A method for improving the viscous flow characteristics of high-titanium slag carbonization process and increasing the carbonization rate

Abstract

This invention provides a method for improving the viscous flow characteristics and increasing the carbonization rate of high-titanium slag during the carbonization process, belonging to the field of metallurgical resource comprehensive utilization technology. The steps include: classifying the carbonaceous reducing agent into three particle sizes: fine, medium, and coarse; heating the high-titanium slag to a molten state in an induction furnace and adding the fine-particle carbonaceous reducing agent for initial reaction; then adding the medium-particle carbonaceous reducing agent for further reaction, while continuously blowing inert gas above the molten pool; finally adding the coarse-particle carbonaceous reducing agent for further reaction, while intermittently blowing inert gas above the molten pool; after the reaction is completed, a high-titanium slag carbonization product with improved viscous flow characteristics and increased carbonization rate is obtained. The method provided by this invention achieves improved viscous flow characteristics of the high-titanium slag melt, reduced foaming slag, reduced reducing agent dosage, and increased carbonization rate through the synergistic effect of carbonaceous reducing agent particle size classification, staged feeding, induction furnace melting, and inert gas stirring.

Description

Technical Field

[0001] This invention relates to the field of comprehensive utilization of metallurgical resources, and in particular to a method for improving the viscosity and flow characteristics of high-titanium slag carbonization process and increasing the carbonization rate. Background Technology

[0002] High-titanium slag is an important titanium-containing material formed during the smelting of vanadium-titanium magnetite and the comprehensive utilization of titanium resources. It typically contains a high content of titanium oxides, along with various oxide components such as CaO, SiO2, Al2O3, and MgO. Due to the high titanium content and large reserves in high-titanium slag, its efficient utilization is of great significance for improving the comprehensive recovery level of titanium resources, reducing the pressure of solid waste storage, and promoting the resource utilization of metallurgical solid waste.

[0003] Currently, carbonization treatment to promote the conversion of titanium oxides in high-titanium slag is one of the important technical approaches to achieve high-value utilization of high-titanium slag. Through the carbonization reaction, the titanium oxides in high-titanium slag can gradually undergo reduction and carbonization transformation, creating conditions for the subsequent enrichment, separation, and extraction of titanium components. Therefore, the reaction efficiency and stability of the carbonization process directly affect the techno-economic benefits of utilizing high-titanium slag.

[0004] However, high-titanium slag generally suffers from poor viscosity and low carbonization rate during the carbonization process. On the one hand, the high titanium oxide content in high-titanium slag results in a complex internal melt structure, which tends to exhibit high viscosity and poor flowability under high-temperature carbonization conditions. This restricts the contact, diffusion, and interface renewal between reactants, hindering the continuous carbonization reaction. On the other hand, a large amount of gas is generated during carbonization. When the melt viscosity is high, bubbles are not easily released in time and tend to accumulate in the slag, forming a foam layer. This further deteriorates the melt flow state and the heat and mass transfer conditions in the furnace, leading to uneven local reactions and increased system fluctuations, thus affecting the full progress of the carbonization reaction.

[0005] In existing technologies, to improve the carbonization reaction rate, methods such as increasing the reaction temperature or increasing the amount of carbonaceous reducing agent are usually adopted. However, such methods are prone to problems such as excessively violent local reactions, increased instantaneous gas release, thickened foam layer, and increased power consumption. It is difficult to simultaneously improve the viscosity and flow characteristics of high titanium slag melt and increase the carbonization rate.

[0006] Therefore, there is an urgent need for a new reduction and carbonization method for high-titanium slag to improve the viscous flow characteristics of high-titanium slag melt and increase the carbonization rate of high-titanium slag during the reduction and carbonization process. Summary of the Invention

[0007] This invention aims to address common problems in the carbothermic reduction process of high-titanium slag, such as melt thickening, deterioration of fluidity, unstable foam slag, insufficient mass transfer efficiency, and low carbonization rate. It proposes a method to improve the viscous flow characteristics and increase the carbonization rate of high-titanium slag carbonization process, so as to achieve unified optimization of the physical properties of the high-titanium slag molten pool, reaction kinetics, and process stability.

[0008] To address the aforementioned technical problems, this invention provides a method for improving the viscosity and flow characteristics of high-titanium slag during carbonization and increasing the carbonization rate, comprising the following steps: Carbonaceous reducing agents were classified by particle size to obtain three particle sizes: fine, medium, and coarse. After heating the high-titanium slag to a molten state in an induction furnace, a fine-grained carbonaceous reducing agent is added for initial reaction. Then add medium-sized carbonaceous reducing agent to react, and continuously spray inert gas above the molten pool; Finally, coarse-grained carbonaceous reducing agent is added to react, and inert gas is intermittently injected above the molten pool; After the reaction is completed, a high-titanium slag carbonization product with improved viscosity and increased carbonization rate is obtained.

[0009] Furthermore, the fine-grained carbonaceous reducing agent has a particle size of 0.074 mm to 0.5 mm, the medium-grained carbonaceous reducing agent has a particle size of 0.5 mm to 3 mm, and the coarse-grained carbonaceous reducing agent has a particle size of 3 mm to 10 mm.

[0010] Furthermore, the carbonaceous reducing agent is selected from any two or more of anthracite, semi-coke, coke, semi-coke, or coking dust.

[0011] Furthermore, the fine-grained carbonaceous reducing agent is selected from coking dust and semi-coke, the medium-grained carbonaceous reducing agent is selected from anthracite, semi-coke, coke, semi-coke or coking dust, and the coarse-grained carbonaceous reducing agent is selected from anthracite, coke and semi-coke.

