An in-situ testing platform and method for hot strength of metallurgical furnace charge

Abstract

This invention discloses an in-situ testing platform and method for the hot strength of metallurgical furnace charge, belonging to the technical field of metallurgical furnace charge performance testing equipment. The testing platform includes a heating unit, a gas distribution unit, a sample placement and support unit, and a pressure bar testing unit. The heating unit includes a furnace chamber, the inner cavity of which is a vertically rotated symmetrical cavity equipped with heating components. The sample placement and support unit includes a vertically arranged connecting column, the axis of which coincides with the axis of the furnace chamber, and its top is located inside the furnace chamber, with at least two sample support seats spaced circumferentially around the axis of the furnace chamber. The bottom of the connecting column extends to the outside of the furnace chamber. A rotation unit is used to move the at least two sample support seats to the area below the pressure bar testing unit. This design can improve the consistency of the reduction degree among multiple samples, thereby effectively reducing the fluctuation range of the measured compressive strength.

Description

Technical Field

[0001] This invention relates to the field of metallurgical furnace charge performance testing equipment, and more specifically, to an in-situ testing platform and testing method for the hot strength of metallurgical furnace charges. Background Technology

[0002] As an important metallurgical furnace charge, the compressive strength of iron ore pellets is a key indicator for evaluating their metallurgical performance. For blast furnaces / vertical shaft furnaces and their charge column structures, the charge must withstand significant mechanical stress after entering the furnace. Its compressive strength under high-temperature conditions directly determines the load-bearing capacity of the charge column, airflow distribution, and reduction efficiency. If the compressive strength of the pellets is insufficient at high temperatures, they are prone to premature pulverization in the reduction zone, producing fine particles that block airflow channels, and in severe cases, even leading to operational accidents such as charge column collapse. Therefore, accurate measurement of the dynamic reduction strength of iron ore pellets is of great significance for guiding actual production.

[0003] Current research still mainly relies on conventional hot-state strength evaluation methods. Generally, after reducing the pellets at a specific temperature, the pellets are cooled and then tested for strength, or the pellets are removed at a high temperature for compressive strength determination. These methods have the following drawbacks: First, during the cooling process, the internal crystal structure of the pellets undergoes a phase transition, causing the measured compressive strength to fail to accurately reflect its mechanical properties under high-temperature reduction conditions. Second, exposing pellet samples that have not fully cooled to air will cause continuous oxidation, altering their phase composition and making it even more difficult to accurately characterize the hot-state compressive strength of the pellets during the actual reduction process.

[0004] Existing research has attempted to conduct in-situ compressive strength testing under high-temperature conditions. For example, Chinese patent application CN219455784U discloses an automatic continuous testing device for the high-temperature compressive strength of blast furnace burdens under a multi-atmosphere environment. This device includes a heating unit, a gas mixing unit, a circulating water cooling unit, a loading and pushing unit, a force application and measurement unit, an image acquisition unit, and a control unit. This device can test the high-temperature compressive strength of various furnace burdens such as pellets, coke, sinter, and lump ore, and can automatically and continuously test multiple samples within the temperature range of 900–1600°C. However, the compressive strength measured for the same group of samples in this type of testing device fluctuates significantly, and the accuracy of the data needs further improvement. Summary of the Invention

[0005] To address the insufficient accuracy of existing in-situ testing methods for the hot strength of metallurgical furnace charges, this invention provides an in-situ testing platform and method for the hot strength of metallurgical furnace charges. This approach, through optimized design of the furnace structure and the sample-laying support unit within the testing platform, effectively improves the consistency of the reconstruction of multiple samples, thereby reducing the fluctuation range of the sample's compressive strength and ultimately enhancing the accuracy of the obtained compressive strength.

[0006] To achieve the above objectives, the technical solution provided by the present invention is as follows:

[0007] The first aspect of this invention provides an in-situ testing platform for the hot strength of metallurgical furnace charge, comprising: a heating unit including a furnace chamber, the inner cavity of which is a vertically rotated symmetrical cavity and equipped with heating components; a gas distribution unit for providing the atmosphere required for the inner cavity of the furnace chamber; a pressure bar detection unit extending from top to bottom from the outside of the furnace chamber to its inner cavity, for applying pressure to the sample inside the furnace chamber and detecting the pressure; and a sample placement bearing unit including a rotating unit and a vertically arranged connecting column, the axis of the connecting column coinciding with the axis of the inner cavity of the furnace chamber, the top of the connecting column located in the inner cavity of the furnace chamber and equipped with at least two sample bearing seats, the at least two sample bearing seats being spaced apart in a circumferential direction with the axis of the inner cavity of the furnace chamber as the center, and the bottom of the connecting column extending to the outside of the furnace chamber; the rotating unit is used to drive the bottom of the connecting column to rotate along its own axis, so as to drive the at least two sample bearing seats to move to the bottom of the pressure bar detection unit.

