Method for regulating the properties of vanadium-iron alloy slag and smelting efficiency

Abstract

The present application relates to a kind of methods for regulating vanadium iron alloy slag characteristics and smelting efficiency, steps are: vanadium oxide, first vanadate, aluminum particle, iron filings and lime are mixed to obtain first batch mixture, vanadium oxide, second vanadate, aluminum particle, iron filings and lime are mixed to obtain second batch mixture, and first and second batch mixture are subjected to aluminothermic reaction respectively, electrode auxiliary heating is used after reaction ends;The above operation is repeatedly performed to carry out N period batch feeding and smelting operation, wherein N≥2 and is integer, and lime is supplemented to form slag before the end of smelting in each of the first to N-1 period, and slagging operation is carried out once;After the N period smelting is completed, lime is supplemented to form slag, and slag iron is discharged after slagging ends.The present application makes full use of the advantages of vanadate, such as large heat release, good mass transfer condition, and by adjusting the addition method of slagging agent, the composition of molten slag at different stages is improved, the characteristics of molten slag are improved, so that efficient reduction and separation of smelting process are realized.

Description

Technical Field

[0001] This invention belongs to the field of metallurgy, and more specifically, relates to a method for controlling the characteristics of ferrovanadium alloy slag and smelting efficiency. Background Technology

[0002] Ferrovanadium alloys are widely used in vanadium-containing microalloyed steels. They possess a dual strengthening mechanism of grain refinement and precipitation strengthening, thereby reducing overheating sensitivity and improving the steel's strength and wear resistance. Ferrovanadium alloys are also widely used in construction, aerospace, and road and bridge construction industries. The preparation of ferrovanadium alloys mainly uses vanadium oxides as the vanadium source and ferrous materials as the iron source, employing a (electro)aluminothermic reduction method for high-temperature smelting followed by slag-metal separation. During the smelting process, slag-forming agents are generally added to improve slag characteristics, thereby increasing reduction efficiency, promoting slag-metal separation, and controlling inclusion composition.

[0003] Chinese patent CN102115821A discloses a method for smelting ferrovanadium using the electrothermal process. This method involves mixing metallurgical raw materials such as vanadium oxide, aluminum granules, iron filings, and lime, then performing reduction smelting in a furnace. Slag is removed at the end of the reduction smelting process. After slag removal, iron-based oxides are added to the alloy liquid for dealuminization. This method uses CaO as a slag-forming agent and iron oxides as a dealuminizing agent. Chinese patent CN106282564A discloses a method for refining ferrovanadium alloy by injection. This method involves adding vanadium oxide, aluminum granules, iron granules, lime, and other smelting raw materials in batches to a furnace and smelting them electrically. After smelting, aluminum powder is injected, and refining continues electrically after injection. This method mainly improves injection efficiency and reduces the vanadium content (TV) of the discarded slag by using aluminum powder injection. Chinese patent CN101100720A discloses a production process for smelting ferrovanadium from calcium vanadate. This method involves mixing calcium vanadate, aluminum powder, and iron materials in a certain proportion and then carrying out an aluminothermic reaction to obtain a ferrovanadium alloy product with qualified product quality.

[0004] However, as can be seen from the aforementioned patents, most current ferrovanadium alloy smelting processes involve the addition of a slag-forming agent, primarily composed of alkaline oxides. Furthermore, the high melting point and high viscosity of the slag in current ferrovanadium alloy production processes result in poor reaction thermodynamics, slow reduction rates, and difficulties in alloy settling, all of which negatively impact vanadium reduction and separation efficiency, as well as smelting efficiency.

[0005] Therefore, existing technologies need to be improved. Summary of the Invention

[0006] The purpose of this invention is to overcome the problems in the production process of ferrovanadium alloys, such as poor reaction thermodynamics, slow reduction rate, and difficulty in alloy sedimentation caused by the high melting point and high viscosity of the slag, which affect the reduction and separation effect of vanadium and the smelting efficiency. This invention provides a method for controlling the characteristics of slag and smelting efficiency. This method makes full use of the advantages of vanadates, such as high heat release and good mass transfer conditions. At the same time, by adjusting the way the slag-forming agent is added, the composition of slag at different stages is further improved, and the characteristics of slag are improved, thereby achieving efficient reduction and separation in the smelting process.