[0012] Furthermore, the total amount of carbonaceous reducing agent added is 90%-120% of the theoretical carbon consumption based on fixed carbon, and the fine-grained, medium-grained, and coarse-grained carbonaceous reducing agents account for 20%-35%, 35%-60%, and 20%-35% of the total amount of carbonaceous reducing agent added, respectively, by mass percentage.

[0013] Furthermore, the reaction temperature for adding fine-particle carbonaceous reducing agent is 1350℃ and the reaction time is 30 min; the reaction temperature for adding medium-particle carbonaceous reducing agent is 1500℃-1600℃ and the reaction time is 60 min; and the reaction temperature for adding coarse-particle carbonaceous reducing agent is 1500℃-1550℃ and the reaction time is 30 min.

[0014] Furthermore, the fine-grained carbonaceous reducing agent is added to the upper part of the center of the molten pool during the early stage or initial stage of melting of the high-titanium slag; the medium-grained carbonaceous reducing agent is continuously added or added in batches to the area above the gas blowing zone of the molten pool after the main body of the high-titanium slag has melted; and the coarse-grained carbonaceous reducing agent is intermittently added to the thicker area of ​​the foam slag layer when foam slag appears or during the middle and late stages of the reaction.

[0015] Furthermore, the inert gas is argon and / or helium. The inert gas is introduced into the molten pool through an insert-type injection pipe. The inert gas is stirred until a circulating flow is formed in the molten pool, which promotes the dispersion of reactants and does not cause large-area exposure and violent turbulence on the surface of the molten pool. The inert gas flow rate is reduced or injection is stopped before slag discharge or end-point heat preservation.

[0016] Furthermore, when the high-titanium slag and carbonaceous reducing agent react in an induction furnace, the alternating electromagnetic field generated by the induction coil is used to perform induction synergistic heating on the high-titanium slag molten pool.

[0017] Furthermore, the carbonaceous reducing agent is added to the molten pool through the top charging port of the furnace, and the feeding position of the medium-sized carbonaceous reducing agent is staggered from or partially overlaps with the inert gas blowing zone, while the coarse-sized carbonaceous reducing agent is added at a fixed point in the area with obvious foam slag.

[0018] This invention provides a method for improving the viscosity and flow characteristics of high-titanium slag during carbonization and increasing the carbonization rate. The method uses induction furnace heating, and the induction-assisted heating can be combined with the particle size classification feeding method to reduce local overheating and local viscous zones in the molten pool, enhance the uniformity of the main carbonization reaction in the middle stage, and improve the slag surface recovery ability in the later stage of coarse particle action.

[0019] Furthermore, this invention provides a method for improving the viscosity and flow characteristics of high-titanium slag during carbonization and increasing the carbonization rate. By rapidly initiating the reaction with fine-grained carbonaceous reducing agents in the early stages, the time required for the high-titanium slag to enter an effective reduction state can be shortened. Medium-grained carbonaceous reducing agents, acting as the main reducing gradation, can improve the carbonization rate and reduction efficiency in the middle stage of the reaction. Coarse-grained carbonaceous reducing agents continuously supply carbon and disturb the foamy slag layer in the middle and later stages, weakening the stability of the foamy slag and improving the flow state of the molten pool. Moreover, this invention improves the utilization efficiency of various carbonaceous reducing agents and enhances process adaptability by adapting the original properties of different carbonaceous reducing agents to different particle sizes and staged feeding methods.

[0020] Meanwhile, this invention provides a method for improving the viscosity and flow characteristics of high-titanium slag during carbonization and increasing the carbonization rate. In the mid-to-late stages of the reaction, the application of inert gas stirring enhances molten pool mixing, uniforms temperature and composition, and promotes liquid-solid mass transfer and the escape of reactant gases. When using an induction furnace for heating, the synergistic heating effect formed by electromagnetic induction helps improve the uniformity of molten pool temperature rise, reduces local overheating and local viscous zones, thereby further improving the viscosity and flow characteristics and reaction stability of high-titanium slag. The graded particle size distribution, the synergistic effect of inert gas stirring and induction heating help reduce melt thickening, flyaway losses, and material layer instability caused by excessively rapid local reduction. Through synergistic optimization of the total amount of reducing agent input, particle size distribution, and feeding stage, ineffective carbon consumption and local excessive carbon addition can be reduced, improving the utilization efficiency of carbonaceous reducing agents. While ensuring the advancement of the carbonization reaction, the carbon consumption per unit product is reduced, which is conducive to reducing carbon emission intensity. The improvement of the viscosity and flow characteristics of high-titanium slag and the increase in the carbonization rate can be achieved without relying on a high proportion of flux modification.

[0021] Therefore, the present invention provides a method for improving the viscosity and flow characteristics of high-titanium slag carbonization process and increasing the carbonization rate, which can significantly improve the fluidity of the molten pool, promote the orderly reduction of titanium oxides, increase the carbonization rate, and ensure the smooth progress of the high-titanium slag carbonization process. Attached Figure Description

[0022] Figure 1 A flowchart of a method for improving the viscosity and flow characteristics and increasing the carbonization rate of high-titanium slag carbonization process provided in an embodiment of the present invention; Figure 2 To compare the TiC content and carbonization rate of the carbonized slag obtained under different carbonaceous reducing agent particle size ratios in the method for improving the viscosity and flow characteristics of high-titanium slag carbonization process and increasing the carbonization rate provided in Examples 1-4 of the present invention; Figure 3 To compare the TiC content and carbonization rate of the carbonized slag obtained under different total amounts of carbonaceous reducing agent in the methods for improving the viscosity and flow characteristics of high-titanium slag carbonization process and increasing the carbonization rate provided in Examples 5-8 of the present invention, this study aims to provide a comparative example. Detailed Implementation

[0023] The carbothermic reduction of high-titanium slag is typically accompanied by complex multiphase reactions, coupled mass and heat transfer, and evolution of melt properties. The core challenge lies in the fact that as titanium oxides gradually transform into lower-valence titanium oxides and high-melting-point titanium-containing phases such as titanium carbide, dispersed high-melting-point solid particles easily form in the melt. This leads to increased apparent viscosity of the slag, decreased fluidity, obstructed bubble rise, and enhanced stability of the foamy slag layer. These phenomena not only weaken the mass and heat transfer efficiency within the molten pool but also reduce the reaction interface renewal rate, resulting in both excessively rapid local reduction and uneven overall reaction. Ultimately, this manifests as limited progress in the carbonization reaction, insufficient final carbonization rate, and increased furnace condition fluctuations.