[0008] Furthermore, the top of the sample support is provided with a sample placement groove, which is a V-shaped groove with the opening facing upward and the opening angle being 140~150°.

[0009] Furthermore, the sample support is set out from the top of the connecting column, and the side wall has a gas channel extending toward and communicating with the V-shaped groove.

[0010] Furthermore, the number of gas channels is at least two, and the at least two gas channels are distributed at intervals along the circumferential direction with the axis of the sample carrier as the center.

[0011] Furthermore, the inner sidewall of the lower part of the furnace is slidably sleeved on the outside of the connecting column, and the heating unit also includes a lifting assembly. The lifting assembly is set on the outside of the furnace and is used to drive the furnace to move vertically relative to the connecting column, so as to form a heating chamber between the connecting column and the inner cavity of the furnace.

[0012] Furthermore, the pressure bar detection unit includes a force measuring component and a force applying component. The force measuring component is located outside the furnace, and the top of the force applying component is connected to the force measuring component, while the bottom extends into the inner cavity of the furnace and is fixedly installed on the furnace wall. The force applying component includes a detachably connected pressure bar body and a pressure bar head. The pressure bar body is made of corundum material, and the pressure bar head is made of graphite material.

[0013] Furthermore, the testing platform also includes an observation unit, which includes a horizontally arranged observation channel. One end of the observation channel extends into the inner cavity of the furnace and faces the side wall of the lower part of the pressure bar testing unit, while the other end is located outside the furnace and is fixedly installed on the furnace wall for observing the sample placed in the sample carrier.

[0014] Furthermore, the heating assembly includes a thermocouple fixedly installed in the inner cavity of the furnace and at least two vertically arranged silicon molybdenum rods. The at least two silicon molybdenum rods are arranged in a circumferential array with the axis of the furnace as the center, and the temperature measuring end of the thermocouple is set close to the test sample placed in the sample carrier.

[0015] Furthermore, the gas distribution unit includes a gas distribution cabinet and multiple air supply channels extending into the furnace cavity. The gas distribution cabinet is located outside the furnace, and its outlet end is connected to multiple air supply channels. The multiple air supply channels are distributed circumferentially with the axis of the furnace cavity as the center.

[0016] The second aspect of the present invention provides a method for in-situ testing of the hot strength of metallurgical furnace charge. The testing method uses the in-situ testing platform for the hot strength of metallurgical furnace charge of any of the above claims. The method includes: placing the sample to be tested in a sample carrier, and then placing the sample carrier in the inner cavity of the furnace to form a heating cavity between the connecting column and the inner cavity of the furnace. An inert atmosphere is continuously introduced into the furnace through the gas distribution unit at a flow rate of 5L / min to 10L / min. The heating components heat the furnace cavity to the set temperature and hold it for 15 to 30 minutes. Then, a reducing atmosphere is continuously introduced into the furnace through the gas distribution unit. After the set reduction time is reached, the rotating unit drives the sample in the sample carrier to move sequentially to the bottom of the pressure bar detection unit. The pressure bar detection unit applies pressure to the sample placed in the sample carrier and crushes it, and records the force value during the crushing process.

[0017] Compared with the prior art, the technical solution provided by this invention has the following advantages: (1) This invention designs an in-situ testing platform for the hot strength of metallurgical furnace charge. Specifically, the inner cavity of the furnace is a vertically rotated symmetrical cavity; at least two sample support seats are distributed circumferentially around the axis of the inner cavity of the furnace. Through the above design, the difference in atmosphere between the regions where multiple samples are located in the furnace can be reduced, which is conducive to improving the consistency of the reduction degree of multiple samples, thereby effectively reducing the fluctuation range of the compressive strength measured by the same group of samples. At the same time, the rotating unit drives at least two sample support seats to move to the bottom of the pressure bar testing unit. Thus, it can be seen that multiple pellets can be continuously tested using this testing platform, which improves the reliability of the measured sample data and effectively ensures the experimental efficiency.

