A method for improving foaming of carbonization process of high-titanium blast furnace slag
By using a gradient addition of composite additives and carbonaceous reducing agents, the viscosity and foaming problems in the carbonization process of high-titanium blast furnace slag were solved, achieving efficient carbonization reaction and safe smelting, reducing energy consumption and improving economic benefits.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- NORTHEASTERN UNIV CHINA
- Filing Date
- 2026-05-11
- Publication Date
- 2026-06-12
AI Technical Summary
High-titanium blast furnace slag has high viscosity and severe foaming during carbonization, which leads to difficulties in heat and mass transfer and safety hazards. Existing technologies cannot accurately control the reaction process.
A gradient addition method of composite additives and carbonaceous reducing agents is adopted. First, a portion of the carbonaceous reducing agent is added to the crucible. Then, the high-titanium blast furnace slag is mixed with the composite additives and heated. By directionally controlling the reaction process, the early TiC enrichment is suppressed and the TiC particle size is optimized. The remaining carbonaceous reducing agent is added in the later stage to break the bubbles and control the viscosity and foaming of the slag.
It significantly reduces slag viscosity and foaming degree, increases carbonization rate, improves slag fluidity, reduces energy consumption, ensures smooth smelting, and reduces production costs.
Smart Images
Figure CN122189386A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of iron and steel smelting technology, and in particular to a method for improving the foaming process of high-titanium blast furnace slag carbonization. Background Technology
[0002] my country possesses abundant vanadium-titanium magnetite resources, resulting in a large amount of titanium-containing blast furnace slag during blast furnace smelting. When the TiO2 content in the slag is 15%-30%, the extraction and utilization of titanium becomes quite challenging.
[0003] In the carbothermic reduction process of high-titanium blast furnace slag, TiO2 reacts with carbonaceous reducing agents to form titanium carbide (TiC). TiC is a high-melting-point substance (melting point 3140℃) and exists in the slag as solid particles at smelting temperatures, leading to increased slag viscosity. Simultaneously, TiC, as a surface-active substance, significantly reduces the surface tension of the slag, enhancing its adsorption of bubbles. As the carbide reaction proceeds, the formation of a large number of TiC solid particles creates a stable foam layer, hindering the coalescence and rise of CO bubbles, resulting in severe foaming of the slag. This foaming phenomenon not only impedes heat and mass transfer processes, causing incomplete reactions and increased energy consumption, but also easily triggers safety accidents such as splashing, posing significant challenges to safe production.
[0004] Current research mostly involves adding a single flux to regulate the slag system and reduce viscosity, but this makes it difficult to precisely control the reaction process and effectively improve the foaming phenomenon.
[0005] Therefore, in order to address the above problems, there is an urgent need for a reasonable method to improve the foaming process of high-titanium slag carbonization. Summary of the Invention
[0006] The technical problem to be solved by the present invention is to provide a reasonable and effective method to improve the foaming of high titanium blast furnace slag in the carbonization process, and to solve the problems of high viscosity and severe foaming in the smelting process of high titanium blast furnace slag in the prior art, so as to enable the carbonization reaction to proceed smoothly.
[0007] To address the aforementioned technical problems, this invention provides a method for improving foaming during the carbonization process of high-titanium blast furnace slag, comprising the following steps: A portion of the dried carbonaceous reducing agent is added to the first crucible beforehand; The dried high-titanium blast furnace slag was mixed with the composite additive and then placed into the second crucible. The second crucible is placed in a resistance furnace and heated until the high-titanium blast furnace slag melts, then poured into the first crucible. The first crucible is placed in an electric resistance furnace and heated to 1400-1500℃ for carbonization reaction for 1.5-2.5 hours; The resistance furnace is heated to 1550℃-1650℃, and the remaining carbonaceous reducing agent is added to the first crucible for carbonization reaction for 0.2h-1h to obtain carbonized slag. The obtained carbonized slag is rapidly cooled to obtain the carbonized slag product.