[0007] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0008] According to one aspect of the present invention, a method for controlling the characteristics and smelting efficiency of ferrovanadium alloy slag is provided, comprising the following steps:

[0009] 1) Mix vanadium oxide, first vanadate, aluminum granules, iron filings and lime evenly to obtain the first batch of vanadium-iron smelting mixture, and put the first batch of vanadium-iron smelting mixture into a smelting electric furnace for aluminothermic self-propagating reaction. After the reaction is completed, electrode auxiliary heating is used.

[0010] 2) Mix vanadium oxide, second vanadate, aluminum granules, iron filings and lime evenly to obtain the second batch of vanadium-iron smelting mixture. Then, load the second batch of vanadium-iron smelting mixture into a smelting electric furnace to carry out the aluminothermic self-propagating reaction. After the reaction is completed, use electrode auxiliary heating.

[0011] 3) Treat steps 1) and 2) as a batch feeding and smelting operation, and then repeat steps 1) and 2) to carry out N batch feeding and smelting operations, where N≥2 and is an integer. Before the end of each smelting operation from the 1st to the N-1th period, lime is added to form slag, and a slag discharge operation is carried out at the same time.

[0012] 4) After the Nth smelting is completed, lime will be added for slag making. After the slag making is completed, the slag and iron will be discharged together.

[0013] In one embodiment of the present invention, the vanadium oxide is V2O3, V2O5 or a mixture of the two, wherein the content of TV in V2O3 by weight is ≥63%, the content of TV in V2O5 by weight is ≥54%, and the mass ratio of V2O5 to V2O3 is 0-2:8-10.

[0014] In one embodiment of the present invention, the mass ratio of vanadium oxide, first vanadate or second vanadate, aluminum particles, iron filings and lime is 100:0~25:30~73:60~70:10~20.

[0015] In one embodiment of the present invention, the first vanadate is calcium vanadate with different calcium-vanadate ratios, including calcium metavanadate CaV2O6, calcium pyrovanadate Ca2V2O7 and calcium orthovanadate Ca3V2O8.

[0016] In one embodiment of the present invention, the first vanadate is calcium metavanadate CaV2O6 with a calcium to vanadium mass ratio of 1 to 3:10, and its total addition amount in a single furnace accounts for 5 to 15% of the total vanadium oxide addition amount in the furnace.

[0017] In one embodiment of the present invention, the second vanadate is iron vanadate FeVO4, and its total addition amount in a single furnace accounts for 0 to 5% of the total vanadium oxide addition amount in the furnace.

[0018] In one embodiment of the present invention, the amount of lime added in each batch of ferrovanadium smelting mixture is 0-10%, and the amount of lime added before the end of each smelting period from the 1st to the N-1th period is 0-5%.

[0019] In one embodiment of the present invention, the total aluminum content of a single furnace is 1.0 to 1.1 times the theoretical aluminum content, wherein the aluminum content of the first stage, the second to N-1 stages and the Nth stage are 1.0 to 1.4 times, 0.9 to 1.2 times and 0.6 to 1.05 times the theoretical aluminum content, respectively.

[0020] In one embodiment of the present invention, the purity of the aluminum particles is ≥99%, and the particle size is 0.1-1 cm; the purity of the iron filings is ≥99%, and the surface area of ​​the iron filings is ≤5 cm². 2 The CaO content in lime is ≥80%, and the content of metallic impurities in lime is ≤1%.

[0021] In one embodiment of the present invention, a slag discharge operation is performed when the vanadium mass fraction in the smelting slag decreases by a unit alloy power of 400-600 kVA / t until the slag mass fraction decreases by <0.05% / min.

[0022] By adopting the above technical solution, the present invention has the following advantages compared with the prior art:

[0023] This invention uses vanadium oxide and iron filings as the main vanadium-containing raw materials and iron materials, and vanadates as auxiliary agents to regulate slag characteristics and smelting efficiency. By optimizing the auxiliary agents and adjusting the addition system, the vanadium content of the waste slag in ferrovanadium smelting is reduced and the smelting efficiency is improved.

