Short-term shutdown recovery method for titanium slag electric furnace
Through precise feeding and power supply control before and after short-term shutdown of the titanium slag electric furnace, the solidification amount of slag iron is reduced, the problem of long recovery time and high cost of the electric furnace is solved, and efficient production recovery is achieved.
Patent Information
- Application Number
- CN202411554185.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-01
- Publication Date
- 2025-01-21
AI Technical Summary
After the titanium slag electric furnace is shut down for a short period of time, the slag iron in the furnace is prone to solidification, resulting in increased power consumption during the electric furnace recovery, difficulty in discharge, and long recovery time, resulting in problems such as lower output and increased production costs.
Through 75%to 85%of the titanium residue before stopping the oven, decide whether to discharge iron water after the discorting time, and add the preset reducing agent after the oven. Restore, accurate control of feeding and power supply systems.
It effectively reduces the solidification amount of slag iron during furnace shutdown, shortens the recovery time of the electric furnace, reduces recovery costs, and improves production efficiency and product quality.
Smart Images
Figure CN119332114A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of titanium slag production, and in particular to a method for restoring a titanium slag electric furnace after short-term shutdown. Background Art
[0002] Titanium slag electric furnace is a kind of equipment used to produce high-titanium slag. It mainly reduces the iron oxide in ilmenite into metallic iron through high-temperature reduction smelting process, and enriches titanium oxide in slag. The ilmenite concentrate is subjected to high-temperature reduction smelting in an electric furnace with a carbonaceous reducing agent. The iron oxide is selectively reduced to metallic iron, and titanium oxide is enriched in the slag to become titanium slag. This process is one of the methods for preparing titanium-rich materials. The TiO 2 The total amount exceeds 75%, and contains a small amount of oxide impurities such as iron, calcium, magnesium, silicon, aluminum, manganese and vanadium. This method can simultaneously recover the two main elements of titanium and iron in ilmenite, without generating waste in the process, and the furnace gas can be recycled or treated to meet the emission standards.
[0003] During the production process of titanium slag electric furnace, the electric furnace often needs to be shut down for a short period of time (10~48h) due to various reasons. During the shutdown process, improper operation and arbitrariness often lead to solidification of slag iron in the furnace. During the recovery process, power consumption increases, unloading is difficult, and the recovery time is long, which leads to reduced output and increased production costs. Summary of the invention
[0004] Numerical simulation analysis and actual measurement of the solidification state of slag and iron in the furnace during shutdown show that the heat dissipation below the electric furnace molten pool is slow during short-term shutdown. If appropriate insulation measures are taken, the heat loss of the slag layer and molten iron between the slag and iron mouths can be effectively reduced to avoid solidification, which is conducive to the rapid resumption of electric furnace operation and smooth slag and iron tapping.
[0005] In view of this, the present invention proposes a short-term shutdown recovery method for a titanium slag electric furnace, which is suitable for short-term shutdown of medium and large titanium slag electric furnaces above 12MVA.
[0006] A titanium slag electric furnace short-term shutdown recovery method of the present invention comprises the following steps: S100, produces titanium slag before stopping the furnace, and controls 75%~85% of the total titanium slag to be discharged from the furnace; S200, judging whether molten iron generated when producing titanium slag is discharged based on the furnace shutdown time; S300, after the furnace is discharged, a preset amount of reducing agent is added to the electric furnace, and then the furnace is stopped; S400, after the shutdown, the heating is first resumed by electrode roasting, and then the heating is resumed by an electric furnace. During the process of resuming heating, titanium concentrate and reducing agent are added to produce titanium slag.
[0007] In some embodiments, in step S100, producing titanium slag includes: S101, raw material addition: titanium concentrate and reducing agent mixed in a preset ratio are added to the electric furnace by continuous feeding, wherein the added weight of the titanium concentrate is 3 to 4 times the installed power of the electric furnace.
[0008] S102, reduction control: start the electric furnace to reduce the titanium concentrate under the action of the reducing agent to generate metallic iron liquid and slag enriched with titanium oxide.
[0009] In some embodiments, step S200 includes: If the shutdown time is between 10 and 24 hours, all the molten iron produced will be discharged; If the shutdown time is between 24 and 48 hours, the molten iron will not be discharged.
[0010] In some embodiments, in step S100, the amount of electricity delivered to the electric furnace is 1.25 to 1.35 times the weight of the titanium concentrate.