[0008] Furthermore, the drying of the carbonaceous reducing agent is carried out in an oven at 100℃-110℃ for 3-5 hours, and the drying of the high-titanium blast furnace slag is carried out in an oven at 100℃-110℃ for 3-5 hours.
[0009] Furthermore, the carbonaceous reducing agent has a fixed carbon content of not less than 75% and an ash content of not more than 20%.
[0010] Furthermore, the mass of the carbonaceous reducing agent pre-added to the first crucible is 7%-9% of the mass of the high-titanium blast furnace slag.
[0011] Furthermore, the composite additive comprises, by mass percentage, 40%-60% fluorite, 15%-25% borides, 10%-20% quicklime, 5%-15% lightly calcined magnesite, and 2%-8% MnO.
[0012] Furthermore, the mass of the composite additive is 2%-6% of the mass of the high-titanium blast furnace slag.
[0013] Furthermore, the second crucible is placed in a resistance furnace and heated to a temperature of 1250℃-1350℃.
[0014] Furthermore, after the first crucible is placed in a resistance furnace and heated to 1400℃-1500℃ for carbonization reaction for 1.5h-2h, 70%-90% of the TiO2 in the high-titanium blast furnace slag is reduced to low-valent titanium oxides.
[0015] Furthermore, the remaining dried carbonaceous reducing agent is added to the first crucible via a charging funnel.
[0016] Furthermore, the mass of the remaining dried carbonaceous reducing agent added to the first crucible is 4%-6% of the mass of the high-titanium blast furnace slag.
[0017] This invention provides a method for improving foaming during the carbonization process of high-titanium blast furnace slag. During smelting, high-titanium blast furnace slag with added composite additives is heated and melted, then poured into a crucible pre-filled with a portion of a carbonaceous reducing agent. The temperature is rapidly increased to initiate a carbonization reaction, reducing TiO2 to low-valent titanium oxides. By directionally controlling the reaction process of the Ti-containing phase, early TiC enrichment can be suppressed at the source, reducing the core inducing factor of foaming. Simultaneously, optimized TiC particle size and efficient preparation are ensured, achieving the goal of reducing slag viscosity and improving foaming. This facilitates the timely removal of CO gas, effectively reducing the degree of foaming. In the later stages of smelting, the remaining carbonaceous reducing agent is added to the crucible, further effectively breaking up bubbles generated by the reaction, creating favorable kinetic conditions, facilitating the timely removal of CO gas, reducing slag viscosity, and inhibiting the formation of foamy slag, thereby effectively improving foaming during the carbonization process of high-titanium blast furnace slag.
[0018] Furthermore, this invention provides a method for improving foaming during the carbonization process of high-titanium blast furnace slag. By adding composite additives to the high-titanium blast furnace slag, synergistic modification of the slag's physicochemical properties is achieved. This not only refines the size of TiC grains produced by carbonization reduction, reduces TiC aggregation, and lowers the apparent viscosity of the slag, effectively improving slag fluidity, but also lowers the melting temperature of the slag system, reducing the reaction temperature to a certain extent, allowing the carbonization reaction to proceed in the forward direction. This is beneficial for increasing the carbonization rate, reducing smelting power consumption, lowering production costs, and improving economic efficiency. Simultaneously, the addition of composite additives can prevent excessive reduction of TiO2 in the early stages, further reducing TiC enrichment, lowering slag viscosity, improving slag fluidity, and improving foaming during the high-titanium blast furnace slag carbonization process.
