A method of iron making for prolonging the service life of a trough

Abstract

The application discloses a novel structure for prolonging service life of a blast furnace casthouse runner, and belongs to the technical field of blast furnace iron-making in the steel industry.The novel structure is characterized by a composite layered structure design of outer-layer active water cooling, middle-layer carbon brick buffering protection and inner-layer refractory material spraying, and is used for constructing an integrated casthouse runner structure which has the functions of active cooling, high-temperature corrosion resistance, thermal shock resistance and mechanical washing resistance, so that the working environment of the casthouse runner is fundamentally improved, the structural stability and durability are improved, the service life of the casthouse runner is greatly prolonged, and the production and maintenance cost is reduced.

Description

Technical Field

[0001] This invention belongs to the field of blast furnace ironmaking technology in the iron and steel industry, and particularly relates to an ironmaking method for extending the service life of iron troughs. Background Technology

[0002] Blast furnace ironmaking is a core link in the modern steel industry. The main tapping trough in front of the furnace, as a key component of the blast furnace tapping system, undertakes the functions of guiding, conveying and initially separating high-temperature molten iron and slag. Its service performance and service life directly determine the continuity of blast furnace production, operating efficiency and overall production cost. It is a key infrastructure to ensure the efficient and stable operation of the blast furnace.

[0003] Under the intensified smelting mode of large blast furnaces, the tapping trough is subjected to multiple extreme working conditions for a long time: continuous chemical erosion of high-temperature slag and iron at 1450-1550℃, severe thermal shock impact caused by tapping intervals, physical scouring and wear of high-speed flowing slag and iron, plus the influence of furnace charge dust and mechanical vibration, the lining material is prone to rapid aging and damage.

[0004] Currently, traditional tapping troughs mostly use a single refractory material structure, which has obvious technical shortcomings: First, their resistance to high-temperature erosion and thermal shock is limited. Tapping troughs in small and medium-sized blast furnaces often require local repairs every 3-7 days, and even large blast furnaces cannot meet the needs of long-term continuous production. Second, they lack layered protection and stress buffer design, so local damage can easily spread into large-area damage, making repairs difficult and causing long downtime. Third, maintenance costs are high. Frequent repairs consume a lot of refractory materials and manpower, and the tapping spout may need to be replaced, which can easily cause fluctuations in furnace conditions.

[0005] As the steel industry transforms towards large-scale, high-efficiency, and green production, the increased smelting intensity places higher demands on the performance of tapping troughs. Simply optimizing refractory material formulations cannot fundamentally solve the problem of complex damage, and the effect of extending service life is limited. Therefore, developing a new type of tapping trough with active cooling, layered protection, and resistance to erosion and scour is crucial. Overcoming technical bottlenecks from both structural design and material combination perspectives, extending service life, reducing maintenance frequency, and lowering production costs, has become a core issue urgently needing to be addressed in the furnace front process field, and has significant industry application value and promotional significance. Summary of the Invention

[0006] This invention addresses the technical shortcomings of existing blast furnace tapping troughs, such as short service life, frequent maintenance, high operating costs, and poor structural stability. It provides a novel structure to extend the service life of the blast furnace tapping trough. Through a composite layered structure design—an outer layer of active water cooling, a middle layer of carbon brick buffer protection, and an inner layer of refractory material spraying—an integrated tapping trough structure is constructed that combines active cooling, resistance to high-temperature erosion, thermal shock resistance, and mechanical erosion resistance. This fundamentally improves the working environment of the tapping trough, enhances structural stability and durability, significantly extends its service life, and reduces production and maintenance costs.

[0007] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0008] This invention discloses an ironmaking method for extending the service life of iron troughs, comprising:

[0009] (a) Installation of the outer water-cooled cooling wall

[0010] Installation is carried out strictly according to the design dimensions to ensure that the inner wall of the cooling wall forms a standard U-shaped profile with an overall depth of 2 meters. The segmented interfaces of the cooling wall are connected by flange sealing, and the docking ends are precisely aligned with the installation positions of the blast furnace taphole and the iron swing. After the cooling wall is positioned, it is fixed to ensure that the cooling wall is installed firmly without shaking or displacement.