[0011] In some embodiments, in step S300, the amount of reducing agent added is 1 to 2 tons.
[0012] In some embodiments, in step S400, the electrode roasting method is used to resume heating, including: S410, control the electrode baking time to 0.25~0.35 times the furnace shutdown time, and control the electrode power supply power to gradually increase from 0.2 times to 0.4 times the furnace installed power; S411, adding a preset ratio of titanium concentrate and reducing agent into the electric furnace at one time. The amount of titanium concentrate added is 0.5-0.8 times the installed power of the electric furnace; S412, when the electrode power delivery reaches 1.45-1.55 times the amount of titanium concentrate added, step S411 is repeated until the electrode roasting is completed.
[0013] In some embodiments, in step S410, the duration of controlling the electrode power supply to operate at 0.2 times, 0.25 times, 0.3 times, and 0.4 times the installed power of the electric furnace is 1 / 4 of the total electrode roasting time.
[0014] In some embodiments, in step S400, using an electric furnace to resume heating includes: S420, start the electric furnace, and control the electric furnace to continuously supply power at a power supply of 0.6 times the installed power of the electric furnace until the amount of the total amount of titanium concentrate added during the electrode roasting is 1.45 to 1.55 times; S421, adding a preset ratio of titanium concentrate and a reducing agent into the electric furnace, and stopping the addition when the total amount of titanium concentrate reaches 0.75 to 0.85 times the weight of the titanium concentrate added in S101; S422, when the total amount of electricity delivered reaches 1.2~1.5 times the weight of the titanium concentrate added in S101, the furnace is taken out of the furnace at the appropriate time.
[0015] In some embodiments, in step S421, a preset ratio of titanium concentrate and a reducing agent are added to the electric furnace continuously or in batches.
[0016] In some embodiments, the reducing agent includes one or more of activated carbon, lignite, anthracite and petroleum coke; the preset ratio of titanium concentrate and reducing agent added each time is 10:0.9~1.2 by weight.
[0017] The beneficial effects of the present invention are as follows: the present invention mainly reduces the solidification amount of slag iron in the furnace during the shutdown period by controlling the charging, power supply and furnace discharge system before and after the shutdown, effectively shortens the recovery time of the electric furnace and reduces the recovery cost. It has the characteristics of simple operation and high production efficiency, and has a great guiding role in the short-term shutdown and recovery of titanium slag electric furnaces. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other embodiments can be obtained based on these drawings without paying creative work.
[0019] Figure 1 A schematic flow chart of a method for restoring a titanium slag electric furnace after a short-term shutdown is provided as an embodiment of the present invention. DETAILED DESCRIPTION
[0020] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the embodiments of the present invention are further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.
[0021] The present invention provides a short-term shutdown recovery method for a titanium slag electric furnace, which is suitable for short-term shutdown of medium and large titanium slag electric furnaces above 12MVA. The short-term shutdown recovery method for a titanium slag electric furnace of the present invention comprises the following steps: S100, produces titanium slag before stopping the furnace, and controls 75%~85% of the total titanium slag to be discharged from the furnace. That is to say, there is still about 20% titanium slag in the electric furnace, ensuring that there is still a certain amount of residual titanium slag covering the surface of the molten pool after the slag is discharged. By leaving a part of the titanium slag when slag is discharged, the residual titanium slag is covered on the surface of the molten pool to form a protective layer, reducing direct contact between air and the furnace lining, and preventing the furnace lining from being damaged by oxidation during the shutdown period. And titanium slag has good thermal insulation properties, which can slow down the rate of temperature drop in the furnace. During a short-term shutdown period, maintaining a certain temperature helps to quickly resume production when the furnace is reopened, shorten the heating time, and improve production efficiency.
[0022] S200, judging whether the molten iron generated when producing titanium slag is discharged based on the shutdown time. Specifically, if the shutdown time is short, the molten iron does not need to be completely discharged, because the molten iron will not solidify in a short time and can be retained in the furnace, reducing energy consumption and time when reheating. If the shutdown time is long, in order to ensure that the structure in the furnace is not damaged, the molten iron needs to be discharged to prevent it from solidifying during the shutdown period.