[0024] Furthermore, existing high-titanium slag carbothermic reduction processes often employ a single-particle-size or coarse-batch addition strategy for the reducing agent, making it difficult to simultaneously address the needs for rapid initiation in the initial stage of the reaction, efficient mass transfer in the middle stage, and suppression of foamy slag in the later stage. While fine-particle carbonaceous reducing agents are beneficial for improving initial reaction activity, excessive use can easily lead to violent local reactions, pulverization, and thickening of the molten pool. Coarse-particle carbonaceous reducing agents, although they can prolong carbon supply time and improve the material layer structure, can easily lead to slow reaction initiation and insufficient interfacial contact when used alone. Without reasonable molten pool disturbance measures, this can further exacerbate bubble retention, slag surface fluctuations, and foamy slag accumulation. Therefore, how to achieve functional division and timing matching of carbonaceous reducing agents of different particle sizes during the reduction and carbonization process of high-titanium slag, and enhance interfacial mass transfer, promote the escape of reactive gases, and weaken the stability of foamy slag through appropriate molten pool stirring, thereby improving melt viscosity characteristics, increasing carbonization rate, and maintaining reaction process stability while ensuring reaction rate, has become a key technical problem that urgently needs to be solved in this field.

[0025] Therefore, this invention proposes a new method for reducing and carbonizing high-titanium slag. Without deviating from the existing furnace type and thermal regime, this method improves the viscosity and flow characteristics of high-titanium slag melt and increases the carbonization rate by classifying and adding carbonaceous reducing agents in stages and reasonably interspersing inert gas stirring.

[0026] See Figure 1 The present invention provides a method for improving the viscosity and flow characteristics and increasing the carbonization rate of high-titanium slag during the carbonization process, comprising the following steps: S1: The carbonaceous reducing agent is classified by particle size to obtain fine, medium and coarse particles.

[0027] The fine-grained carbonaceous reducing agent has a particle size of 0.074 mm to 0.5 mm, the medium-grained carbonaceous reducing agent has a particle size of 0.5 mm to 3 mm, and the coarse-grained carbonaceous reducing agent has a particle size of 3 mm to 10 mm.

[0028] The carbonaceous reducing agent is selected from two or more of anthracite, semi-coke, coke, petroleum coke, semi-coke, or coking dust.

[0029] In one specific embodiment of the present invention, carbonaceous reducing agents of different particle sizes are selected based on the original particle size, fixed carbon, volatile matter, reactivity, and high-temperature strength of the raw materials. Among them, coking dust and some semi-coke, due to their finer original particle size and faster reaction, can be used as fine-particle or medium-particle carbonaceous reducing agents. Anthracite, coke, and semi-coke, due to their higher fixed carbon, lower volatile matter, and better high-temperature strength, can be used as medium-particle and coarse-particle carbonaceous reducing agents.

[0030] S2: After placing the high-titanium slag in an induction furnace and heating it to a molten state, fine-grained carbonaceous reducing agent is added to cause the high-titanium slag to undergo preliminary reduction.

[0031] An induction furnace is used as the heating equipment. The alternating electromagnetic field generated by the induction coil is used to perform induction synergistic heating on the high titanium slag molten pool. A relatively low temperature zone in the upper layer and a relatively high temperature zone in the lower layer are formed in the height direction of the molten pool, and an internal circulation flow is formed under the electromagnetic action.

[0032] Among them, the fine-grained carbonaceous reducing agent is added to the upper part of the center of the molten pool through the top charging port of the furnace in the early stage or early stage of the high-titanium slag melting, that is, added to the relatively low temperature zone of the upper layer of the molten pool.

[0033] The initial reaction temperature for adding fine-grained carbonaceous reducing agent to molten high-titanium slag was 1350℃, and the reaction time was 30 min.

[0034] This invention provides a method for improving the viscosity and flow characteristics of high-titanium slag during carbonization and increasing the carbonization rate. The method uses induction furnace heating, and the induction-assisted heating can be combined with the particle size classification feeding method to reduce local overheating and local viscous zones in the molten pool, enhance the uniformity of the main carbonization reaction in the middle stage, and improve the slag surface recovery ability in the later stage of coarse particle action.

[0035] S3: Then add medium-sized carbonaceous reducing agent and spray inert gas above the molten pool to enhance liquid-solid contact, promote mass and heat transfer, and accelerate the carbothermic reduction and carbonization reaction of titanium oxides in high-titanium slag.

[0036] Among them, the medium-sized carbonaceous reducing agent is continuously added or added in batches to the main circulation zone in the lower part of the molten pool above the gas blowing zone after the initial reaction of the high-titanium slag.

[0037] The reaction temperature of the medium-sized carbonaceous reducing agent with the high-titanium slag is 1500℃-1600℃, and the reaction time is 60min.

[0038] In this process, inert gas is introduced into the molten pool through an insert-type blow pipe, and when inert gas is blown above the molten pool, the flow rate of the inert gas blown by the blow gun is controlled at 8L / min - 15L / min.

[0039] The medium-sized carbonaceous reducing agent is added to the molten pool through the charging port on the top of the induction furnace. Moreover, the charging position of the medium-sized carbonaceous reducing agent is staggered from or partially overlaps with the inert gas blowing zone.