[0011] Cooling water circulation system connection: Connect the cooling wall inlet and outlet to the external cooling water pool and circulation pump respectively through high temperature resistant pipes, install control valves, pressure gauges, flow meters and other auxiliary components, build a closed-loop cooling water circulation system, ensure that the pipes are laid smoothly and fixed firmly to avoid pipe bends and blockages, and initially complete the cooling system piping installation;

[0012] (ii) Laying of small charcoal bricks in the middle layer

[0013] Standardized small carbon bricks are laid tightly on the inner side of the cooling wall in sequence. The laying sequence is gradually advanced from the bottom of the trench to the side walls. The carbon bricks are tightly spliced ​​together with uniform gaps. The gaps are filled with high-temperature resistant castable material to ensure that there are no gaps or misalignments.

[0014] (iii) Spraying of inner refractory material

[0015] High-pressure spraying equipment sprays refractory spraying material onto the inner side of the carbon brick buffer layer, controlling the spraying thickness to be uniform and consistent. The total spraying thickness is carried out in accordance with the design standards to ensure the formation of a dense and solid refractory working layer.

[0016] (iv) Inspection of the entire iron trench

[0017] A comprehensive inspection was conducted on the joints of the three-layer structure, and gaps and loose parts were repaired to ensure that the overall structure was sealed and secure.

[0018] Furthermore, after the cooling wall is positioned, it is fixed to the support structure using pre-embedded bolts to ensure that the cooling wall is installed firmly without shaking or displacement.

[0019] Furthermore, after the carbon bricks are laid, the flatness of the inner wall is inspected, and any protrusions or misalignments are corrected to ensure that the surface of the carbon brick layer is flat, smooth, without sharp edges or depressions, thus laying the foundation for subsequent refractory material spraying.

[0020] Furthermore, after the refractory spray coating has been cured, the U-shaped iron outlet ditch is repaired as a whole, and residual debris and dust inside the ditch are cleaned.

[0021] Furthermore, the uneven areas and sharp edges of the sprayed coating are polished and repaired to ensure that the inner wall of the ditch is smooth and the flow of molten iron is unobstructed.

[0022] Furthermore, the refractory spraying process begins at the bottom of the trench and gradually sprays upwards onto both side walls.

[0023] Furthermore, this method fundamentally improves the working environment of the iron tapping trough, enhances structural stability and durability, significantly extends the service life of the iron tapping trough, and reduces production and maintenance costs.

[0024] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0025] This invention utilizes a composite layered structure design, consisting of an outer active water cooling layer, a middle carbon brick buffer protection layer, and an inner refractory material spraying layer, to construct an integrated iron tapping trough structure that combines active cooling, resistance to high-temperature erosion, thermal shock resistance, and mechanical erosion resistance. This fundamentally improves the working environment of the iron tapping trough, enhances structural stability and durability, significantly extends the service life of the iron tapping trough, and reduces production and maintenance costs. Detailed Implementation

[0026] The blast furnace tapping trough of this invention is a U-shaped ditch structure with a depth of 2 meters.