[0023] S300, after the furnace is discharged, a preset amount of reducing agent is added to the electric furnace, and then the furnace is shut down. The appropriate amount of reducing agent can maintain the chemical balance in the furnace, preventing the remaining titanium slag and molten iron from oxidizing or undergoing other adverse chemical reactions during the shutdown period. At the same time, this also helps to restore the electric furnace to normal working conditions faster when it is started next time, thereby improving production efficiency.
[0024] S400, after the shutdown is completed, the electrode roasting method is first used to resume heating, and then the electric furnace is used to resume heating, and titanium concentrate and reducing agent are added during the heating process to produce titanium slag. This application first uses electrode roasting to preheat the electric furnace, which helps to heat evenly and reduce thermal stress, and avoid damage to the electric furnace due to rapid temperature changes. Subsequently, the heating system of the electric furnace itself is used for comprehensive heating, and titanium concentrate and reducing agent are added to start a new round of production. It can ensure that the electric furnace can smoothly and efficiently return to normal production after shutdown.
[0025] Compared with the prior art, the present invention mainly reduces the solidification amount of slag iron in the furnace during the shutdown period by controlling the charging, power supply and furnace discharge system before and after the shutdown, effectively shortens the recovery time of the electric furnace and reduces the recovery cost. It has the characteristics of simple operation and high production efficiency, and has a great guiding role in the short-term shutdown and recovery of titanium slag electric furnaces.
[0026] In some embodiments, in step S100, producing titanium slag includes: S101, raw material addition: titanium concentrate and reducing agent mixed in a preset ratio are added to the electric furnace by continuous feeding, wherein the added weight of titanium concentrate is 3~4 times the installed power of the electric furnace to ensure that the electric furnace can operate in the best state while avoiding overload or waste of resources. Specifically, m represents the added weight of titanium concentrate (unit "t"), and P represents the installed power value of the electric furnace (unit "MVA"), then m=(3~4)P.
[0027] S102, reduction control: turning on the electric furnace, which heats the molten pool, so that the titanium concentrate is reduced to generate metallic iron and slag enriched with titanium oxide under the action of the reducing agent.
[0028] In some embodiments, step S200 includes: If the furnace is shut down for 10 to 24 hours, all the molten iron produced will be discharged; during this period, although the furnace is shut down for a short time, in order to reduce the burden when the furnace is reopened and to prevent the molten iron from solidifying in the furnace, the molten iron needs to be discharged in time. This can keep the furnace clean and facilitate subsequent operations.
[0029] If the shutdown time is between 24 and 48 hours, the molten iron will not be drained. Due to the long shutdown time, the molten iron will gradually cool down in the furnace and may partially solidify. If the iron is forced to be drained, it may cause damage to the furnace structure or affect the stability of the furnace lining. Therefore, it is chosen not to drain the molten iron, but to maintain the furnace temperature and prevent further solidification through other means (such as insulation measures).
[0030] In some embodiments, in step S100, the amount of electricity delivered to the electric furnace is 1.25 to 1.35 times the weight of the titanium concentrate. Specifically, Q represents the amount of electricity delivered to the electric furnace (unit: "MWh"), then Q = (1.25 to 1.35) m. The ratio of the amount of electricity delivered to the electric furnace to the weight of the titanium concentrate is directly related to the temperature and heat supply in the furnace. Sufficient heat can ensure that the reducing agent and the titanium concentrate fully react.
[0031] In some embodiments, in step S300, the amount of reducing agent added is 1-2 tons to maintain the chemical balance in the furnace.
[0032] In some embodiments, in step S400, the electrode roasting method is used to resume heating, including: S410, control the electrode baking time to 0.25~0.35 times the shutdown time, ensuring the heat supply during the recovery period matches the shutdown time. Control the electrode power supply to gradually increase from 0.2 times to 0.4 times the installed power of the electric furnace, that is, the power supply power in this stage gradually increases from 0.2P to 0.4P, which helps prevent sudden temperature changes in the electric furnace and reduce the impact on the furnace lining and the molten pool.
[0033] S411, adding a preset ratio of titanium concentrate and reducing agent into the electric furnace at one time, wherein the amount of titanium concentrate added is 0.5-0.8 times the installed power of the electric furnace; 1 represents the weight of titanium concentrate added to the furnace at one time, then m 1 =(0.5~0.8)P.
