Method for quickly removing molten carbonization slag and method for smelting titanium-containing blast furnace slag

Abstract

The application belongs to the field of metallurgy, and particularly discloses a molten carbonized slag rapid tapping method and a titanium-containing blast furnace slag smelting method. The molten carbonized slag rapid tapping method comprises the following steps: during the tapping process, nitrogen is directionally sprayed into the furnace in the direction of the slag tapping opening. The titanium-containing blast furnace slag smelting method comprises the following steps: S1: molten titanium-containing blast furnace slag and carbonaceous reducing agent are added into a carbonization electric furnace, and electric smelting is performed; S2: after the smelting is completed, the slag tapping operation is started, and in the first time period, electric power is not supplied, and after the first time period is completed, electric power is supplied at a low power, and nitrogen is directionally sprayed into the furnace in the direction of the slag tapping opening until the slag tapping is completed; and S3: the molten carbonized slag flowing out of the carbonization electric furnace is cooled and crushed to obtain finished carbonized slag with a proper particle size. Compared with the prior art, the method can effectively reduce the electric power consumption of the molten carbonized slag tapping, shorten the slag tapping time, and significantly optimize the production cost and production efficiency of the high-temperature carbonization process.

Description

Technical Field

[0001] This invention belongs to the field of metallurgy, specifically relating to a method for rapid slag removal from molten carbide slag and a method for smelting titanium-containing blast furnace slag. Background Technology

[0002] The Panxi region of my country possesses abundant vanadium-titanium magnetite resources, with proven titanium reserves of 870 million tons, accounting for 90.54% of my country's and 35.17% of the world's titanium reserves, respectively. Although my country has the world's largest titanium reserves, approximately 50% of these resources end up in high-titanium blast furnace slag during comprehensive utilization, resulting in a utilization rate of only 28% and a 40% dependence on imported titanium concentrate. Therefore, achieving the recovery of titanium resources from high-titanium blast furnace slag is of great significance for improving titanium resource utilization and ensuring resource supply security.

[0003] Currently, the relatively mature technology route for recovering titanium resources from high-titanium blast furnace slag is the "high-temperature carbonization-low-temperature chlorination" titanium extraction process. The process mainly involves: using titanium-containing blast furnace slag and carbonaceous reducing agents as raw materials, high-temperature melting in an AC electric furnace to obtain molten carbide slag; cooling and crushing the molten carbide slag to obtain finished carbide slag of suitable particle size; and then using the finished carbide slag in a low-temperature chlorination process to produce titanium dioxide.

[0004] High-titanium blast furnace slag, after carbonization, produces carbide slag containing solid TiC particles. This results in high viscosity, uneven slag discharge, and prolonged discharge time. To ensure smooth discharge, continuous power supply is required during the discharge stage to maintain the carbide slag temperature, reduce melt viscosity, and improve melt flowability. This leads to high power consumption during discharge, severely restricting production costs. Therefore, there is an urgent need to develop new methods for rapid discharge of molten carbide slag. Summary of the Invention

[0005] The present invention aims to solve the technical problems of high power consumption and low slag discharge efficiency in the existing molten carbonized slag discharge process, and provides a method for rapid slag discharge of molten carbonized slag to reduce power consumption during slag discharge, shorten slag discharge time, and optimize production costs and efficiency.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: According to a first aspect of the present invention, a method for rapid slag removal of molten carbonized slag is provided, comprising: directionally injecting nitrogen gas toward the slag outlet of the furnace during the slag removal process.

[0007] As a further implementation method, the nitrogen injection flow rate is 10m³ / h. 3 / h-40m 3 / h.

[0008] As a further implementation method, the nitrogen injection pressure is 0.3-0.6 MPa.

[0009] As a further implementation method, nitrogen injection begins 5-15 minutes after the start of the slag discharge operation and continues until the slag discharge is completed.

[0010] According to a second aspect of the present invention, a method for smelting titanium-containing blast furnace slag is provided, comprising the following steps: S1: Add molten titanium-containing blast furnace slag and carbonaceous reducing agent into a carburizing electric furnace and smelt it by power supply; S2: After smelting is completed, start the slag removal operation. During the first time period, power is temporarily not supplied. After the first time period ends, power is supplied at low power, and nitrogen is injected directionally towards the slag outlet in the furnace until the slag removal is completed. S3: Cool and crush the molten carbonized slag flowing out of the carbonization furnace to obtain finished carbonized slag with a suitable particle size.

[0011] As a further embodiment, in step S1, the mass of the carbonaceous reducing agent added is 10%-20% of the mass of the titanium-containing blast furnace slag.