[0018] (2) The present invention further optimizes the design of the support base used for the sample. Specifically, the top of the sample support base is provided with a sample placement groove. The sample placement groove is a V-shaped groove with an upward opening and an opening angle of 140~150°. This opening angle design allows the pellet to automatically position itself in the center of the V-shaped groove by gravity after placement, and the sample can roll slightly in the V-shaped groove and automatically reset, ensuring that the contact point between the pressure rod detection unit and the pellet is consistent during each crushing test. More importantly, when plastic deformation occurs, the design of the V-shaped groove can effectively prevent the pellet from contacting the groove wall too early, ensuring the verticality of pressure transmission and the accuracy of measurement results.

[0019] (3) The present invention further optimizes the design of the support bearing seat of the sample. Specifically, the side wall of the sample bearing seat is provided with a gas channel extending toward and communicating with the V-shaped groove, which reduces the atmospheric difference between the upper and lower outer surfaces of a single sample and effectively improves the consistency of the reduction degree between the upper and lower parts of a single sample.

[0020] (4) The present invention further optimizes the design of the pressure bar detection unit. Specifically, the pressure bar body and the pressure bar head are detachably connected. The pressure bar body is made of corundum material, which can effectively ensure the overall mechanical strength of the force application component. The pressure bar head is made of graphite material, which helps to reduce the adhesion between the sample and the pressure bar head. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the composition and structure of the in-situ testing platform for the hot strength of metallurgical furnace charge according to the present invention.

[0022] Figure 2 This is a schematic diagram of the composition of the force-applying component in this invention.

[0023] Figure 3 This is a cross-sectional schematic diagram of the internal structure of the sample support in this invention.

[0024] Figure 4This is a graph showing the variation of the hot and cold strength of the pellets in the experimental group of this invention with reduction time.

[0025] Figure 5 This is a microstructure diagram of the pellets in this invention under different cooling methods and reduction times.

[0026] Figure 6 This is a graph showing the change in reduction degree as a function of reduction time for the experimental group, control group, and standard group of this invention.

[0027] Figure 7 The graph shows the variation of the thermal intensity of the experimental and control groups of this invention with reduction time.

[0028] Explanation of icon numbers: 1. Compression bar detection unit; 101. Force measuring component; 102. Force application component; 121. Compression bar indenter; 122. Compression bar body; 2. Control unit; 3. Heating unit; 301. Furnace chamber; 302. Silicon molybdenum rod; 303. Thermocouple; 304. Lifting assembly; 4. Gas distribution unit; 401. Gas distribution cabinet; 402. Air supply duct; 5. Lofting support unit; 501. Sample support seat; 511. Sample placement groove; 512. Gas channel; 502. Rotation unit; 503. Connecting column; 6. Observation unit; 601. Observation channel; 602. Observation lens; 7. Frame. Detailed Implementation

[0029] To further understand the content of this invention, a detailed description of the invention will be provided in conjunction with the accompanying drawings and embodiments.

[0030] The structures, proportions, and sizes illustrated in the accompanying drawings are merely for illustrative purposes and to aid those skilled in the art in understanding and reading the invention. They are not intended to limit the scope of the invention and therefore have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effectiveness and purpose of the invention, should still fall within the scope of the technical content disclosed herein. Furthermore, terms such as "upper," "lower," "left," "right," and "middle" used in this specification are merely for clarity and not intended to limit the scope of implementation. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention's implementation.

[0031] refer to Figure 1As shown, this embodiment provides an in-situ testing platform for the hot strength of metallurgical furnace charge. The testing platform includes a heating unit 3, a gas distribution unit 4, a sample placement and support unit 5, and a pressure bar testing unit 1. The heating unit 3 includes a furnace chamber 301 and a heating assembly. The inner cavity of the furnace chamber 301 is a vertically rotating symmetrical cavity and is equipped with the heating assembly. The gas distribution unit 4 provides the required atmosphere for the inner cavity of the furnace chamber 301. The pressure bar testing unit 1 extends from the outside of the furnace chamber 301 to its inner cavity from top to bottom, and is used to apply pressure to the sample inside the furnace chamber 301 and detect the pressure. The sample placement and support unit 5 includes a rotating single... The unit 502 and the vertically arranged connecting column 503 are arranged together. The axis of the connecting column 503 coincides with the axis of the inner cavity of the furnace 301. The top of the connecting column 503 is located in the inner cavity of the furnace 301 and is provided with at least two sample carrier seats 501. The at least two sample carrier seats 501 are distributed circumferentially around the axis of the inner cavity of the furnace 301. The bottom of the connecting column 503 extends to the outside of the furnace 301. The rotating unit 502 is used to drive the bottom of the connecting column 503 to rotate along its own axis, so as to drive the at least two sample carrier seats 501 to move to the bottom of the pressure bar detection unit 1.