[0034] S412, when the electrode power delivery reaches 1.45~1.55 times the amount of titanium concentrate added at one time (i.e. (1.45~1.55)m 1 ), repeat step S411 until the electrode baking is completed. This cyclic feeding method can maintain continuous reaction in the electric furnace and ensure production efficiency and product quality.
[0035] In some embodiments, in step S410, the duration of controlling the electrode power to operate at 0.2 times, 0.25 times, 0.3 times, and 0.4 times (i.e., 0.2P, 0.25P, 0.3P, and 0.4P) the installed power of the electric furnace is 1 / 4 of the total electrode roasting time, so as to ensure uniform heat distribution during the entire roasting process, which is beneficial to improving production efficiency and product quality.
[0036] In some embodiments, in step S400, using an electric furnace to resume heating includes: S420, start the electric furnace, and control the electric furnace to continuously supply power at a power of 0.6 times (i.e., 0.6P) of the installed power of the electric furnace until the amount of the added titanium concentrate during the electrode roasting is 1.45 to 1.55 times; S421, adding a preset ratio of titanium concentrate and a reducing agent to the electric furnace, and stopping the addition of materials when the total amount of titanium concentrate reaches 0.75-0.85 times (i.e. (0.75-0.85) P) of the added weight of the titanium concentrate in S101; specifically, for example, m z Indicates the slag amount, X indicates the TiO in the titanium concentrate 2 Y represents the percentage of TiO in the target titanium slag produced. 2 The percentage content of m z =0.83mX / Y, which is about 80% of the normal slag discharge.
[0037] S422: When the total amount of electricity delivered reaches 1.2~1.5 times the weight of the titanium concentrate added in S101 (i.e. (1.2~1.5) m3), observe the chemical conditions in the electric furnace and start to discharge the materials at the appropriate time.
[0038] Through the above-mentioned start-up and recovery process of the electric furnace, it is ensured that the required operating temperature can be quickly reached after restarting, while avoiding equipment damage or reduced production efficiency due to rapid temperature changes. By accurately controlling the power supply and the amount of raw materials added, the production process can be optimized and product quality and production efficiency can be improved.
[0039] In some embodiments, in step S421, a preset ratio of titanium concentrate and a reducing agent are added to the electric furnace continuously or in batches.
[0040] In some embodiments, the reducing agent includes one or more of activated carbon, lignite, anthracite and petroleum coke; the preset ratio of titanium concentrate and reducing agent added each time is 10:0.9~1.2 by weight.
[0041] A specific embodiment is provided below to help those skilled in the art better understand the present invention: A 25MVA titanium slag electric furnace is scheduled to shut down for 18 hours due to equipment maintenance. Before shutting down, a furnace of titanium slag is produced in a specific way. The furnace is added with titanium concentrate weight m = 3.5 × 25 = 87.5 tons (TiO in titanium concentrate 2 The percentage of TiO in the target titanium slag is 46%. 2 The percentage of 75%), 8 tons of reducing agent, the two are mixed evenly and added into the electric furnace by continuous feeding. When the furnace power supply reaches Q = 1.3 × 87.5 = 113.75MWh, slag discharge begins, and the slag discharge volume is m z =0.83×87.5×46%÷75%=44.54 tons. After the slag is discharged, it is confirmed through the observation door that there is still residual titanium slag covering the surface of the molten pool. After the slag is discharged, all the molten iron produced by the furnace is discharged. After the discharge is completed, 1.5 tons of coke is added to the furnace through three feeding points around the electrode and the furnace is shut down.
[0042] When power is restored after maintenance, the titanium concentrate weight m 1 =0.6×25=15 tons, 1.5 tons of reducing agent, after mixing evenly, add them into the electric furnace at one time, and then enter the electrode roasting stage. The total time of electrode roasting is controlled at 5 hours (about 0.28 times the shutdown time), of which the power transmission power is 5MW during 0~1.25h, 6.25MW during 1.25~2.5h, 7.5MW during 2.5~3.75h, and 10MW during 3.75~5h. During this period, when the power transmission reaches 15×1.5=22.5MWh, 15 tons of titanium concentrate and 1.5 tons of reducing agent mixture are added at one time.
[0043] After the electrode roasting time is over, the electric furnace is continuously powered with a power supply of 0.6×25=15MW until the total power supply reaches 30×1.5=45MWh. After that, the power supply is controlled at about 0.7×25=17.5MW, and the feeding is continued until the total amount of titanium concentrate reaches 0.8×87.5=70 tons, and then the feeding is stopped. When the total power supply reaches 1.3×87.5=113.75MWh, the furnace is observed to be well oxidized, and the furnace is started to be discharged, completing the entire shutdown and recovery process.
