Method for analyzing mineralization performance of sintered mixture by adopting pre-sintering and mineral phase detection

Abstract

The invention discloses a novel method for improving air permeability of a blast furnace soft melting zone and reducing metallurgical coke consumption, and belongs to the technical field of blast furnace ironmaking. According to the method, the metallogenic properties of various gradient sintering mixtures are tested in advance before sintering cup test and sintering production by adopting a mode of combining tabletting pre-sintering and mineral phase detection, and a sintering mixture matching scheme which is more suitable for the current sintering material condition is selected. The specific technical thought is as follows: finely grinding and drying various raw and auxiliary materials; preparing a mixed material, and pressing the mixed material into a round cake; and sintering the round cake in a furnace, taking out the round cake, and naturally air-cooling the round cake. And finally, preparing a sample, detecting and analyzing the proportions of calcium ferrite, magnetite, hematite, a glass phase and pores, and evaluating the mineralization performance of the calcium ferrite, the magnetite, the hematite, the glass phase and the pores. The sintering test process is simple, the single test material consumption is extremely low, the sample preparation is convenient, parameters in the test process are stably controlled, the chemical components of the mixture are uniform, and the mineralization performance of the mixture with different mineral powder types and proportions can be accurately analyzed.

Description

Technical Field

[0001] The invention relates to the field of metallurgy, and in particular to a method for analyzing the mineralization performance of a sintered mixture by pre-sintering and mineral phase detection. Background Art

[0002] The clinker for domestic blast furnaces is mainly sintered ore, and the charge structure is basically "70% sintered ore + 25% pellets + 5% lump ore". In recent years, with the advancement of ironmaking technology, the proportion of pellets entering domestic blast furnaces has increased year by year, but sintered ore still occupies a major position. In the process of technical research and production practice in the field of sintering, the improvement of sintered ore quality and the increase in sintering machine output are all achieved on the basis of sintering cup test. Sintering cup test refers to the use of cup-shaped small test equipment to simulate production conditions for iron ore sintering test. Through the sintering cup test, the consolidation mechanism and mathematical model of sintered ore can be studied to improve the process and increase the output and quality of sintered ore. The sintering cup test can also be used to study new raw materials and new processes. However, the traditional sintering cup test method not only takes a long time, consumes a lot of materials, but also has high costs. At the same time, because the sintering cup test is a hundred-kilogram test, some sintering process parameters are difficult to control accurately. It is more suitable for simulating actual production and providing process parameters for it. However, it is more restricted when conducting mechanism research and the test results are not ideal.

[0003] To solve the above problems, the University of Science and Technology Beijing has designed a micro sintering test device that can simulate the sintering production process. It can simulate the sintering process by controlling the temperature and atmosphere. However, this method requires the customization of special equipment, and can only complete one set of tests at a time. The purchase of equipment increases cost expenditures, and existing equipment cannot be used well to serve on-site production. The equipment design also does not effectively improve the test efficiency. It is only suitable for scientific research and cannot serve on-site production in real time.

[0004] In summary, in order to effectively improve the efficiency of the sintering cup test, avoid additional expenses, and effectively utilize existing equipment, the present invention has been proposed and verified. The present invention adopts pre-sintering + mineral phase detection to analyze the mineralization performance of the sintering mixture, which is used to evaluate and predict the mineralization performance of the mixture during the sintering process. The mineralization performance of various gradient sintering mixtures is tested in advance before the sintering cup test and sintering production. The material consumption of a single test is extremely small, and the sample preparation is convenient. Multiple groups of tests can be carried out at the same time, and the control of various parameters during the test process is stable, and the chemical composition of the mixture is uniform. The sintering mixture formulation scheme that is more suitable for the current sintering material conditions is selected with high efficiency and low cost.

[0005] The purpose of the present invention is to develop a new method for analyzing the mineralization performance of sintered mixed materials by pre-sintering + mineral phase detection, which is used to evaluate and predict the mineralization performance of mixed materials in the sintering process. Summary of the invention

[0006] The purpose of the present invention is to solve the above problems and provide a method for analyzing the mineralization performance of sintered mixture by pre-sintering and mineral phase detection.