[0024] This invention fully utilizes the advantages of the regulating additives, such as high heat release and good mass transfer conditions, effectively improving the thermodynamic conditions of the smelting process. This is conducive to improving the technical and economic indicators of the smelting system and has significant social and economic benefits. Attached Figure Description

[0025] Figure 1The diagram shows a process flow diagram of a method for controlling the characteristics and smelting efficiency of ferrovanadium alloy slag provided by the present invention. Detailed Implementation

[0026] It should be understood that the embodiments of the invention shown in the exemplary embodiments are merely illustrative. Although only a few embodiments have been described in detail in this invention, those skilled in the art will readily recognize that various modifications are possible without substantially departing from the teachings of the invention. Accordingly, all such modifications should be included within the scope of the invention. Other substitutions, modifications, variations, and deletions can be made to the design, operating conditions, and parameters of the following exemplary embodiments without departing from the spirit of the invention.

[0027] like Figure 1 As shown, the present invention provides a method for controlling the characteristics and smelting efficiency of ferrovanadium alloy slag, comprising the following steps:

[0028] Step S101: Mix vanadium oxide, first vanadate, aluminum granules, iron filings and lime evenly to obtain the first batch of vanadium-iron smelting mixture, and put the first batch of vanadium-iron smelting mixture into a smelting electric furnace for aluminothermic self-propagating reaction. After the reaction is completed, electrode auxiliary heating is used.

[0029] Step S102: Mix vanadium oxide, second vanadate, aluminum granules, iron filings and lime evenly to obtain the second batch of vanadium-iron smelting mixture, and put the second batch of vanadium-iron smelting mixture into the smelting electric furnace to carry out the aluminothermic self-propagating reaction. After the reaction is completed, electrode auxiliary heating is used.

[0030] Step S103: Take steps S101 and S102 as a batch feeding and smelting operation, and then repeat steps S101 and S102 to carry out N batch feeding and smelting operations, where N≥2 and is an integer. Before the end of each smelting operation from the 1st to the N-1th period, lime is added to make slag, and a slag discharge operation is carried out at the same time.

[0031] Step S104: After the Nth smelting is completed, add lime to make slag. After the slag making is completed, the slag and iron are discharged together.

[0032] Through the above-mentioned technical solution of the present invention, the present invention makes full use of the advantages of vanadate having large heat release and good mass transfer conditions. At the same time, by adjusting the addition method of slag-forming agent, the composition of slag at different stages is further improved and the characteristics of slag are improved, thereby achieving efficient reduction and separation in the smelting process.

[0033] In the above method, the vanadium oxide is V2O3, V2O5, or a mixture of the two, wherein the V2O3 contains ≥63% TV by weight, the V2O5 contains ≥54% TV by weight, and the mass ratio of V2O5 to V2O3 is 0-2:8-10. Preferably, the vanadium oxide is V2O3 or a mixture of V2O3 and V2O5.

[0034] In the above method, the mass ratio of vanadium oxide, first vanadate or second vanadate, aluminum granules, iron filings and lime is 100:0~25:30~73:60~70:10~20.

[0035] In the above method, the first vanadate is calcium vanadate with different calcium-vanadium ratios, including calcium metavanadate CaV2O6, calcium pyrovanadate Ca2V2O7 and calcium orthovanadate Ca3V2O8. Preferably, the first vanadate is calcium metavanadate CaV2O6 with a calcium-to-vanadium mass ratio of 1 to 3:10, and its total addition in a single furnace accounts for 5 to 15% of the total vanadium oxides added into the furnace.

[0036] In the above method, the second vanadate is iron vanadate FeVO4, and its total addition in a single furnace accounts for 0 to 5% of the total vanadium oxide addition in the furnace.

[0037] In the above method, the amount of lime added to each batch of ferrovanadium smelting mixture is 0-10%, and the amount of lime supplemented in each period is 0-5%.

[0038] In the above method, the total aluminum content of a single furnace is 1.0 to 1.1 times the theoretical aluminum content, wherein the aluminum content of the first stage, the second to N-1 stages and the Nth stage are 1.0 to 1.4 times, 0.9 to 1.2 times and 0.6 to 1.05 times the theoretical aluminum content, respectively.

