A method for improving thermal insulation performance of refractory bricks for ladle

Abstract

A method for improving the thermal insulation performance of refractory bricks for ladles includes designing the material, component ratio, production process, and masonry construction process of the refractory bricks; zoning; masonry, numbering, and recording the material, component ratio, and production process parameters of the refractory bricks in each area; videotaping the entire ladle masonry process and recording the masonry construction process; using a thermal imaging temperature measurement system to measure the temperature of the ladle during continuous pouring, tracking the temperature distribution throughout the entire life cycle, and capturing high-temperature areas; analyzing and comparing the production parameters of refractory materials in the high-temperature area of ​​the ladle shell, and analyzing the masonry techniques in combination with the masonry video; performing physical and chemical analysis on refractory bricks at the end of their life; optimizing the refractory brick production process and masonry process; and repeating the above process. The present invention can compare and accelerate the exploration of the influence of refractory bricks of different materials, production processes, and masonry methods on the thermal insulation performance in the same environment, can grasp the changing rules of the thermal insulation performance of different refractory bricks as the service life extends, and formulate a reasonable offline replacement cycle.

Description

Technical Field

[0001] The invention belongs to the technical field of refractory materials for steelmaking, and particularly relates to a method for improving the thermal insulation performance of refractory bricks for a ladle. Background Art

[0002] The ladle, a container for holding and refining molten steel during the steelmaking process, reaches temperatures as high as 1500-1600°C. The entire steel holding period, from tapping from an electric furnace or converter to the completion of continuous pouring, is approximately two hours. The ladle shell temperature typically remains between 350-400°C, leading to energy loss through radiation. This phenomenon is widespread in domestic steel mills and has become an unavoidable issue in the iron and steel metallurgical industry as it strives to save energy and reduce consumption.

[0003] A 20-30°C temperature drop must be maintained between refining and tapping. Improving the ladle's thermal insulation can reduce the temperature drop during continuous pouring. This lowers the refining tapping temperature and reduces energy consumption. Preliminary estimates show that every 1°C reduction in the temperature drop for 100 tons of molten steel can reduce electricity consumption by 13 degrees Celsius. Experimental follow-up testing has shown that the optimized refractory bricks of the present invention can reduce the refining tapping temperature by at least 1°C, reducing costs by approximately 12 yuan per 100 tons of molten steel. A steel company with an annual output of 40 million tons can save approximately 5 million yuan in electricity annually. Furthermore, long-term high-temperature conditions cause creep deformation in the cladding shell, shortening its service life due to deformation. Cooling the cladding shell extends its service life, also offering significant economic benefits. Furthermore, in the later stages of its use, the cladding shell temperature can reach even higher, sometimes reaching 500°C. This creates the risk of the cladding becoming red or even piercing, posing a safety hazard. Therefore, reducing the cladding shell temperature is imperative.

[0004] The ladle consists of an outer shell welded from heat-resistant steel plates, and the inner lining from the inside to the outside is an insulation layer of about 12 mm, a permanent layer, an insulation layer, and a working layer. The working layer is used to directly contact the molten steel and slag during ladle smelting, and is eroded by the molten steel and slag, and is easily affected by large temperature differences. Therefore, the refractory materials used in the working layer are often severely damaged and need to be inspected and replaced regularly; the permanent layer is on the inside of the working layer. The permanent layer plays the role of the main skeleton of the ladle and plays a vital role in preventing molten steel leakage and maintaining the safe operation of the ladle. Therefore, the safety of the ladle is related to the quality of this layer. This layer is generally built with clay and high-alumina bricks, usually in a comprehensive masonry method; the insulation layer is an insulation brick made of some lightweight, low thermal conductivity refractory materials; the insulation layer is the outermost layer of the lining, close to the ladle shell. The main function of the insulation layer is to insulate the molten steel, reduce the heat loss of the molten steel, and reduce the energy consumption of steelmaking. The process from the working layer being put into use to its damage is generally about one month, which is called one package. The working layer is replaced after each package. The process from the permanent layer being put into use to its damage is generally 8 packages. The permanent layer is rebuilt after every 8 packages.

[0005] Lowering the ladle shell temperature primarily involves improving the thermal insulation performance of the refractory materials used in the ladle's insulation layer and permanent masonry. Different materials, different component ratios, and different production methods significantly impact the thermal insulation performance of refractory bricks, as does the masonry construction method during construction. Refractory brick R&D companies often conduct very short experiments on the thermal insulation performance of different refractory bricks, failing to measure changes in thermal insulation performance over the entire process and over a long period of time. Furthermore, laboratory experimental environments are unable to simulate the actual operating conditions of refractory bricks in the ladle, resulting in a high degree of theoretical focus and poor practical application. This results in a long development cycle for new insulating refractory bricks and suboptimal thermal insulation results. Summary of the Invention

[0006] Technical problem to be solved: In view of the problems in the above-mentioned prior art that refractory bricks for ladles cannot be tested under actual usage conditions, the differences in thermal insulation performance of different refractory bricks under the same working conditions cannot be compared, and the changes in thermal insulation performance of refractory bricks of different materials throughout their life cycle, the present invention provides a method for improving the thermal insulation performance of refractory bricks for ladles, which has the advantages of comparing the thermal insulation performance of refractory bricks of different materials, different production processes, and different masonry methods in the same environment, accelerating the exploration of the effects of different materials, different production processes, and different masonry methods on the thermal insulation performance of refractory bricks, accelerating the screening and development of thermal insulation bricks with the best thermal insulation performance, and mastering the changing rules of the thermal insulation performance of different refractory bricks with the extension of usage time, formulating a reasonable offline replacement cycle, etc.