[0040] The stirring intensity of the inert gas should be such that it forms a circulating flow in the molten pool, promotes the dispersion of reactants, and does not cause large-area exposure or violent turbulence on the surface of the molten pool.

[0041] S4: Add coarse-grained carbonaceous reducing agent in the later stage of the reaction, and intermittently spray inert gas above the molten pool. This allows the coarse-grained carbonaceous reducing agent to continuously supply carbon while mechanically disturbing the foam slag layer, weakening the foam stability and promoting gas escape.

[0042] The coarse-grained carbonaceous reducing agent is intermittently added to the molten pool when foamy slag appears or in the middle and late stages of the reaction. In particular, the coarse-grained carbonaceous reducing agent is preferably added at specific points to the bulging area of ​​the high-titanium slag surface, the area with obvious foamy slag, and the corresponding high-temperature reaction zone below it.

[0043] The reaction temperature for adding coarse-grained carbonaceous reducing agent is 1500℃-1550℃, and the reaction time is 30 minutes.

[0044] In this process, inert gas is introduced into the molten pool through an insertion-type spray pipe, and when the inert gas is intermittently sprayed above the molten pool, the spray flow rate of the spray gun is controlled at 12L / min-18L / min.

[0045] The coarse-grained carbonaceous reducing agent is added to the molten pool through the charging port at the top of the induction furnace, and the coarse-grained carbonaceous reducing agent is added at a specific point to the area with obvious foamy slag.

[0046] In the entire reaction process, the total amount of carbonaceous reducing agent of fine, medium and coarse particle sizes added is 90%-120% of the theoretical reduced carbon consumption mass, based on fixed carbon.

[0047] Furthermore, the fine-grained, medium-grained, and coarse-grained carbonaceous reducing agents account for 20%-35%, 35%-60%, and 20%-35% of the total carbonaceous reducing agent content, respectively, by mass percentage.

[0048] This invention provides a method to improve the viscosity and flow characteristics of high-titanium slag during carbonization and increase the carbonization rate. By rapidly initiating the reaction with fine-grained carbonaceous reducing agents in the early stages, the time required for the high-titanium slag to enter an effective reduction state can be shortened. Medium-grained carbonaceous reducing agents, acting as the main reducing gradation, can improve the carbonization rate and reduction efficiency in the middle stages of the reaction. Coarse-grained carbonaceous reducing agents continuously supply carbon and disturb the foamy slag layer in the middle and later stages, weakening the stability of the foamy slag and improving the flow state of the molten pool. Furthermore, this invention improves the utilization efficiency of various carbonaceous reducing agents and enhances process adaptability by adapting the original properties of different carbonaceous reducing agents to different particle sizes and staged feeding methods.

[0049] S5: After the heat preservation reaction is completed, stop blowing inert gas to allow the molten pool to return to stable stratification and obtain high titanium slag carbonization products with improved viscosity and flow characteristics and increased carbonization rate.

[0050] In particular, reducing the flow rate of inert gas or stopping the blowing before slag discharge or end-point heat preservation can promote the separation of the slag phase and reaction products in the molten pool.

[0051] This invention provides a method for improving the viscosity characteristics and increasing the carbonization rate of high-titanium slag during the carbonization process. The method utilizes the alternating electromagnetic field generated by the induction coil of the induction furnace to perform induction synergistic heating on the high-titanium slag molten pool, making the temperature field of the molten pool more uniform. This method works in conjunction with the inert gas enhanced blowing in the medium-particle stage and the pulse blowing in the coarse-particle stage to promote liquid-solid mass transfer, reduce local overheating, and increase the final carbonization rate.

[0052] Furthermore, the present invention provides a method for improving the viscosity and flow characteristics of high-titanium slag during carbonization and increasing the carbonization rate. In the mid-to-late stage of the reaction, the application of inert gas stirring can enhance the mixing of the molten pool, uniform temperature and composition, and promote liquid-solid mass transfer and the escape of reactant gases. When an induction furnace is used for heating, the synergistic heating effect formed by electromagnetic induction helps to improve the uniformity of molten pool temperature rise, reduce local overheating and local viscous zones, thereby further improving the viscosity and flow characteristics and reaction stability of high-titanium slag. The graded distribution of particle size, the synergistic effect of inert gas stirring and induction heating helps to reduce the problems of melt thickening, fly-away loss and material layer instability caused by localized excessively rapid reduction. Through the synergistic optimization of the total amount of reducing agent input, particle size distribution and feeding stage, ineffective carbon consumption and localized excessive carbon addition can be reduced, and the utilization efficiency of carbonaceous reducing agents can be improved. While ensuring the advancement of the carbonization reaction, the carbon consumption per unit product is reduced, which is conducive to reducing carbon emission intensity. The improvement of viscosity and flow characteristics and the increase of carbonization rate of high-titanium slag can be achieved without relying on high proportion of flux modification.

[0053] Comparative Example High-titanium slag is added to an induction furnace and heated to 1350℃. Then, all the carbonaceous reducing agent is added to the molten pool at once for a reduction reaction. The carbonaceous reducing agent is a mixture of anthracite and coking dust, but without fine, medium, and coarse particle size classification; instead, a mixed particle size of 0.074mm-10mm is used directly. After the slag phase has completely melted, the temperature is further increased to 1600℃ and held for 120 minutes. No inert gas is introduced for stirring the molten pool during the entire reaction. After the reaction, the mixture is cooled by water quenching to obtain the carbonized product.

[0054] The composition of the high-titanium slag used in the comparative example of this invention is shown in Table 1.

[0055] Table 1. Main component indicators of high-titanium slag / wt.%

[0056] The method provided in this comparative example yields the following results regarding the TiC content and carbonization rate in the carbonized slag: Figure 2 or Figure 3 As shown.

