A method of forming a high temperature resistant erosion resistant furnace bottom

Abstract

The present application belongs to the field of extracting titanium from blast furnace slag, and particularly relates to a forming method of a high-temperature-resistant and erosion-resistant furnace bottom, which comprises the following steps: forming a high-temperature-resistant and erosion-resistant furnace bottom above refractory bricks at the bottom of an electric furnace, wherein the high-temperature-resistant and erosion-resistant furnace bottom comprises a base and high-melting-point solid phases formed on the base. The present application forms the high-temperature-resistant and erosion-resistant furnace bottom as a "false furnace bottom" by generating the high-melting-point solid phases, and the high-temperature-resistant and erosion-resistant furnace bottom has the use performance of high-quality refractory materials, can block the direct contact between the molten blast furnace slag containing titanium and the refractory bricks at the bottom of the electric furnace, slow down the erosion and consumption speed of the refractory bricks at the bottom of the electric furnace, and thus prolong the service life of the refractory bricks. Meanwhile, a large amount of solid wastes such as fly ash and solid blast furnace slag containing titanium are used, and the environmental protection benefit is remarkable.

Description

Technical Field

[0001] This invention belongs to the field of titanium extraction from blast furnace slag, and particularly relates to a method for forming a furnace bottom that is resistant to high temperature and corrosion. Background Technology

[0002] Currently, existing technologies typically employ AC electric furnaces with carbon-based smelting of titanium-containing blast furnace slag, aiming to convert TiO2 in the slag into TiC. However, based on current large-scale production, the service life of the refractory bricks at the furnace bottom in this technology is relatively short. This is because the TiO2 in the titanium-containing blast furnace slag reacts rapidly with alumina, magnesia, carbonaceous, and magnesia-carbonaceous refractory bricks at smelting temperatures of 1400–1700℃, leading to significant erosion. Simultaneously, the continuous downward movement of the graphite electrodes during smelting causes the furnace's hot zone to shift downwards, requiring the furnace bottom refractory bricks to withstand higher smelting temperatures than the furnace wall refractory bricks, further accelerating the erosion rate.

[0003] Therefore, existing technologies still need improvement. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, in order to extend the service life of the AC electric furnace lining and prevent the titanium-containing molten blast furnace slag from directly contacting the refractory bricks at the bottom of the electric furnace, the technical problem to be solved by the present invention is to provide a "false furnace bottom" forming method, that is, a forming method for a furnace bottom that is resistant to high temperature and corrosion.

[0005] An embodiment of the present invention provides a method for forming a high-temperature resistant and corrosion-resistant furnace bottom, comprising the following steps: forming the high-temperature resistant and corrosion-resistant furnace bottom above the refractory bricks at the bottom of an electric furnace, wherein the high-temperature resistant and corrosion-resistant furnace bottom comprises a substrate and a high-melting-point solid phase formed on the substrate.

[0006] In an embodiment of the present invention, the step of forming the high-temperature resistant and erosion-resistant furnace bottom above the refractory bricks at the bottom of the electric furnace includes: S10. providing additional refractory bricks as the base of the high-temperature resistant and erosion-resistant furnace bottom, wherein the thickness of the additional refractory bricks is 1 / 2 to 3 / 4 of the thickness of the refractory bricks; S20. depositing material on the base, wherein the height of the deposited material is 1 / 4 to 1 / 2 of the thickness of the refractory bricks; S30. smelting the material; S40. after smelting is completed, allowing the slag to cool naturally to room temperature to obtain the high-melting-point solid phase, wherein the base and the high-melting-point solid phase constitute the high-temperature resistant and erosion-resistant furnace bottom.

[0007] In an embodiment of the present invention, in step S10, the thickness of the additional refractory brick is 2 / 3 of the thickness of the refractory brick, and the material of the additional refractory brick is the same as that of the refractory brick; in step S20, the height of the stacked material is 1 / 3 of the thickness of the refractory brick.

[0008] In an embodiment of the present invention, in step S20, the materials include titanium-containing raw materials, fly ash, solid titanium-containing blast furnace slag, and carbonaceous reducing agent.