[0019] Therefore, the present invention provides a method for improving the foaming process of high-titanium blast furnace slag carbonization, which can significantly reduce the viscosity and foaming degree of slag, while increasing the carbonization rate and improving the fluidity of slag, thus enabling the smelting to proceed smoothly. This provides a feasible technical path for the smooth carbonization process of high-titanium blast furnace slag, and can also reduce energy consumption, save production costs, and improve economic benefits, making it worthy of widespread application. Attached Figure Description
[0020] Figure 1 A flowchart of a method for improving foaming during the carbonization process of high-titanium blast furnace slag, provided by an embodiment of the present invention; Figure 2 The microstructure of the carbonized slag obtained by the method provided in the comparative example of this invention is shown in the figure. Figure 3 The image shows the microstructure of the carbonized slag obtained by the method provided in Example 1 of this invention. Figure 4 The image shows the microstructure of the carbonized slag obtained by the method provided in Embodiment 2 of the present invention. Figure 5 The image shows the microstructure of the carbonized slag obtained by the method provided in Example 3 of this invention. Figure 6 The image shows the microstructure of the carbonized slag obtained by the method provided in Example 4 of this invention. Figure 7 The image shows the microstructure of the carbonized slag obtained by the method provided in Example 5 of this invention. Figure 8 The image shows the microstructure of the carbonized slag obtained by the method provided in Example 6 of this invention. Detailed Implementation
[0021] See Figure 1 The present invention provides a method for improving foaming during the carbonization process of high-titanium blast furnace slag, comprising the following steps: Step 1) Add a portion of the dried carbonaceous reducing agent to the first crucible beforehand.
[0022] The dried carbonaceous reducing agent is obtained by drying it in an oven at a temperature of 100℃-110℃ for 3-5 hours.
[0023] The mass of the dried carbonaceous reducing agent pre-added to the first crucible is 7%-9% of the mass of the high-titanium blast furnace slag used for smelting.
[0024] In a preferred embodiment of the present invention, the mass of the dried carbonaceous reducing agent pre-added to the first crucible is 8% of the mass of the high-titanium blast furnace slag used for smelting.
[0025] Furthermore, the fixed carbon content of the dried carbonaceous reducing agent shall not be less than 75%, and the ash content shall not be more than 20%.
[0026] Step 2) After mixing the dried high-titanium blast furnace slag with the composite additive, put it into the second crucible.
[0027] The high-titanium blast furnace slag was dried in an oven at 100℃-110℃ for 3-5 hours.
[0028] High-titanium blast furnace slag is blast furnace slag with a TiO2 content of 15%-30%.
[0029] The composite additives include fluorite, borides (B2O3), quicklime, lightly calcined magnesite, and MnO. The composite additives function to modify the slag during the high-titanium blast furnace slag smelting process, increasing the slag surface tension, optimizing the transformation process of Ti-containing phases, reducing TiC enrichment, lowering the reaction temperature and the melting temperature of the slag system, thereby further reducing slag viscosity and improving fluidity.
[0030] Specifically, the fluorite (CaF2) and borides (B2O3) components in the composite additive can refine the TiC grain size, reduce TiC aggregation, lower the apparent viscosity of the slag, effectively improve slag fluidity, and simultaneously lower the melting temperature of the slag system, thus reducing the reaction temperature to some extent and allowing the reaction to proceed in the forward direction. The quicklime, lightly calcined magnesite, and MnO components in the composite additive can prevent excessive reduction of TiO2 in the early stages, further reducing TiC enrichment.
[0031] The composite additives, by mass percentage, include 40%-60% fluorite, 15%-25% borides, 10%-20% quicklime, 5%-15% lightly calcined magnesite, and 2%-8% MnO.
[0032] In a preferred embodiment of the present invention, the composite additive comprises, by weight percentage, 50% fluorite, 20% boride (B2O3), 15% quicklime, 10% lightly calcined magnesite, and 5% MnO.
[0033] Furthermore, the mass of the composite additive is 2%-6% of the mass of the high-titanium blast furnace slag.
[0034] As a preferred embodiment of the present invention, the mass of the composite additive is preferably 4% of the mass of the high-titanium blast furnace slag.
[0035] Step 3) Place the second crucible in a resistance furnace and heat it until the high-titanium blast furnace slag melts, then pour it into the first crucible; The second crucible is placed in a resistance furnace and heated to a temperature of 1250℃-1350℃ to melt the high-titanium blast furnace slag.
[0036] In a preferred embodiment of the present invention, the temperature at which the second crucible is placed in a resistance furnace and heated to melt the high-titanium blast furnace slag is preferably 1300°C.
[0037] Step 4) Place the first crucible in a resistance furnace and heat it to 1400℃-1500℃ for carbonization reaction for 1.5h-2.5h.