[0012] As a further implementation, in step S1, the time for power-smelting is 1h-3h.

[0013] As a further implementation, in step S1, the power of the power-smelting process is 20-30MW.

[0014] As a further implementation, in step S2, the first time period is 5 min to 15 min.

[0015] As a further implementation, in step S2, the nitrogen injection flow rate is 10 m³ / s. 3 / h-40m 3 / h.

[0016] As a further embodiment, in step S2, the nitrogen injection pressure is 0.3-0.6 MPa.

[0017] As a further implementation, in step S2, the power supply after power restoration is 5-15MW.

[0018] As a further embodiment, in step S2, the nitrogen blowing time is 15 min to 30 min.

[0019] By adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art: During the slag removal process, nitrogen gas is directionally injected towards the slag outlet in the furnace to provide additional driving force for the slag removal process and accelerate slag discharge. At the same time, TiC in the carbide slag undergoes an exothermic reaction with N2 to generate TiN or Ti(C,N), which can supplement the reaction heat of the carbide slag melt and reduce the energy consumption of electric heating. In addition, the TiN or Ti(C,N) generated by the reaction can also undergo a chlorination reaction in the downstream low-temperature chlorination process to generate TiCl4, which can be further used to produce titanium dioxide or sponge titanium, thereby improving the recovery rate of titanium resources.

[0020] Compared with existing technologies, the method of the present invention can effectively reduce the power consumption of molten carbonized slag discharge, shorten the slag discharge time, and significantly optimize the production cost and efficiency of the high-temperature carbonization process. Attached Figure Description

[0021] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the description of the present invention will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other embodiments can be obtained based on these drawings without creative effort.

[0022] Figure 1 A flowchart of a titanium-containing blast furnace slag smelting method provided by the present invention. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0024] Specific embodiments of the invention are disclosed herein as needed; however, it should be understood that the embodiments disclosed herein are merely examples of the invention that may be implemented in various alternative forms. In the following description, various operating parameters and components are described in several contemplated embodiments. These specific parameters and components are provided as examples only and are not intended to be limiting.

[0025] The endpoints and any values ​​of the ranges disclosed in this invention are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this invention.

[0026] To address the technical problems of high power consumption and low slag discharge efficiency in the existing molten carbonized slag discharge process, this invention provides a method for rapid slag discharge of molten carbonized slag, so as to reduce power consumption during slag discharge, shorten slag discharge time, and optimize production costs and efficiency.

[0027] Based on the aforementioned objectives, the first aspect of this invention provides a method for rapid slag removal from molten carbide slag, comprising: during the slag removal process, directionally injecting nitrogen gas towards the slag outlet in the furnace. The directionally injected nitrogen gas generates aerodynamic thrust, directly propelling the high-viscosity carbide slag towards the slag outlet; simultaneously, the nitrogen gas undergoes an exothermic reaction with TiC in the molten slag, replenishing the heat of the slag body and reducing its viscosity, thereby achieving rapid slag removal and reducing power consumption.

[0028] In this invention, the directional injection of nitrogen towards the slag outlet in the furnace can be achieved by nitrogen nozzles installed on the furnace wall or furnace top. The nitrogen nozzles inject nitrogen directionally towards the slag outlet along the flow direction of the molten slag in the furnace. Through the dual effects of thrust and heat replenishment, rapid slag discharge and reduced power consumption are achieved.

[0029] For example, one to three high-temperature resistant nitrogen nozzles can be installed on the furnace wall or top opposite the slag outlet of the carbonization electric furnace; the nozzles are horizontal or tilted downwards, with their axis facing the center of the slag outlet, to ensure that the nitrogen jet flows along the direction of the molten slag in the furnace and blows directly to the slag outlet.

[0030] In some embodiments, nitrogen may be industrial pure nitrogen (purity ≥ 99.9%).

[0031] In some embodiments, the nitrogen injection flow rate can be 10 m³ / s. 3 / h-40m 3 / h. When the nitrogen injection flow rate is within this range, the gas volume is sufficient to propel the high-viscosity carbonized slag rapidly towards the slag outlet, and the heat release is stable, offsetting a small amount of heat dissipation and preventing excessive cold from being introduced; when the nitrogen injection flow rate is below 10m³ / h. 3 When the nitrogen flow rate is too low (e.g., 40 m³ / h), the thrust is insufficient, the TiC nitriding reaction is weak, the heat replenishment is inadequate, and the viscosity reduction effect is poor. 3 At a flow rate of [flow rate] / h, excessive nitrogen carries away a large amount of heat, causing the slag temperature to drop, viscosity to increase, slag discharge to slow down, and costs to rise. A typical, but not limited, nitrogen injection flow rate can be 10 m³ / h. 3 / h, 20m 3 / h, 30m 3 / h, 40m 3 / h.

