Method for smelting carbide slag by using electric furnace

Abstract

The invention discloses a method for smelting carbide slag by using an electric furnace, which comprises the following steps: hot blast furnace slag is poured into the electric furnace, and the electric furnace comprises a furnace bottom with a concave structure with a wide upper part and a narrow lower part; hot blast furnace slag is pre-smelted in an electric furnace until a layer of semi-molten titanium carbide slag without fluidity is solidified in the downwards-concave structure of the furnace bottom, and the height of the solidified titanium carbide slag is lower than the lower edge position of a slag outlet of the electric furnace; and hot blast furnace slag and a carbonaceous reducing agent are added into the electric furnace for normal smelting, and liquid titanium carbide slag is obtained. According to the scheme provided by the invention, the titanium carbide slag serving as a target product is solidified in the concave structure of the furnace bottom to form the permanent furnace bottom, so that the service life of the furnace bottom is greatly prolonged, the frequency of dismantling and rebuilding the furnace bottom bricks is reduced, the production efficiency can be improved, and the consumption of refractory materials can be reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of smelting, in particular to a method for smelting carbonized slag by using an electric furnace. BACKGROUND

[0002] The high-temperature carbonization process of titanium-containing blast furnace slag is to take liquid titanium-containing blast furnace slag and carbonaceous reducing agent as raw materials, take a three-phase alternating current furnace as a reaction container, and obtain liquid carbonized slag through a reduction carbonization reaction. When the smelting endpoint is reached, the finished liquid carbonized slag flows out from a slag outlet into a subsequent process.

[0003] In the smelting process of carbonized slag, the structural design of the electric furnace bottom has an important influence on the smelting efficiency, the service life of the furnace bottom, and the production cost. At present, the carbonized slag smelting electric furnace adopts a flat bottom design. High-temperature molten slag erosion and electrode arc thermal stress radiation can accelerate the erosion of the refractory material of the furnace bottom, resulting in a short service life, usually about 1000 heats, and the furnace bottom bricks need to be removed and re-laid, which not only consumes a large amount of manpower and material resources, but also affects the production progress due to frequent furnace shutdown for maintenance. SUMMARY

[0004] Therefore, in order to overcome at least one aspect of the above problems, the embodiments of the present application also provide a method for smelting carbonized slag by using an electric furnace, comprising the steps of: turning hot blast furnace slag into the electric furnace, wherein the electric furnace comprises a furnace bottom with a lower concave structure having an upper wide and a lower narrow; carrying out pre-smelting in the electric furnace by using the hot blast furnace slag until a layer of semi-molten and non-flowable titanium carbide slag is solidified in the lower concave structure of the furnace bottom, and the height of the solidified titanium carbide slag is lower than the lower edge position of the slag outlet of the electric furnace; adding hot blast furnace slag and carbonaceous reducing agent into the electric furnace to carry out normal smelting to obtain liquid titanium carbide slag.

[0005] In some embodiments, the method further comprises: In the normal smelting stage, if the height of the titanium carbide slag solidified in the lower concave structure exceeds the upper edge position of the slag outlet, pre-smelting is continued until the height of the solidified titanium carbide slag is lower than the lower edge position of the slag outlet.

[0006] In some embodiments, if the height of the titanium carbide slag solidified in the lower concave structure exceeds the upper edge position of the slag outlet, pre-smelting is continued until the height of the solidified titanium carbide slag is lower than the lower edge position of the slag outlet, further comprising: If the height of the solidified titanium carbide slag in the lower concave structure exceeds the upper edge position of the slag outlet, normal smelting is stopped, and the hot state blast furnace slag is continuously turned into the electric furnace, and the electrode is continuously inserted into the hot state blast furnace slag for power supply, wherein the weight of the turned-in hot state blast furnace slag is controlled to be 1 / 2-1 of the weight of the hot state blast furnace slag turned in during the normal smelting stage, the input power of the electrode is controlled to be 1 / 4-1 / 2 of the rated power of the electric furnace, and the power supply time is controlled to be 5-10 h; Until the height of the solidified titanium carbide slag is lower than the lower edge position of the slag outlet, the normal smelting is continuously performed.

