aluminothermic reduction smelting: The aluminothermic reaction is carried out by igniting the furnace charge with magnesium strips. After the reaction is completed, the furnace charge is cooled to room temperature to obtain a FeV80 alloy ingot weighing about 55 kg.

[0028] The alloy composition, as determined by testing, is as follows: V: 80.2%, Si: 0.84%, Al: 1.43%, C: 0.04%, P: 0.02%, S: 0.02%, with the remainder being Fe. The alloy is dense, non-porous, and has a vanadium yield of 95.58%. Example 3

[0029] A method for directly preparing ferrovanadium alloys from ammonium vanadate includes raw material pretreatment, vacuum heating decomposition, furnace charge mixing, and aluminothermic reduction smelting; details are as follows: (1) Raw material pretreatment: Weigh 120 kg of ammonium metavanadate with a purity ≥ 98%, and use a combination of magnetic separation and sieving to remove metal impurities and particles with a particle size greater than 120 mesh to obtain pretreated ammonium metavanadate.

[0030] (2) Vacuum heating decomposition: Pretreated ammonium vanadate was loaded into a double cone rotary vacuum dryer, evacuated to -0.09 MPa, and then heated to 130°C at 5°C / min and held for 30 minutes; then heated to 220°C at 2°C / min and held for 3 hours. After decomposition, the product was cooled to 80°C to obtain about 100 kg of brownish-black decomposition product, the main components of which were V2O4 and V2O5, equivalent to about 90 kg of V2O5.

[0031] (3) Furnace charge mixing: The above decomposition products, based on the mass of V2O5, are added to the mixer along with aluminum powder, lime, iron powder and cold material in a mass ratio of 90:47:9:9:10 and mixed for 40 minutes until the furnace charge is uniform.

[0032] (4) Aluminothermic reduction smelting: The aluminothermic reaction is carried out by igniting the furnace charge with magnesium strips. After the reaction is completed, the furnace charge is cooled to room temperature to obtain a FeV80 alloy ingot weighing about 65 kg.

[0033] The alloy composition, as determined by testing, is as follows: V: 80.52%, Si: 0.91%, Al: 1.36%, C: 0.04%, P: 0.03%, S: 0.04%, with the remainder being Fe. The alloy is dense, non-porous, and has a vanadium yield of 95.82%. Example 4

[0034] A method for directly preparing ferrovanadium alloys from ammonium vanadate includes raw material pretreatment, vacuum heating decomposition, furnace charge mixing, and aluminothermic reduction smelting; details are as follows: (1) Raw material pretreatment: Weigh 150 kg of ammonium metavanadate with a purity ≥ 98%, and remove metal impurities and particles with a particle size greater than 120 mesh by a combination of magnetic separation and sieving to obtain pretreated ammonium metavanadate.

[0035] (2) Vacuum heating decomposition: Pretreated ammonium vanadate was loaded into a double cone rotary vacuum dryer, evacuated to -0.1 MPa, and then heated to 160°C at 5°C / min and held for 60 minutes; then heated to 230°C at 2°C / min and held for 3 hours. After decomposition, it was cooled to 80°C to obtain about 120 kg of brownish-black decomposition products, the main components of which were V2O4 and V2O5, equivalent to about 115 kg of V2O5.

[0036] (3) Furnace charge mixing: The above decomposition products, based on the mass of V2O5, are added to the mixer along with aluminum powder, lime, iron powder and cold material in a mass ratio of 115:65:10:10:15 and mixed for 40 minutes until the furnace charge is uniform.

[0037] (4) Aluminothermic reduction smelting: The aluminothermic reaction is carried out by igniting the furnace charge with magnesium strips. After the reaction is completed, the furnace charge is cooled to room temperature to obtain a FeV80 alloy ingot weighing about 75 kg.

