Method for producing ferroboron pellets by accurately adjusting roasting temperature

Abstract

The invention relates to a method for producing ferroboron pellets by precisely adjusting the roasting temperature, and belongs to the technical field of metallurgy. The method comprises the steps that magnetite powder and paigeite powder are mixed, and a pre-ingredient is obtained; mixing the pre-prepared material with sodium bentonite to obtain a mixed material; sequentially carrying out drying and screening treatment on the mixed material; carrying out compression molding on the screened mixed material to obtain a cylindrical sample; the 5% shrinkage rate temperature T5 and the 10% shrinkage rate temperature T10 of the cylindrical sample are obtained; acquiring a 5% shrinkage rate temperature T5 reference and a 10% shrinkage rate temperature T10 reference of the standard sample; and comparing the shrinkage rate temperature of the standard sample with the shrinkage rate temperature of the cylindrical sample, and adjusting the roasting temperature during production of the ferroboron pellets based on a comparison result. According to the method, accurate adjustment of the roasting temperature is achieved, and the produced ferroboron pellets are low in cost, stable in performance and suitable for a blast furnace ironmaking process.

Description

Technical Field

[0001] This application relates to the field of metallurgical technology, and in particular to a method for producing boron-iron pellets by precisely adjusting the roasting temperature. Background Technology

[0002] In steel enterprises, cost control in the blast furnace ironmaking process plays a crucial role in improving economic efficiency and market competitiveness. Iron ore pellets, as a high-quality blast furnace feedstock, are increasingly used in blast furnace ironmaking due to their low energy consumption and minimal environmental pollution during production. However, raw material costs constitute a major portion of the production cost of iron ore pellets. Therefore, increasing the proportion of low-cost, high-performance iron ore powder used while ensuring pellet quality has become a key factor in improving the cost-effectiveness of iron ore pellets.

[0003] Boron-iron ore powder, as a low-cost mineral powder, has the potential to replace high-cost magnetic concentrate. The B2O3 component in boron-iron ore powder can react with various oxides to form solid solutions, lowering the melting point and thus increasing the liquid phase content during pellet roasting, enhancing fluidity, and improving the strength of the pellets. However, determining the appropriate roasting temperature to suit the oxidized pellet roasting process has become a pressing technical challenge. Excessively high temperatures may increase the reduction expansion rate of the pellets and reduce their compressive strength; excessively low temperatures may affect the melting and solidification of the pellets, also leading to substandard quality. Therefore, accurately controlling the suitable temperature range for oxidized pellet roasting through laboratory adjustments is crucial for improving the production quality and efficiency of boron-iron ore pellets.

[0004] Traditional methods for adjusting roasting temperature often rely on experience and repeated trials, lacking intuitiveness and precision. This approach is not only time-consuming and labor-intensive, but also struggles to guarantee optimal results with each adjustment. Therefore, developing a method for intuitively and precisely adjusting roasting temperature is crucial for improving the production quality and efficiency of ferroboron ore pellets. Summary of the Invention

[0005] This application provides a method for precisely adjusting the roasting temperature to produce ferroboron ore pellets, in order to solve the following technical problem: how to precisely control the roasting temperature when adding low-cost ferroboron ore powder, so as to produce ferroboron ore pellets of qualified quality. This application provides a method for precisely adjusting the roasting temperature to produce ferroboron ore pellets, the method comprising: Magnetite powder and boron ore powder are mixed to obtain a pre-mixed feedstock; The pre-mixed material is mixed with sodium bentonite to obtain a mixture. The mixture is then subjected to drying and sieving processes in sequence. The sieved mixture is pressed into a cylindrical sample. The temperatures at which the cylindrical sample exhibited 5% shrinkage (T5) and 10% shrinkage (T) were determined. 10 ; Temperature T for obtaining 5% shrinkage of standard samples 5基准 and temperature T with 10% shrinkage 10基准 ; The shrinkage temperatures of the standard sample and the cylindrical sample are compared, and the roasting temperature during the production of ferroboron pellets is adjusted based on the comparison results.

[0006] Optionally, the temperature T5 for obtaining the 5% shrinkage rate and the temperature T for obtaining the 10% shrinkage rate of the cylindrical sample are... 10 ,include: The cylindrical sample is heated and melted; When the shrinkage rate of the cylindrical sample is 5% and 10%, the corresponding temperatures T5 and T1 are recorded respectively. 10 .