[0007] Technical solution: A method for improving the thermal insulation performance of refractory bricks for a ladle. The ladle is placed on the upper surface of a continuous casting platform. The ladle comprises, from the outside to the inside, a ladle shell, an insulation layer, a permanent layer, an insulation layer, and a working layer. The ladle lining is divided from top to bottom into a slag line area, a molten pool area, and a ladle bottom area. The method for improving the thermal insulation performance of refractory bricks for a ladle comprises the following steps:

[0008] Step 1. Design the material, composition ratio and production process of refractory bricks for ladle lining, as well as the masonry construction process;

[0009] Step 2. Partitioning: Divide the slag line area into 8 equal areas, namely slag line areas 1 to 8, the molten pool area into 8 equal areas, namely molten pool areas 1 to 8, and the bottom area into 4 equal areas, namely bottom area 1 to 4, for a total of 20 areas;

[0010] Step 3. Lay bricks, number and spray the refractory insulation bricks in each area, record the material, composition ratio and production process of the refractory bricks in each area, so that the composition ratio and production process parameters of each numbered refractory brick can be traced;

[0011] Step 4. Videotape the entire ladle lining process, covering 20 areas separately, and record construction parameters, including the staggered pattern of bricks during construction, the thickness difference between the upper and lower platforms in the slag line area, and the thickness difference at the junction of the slag line area and the molten pool area. Analyze the video to determine whether the high ladle shell temperature is caused by the construction process.

[0012] Step 5. Use thermal imaging technology to track the temperature of each partition of the ladle throughout the entire process and life cycle, and analyze the changes in the thermal insulation performance of refractory bricks of various compositions and production processes with working conditions and length of use: Place two thermal imaging infrared thermometers 5 meters around the ladle on the continuous casting platform, with an angle of 180° between the two thermal imaging infrared thermometers. A single thermal imaging infrared thermometer completely covers half of the ladle shell. Place a thermal imaging infrared thermometer 5 meters away from the continuous casting platform and the bottom of the ladle to completely cover the bottom of the ladle. Connect the signal output terminals of the three thermal imaging infrared thermometers to the signal input terminals of the infrared thermal imaging temperature early warning system to monitor the entire continuous casting process of the ladle online. Temperature measurement, recording the temperature of each area, using infrared thermal imaging temperature warning system to capture high-temperature areas, the high-temperature area is the temperature area above 320 ° C, combined with the composition ratio and production process parameters of the refractory bricks in each area, as well as the staggered method between bricks during masonry, remove the refractory bricks at the end of their life cycle for physical and chemical analysis, and compare them with the composition, phase, and organizational structure during masonry. Analyze the impact of high-temperature environment on the internal organization and performance of refractory bricks, analyze and compare the differences in the thermal insulation performance of refractory bricks, and analyze which refractory bricks have better thermal insulation performance with which material, composition ratio and production process. Adjust the composition and organizational structure accordingly to further improve the thermal insulation performance of refractory bricks;

[0013] Step 6. Adjust the composition ratio, material, staggered method between bricks during laying, thickness difference between upper and lower platforms in the slag line area, and thickness difference at the junction of the slag line area and the molten pool area of ​​the refractory bricks in the temperature area above 320°C of the cladding shell. Conduct the experiment from step 1 again, compare the cladding shell temperature in the same area before and after improvement, judge the improvement effect, and thus determine the optimal composition ratio of refractory bricks, laying process, staggered method between bricks during laying, thickness difference between upper and lower platforms in the slag line area, and thickness difference at the junction of the slag line area and the molten pool area.

[0014] Preferably, the inner lining is a permanent layer, a thermal insulation layer and a working layer.

[0015] Preferably, in the step three, the specific numbering is as follows: the insulation bricks laid in the slag line area 1~8, the molten pool area 1~8 and the bottom area 1~4 are numbered Z-1-1 to Z-1-110, Z-2-1 to Z-2-110, Z-3-1 to Z-3-110, Z-4-1 to Z-4-110, Z-5-1 to Z-5-110, Z-6-1 to Z-6-110, Z-7-1 to Z-7-110, Z-8-1 to Z-8-11 0, R-1-1 to R-1-100, R-2-1 to R-2-100, R-3-1 to R-3-100, R-4-1 to R-4-100; R-5-1 to R-5-100, R-6-1 to R-6-100, R-7-1 to R-7-100, R-8-1 to R-48-100; D-1-1 to D-1-30, D-2-1 to D-2-30, D-3-1 to D-3--30, D-4-1 to D-4-30.