[0032] It should be noted that when using a pusher-type tube furnace or a rectangular furnace chamber, dead airflow zones and temperature gradients are prone to exist within the furnace chamber. Consequently, differences in the atmosphere between the regions where multiple samples are located lead to variations in the reduction degree among the samples. In this invention, the furnace chamber 301 adopts a vertical rotationally symmetrical cavity, which helps to reduce dead airflow zones and temperature gradients. At least two sample support seats 501 are distributed circumferentially around the axis of the furnace chamber 301, which can mitigate differences in the atmosphere within the furnace chamber and reduce the differences in the atmosphere between the regions where multiple samples are located within the furnace chamber. This helps to improve the consistency of the reduction degree among multiple samples, thereby effectively reducing the fluctuation in compressive strength caused by differences in the reduction degree of the tested samples. When the sample inside the furnace 301 reaches the set reduction parameters, the rotating unit 502 drives the bottom of the connecting column 503 to rotate along its own axis, thereby moving at least two sample carriers 501 to the underside of the pressure bar detection unit 1. The pressure bar detection unit 1 applies pressure to the sample located in the sample carrier 501 and detects the pressure, thus achieving in-situ detection of the hot strength of the metallurgical furnace charge. Simultaneously, this detection platform can also continuously test multiple pellets, improving the reliability of sample data and effectively ensuring experimental efficiency.

[0033] To improve the automation level of the testing, the testing platform also includes a control unit 2. Control unit 2 is connected to the heating unit 3, the gas distribution unit 4, the sample placement bearing unit 5, and the pressure bar detection unit 1, respectively. It receives feedback information from each of these units and issues corresponding control commands to achieve automatic operation of the testing platform and automatic acquisition of testing data. The specific implementation of this part uses existing technology and will not be described in detail here.

[0034] The bottom of the rotating unit 502 is fixedly mounted on the frame 7, and the frame 7 supports the rotating unit 502 and its components.

[0035] In some specific embodiments, the number of sample support seats 501 is generally designed to be 8 to 10, which helps to improve the representativeness of the tested sample and thus improve the accuracy of the measured compressive strength.

[0036] During the in-situ hot strength test, the inventors further discovered the following problem: Since the pellet is spherical, if an annular retaining ring is only fixed to the top surface of the connecting column, and the sample is placed inside the retaining ring to prevent movement outside the ring, then the connecting column 503 provides point support for the sample. If this method is used to support the sample, it is prone to rolling or slipping under stress, resulting in pressure not being applied vertically, and consequently, missing or distorted test data.

[0037] To address the aforementioned issues, the inventors further improved the sample support method by fixing a sample support seat at the top of the connecting column 503, and providing an arc-shaped groove on the top surface of the sample support seat that adapts to the outer surface of the sample bottom. Simultaneously, the strength change curve of the pellets during the crushing process was studied. The study revealed that in the early stage of pellet reduction, brittle fracture was the primary characteristic; the pellets shattered instantaneously under pressure, and the compressive strength could be directly and accurately measured at this point. However, in the later stage of reduction, the pellets became more plastic, exhibiting primarily plastic deformation. When the sample was flattened in the arc-shaped groove, the deformed sample would contact and be compressed against the sidewall of the groove, resulting in the measured strength value not being purely the vertical compressive strength, thus introducing a deviation in the measurement result. In summary, while the arc-shaped groove solved the sample slippage problem, it still presents the technical problem of insufficient accuracy in measuring compressive strength.

[0038] To further address the aforementioned technical problem of insufficient accuracy in compressive strength, refer to Figure 3As shown, the top of the sample support 501 has a sample placement groove 511, which is a V-shaped groove with an upward opening angle of 140-150°. This opening angle design allows the pellet to automatically position itself in the center of the groove by gravity after placement, and the sample can roll slightly in the V-shaped groove and automatically reset, ensuring that the contact point between the pressure rod detection unit 1 and the pellet is consistent during each crush test. More importantly, the V-shaped groove opening design avoids premature contact between the pellet and the groove wall during plastic deformation, ensuring the verticality of pressure transmission and the accuracy of measurement results. Further preferably, the angle between the side wall of the V-shaped groove and the horizontal plane is 15° to 30°.