[0044] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0045] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.
Claims
1. A method for restoring a titanium slag electric furnace after a short-term shutdown, characterized in that: The following steps are involved: S100, produces titanium slag before stopping the furnace, and controls 75%~85% of the total titanium slag to be discharged from the furnace; S200, judging whether molten iron generated when producing titanium slag is discharged based on the furnace shutdown time; S300, after the furnace is discharged, a preset amount of reducing agent is added to the electric furnace, and then the furnace is stopped; S400, after the shutdown, the heating is first resumed by electrode roasting, and then the heating is resumed by an electric furnace, and titanium concentrate and reducing agent are added during the heating resumption process.
2. The titanium slag electric furnace short-term shutdown recovery method according to claim 1, characterized in that: In step S100, producing titanium slag includes: S101, adding raw materials: adding titanium concentrate and reducing agent mixed in a preset ratio into the electric furnace by continuous feeding, wherein the added weight of the titanium concentrate is 3 to 4 times the installed power of the electric furnace; S102, reduction control: start the electric furnace to reduce the titanium concentrate under the action of the reducing agent to generate metallic iron liquid and slag enriched with titanium oxide.
3. The titanium slag electric furnace short-term shutdown recovery method according to claim 1, characterized in that: Step S200 includes: If the shutdown time is between 10 and 24 hours, all the molten iron produced will be discharged; If the shutdown time is between 24 and 48 hours, the molten iron will not be discharged.
4. The titanium slag electric furnace short-term shutdown recovery method according to claim 2, characterized in that: In step S100, the amount of electricity delivered to the electric furnace is 1.25 to 1.35 times the weight of the titanium concentrate.
5. The titanium slag electric furnace short-term shutdown recovery method according to claim 2, characterized in that: In step S300, the amount of reducing agent added is 1 to 2 tons.
6. The titanium slag electric furnace short-term shutdown recovery method according to claim 2, characterized in that: In step S400, the electrode roasting method is used to resume heating, including: S410, controlling the electrode baking time to be 0.25 to 0.35 times the furnace shutdown time, and controlling the electrode power supply to be gradually increased from 0.2 times to 0.4 times the installed power of the electric furnace; S411, adding a preset ratio of titanium concentrate and a reducing agent into the electric furnace at one time; the amount of titanium concentrate added is 0.5 to 0.8 times the installed power of the electric furnace; S412, when the electrode power delivery reaches 1.45-1.55 times the amount of titanium concentrate added, step S411 is repeated until the electrode roasting is completed.
7. The titanium slag electric furnace short-term shutdown recovery method according to claim 6, characterized in that: In step S410, the electrode power supply is controlled to operate at 0.2 times, 0.25 times, 0.3 times, and 0.4 times the installed power of the electric furnace, and the duration of each operation is 1 / 4 of the total electrode roasting time.
8. The titanium slag electric furnace short-term shutdown recovery method according to claim 2, characterized in that: In step S400, using an electric furnace to resume heating includes: S420, start the electric furnace, and control the electric furnace to continuously supply power at a power supply of 0.6 times the installed power of the electric furnace until the amount of the total amount of titanium concentrate added during the electrode roasting is 1.45 to 1.55 times; S421, adding a preset ratio of titanium concentrate and a reducing agent into the electric furnace, and stopping the addition when the total amount of the titanium concentrate reaches 0.75 to 0.85 times the added weight of the titanium concentrate described in S101; S422, when the total amount of electricity delivered reaches 1.2 to 1.5 times the weight of the titanium concentrate added in S101, the furnace is removed from the furnace at an appropriate time.
9. The titanium slag electric furnace short-term shutdown recovery method according to claim 8, characterized in that: In step S421, the preset ratio of titanium concentrate and reducing agent is added to the electric furnace continuously or in batches.
10. The method for restoring a titanium slag electric furnace from short-term shutdown according to any one of claims 1, 6, 8 or 9, characterized in that: The reducing agent includes one or more of activated carbon, blue carbon, anthracite and petroleum coke; the preset ratio of the titanium concentrate and the reducing agent added each time is 10:0.9~1.2 by weight.