[0016] Preferably, in step five, the temperature of the entire ladle continuous casting process is measured online, and the temperature of each area is recorded, including long-term temperature measurement of the same area, tracking one ladle service, and comparing the changes in the thermal insulation performance of the refractory bricks in the working layer with different ladle ages; tracking 8 ladle services in the entire process and comparing the changes in the thermal insulation performance of the refractory bricks in the permanent layer.

[0017] Preferably, when analyzing and comparing the thermal insulation performance of refractory bricks in step 5, the temperatures of the ladle zones in the same slag line area, molten pool area or ladle bottom area are compared, and the thermal insulation performance of refractory bricks in the same working conditions is compared. The system automatically records the temperature of each ladle age within the ladle to calculate the average temperature of the ladle, and compares the thermal insulation effects of different refractory bricks.

[0018] Preferably, the items of physical and chemical analysis in step five include thermal conductivity, apparent porosity, bulk density, room temperature compressive strength, high temperature flexural strength, MgO content and Al2O3 content.

[0019] Preferably, the refractory bricks in step 3 may be lightweight mullite-corundum refractory bricks, lightweight insulation bricks, calcium hexaaluminate refractory bricks or pyrophyllite bricks.

[0020] Furthermore, the composition ratio and production process parameters of the lightweight mullite-corundum refractory bricks, lightweight thermal insulation bricks, calcium hexaaluminate refractory bricks or pyrophyllite bricks are specifically as follows:

[0021] Lightweight mullite-corundum refractory bricks (low thermal conductivity bricks): High-alumina bauxite (Al2O3 94.55%, D50 = 44um) and metallurgical wollastonite (SiO2 92.32%) are used as raw materials, polystyrene balls (<3mm) are used as pore-forming agents, and the slurry pH is adjusted with hydrochloric acid and ammonia. High-strength lightweight mullite-corundum products are prepared using a gel casting process. Firing at 1550°C results in a porosity of 87.37%, a strength of 2.17 MPa, and a thermal conductivity of 0.22 W / (mK).

[0022] Lightweight insulation brick: Ingredient ratio (mass fraction): Alumina clinker 1: Al2O3>85%, Fe2O3≤2.5%, RO≤0.7%; Alumina clinker 2: 55%-75%, Fe2O3≤2.5%, RO≤0.8%; Porous clay clinker: 40%-45%, SiO2: 50-52%, Fe2O3: 2.1-2.7%, RO: ≤0.17%, R2O≤0.5-1.2%. Bound clay: Al2O3≥33%, Fe2O3≤1.5%, Floating beads: Al2O3: 35%-43%, SiO2: 50-61%, Fe2O3=1.1%-3.3%, RO: 0.7-2.2%, R2O: 0.4%-1.6%;

[0023] Calcium hexaaluminate refractory brick (Reikege brick): Calcium hexaaluminate composition (wt%): Al2O3: 87%, CaO: 6.75%, binder: 6.8%, ball milling for 3h, forming, long-term heating and drying, high temperature synthesis;

[0024] Pyrophyllite brick: Composition (wt%): Kaolin: 37%, Aluminum oxide powder: 25%, Pyrophyllite 20%, Quartz sand: 8%, Silicon carbide: 7%, Expanding agent: 2%, Other 1%. Firing temperature: 1350℃;

[0025] The above improvements to the composition and production process are based on the temperature measurement results.

[0026] Beneficial effects:

[0027] (1) The present invention lays different refractory insulation bricks in different partitions of the ladle, and can compare the insulation performance of different insulation bricks under the same working conditions, and can trace the influence of different compositions and different production processes on the insulation performance of insulation bricks.

[0028] (2) The present invention records the construction process of the masonry by video, and can detect the changes in the thermal insulation performance of different thermal insulation bricks throughout the entire life cycle, and find the law of changes in the thermal insulation performance of thermal insulation bricks as the service life is extended.

[0029] (3) The present invention detects the temperature of the steel cladding on the continuous casting platform throughout the entire process, monitors the temperature of the steel cladding, and issues an early warning when the temperature is too high, thereby preventing safety accidents such as the cladding turning red or puncturing the cladding.

[0030] By using the method of the present invention, the thermal insulation performance of refractory bricks made of different materials, produced using different processes and laid using different methods can be compared in the same environment, thereby accelerating the exploration of the effects of different materials, produced using different processes and laid using different methods on the thermal insulation performance of refractory bricks, accelerating the screening and development of thermal insulation bricks with the best thermal insulation performance, and understanding the changing patterns of the thermal insulation performance of different refractory bricks as their use time increases, thereby formulating a reasonable offline replacement cycle. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is the main view of the ladle partition structure (only half of the partition is shown in the figure, and the other half is on the back);

[0032] Figure 2 Screenshots of the ladle thermal imaging system and the real-time video of the ladle. (a) is the thermal imaging image; (b) is the real-time video screenshot.