[0007] In some embodiments, the hot state blast furnace slag is used for pre-smelting in the electric furnace until a layer of semi-molten and non-flowable titanium carbide slag is solidified in the lower concave structure of the furnace bottom, and the height of the solidified titanium carbide slag is lower than the lower edge position of the slag outlet of the electric furnace, and the method further comprises: The hot state blast furnace slag is turned into the electric furnace so that the hot state blast furnace slag fills the lower concave structure and the liquid level of the hot state blast furnace slag is lower than the upper edge position of the slag outlet, and the carbonaceous reducing agent is added into the electric furnace, and the electrode is inserted into the hot state blast furnace slag for power supply; The hot state blast furnace slag is continuously turned into the electric furnace, the carbonaceous reducing agent is continuously added into the electric furnace, and the electrode is continuously inserted into the hot state blast furnace slag for power supply until a layer of semi-molten and non-flowable titanium carbide slag is solidified in the lower concave structure of the furnace bottom, and the height of the solidified titanium carbide slag is lower than the lower edge position of the slag outlet of the electric furnace.

[0008] In some embodiments, the hot state blast furnace slag is turned into the electric furnace so that the hot state blast furnace slag fills the lower concave structure and the liquid level of the hot state blast furnace slag is lower than the upper edge position of the slag outlet, and the carbonaceous reducing agent is added into the electric furnace, and the electrode is inserted into the hot state blast furnace slag for power supply, and the method further comprises: The amount of the carbonaceous reducing agent is controlled to be 20-25% of the weight of the hot state blast furnace slag.

[0009] In some embodiments, the method further comprises: The input power of the electrode is controlled to be 1 / 6-1 / 3 of the rated power of the electric furnace, and the power supply time is controlled to be 10-15 h.

[0010] In some embodiments, the hot state blast furnace slag is continuously turned into the electric furnace, and the carbonaceous reducing agent is continuously added into the electric furnace, and the electrode is continuously inserted into the hot state blast furnace slag for power supply, and the method further comprises: The weight of the hot state blast furnace slag continuously turned into the electric furnace is controlled to be 1 / 2-1 of the weight of the hot state blast furnace slag turned in during the normal smelting stage. The weight of the carbonaceous reducing agent continuously added into the electric furnace is controlled to be 15-20% of the weight of the hot blast furnace slag continuously poured into the electric furnace.

[0011] In some embodiments, the method further comprises: The input power of the electrode is controlled to be 1 / 4-1 / 2 of the rated power of the electric furnace, and the power-on time is controlled to be 5-10h.

[0012] In some embodiments, the process of continuously pouring the hot blast furnace slag into the electric furnace, continuously adding the carbonaceous reducing agent into the electric furnace, and continuously inserting the electrode into the hot blast furnace slag for power-on is repeated for 1-4 times. The process of continuously pouring the hot blast furnace slag into the electric furnace, continuously adding the carbonaceous reducing agent into the electric furnace, and continuously inserting the electrode into the hot blast furnace slag for power-on is repeated for 1-4 times.

[0013] In some embodiments, the process of normal smelting to obtain liquid titanium carbide slag by adding hot blast furnace slag and carbonaceous reducing agent into the electric furnace further comprises: The amount of the carbonaceous reducing agent is controlled to be 11-16% of the weight of the hot blast furnace slag, and the input power of the electrode is controlled to be 1 / 2-1 of the rated power of the electric furnace, and the power-on time of the electrode is controlled to be 3-6h.

[0014] The present application has one of the following beneficial technical effects: The scheme of the present application controls the reaction rate and residence time before the titanium carbide slag electric furnace starts normal smelting, so that the titanium carbide slag fills the lower concave structure of the furnace bottom which is wide at the top and narrow at the bottom. The titanium carbide slag settled at the bottom has high hardness and is in a semi-molten state, which can resist slag erosion and arc radiation. By using the titanium carbide slag as the target product and solidifying it in the concave structure of the furnace bottom, a permanent furnace bottom is formed, which greatly improves the service life of the furnace bottom, reduces the frequency of furnace bottom brick removal and re-laying, improves production efficiency, and reduces refractory consumption. BRIEF DESCRIPTION OF DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and those skilled in the art can also obtain other embodiments according to these drawings without creative labor.

[0016] Figure 1A flowchart of a method for smelting carbonized slag by using an electric furnace is provided for an embodiment of the present application. Figure 2 A schematic diagram of a smelting electric furnace is provided for an embodiment of the present application. DETAILED DESCRIPTION

[0017] To make the objectives, technical solutions, and advantages of the present application clearer, further detailed descriptions of embodiments of the present application are provided below with reference to the accompanying drawings.