[0039] During the research process, the inventors also noticed that there was an uneven reduction degree between the upper and lower outer surfaces of a single sample, especially in the area below the V-groove contact line of the sample. This area formed an airflow dead zone, resulting in insufficient reduction of the pellets.

[0040] To further address the aforementioned issues, the sample support 501 protrudes from the top of the connecting column 503, and its side wall has a gas channel 512 extending towards and communicating with the V-shaped groove. By adding the gas channel 512, the atmospheric difference between the upper and lower outer surfaces of a single sample is reduced, which not only improves the consistency of the reduction degree between the upper and lower parts of a single sample, but also improves the reduction degree of the pellets.

[0041] In some embodiments, the number of gas channels 512 is at least two, and the at least two gas channels 512 are distributed circumferentially around the axis of the sample support 501. By providing multiple gas channels 512, the gas flow inside the furnace 301 can flow through the gas channels 512 to the bottom of the V-groove.

[0042] The sample placement groove 511 in the sample support 501 is designed with an opening angle of 140~150° as a V-shaped groove, and the number of gas channels 512 is set to six. This sample support 501 structure is used as the experimental group, and the degree of reduction, hot strength, and cold strength during the reduction process are tested. The reduction endpoint is set at 180 minutes. The test results are as follows: Figure 6 , Figure 7 , Figure 4 As shown.

[0043] like Figure 4As shown, comparing the hot and cold strength tests of the experimental group reveals that in the initial stage of reduction, the cold strength is significantly lower than the corresponding hot strength. However, as the reduction time increases, the cold strength in the later stages of reduction exceeds the corresponding hot strength. This differs from previous research, which generally holds that the cooling process should promote material shrinkage and densification, thereby improving strength. This invention further explores the underlying principles of the above research from a microstructural perspective.

[0044] The obtained samples were cooled with liquid nitrogen, nitrogen gas, and furnace in-flight cooling at reduction times of 30 min and 180 min, respectively. Their microstructures are as follows: Figure 5 As shown. Figure 5 The reduction times for a, b, and c are all 30 min. The microstructure diagrams are shown in order under liquid nitrogen cooling, nitrogen cooling, and furnace cooling methods. Figure 5 The reduction times for d, e, and f are all 180 min, and the microstructure diagrams are shown in order under liquid nitrogen cooling, nitrogen cooling, and furnace cooling methods. In the diagram, H indicates hematite, with the chemical composition Fe2O3, which is reddish-brown; M indicates magnetite, with the chemical composition Fe3O4, which is magnetic; P indicates pores, referring to tiny voids or cavities in the material; W indicates pseudomorphous hematite, an iron oxide with the chemical composition FeO; and Fe in the diagram refers to pure iron or elemental iron. Figure 5 It can be seen that the sample structure is relatively intact under liquid nitrogen quenching and nitrogen cooling, with the Fe2O3 surface gradually being coated by Fe3O4. However, the pellets cooled in the furnace show a large number of pores, indicating significant structural reconstruction during slow cooling. The transformation from Fe2O3 to Fe3O4 is accompanied by lattice expansion. Due to the difference in the shrinkage rates between phases, interfacial instability, bridging failure, and porosity expansion become... Figure 4 The main reason why the cold strength is lower than the hot strength in the early stage of reduction is that, in the later stage of reduction, metallic Fe has been formed. Even if a continuous bridging network has not yet formed at high temperature, the cooling process of the furnace causes the metallic Fe to shrink and densify, forming a dense bridging structure and reducing porosity, thus making... Figure 4 The cold-state strength is higher than the hot-state strength in the later stage of reduction.

[0045] In summary, different cooling methods can affect the results of cold strength tests, and the results of cold strength tests cannot truly reflect the mechanical state of pellets under high-temperature reducing conditions.

[0046] As a further preferred embodiment of the sample support 501, the contact surface between the sample and the sample in the sample support 501 is made of graphite material, which can improve the anti-adhesion performance of the sample support 501 and reduce the adhesion between it and the sample during the crushing process.

[0047] To improve the stability of the sample during the pressure application process, both the connecting column 503 and the sample support 501 are cylindrical structures.

[0048] Preferably, the connecting column 503 and the output end of the rotating unit 502 are connected by high-strength bolts, which helps to prevent the connecting column 503 from overturning during the pressure application process.