[0007] Optionally, the temperature T at which the 5% shrinkage rate of the standard sample is obtained is... 5基准 and temperature T with 10% shrinkage 10基准 ,include: The standard sample is heated and melted; When the shrinkage rate of the standard sample is 5% and 10%, the corresponding temperature T is recorded respectively. 5基准 and T 10基准 .

[0008] Optionally, comparing the shrinkage temperatures of the standard sample and the cylindrical sample, and adjusting the roasting temperature during the production of ferroboron ore pellets based on the comparison results, includes: The temperature difference ΔT5 between the standard sample and the cylindrical sample at 5% shrinkage is obtained, where ΔT5 = T5reference - T5; The temperature difference ΔT between the standard sample and the cylindrical sample at 10% shrinkage was obtained. 10 ΔT 10 =T 10 Reference-T 10 ; The average temperature difference ΔT is obtained, ΔT = (ΔT₅ + ΔT) 10 ) / 2; When producing ferroboron ore pellets, the roasting temperature is adjusted up or down by ΔT based on the roasting temperature of the production line.

[0009] Optionally, in the production of ferroboron ore pellets, the roasting temperature is adjusted upward or downward by ΔT based on the production line roasting temperature, including: If ΔT is positive, when producing boron-iron pellets, the roasting temperature is reduced by ΔT based on the production line roasting temperature. If ΔT is negative, when producing ferroboron pellets, the roasting temperature is increased by ΔT based on the production line roasting temperature. Optionally, the pre-mixed materials, by mass fraction, are: magnetite powder: 95%–99%, boronite powder: 1%–5%.

[0010] Optionally, the mass ratio of the pre-mixed material to the sodium bentonite is 100:(1-2).

[0011] Optionally, the particle size of the mixture after sieving is <200 mesh.

[0012] Optionally, the mass of the cylindrical sample is 2g to 3g.

[0013] Optionally, the pressing pressure is 5MPa to 10MPa, and the pressing time is 5min to 10min.

[0014] The technical solutions provided in this application have the following advantages compared with the prior art: This application provides a method for precisely adjusting the roasting temperature to produce boron-iron ore pellets. The method includes: mixing magnetite powder and boron-iron ore powder to obtain a pre-mixed material; mixing the pre-mixed material with sodium bentonite to obtain a mixed material; drying and sieving the mixed material sequentially; pressing the sieved mixed material into cylindrical samples; heating and melting the cylindrical samples; and recording the corresponding temperatures T5 and T6 when the shrinkage rate of the cylindrical samples is 5% and 10%, respectively. 10 The standard sample was heated and melted; when the shrinkage rate of the standard sample was 5% and 10%, the corresponding temperature T was recorded. 5基准 and T 10基准 The shrinkage temperatures of the standard sample and the cylindrical sample are compared, and the roasting temperature for producing ferroboron ore pellets is adjusted based on the comparison results. This method achieves precise control of the roasting temperature. After adjusting the roasting temperature through the above steps, the produced ferroboron ore pellets have a compressive strength ≥3000N and a reduction expansion rate ≤15%. Such ferroboron ore pellets are not only low in cost but also have stable performance, making them suitable for blast furnace ironmaking processes. Attached Figure Description The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0015] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic flowchart illustrating a method for precisely adjusting roasting temperature to produce ferroboron pellets, as provided in an embodiment of this application. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0018] The range descriptions used herein, such as numerical ranges and proportional ranges, include all possible sub-ranges and single numerical values ​​within that range. For example, the range descriptions of "1 to 6" or "1~6" cover all sub-ranges (such as 1 to 3, 2 to 5, etc.) and single numbers (such as 1, 2, 3, 4, 5, 6) between 1 and 6. Unless otherwise specified, the terms "including" and "contains" as used herein mean "including but not limited to"; relational terms such as "first" and "second" are used only to distinguish different entities or operations and do not imply an actual order or relationship; "and / or" indicates that multiple situations can exist individually or simultaneously; expressions such as "at least one," "multiple," and "at least one" refer to any combination of the corresponding objects, including combinations of single or multiple objects. The proportional relationships mentioned herein, such as mass ratios and molar ratios, should be understood as the correspondence between the first and second terms of a proportional formula, according to the order of description. The raw materials, reagents, instruments, and equipment used herein can all be obtained through commercial purchase or prepared using existing methods.

[0019] Figure 1 This is a schematic flowchart illustrating a method for precisely adjusting roasting temperature to produce ferroboron pellets, as provided in an embodiment of this application.