[0027] The overall structure, from the outside in, consists of a water-cooled cooling wall layer, a carbon brick buffer layer, and a refractory material spraying layer, along with a cooling water circulation system to achieve continuous and stable water cooling. The specific structural components are as follows: 1. Outer Water-Cooled Cooling Wall System: The water-cooled cooling wall is the outer protective structure of the tapping trough, made of high-strength heat-resistant cast iron or steel. It is integrally formed to fit the outline of the U-shaped trough, completely enclosing the bottom and side walls of the tapping trough to form a complete external protective shell. The interior of the cooling wall is evenly distributed with spiral or reciprocating cooling water flow channels. The inner walls of these channels are smooth and free from blockages, ensuring smooth cooling water flow. Cooling water inlets and outlets are located at both ends of the cooling wall, connecting to an external cooling water circulation pump and cooling water pool to form a closed-loop cooling water circulation system. By continuously introducing ambient temperature cooling water, it quickly absorbs and dissipates heat from inside the trough, controlling the working temperature of the tapping trough lining within a reasonable range and preventing material damage and structural deformation caused by continuous high-temperature accumulation. 2. Middle Layer Small Carbon Brick Buffer and Protective Layer: This layer of small carbon bricks is laid inside the water-cooled cooling wall, tightly adhering to the inner wall and filling the space between the cooling wall and the inner refractory spray layer, forming a uniformly thick buffer and protective structure. The carbon bricks are high-density small-block carbon bricks with excellent high-temperature resistance, slag erosion resistance, thermal conductivity, and thermal shock stability. Each carbon brick is standardized in size, facilitating installation and subsequent localized replacement and maintenance. The spaces between the carbon bricks are filled with high-temperature resistant castable, ensuring a tight, gap-free seal and overall structural integrity and stability. This carbon brick layer efficiently conducts heat from the inner layer to the outer cooling wall, enabling rapid heat dissipation; it also buffers thermal stress caused by high temperatures, preventing stress concentration that could lead to cracking of the refractory layer. 3. Inner Layer Refractory Material: This layer uses high-temperature resistant, erosion-resistant, and scour-resistant refractory spray material, uniformly sprayed onto the inner side of the carbon brick buffer layer using high-pressure spraying equipment. The spray thickness is uniform and controllable, resulting in a smooth, flat surface that forms a dense and robust U-shaped flow-guiding working surface. It possesses excellent high-temperature strength, resistance to slag and iron erosion, thermal shock resistance, and wear resistance. It can withstand the direct scouring and chemical erosion of high-temperature slag and iron for a long time without cracking, peeling, or damage. 4. The U-shaped channel has an integral structure. The tapping channel is integrally formed into a U-shape with a depth of 2 meters. The inner wall of the channel is smooth and the transition is rounded, with no dead corners or protrusions, ensuring smooth flow of molten iron and avoiding eddy currents and stagnation that would exacerbate local erosion. One end of the channel connects to the blast furnace taphole, and the other end smoothly connects to the molten iron swing nozzle, realizing the smooth flow of high-temperature molten iron from the blast furnace taphole to the swing nozzle. There is no leakage or blockage throughout the process, meeting the requirements of continuous tapping operations in the blast furnace.

[0028] This invention relates to a structure that extends the service life of the tapping trough in front of a blast furnace. The implementation process is clear and the construction technology is controllable. It can be implemented according to the following steps: construction preparation → installation of the outer water-cooled cooling wall → laying of the middle layer of small carbon bricks → spraying of the inner refractory material → U-shaped ditch repair → cooling water system commissioning → trial operation and acceptance. The specific implementation method is as follows:

[0029] (a) Installation of the outer water-cooled cooling wall

[0030] Installation strictly adheres to design dimensions, ensuring the inner wall of the cooling wall forms a standard U-shaped profile with an overall depth of 2 meters. The segmented interfaces of the cooling wall utilize flanged sealing connections, with the mating ends precisely aligned with the blast furnace taphole and the iron swing plate installation position. After the cooling wall is positioned, it is secured to the supporting structure using pre-embedded bolts, ensuring a firm installation without shaking or displacement.

[0031] Cooling water circulation system connection: Connect the cooling wall inlet and outlet to the external cooling water pool and circulation pump respectively through high-temperature resistant pipes, install auxiliary components such as control valves, pressure gauges, and flow meters, and build a closed-loop cooling water circulation system. The pipes are laid smoothly and fixed firmly to avoid pipe bends and blockages. The initial installation of the cooling system piping is completed.

[0032] (ii) Laying of small charcoal bricks in the middle layer

[0033] Standardized small carbon bricks are laid tightly on the inner side of the cooling wall in sequence, progressing from the bottom of the trench to the side walls. The carbon bricks are tightly joined with uniform gaps, which are filled with high-temperature resistant refractory material to ensure no voids or misalignments. After the carbon bricks are laid, the flatness of the inner wall is checked, and any protrusions or misalignments are corrected to ensure that the surface of the carbon brick layer is flat, smooth, and free of sharp edges or depressions, laying the foundation for subsequent refractory material spraying.

[0034] (iii) Spraying of inner refractory material

[0035] High-pressure spraying equipment applies refractory coating material to the inner side of the carbon brick buffer layer. The spraying process begins at the bottom of the trench and gradually progresses upwards to the side walls, ensuring a uniform coating thickness. The total coating thickness adheres to design standards to guarantee the formation of a dense and robust refractory working layer. After the refractory coating layer has cured, the U-shaped tapping trench is repaired, removing residual debris and dust. Uneven areas and sharp edges of the coating are ground and repaired to ensure a smooth inner wall and unobstructed flow of molten iron.

[0036] (iv) Inspection of the entire iron trench

[0037] A comprehensive inspection was conducted on the joints of the three-layer structure, and gaps and loose parts were repaired to ensure that the overall structure was sealed and secure.

[0038] The technical solution of the present invention will be described in detail below with reference to the embodiments.