[0018] It should be noted that all the expressions of "first" and "second" in the embodiments of the present application are used to distinguish two same-named different entities or different parameters, and it can be seen that "first" and "second" are only for the convenience of description and should not be understood as a limitation on the embodiments of the present application, which will not be described one by one in subsequent embodiments.

[0019] According to one aspect of the present application, embodiments of the present application also provide a method for smelting carbonized slag by using an electric furnace, as shown in Figure 1 The method comprises the following steps: S1, pouring hot blast furnace slag into an electric furnace, wherein the electric furnace comprises a furnace bottom having a lower concave structure with a wide upper part and a narrow lower part; S2, pre-smelting in the electric furnace by using the hot blast furnace slag until a layer of semi-molten and non-flowable titanium carbide slag is solidified in the lower concave structure of the furnace bottom, and the height of the solidified titanium carbide slag is lower than the lower edge position of the slag outlet of the electric furnace; S3, adding hot blast furnace slag and carbonaceous reducing agent into the electric furnace for normal smelting to obtain liquid titanium carbide slag.

[0020] In some embodiments, the smelting bath temperature of the carbonized slag is above 1600℃, and the molten slag high-temperature erosion, erosion, and electrode arc radiation have a serious impact on the erosion and damage of the refractory material of the furnace bottom, resulting in a short service life, usually about 1000 heats, and the furnace bottom bricks need to be removed and rebricked.

[0021] During the removal of the furnace bottom bricks, it is found that the molten slag erosion and penetration mainly occur in the working layer of the furnace bottom, and the erosion is less at the edge of the furnace bottom and gradually increases towards the center, and the entire erosion site presents a bowl-shaped structure with a wide upper part and a narrow lower part. The most serious erosion occurs at the central part of the electric furnace, and the maximum erosion amount is 2-2.5 times that of the edge of the furnace bottom, and the molten slag has penetrated to the transition layer. The main reason is that the temperature of the smelting bath near the central part is high, and the electrode arc radiation is large, which easily causes local overheating of the bottom of this area, and the erosion of the refractory material is accelerated. The temperature of the molten slag near the edge of the furnace bottom is low, and the arc radiation is small, and the erosion of the refractory material is slow.

[0022] The scheme provided by the application controls the reaction rate and residence time before the titanium carbide slag electric furnace starts normal smelting, so that the titanium carbide slag fills the concave structure of the furnace bottom which is wide at the top and narrow at the bottom. The titanium carbide slag which is in a semi-molten state and has high hardness can resist slag erosion and arc radiation. The titanium carbide slag which is the target product is solidified in the concave structure of the furnace bottom and becomes a permanent furnace bottom, thereby greatly improving the service life of the furnace bottom, reducing the frequency of furnace bottom brick removal and re-laying, improving production efficiency, and reducing refractory consumption.

[0023] In some embodiments, as shown in Figure 2 The titanium carbide slag electric furnace can include a circular furnace bottom, a furnace wall 2 extending upward along the edge of the furnace bottom, and a furnace shell arranged outside the furnace bottom and the furnace wall, wherein the furnace bottom includes a concave structure 11 which is wide at the top and narrow at the bottom, and the center of the concave structure 11 is on the same vertical line as the center of the circular furnace bottom.

[0024] In some embodiments, the upper diameter of the concave structure 1 is 0.7-1 times the diameter of the furnace bottom, and the bottom diameter of the concave structure 1 is 0.3-0.5 times the diameter of the furnace bottom.

[0025] In some embodiments, the side wall of the concave structure 1 is a circular arc, and the circular arc is tangent to the upper diameter and the bottom diameter of the concave structure 1.

[0026] In some embodiments, the radius corresponding to the circular arc is 1-1.5 times the depth of the concave structure 1.

[0027] Specifically, as shown in Figure 2 The upper surface of the furnace bottom is arranged as a concave structure 1, and the center of the concave structure 1 is on the same vertical line as the center of the circular furnace bottom. The concave structure 1 is a bowl-shaped concave structure which is wide at the top and narrow at the bottom. The upper diameter D1 of the concave structure 1 is the diameter DC of the circle formed by the concave upper surface, and the bottom diameter D2 of the concave structure 1 is the diameter AB of the circle formed by the concave lower surface. The depth H of the concave structure 1 is the height difference between the center of the upper surface of the furnace bottom and the lowest point of the concave structure, that is, the height difference between DC and AB.