[0009] In embodiments of the present invention, the titanium-containing raw material contains ≥70% TiO2 by mass percentage, and the titanium-containing raw material includes at least one of titanium dioxide, high-titanium slag, and titanium-rich material; the fly ash is solid waste from thermal power plants, including 15-40% Al2O3 by mass percentage and 34-65% SiO2 by mass percentage; the solid titanium-containing blast furnace slag contains 10-28% TiO2 by mass percentage; the carbonaceous reducing agent includes coke powder, semi-coke, or anthracite.

[0010] In an embodiment of the present invention, the mass ratio of the titanium-containing raw material, the fly ash, the titanium-containing blast furnace slag, and the carbonaceous reducing agent is 5:1.5-2.5:1.5-2.5:3-4.

[0011] In an embodiment of the present invention, in step S30, the smelting process is mainly based on the reaction 3C+TiO2=2CO+TiC, and the reaction temperature is ≥1500℃.

[0012] In an embodiment of the present invention, in step S40, the criterion for determining the end of smelting is that the volume percentage of CO gas produced by the reaction is ≤10%.

[0013] In an embodiment of the present invention, in step S40, the time required for the molten slag to cool naturally to room temperature is ≥48h, and no other rapid cooling measures are required during the cooling process.

[0014] In an embodiment of the present invention, the high-melting-point solid phase comprises TiC, MgAl2O4 and CaTiO3, and the mass percentage content of TiC is ≥35%.

[0015] This invention utilizes the principle of carbothermic reduction reaction between TiO2 and carbonaceous reducing agents under high-temperature conditions to produce TiC, which has a high melting point, extremely strong corrosion resistance, and high viscosity. Simultaneously, during the slow cooling of the molten slag, high-melting-point solid phases such as MgAl2O4 and CaTiO3, which exhibit good slag resistance and high-temperature resistance, further precipitate. The "false furnace bottom" composed of TiC, MgAl2O4, and CaTiO3 possesses the performance characteristics of high-quality refractory materials, preventing direct contact between titanium-containing molten blast furnace slag and the furnace bottom refractory bricks, slowing down the erosion and consumption rate of the furnace bottom refractory bricks, and thus extending their service life. Furthermore, due to the extensive use of fly ash and solid titanium-containing blast furnace slag, significant environmental benefits are achieved. Attached Figure Description

[0016] Figure 1A schematic flowchart of the forming method for the high-temperature resistant and corrosion-resistant furnace bottom provided in an embodiment of the present invention is shown. Detailed Implementation

[0017] It should be understood that the embodiments of the invention shown in the exemplary embodiments are merely illustrative. Although only a few embodiments have been described in detail in this invention, those skilled in the art will readily recognize that various modifications are possible without substantially departing from the teachings of the invention. Accordingly, all such modifications should be included within the scope of the invention. Other substitutions, modifications, variations, and deletions can be made to the design, operating conditions, and parameters of the following exemplary embodiments without departing from the spirit of the invention.

[0018] To extend the service life of AC furnace linings, the most effective method is to prevent direct contact between titanium-containing molten blast furnace slag and the refractory bricks at the furnace bottom, forming a transition layer with high melting point and high viscosity that does not contaminate the target product, also known as a "false furnace bottom".

[0019] Specifically, according to the present invention, a method for forming a high-temperature resistant and corrosion-resistant furnace bottom is provided, such as... Figure 1 As shown, it includes the following steps: forming the high-temperature resistant and erosion-resistant furnace bottom above the refractory bricks at the bottom of the electric furnace, wherein the high-temperature resistant and erosion-resistant furnace bottom includes a substrate and a high-melting-point solid phase formed on the substrate. This invention generates a high-melting-point solid phase to form a high-temperature resistant and erosion-resistant furnace bottom as a "false furnace bottom." This high-temperature resistant and erosion-resistant furnace bottom possesses the performance characteristics of high-quality refractory materials, can prevent direct contact between titanium-containing molten blast furnace slag and the refractory bricks at the bottom of the electric furnace, slows down the rate of erosion and consumption of the refractory bricks at the bottom of the electric furnace, and thus extends its service life.