[0049] refer to Figure 1 As shown, the furnace chamber 301 resembles a cover, fitted onto the outer wall of the middle part of the connecting column 503, forming a relatively enclosed heating chamber between the connecting column 503 and the inner cavity of the furnace chamber 301. Specifically, the lower inner wall of the furnace chamber 301 is slidably fitted onto the outside of the connecting column 503. The heating unit 3 includes a lifting assembly 304, which is disposed outside the furnace chamber 301 and is used to drive the furnace chamber 301 to move vertically relative to the connecting column 503, thereby forming a heating chamber between the connecting column 503 and the inner cavity of the furnace chamber 301.

[0050] Specifically, the bottom of the lifting assembly 304 is fixedly installed on the frame 7, and the upper output end is fixedly connected to the top outer wall of the furnace 301 to drive the furnace 301 to move in the vertical direction.

[0051] It should be noted that the inner wall of the bottom of the furnace 301 and the outer wall of the connecting column 503 are equipped with corresponding sealing components to prevent gas in the furnace 301 from leaking from the gap between its inner wall and the outer wall of the connecting column 503.

[0052] refer to Figure 1 , Figure 2 As shown, in order to facilitate the driving of the pressure bar detection unit 1 during the pressing of the sample, the pressure bar detection unit 1 includes a force measuring component 101 and a force applying component 102. The force measuring component 101 is located outside the furnace chamber 301. The top of the force applying component 102 is connected to the force measuring component 101, and the bottom extends into the inner cavity of the furnace chamber 301 and is fixedly installed on the wall of the furnace chamber 301. That is, the force applying component 102 moves synchronously with the furnace chamber 301.

[0053] It should also be noted that there is more downward clearance between the inner wall of the bottom of the furnace 301 and the outer wall of the connecting column 503. Driven by the lifting assembly 304, the furnace 301 continues to descend relative to the connecting column 503, and the pressure bar detection unit 1 descends synchronously with the furnace 301, so that the pressure bar detection unit 1 can apply pressure to the sample in the sample carrier 501 and crush it.

[0054] As an extension, the force application component 102 includes a detachably connected pressure rod body 122 and pressure rod head 121. The pressure rod body 122 is made of corundum material, and the pressure rod head 121 is made of graphite material.

[0055] The pressure bar indenter 121 is made of graphite, which helps reduce adhesion between the sample and the pressure bar indenter 121. Meanwhile, the pressure bar body 122 is made of corundum, which can effectively ensure the overall mechanical strength of the force application component 102.

[0056] In some other embodiments, the detection platform also includes an observation unit 6, which includes a horizontally arranged observation channel 601. One end of the observation channel 601 extends into the inner cavity of the furnace 301 and faces the side wall of the lower part of the pressure rod detection unit 1, while the other end is located outside the furnace 301 and is fixedly installed on the furnace wall for observing the sample placed in the sample carrier 501.

[0057] An observation lens 602 is provided at one end of the observation channel 601 located outside the furnace 301. The observation lens 602 is used to observe the sample inside the furnace 301 through the observation channel 601, including the reduction process of the sample and the morphological changes during the pressure application process, which are mutually verified with the obtained compressive strength data.

[0058] To improve the temperature uniformity inside the furnace 301, the heating assembly includes a thermocouple 304 fixedly installed inside the furnace 301 and at least two vertically arranged silicon molybdenum rods 302. The at least two silicon molybdenum rods 302 are arranged in a circumferential array with the axis of the furnace 301 as the center, and the temperature measuring end of the thermocouple 304 is placed close to the sample placed in the sample carrier 501.

[0059] To improve the uniformity of the atmosphere inside the furnace 301, the gas distribution unit 4 includes a gas distribution cabinet 401 and multiple air supply channels 402 extending into the furnace 301. The gas distribution cabinet 401 is connected to multiple gas cylinders for supplying corresponding gases to the gas distribution cabinet 401. The gas distribution cabinet 401 is located outside the furnace 301, and its outlet end is connected to multiple air supply channels 402 for supplying gases to the air supply channels 402. The multiple air supply channels 402 are distributed at intervals along the circumferential direction with the axis of the furnace 301 as the center.