[0039] In the above method, the purity of aluminum particles is ≥99%, and the particle size is 0.1-1 cm; the purity of iron filings is ≥99%, and the surface area of ​​iron filings is ≤5 cm². 2 The CaO content in lime is ≥80%, and the content of metallic impurities in lime is ≤1%.

[0040] In the above method, a slag discharge operation is performed when the vanadium mass fraction in the smelting slag decreases by 400-600 kVA / t continuously until the unit alloy power supply is less than 0.05% / min.

[0041] The technical solutions of the present invention will be described in detail below through specific embodiments.

[0042] In this invention, the superior properties of calcium and iron vanadates, such as high exothermic reaction and uniform slag formation, are utilized. Based on the differences in the physicochemical properties of different raw materials, a batch-mixing and feeding method is employed to control the characteristics and settling properties of the slag. During the reduction stage, a mixed smelting mode of calcium vanadate and lime is used to optimize the characteristics of the slag in the initial stage of smelting, resulting in a local excess of CaO content in the slag, thereby significantly reducing the melting point of the slag system. Simultaneously, a small amount of iron vanadate is added during the smelting stage to allow the reduction products V and Fe to rapidly aggregate and grow in the upper slag layer. Depending on the furnace volume and the adjustment of the amount of raw materials added in each batch, the above operations are repeated, performing multiple (N-stage) batch-feeding and smelting operations. Before the end of each stage (1 to N-1 stages), additional lime is added for slag formation, and a slag removal operation is performed, thereby achieving efficient slag-gold separation.

[0043] The present invention provides a method for controlling the characteristics and smelting efficiency of ferrovanadium alloy slag, the specific steps of which are as follows:

[0044] (1) Mix vanadium oxide, first vanadate, aluminum granules, iron filings and lime evenly to obtain the first batch of vanadium-iron smelting mixture. Load the first batch of vanadium-iron smelting mixture into a smelting electric furnace for aluminothermic self-propagating reaction. After the reaction is completed, use electrode auxiliary heating.

[0045] (2) Mix vanadium oxide, second vanadate, aluminum granules, iron filings and lime evenly to obtain the second batch of vanadium-iron smelting mixture. Load the second batch of vanadium-iron smelting mixture into the smelting electric furnace for aluminothermic self-propagating reaction. After the reaction is completed, use electrode auxiliary heating.

[0046] (3) Based on the furnace capacity, repeat the operations of steps (1) and (2) to carry out multiple (N) batch feeding and smelting operations, and add lime to make slag before the end of each (1 to N-1) period, and perform a slag discharge operation at the same time.

[0047] (4) After the last batch (Nth batch) of raw materials is put into the furnace and smelted, lime is added to make slag. After the slag making is completed, the slag and iron are discharged together.

[0048] In the above specific steps, the vanadium oxide is V2O3 and / or V2O5; preferably, the TV in V2O3 is ≥63% and the TV in V2O5 is ≥54%; preferably, the vanadium oxide is V2O3 or a mixture of V2O3 and V2O5; the mass ratio of V2O5 to V2O3 is 0~2:8~10.

[0049] In the above specific steps, the mass ratio of vanadium oxide, first vanadate or second vanadate, aluminum granules, iron filings and lime is 100:0~25:30~73:60~70:10~20.

[0050] In the above specific steps, the first vanadate is calcium vanadate with different calcium-vanadium ratios, including calcium metavanadate (CaV2O6), calcium pyrovanadate (Ca2V2O7), and calcium orthovanadate (Ca3V2O8); preferably, in combination with the staged slag formation characteristics, the calcium vanadate is calcium metavanadate, and its total addition in a single furnace accounts for 5-15% of the total vanadium oxide addition in the furnace, and the actual calcium to vanadium mass ratio of the raw materials in the furnace is 1-3:10.

[0051] In the above specific steps, the second vanadate is iron vanadate (FeVO4), and its total addition in a single furnace accounts for 0 to 5% of the total vanadium oxide addition in the furnace.

[0052] In the above specific steps, the amount of lime added to each batch of material is 0-10%, and the amount of additional lime added before the end is 0-5%.

[0053] In the above specific steps, the total aluminum content of a single furnace is 1.0 to 1.1 times the theoretical aluminum content; the aluminum content of the first, second to N-1 and Nth smelting stages are 1.0 to 1.4 times, 0.9 to 1.2 times and 0.6 to 1.05 times the theoretical aluminum content, respectively.