[0020] like Figure 1 As shown in the embodiment of this application, a method for precisely adjusting the roasting temperature to produce ferroboron ore pellets is provided, the method comprising: S1. Mix magnetite powder and boron ore powder to obtain a pre-mixed feedstock; In some embodiments, the pre-mixed materials, by mass fraction, are: magnetite powder: 95%–99%, boronite powder: 1%–5%.

[0021] In the pre-mixed feedstock, magnetite powder accounts for 95%–99%, and boron ore powder accounts for 1%–5%. The core purpose is to optimize cost and energy consumption while ensuring the feasibility and quality of pellet production. For example, the mass fraction of magnetite powder can be 95%, 96%, 97%, 98%, 99%, etc., and the mass fraction of boron ore powder can be 1%, 2%, 3%, 4%, 5%, etc.

[0022] S2. Mix the pre-mixed material with sodium bentonite to obtain a mixture. In some embodiments, the mass ratio of the pre-mixed material to the sodium bentonite is 100:(1-2).

[0023] Sodium bentonite, used as a binder, primarily functions to improve the strength and drop strength of green pellets, ensuring the integrity of the pellets during subsequent roasting. For example, the mass ratio of pre-mixed feedstock to sodium bentonite can be 100:1, 100:1.2, 100:1.4, 100:1.6, 100:1.8, 100:2, etc.

[0024] S3. The mixture is dried and sieved sequentially. In this embodiment, the mixture can be placed in a constant temperature oven for thorough drying. The oven temperature can be 105°C and the drying time can be 24 hours. After drying, the mixture needs to be sieved to remove coarse particles, ensuring that the sample particle size is consistent and avoiding uneven density of the molded sample due to particle differences, which would affect the accuracy of the melt shrinkage characteristic measurement.

[0025] In some embodiments, the particle size of the mixture after sieving is <200 mesh.

[0026] Fine-grained mineral powder (<200 mesh) is easy to form dense cylindrical samples during pressing, which reduces the interference of porosity on the monitoring of changes in melt height. At the same time, it simulates the process conditions of fine grinding of raw materials in industrial pellet production, ensuring the consistency between experimental results and actual production.

[0027] S4. Press the sieved mixture into a cylindrical sample. In some embodiments, the pressing pressure is 5 MPa to 10 MPa, and the pressing time is 5 min to 10 min.

[0028] In this embodiment, the mixture can be molded into a cylindrical sample with a diameter of 8 mm and a height of 10 mm by using a mold and a tablet press under a pressure of 5 MPa to 10 MPa for 5 to 10 minutes. The pressure range of 5 MPa to 10 MPa in this embodiment balances the sample's density with the mold's safety. When the pressure is less than 5 MPa, the sample has high internal porosity and unstable shrinkage behavior during melting; when the pressure is greater than 10 MPa, it may cause mold deformation or sample cracking. For example, the pressing pressure can be 5 MPa, 6 MPa, 7 MPa, 8 MPa, 9 MPa, 10 MPa, etc. The 5 to 10 minutes ensures that the pressure is fully transmitted to the interior of the sample, allowing the mineral powder particles to come into close contact and forming a cylindrical sample with a uniform structure. For example, the pressing time can be 5 minutes, 6 minutes, 7 minutes, 8 minutes, 9 minutes, 10 minutes, etc.

[0029] In some embodiments, the mass of the cylindrical sample is 2g to 3g.

[0030] For example, the mass of the cylindrical sample can be 2g, 2.2g, 2.4g, 2.6g, 2.8g, 3g, etc.

[0031] S5. Obtain the 5% shrinkage temperature T5 and the 10% shrinkage temperature T of the cylindrical sample. 10 ; In some embodiments, the temperature T5 for obtaining the 5% shrinkage rate and the temperature T10 for obtaining the 10% shrinkage rate of the cylindrical sample are... 10 ,include: The cylindrical sample is heated and melted; When the shrinkage rate of the cylindrical sample is 5% and 10%, the corresponding temperatures T5 and T1 are recorded respectively. 10 .

[0032] The initial height of the cylindrical sample is recorded as h1. During the heating and melting process, the heights are recorded as h2 and h3. The shrinkage characteristics are determined by the rate of change of height: when the height of the cylindrical sample shrinks to 95% of its original height (i.e., h2 / h1 = 95%, shrinkage rate 5%), the temperature at this point is recorded as T5. Based on the height h2 corresponding to T5, when the sample height further shrinks to 90% of h2 (i.e., h3 / h2 = 90%, shrinkage rate 10%), the temperature at this point is recorded as T. 10 .