[0038] In a preferred embodiment of the present invention, the temperature of the resistance furnace in the carbonization reaction of step 4) is preferably raised to 1450°C, and the carbonization reaction time is preferably 2 hours.
[0039] In this process, after the first crucible is placed in a resistance furnace and heated to 1400℃-1500℃ for carbonization reaction for 1.5h-2h, 70%-90% of the TiO2 in the high-titanium blast furnace slag is reduced to low-valent titanium oxides.
[0040] In a preferred embodiment of the present invention, the reduction endpoint of the carbonization reaction in the first crucible placed in the resistance furnace is when 80% of the TiO2 in the high-titanium blast furnace slag is reduced to low-valence titanium oxides.
[0041] Step 5) Heat the resistance furnace to 1550℃-1650℃, and at the same time add the remaining carbonaceous reducing agent into the first crucible for carbonization reaction for 0.2h-1h to obtain carbonized slag.
[0042] The remaining dried carbonaceous reducing agent is added to the first crucible via a charging funnel.
[0043] The mass of the remaining dried carbonaceous reducing agent added to the first crucible is 4%-6% of the mass of the high-titanium blast furnace slag.
[0044] As a preferred embodiment of the present invention, the mass of the remaining dried carbonaceous reducing agent added to the first crucible is preferably 5% of the mass of the high-titanium blast furnace slag.
[0045] In a preferred embodiment of the present invention, the temperature of the resistance furnace in step 5) carbonization reaction is preferably raised to 1500°C, and the carbonization reaction time is preferably 0.5 h.
[0046] Step 6) The obtained carbonized slag is rapidly cooled to obtain the carbonized slag product.
[0047] This invention provides a method for improving foaming during the carbonization process of high-titanium blast furnace slag. During smelting, the carbonization process is optimized through gradient optimization. Specifically, a portion of carbonaceous reducing agent is added to the crucible in the early stages of smelting. Then, the high-titanium blast furnace slag with added composite additives is heated and melted, then poured into the crucible pre-filled with the carbonaceous reducing agent. The temperature is rapidly increased to initiate the carbonization reaction, reducing TiO2 to low-valent titanium oxide (TiC). By directionally controlling the reaction process of the Ti-containing phase, early TiC enrichment can be suppressed at the source, reducing the core inducing factors of foaming. This also ensures optimized TiC particle size and efficient preparation. Furthermore, the reaction process of the Ti-containing phase can be controlled to reduce slag viscosity and improve foaming, creating favorable kinetic conditions that facilitate timely CO gas discharge and effectively reduce the degree of foaming.
[0048] In the later stages of smelting, the remaining carbonaceous reducing agent is added to the crucible, which can further effectively break up the bubbles generated by the reaction, creating favorable kinetic conditions. This facilitates the timely discharge of CO gas, reduces the viscosity of the molten slag, and inhibits the formation of foamy slag, thereby effectively improving the foaming process in the carbonization of high-titanium blast furnace slag.
[0049] This invention provides a method for improving foaming during the carbonization process of high-titanium blast furnace slag. By gradient optimization of the carbonization process and the addition of composite additives, a synergistic modification of the slag's physicochemical properties is achieved. This method not only suppresses the core cause of foaming (early TiC enrichment) at its source but also ensures optimized TiC particle size and efficient preparation. It also regulates the reaction process of the Ti-containing phase, thereby reducing slag viscosity and improving foaming, thus enhancing slag fluidity and laying the foundation for a smooth smelting process. Simultaneously, the addition of composite additives lowers the reaction temperature, which is beneficial for increasing the carbonization rate and reducing smelting power consumption.
[0050] Therefore, the present invention provides a method for improving foaming during the carbonization process of high-titanium blast furnace slag, which can effectively solve the problems of severe foaming, difficult heat and mass transfer, and high energy consumption during the carbonization process of high-titanium slag. It can significantly reduce slag viscosity and the degree of slag foaming, while increasing the carbonization rate and improving slag fluidity, thus ensuring smooth smelting. This provides a feasible technical path for the smooth carbonization process of high-titanium blast furnace slag, and also reduces energy consumption, saves production costs, and improves economic efficiency, making it worthy of widespread application.