[0054] In the specific steps described above, the purity of the aluminum particles is ≥99%, and the particle size is 0.1-1 cm; the purity of the iron filings is ≥99%, and the surface area of ​​the iron filings is ≤5 cm². 2 The CaO content in lime is ≥80%, and the content of metallic impurities in lime is ≤1%.

[0055] In the above specific steps, the power supplied per unit alloy during continuous energization is 400-600 kVA / t.

[0056] Example 1

[0057] Vanadium trioxide, vanadium pentoxide, calcium metavanadate, aluminum granules, iron filings, and lime were uniformly mixed in a mass ratio of 30:10:5:20:27:6 as the first batch of raw materials. Vanadium trioxide, vanadium pentoxide, ferric vanadate, aluminum granules, iron filings, and lime were uniformly mixed in a weight ratio of 40:0:0:17:24:6 as the second batch of raw materials. The two batches of mixtures were charged into a smelting electric furnace according to the smelting stages. After the vanadium-iron smelting mixture was completely melted to form a molten pool with no obvious crust on the surface, 2 parts by mass of lime were added for secondary slag formation. Electricity was continuously supplied at a unit alloy power of 400 kVA / t until the vanadium mass fraction in the smelting slag decreased by <0.05% / min, at which point a slag removal operation was performed. After the first phase of smelting is completed, the above-mentioned feeding, smelting and slag removal operations are repeated to carry out multiple phases (N phases) of smelting. After the smelting is completed, an insulation cover is added to the upper surface of the furnace body, and then it is naturally cooled in the air. After the furnace is dismantled, ferrovanadium alloy and smelting slag are obtained.

[0058] In the above method, the actual amount of aluminum particles added in the first to Nth periods is 1.05 times the theoretical amount, and the comprehensive aluminum blending coefficient for a single furnace is 1.05.

[0059] In the above method, the TV content in vanadium trioxide is 66.0%, the TV content in vanadium pentoxide is 55.5%, the purity of calcium metavanadate, iron vanadate, aluminum particles, and iron filings is not less than 99.5%, and the effective component (CaO) content of lime is 86.0%.

[0060] In Example 1 above, the mass fractions of TV and Al2O3 in the smelting slag were 1.2% and 71.4%, respectively, and the mass fractions of V and Al in the ferrovanadium alloy product were 49.7% and 1.4%, respectively.

[0061] Example 2

[0062] Vanadium trioxide, vanadium pentoxide, calcium metavanadate, aluminum granules, iron filings, and lime were uniformly mixed in a mass ratio of 30:10:10:22:28:5 as the first batch of raw materials. Vanadium trioxide, vanadium pentoxide, ferric vanadate, aluminum granules, iron filings, and lime were uniformly mixed in a weight ratio of 40:0:5:19:24:7 as the second batch of raw materials. The two batches of mixtures were charged into a smelting electric furnace according to the smelting stages. After the vanadium-iron smelting mixture was completely melted to form a molten pool with no obvious crust on the surface, 2 parts by mass of lime were added for secondary slag formation. Electricity was continuously supplied at a unit alloy power of 400 kVA / t until the vanadium mass fraction in the smelting slag decreased by <0.05% / min, at which point a slag removal operation was performed. After the first phase of smelting is completed, the above-mentioned feeding, smelting and slag removal operations are repeated to carry out multiple phases (N phases) of smelting. After the smelting is completed, an insulation cover is added to the upper surface of the furnace body, and then it is naturally cooled in the air. After the furnace is dismantled, ferrovanadium alloy and smelting slag are obtained.

[0063] In the above method, the actual amount of aluminum particles added in the first to Nth periods is 1.05 times the theoretical amount, and the comprehensive aluminum blending coefficient for a single furnace is 1.05.

[0064] In the above method, the TV in vanadium trioxide is 66.0%, the TV in vanadium pentoxide is 55.5%, the purity of calcium metavanadate, iron vanadate, aluminum particles, and iron filings is not less than 99.5%, and the content of effective lime component (CaO) is 86.0%.

[0065] In Example 2 above, the mass fractions of TV and Al2O3 in the smelting slag were 1.1% and 71.9%, respectively, and the mass fractions of V and Al in the ferrovanadium alloy product were 50.2% and 1.2%, respectively.

