Methods for rapid dismantling and restoration of titanium slag electric furnaces

Abstract

This invention discloses a method for rapidly dismantling and restoring a titanium slag electric furnace, comprising: setting an iron discharge port 300-800mm below the taphole of the electric furnace, and discharging molten iron from the furnace to the location of the iron discharge port; removing the refractory material above the iron discharge port, while retaining the original refractory material below the iron discharge port; cleaning the retained original refractory material and rebuilding the area above the iron discharge port with new refractory material; excavating a cavity in the slag below the electrodes, and refilling the cavity with furnace drying material for furnace drying. This invention can shorten the dismantling cycle, save costs, and also shorten the furnace drying time, achieving rapid resumption of production.

Description

Technical Field

[0001] This invention relates to the field of titanium slag electric furnace technology, and specifically to a method for rapidly dismantling and restoring a titanium slag electric furnace. Background Technology

[0002] Titanium slag electric arc furnaces are used to smelt ilmenite to obtain molten iron and titanium slag. After prolonged use, due to the high chemical reactivity of the molten slag at high temperatures, it easily corrodes the refractory materials of the furnace. Combined with the long-term effects of high temperatures and mechanical erosion, the refractory materials of the titanium slag electric arc furnace gradually dissolve and fall off, forming gaps between them. When high-temperature molten iron or slag passes through these gaps, it can cause iron or slag spillage accidents.

[0003] Traditional large titanium slag electric furnaces require major overhauls after reaching the end of their service life. The overhaul involves completely removing the furnace lining and rebuilding it. This method faces problems such as long dismantling period, high cost, and long baking time for the new titanium slag electric furnace (generally more than 120 days). Summary of the Invention

[0004] The main objective of this invention is to provide a method for the rapid dismantling and restoration of titanium slag electric furnaces, in order to solve the problems of long dismantling cycles and high costs of titanium slag electric furnaces and long baking times for new titanium slag electric furnaces in the prior art.

[0005] According to one aspect of the present invention, a method for rapidly dismantling and restoring a titanium slag electric furnace is provided, comprising:

[0006] A discharge port is installed 300-800mm below the tapping spout of the electric furnace, and the molten iron in the electric furnace is discharged to the discharge port.

[0007] Remove the refractory material above the iron discharge port, and retain the original refractory material below the iron discharge port;

[0008] The original refractory materials were cleaned up, and the area above the iron drain opening was rebuilt with new refractory materials.

[0009] Holes are dug in the slag below the electrodes, and the furnace drying material is refilled into the holes for furnace drying.

[0010] According to one embodiment of the present invention, the method further includes replacing the damaged refractory material near the iron discharge port.

[0011] According to one embodiment of the invention, before rebuilding with new refractory material, the method further includes: digging a trench between the furnace wall and the slag along the circumference of the furnace wall.

[0012] According to one embodiment of the present invention, the width of the trench is 30-50 mm and the depth is 500-1000 mm.

[0013] According to one embodiment of the present invention, when rebuilding with new refractory material, the multiple layers of refractory material are laid in a stepped manner towards the center of the electric furnace in an upward direction.

[0014] According to one embodiment of the present invention, the protrusion of each refractory layer relative to the adjacent refractory layer below does not exceed 10 mm.

[0015] According to one embodiment of the present invention, when rebuilding with new refractory material, a gap is reserved at the joint between the new refractory material and the original refractory material.

[0016] According to one embodiment of the present invention, the size of the gap is 2-3 mm.

[0017] According to one embodiment of the present invention, the method further includes: inserting a thermocouple at the junction of the new refractory material and the original refractory material; and controlling the heating rate of the thermocouple to not exceed 1°C / h during furnace baking.

[0018] According to one embodiment of the present invention, the insertion size of the thermocouple is 1 / 3 to 1 / 4 of the thickness of the refractory material; and / or the depth of the cavity is 500-1000 mm.