[0020] In embodiments of the present invention, further as follows: Figure 1 As shown, the step of forming the high-temperature resistant and erosion-resistant furnace bottom above the refractory bricks at the bottom of the electric furnace includes:

[0021] S10. Provide additional refractory bricks as the base of the high-temperature resistant and erosion-resistant furnace bottom, wherein the thickness of the additional refractory bricks is 1 / 2 to 3 / 4 of the thickness of the refractory bricks;

[0022] S20. Material is deposited on the substrate, and the height of the deposited material is 1 / 4 to 1 / 2 of the thickness of the refractory brick;

[0023] S30. Melt the material;

[0024] S40. After the smelting is completed, allow the slag to cool naturally to room temperature to obtain the high-melting-point solid phase. The substrate and the high-melting-point solid phase constitute the high-temperature resistant and corrosion-resistant furnace bottom.

[0025] In an embodiment of the present invention, in step S10, the thickness of the additional refractory brick is 2 / 3 of the thickness of the refractory brick, and the material of the additional refractory brick is the same as the material of the refractory brick, that is, the material commonly used in refractory bricks in the prior art can be used; in step S20, the height of the stacked material is 1 / 3 of the thickness of the refractory brick.

[0026] In an embodiment of the present invention, in step S20, the materials include titanium-containing raw materials, fly ash, solid titanium-containing blast furnace slag, and carbonaceous reducing agent.

[0027] In embodiments of the present invention, the titanium-containing raw material contains ≥70% TiO2 by mass percentage, and the titanium-containing raw material includes at least one of titanium dioxide, high-titanium slag, and titanium-rich material; the fly ash is solid waste from thermal power plants, including 15-40% Al2O3 by mass percentage and 34-65% SiO2 by mass percentage; the solid titanium-containing blast furnace slag contains 10-28% TiO2 by mass percentage; the carbonaceous reducing agent includes coke powder, semi-coke, or anthracite.

[0028] In an embodiment of the present invention, the mass ratio of the titanium-containing raw material, the fly ash, the titanium-containing blast furnace slag, and the carbonaceous reducing agent is 5:1.5-2.5:1.5-2.5:3-4.

[0029] In an embodiment of the present invention, in step S30, the smelting process is mainly based on the reaction 3C+TiO2=2CO+TiC, and the reaction temperature is ≥1500℃.

[0030] In an embodiment of the present invention, in step S40, the criterion for determining the end of smelting is that the volume percentage of CO gas produced by the reaction is ≤10%.

[0031] In an embodiment of the present invention, in step S40, the time required for the molten slag to cool naturally to room temperature is ≥48h, and no other rapid cooling measures are required during the cooling process.

[0032] In an embodiment of the present invention, the high-melting-point solid phase comprises TiC, MgAl2O4 and CaTiO3, and the mass percentage content of TiC is ≥35%.

[0033] Typically, an AC electric furnace is used for smelting titanium-containing blast furnace slag with carbon, and the thickness of the refractory bricks at the furnace bottom is approximately 500mm to 2500mm. The high-temperature and erosion-resistant furnace bottom constructed in this invention is approximately 1 / 2 to 3 / 4 (preferably 2 / 3) the thickness of the refractory bricks at the furnace bottom. A space of 1 / 4 to 1 / 2 (preferably 1 / 3) is reserved for accumulating a mixture of titanium-containing raw materials with a TiO2 content ≥70%, fly ash, solid titanium-containing blast furnace slag, and carbonaceous reducing agents. Arc ignition and smelting are then carried out. The smelting process is mainly based on the reaction 3C + TiO2 = 2CO + TiC. The target product TiC is a high-melting-point solid phase in this reaction system, with a melting temperature ≥3100℃. The reaction is considered complete when the CO content in the gas produced by the reaction significantly decreases. Afterward, the slag is gradually and slowly cooled to room temperature. During the cooling process, a large amount of new phases with good erosion resistance, slag resistance, and high-temperature resistance, such as MgAl2O4 and CaTiO3, are generated. The high-temperature resistant and corrosion-resistant "false furnace bottom" has been basically completed, and subsequent smelting production can begin.