[0051] The following examples and comparative examples illustrate a method for improving foaming during the carbonization process of high-titanium blast furnace slag provided by the present invention.
[0052] Comparative Example The high-titanium blast furnace slag with the composition shown in Table 1 and the carbonaceous reducing agent with the composition shown in Table 2 were thoroughly mixed and placed in a crucible. The carbonaceous reducing agent was added at a ratio of 13% of the molten slag mass. The crucible was placed in an electric resistance furnace and heated to 1600℃ for 3 hours. After holding at that temperature, the mixture was rapidly cooled to obtain a carburized slag with a carbonization rate of approximately 83%. The maximum molten slag expansion coefficient during the smelting process was approximately 5.4 (the ratio of the maximum height of the foamy slag to the original slag height). Significant slag overflow occurred during the carbonization process, resulting in high power consumption throughout the smelting process.
[0053] The microstructure of the carbonized slag obtained in the comparative example of this invention is as follows: Figure 2 As shown.
[0054] Table 1. Main component indicators of comparative high-titanium blast furnace slag / wt.%
[0055] Table 2. Main component indicators of comparative carbonaceous reducing agents / wt.%
[0056] Example 1 Example 1 of this invention uses the same high-titanium blast furnace slag and carbonaceous reducing agent as the comparative example, as detailed in Tables 1 and 2. The composite additive used in Example 1 consists of 40% fluorite, 25% boride (B₂O₃), 20% quicklime, 7% lightly calcined magnesite, and 8% MnO. The specific operation of Example 1 is as follows.
[0057] A portion of carbonaceous reducing agent, at a ratio of 8% of the high-titanium slag mass, was pre-placed in crucible No. 1. High-titanium blast furnace slag was then added to crucible No. 2, along with a certain amount of composite additive, at a ratio of 3% of the high-titanium slag mass. The mixture was thoroughly combined and heated to 1300℃. After the high-titanium slag had completely melted, it was poured into crucible No. 1 containing the carbonaceous reducing agent. The crucible was then transferred to an electric resistance furnace and heated further to 1500℃, holding at that temperature for 2 hours.
[0058] After the initial heat treatment, the temperature was increased further. During this process, a carbonaceous reducing agent was added to the crucible through a charging funnel at a ratio of 5% of the high-titanium slag mass. Once the molten slag temperature reached 1600℃, it was held at this temperature for 30 minutes. After the heat treatment, the slag was rapidly cooled to obtain a carbide slag with a carbonization rate of approximately 84%. The maximum molten slag expansion coefficient during the smelting process was approximately 3.8, and there was no slag overflow.
[0059] The microstructure of the carbonized slag obtained in the embodiments of the present invention is as follows: Figure 3 As shown.
[0060] Example 2 Example 2 of this invention uses the same high-titanium blast furnace slag and carbonaceous reducing agent as the comparative example, as detailed in Tables 1 and 2. The composite additive used in Example 2 consists of 40% fluorite, 25% boride (B₂O₃), 20% quicklime, 7% lightly calcined magnesite, and 8% MnO. The specific operation of Example 2 is as follows.
[0061] A portion of carbonaceous reducing agent, at a ratio of 8% of the high-titanium slag mass, was pre-placed in crucible No. 1. High-titanium blast furnace slag was then added to crucible No. 2, along with a certain amount of composite additive, at a ratio of 3% of the high-titanium slag mass. The mixture was thoroughly combined and heated to 1300℃. After the high-titanium slag had completely melted, it was poured into crucible No. 1 containing the carbonaceous reducing agent. The crucible was then transferred to an electric resistance furnace and heated further to 1400℃, holding at that temperature for 2 hours.