[0019] In the technical solution of this invention, the severely corroded refractory materials (refractory materials above the iron discharge port) inside the furnace are removed and rebuilt, while the less severely corroded refractory materials (refractory materials below the iron discharge port) are retained. This can shorten the removal cycle, save costs, and also shorten the furnace drying time, enabling rapid production recovery. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 A schematic diagram of a titanium slag electric furnace is shown during the implementation of a method for rapid dismantling and restoration of a titanium slag electric furnace according to an embodiment of the present invention.

[0022] Figure 2 Another schematic diagram of a titanium slag electric furnace is shown during the implementation of a method for rapid dismantling and restoration of a titanium slag electric furnace according to an embodiment of the present invention. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to specific examples and the accompanying drawings.

[0024] It should be noted that all uses of "first" and "second" in the embodiments of the present invention are for the purpose of distinguishing two entities or parameters with the same name but different names. It is clear that "first" and "second" are only for the convenience of expression and should not be construed as limiting the embodiments of the present invention. Subsequent embodiments will not explain this in detail.

[0025] A titanium slag electric arc furnace (EAF) refers to an electric furnace that smelts titanium slag from ilmenite. The furnace lining of an AAF is constructed of refractory materials (e.g., magnesia refractory bricks, high-alumina refractory bricks, or carbonaceous refractory bricks). Titanium slag production requires smelting at a high temperature of 1600–1800°C. Due to the extremely high chemical reactivity of molten titanium slag, it easily corrodes the furnace refractory materials. Combined with the long-term effects of high temperature and mechanical erosion, the refractory materials gradually dissolve and detach, creating gaps between them. High-temperature molten iron or slag passing through these gaps can cause molten iron or slag spills. As mentioned in the background section, existing technologies typically involve a complete overhaul of damaged AAFs. This method of completely removing and rebuilding the furnace lining is time-consuming, costly, and requires a long preheating time for the new AAF. To address this technical problem, this application proposes one or more embodiments as described below.

[0026] refer to Figure 1 and Figure 2 This invention proposes a method for rapidly dismantling and restoring a titanium slag electric furnace, comprising:

[0027] A discharge port is installed 300-800mm below the tapping spout of the electric furnace, and the molten iron in the electric furnace is discharged to the discharge port.

[0028] Remove the refractory material above the iron discharge port, and retain the original refractory material below the iron discharge port;

[0029] The original refractory materials were cleaned up, and the area above the iron drain opening was rebuilt with new refractory materials.

[0030] Holes are dug in the slag below the electrodes, and the furnace drying material is refilled into the holes for furnace drying.

[0031] In an embodiment of the invention, a discharge port is provided 300-800mm below the taphole of the electric furnace. This is because the inventors discovered that refractory material damage in titanium slag electric furnaces mainly occurs above this location. Therefore, this invention provides a taphole at this location to ensure that molten iron is discharged as much as possible. The refractory material can then be removed from top to bottom up to the discharge port, while the less damaged refractory material below the discharge port is retained. The area above the discharge port is then rebuilt with new refractory material. This shortens the dismantling cycle, saves costs, and also reduces furnace drying time, enabling rapid production recovery. In some embodiments, damaged refractory material near the discharge port can also be replaced.

[0032] Combination Figure 1 and Figure 2 In some implementations, before rebuilding with new refractory material, the method also includes digging a trench along the circumference of the furnace wall between the furnace wall and the slag. The trench can be dug around the entire furnace wall to form the required trench. By digging the trench, space is reserved for the expansion of the refractory material during subsequent furnace drying, preventing the slag from hindering the expansion of the refractory material and causing damage. Preferably, the width of the trench is 30-50 mm, and the depth is 500-1000 mm. It should be noted that the width of the trench refers to the dimension of the trench along the radial direction of the electric furnace, and the depth of the trench is the dimension of the trench along the axial direction (i.e., the height direction) of the electric furnace.