[0066] Example 3

[0067] Vanadium trioxide, vanadium pentoxide, calcium vanadate pyrovanadate, aluminum granules, iron filings, and lime were uniformly mixed in a mass ratio of 30:10:10:25:28:5 as the first batch of raw materials for Phase 1. Vanadium trioxide, vanadium pentoxide, ferric vanadate, aluminum granules, iron filings, and lime were uniformly mixed in a mass ratio of 40:0:5:21:24:7 as the second batch of raw materials for Phase 1. Vanadium trioxide, vanadium pentoxide, calcium vanadate pyrovanadate, aluminum granules, iron filings, and lime were uniformly mixed in a mass ratio of 30:10:10:22:28:5 as the first batch of raw materials for Phases 2 to N-1. Vanadium trioxide, vanadium pentoxide, ferric vanadate, aluminum granules, iron filings, and lime were uniformly mixed in a mass ratio of 40:0:5:19:24:7 as the second batch of raw materials for Phases 2 to N-1. Vanadium trioxide, vanadium pentoxide, calcium vanadate pyrovanadate, aluminum granules, iron filings, and lime were uniformly mixed in a mass ratio of 30:10:10:19:28:5 as the first batch of raw materials for the Nth smelting phase. Vanadium trioxide, vanadium pentoxide, ferric vanadate, aluminum granules, iron filings, and lime were uniformly mixed in a mass ratio of 40:0:5:16:24:7 as the second batch of raw materials for the Nth smelting phase. The two batches of mixtures were charged into a smelting electric furnace for smelting according to the smelting phase. After the vanadium-iron smelting mixture was completely melted to form a molten pool with no obvious crust on the surface, 2 parts by mass of lime were added for secondary slag formation. A unit alloy power supply of 400 kVA / t was continuously applied until the vanadium mass fraction in the smelting slag decreased by <0.05% / min, at which point a slag removal operation was performed. After the first phase of smelting is completed, the above-mentioned feeding, smelting and slag removal operations are repeated to carry out multiple phases (N phases) of smelting. After the smelting is completed, an insulation cover is added to the upper surface of the furnace body, and then it is naturally cooled in the air. After the furnace is dismantled, ferrovanadium alloy and smelting slag are obtained.

[0068] In the above method, the actual amount of aluminum particles added in the first stage is 1.2 times the theoretical amount, the actual amount of aluminum particles added in the second to N-1 stages is 1.05 times the theoretical amount, the actual amount of aluminum particles added in the Nth stage is 0.9 times the theoretical amount, and the comprehensive aluminum blending coefficient for a single furnace is 1.05.

[0069] In the above method, the TV in vanadium trioxide is 66.0%, the TV in vanadium pentoxide is 55.5%, the purity of calcium pyrovanadate, iron vanadate, aluminum particles, and iron filings is not less than 99.5%, and the content of effective lime component (CaO) is 86.0%.

[0070] In Example 3 above, the mass fractions of TV and Al2O3 in the smelting slag were 0.9% and 72.3%, respectively, and the mass fractions of V and Al in the ferrovanadium alloy product were 50.5% and 0.9%, respectively.