[0033] S6. Obtain the temperature T at which the standard sample reaches 5% shrinkage. 5基准 and temperature T with 10% shrinkage 10基准 ; In this embodiment, the standard sample is a sample without added boron ore powder (the amount of boron ore powder added is 0%), and its preparation process is consistent with that of the cylindrical sample to be tested (containing boron ore powder) to ensure the consistency of the test conditions.

[0034] In some embodiments, the temperature T at which the 5% shrinkage rate of the standard sample is obtained is... 5基准 and temperature T with 10% shrinkage 10基准 ,include: The standard sample is heated and melted; When the shrinkage rate of the standard sample is 5% and 10%, the corresponding temperature T is recorded respectively. 5基准 and T 10基准 .

[0035] The prepared standard sample (pretreated under the same conditions as the cylindrical sample, including pressing and drying) was heated and melted to simulate the temperature changes during actual calcination. When the standard sample shrank to 95% of its original height during heating (i.e., a shrinkage rate of 5%), the temperature at this point was recorded as T5. Based on this 5% shrinkage, the standard sample height was further shrank to 90% of its original height, and the temperature at this point was recorded as T5. 10 Benchmark.

[0036] During the heating and melting process of the standard sample (without borax ore powder) and the cylindrical sample (control sample), an air atmosphere was used throughout to simulate the oxidation environment during the roasting of industrial pellets (the oxidation of magnetite powder to hematite in air is one of the main reactions in roasting and consolidation), ensuring that the experimental conditions were consistent with actual production. In this embodiment, the heating and melting process can be carried out at a heating rate of 10℃ / min to 1050℃, and then continuously heated at a heating rate of 5℃ / min until the sample melts, in order to accurately capture the key shrinkage nodes of the sample (temperatures T5 and T6 corresponding to 5% and 10% shrinkage rates). 10 This helps avoid temperature measurement errors caused by excessively rapid heating.

[0037] S7. Compare the shrinkage temperature of the standard sample and the cylindrical sample, and adjust the roasting temperature when producing boron-iron pellets based on the comparison results.

[0038] In some embodiments, comparing the shrinkage temperatures of the standard sample and the cylindrical sample, and adjusting the roasting temperature during the production of ferroboron ore pellets based on the comparison results, includes: The temperature difference ΔT5 between the standard sample and the cylindrical sample at 5% shrinkage is obtained, where ΔT5 = T5reference - T5; The temperature difference ΔT between the standard sample and the cylindrical sample at 10% shrinkage was obtained. 10 ΔT 10 =T10 Reference-T 10 ; The average temperature difference ΔT is obtained, ΔT = (ΔT₅ + ΔT) 10 ) / 2; When producing ferroboron ore pellets, the roasting temperature is adjusted up or down by ΔT based on the roasting temperature of the production line.

[0039] The production line roasting temperature refers to the reference temperature used to adjust the roasting temperature of ferroboron ore pellets on an industrial production line. Specifically, it is the roasting temperature of pellets with added ferroboron ore powder under the original production process. In the embodiments of this application, by measuring the shrinkage temperature difference ΔT between a cylindrical sample (the sample with added ferroboron ore powder) and a standard sample, the roasting temperature during the actual production of ferroboron ore pellets is adjusted upward or downward based on the production line roasting temperature, thereby achieving precise temperature control for the production of qualified ferroboron ore pellets.

[0040] In some embodiments, during the production of ferroboron ore pellets, the roasting temperature is adjusted upward or downward by ΔT based on the production line roasting temperature, including: If ΔT is positive, when producing boron-iron pellets, the roasting temperature is reduced by ΔT based on the production line roasting temperature. If ΔT is negative, when producing ferroboron pellets, the roasting temperature is increased by ΔT based on the production line roasting temperature. If ΔT is positive (a common situation in practical applications): the melting temperature of the control sample is lower than that of the standard sample, so the roasting temperature ΔT needs to be reduced to match its early melting characteristics and avoid over-burning, which would lead to a decrease in the strength of the pellets or an excessive reduction expansion rate.

[0041] If ΔT is negative (theoretical extreme case, with extremely low boron iron ore powder addition or abnormal raw material composition): the melting temperature of the control sample is higher than that of the standard sample, and the roasting temperature ΔT needs to be increased to ensure that it is fully melted and solidified.