[0028] The diameter D of the circle of the furnace bottom is the inner diameter EF of the electric furnace, the ratio of the upper diameter D1 of the concave structure to the diameter D of the furnace bottom is 0.7-1, the ratio of the bottom diameter D2 of the concave structure to the diameter D of the furnace bottom is 0.3-0.5, and the ratio of the depth H of the concave structure to the thickness of the permanent layer 6 of the furnace bottom is 0.65-1.

[0029] The side wall of the concave structure of the furnace bottom body is a circular arc transition, as shown in Figure 2The ratio of the radius R of the side wall arc to the depth H of the concave structure is 1-1.5, and the side wall arc is tangent to the upper diameter and the bottom diameter.

[0030] In some embodiments, the furnace bottom is sequentially provided with a permanent layer 6, a transition layer 5 and a working layer 4 from bottom to top, wherein the concave structure 1 is arranged in the working layer 4.

[0031] The permanent layer 6 is built by high alumina or alumina-magnesia castable; the transition layer 5 is built by corundum spinel brick; and the working layer 4 is built by magnesia carbon brick.

[0032] In some embodiments, the depth of the concave structure 1 is 0.65-1 times the thickness of the working layer 4.

[0033] In some embodiments, the thickness ratio of the permanent layer 6, the transition layer 5 and the working layer 4 is 1:1:3.

[0034] Specifically, the furnace bottom can include a permanent layer 6, a transition layer 5 and a working layer 4 sequentially arranged from bottom to top; the permanent layer 6 is built by high alumina or alumina-magnesia castable; the transition layer 5 is built by corundum spinel brick; and the working layer 4 is built by magnesia carbon brick. The height ratio of the permanent layer 6, the transition layer 5 and the working layer 4 is about 1:1:3. The concave structure 1 can be arranged in the working layer 4, and the ratio of the depth H of the concave structure 1 to the thickness of the working layer 4 is 0.65-1. In this way, the edge of the working layer 4 is built by magnesia carbon brick, which can resist slag erosion and arc radiation; and the center is filled with titanium carbide slag with high titanium carbide content. On the one hand, the titanium carbide slag is the target product and does not affect the product quality; on the other hand, at this temperature, the titanium carbide slag is in a semi-molten state and has no fluidity, has small erosion on the furnace lining, and has high hardness and is solidified in the furnace bottom, which can resist high-temperature slag and electrode arc erosion, can become a permanent furnace bottom, greatly improves the service life of the furnace bottom, reduces the frequency of furnace bottom brick removal and re-laying, improves the production efficiency, and greatly reduces the consumption of manpower and material resources.

[0035] In some embodiments, an expansion joint is arranged between the furnace bottom and the furnace shell, and the expansion joint is filled with silicon carbide-carbonaceous ramming material.

[0036] Specifically, an expansion joint is arranged between the furnace bottom body and the furnace shell, and the expansion joint is filled with silicon carbide-carbonaceous ramming material to adapt to the thermal expansion and contraction of the furnace bottom in the high-temperature working state and prevent the furnace bottom structure from being damaged due to thermal stress.

[0037] In some embodiments, a slag outlet 3 is arranged on the furnace wall, the center line of the slag outlet 3 is higher than the horizontal height of the edge of the furnace bottom, and the height difference between the two is within a preset range.

[0038] Specifically, a slag outlet 3 is arranged on the furnace wall, the center line of the slag outlet 3 is higher than the horizontal level of the center of the furnace bottom, and the slag outlet 3 is arranged near the edge of the furnace bottom. When the smelting endpoint is reached, the finished liquid carbonized slag flows out from the slag outlet 3 into the subsequent process.

[0039] In some embodiments, the method further comprises: In the normal smelting stage, if the height of the solidified titanium carbide slag in the lower concave structure exceeds the upper edge position of the slag outlet, the pre-smelting is continued until the height of the solidified titanium carbide slag is lower than the lower edge position of the slag outlet.

[0040] In some embodiments, if the height of the solidified titanium carbide slag in the lower concave structure exceeds the upper edge position of the slag outlet, the pre-smelting is continued until the height of the solidified titanium carbide slag is lower than the lower edge position of the slag outlet, further comprising: If the height of the solidified titanium carbide slag in the lower concave structure exceeds the upper edge position of the slag outlet, the normal smelting is stopped, and the hot-state blast furnace slag is continuously turned into the electric furnace, the electrode is continuously inserted into the hot-state blast furnace slag for power supply, the weight of the turned-in hot-state blast furnace slag is controlled to be 1 / 2-1 of the weight of the turned-in hot-state blast furnace slag in the normal smelting stage, the input power of the electrode is controlled to be 1 / 4-1 / 2 of the rated power of the electric furnace, and the power supply time is controlled to be 5-10 h; The normal smelting is continued until the height of the solidified titanium carbide slag is lower than the lower edge position of the slag outlet.