[0057] Example 1 In this example, the same high-titanium slag as the comparative example was selected. A carbonaceous reducing agent was added at 110% of the theoretical fixed carbon consumption. The carbonaceous reducing agent consisted primarily of anthracite and coking dust in a 6:4 mass ratio. Fine particles were obtained from coking dust, medium particles from a mixture of anthracite and coking dust, and coarse particles from anthracite. The particles were then sieved to obtain the following particle sizes: fine: 0.074mm-0.5mm; medium: 0.5mm-3mm; coarse: 3mm-10mm. The carbonaceous reducing agent was added at 110% of the theoretical fixed carbon consumption, with the three particle sizes prepared in a mass ratio of 35:45:20.

[0058] High-titanium slag was placed in an induction furnace and heated to 1350℃. 70% of the total fine-particle-grade reducing agent was added, and the mixture was held at this temperature for 20 minutes. The remaining 30% of the fine-particle-grade carbonaceous reducing agent was then added, and the reaction was allowed to proceed for 10 minutes. The temperature was then raised to 1600℃, and medium-particle-grade carbonaceous reducing agent was added in four portions over 60 minutes, each portion accounting for 25% of the total medium-particle-grade reducing agent. The argon flow rate was increased to 12 L / min, and the reaction was continued for 60 minutes. When a foamy slag layer appeared, coarse-particle-grade carbonaceous reducing agent was added in two portions, each portion accounting for 50% of the total coarse-particle-grade reducing agent. Simultaneous pulsed argon stirring was used; the continuous blowing flow rate was 18 L / min, and the reaction was allowed to proceed for 30 minutes. After the reaction, the mixture was cooled by water quenching to obtain the carbonized product.

[0059] In the method for improving the viscosity and flow characteristics and increasing the carbonization rate of high-titanium slag provided in Example 1 of this invention, the TiC content and carbonization rate of the carbonaceous reducing agent obtained when the particle size distribution ratio is 35:45:20 are as follows: Figure 2 As shown.

[0060] Example 2 The example uses the same high-titanium slag as the comparative example. The carbonaceous reducing agent is generally composed of anthracite and coking dust in a mass ratio of 6:4. The fine particle size uses coking dust, the medium particle size uses a mixture of anthracite and coking dust particles, and the coarse particle size uses anthracite particles. The carbonaceous reducing agent is added at 110% of the fixed theoretical carbon consumption. The mass ratio of the fine particle size (0.074mm-0.5mm), the medium particle size (0.5mm-3mm), and the coarse particle size (3mm-10mm) is 20:45:35.

[0061] High-titanium slag was placed in an induction furnace and heated to 1350℃. 70% of the total fine-particle carbonaceous reducing agent was added, and the mixture was held at this temperature for 20 minutes. The remaining 30% of the fine-particle carbonaceous reducing agent was then added, and the reaction was allowed to proceed for 10 minutes. The temperature was then raised to 1600℃, and medium-particle carbonaceous reducing agent was added in four portions over 60 minutes, each portion accounting for 25% of the total medium-particle carbonaceous reducing agent, while simultaneously increasing the argon flow rate to 12 L / min. After a foamy slag layer appeared, coarse-particle carbonaceous reducing agent was added in two portions, using low-frequency pulsed argon stirring with a peak injection flow rate of 18 L / min and a pulse period of 20 seconds. The reaction was then held at this temperature for 30 minutes. After the reaction was completed, the mixture was cooled by water quenching to obtain the carbonized product.

[0062] In the method for improving the viscosity and flow characteristics and increasing the carbonization rate of high-titanium slag provided in Example 2 of this invention, the TiC content and carbonization rate of the carbonaceous reducing agent obtained when the particle size distribution ratio is 20:45:35 are as follows: Figure 2 As shown.

[0063] Example 3 The example uses the same high-titanium slag as the comparative example. The carbonaceous reducing agent is generally composed of anthracite and coking dust in a mass ratio of 6:4. The fine particle size uses coking dust, the medium particle size uses a mixture of anthracite and coking dust particles, and the coarse particle size uses anthracite particles. The carbonaceous reducing agent is added at 110% of the fixed theoretical carbon consumption. The mass ratio of the fine particle size (0.074mm-0.5mm), the medium particle size (0.5mm-3mm), and the coarse particle size (3mm-10mm) is 20:60:20.

[0064] High-titanium slag was placed in an induction furnace and heated to 1350℃. 70% of the total fine-particle size was added, and the mixture was held at this temperature for 20 minutes. The remaining 30% of the fine-particle carbonaceous reducing agent was then added, and the reaction was allowed to proceed for 10 minutes. Subsequently, the temperature was raised to 1600℃, and medium-particle carbonaceous reducing agent was added in four portions over 60 minutes, each time at 25% of the total amount, while increasing the argon flow rate to 9-13 L / min. In the later stages of the reaction, coarse-particle reducing agent was added in two portions, each time at 50% of the total amount, and the reaction was allowed to proceed for 30 minutes. After the reaction was complete, the mixture was cooled by water quenching to obtain the carbonized product.

[0065] In the method for improving the viscosity and flow characteristics and increasing the carbonization rate of high-titanium slag provided in Example 3 of this invention, the TiC content and carbonization rate of the carbonaceous reducing agent obtained when the particle size distribution ratio is 20:60:20 are as follows: Figure 2 As shown.

[0066] Example 4 The example uses the same high-titanium slag as the comparative example. The carbonaceous reducing agent is composed of anthracite and coking dust in a mass ratio of 6:4. The fine particles are coking dust, the medium particles are a mixture of anthracite and coking dust, and the coarse particles are anthracite particles. The carbonaceous reducing agent is added at 110% of the fixed theoretical carbon consumption. The fine particles are 0.074mm-0.5mm, the medium particles are 0.5mm-3mm, and the coarse particles are 3mm-10mm, with a mass ratio of 25:50:25.