[0038] The alloy composition, as determined by testing, is as follows: V: 80.85%, Si: 0.90%, Al: 1.24%, C: 0.04%, P: 0.03%, S: 0.03%, with the remainder being Fe. The alloy is dense, non-porous, and has a vanadium yield of 96.25%. Example 5

[0039] A method for directly preparing ferrovanadium alloys from ammonium vanadate includes raw material pretreatment, vacuum heating decomposition, furnace charge mixing, and aluminothermic reduction smelting; details are as follows: (1) Raw material pretreatment: Weigh 100kg of ammonium metavanadate with a purity ≥98%, and use a combination of magnetic separation and sieving to remove metal impurities and particles with a particle size greater than 120 mesh to obtain pretreated ammonium metavanadate.

[0040] (2) Vacuum heating decomposition: Pretreated ammonium vanadate was loaded into a double cone rotary vacuum dryer, evacuated to -0.1 MPa, and then heated to 140°C at 5°C / min and held for 60 minutes; then heated to 250°C at 2°C / min and held for 3 hours. After decomposition, the product was cooled to 80°C to obtain about 85 kg of brownish-black decomposition product, the main components of which were V2O4 and V2O5, equivalent to about 75 kg of V2O5.

[0041] (3) Furnace charge mixing: The above decomposition products, based on the mass of V2O5, are added to the mixer along with aluminum powder, lime iron powder and cold material at a mass ratio of 75:40:6:8:12 and mixed for 50 minutes until the furnace charge is uniform.

[0042] (4) Aluminothermic reduction smelting: The aluminothermic reaction is carried out by igniting the furnace charge with magnesium strips. After the reaction is completed, the furnace charge is cooled to room temperature to obtain a FeV80 alloy ingot weighing about 78 kg.

Claims

1. A method for directly preparing ferrovanadium alloys using ammonium vanadate as a raw material, characterized in that, The process includes raw material pretreatment, vacuum heating decomposition, furnace charge mixing, and aluminothermic reduction smelting. The vacuum heating decomposition involves loading pretreated ammonium vanadate into a double-cone rotary vacuum dryer for vacuum heating, causing it to decompose and release ammonia and water vapor, resulting in decomposition products with V2O4 and V2O5 as the main components.

2. The method for directly preparing ferrovanadium alloy using ammonium vanadate as a raw material according to claim 1, characterized in that, The purity of the ammonium vanadate raw material is ≥98%.

3. The method for directly preparing ferrovanadium alloy using ammonium vanadate as a raw material according to claim 1, characterized in that, The raw material pretreatment involves using a combination of magnetic separation and sieving to remove metal impurities and particles larger than 120 mesh, resulting in pretreated ammonium vanadate.

4. The method for directly preparing ferrovanadium alloy using ammonium vanadate as a raw material according to claim 1, characterized in that, The vacuum heating decomposition is performed with a vacuum degree of 0.06-0.1 MPa, a heating temperature of 130-260℃, and a holding time of 2-4 hours.

5. The method for directly preparing ferrovanadium alloy using ammonium vanadate as a raw material according to claim 1, characterized in that, The furnace charge mixing: The decomposition products, based on the mass of V2O5, are mixed evenly with aluminum powder, lime, iron powder, and cold material in a mass ratio of (60-120):(30-65):(6-10):(6-10):(6-15).

6. The method for directly preparing ferrovanadium alloy using ammonium vanadate as a raw material according to claim 5, characterized in that, The aluminum powder has a purity of ≥99% and a particle size of 100-150 mesh; the lime is industrial grade quicklime with a particle size ≤5mm; and the iron powder has a purity of ≥98% and a particle size of 50-100 mesh.

7. The method for directly preparing ferrovanadium alloy using ammonium vanadate as a raw material according to claim 1, characterized in that, The aluminothermic reduction smelting process involves using magnesium strips to ignite the furnace charge for an aluminothermic reaction; after the reaction is completed, the charge is cooled to room temperature to obtain a vanadium-iron alloy.