[0041] In some embodiments, the hot-state blast furnace slag is used for pre-smelting in the electric furnace until a layer of semi-molten and non-flowable titanium carbide slag is solidified in the lower concave structure of the furnace bottom, and the height of the solidified titanium carbide slag is lower than the lower edge position of the slag outlet of the electric furnace, further comprising: The hot-state blast furnace slag is turned into the electric furnace so that the hot-state blast furnace slag fills the lower concave structure and the liquid level of the hot-state blast furnace slag is lower than the upper edge position of the slag outlet, the carbonaceous reducing agent is added into the electric furnace, and the electrode is inserted into the hot-state blast furnace slag for power supply; The hot-state blast furnace slag is continuously turned into the electric furnace, the carbonaceous reducing agent is continuously added into the electric furnace, and the electrode is continuously inserted into the hot-state blast furnace slag for power supply until a layer of semi-molten and non-flowable titanium carbide slag is solidified in the lower concave structure of the furnace bottom, and the height of the solidified titanium carbide slag is lower than the lower edge position of the slag outlet of the electric furnace.

[0042] In some embodiments, the hot blast furnace slag is turned into the electric furnace to fill the concave structure and the liquid level of the hot blast furnace slag is below the upper edge of the slag outlet, and the carbonaceous reducing agent is added into the electric furnace, and the electrode is inserted into the hot blast furnace slag to electrify, further comprising: The amount of the carbonaceous reducing agent is controlled to be 20-25% of the weight of the hot blast furnace slag.

[0043] In some embodiments, the method further comprises: The input power of the electrode is controlled to be 1 / 6-1 / 3 of the rated power of the electric furnace, and the electrifying time is controlled to be 10-15h.

[0044] In some embodiments, the hot blast furnace slag is continuously turned into the electric furnace, and the carbonaceous reducing agent is continuously added into the electric furnace, and the electrode is continuously inserted into the hot blast furnace slag to electrify, further comprising: The weight of the hot blast furnace slag continuously turned into the electric furnace is controlled to be 1 / 2-1 of the weight of the hot blast furnace slag turned into the electric furnace in the normal smelting stage. The weight of the carbonaceous reducing agent continuously added into the electric furnace is controlled to be 15-20% of the weight of the hot blast furnace slag continuously turned into the electric furnace.

[0045] In some embodiments, the method further comprises: The input power of the electrode is controlled to be 1 / 4-1 / 2 of the rated power of the electric furnace, and the electrifying time is controlled to be 5-10h.

[0046] In some embodiments, the hot blast furnace slag is continuously turned into the electric furnace, the carbonaceous reducing agent is continuously added into the electric furnace, and the electrode is continuously inserted into the hot blast furnace slag to electrify until a layer of semi-molten and non-flowable titanium carbide slag is solidified in the concave structure of the hearth, and the height of the solidified titanium carbide slag is below the lower edge of the slag outlet of the electric furnace, further comprising: The process of continuously turning the hot blast furnace slag into the electric furnace, continuously adding the carbonaceous reducing agent into the electric furnace, and continuously inserting the electrode into the hot blast furnace slag to electrify is repeated 1-4 times.

[0047] In some embodiments, the hot blast furnace slag and the carbonaceous reducing agent are added into the electric furnace for normal smelting to obtain liquid titanium carbide slag, further comprising: The amount of the carbonaceous reducing agent is controlled to be 11%-16% of the weight of the hot blast furnace slag, and the input power of the electrode is controlled to be 1 / 2-1 of the rated power of the electric furnace, and the electrifying time of the electrode is controlled to be 3-6h.

[0048] Embodiment 1 The rated power of the carbonization slag electric furnace is 25 MVA, and the furnace bottom diameter is 7100 mm. The furnace bottom consists of a permanent layer, a transition layer, and a working layer from bottom to top. The permanent layer is constructed of high-alumina or alumina-magnesia castable refractory, the transition layer is constructed of corundum spinel bricks, and the working layer is constructed of magnesia-carbon bricks. The heights of the permanent layer, transition layer, and working layer are 400 mm, 400 mm, and 1200 mm, respectively.