[0060] The in-situ testing platform for the hot strength of the furnace charge includes the following steps: a) placing the sample to be tested in the sample support 501, and then positioning the sample support 501 within the inner cavity of the furnace 301 to form a heating chamber between the connecting column 503 and the inner cavity of the furnace 301; b) continuously introducing an inert atmosphere into the furnace 301 through the gas distribution unit 4 at a flow rate of 5 L / min to 10 L / min, and heating the inner cavity of the furnace 301 by the heating assembly, raising the temperature to... After setting the temperature, maintain the temperature for 15-30 minutes to allow the sample to fully store heat. Then, a reducing atmosphere is continuously introduced into the furnace 301 through the gas distribution unit 4 at a flow rate of 10L / min-20L / min. c. After the set reduction time is reached, the rotating unit 502 moves the sample in the sample support 501 to the bottom of the pressure bar detection unit 1. The pressure bar detection unit 1 applies pressure to the sample placed in the sample support 501 and crushes it, recording the force value during the crushing process.

[0061] In step a, the number of test samples used is preferably 8 to 10, with the average cold strength controlled between 2500N and 2800N and the diameter selected between 12.5±0.5mm.

[0062] In step b, the inert atmosphere introduced into the furnace 301 by the gas distribution unit 4 is nitrogen. After the original gas inside is vented, the heating component starts heating. The reducing atmosphere introduced into the furnace 301 by the gas distribution unit 4 is 70% N2 + 30% CO.

[0063] In one specific hot strength test, the reduction time was 60 minutes, and eight sample support seats 501 were set up. Correspondingly, eight pellets were placed in the furnace 301. The test data are shown in Table 1. As can be seen from Table 1, the compressive strength fluctuation range of multiple samples in the same group is relatively small.

[0064]

[0065] Performance test comparison A control group was set up, the difference between which was the structure of the sample support. Specifically, the groove for placing the sample in the sample support was an arc-shaped groove that matched the lower outer surface of the pellet. The degree of reduction and hot strength of the pellet during the reduction process were tested using this arc-shaped groove. The reduction endpoint was set at 180 minutes. The test results for the degree of reduction and hot strength are as follows: Figure 6 , Figure 7 As shown.

[0066] Another set of pellets was set up as a standard group. The reduction degree of this standard group of pellets was measured according to the Chinese National Standard GB / T13241-2017 "Determination of Reducibility of Iron Ore". The reduction endpoint was set at 180 min. The results of the reduction degree test are detailed in [link to relevant documentation]. Figure 6 As shown.

[0067] like Figure 6 As shown, the reduction degree of the experimental group after 180 min of reduction was 63.1%, which is closer to the conversion rate of 64.4% measured in the standard group. This indicates that by improving the structure of the sample support 501, the reduction degree of the pellets is made closer to that measured in the standard group.

[0068] Combination Figure 4 It can be seen that as the reduction time increases, the degree of reduction continuously increases, while the overall thermal strength shows a continuous decreasing trend. From... Figure 7 It can be seen that during the test, the thermal intensity of the experimental group was generally lower than that of the control group. Figure 4 The observed patterns suggest that the experimental group achieved a more thorough and higher degree of reduction; compared to... Figure 6 The displayed fidelity data corresponds to...

[0069] The present invention and its embodiments have been described above illustratively. This description is not restrictive, and the figures shown are only one embodiment of the present invention; the actual structure is not limited thereto. Therefore, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the spirit of the present invention, such designs should fall within the protection scope of the present invention.

Claims

1. An in-situ testing platform for the hot strength of metallurgical furnace charge, characterized in that, include: Heating unit (3), the heating unit (3) includes furnace chamber (301), the inner cavity of the furnace chamber (301) is a vertical rotationally symmetrical cavity and is equipped with heating components; Gas distribution unit (4), which is used to provide the atmosphere required for the inner cavity of the furnace (301); Pressure bar detection unit (1), which extends from the outside of the furnace (301) to its inner cavity from top to bottom, is used to apply pressure to the sample inside the furnace (301) and detect the pressure. And a layout bearing unit (5), the layout bearing unit (5) includes a rotating unit (502) and a vertically arranged connecting column (503). The axis of the connecting column (503) coincides with the axis of the inner cavity of the furnace (301). The top of the connecting column (503) is located in the inner cavity of the furnace (301) and is provided with at least two sample bearing seats (501). The at least two sample bearing seats (501) are distributed at intervals along the circumferential direction with the axis of the inner cavity of the furnace (301) as the center. The bottom of the connecting column (503) extends to the outside of the furnace (301). The rotating unit (502) is used to drive the bottom of the connecting column (503) to rotate along its own axis, so as to drive at least two sample bearing seats (501) to move to the bottom of the pressure bar detection unit (1) respectively.