[0067] High-titanium slag was placed in an induction furnace and heated to 1350℃. 70% of the total fine-particle-grade reducing agent was added, and the mixture was held at this temperature for 20 minutes. The remaining 30% of the fine-particle-grade carbonaceous reducing agent was then added, and the reaction was allowed to proceed for 10 minutes. The temperature was then raised to 1600℃, and medium-particle-grade carbonaceous reducing agent was added in four portions over 60 minutes, with the argon flow rate increased to 12 L / min. The reaction was continued for another 60 minutes. Later in the reaction, coarse-particle-grade carbonaceous reducing agent was added in two portions, each time amounting to 50% of the total coarse-particle-grade reducing agent, simultaneously using pulsed argon gas injection at a peak flow rate of 18 L / min, and the reaction was allowed to proceed for 30 minutes. After the reaction, the mixture was cooled by water quenching to obtain the carbonized product.

[0068] In the method for improving the viscosity and flow characteristics and increasing the carbonization rate of high-titanium slag provided in Example 4 of this invention, the TiC content and carbonization rate of the carbonaceous reducing agent obtained when the particle size distribution ratio is 25:50:25 are as follows: Figure 2 As shown.

[0069] pass Figure 2 The comparison shows that when the particle size distribution ratios in Examples 1-4 of the present invention are 5:45:20; 20:45:35; 20:60:20; and 25:50:25, respectively, as the fine particle size decreases from a relatively high level to a moderate level, the medium particle size increases and becomes dominant, and the coarse particle size maintains an appropriate amount of auxiliary particles, the three processes of "initial reaction - mid-term main carbonization - late-term stable pool carbon supply" in the molten pool are matched and strengthened, which can improve the carbonization rate.

[0070] Example 5 The example uses the same high-titanium slag as the comparative example. The carbonaceous reducing agent is generally composed of anthracite and coking dust in a mass ratio of 6:4. The fine particle size uses coking dust, the medium particle size uses a mixture of anthracite and coking dust particles, and the coarse particle size uses anthracite particles. The carbonaceous reducing agent is added at 90% of the fixed theoretical carbon consumption. The mass ratio of the fine particle size (0.074mm-0.5mm), the medium particle size (0.5mm-3mm), and the coarse particle size (3mm-10mm) is adjusted to 25:50:25.

[0071] High-titanium slag was placed in an induction furnace and heated to 1350℃. 70% of the total fine-particle-grade reducing agent was added, and the mixture was held at this temperature for 20 minutes. The remaining 30% of the fine-particle-grade carbonaceous reducing agent was then added, and the reaction was allowed to proceed for 10 minutes. Subsequently, the temperature was raised to 1600℃, and medium-particle-grade carbonaceous reducing agent was continuously added over 60 minutes, while the argon flow rate was increased to 12 L / min to continuously intensify the reaction for another 60 minutes. In the later stages of the reaction, coarse-particle-grade carbonaceous reducing agent was added in two portions, each time amounting to 50% of the total coarse-particle-grade reducing agent, using intermittent argon gas injection with a peak flow rate of 18 L / min, and the reaction was allowed to proceed for 30 minutes. After the reaction was completed, the mixture was cooled by water quenching to obtain the carbonized product.

[0072] During the experiment, it can be observed that: after the addition of fine particles, although a black and shiny reaction zone gradually forms on the surface of the molten pool, the expansion rate of the reaction zone is relatively slow, and the disappearance of local viscous zones is not sufficient; after entering the stage of enhanced stirring of medium particles, although the molten pool forms a certain circulation, the surface turbulence is not continuous enough, and local stagnant zones still exist; after entering the stage of fixed-point addition of coarse particles, although the foam slag layer can be locally weakened, the decay rate is slow, and several bulging areas can still be seen on the surface.

[0073] In the method for improving the viscosity and flow characteristics and increasing the carbonization rate of high-titanium slag provided in Example 5 of this invention, the TiC content and carbonization rate in the carbonized slag obtained when the total amount of carbonaceous reducing agent added is 90% of the fixed theoretical carbon consumption are as follows: Figure 3 As shown.

[0074] Example 6 The example uses the same high-titanium slag as the comparative example. The carbonaceous reducing agent is composed of anthracite and coking dust in a mass ratio of 6:4. The fine particle size uses coking dust, the medium particle size uses a mixture of anthracite and coking dust particles, and the coarse particle size uses anthracite particles. The carbonaceous reducing agent is added at 100% of the fixed theoretical carbon consumption. The mass ratio of the fine particle size (0.074mm-0.5mm), the medium particle size (0.5mm-3mm), and the coarse particle size (3mm-10mm) is adjusted to 25:50:25.

[0075] High-titanium slag was placed in an induction furnace and heated to 1350℃. 70% of the total fine-particle-grade reducing agent was added, and the mixture was held at this temperature for 20 minutes. The remaining 30% of the fine-particle-grade carbonaceous reducing agent was then added, and the reaction was allowed to proceed for 10 minutes. Subsequently, the temperature was raised to 1600℃, and medium-particle-grade carbonaceous reducing agent was continuously added over 60 minutes, while the argon flow rate was increased to 12 L / min to continuously intensify the reaction for another 60 minutes. In the later stages of the reaction, coarse-particle-grade carbonaceous reducing agent was added in two portions, each time amounting to 50% of the total coarse-particle-grade reducing agent, using intermittent argon gas injection with a peak flow rate of 18 L / min, and the reaction was allowed to proceed for 30 minutes. After the reaction was completed, the mixture was cooled by water quenching to obtain the carbonized product.