[0039] Example 1

[0040] A certain 2000m 3Due to space constraints, thick refractory lining could not be used for the tapping trough of the blast furnace. Thin refractory lining troughs posed safety hazards and increased maintenance frequency. Therefore, the technology of this invention was adopted for the 2000m... 3 The renovation of the blast furnace iron trough has significantly extended its service life.

[0041] Example 2

[0042] A certain 3000m 3 Due to raw material factors, the blast furnace produced significantly higher levels of harmful elements in the molten iron compared to other companies in the industry, resulting in noticeable erosion of the iron trough and a shortened service life. This invention was subsequently applied to the 3000m... 3 The renovation of the blast furnace iron trough has significantly extended its service life.

[0043] Example 3

[0044] A certain 4000m 3 This extra-large blast furnace, with a daily capacity of nearly 9,800 tons, suffers from severe scouring and erosion of the trough by molten iron. Operators at the furnace have placed higher demands on the quality of the trough. However, there is limited room for improvement in refractory material quality alone, and this would easily increase the cost per ton of iron. Therefore, the technology of this invention was adopted for a 4,000m... 3 The blast furnace iron trough was renovated, which significantly reduced the erosion of the trough by molten iron and extended its service life.

[0045] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for extending the service life of iron troughs, characterized in that, include: (a) Installation of the outer water-cooled cooling wall Installation is carried out strictly according to the design dimensions to ensure that the inner wall of the cooling wall forms a standard U-shaped profile with an overall depth of 2 meters. The segmented interfaces of the cooling wall are connected by flange sealing, and the docking ends are precisely aligned with the installation positions of the blast furnace taphole and the iron swing. After the cooling wall is positioned, it is fixed to ensure that the cooling wall is installed firmly without shaking or displacement. Cooling water circulation system connection: Connect the cooling wall inlet and outlet to the external cooling water pool and circulation pump respectively through high temperature resistant pipes, install control valves, pressure gauges, flow meters and other auxiliary components, build a closed-loop cooling water circulation system, ensure that the pipes are laid smoothly and fixed firmly to avoid pipe bends and blockages, and initially complete the cooling system piping installation; (ii) Laying of small charcoal bricks in the middle layer Standardized small carbon bricks are laid tightly on the inner side of the cooling wall in sequence. The laying sequence is gradually advanced from the bottom of the trench to the side walls. The carbon bricks are tightly spliced ​​together with uniform gaps. The gaps are filled with high-temperature resistant castable material to ensure that there are no gaps or misalignments. (iii) Spraying of inner refractory material High-pressure spraying equipment sprays refractory spraying material onto the inner side of the carbon brick buffer layer, controlling the spraying thickness to be uniform and consistent. The total spraying thickness is carried out in accordance with the design standards to ensure the formation of a dense and solid refractory working layer. (iv) Inspection of the entire iron trench A comprehensive inspection was conducted on the joints of the three-layer structure, and gaps and loose parts were repaired to ensure that the overall structure was sealed and secure.

2. The ironmaking method for extending the service life of iron troughs according to claim 1, characterized in that, After the cooling wall is positioned, it is fixed to the support structure using pre-embedded bolts to ensure that the cooling wall is installed firmly without shaking or displacement.

3. The ironmaking method for extending the service life of iron troughs according to claim 1, characterized in that, After the charcoal bricks are laid, the flatness of the inner wall is checked, and any protrusions or misalignments are corrected to ensure that the surface of the charcoal brick layer is flat, smooth, and free of sharp edges and depressions, laying the foundation for subsequent refractory material spraying.

4. The ironmaking method for extending the service life of iron troughs according to claim 1, characterized in that, After the refractory spray coating is cured, the U-shaped iron outlet ditch is repaired and the remaining debris and dust inside the ditch are cleaned.

5. The ironmaking method for extending the service life of iron troughs according to claim 4, characterized in that, Polish and repair any uneven or sharp areas of the sprayed coating to ensure a smooth inner wall of the ditch and unobstructed flow of molten iron.

6. The ironmaking method for extending the service life of iron troughs according to claim 1, characterized in that, The refractory spraying process begins at the bottom of the trench and gradually sprays upwards onto both side walls.

7. The ironmaking method for extending the service life of iron troughs according to claim 1, characterized in that, This method fundamentally improves the working environment of the iron tapping trough, enhances structural stability and durability, significantly extends the service life of the iron tapping trough, and reduces production and maintenance costs.