[0049] The shape and dimensions of the concave structure at the bottom of the furnace are as follows: upper diameter D1 is 7100mm; bottom diameter D2 is 2800mm; depth H is 1200mm; and arc radius R is 1800mm.

[0050] The specific steps for the first use of the carbonization slag electric furnace after it has been built and dried are as follows: (1) 85t of hot blast furnace slag was turned into the electric furnace and 21t of carbonaceous reducing agent was added.

[0051] (2) Insert the electrode into the molten pool and energize it. Control the electrode input power to 6-8MW and the energizing time to 10h.

[0052] (3) Continue to pour 30t of hot blast furnace slag into the electric furnace; (4) Continue to add 4.5t of carbonaceous reducing agent.

[0053] (5) Insert the electrode into the molten pool and energize it. Control the electrode input power to 10-12MW and the energizing time to 10h.

[0054] (6) Power off, slag discharge.

[0055] Repeat steps (3) to (5) twice.

[0056] After the above operations, the electric furnace enters the normal smelting stage. Specifically, 60t of hot blast furnace slag and 9.5t of carbonaceous reducing agent are added to the electric furnace. The electrodes are then inserted into the molten pool and smelted by electricity, with the electrode input power controlled at 20-25 MW and the energizing time at 6 hours. During the smelting process, the bottom of the electrodes is controlled to be no lower than the upper edge of the slag outlet.

[0057] If, during the normal smelting stage, the furnace bottom is found to rise above the upper edge of the slag outlet, execute steps (3), (5), and (6) above until the height of the solidified carbonized slag at the furnace bottom is lower than the lower edge of the slag outlet. Then continue into the normal smelting stage.

[0058] Example 2 In another embodiment of the present invention, the rated power of the carbonization slag electric furnace is 25 MVA, and the furnace bottom diameter is 7100 mm. The furnace bottom includes a permanent layer, a transition layer, and a working layer from bottom to top. The permanent layer is constructed of high-alumina or alumina-magnesia castable, the transition layer is constructed of corundum spinel bricks, and the working layer is constructed of magnesia-carbon bricks. The heights of the permanent layer, the transition layer, and the working layer are 400 mm, 400 mm, and 1200 mm, respectively.

[0059] The shape and dimensions of the concave structure at the bottom of the furnace are as follows: upper diameter D1 is 6400mm; bottom diameter D2 is 2600mm; depth H is 1000mm; and radius of curvature R is 1250mm.

[0060] The specific steps for the first use of the carbonization slag electric furnace after it has been built and dried are as follows: (1) 65t of hot blast furnace slag was turned into the electric furnace and 14t of carbonaceous reducing agent was added.

[0061] (2) Insert the electrode into the molten pool and energize it. Control the electrode input power to be 5-7MW and the energizing time to be 13h.

[0062] (3) Continue to pour 45t of hot blast furnace slag into the electric furnace.

[0063] (4) Continue to add 8t of carbonaceous reducing agent.

[0064] (5) Insert the electrode into the molten pool and energize it. Control the electrode input power to be 8-10 MW and the energizing time to be 8h.

[0065] (6) Power off, slag discharge.

[0066] After the above operations, the electric furnace enters the normal smelting stage. Specifically, 60t of hot blast furnace slag and 7.8t of carbonaceous reducing agent are added to the electric furnace. The electrodes are then inserted into the molten pool and smelted by electricity. The electrode input power is controlled at 17-22 MW, and the energizing time is 4.5h. During the smelting process, the bottom of the electrodes is controlled to be no lower than the upper edge of the slag outlet.

[0067] If, during the normal smelting stage, the furnace bottom is found to rise above the upper edge of the slag outlet, execute steps (3), (5), and (6) above until the height of the solidified carbonized slag at the furnace bottom is lower than the lower edge of the slag outlet. Then continue into the normal smelting stage.

[0068] Example 3 In another embodiment of the present invention, the rated power of the carbonization slag electric furnace is 25 MVA, and the furnace bottom diameter is 7100 mm. The furnace bottom includes a permanent layer, a transition layer, and a working layer from bottom to top. The permanent layer is constructed of high-alumina or alumina-magnesia castable, the transition layer is constructed of corundum spinel bricks, and the working layer is constructed of magnesia-carbon bricks. The heights of the permanent layer, the transition layer, and the working layer are 400 mm, 400 mm, and 1200 mm, respectively.