[0033] Figure 3 This is a comparison chart of the thermal insulation performance of low thermal conductivity ladle bricks and ordinary high alumina bricks;

[0034] Figure 4 This is a comparison chart of the thermal insulation performance of lightweight thermal insulation bricks and ordinary high-alumina bricks;

[0035] Figure 5 This is a comparison chart of the thermal insulation performance of pyrophyllite bricks and ordinary high-alumina bricks;

[0036] Figure 6 This is a comparison chart of the thermal insulation performance of calcium hexaaluminate bricks and ordinary high alumina bricks;

[0037] Figure 7 This is a process flow chart of the method for improving the thermal insulation performance of refractory bricks for ladle according to the present invention. DETAILED DESCRIPTION

[0038] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0039] The present invention provides a method for improving the thermal insulation performance of refractory bricks for a ladle. The ladle is placed on the upper surface of a continuous casting platform. The ladle comprises a ladle shell, a thermal insulation layer, a permanent layer, a thermal insulation layer and a working layer from the outside to the inside. The ladle lining (permanent layer, thermal insulation layer and working layer) is divided from top to bottom into a slag line area, a molten pool area and a ladle bottom area. Figure 7 The method for improving the thermal insulation performance of refractory bricks for ladle comprises the following steps:

[0040] Step 1. Design the material, composition ratio and production process of refractory bricks for ladle lining, as well as the masonry construction process;

[0041] Step 2. Partitioning: Divide the slag line area into 8 equal areas, namely slag line areas 1 to 8, the molten pool area into 8 equal areas, namely molten pool areas 1 to 8, and the bottom area into 4 equal areas, namely bottom area 1 to 4, for a total of 20 areas;

[0042] Step 3. Lay and number the refractory insulation bricks in each area and spray them, record the material, composition ratio and production process parameters of the refractory bricks in each area, so that the composition ratio and production process parameters of each numbered refractory brick can be traced;

[0043] Step 4. Videotape the entire ladle lining process, recording each of the 20 areas. Note the staggered pattern of bricks during construction, the thickness difference between the upper and lower platforms in the slag line area, and the thickness difference at the junction of the slag line area and the molten pool area. Analyze the video footage to determine if the high ladle shell temperature is caused by the construction process.

[0044] Step 5. Use thermal imaging technology to track the temperature of each partition of the ladle throughout the entire process and life cycle, and analyze the changes in the thermal insulation performance of refractory bricks of various compositions and production processes with working conditions and length of use: Place two thermal imaging infrared thermometers 5 meters around the ladle on the continuous casting platform, with an angle of 180° between the two thermal imaging infrared thermometers. A single thermal imaging infrared thermometer completely covers half of the ladle shell. Place a thermal imaging infrared thermometer 5 meters away from the continuous casting platform and the bottom of the ladle to completely cover the bottom of the ladle. Connect the signal output terminals of the three thermal imaging infrared thermometers to the signal input terminals of the infrared thermal imaging temperature early warning system to monitor the entire continuous casting process of the ladle online. Temperature measurement, recording the temperature of each area, using infrared thermal imaging temperature warning system to capture high-temperature areas, the high-temperature area is the temperature area above 320 ° C, combined with the composition ratio and production process parameters of the refractory bricks in each area, as well as the staggered method between bricks during masonry, remove the refractory bricks at the end of their life cycle for physical and chemical analysis, and compare them with the composition, phase, and organizational structure during masonry. Analyze the impact of high-temperature environment on the internal organization and performance of refractory bricks, analyze and compare the differences in the thermal insulation performance of refractory bricks, and analyze which refractory bricks have better thermal insulation performance with which material, composition ratio and production process. Adjust the composition and organizational structure accordingly to further improve the thermal insulation performance of refractory bricks;

[0045] Step 6. Adjust the composition ratio of refractory bricks in the temperature area above 320℃, masonry process, staggered method between bricks during masonry, thickness difference between upper and lower platforms in the slag line area, and thickness difference at the junction of the slag line area and the molten pool area. Conduct the experiment from step 1 again, compare the cladding temperature in the same area before and after improvement, judge the improvement effect, and thus determine the optimal composition ratio of refractory bricks, masonry process, staggered method between bricks during masonry, thickness difference between upper and lower platforms in the slag line area, and thickness difference at the junction of the slag line area and the molten pool area.

[0046] In one of the schemes, in the step 3, the specific numbering is as follows: the insulation bricks laid in the slag line area 1~8, the molten pool area 1~8 and the bottom area 1~4 are numbered Z-1-1 to Z-1-110, Z-2-1 to Z-2-110, Z-3-1 to Z-3-110, Z-4-1 to Z-4-110, Z-5-1 to Z-5-110, Z-6-1 to Z-6-110, Z-7-1 to Z-7-110, Z-8-1 to Z-8-1 10, R-1-1 to R-1-100, R-2-1 to R-2-100, R-3-1 to R-3-100, R-4-1 to R-4-100; R-5-1 to R-5-100, R-6-1 to R-6-100, R-7-1 to R-7-100, R-8-1 to R-48-100; D-1-1 to D-1-30, D-2-1 to D-2-30, D-3-1 to D-3--30, D-4-1 to D-4-30.