[0042] The present application is further illustrated below with reference to specific embodiments. Experimental methods in the following embodiments that do not specify specific conditions are generally determined according to national / industry standards; if there is no corresponding national / industry standard, they are performed according to general international standards, conventional conditions, or conditions recommended by the manufacturer.

[0043] Example 1 Preparation of standard samples: Step 1: Raw material preparation: The mass ratio of magnetite powder to sodium bentonite is 100:1.8.

[0044] Step 2, Mixing and Drying: Mix magnetite powder and bentonite thoroughly to obtain a mixture; The mixture was placed in a constant temperature oven and dried at 105℃ for 24 hours; after drying, the mixture was sieved to a particle size of less than 200 mesh to obtain the sample. Step 3, molding: Take 2.1g of sample and use a mold and tablet press to maintain the pressure at 5MPa for 6 minutes to mold it into a cylindrical sample with a diameter of 8mm and a height of 10mm.

[0045] Step 4, Determination of sintering and melting characteristics: The cylindrical sample is placed in a micro sintering machine and heated to 1050°C at a heating rate of 10°C / min in an air atmosphere, and then heated continuously at a heating rate of 5°C / min until the sample melts.

[0046] Step 5: Observe the sample height change using a camera and record the initial height h1. When the sample height drops to h2 and h2 / h1 = 95%, record this as a 5% shrinkage rate, and record the temperature at this point as T51. Continue heating. When the sample height drops from h2 to h3 and h3 / h2 = 90%, record this as a 10% shrinkage rate, and record the temperature at this point as T101. Record the values ​​of T51 and T101. Since this sample is a standard sample, there is no need to calculate ΔT5 and ΔT10.

[0047] Standard samples T51 = 1440℃, T101 = 1460℃.

[0048] The prepared pellets have a compressive strength of 3056 N and a reduction expansion rate of 12.74%.

[0049] Preparation of control samples: Step 1: Raw material preparation: In the pre-mixed materials, the mass fraction of magnetite powder is 99% and the mass fraction of boron ore powder is 1%.

[0050] The mass ratio of the premixed material to sodium bentonite is 100:1.5.

[0051] Steps 2 to 4: Same as in Example 1, obtain cylindrical samples and measure their melting characteristics.

[0052] Step 5: Observe the change in sample height using a camera and record the initial height h1. When the sample height drops to h2 and h2 / h1 = 95%, record this as a 5% shrinkage rate, and record the temperature at this point as T52. Continue heating, and when the sample height drops from h2 to h3 and h3 / h2 = 90%, record this as a 10% shrinkage rate, and record the temperature at this point as T102.

[0053] T52 =1427℃, T102 =1453℃.

[0054] Calculate ΔT5 = T51 - T52 = 13℃, ΔT10 = T101 - T102 = 7℃.

[0055] Adjust the roasting temperature ΔT = (ΔT5 + ΔT10) / 2 = 10℃.

[0056] Therefore, the roasting temperature of the boron-iron pellets for the control sample should be reduced by 10°C from the roasting temperature of the production line.

[0057] Step 6: Adjust the roasting temperature according to the calculated ΔT to produce boron-iron ore pellets for the control sample.

[0058] The compressive strength of the boron-iron pellets in the control sample was 3187 N, and the reduction expansion rate was 14.33%.

[0059] Example 2 Preparation of standard samples: Step 1: Raw material preparation: The mass ratio of magnetite powder to sodium bentonite is 100:1.8.

[0060] Step 2, Mixing and Drying: Mix magnetite powder and bentonite thoroughly to obtain a mixture; The mixture was placed in a constant temperature oven and dried at 105℃ for 24 hours; after drying, the mixture was sieved to a particle size of less than 200 mesh to obtain the sample. Step 3, molding: Take 2.1g of sample and use a mold and tablet press to maintain the pressure at 5MPa for 6 minutes to mold it into a cylindrical sample with a diameter of 8mm and a height of 10mm.

[0061] Step 4, Determination of sintering and melting characteristics: The cylindrical sample is placed in a micro sintering machine and heated to 1050°C at a heating rate of 10°C / min in an air atmosphere, and then heated continuously at a heating rate of 5°C / min until the sample melts.