[0069] The shape and dimensions of the concave structure at the bottom of the furnace are as follows: upper diameter D1 is 5300mm; bottom diameter D2 is 2500mm; depth H is 800mm; and arc radius R is 1200mm.

[0070] The specific steps for the first use of the carbonization slag electric furnace after it has been built and dried are as follows: (1) Pour 50t of hot blast furnace slag into the electric furnace and add 10t of carbonaceous reducing agent.

[0071] (2) Insert the electrode into the molten pool and energize it. Control the electrode input power to be 4-6MW and the energizing time to be 10h.

[0072] (3) Continue to pour 60t of hot blast furnace slag into the electric furnace; (4) Add 12t of carbonaceous reducing agent.

[0073] (5) Insert the electrode into the molten pool and energize it. Control the electrode input power to 6-8 MW and the energizing time to 5h.

[0074] (6) Power off, slag discharge.

[0075] Repeat steps (3) to (5) above for 4 furnace cycles.

[0076] After the above operations, the electric furnace enters the normal smelting stage, which specifically includes adding 60t of hot blast furnace slag and 6.6t of carbonaceous reducing agent into the electric furnace, inserting the electrodes into the molten pool and energizing, controlling the electrode input power at 13-18 MW, and energizing for 3 hours. During the smelting process, the bottom of the electrodes is controlled to be no lower than the upper edge of the slag outlet.

[0077] If, during the normal smelting stage, the furnace bottom is found to rise above the upper edge of the slag outlet, execute steps (3), (5), and (6) above until the height of the solidified carbonized slag at the furnace bottom is lower than the lower edge of the slag outlet. Then continue into the normal smelting stage.

[0078] By adopting the furnace bottom structure and filling titanium carbide slag as a permanent furnace bottom in the above embodiments, the service life of the furnace bottom is greatly extended. At the end of each furnace cycle, the refractory material of the furnace wall only needs to be replaced, and the furnace bottom does not need to be dismantled and rebuilt. The service life of the furnace bottom can reach more than 5,000 heat cycles, which not only shortens the maintenance time, but also reduces the consumption of refractory materials, saves production costs, and creates better conditions for smelting of carbon slag.

[0079] The above are exemplary embodiments disclosed in this invention. However, it should be noted that various changes and modifications can be made without departing from the scope of the embodiments of this invention as defined by the claims. The functions, steps, and / or actions of the methods according to the disclosed embodiments described herein do not need to be performed in any particular order. Furthermore, although the elements disclosed in the embodiments of this invention may be described or claimed individually, they may be understood as multiple unless explicitly limited to a singular number.

[0080] It should be understood that, as used herein, the singular form “a” is intended to include the plural form as well, unless the context clearly supports an exception. It should also be understood that, as used herein, “and / or” refers to any and all possible combinations of one or more of the associated listed items.

[0081] The embodiment numbers disclosed in the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0082] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention (including the claims) is limited to these examples. Within the framework of the invention, technical features of the above embodiments or different embodiments can be combined, and many other variations of different aspects of the invention exist, which are not provided in the details for the sake of brevity. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the invention should be included within the protection scope of the invention.

Claims

1. A method for smelting carbide slag using an electric furnace, characterized in that, include: Hot blast furnace slag is turned into the electric furnace, wherein the electric furnace includes a furnace bottom with a concave structure that is wider at the top and narrower at the bottom; Hot blast furnace slag is pre-smelted in an electric furnace until a layer of semi-molten and non-flowable titanium carbide slag is solidified in the concave structure at the bottom of the furnace, and the height of the solidified titanium carbide slag is lower than the lower edge of the slag outlet of the electric furnace. Hot blast furnace slag and carbonaceous reducing agent are added to the electric furnace and smelted normally to obtain liquid titanium carbide slag.

2. The method as described in claim 1, characterized in that, Also includes: During the normal smelting stage, if the height of the titanium carbide slag solidified in the concave structure exceeds the upper edge of the slag outlet, pre-smelting continues until the height of the solidified titanium carbide slag is lower than the lower edge of the slag outlet.