[0047] In one of the solutions, in step five, the temperature of the entire ladle continuous casting process is measured online, and the temperature of each area is recorded, including long-term temperature measurement of the same area, tracking one ladle service, and comparing the changes in the thermal insulation performance of refractory bricks in the working layer with different ladle ages; tracking 8 ladle services in the entire process and comparing the changes in the thermal insulation performance of refractory bricks in the permanent layer.

[0048] In one of the solutions, when analyzing and comparing the thermal insulation performance of refractory bricks in step five, the temperatures of the ladle zones in the same slag line area, molten pool area, or ladle bottom area are compared, and the thermal insulation performance of refractory bricks under the same working conditions is compared. The system automatically records the temperature of each ladle age within the ladle to calculate the average temperature of the ladle, and compares the thermal insulation effects of different refractory bricks.

[0049] In one of the solutions, the items of physical and chemical analysis in step five include thermal conductivity, apparent porosity, bulk density, room temperature compressive strength, high temperature flexural strength, MgO content, and Al2O3 content.

[0050] In the embodiments of this specification:

[0051] 45mm ordinary high alumina bricks, 65mm ordinary high alumina bricks, 115mm ordinary high alumina bricks, 1#70mm ordinary high alumina bricks, 2#70mm ordinary high alumina bricks, 1#90mm ordinary high alumina bricks, and 2#90mm ordinary high alumina bricks were purchased from Shanghai Lier Refractory Materials Co., Ltd.

[0052] The 50mm low thermal conductivity bricks were purchased from Dashiqiao Huailin Refractory Materials Co., Ltd.

[0053] 25mm lightweight insulation bricks were purchased from Shanghai Lier Refractory Materials Co., Ltd.

[0054] 1#60mm magnesia-alumina spinel carbon brick and 2#60mm magnesia-alumina spinel carbon brick were purchased from Jiangsu Sujia Group New Materials Co., Ltd.

[0055] The 30 mm pyrophyllite insulation bricks were purchased from Jiangsu Sujia Group New Materials Co., Ltd.

[0056] The 200 mm magnesia carbon bricks were purchased from Zhejiang Fuziling Special Refractory Co., Ltd.

[0057] Example 1

[0058] The ladle is divided into 20 zones, including the slag line, the molten pool, and the bottom of the ladle. Different insulation bricks are laid in adjacent zones. The material, composition ratio, production process, and laying construction process of the refractory bricks used in the ladle lining are designed to obtain the refractory brick laying diagram.

[0059] (1) If Figure 1 According to the refractory brick masonry diagram, the outer surface of the steel ladle shell is divided into the slag line area, the molten pool area, and the ladle bottom area. At the same level of the ladle, the slag line area is evenly divided into 8 areas, namely slag line areas 1 to 8, the molten pool area is evenly divided into 8 areas, namely molten pool areas 1 to 8, and the ladle bottom area is evenly divided into 4 areas, namely ladle bottom areas 1 to 4, separated by lines.

[0060] (2) The refractory insulation bricks in each area are numbered and sprayed according to the above numbering. The material, composition ratio and production process parameters of the refractory bricks in each area are recorded so that the composition ratio and production process parameters of each numbered refractory brick can be traced. The insulation layer is uniformly paved with nano-insulation materials from the same manufacturer. When the nano-insulation materials are laid, the joints are tight and the gap is controlled to be less than 2mm. The permanent layer is paved with refractory bricks of the same composition and production process in the same area of ​​the slag line area and the molten pool area. The insulation layer is made of insulation bricks. The 8 zones of the slag line area are paved with insulation bricks of different compositions and production processes, and the 8 zones of the molten pool area are paved with insulation bricks of different compositions and production processes. The working layer is paved with magnesia carbon bricks of the same composition and production process, whether in the slag line area or the molten pool area. The types of insulation bricks include pyrophyllite insulation bricks (such as melt pool area 1, melt pool area 2, slag line area 1, slag line area 2), lightweight insulation bricks (such as melt pool area 3, melt pool area 4, slag line area 3, slag line area 4), Ruike bricks (such as melt pool area 5, melt pool area 6, slag line area 5, slag line area 6), and low thermal conductivity bricks (such as melt pool area 7, melt pool area 8, slag line area 7, slag line area 8).

[0061] (4) The same type of insulation bricks in the same ladle partition are numbered starting from 1, and each number corresponds to the brick production process record parameter. The specific numbering is as follows: the slag line area is divided into 8 areas, the molten pool area is divided into 8 areas, and the ladle bottom area is divided into 4 areas. The insulation bricks laid in the slag line area, the molten pool area and the ladle bottom area are numbered in sequence according to the area: Z-1-1 to Z-1-110, Z-2-1 to Z-2-110, Z-3-1 to Z-3-110, Z-4-1 to Z-4-110, Z-5-1 to Z-5-110, Z-6-1 to Z-6-110, Z-7-1 to Z-7-110, Z-8-1 to Z-8-110 Z-8-110, R-1-1 to R-1-100, R-2-1 to R-2-100, R-3-1 to R-3-100, R-4-1 to R-4-100; R-5-1 to R-5-100, R-6-1 to R-6-100, R-7-1 to R-7-100, R-8-1 to R-48-100; D-1-1 to D-1-30, D-2-1 to D-2-30, D-3-1 to D-3--30, D-4-1 to D-4-30.