[0062] After the initial heat treatment, the temperature was increased further. During this process, a carbonaceous reducing agent was added to the crucible through a charging funnel at a ratio of 5% of the high-titanium slag mass. Once the molten slag temperature reached 1600℃, it was held at this temperature for 30 minutes. After the heat treatment, the slag was rapidly cooled to obtain a carbide slag with a carbonization rate of approximately 85%. The maximum molten slag expansion coefficient during the smelting process was approximately 3.6, and there was no slag overflow.
[0063] The microstructure of the carbonized slag obtained in the embodiments of the present invention is as follows: Figure 4 As shown.
[0064] Example 3 Example 3 of this invention uses the same high-titanium blast furnace slag and carbonaceous reducing agent as the comparative example, as detailed in Tables 1 and 2. The composite additive used in Example 3 consists of 40% fluorite, 25% boride (B₂O₃), 20% quicklime, 7% lightly calcined magnesite, and 8% MnO. The specific operation of Example 3 is as follows.
[0065] A portion of carbonaceous reducing agent, at a ratio of 9% of the high-titanium slag mass, was pre-placed in crucible No. 1. High-titanium blast furnace slag was then added to crucible No. 2, along with a certain amount of composite additive, at a ratio of 3% of the high-titanium slag mass. The mixture was thoroughly combined and heated to 1300℃. After the high-titanium slag had completely melted, it was poured into crucible No. 1 containing the carbonaceous reducing agent. The crucible was then transferred to an electric resistance furnace and heated further to 1450℃, holding at that temperature for 2 hours.
[0066] After the initial heat treatment, the temperature was increased further. During this process, a carbonaceous reducing agent was added to the crucible through a charging funnel at a ratio of 4% of the high-titanium slag mass. Once the molten slag temperature reached 1600℃, it was held at this temperature for 30 minutes. After the heat treatment, the slag was rapidly cooled to obtain a carbide slag with a carbonization rate of approximately 86%. The maximum molten slag expansion coefficient during the smelting process was approximately 3.2, and there was no slag overflow.
[0067] The microstructure of the carbonized slag obtained in the embodiments of the present invention is as follows: Figure 5 As shown.
[0068] Example 4 Example 4 of this invention uses the same high-titanium blast furnace slag and carbonaceous reducing agent as the comparative example, as detailed in Tables 1 and 2. The composite additive used in Example 4 consists of 40% fluorite, 25% boride (B₂O₃), 20% quicklime, 7% lightly calcined magnesite, and 8% MnO. The specific operation of Example 4 is as follows.
[0069] A portion of carbonaceous reducing agent, at a ratio of 8% of the high-titanium slag mass, was pre-placed in crucible No. 1. High-titanium blast furnace slag was then added to crucible No. 2, along with a certain amount of composite additive, at a ratio of 3% of the high-titanium slag mass. The mixture was thoroughly combined and heated to 1300℃. After the high-titanium slag had completely melted, it was poured into crucible No. 1 containing the carbonaceous reducing agent. The crucible was then transferred to an electric resistance furnace and heated further to 1450℃, holding at that temperature for 2 hours.
[0070] After the initial heat treatment, the temperature was increased further. During this process, a carbonaceous reducing agent was added to the crucible through a charging funnel at a ratio of 5% of the high-titanium slag mass. Once the molten slag temperature reached 1600℃, it was held at this temperature for 30 minutes. After the heat treatment, the slag was rapidly cooled to obtain a carbide slag with a carbonization rate of approximately 87%. The maximum molten slag expansion coefficient during the smelting process was approximately 2.8, and there was no slag overflow.
[0071] The microstructure of the carbonized slag obtained in the embodiments of the present invention is as follows: Figure 6 As shown.
[0072] Example 5 Example 5 of this invention uses the same high-titanium blast furnace slag and carbonaceous reducing agent as the comparative example, as detailed in Tables 1 and 2. The composite additive used in Example 5 consists of 50% fluorite, 20% boride (B₂O₃), 15% quicklime, 10% lightly calcined magnesite, and 5% MnO. The specific operation of Example 5 is as follows.