[0071] Example 4

[0072] Vanadium trioxide, vanadium pentoxide, calcium orthovanadate, aluminum granules, iron filings, and lime were uniformly mixed in a mass ratio of 30:10:10:29:28:6 as the first batch of raw materials for Phase 1. Vanadium trioxide, vanadium pentoxide, ferric vanadate, aluminum granules, iron filings, and lime were uniformly mixed in a mass ratio of 40:0:5:25:24:8 as the second batch of raw materials for Phase 1. Vanadium trioxide, vanadium pentoxide, calcium orthovanadate, aluminum granules, iron filings, and lime were uniformly mixed in a mass ratio of 30:10:10:22:28:6 as the first batch of raw materials for Phases 2 to N-1. Vanadium trioxide, vanadium pentoxide, ferric vanadate, aluminum granules, iron filings, and lime were uniformly mixed in a mass ratio of 40:0:5:19:24:8 as the second batch of raw materials for Phases 2 to N-1. Vanadium trioxide, vanadium pentoxide, calcium orthovanadate, aluminum granules, iron filings, and lime were uniformly mixed in a mass ratio of 30:10:10:14.5:28:6 as the first batch of raw materials for the Nth smelting phase. Vanadium trioxide, vanadium pentoxide, ferric vanadate, aluminum granules, iron filings, and lime were uniformly mixed in a mass ratio of 40:0:5:12.5:24:8 as the second batch of raw materials for the Nth smelting phase. The two batches of mixtures were charged into a smelting electric furnace for smelting according to the smelting phase. After the vanadium-iron smelting mixture was completely melted to form a molten pool with no obvious crust on the surface, 2 parts by mass of lime were added for secondary slag formation. Electricity was continuously supplied at a unit alloy power of 400 kVA / t until the vanadium mass fraction in the smelting slag decreased by <0.05% / min, at which point a slag removal operation was performed. After the first phase of smelting is completed, the above-mentioned feeding, smelting and slag removal operations are repeated to carry out multiple phases (N phases) of smelting. After the smelting is completed, an insulation cover is added to the upper surface of the furnace body, and then it is naturally cooled in the air. After the furnace is dismantled, ferrovanadium alloy and smelting slag are obtained.

[0073] In the above method, the actual amount of aluminum particles added in the first stage is 1.4 times the theoretical amount, the actual amount of aluminum particles added in the second to N-1 stages is 1.05 times the theoretical amount, the actual amount of aluminum particles added in the Nth stage is 0.7 times the theoretical amount, and the comprehensive aluminum blending coefficient for a single furnace is 1.05.

[0074] In the above method, the TV in vanadium trioxide is 66.0%, the TV in vanadium pentoxide is 55.5%, the purity of calcium orthovanadate, iron vanadate, aluminum granules, and iron filings is not less than 99.5%, and the content of effective lime component (CaO) is 86.0%.

[0075] In Example 4 above, the mass fractions of TV and Al2O3 in the smelting slag were 0.7% and 72.6%, respectively, and the mass fractions of V and Al in the ferrovanadium alloy product were 50.8% and 0.7%, respectively.

[0076] Comparative Example

[0077] Vanadium trioxide, vanadium pentoxide, aluminum granules, iron filings, and lime were uniformly mixed in a mass ratio of 30:10:18:23.5:6 ​​as the first batch of raw materials. The same mixture was then uniformly mixed in a mass ratio of 40:0:17:24:6 as the second batch of raw materials. Both batches were charged into a smelting electric furnace according to the smelting stages. Once the vanadium-iron alloy smelting mixture had completely melted and formed a molten pool with no obvious crust on the surface, 2 parts by mass of lime were added for secondary slag formation. Electricity was continuously supplied at a unit alloy power of 400 kVA / t until the vanadium mass fraction in the smelting slag decreased by <0.05% / min, at which point a slag removal operation was performed. After the first smelting stage, the above feeding, smelting, and slag removal operations were repeated for multiple (N-stage) smelting. After smelting, an insulating cover was added to the upper surface of the furnace, and the furnace was allowed to cool naturally in air. After dismantling, vanadium-iron alloy and smelting slag were obtained.

[0078] In the above method, the actual amount of aluminum particles added in the first to Nth periods is 1.05 times the theoretical amount, and the comprehensive aluminum blending coefficient for a single furnace is 1.05.

[0079] In the above method, the TV in vanadium trioxide is 66.0%, the TV in vanadium pentoxide is 55.5%, the purity of aluminum particles and iron filings is not less than 99.5%, and the content of effective lime component (CaO) is 86.0%.

[0080] Based on the above comparative examples, the mass fractions of TV and Al2O3 in the smelting slag were 1.5% and 68.3%, respectively, while the mass fractions of V and Al in the ferrovanadium alloy products were 49.5% and 1.8%, respectively.

[0081] As can be seen from the above Examples 1-4 and comparative examples, the embodiments of the present invention fully utilize the advantages of vanadate having large heat release and good mass transfer conditions, and further improve the composition of slag at different stages and improve the characteristics of slag by adjusting the addition method of slag-forming agent, thereby achieving efficient reduction and separation in the smelting process.

[0082] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the present invention. Any modifications or equivalent substitutions made to the present invention without departing from the spirit and scope thereof should be covered within the protection scope of the claims of the present invention.