[0033] refer to Figure 2 In some implementations, when rebuilding with new refractory material, an inverted, stepped-out method is used. This causes multiple refractory material layers to extend in a stepped manner towards the center of the electric furnace from bottom to top (i.e., the upper refractory material layer extends towards the center of the electric furnace relative to the lower refractory material layer it is joined to). This results in a stepped increase in the thickness of the multiple refractory material layers (thickness represents the dimension along the radial direction of the electric furnace) from bottom to top, until the thickness of the refractory material layer reaches and remains at a predetermined thickness (the predetermined thickness can be the original thickness of the refractory material layer). In embodiments of the present invention, the new refractory material is built on top of the existing refractory material, which has been partially eroded and reduced in thickness. The inverted, stepped-out method described above is used to gradually increase the thickness of the newly built refractory material layers from bottom to top, thus gradually restoring the original thickness. Preferably, the extension dimension of each refractory material layer relative to the adjacent refractory material layer below does not exceed 10 mm to ensure the stability of the refractory material masonry.

[0034] In some embodiments, considering the linear expansion rate at the interface between new and old refractory materials, a gap is left at the joint between the new and existing refractory materials during reconstruction with new refractory materials. This prevents excessive compression and damage to the joint due to expansion. Preferably, the gap is 2-3 mm. This size corresponds to the amount of expansion at the joint between the new and old refractory materials, ensuring that the joint can fit tightly together after expansion, without being excessively compressed by the expansion or affecting the sealing performance.

[0035] In some embodiments, the method further includes: inserting a thermocouple at the junction of the new and existing refractory materials; and controlling the heating rate of the thermocouple to not exceed 1°C / h during furnace drying. The inventors recognized that the heating condition at the junction of the new and old refractory materials is particularly important, directly affecting the furnace drying effect. Therefore, a thermocouple is installed at this location to monitor the heating rate and ensure that the heating rate is not too fast. In some embodiments, the insertion size of the thermocouple is 1 / 3 to 1 / 4 of the refractory material thickness.

[0036] In some embodiments, the depth of the cavity dug under the electrode is 500-1000 mm. The furnace drying material can be added after the corresponding cavity is dug under each electrode.

[0037] The following description is based on specific embodiments.

[0038] Example 1

[0039] The specific methods for quickly dismantling and restoring titanium slag electric furnaces include the following steps:

[0040] (1) Set the iron discharge port in the furnace 300mm below the iron tap.

[0041] (2) Discharge the molten iron to the iron discharge port in one go.

[0042] (3) Remove the furnace bricks from top to bottom to the iron discharge port.

[0043] (4) After replacing the damaged refractory material near the iron discharge port, dig a trench 30mm wide and 500mm deep between the grate wall and the slag.

[0044] (5) After cleaning the surface of the original refractory material, rebuild the refractory material by using the inverted laying method, with the distance between each layer not exceeding 10mm.

[0045] (6) The linear expansion rate should be considered at the interface between new and old refractory materials, and a 2mm gap should be reserved.

[0046] (7) Install thermocouples at the interface between new and old refractory materials, with the thermocouples inserted at a distance of about 1 / 4 of the thickness of the refractory material.

[0047] (8) After digging a 500mm deep hole in the middle of each electrode, add the oven drying material again.

[0048] (9) The heating rate of newly added thermocouples during the oven baking period shall not exceed 1℃ / h.

[0049] Example 2

[0050] The specific methods for quickly dismantling and restoring titanium slag electric furnaces include the following steps:

[0051] (1) Set the iron discharge port in the furnace 800mm below the iron tap.

[0052] (2) Discharge the molten iron to the iron discharge port in one go.

[0053] (3) Remove the furnace bricks from top to bottom to the iron discharge port.

[0054] (4) After replacing the damaged refractory material near the iron discharge port, dig a trench 50mm wide and 1000mm deep between the grate wall and the slag.