[0032] In some embodiments, the nitrogen injection pressure can be 0.3-0.6 MPa. When the nitrogen injection pressure is within this range, it can penetrate the slag layer and reach the mainstream molten slag zone in the furnace, forming a stable directional thrust and simultaneously enhancing the TiC nitriding reaction. When the nitrogen injection pressure is less than 0.3 MPa, the jet is weak and has poor penetration; the nitrogen merely "floats" on the slag surface and cannot push the high-viscosity carbide slag, resulting in insufficient contact between TiC and N2 and weak heat replenishment. When the nitrogen injection pressure is higher than 0.6 MPa, the jet is too strong, which will splash high-temperature molten slag, posing a significant safety risk. Furthermore, it will excessively agitate the slag surface, introducing cold air, which will actually lower the temperature and increase viscosity, and will also waste nitrogen and increase costs. The nitrogen injection pressure is typically, but not limited to, 0.3 MPa, 0.4 MPa, 0.5 MPa, or 0.6 MPa. In some embodiments, nitrogen injection begins 5-15 minutes after the start of the slag removal operation and continues until the slag removal is completed. The present invention selects to start nitrogen injection 5-15 minutes after the start of slag removal operation because: in the early stage of slag removal, the molten slag temperature is high and the viscosity is low, and it can flow quickly by its own weight without additional energy consumption; after 5-15 minutes, the molten slag temperature drops, viscosity increases and flow rate slows down due to heat dissipation. At this time, starting the directional injection of nitrogen can provide flow driving force and supplement heat through TiC nitriding reaction, maintain the low viscosity of molten slag, achieve rapid slag removal and reduce power consumption.

[0033] Based on the same inventive concept, a second aspect of the present invention provides a method for smelting titanium-containing blast furnace slag, such as... Figure 1 As shown, it includes the following steps: S1: Add molten titanium-containing blast furnace slag and carbonaceous reducing agent into a carburizing electric furnace and smelt it by power supply; S2: After smelting is completed, start the slag removal operation. During the first time period, power is temporarily suspended. Power is restored after the first time period ends. At the same time, nitrogen gas is injected directionally towards the slag outlet in the furnace until the slag removal is completed. S3: Cool and crush the molten carbonized slag flowing out of the carbonization furnace to obtain finished carbonized slag with a suitable particle size.

[0034] In this invention, power is temporarily withheld during the initial slag discharge phase and restored later, with nitrogen injection significantly reducing electric heating energy consumption. Nitrogen injection provides additional driving force for slag discharge, accelerating the process. TiC reacts exothermically with N2 to generate TiN or Ti(C,N), replenishing the slag's heat, maintaining low viscosity and fluidity, and significantly shortening the slag discharge time. The generated TiN or Ti(C,N) can be further reacted in the low-temperature chlorination process to generate TiCl4, which can be used in the production of titanium dioxide or sponge titanium, improving the recovery rate of titanium resources.

[0035] In some embodiments, the mass of the carbonaceous reducing agent added is 10%-20% of the mass of the titanium-containing blast furnace slag. The mass of the carbonaceous reducing agent added is typically, but not limited to, 10%, 12%, 14%, 16%, 18%, or 20% of the mass of the titanium-containing blast furnace slag.

[0036] In some embodiments, the carbonaceous reducing agent is coke powder.

[0037] In some embodiments, the electro-smelting time in step S1 is 1-3 hours. The electro-smelting time can typically, but is not limited to, be 1 hour, 2 hours, or 3 hours.

[0038] In some embodiments, in step S1, the power supply for smelting is 20-30MW. The power supply for smelting is typically, but not limited to, 20MW, 25MW, or 30MW.

[0039] In some embodiments, in step S2, the first time period is 5 min to 15 min. The first time period can typically, but is not limited to, be 5 min, 7 min, 9 min, 11 min, 13 min, or 15 min. Before 5 min, the slag is still very hot, and nitrogen injection and power supply are unnecessary; after 15 min, the slag temperature is too low and the viscosity is too high, so even nitrogen injection will not be able to push it, and it is easy to clog the slag; 5-15 min is the optimal window for the fastest natural gravity flow and the most effective subsequent intervention.