[0073] A portion of carbonaceous reducing agent, at a ratio of 8% of the high-titanium slag mass, was pre-placed in crucible No. 1. High-titanium blast furnace slag was then added to crucible No. 2, along with a certain amount of composite additive, at a ratio of 3% of the high-titanium slag mass. The mixture was thoroughly combined and heated to 1300℃. After the high-titanium slag had completely melted, it was poured into crucible No. 1 containing the carbonaceous reducing agent. The crucible was then transferred to an electric resistance furnace and heated further to 1450℃, holding at that temperature for 2 hours.
[0074] After the initial heat treatment, the temperature was increased further. During this process, a carbonaceous reducing agent was added to the crucible through a charging funnel at a ratio of 5% of the high-titanium slag mass. Once the molten slag temperature reached 1600℃, it was held at this temperature for 30 minutes. After the heat treatment, the slag was rapidly cooled to obtain a carbide slag with a carbonization rate of approximately 88%. The maximum molten slag expansion coefficient during the smelting process was approximately 2.6, and there was no slag overflow.
[0075] The microstructure of the carbonized slag obtained in the embodiments of the present invention is as follows: Figure 7 As shown.
[0076] Example 6 Example 6 of this invention uses the same high-titanium blast furnace slag and carbonaceous reducing agent as the comparative example, as detailed in Tables 1 and 2. The composite additive used in Example 6 consists of 50% fluorite, 20% boride (B₂O₃), 15% quicklime, 10% lightly calcined magnesite, and 5% MnO. The specific operation of Example 6 is as follows.
[0077] A portion of carbonaceous reducing agent, at a ratio of 8% of the high-titanium slag mass, was pre-placed in crucible No. 1. High-titanium blast furnace slag was then added to crucible No. 2, along with a certain amount of composite additive, at a ratio of 4% of the high-titanium slag mass. The mixture was thoroughly combined and heated to 1300℃. After the high-titanium slag had completely melted, it was poured into crucible No. 1 containing the carbonaceous reducing agent. The crucible was then transferred to an electric resistance furnace and heated further to 1450℃, holding at that temperature for 2 hours.
[0078] After the initial heat treatment, the temperature was increased further. During this process, a carbonaceous reducing agent was added to the crucible through a charging funnel at a ratio of 5% of the high-titanium slag mass. Once the molten slag temperature reached 1600℃, it was held at this temperature for 30 minutes. After the heat treatment, the slag was rapidly cooled to obtain a carbide slag with a carbonization rate of approximately 89%. The maximum molten slag expansion coefficient during the smelting process was approximately 2.4, and there was no slag overflow.
[0079] The microstructure of the carbonized slag obtained in the embodiments of the present invention is as follows: Figure 8 As shown.
[0080] See Figures 2-8 People with the same gray level represent the same phase. Figures 2-8 It can be seen that the carbonized slag obtained in the comparative examples and Examples 1-6 of this invention typically has three phases, as indicated by dots 1, 2, and 3. Figures 2-8 The white particles marked at point 2 represent TiC grains.
[0081] in, Figures 2-8 The composition of the three phases represented by points 1, 2, and 3 is shown in Table 3.
[0082] Table 3. Composition of the three phases represented by points 1, 2, and 3.
[0083] contrast Figures 2-8 It can be seen that the TiC grains in the carbide slag obtained in the comparative example are relatively concentrated, while the TiC grains in the carbide slag obtained in Examples 1-6 have a relatively low degree of aggregation. The TiC grains with a lower degree of aggregation are beneficial to reducing the viscosity of the carbide slag, increasing the surface tension of the carbide slag, improving the fluidity of the carbide slag, and significantly improving the foaming of the high-titanium slag carbide process.