[0076] During the experiment, it was observed that: after the addition of fine particles, a relatively continuous reaction layer was formed on the surface of the molten pool relatively quickly, and the distribution of the black and shiny areas was relatively uniform; after entering the stage of enhanced stirring of medium particles, the overall stirring of the molten pool tended to be uniform, and the local crusting, enrichment of unreacted carbon, and differences in surface brightness were reduced; after the fixed-point addition of coarse particles, the foam slag layer gradually changed from continuous expansion to local intermittent undulation, and the slag surface fluctuation remained within a relatively stable range.

[0077] In the method for improving the viscosity and flow characteristics and increasing the carbonization rate of high-titanium slag provided in Example 6 of this invention, the TiC content and carbonization rate in the carbonized slag obtained when the total amount of carbonaceous reducing agent added is 100% of the fixed theoretical carbon consumption are as follows: Figure 3 As shown.

[0078] Example 7 The example uses the same high-titanium slag as the comparative example. The carbonaceous reducing agent is generally composed of anthracite and coking dust in a mass ratio of 6:4. The fine particle size uses coking dust, the medium particle size uses a mixture of anthracite and coking dust particles, and the coarse particle size uses anthracite particles. The carbonaceous reducing agent is added at 110% of the fixed theoretical carbon consumption. The mass ratio of the fine particle size (0.074mm-0.5mm), the medium particle size (0.5mm-3mm), and the coarse particle size (3mm-10mm) is adjusted to 25:50:25.

[0079] High-titanium slag was placed in an induction furnace and heated to 1350℃. 70% of the total fine-particle-grade reducing agent was added, and the mixture was held at this temperature for 20 minutes. The remaining 30% of the fine-particle-grade carbonaceous reducing agent was then added, and the reaction was allowed to proceed for 10 minutes. Subsequently, the temperature was raised to 1600℃, and medium-particle-grade carbonaceous reducing agent was continuously added over 60 minutes, while the argon flow rate was increased to 12 L / min to continuously intensify the reaction for another 60 minutes. In the later stages of the reaction, coarse-particle-grade carbonaceous reducing agent was added in two portions, each time amounting to 50% of the total coarse-particle-grade reducing agent, using intermittent argon gas injection with a peak flow rate of 18 L / min, and the reaction was allowed to proceed for 30 minutes. After the reaction was completed, the mixture was cooled by water quenching to obtain the carbonized product.

[0080] During the experiment, it was observed that: after the addition of fine particles, the initial reaction interface was established quickly, and the black and shiny reaction zone on the surface expanded in a short time; after entering the stage of enhanced stirring of medium particles, the internal circulation of the molten pool was significantly enhanced, the surface color and flow state were more uniform, and the local stagnation and crusting phenomena were further reduced; after entering the stage of fixed-point addition and pulse jetting of coarse particles, the foam slag layer decayed quickly, the number of bubbles retained on the surface decreased, and the continuity of slag flow was better.

[0081] In the method for improving the viscosity and flow characteristics and increasing the carbonization rate of high-titanium slag provided in Example 7 of this invention, the TiC content and carbonization rate in the carbonized slag obtained when the total amount of carbonaceous reducing agent added is 110% of the fixed theoretical carbon consumption are as follows: Figure 3 As shown.

[0082] Example 8 The example uses the same high-titanium slag as the comparative example. The carbonaceous reducing agent is generally composed of anthracite and coking dust in a mass ratio of 6:4. The fine particle size uses coking dust, the medium particle size uses a mixture of anthracite and coking dust particles, and the coarse particle size uses anthracite particles. The carbonaceous reducing agent is added at 120% of the fixed theoretical carbon consumption. The mass ratio of the fine particle size (0.074mm-0.5mm), the medium particle size (0.5mm-3mm), and the coarse particle size (3mm-10mm) is adjusted to 25:50:25.

[0083] High-titanium slag was placed in an induction furnace and heated to 1350℃. 70% of the total fine-particle-grade reducing agent was added, and the mixture was held at this temperature for 20 minutes. The remaining 30% of the fine-particle-grade carbonaceous reducing agent was then added, and the reaction was allowed to proceed for 10 minutes. Subsequently, the temperature was raised to 1600℃, and medium-particle-grade carbonaceous reducing agent was continuously added over 60 minutes, while the argon flow rate was increased to 12 L / min to continuously intensify the reaction for another 60 minutes. In the later stages of the reaction, coarse-particle-grade carbonaceous reducing agent was added in two portions, each time amounting to 50% of the total coarse-particle-grade reducing agent, using intermittent argon gas injection with a peak flow rate of 18 L / min, and the reaction was allowed to proceed for 30 minutes. After the reaction was completed, the mixture was cooled by water quenching to obtain the carbonized product.

[0084] During the experiment, it was observed that: after the addition of fine particles, the initial reaction was established relatively quickly; after entering the stage of enhanced stirring of medium particles, the molten pool churned more strongly, the frequency of surface bubbling increased significantly, and the local carbonaceous particle enrichment area was more likely to form a short-term high reaction zone; after entering the stage of fixed-point addition of coarse particles and pulse injection, although the foam slag layer could still be weakened, the slag surface fluctuation was more obvious than in Experiment 7, and the local surface churning and flue gas fluctuation were enhanced.

[0085] In the method for improving the viscosity and flow characteristics and increasing the carbonization rate of high-titanium slag provided in Example 8 of this invention, the TiC content and carbonization rate in the carbonized slag obtained when the total amount of carbonaceous reducing agent added is 120% of the fixed theoretical carbon consumption are as follows: Figure 3 As shown.

[0086] pass Figure 3 The comparison shows that when the total amount of carbonaceous reducing agent added in Examples 5-8 of the present invention is 90%, 100%, 110%, and 120% of the theoretical carbon consumption, respectively, the carbonization rate increases with the increase of the amount added. However, the excessive amount of carbon added affects the reaction rate of the molten pool, resulting in excessive TiC generation, which leads to viscous slag and severe foam slag overflow, thus causing instability of the molten pool reaction system and a decrease in the carbonization rate.