3. The method as described in claim 2, characterized in that, If the height of the titanium carbide slag solidified in the concave structure exceeds the upper edge of the slag outlet, pre-smelting continues until the height of the solidified titanium carbide slag is below the lower edge of the slag outlet, further including: If the height of the titanium carbide slag solidified in the concave structure exceeds the upper edge of the slag outlet, normal smelting is stopped, and the hot blast furnace slag is continued to be turned into the electric furnace. The electrode is then inserted into the hot blast furnace slag and energized. The weight of the hot blast furnace slag turned into the furnace is controlled to be 1 / 2 to 1 / 2 of the weight of the hot blast furnace slag turned into the furnace during the normal smelting stage. The input power of the electrode is controlled to be 1 / 4 to 1 / 2 of the rated power of the electric furnace, and the energizing time is controlled to be 5 to 10 hours. Normal smelting continues until the height of the solidified titanium carbide slag is lower than the lower edge of the slag outlet.

4. The method as described in claim 1, characterized in that, The process involves pre-smelting hot blast furnace slag in an electric furnace until a layer of semi-molten, non-flowable titanium carbide slag is solidified in the concave structure at the bottom of the furnace, with the height of the solidified titanium carbide slag below the lower edge of the slag outlet of the electric furnace. The process further includes: Hot blast furnace slag is poured into the electric furnace so that the hot blast furnace slag fills the concave structure and the liquid level of the hot blast furnace slag is lower than the upper edge of the slag outlet. Carbonaceous reducing agent is added into the electric furnace, and electrodes are inserted into the hot blast furnace slag and energized. Continue to pour the hot blast furnace slag into the electric furnace, continue to add the carbonaceous reducing agent into the electric furnace, and continue to insert the electrode into the hot blast furnace slag and apply electricity until a layer of semi-molten and non-flowing titanium carbide slag is solidified in the concave structure at the bottom of the furnace, and the height of the solidified titanium carbide slag is lower than the lower edge of the slag outlet of the electric furnace.

5. The method as described in claim 4, characterized in that, Hot blast furnace slag is introduced into the electric furnace to fill the concave structure, ensuring the liquid level of the hot blast furnace slag is below the upper edge of the slag outlet. A carbonaceous reducing agent is added to the electric furnace. Electrodes are inserted into the hot blast furnace slag and energized. The process further includes: The amount of carbonaceous reduction added is controlled to be 20-25% of the weight of the hot blast furnace slag.

6. The method as described in claim 5, characterized in that, Also includes: The input power of the electrode is controlled at 1 / 6 to 1 / 3 of the rated power of the electric furnace, and the energizing time is controlled at 10 to 15 hours.

7. The method as described in claim 4, characterized in that, The process further includes: continuing to pour the hot blast furnace slag into the electric furnace, continuing to add the carbonaceous reducing agent into the electric furnace, and continuing to insert the electrode into the hot blast furnace slag and apply electricity; The weight of the hot blast furnace slag that continues to be turned into the electric furnace is controlled to be 1 / 2 to 1 / 2 of the weight of the hot blast furnace slag turned into during the normal smelting stage; The weight of the carbonaceous reducing agent continuously added to the electric furnace is controlled to be 15-20% of the weight of the hot blast furnace slag continuously added to the electric furnace.

8. The method as described in claim 7, characterized in that, Also includes: The input power of the electrode is controlled at 1 / 4 to 1 / 2 of the rated power of the electric furnace, and the energizing time is controlled at 5 to 10 hours.

9. The method as described in claim 4, characterized in that, The hot blast furnace slag continues to be added into the electric furnace, the carbonaceous reducing agent continues to be added into the electric furnace, and the electrode continues to be inserted into the hot blast furnace slag and energized until a layer of semi-molten and non-flowable titanium carbide slag is solidified in the concave structure at the bottom of the furnace, and the height of the solidified titanium carbide slag is lower than the lower edge of the slag outlet of the electric furnace, further including: The process of continuously adding the hot blast furnace slag into the electric furnace, continuously adding the carbonaceous reducing agent into the electric furnace, and continuously inserting the electrode into the hot blast furnace slag and applying electricity is repeated 1-4 times.

10. The method as described in claim 3, characterized in that, Hot blast furnace slag and carbonaceous reducing agent are added to the electric furnace for normal smelting to obtain liquid titanium carbide slag, which further includes: The amount of carbonaceous reducing agent added is controlled to be 11% to 16% of the weight of the hot blast furnace slag, and the input power of the electrode is controlled to be 1 / 2 to 1 of the rated power of the electric furnace, and the energizing time of the electrode is controlled to be 3 to 6 hours.

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