[0040] In some embodiments, in step S2, the nitrogen injection flow rate is 10 m³ / s. 3 / h-40m 3 / h. When the nitrogen injection flow rate is within this range, the gas volume is sufficient to propel the high-viscosity carbonized slag rapidly towards the slag outlet, and the heat release is stable, offsetting a small amount of heat dissipation and preventing excessive cold from being introduced; when the nitrogen injection flow rate is below 10m³ / h. 3 When the nitrogen flow rate is too low (e.g., 40 m³ / h), the thrust is insufficient, the TiC nitriding reaction is weak, the heat replenishment is inadequate, and the viscosity reduction effect is poor. 3 At a flow rate of [flow rate] / h, excessive nitrogen carries away a large amount of heat, causing the slag temperature to drop, viscosity to increase, slag discharge to slow down, and costs to rise. A typical, but not limited, nitrogen injection flow rate can be 10 m³ / h. 3 / h, 20m 3 / h, 30m 3 / h, 40m 3 / h.

[0041] In some embodiments, in step S2, the nitrogen injection pressure is 0.3-0.6 MPa. When the nitrogen injection pressure is within this range, it can penetrate the slag layer and reach the mainstream molten slag zone in the furnace, forming a stable directional thrust and simultaneously enhancing the TiC nitriding reaction. When the nitrogen injection pressure is less than 0.3 MPa, the jet is weak and the penetration is poor; the nitrogen only "floats" on the slag surface and cannot push the high-viscosity carbide slag, resulting in insufficient contact between TiC and N2 and weak heat replenishment. When the nitrogen injection pressure is higher than 0.6 MPa, the jet is too strong and will splash high-temperature molten slag, posing a significant safety risk. In addition, it will excessively agitate the slag surface, introduce cold air, which will actually lower the temperature and increase viscosity, and will also cause nitrogen waste and increased costs. The nitrogen injection pressure can typically, but is not limited to, 0.3 MPa, 0.4 MPa, 0.5 MPa, or 0.6 MPa.

[0042] In some embodiments, in step S2, the power supply after power restoration is 5-15MW. The power supply at this stage is 40%-70% of the power supply at this stage in the prior art. Compared to the prior art, the present invention can effectively reduce the power consumption during slag removal in the high-titanium blast furnace slag carbonization smelting process, shorten the slag removal time, and significantly optimize the production cost and efficiency of the high-temperature carbonization process. The power supply after power restoration can typically, but is not limited to, be 5MW, 10MW, or 15MW.

[0043] In some embodiments, the nitrogen purging time in step S2 is 15 min to 30 min. The nitrogen purging time is typically, but not limited to, 15 min, 20 min, 25 min, or 30 min.

[0044] In some embodiments, the method is implemented as follows: (1) 40t-80t of molten high-titanium blast furnace slag and a certain proportion of coke powder (the proportion of coke powder is 10%-20% of the mass of high-titanium blast furnace slag) are smelted in a carburizing electric furnace for 1h-3h. After smelting, the slag is discharged and the molten slag flowing out of the electric furnace is cooled and crushed to obtain finished carburized slag of suitable particle size; (2) Power will not be supplied for 5-15 minutes after the slag removal operation starts. During this period, the molten slag temperature is high and the viscosity is low, ensuring smooth slag removal. Power will be restored after this period ends (power supply of 5-15MW), and power will be supplied in 10m increments. 3 / h-40m 3 N2 is injected towards the slag outlet at a flow rate of / h; (3) After spraying N2 for 15-30 minutes, the slag is discharged. The molten carbonized slag is cooled and crushed to obtain finished carbonized slag with appropriate particle size, which is used in the next low-temperature chlorination process to produce refined TiCl4, and further used to produce titanium dioxide or sponge titanium, etc.

[0045] The present invention will be further described in detail below with reference to specific embodiments.

[0046] Example 1: This embodiment was implemented in a factory, using a three-phase AC circular carbonization furnace. The specific steps are as follows: 50 tons of molten titanium-containing blast furnace slag (composition shown in Table 1) were added to the electric carbide furnace via a chute. Then, 10 tons of coke powder were added to the electric carbide furnace, and smelting was started with power supply at 25 MW. After smelting for 2 hours, slag was discharged. During the slag discharge process, the molten carbide slag was cooled and crushed to obtain finished carbide slag of suitable particle size.

[0047] Power is temporarily withheld for 15 minutes before slag discharge, during which time the molten slag temperature is high and the viscosity is low, ensuring smooth slag discharge. Power is restored 15 minutes after slag discharge, with a power output of 9MW, and then adjusted according to a 30m... 3 N2 is injected into the slag outlet at a flow rate of / h for a total of 20 minutes, after which slag discharge ends.