[0084] Therefore, by comparing the comparative examples and Examples 1-6, it can be seen that the method for improving foaming during the carbonization process of high-titanium blast furnace slag provided by the embodiments of the present invention, by controlling the temperature, ensures that the carbonization and reduction of high-titanium blast furnace slag proceeds stepwise according to the TiO2 stepwise reduction reaction. In the early stage, by controlling the reaction temperature at 1400℃-1500℃, the titanium is present in its lowest valence oxide form as much as possible, avoiding the generation of a large amount of CO gas at once, and ensuring that the slag is basically free of TiC solid particles. After the first CO gas discharge, the temperature is rapidly increased to 1550℃-1650℃ to quickly convert the low valence oxide of titanium into TiC. At this time, the slag temperature is high, the viscosity is low, the molten pool churns more violently, and the reaction kinetics are better, which to some extent facilitates the rapid discharge of CO gas. During this period, the remaining carbonaceous reducing agent is added to the molten pool through the charging funnel, giving the reducing agent particles a certain initial velocity, thereby breaking up the bubbles generated during the carbonization process and effectively improving foaming during the smelting process. The composite additive refines TiC grains, reduces TiC particle agglomeration, regulates the reaction process of Ti-containing phases, avoids the formation of fine TiC grains at low temperatures, reduces viscosity, and improves slag fluidity. On the other hand, it helps lower the reaction initiation temperature, increases the carbonization rate, and reduces power consumption during the smelting process.
[0085] 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 and substitutions should be covered within the scope of the present invention.
Claims
1. A method for improving foaming during the carbonization process of high-titanium blast furnace slag, characterized in that, Includes the following steps: A portion of the dried carbonaceous reducing agent is added to the first crucible beforehand; The dried high-titanium blast furnace slag was mixed with the composite additive and then placed into the second crucible. The second crucible is placed in a resistance furnace and heated until the high-titanium blast furnace slag melts, then poured into the first crucible. The first crucible is placed in an electric resistance furnace and heated to 1400℃-1500℃ for carbonization reaction for 1.5h-2.5h; The resistance furnace is heated to 1550℃-1650℃, and the remaining carbonaceous reducing agent is added to the first crucible for carbonization reaction for 0.2h-1h to obtain carbonized slag. The obtained carbonized slag is rapidly cooled to obtain the carbonized slag product.
2. The method for improving foaming during the carbonization process of high-titanium blast furnace slag according to claim 1, characterized in that, The carbonaceous reducing agent is dried in an oven at 100℃-110℃ for 3-5 hours, and the high-titanium blast furnace slag is dried in an oven at 100℃-110℃ for 3-5 hours.
3. The method for improving foaming during the carbonization process of high-titanium blast furnace slag according to claim 1, characterized in that, The carbonaceous reducing agent has a fixed carbon content of not less than 75% and an ash content of not more than 20%.
4. The method for improving foaming during the carbonization process of high-titanium blast furnace slag according to claim 1, characterized in that, The mass of the carbonaceous reducing agent pre-added to the first crucible is 7%-9% of the mass of the high-titanium blast furnace slag.
5. The method for improving foaming during the carbonization process of high-titanium blast furnace slag according to claim 1, characterized in that, The composite additive comprises, by weight percentage, 40%-60% fluorite, 15%-25% borides, 10%-20% quicklime, 5%-15% lightly calcined magnesite, and 2%-8% MnO.
6. The method for improving foaming during the carbonization process of high-titanium blast furnace slag according to claim 5, characterized in that, The mass of the composite additive is 2%-6% of the mass of the high-titanium blast furnace slag.
7. The method for improving foaming during the carbonization process of high-titanium blast furnace slag according to claim 1, characterized in that, The second crucible is placed in a resistance furnace and heated to a temperature of 1250℃-1350℃.
8. The method for improving foaming during the carbonization process of high-titanium blast furnace slag according to claim 1, characterized in that, After the first crucible is placed in a resistance furnace and heated to 1400℃-1500℃ for carbonization reaction for 1.5h-2h, 70%-90% of the TiO2 in the high-titanium blast furnace slag is reduced to low-valence titanium oxides.
9. The method for improving foaming during the carbonization process of high-titanium blast furnace slag according to claim 1, characterized in that, The remaining dried carbonaceous reducing agent is added to the first crucible via a charging funnel.
10. The method for improving foaming during the carbonization process of high-titanium blast furnace slag according to claim 9, characterized in that, The mass of the remaining dried carbonaceous reducing agent added to the first crucible is 4%-6% of the mass of the high-titanium blast furnace slag.