[0062] Step 5: Observe the sample height change using a camera and record the initial height h1. When the sample height drops to h2 and h2 / h1 = 95%, record this as a 5% shrinkage rate, and record the temperature at this point as T51. Continue heating. When the sample height drops from h2 to h3 and h3 / h2 = 90%, record this as a 10% shrinkage rate, and record the temperature at this point as T101. Record the values ​​of T51 and T101. Since this sample is a standard sample, there is no need to calculate ΔT5 and ΔT10.

[0063] Standard samples T51 = 1440℃, T101 = 1460℃.

[0064] The prepared pellets have a compressive strength of 3056 N and a reduction expansion rate of 12.74%.

[0065] Preparation of control samples: Step 1: Raw material preparation: In the pre-mixed materials, the mass fraction of magnetite powder is 97% and the mass fraction of boron ore powder is 3%.

[0066] The mass ratio of the premixed material to sodium bentonite is 100:1.5.

[0067] Steps 2 to 4: Same as in Example 1, obtain cylindrical samples and measure their melting characteristics.

[0068] Step 5: Observe the change in sample height using a camera and record the initial height h1. When the sample height drops to h2 and h2 / h1 = 95%, record this as a 5% shrinkage rate, and record the temperature at this point as T52. Continue heating, and when the sample height drops from h2 to h3 and h3 / h2 = 90%, record this as a 10% shrinkage rate, and record the temperature at this point as T102.

[0069] T52 =1416℃, T102 =1444℃.

[0070] Calculate ΔT5 = T51 - T52 = 24℃, ΔT10 = T101 - T102 = 16℃.

[0071] Adjust the roasting temperature ΔT = (ΔT5 + ΔT10) / 2 = 20℃.

[0072] Therefore, the roasting temperature of the boron-iron pellets for the control sample should be reduced by 20°C from the roasting temperature of the production line.

[0073] Step 6: Adjust the roasting temperature according to the calculated ΔT to produce boron-iron ore pellets for the control sample.

[0074] The compressive strength of the boron-iron pellets in the control sample was 3375 N, and the reduction expansion rate was 14.19%.

[0075] Example 3 Preparation of standard samples: Step 1: Raw material preparation: The mass ratio of magnetite powder to sodium bentonite is 100:1.8.

[0076] Step 2, Mixing and Drying: Mix magnetite powder and bentonite thoroughly to obtain a mixture; The mixture was placed in a constant temperature oven and dried at 105℃ for 24 hours; after drying, the mixture was sieved to a particle size of less than 200 mesh to obtain the sample. Step 3, molding: Take 2.1g of sample and use a mold and tablet press to maintain the pressure at 5MPa for 6 minutes to mold it into a cylindrical sample with a diameter of 8mm and a height of 10mm.

[0077] Step 4, Determination of sintering and melting characteristics: The cylindrical sample is placed in a micro sintering machine and heated to 1050°C at a heating rate of 10°C / min in an air atmosphere, and then heated continuously at a heating rate of 5°C / min until the sample melts.

[0078] Step 5: Observe the sample height change using a camera and record the initial height h1. When the sample height drops to h2 and h2 / h1 = 95%, record this as a 5% shrinkage rate, and record the temperature at this point as T51. Continue heating. When the sample height drops from h2 to h3 and h3 / h2 = 90%, record this as a 10% shrinkage rate, and record the temperature at this point as T101. Record the values ​​of T51 and T101. Since this sample is a standard sample, there is no need to calculate ΔT5 and ΔT10.

[0079] Standard samples T51 = 1440℃, T101 = 1460℃.

[0080] The prepared pellets have a compressive strength of 3056 N and a reduction expansion rate of 12.74%.

[0081] Preparation of control samples: Step 1: Raw material preparation: In the pre-mixed materials, the mass fraction of magnetite powder is 95% and the mass fraction of boron ore powder is 5%.

[0082] The mass ratio of the premixed material to sodium bentonite is 100:1.5.

[0083] Steps 2 to 4: Same as in Example 1, obtain cylindrical samples and measure their melting characteristics.

[0084] Step 5: Observe the change in sample height using a camera and record the initial height h1. When the sample height drops to h2 and h2 / h1 = 95%, record this as a 5% shrinkage rate, and record the temperature at this point as T52. Continue heating, and when the sample height drops from h2 to h3 and h3 / h2 = 90%, record this as a 10% shrinkage rate, and record the temperature at this point as T102.

[0085] T52 =1407℃, T102 =1433℃.