2. The in-situ testing platform for the hot strength of metallurgical furnace charge according to claim 1, characterized in that, The top of the sample support (501) is provided with a sample placement groove (511), which is a V-shaped groove with the opening facing upward and the opening angle being 140~150°.

3. The in-situ testing platform for the hot strength of metallurgical furnace charge according to claim 2, characterized in that, The sample support (501) protrudes from the top of the connecting column (503) and has a gas channel (512) extending toward and communicating with the V-shaped groove on its side wall.

4. The in-situ testing platform for the hot strength of metallurgical furnace charge according to claim 3, characterized in that, The number of gas channels (512) is at least two, and the at least two gas channels (512) are distributed at intervals along the circumferential direction with the axis of the sample carrier (501) as the center.

5. The in-situ testing platform for the hot strength of metallurgical furnace charge according to any one of claims 1-4, characterized in that, The inner wall of the lower part of the furnace chamber (301) is slidably sleeved on the outside of the connecting column (503). The heating unit (3) includes a lifting assembly (304), which is located outside the furnace chamber (301) and is used to drive the furnace chamber (301) to move in the vertical direction relative to the connecting column (503) to form a heating chamber between the connecting column (503) and the inner cavity of the furnace chamber (301).

6. The in-situ testing platform for the hot strength of metallurgical furnace charge according to claim 5, characterized in that, The pressure bar detection unit (1) includes a force measuring component (101) and a force applying component (102). The force measuring component (101) is located outside the furnace (301). The top of the force applying component (102) is connected to the force measuring component (101), and the bottom extends into the inner cavity of the furnace (301) and is fixedly installed on the furnace wall (301). The force applying component (102) includes a detachably connected pressure bar body (122) and a pressure bar head (121). The pressure bar body (122) is made of corundum material, and the pressure bar head (121) is made of graphite material.

7. The in-situ testing platform for the hot strength of metallurgical furnace charge according to claim 5, characterized in that, The testing platform also includes an observation unit (6), which includes a horizontally arranged observation channel (601). One end of the observation channel (601) extends into the inner cavity of the furnace (301) and faces the side wall of the lower part of the pressure bar testing unit (1). The other end is located outside the furnace (301) and is fixedly installed on the furnace wall (301) for observing the sample placed in the sample carrier (501).

8. The in-situ testing platform for the hot strength of metallurgical furnace charge according to claim 1, characterized in that, The heating assembly includes a thermocouple (304) fixedly installed in the inner cavity of the furnace (301) and at least two vertically arranged silicon molybdenum rods (302). The at least two silicon molybdenum rods (302) are arranged in a circumferential array with the axis of the furnace (301) as the center. The temperature measuring end of the thermocouple (304) is placed close to the sample placed in the sample carrier (501).

9. The in-situ testing platform for the hot strength of metallurgical furnace charge according to claim 1, characterized in that, The gas distribution unit (4) includes a gas distribution cabinet (401) and multiple air supply channels (402) extending into the inner cavity of the furnace (301). The gas distribution cabinet (401) is located outside the furnace (301), and its outlet end is connected to multiple air supply channels (402). The multiple air supply channels (402) are distributed at intervals along the circumferential direction with the axis of the inner cavity of the furnace (301) as the center.

10. A method for in-situ testing of the hot strength of metallurgical furnace charge, characterized in that, The detection method employs the in-situ detection platform for the hot strength of metallurgical furnace charge as described in any one of claims 1-9, and the method includes: The sample to be tested is placed in the sample carrier (501), and then the sample carrier (501) is located in the inner cavity of the furnace (301) to form a heating cavity between the connecting column (503) and the inner cavity of the furnace (301). An inert atmosphere is continuously introduced into the furnace (301) through the gas distribution unit (4) at a flow rate of 5L / min to 10L / min. The heating component heats the inner cavity of the furnace (301) and holds it at the set temperature for 15 to 30 minutes. Then, a reducing atmosphere is continuously introduced into the furnace (301) through the gas distribution unit (4). After the set reduction time is reached, the rotating unit (502) drives the sample in the sample carrier (501) to move sequentially to the bottom of the pressure bar detection unit (1). The pressure bar detection unit (1) applies pressure to the sample placed in the sample carrier (501) and crushes it, and records the force value during the crushing process.

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