[0062] (5) The entire process of laying the permanent layer is recorded, mainly recording the joint spacing between each brick, the step height of the dividing line between slag line bricks and melt pool bricks, and the types of refractory clay used for different slag line bricks and melt pool bricks.

[0063] Example 2

[0064] Install an online temperature measurement system on the continuous casting platform, such as Figure 2 .

[0065] (1) Two thermal imaging cameras were placed on both sides of the continuous casting ladle within 5 meters of the continuous casting platform. The two cameras were 180 degrees apart, and each camera covered half of the side of the ladle. A thermal imaging temperature measurement camera was placed under the continuous casting ladle to cover the entire bottom of the ladle. The thermal imaging camera model is: DS-2TD6236T-50H2L.

[0066] (2) When continuous casting begins, three thermal imaging temperature measurement cameras are turned on at the same time. The main control platform will display the thermal imaging image of the entire ladle and the actual monitoring image of the ladle (see Figure 2 ).

[0067] (3) The thermal imaging screen will display different colors at different temperatures. The high temperature area is brighter. Different colors correspond to different temperature ranges. The main control system will capture the high temperature point. The high temperature area is ≥320℃. The temperature distribution of different partitions of the ladle can be judged based on the different colors.

[0068] (4) Compare the temperature distribution of different ladle zones at the same level of the slag line, molten pool, and ladle bottom, so as to determine the insulation performance of the insulation bricks built in different ladle zones. The greater the temperature difference, the greater the difference in insulation performance between two insulation bricks with different chemical compositions and different production processes. Monitor the average temperature of the ladle shell for 1-4 ladle cycles, the average temperature for 5-8 ladle cycles, and the temperature of the same ladle cycle at different ladle ages.

[0069] Example 3

[0070] The thermal insulation performance of the insulation bricks laid in different partitions of the ladle is tested throughout the entire process and compared.

[0071] (1) The refractory lining of a ladle is composed of a working layer, a permanent layer, and an insulation layer from the inside out. The permanent layer and the insulation layer are made up of 8 packages. From the completion of the refractory lining to the end of its service life, all the refractory linings in the ladle are removed and taken off the line for a total of 8 packages. After each package is completed, only the working layer is removed and a new layer of refractory bricks is laid. The service life of each new layer of refractory bricks is 70 to 85 times, that is, 70 to 85 ladle years. The insulation bricks in this follow-up test are laid in the permanent layer. Starting from the completion of the working layer, the infrared thermal imaging system placed on the continuous casting platform tests the surface temperature of the entire ladle shell for each ladle year. The average temperature of a package test is taken as the average value of the package from the time of laying to the end of the line. However, after each working layer is replaced with a new working layer of refractory bricks, the insulation performance of the ladle will be better than the ladle that was taken off the line in the previous package.

[0072] (2) By monitoring the process of a ladle from the beginning of the ladle life to the end of the ladle life, we can know the ladle shell temperature of different ladle zones in 85 ladle ages, and thus know the insulation performance of different insulation bricks. The average temperature of each ladle is taken as the temperature of the ladle. At the same time, the average temperature of the slag line area of ​​each ladle is recorded as the slag line average temperature, and the average temperature of the molten pool area is recorded as the molten pool average temperature.

[0073] The average temperature of each ladle service is taken throughout the entire ladle's service life, for a total of eight or more ladle services. During ladle construction, a portion of the ladle is partitioned with experimental refractory insulation bricks, and different areas are built with insulation bricks of different materials. In this embodiment, odd-numbered areas are standard ladle services (slag line areas 1, 3, 5, and 7; molten pool areas 1, 3, 5, and 7; and ladle bottom areas 1 and 3 are built with 115mm standard high-alumina bricks), while even-numbered areas are experimental ladle services (slag line areas 2, 4, 6, and 8; molten pool areas 2, 4, 6, and 8; and ladle bottom areas 2 and 4 are built with 50mm low-thermal-conductivity bricks and 65mm standard high-alumina bricks).

[0074] (3) List the average slag line temperature and the average molten pool temperature of each package in the same figure, such as Figure 3It can be clearly seen that for the same type of refractory insulation brick, the outer steel shell temperature increases with the increase of cladding time, indicating that the insulation performance of the insulation brick gradually deteriorates with the extension of service time. This pattern is observed for refractory bricks of various materials.

[0075] (4) From the perspective of the entire life cycle, the thermal insulation performance of the experimental ladle is better than that of the ordinary ladle. Whether from small ladle service or large ladle service, the thermal insulation performance of 1-3 ladle service has more obvious advantages. Figure 3 The shell temperature of the first three ladle samples in the experimental package was only below 280℃, while that of the ordinary package was above 310℃, whether it was the slag line temperature or the molten pool temperature.