[0048] The total time for slag removal is 35 minutes, and the power consumption for slag removal is 3000 kWh.

[0049] Comparative Example 1: This comparative example uses the same equipment, raw materials, and smelting parameters as Example 1.

[0050] The specific steps for this comparative example are as follows: 50 tons of molten titanium-containing blast furnace slag (composition shown in Table 1) were added to the electric carbide furnace via a chute. Then, 10 tons of coke powder were added to the electric carbide furnace, and smelting was started with power supply at 25 MW. After smelting for 2 hours, slag was discharged. During the slag discharge process, the molten carbide slag was cooled and crushed to obtain finished carbide slag of suitable particle size.

[0051] Power is temporarily withheld for 15 minutes before slag discharge, during which time the molten slag temperature is high and the viscosity is low, ensuring smooth slag discharge. Power is restored 15 minutes after slag discharge, with a power output of 15MW, and slag discharge ends 40 minutes after power is supplied.

[0052] The total time for slag removal is 55 minutes, and the power consumption for slag removal is 10,000 kWh.

[0053] Compared with Comparative Example 1, Example 1 of the present invention shortens the slag discharge time by 20 minutes and reduces the slag discharge power consumption by 7000 kWh, significantly optimizing the production cost and efficiency of the high-temperature carbonization process.

[0054] Table 1. Main chemical components of high-titanium blast furnace slag (%)

[0055] In summary, the method provided by this invention utilizes nitrogen gas injected along the furnace towards the slag outlet during the slag removal process, providing additional driving force for the slag removal process. Simultaneously, the exothermic reaction between TiC and N2 in the carbonized slag generates TiN or Ti(C,N), which replenishes the reaction heat to the molten carbonized slag, reducing the energy consumption for electric heating. Furthermore, TiN or Ti(C,N) can undergo a chlorination reaction in the downstream low-temperature chlorination process to generate TiCl4, which can be further used in the production of titanium dioxide or sponge titanium. Compared to existing technologies, this invention effectively reduces the power consumption and shortens the slag removal time in the high-titanium blast furnace slag carbonization smelting process, significantly optimizes the production cost and efficiency of the high-temperature carbonization process, and has the potential for application in other slag smelting fields.

[0056] Finally, it should be noted that the embodiments described above are only some, not all, of the embodiments of the present invention. The detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

Claims

1. A method for rapid discharge of molten carbonized slag, characterized in that, include: During the slag removal process, nitrogen gas is injected directionally towards the slag outlet in the furnace.

2. The method for rapid slag removal from molten carbonized slag according to claim 1, characterized in that, Nitrogen injection flow rate is 10m³ 3 / h-40m 3 / h.

3. The method for rapid slag removal from molten carbonized slag according to claim 1, characterized in that, The nitrogen injection pressure is 0.3-0.6 MPa.

4. The method for rapid slag removal from molten carbonized slag according to claim 1, characterized in that, Nitrogen injection begins 5-15 minutes after the slag discharge operation starts and continues until the slag discharge is completed.

5. A method for smelting titanium-containing blast furnace slag, characterized in that, Includes the following steps: S1: Add molten titanium-containing blast furnace slag and carbonaceous reducing agent into a carburizing electric furnace and smelt it by power supply; S2: After smelting is completed, start the slag removal operation. During the first time period, power is temporarily suspended. Power is restored after the first time period ends. At the same time, nitrogen gas is injected directionally towards the slag outlet in the furnace until the slag removal is completed. S3: Cool and crush the molten carbonized slag flowing out of the carbonization furnace to obtain finished carbonized slag with a suitable particle size.

6. The method for smelting titanium-containing blast furnace slag according to claim 1, characterized in that, In step S1, the mass of the carbonaceous reducing agent added is 10%-20% of the mass of the titanium-containing blast furnace slag, the time for power transmission and smelting is 1h-3h, and the power of power transmission and smelting is 20-30MW.

7. The method for smelting titanium-containing blast furnace slag according to claim 1, characterized in that, In step S2, the first time period is 5 min to 15 min.

8. The method for smelting titanium-containing blast furnace slag according to claim 1, characterized in that, In step S2, the nitrogen injection flow rate is 10 m³ / s. 3 / h-40m 3 / h, nitrogen injection pressure is 0.3-0.6MPa.

9. The method for smelting titanium-containing blast furnace slag according to claim 1, characterized in that, In step S2, the power supply after power restoration is 5-15MW.

10. The method for smelting titanium-containing blast furnace slag according to claim 1, characterized in that, In step S2, the nitrogen blowing time is 15 min to 30 min.

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