[0034] The present invention is illustrated below through specific embodiments:

[0035] Example 1

[0036] The present invention discloses a method for forming a high-temperature resistant and corrosion-resistant furnace bottom, comprising: forming a high-temperature resistant and corrosion-resistant furnace bottom above refractory bricks at the bottom of an electric furnace, wherein the high-temperature resistant and corrosion-resistant furnace bottom includes a substrate and a high-melting-point solid phase formed on the substrate. Specifically, the step of forming the high-temperature resistant and corrosion-resistant furnace bottom above refractory bricks at the bottom of the electric furnace includes:

[0037] (1) Provide additional refractory bricks as the base of the furnace bottom that is resistant to high temperature and corrosion, the thickness of which is 1 / 2 the thickness of the refractory bricks at the bottom of the electric furnace.

[0038] (2) Material is piled up on the base, with the height of the pile being 1 / 2 the thickness of the refractory bricks at the bottom of the electric furnace. The material includes a mixture of titanium-containing raw materials, fly ash, solid titanium-containing blast furnace slag, and carbonaceous reducing agent. The titanium-containing raw materials include titanium dioxide with a TiO2 mass percentage content ≥70%; the fly ash mainly comes from solid waste from thermal power plants, including Al2O3 with a mass percentage content of 15% and SiO2 of 65%; the solid titanium-containing blast furnace slag contains TiO2 with a mass percentage content of 10%; the carbonaceous reducing agent can be coke powder. The mass ratio of titanium-containing raw materials: fly ash: titanium-containing blast furnace slag: carbonaceous reducing agent is 5:1.5:1.5:3.

[0039] (3) Then, the material is smelted by arc initiation. The reaction temperature of the smelting process is 1500℃. The smelting process is mainly based on the reaction 3C+TiO2=2CO+TiC. The target product TiC is a high melting point solid in this reaction system, and its melting temperature is ≥3100℃.

[0040] (4) When the CO content in the gas produced by the reaction decreases significantly (e.g., volume content ≤ 10%), the reaction can be considered complete, i.e., the smelting is finished. After smelting, allow the slag to cool naturally to room temperature (e.g., 48 hours). The cooling process will produce a large amount of MgAl2O4, CaTiO3, and other high-melting-point solids with good erosion resistance, slag resistance, and high temperature resistance. The base and the high-melting-point solids constitute a high-temperature and erosion-resistant furnace bottom, in which the mass percentage of TiC is ≥ 35%. The high-temperature and erosion-resistant "false furnace bottom" is basically formed, and subsequent smelting production can be carried out.

[0041] Example 2

[0042] The present invention discloses a method for forming a high-temperature resistant and corrosion-resistant furnace bottom, comprising: forming a high-temperature resistant and corrosion-resistant furnace bottom above refractory bricks at the bottom of an electric furnace, wherein the high-temperature resistant and corrosion-resistant furnace bottom includes a substrate and a high-melting-point solid phase formed on the substrate. Specifically, the step of forming the high-temperature resistant and corrosion-resistant furnace bottom above refractory bricks at the bottom of the electric furnace includes:

[0043] (1) Provide additional refractory bricks as the base of the furnace bottom that is resistant to high temperature and corrosion, the thickness of which is 3 / 4 of the thickness of the refractory bricks at the bottom of the electric furnace.

[0044] (2) Material is piled up on the base, with the height of the pile being 1 / 4 of the thickness of the refractory bricks at the bottom of the electric furnace. The material includes a mixture of titanium-containing raw materials, fly ash, solid titanium-containing blast furnace slag, and carbonaceous reducing agent. The titanium-containing raw materials include high-titanium slag with a TiO2 mass percentage content ≥70%; the fly ash mainly comes from solid waste from thermal power plants, including 40% Al2O3 and 34% SiO2 by mass percentage; the solid titanium-containing blast furnace slag contains 28% TiO2 by mass; and the carbonaceous reducing agent can be semi-coke. The mass ratio of titanium-containing raw materials: fly ash: titanium-containing blast furnace slag: carbonaceous reducing agent is 5:2.5:2.5:4.