[0076] (5) After testing the entire service life of the insulation bricks, it was found that the insulation performance of the experimental package was significantly better than that of the ordinary package.

[0077] Example 4

[0078] The same as Example 3, except that, in this embodiment, slag line areas 1 and 3; molten pool areas 1 and 3; and bottom area 1 of the package are built with 1#70mm ordinary high-alumina bricks; slag line areas 5 and 7; molten pool areas 5 and 7; and bottom area 3 of the package are built with 2#70mm ordinary high-alumina bricks. Even-numbered areas are experimental packages (slag line areas 2, 4, 6, and 8; molten pool areas 2, 4, 6, and 8; and bottom areas 2 and 4 are built with 45mm ordinary high-alumina bricks + 25mm lightweight insulation bricks). The average slag line temperature and the average molten pool temperature of each package are listed in the same figure, as shown in FIG. Figure 4 It can be seen that the thermal insulation performance of the experimental insulation bricks is significantly better than that of ordinary experimental ladle. In particular, the thermal insulation performance of the lightweight insulation bricks is 50-60℃ lower than that of ordinary ladle bricks.

[0079] Example 5

[0080] Same as Example 3, except that, in this embodiment, slag line areas 1 and 3; molten pool areas 1 and 3; bottom area 1 are built with 1#90mm ordinary high-alumina bricks; slag line areas 5 and 7; molten pool areas 5 and 7; bottom area 3 are built with 2#90mm ordinary high-alumina bricks; slag line areas 2 and 4; molten pool areas 2 and 4; bottom area 2 are built with 1#60mm aluminum-magnesium spinel carbon bricks + 30mm pyrophyllite insulation bricks; slag line areas 6 and 8; molten pool areas 6 and 8; bottom area 4 are built with 2#60mm aluminum-magnesium spinel carbon bricks + 30mm pyrophyllite insulation bricks. The average slag line temperature and the average molten pool temperature of each package are listed in the same figure, as shown in the figure below. Figure 5 It can be seen that the thermal insulation performance of the experimental insulation bricks is significantly better than that of the ordinary experimental ladle. In particular, the thermal insulation performance of the pyrophyllite insulation bricks is much lower than that of the ordinary ladle bricks.

[0081] Example 6

[0082] The same as Example 3, except that in this embodiment, the odd-numbered areas are ordinary balers (slag line areas 1, 3, 5, 7; molten pool areas 1, 3, 5, 7; baler bottom areas 1 and 3 are built with 200mm magnesia carbon bricks + 65mm ordinary high-alumina bricks), and the even-numbered areas are experimental balers (slag line areas 2, 4, 6, 8; molten pool areas 2, 4, 6, 8; baler bottom areas 2 and 4 are built with Reikege insulation bricks, i.e., 200mm magnesia carbon bricks + 65mm calcium hexaaluminate bricks). The average slag line temperature and the average molten pool temperature of each baler are listed in the same figure, as shown in the figure below. Figure 6 , it can be seen that Figure 6 There is no significant difference in thermal insulation performance between Ruikege insulation bricks and ordinary ladle bricks.

[0083] In summary, from the comparison results of Examples 3 to 6, it can be seen that the steel cladding temperature measurement and insulation brick performance improvement and enhancement system can detect the surface temperature of the steel cladding and compare the insulation performance of different insulation bricks.

[0084] The proportions and process references of the above-mentioned refractory bricks are as follows:

[0085] Lightweight mullite-corundum refractory bricks (low thermal conductivity bricks): High-alumina bauxite (Al2O394.55%, D50=44um) and metallurgical wollastonite (SiO292.32%) are used as raw materials, polystyrene balls (<3mm) are used as pore-forming agents, and hydrochloric acid and ammonia water are used to adjust the pH value of the slurry. High-strength lightweight mullite-corundum products are prepared using the gel casting process. They are fired at 1550℃, with a porosity of 87.37%. The strength of the finished bricks is 2.17Mpa and the thermal conductivity is 0.22W / (mK).

[0086] Lightweight Insulating Brick: Composition (by mass): 1% alumina clinker; Al2O3 > 85%, Fe2O3 ≤ 2.5%, RO ≤ 0.7%; 2% alumina clinker: 55%-75%, Fe2O3 ≤ 2.5%, RO ≤ 0.8%; Porous Clay Clinker: 40%-45%, SiO2: 50-52%, Fe2O3: 2.1-2.7%, RO: ≤ 0.17%, R2O ≤ 0.5-1.2%. Bound Clay: Al2O3 ≥ 33%, Fe2O3 ≤ 1.5%. Floating Beads: Al2O3: 35%-43%, SiO2: 50-61%, Fe2O3 = 1.1%-3.3%, RO: 0.7-2.2%, R2O: 0.4%-1.6%.

[0087] Calcium hexaaluminate refractory brick (Reikege brick): Calcium hexaaluminate composition (wt%): Al2O3: 87%, CaO: 6.75%, binder; 6.8%, ball milling for 3h, molding, long-term heating and drying, high temperature synthesis.