Claims

1. A method for controlling the characteristics and smelting efficiency of ferrovanadium alloy slag, characterized in that, Includes the following steps: 1) Mix vanadium oxide, first vanadate, aluminum granules, iron filings and lime evenly to obtain the first batch of vanadium-iron smelting mixture, and put the first batch of vanadium-iron smelting mixture into a smelting electric furnace for aluminothermic self-propagating reaction. After the reaction is completed, electrode auxiliary heating is used. 2) Mix the vanadium oxide, the second vanadate, the aluminum granules, the iron filings and the lime evenly to obtain the second batch of vanadium-iron smelting mixture, and put the second batch of vanadium-iron smelting mixture into the smelting electric furnace to carry out the aluminothermic self-propagating reaction. After the reaction is completed, electrode auxiliary heating is used. 3) Treat steps 1) and 2) as a batch feeding and smelting operation, and then repeat steps 1) and 2) to carry out N batch feeding and smelting operations, where N≥2 and is an integer. Before the end of each smelting operation in the 1st to N-1th period, lime is added for slag formation, and a slag removal operation is carried out at the same time. 4) After the Nth smelting phase is completed, lime will be added for slag making. After the slag making is completed, the slag and iron will be discharged together. The first vanadate is calcium vanadate with a different calcium-vanadate ratio; the second vanadate is iron vanadate (FeVO4).

2. The method for regulating the characteristics and smelting efficiency of ferrovanadium alloy slag according to claim 1, characterized in that, The vanadium oxide is V2O3, V2O5, or a mixture of both, wherein the mass ratio of V2O5 to V2O3 in the mixture is 0~2:8~10.

3. The method for regulating the characteristics and smelting efficiency of ferrovanadium alloy slag according to claim 1, characterized in that, The mass ratio of the vanadium oxide, the first vanadate or the second vanadate, the aluminum particles, the iron filings and the lime is 100:0~25:30~73:60~70:10~20, and the mass of the first vanadate and the second vanadate is not 0.

4. The method for controlling the characteristics and smelting efficiency of ferrovanadium alloy slag according to claim 1, characterized in that, The calcium vanadate includes calcium metavanadate (CaV2O6), calcium pyrovanadate (Ca2V2O7), and calcium orthovanadate (Ca3V2O8).

5. The method for regulating the characteristics and smelting efficiency of ferrovanadium alloy slag according to claim 4, characterized in that, The first vanadate is calcium metavanadate (CaV2O6), and its total addition mass in a single furnace accounts for 5-15% of the total vanadium oxide addition mass in the furnace.

6. The method for regulating the characteristics and smelting efficiency of ferrovanadium alloy slag according to claim 1, characterized in that, The total mass of the second vanadate added in a single furnace accounts for 0 to 5% of the total mass of vanadium oxides added into the furnace, and the mass of the second vanadate is not 0.

7. The method for controlling the characteristics and smelting efficiency of ferrovanadium alloy slag according to claim 1, characterized in that, The amount of lime added to each batch of ferrovanadium smelting mixture is 0-10%, and the amount of lime added before the end of each smelting period from 1 to N-1 is 0-5%.

8. The method for controlling the characteristics and smelting efficiency of ferrovanadium alloy slag according to claim 1, characterized in that, The total aluminum content per furnace is 1.0 to 1.1 times the theoretical aluminum content, with the aluminum content in the first, second to N-1 and Nth periods being 1.0 to 1.4 times, 0.9 to 1.2 times and 0.6 to 1.05 times the theoretical aluminum content, respectively.

9. The method for controlling the characteristics and smelting efficiency of ferrovanadium alloy slag according to claim 1, characterized in that, The purity of the aluminum particles is ≥99%, and the particle size of the aluminum particles is 0.1-1cm; the purity of the iron filings is ≥99%, and the content of metallic impurities in the lime is ≤1%.

10. The method for regulating the characteristics and smelting efficiency of ferrovanadium alloy slag according to claim 1, characterized in that, A slag removal operation is performed when the vanadium mass fraction in the smelting slag decreases by 400-600 kVA / t continuously until the vanadium mass fraction in the smelting slag decreases by <0.05% / min.

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