[0045] (3) Then, the material is smelted by arc initiation. The reaction temperature of the smelting process is 1600℃. The smelting process is mainly based on the reaction 3C+TiO2=2CO+TiC. The target product TiC is a high melting point solid in this reaction system, and its melting temperature is ≥3100℃.

[0046] (4) When the CO content in the gas produced by the reaction decreases significantly (e.g., volume content ≤ 10%), the reaction can be considered complete, i.e., the smelting is finished. After smelting, allow the slag to cool naturally to room temperature (e.g., 48 hours). The cooling process will produce a large amount of MgAl2O4, CaTiO3, and other high-melting-point solids with good erosion resistance, slag resistance, and high temperature resistance. The base and the high-melting-point solids constitute a high-temperature and erosion-resistant furnace bottom, in which the mass percentage of TiC is ≥ 35%. The high-temperature and erosion-resistant "false furnace bottom" is basically formed, and subsequent smelting production can be carried out.

[0047] Example 3

[0048] The present invention discloses a method for forming a high-temperature resistant and corrosion-resistant furnace bottom, comprising: forming a high-temperature resistant and corrosion-resistant furnace bottom above refractory bricks at the bottom of an electric furnace, wherein the high-temperature resistant and corrosion-resistant furnace bottom includes a substrate and a high-melting-point solid phase formed on the substrate. Specifically, the step of forming the high-temperature resistant and corrosion-resistant furnace bottom above refractory bricks at the bottom of the electric furnace includes:

[0049] (1) Provide additional refractory bricks as the base of the furnace bottom that is resistant to high temperature and corrosion, the thickness of which is 2 / 3 of the thickness of the refractory bricks at the bottom of the electric furnace.

[0050] (2) Material is piled up on the base, with the height of the pile being 1 / 3 of the thickness of the refractory bricks at the bottom of the electric furnace. The material includes a mixture of titanium-containing raw materials, fly ash, solid titanium-containing blast furnace slag, and carbonaceous reducing agent. Among them, the titanium-containing raw materials include titanium-rich materials with a TiO2 mass percentage content ≥70%; the fly ash mainly comes from solid waste from thermal power plants, including Al2O3 with a mass percentage content of 25% and SiO2 of 50%; the solid titanium-containing blast furnace slag has a TiO2 mass percentage of 24%; the carbonaceous reducing agent can be anthracite. The mass ratio of titanium-containing raw materials: fly ash: titanium-containing blast furnace slag: carbonaceous reducing agent is 5:2:2:3.5.

[0051] (3) Then, the material is smelted by arc initiation. The reaction temperature of the smelting process is 1550℃. The smelting process is mainly based on the reaction 3C+TiO2=2CO+TiC. The target product TiC is a high-melting-point solid in this reaction system, and its melting temperature is ≥3100℃.

[0052] (4) When the CO content in the gas produced by the reaction decreases significantly (e.g., volume content ≤ 10%), the reaction can be considered complete, i.e., the smelting is finished. After smelting, allow the slag to cool naturally to room temperature (e.g., more than 48 hours). The cooling process will produce a large amount of MgAl2O4, CaTiO3, and other high-melting-point solids with good erosion resistance, slag resistance, and high temperature resistance. The base and the high-melting-point solids constitute a high-temperature and erosion-resistant furnace bottom, in which the mass percentage of TiC is ≥ 35%. The high-temperature and erosion-resistant "false furnace bottom" is basically formed, and subsequent smelting production can be carried out.