[0055] (5) After cleaning the surface of the original refractory material, rebuild the refractory material by using the inverted laying method, with the distance between each layer not exceeding 10mm.

[0056] (6) The linear expansion rate should be considered at the interface between the new and old refractory materials, and a 3mm gap should be reserved.

[0057] (7) Install thermocouples at the interface between new and old refractory materials, with the thermocouples inserted at a distance of about 1 / 3 of the thickness of the refractory material.

[0058] (8) After digging a hole 1000mm deep in the middle of each electrode, add the oven drying material again.

[0059] (9) The heating rate of newly added thermocouples during the oven baking period shall not exceed 1℃ / h.

[0060] In Examples 1 and 2, the electric furnace can be dismantled and then restored to production in about 80 days. In contrast, the original overhaul method takes 120 days. Compared with the original overhaul method, Examples 1 and 2 can save about 40 days. Furthermore, no accidents such as molten iron leakage or molten iron running occurred within one year of the electric furnace being restored to production.

[0061] In summary, to address the issues of long dismantling cycles and high costs associated with titanium slag electric furnaces, this invention removes and rebuilds severely corroded refractory materials within the furnace. This not only shortens the repair cycle and reduces costs but also shortens the furnace recovery time, reducing dismantling, repair, and recovery time by more than 30%. Furthermore, this invention considers numerous details in the furnace repair process. By digging trenches along the circumference of the furnace wall between the furnace wall and the slag, it prevents the slag from hindering the expansion of the refractory materials and causing damage. By employing an inverted, platform-like construction method, it ensures the furnace wall is restored to its original thickness. By leaving gaps at the joints between the new and existing refractory materials, it prevents excessive compression and damage due to expansion. By inserting thermocouples at the joints between the new and existing refractory materials, it controls the heating rate during furnace drying, ensuring effective drying. Ultimately, this invention achieves rapid furnace repair while further guaranteeing repair quality, preventing accidents such as molten iron leakage or ferrous iron spillage for an extended period after the furnace resumes production.

[0062] 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 the different aspects of the invention as described above 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 rapidly dismantling and restoring a titanium slag electric furnace, characterized in that, include: A discharge port is set 300-800mm below the tapping spout of the electric furnace, and the molten iron in the electric furnace is discharged to the discharge port. Remove the refractory material above the iron discharge port, and retain the original refractory material below the iron discharge port; The original refractory materials were cleaned up, and the area above the iron drain opening was rebuilt with new refractory materials. Holes are dug in the slag below the electrodes, and the furnace drying material is refilled into the holes for furnace drying.

2. The method according to claim 1, characterized in that, Also includes: Replace the damaged refractory material near the iron discharge port.

3. The method according to claim 1, characterized in that, Before rebuilding with new refractory material, the method also includes: digging a trench between the furnace wall and the slag along the circumference of the furnace wall.

4. The method according to claim 3, characterized in that, The width of the trench is 30-50mm and the depth is 500-1000mm.

5. The method according to claim 1, characterized in that, When rebuilding with new refractory materials, multiple layers of refractory material are laid in a stepped manner towards the center of the electric furnace, moving from bottom to top.

6. The method according to claim 5, characterized in that, Each refractory layer extends no more than 10 mm beyond the adjacent refractory layer below.

7. The method according to claim 1, characterized in that, When rebuilding with new refractory materials, a gap should be left at the joint between the new refractory materials and the original refractory materials.

8. The method according to claim 7, characterized in that, The size of the gap is 2-3 mm.

9. The method according to claim 7, characterized in that, Also includes: A thermocouple is inserted at the junction of the new refractory material and the existing refractory material; and during the furnace drying process, the heating rate of the thermocouple is controlled to not exceed 1°C / h.

10. The method according to claim 9, characterized in that, The insertion size of the thermocouple is 1 / 3 to 1 / 4 of the thickness of the refractory material; and / or the depth of the cavity is 500-1000 mm.

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