[0086] Calculate ΔT5 = T51 - T52 = 33℃, ΔT10 = T101 - T102 = 27℃.

[0087] Adjust the roasting temperature ΔT = (ΔT5 + ΔT10) / 2 = 30℃.

[0088] Therefore, the roasting temperature of the boron-iron pellets for the control sample should be reduced by 30°C from the roasting temperature of the production line.

[0089] Step 6: Adjust the roasting temperature according to the calculated ΔT to produce boron-iron ore pellets for the control sample.

[0090] The compressive strength of the boron-iron pellets in the control sample was 3578 N, and the reduction expansion rate was 14.72%.

[0091] Furthermore, one or more technical solutions in the embodiments of the present invention have at least the following technical effects or advantages: This invention provides a method for visually adjusting the roasting temperature by observing the melting temperature of the ore powder, thereby producing qualified ferroboron ore pellets. This method allows for precise control of the roasting temperature, ensuring stable quality of the pellets.

[0092] The ferroboron pellets produced by the method of this invention have excellent physical properties, with a compressive strength ≥3000N and a reduction expansion rate ≤15%, which meets the high-quality requirements of blast furnace ironmaking for raw materials.

[0093] The addition of boron ore powder can lower the roasting temperature, resulting in qualified pellets at a lower roasting temperature, thereby reducing the energy consumption of the process.

[0094] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed in this application.

Claims

1. A method for producing boron-iron pellets by precisely adjusting the roasting temperature, characterized by, The method comprises: mixing magnetite powder and boron ore powder to obtain pre-blended material; mixing the pre-blended material with sodium bentonite to obtain mixed material; sequentially drying and screening the mixed material; compressing the screened mixed material to obtain cylindrical sample; obtaining a 5% shrinkage temperature T5 and a 10% shrinkage temperature T10 of the cylindrical sample 10 ; Obtaining the temperature T of 5% shrinkage of the standard sample 5基准 and the temperature T of 10% shrinkage 10基准 ; comparing the shrinkage temperature of the standard sample and the cylindrical sample, and adjusting the roasting temperature for producing boron iron pellet based on the comparison result.

2. The method of claim 1, wherein, said obtaining a 5% shrinkage temperature T5 and a 10% shrinkage temperature T10 of the cylindrical sample 10 comprising: melting the cylindrical sample by heating; When the shrinkage of the cylindrical sample is 5% and 10%, the corresponding temperatures T5 and T 10 are recorded, respectively.

3. The method of claim 1, wherein, the 5% shrinkage temperature T of the standard sample 5基准 and the 10% shrinkage temperature T 10基准 comprising: melting the standard sample by heating; When the shrinkage of the standard sample is 5% and 10%, the corresponding temperatures T 5基准 and T 10基准 are recorded, respectively.

4. The method of claim 1, wherein, the comparing the shrinkage temperature of the standard sample and the cylindrical sample, and adjusting the roasting temperature for producing boron iron pellet based on the comparison result comprises: obtaining the difference ΔT5 between the 5% shrinkage temperature of the standard sample and the cylindrical sample, ΔT5=T5 reference -T5; obtaining a difference in temperature of shrinkage of 10% ΔT between the standard sample and the cylindrical sample 10 , ΔT 10 = T 10 reference - T 10 ; The average temperature difference ΔT is obtained, ΔT = (ΔT5+ ΔT 10 ) / 2; for producing boron iron pellet, adjusting the roasting temperature by ΔT based on the production line roasting temperature.

5. The method of claim 4, wherein, the adjusting the roasting temperature for producing boron iron pellet based on the production line roasting temperature by ΔT comprises: if ΔT is positive, reducing the roasting temperature by ΔT based on the production line roasting temperature for producing boron iron pellet; if ΔT is negative, increasing the roasting temperature by ΔT based on the production line roasting temperature for producing boron iron pellet.

6. The method of claim 1, wherein, the pre-blended material comprises, by mass fraction, 95%-99% of magnetite powder and 1%-5% of boron ore powder.

7. The method of claim 1, wherein, the mass ratio of the pre-blended material to the sodium bentonite is 100: (1-2).

8. The method of claim 1, wherein, the particle size of the screened mixed material is <200 mesh.

9. The method of claim 1, wherein, the mass of the cylindrical sample is 2g-3g.

10. The method of claim 1, wherein, the compression pressure for the compression molding is 5MPa-10MPa, and the compression time for the compression molding is 5min-10min.

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