[0053] This invention utilizes the principle of carbothermic reduction reaction between TiO2 and carbonaceous reducing agents under high-temperature conditions to produce TiC, which has a high melting point, extremely strong corrosion resistance, and high viscosity. Simultaneously, during the slow cooling of the molten slag, high-melting-point solid phases such as MgAl2O4 and CaTiO3, which exhibit good slag resistance and high-temperature resistance, further precipitate. The "false furnace bottom" composed of TiC, MgAl2O4, and CaTiO3 possesses the performance characteristics of high-quality refractory materials, preventing direct contact between titanium-containing molten blast furnace slag and the furnace bottom refractory bricks, slowing down the erosion and consumption rate of the furnace bottom refractory bricks, and thus extending their service life. Furthermore, due to the extensive use of fly ash and solid titanium-containing blast furnace slag, significant environmental benefits are achieved.

[0054] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the present invention. Any modifications or equivalent substitutions made to the present invention without departing from the spirit and scope thereof should be covered within the protection scope of the claims of the present invention.

Claims

1. A method for forming a high-temperature resistant and corrosion-resistant furnace bottom, characterized in that, Includes the following steps: The high-temperature and erosion-resistant furnace bottom is formed above the refractory bricks at the bottom of the electric furnace, wherein the high-temperature and erosion-resistant furnace bottom includes a base and a high-melting-point solid phase formed on the base. The step of forming the high-temperature resistant and erosion-resistant furnace bottom above the refractory bricks at the bottom of the electric furnace includes: S10. providing additional refractory bricks as the base of the high-temperature resistant and erosion-resistant furnace bottom, wherein the thickness of the additional refractory bricks is 1 / 2 to 3 / 4 of the thickness of the refractory bricks; S20. Material is deposited on the substrate to a height of 1 / 4 to 1 / 2 of the thickness of the refractory brick. The material includes titanium-containing raw materials, fly ash, solid titanium-containing blast furnace slag, and a carbonaceous reducing agent. The titanium-containing raw materials contain at least 70% TiO2 by mass, and include at least one of titanium dioxide, high-titanium slag, and titanium-rich materials. The fly ash is solid waste from a thermal power plant, comprising 15-40% Al2O3 and 34-65% SiO2 by mass. The solid titanium-containing blast furnace slag contains 10-28% TiO2 by mass. The carbonaceous reducing agent includes coke powder, semi-coke, or anthracite. The mass ratio of the titanium-containing raw materials to the fly ash to the titanium-containing blast furnace slag to the carbonaceous reducing agent is 5:1.5-2.5:1.5-2.5:3-4. S30. The material is smelted. S40. After the smelting is completed, the slag is allowed to cool naturally to room temperature to obtain the high-melting-point solid phase. The substrate and the high-melting-point solid phase constitute the high-temperature resistant and corrosion-resistant furnace bottom.

2. The forming method for the high-temperature resistant and corrosion-resistant furnace bottom according to claim 1, characterized in that, In step S10, the thickness of the additional refractory brick is 2 / 3 of the thickness of the refractory brick, and the material of the additional refractory brick is the same as that of the refractory brick; in step S20, the height of the stacked material is 1 / 3 of the thickness of the refractory brick.

3. The forming method for the high-temperature resistant and corrosion-resistant furnace bottom according to claim 1, characterized in that, In step S30, the smelting process is mainly based on the reaction 3C+TiO2=2CO+TiC, and the reaction temperature is ≥1500℃.

4. The forming method for the high-temperature resistant and corrosion-resistant furnace bottom according to claim 3, characterized in that, In step S40, the criterion for determining the end of smelting is that the volume percentage of CO gas produced in the reaction is ≤10%.

5. The forming method for the high-temperature resistant and corrosion-resistant furnace bottom according to claim 1, characterized in that, In step S40, the time required for the molten slag to cool naturally to room temperature is ≥48h, and no other rapid cooling measures are required during the cooling process.

6. The method for forming a high-temperature resistant and corrosion-resistant furnace bottom according to any one of claims 1-5, characterized in that, The high-melting-point solids include TiC, MgAl2O4 and CaTiO3, and the mass percentage content of TiC is ≥35%.

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