[0087] As can be seen from the above comparative examples and Examples 1-8 of the present invention, the method provided by the present invention for improving the viscosity and flow characteristics of high titanium slag carbonization process and increasing carbonization rate can establish the initial reaction interface through fine particles, strengthen the main carbonization reaction through medium particles, weaken the stability of foam slag through coarse particles, and work synergistically with the inert gas injection in the medium and coarse particle stages to achieve the control of the physical properties of the high titanium slag molten pool and the optimization of the reaction process.

[0088] Therefore, this invention provides a method for improving the viscous flow characteristics and increasing the carbonization rate of high-titanium slag during carbonization. This method adapts the original particle size, fixed carbon, volatile matter, reactivity, and mechanical strength of the carbonaceous reducing agent to different particle sizes and staged feeding methods. This allows different carbon sources to play different roles in the high-titanium slag reduction and carbonization process, respectively in the early reaction stage, the middle stage of main reduction, and the later stage of continuous carbon supply and foam stabilization. Furthermore, when the total input ratio of the carbonaceous reducing agent is controlled at 100%-110% of the theoretical fixed carbon consumption, and the mass ratio of fine, medium, and coarse particles is controlled at approximately 25:50:25, a better overall effect can be achieved. If more emphasis is placed on suppressing foamy slag and improving slag fluidity, the proportion of coarse particles can be appropriately increased to about 35%. The results of the above embodiments further demonstrate that the method of this invention has good process applicability and promotional value in improving the viscous flow characteristics and increasing the carbonization rate of high-titanium slag.

[0089] As shown above, the method provided by the present invention for improving the viscosity and flow characteristics of high-titanium slag during carbonization and increasing the carbonization rate can simultaneously improve the viscosity and flow characteristics of high-titanium slag and increase the carbonization rate by establishing the initial reaction interface with fine particles, strengthening the main carbonization reaction with medium particles, weakening the stability of foam slag with coarse particles, and coordinating with staged inert gas stirring.

[0090] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the protection scope of the present invention.

Claims

1. A method for improving the viscous flow properties and increasing the carbonation rate of high titanium slag carbonation process, characterized in that, Includes the following steps: Carbonaceous reducing agents were classified by particle size to obtain three particle sizes: fine, medium, and coarse. After heating the high-titanium slag to a molten state in an induction furnace, a fine-grained carbonaceous reducing agent is added for initial reaction. Then add medium-sized carbonaceous reducing agent to react, and continuously spray inert gas above the molten pool; Finally, coarse-grained carbonaceous reducing agent is added to react, and inert gas is intermittently injected above the molten pool; After the reaction is completed, a high-titanium slag carbonization product with improved viscosity and increased carbonization rate is obtained.

2. The method of claim 1, wherein, The fine-grained carbonaceous reducing agent has a particle size of 0.074 mm to 0.5 mm, the medium-grained carbonaceous reducing agent has a particle size of 0.5 mm to 3 mm, and the coarse-grained carbonaceous reducing agent has a particle size of 3 mm to 10 mm.

3. The method of claim 2, wherein, The carbonaceous reducing agent is selected from two or more of anthracite, semi-coke, coke, semi-coke, or coking dust.

4. The method of claim 3, wherein, The fine-grained carbonaceous reducing agent is selected from coking dust and semi-coke; the medium-grained carbonaceous reducing agent is selected from anthracite, semi-coke, coke, semi-coke or coking dust; and the coarse-grained carbonaceous reducing agent is selected from anthracite, coke and semi-coke.

5. The method of claim 4, wherein, The total amount of carbonaceous reducing agent added is 90%-120% of the theoretical carbon consumption based on fixed carbon. The fine-grained, medium-grained, and coarse-grained carbonaceous reducing agents account for 20%-35%, 35%-60%, and 20%-35% of the total amount of carbonaceous reducing agent added, respectively, by mass percentage.

6. The method of claim 5, wherein, The initial reaction temperature for adding fine-grained carbonaceous reducing agent is 1350℃, and the reaction time is 30 min. The reaction temperature for adding medium-grained carbonaceous reducing agent is 1500℃-1600℃, and the reaction time is 60 min. The reaction temperature for adding coarse-grained carbonaceous reducing agent is 1500℃-1550℃, and the reaction time is 30 min.

7. The method of claim 6, wherein, The fine-grained carbonaceous reducing agent is added to the upper part of the center of the molten pool during the early stage or initial stage of melting of the high-titanium slag; the medium-grained carbonaceous reducing agent is added continuously or in batches to the area above the gas blowing zone of the molten pool after the main body of the high-titanium slag has melted; the coarse-grained carbonaceous reducing agent is added intermittently to the thicker area of ​​the foamy slag layer when foamy slag appears or during the middle and late stages of the reaction.

8. The method of claim 1, wherein, The inert gas is argon and / or helium. The inert gas is introduced into the molten pool through an insert-type injection pipe. The inert gas is stirred until a circulating flow is formed in the molten pool, which promotes the dispersion of reactants and does not cause large-area exposure and violent turbulence on the surface of the molten pool. The inert gas flow rate is reduced or injection is stopped before slag discharge or end-point heat preservation.

9. The method of claim 1, wherein, When the high-titanium slag and carbonaceous reducing agent react in an induction furnace, the alternating electromagnetic field generated by the induction coil is used to perform induction synergistic heating on the high-titanium slag molten pool.

10. The method of claim 1, wherein, The carbonaceous reducing agent is added to the molten pool through the top charging port of the furnace. The feeding position of the medium-sized carbonaceous reducing agent is staggered from or partially overlaps with the inert gas blowing zone, while the coarse-sized carbonaceous reducing agent is added at a fixed point in the area with obvious foamy slag.

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