[0088] Pyrophyllite brick: Composition (wt%): Kaolin: 37%, Alumina powder: 25%, Pyrophyllite 20%, Quartz sand: 8%, Silicon carbide: 7%, Expanding agent: 2%, Other 1%. Firing temperature: 1350℃.

Claims

1. A method for improving the thermal insulation performance of refractory bricks for a ladle, wherein the ladle is placed on the upper surface of a continuous casting platform, and the ladle comprises, from the outside to the inside, a ladle shell, a thermal insulation layer, a permanent layer, a thermal insulation layer, and a working layer. The ladle lining is divided from top to bottom into a slag line area, a molten pool area, and a ladle bottom area, characterized in that: The method for improving the thermal insulation performance of refractory bricks for ladle comprises the following steps: Step 1. Design the material, composition ratio and production process of refractory bricks for ladle lining, as well as the masonry construction process; Step 2. Partitioning: Divide the slag line area into 8 equal areas, namely slag line areas 1 to 8, the molten pool area into 8 equal areas, namely molten pool areas 1 to 8, and the bottom area into 4 equal areas, namely bottom area 1 to 4, for a total of 20 areas; Step 3. Lay and number the refractory insulation bricks in each area and spray them, and record the material, composition ratio and production process of the refractory bricks in each area; Step 4. Video the entire ladle lining process, recording each of the 20 areas and recording the construction parameters, including the staggered pattern of bricks during construction, the thickness difference between the upper and lower platforms in the slag line area, and the thickness difference at the junction of the slag line area and the molten pool area; Step 5. Use thermal imaging technology to track the temperature of each partition of the ladle throughout the entire process and life cycle, and analyze the changes in the thermal insulation performance of refractory bricks of various compositions and production processes with working conditions and length of use. The details are as follows: Place two thermal imaging infrared thermometers 5 meters around the ladle on the continuous casting platform. The angle between the two thermal imaging infrared thermometers is 180 degrees. A single thermal imaging infrared thermometer completely covers half of the ladle shell. Place a thermal imaging infrared thermometer 5 meters away from the continuous casting platform and the bottom of the ladle to completely cover the bottom of the ladle. Connect the signal output ends of the three thermal imaging infrared thermometers to the signal of the infrared thermal imaging temperature early warning system. The input end is connected to measure the temperature online during the entire ladle pouring process, record the temperature of each area, and use the infrared thermal imaging temperature warning system to capture the high-temperature area, which is the temperature area above 320°C. Combined with the composition ratio and production process parameters of the refractory bricks in each area, as well as the staggered method between bricks during masonry, the refractory bricks at the end of their life cycle are removed for physical and chemical analysis, and compared with the composition, phase, and organizational structure during masonry. The impact of the high temperature environment on the internal organization and performance of the refractory bricks is analyzed, and the differences in the thermal insulation performance of the refractory bricks are analyzed and compared. The composition and organizational structure are adjusted accordingly to further improve the thermal insulation performance of the refractory bricks. Step 6. Adjust the composition ratio, material, staggered method between bricks during laying, thickness difference between upper and lower platforms in the slag line area, and thickness difference at the junction of the slag line area and the molten pool area of ​​the refractory bricks in the temperature area above 320°C of the cladding shell. Conduct the experiment from step 1 again, compare the cladding shell temperature in the same area before and after improvement, judge the improvement effect, and thus determine the optimal composition ratio of refractory bricks, laying process, staggered method between bricks during laying, thickness difference between upper and lower platforms in the slag line area, and thickness difference at the junction of the slag line area and the molten pool area.

2. The method for improving the thermal insulation performance of refractory bricks for ladle according to claim 1, characterized in that: The inner lining comprises a permanent layer, a thermal insulation layer and a working layer.

3. The method for improving the thermal insulation performance of refractory bricks for ladle according to claim 1, characterized in that: In step 5, the temperature of the entire ladle continuous casting process is measured online, and the temperature of each area is recorded, including long-term temperature measurement of the same area, tracking one ladle service, and comparing the changes in the thermal insulation performance of the refractory bricks in the working layer with different ladle ages; tracking 8 ladle services in the entire process and comparing the changes in the thermal insulation performance of the refractory bricks in the permanent layer.

4. The method for improving the thermal insulation performance of refractory bricks for ladle according to claim 1, characterized in that: When analyzing and comparing the thermal insulation performance of refractory bricks in step 5, the temperatures of the ladle zones in the same slag line area, molten pool area, or ladle bottom area are compared, and the thermal insulation performance of refractory bricks under the same working conditions is compared. The system automatically records the average temperature of each ladle age within the ladle to calculate the average temperature of the ladle, and compares the thermal insulation effects of different refractory bricks.

5. The method for improving the thermal insulation performance of refractory bricks for ladle according to claim 1, characterized in that: The items of physical and chemical analysis in step five include thermal conductivity, apparent porosity, bulk density, room temperature compressive strength, high temperature flexural strength, MgO content and Al2O3 content.

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