[0007] The object of the present invention is achieved in this way: a method for analyzing the mineralization performance of sintered mixed materials by pre-sintering and mineral phase detection, comprising the following steps: step 1: finely grinding the raw and auxiliary materials, the proportion of the finely ground particle size <200 mesh is greater than 90%, and the finely ground raw and auxiliary materials are placed in a drying oven for drying; step 2: detecting the chemical composition of the raw and auxiliary materials, including: the mass proportion of TFe, SiO2, CaO, MgO, and Al2O3 in iron ore concentrate, sintering return ore, blast furnace return ore, and purchased ore powder, and the mass proportion of white ash and the mass proportion of SiO2, CaO, MgO, and Al2O3 in dolomite; Step 3: weigh and mix the raw and auxiliary materials according to the designed ratio. After weighing, the lime needs to be digested with water and dried again. The drying temperature is 105°C and the time is 2h. Put the weighed and mixed mixture into a mortar and mix it thoroughly. Add 3~5% deionized water to the mixed mixture, and use a press to press the mixture into a round cake with a specification of φ16mm×10mm. The sample making pressure is 1.2kN / cm 2 , and the final holding time is 20s; Step 4: Heat the muffle furnace to 1230~1250℃, the atmosphere is air, place the prepared round cake on the platinum pad, put the round cake into the muffle furnace, and keep the constant temperature for 5~10min. After the constant temperature ends, take out the round cake and place it in the air to cool naturally; Step 5: After inlaying and polishing the round cake, place it under an optical microscope for mineral phase detection and analysis, and calculate the proportions of calcium ferrite, magnetite, hematite, glass phase and pores respectively.

[0008] In step 1, drying is performed in a drying oven at a temperature of 105° C. for 2 h.

[0009] The beneficial effects of the present invention are as follows: the present invention adopts a method combining tablet pre-sintering with mineral phase detection, and tests the mineralization properties of various gradient sintering mixtures in advance before the sintering cup test and sintering production, so as to further select a sintering mixture formulation scheme that is more suitable for the current sintering material conditions. The present invention has the following characteristics relative to micro-sintering and sintering cup tests: First, compared with the micro-sintering test process, it is simpler and does not require the purchase of additional dedicated test equipment. The laboratory is equipped with a high-temperature furnace and a mineral phase optical microscope to analyze and predict the mineralization properties of the sintering mixture; second, compared with the sintering cup test, the material consumption of a single test is extremely small and the sample preparation is convenient. At the same time, it avoids the influence of factors such as unstable sintering parameter control and uneven distribution of chemical composition of the mixture on the sintering process during the sintering cup test, and can more accurately study and analyze the mineralization properties of mixtures with different types and proportions of ore powders. DETAILED DESCRIPTION

[0010] The technical scheme of the present invention is as follows: 1. Grind various raw and auxiliary materials finely to ensure that the proportion of particle size <200 mesh is greater than 90%, and then put various raw and auxiliary materials into a drying oven for drying for 2 hours.

[0011] 2. Test the chemical composition of various raw and auxiliary materials: including the proportion of TFe, SiO2, CaO, MgO, Al2O3, etc. in iron ore powder such as iron ore concentrate, sintering return ore, blast furnace return ore, and purchased ore powder; the proportion of SiO2, CaO, MgO, Al2O3, etc. in lime and dolomite.

[0012] 3. Weigh and mix all kinds of raw materials and auxiliary materials according to the designed proportion (after weighing, the lime needs to be digested with water and dried again), and then put the mixture into a mortar and mix it thoroughly. Add an appropriate amount of deionized water (3~5% of the total mass of water and mixture) to the mixed mixture to enhance its molding ability. Use a sample press to press the mixture into round cakes with a specification of φ16mm×10mm. The specifications and mass of the round cakes in different test groups should be kept the same. The sample preparation pressure is 1.2kN / cm 2 , holding time is 20s.

[0013] 4. Heat the muffle furnace to 1230~1250℃, with air as the atmosphere. Place the prepared sample on a platinum pad, then put it into the muffle furnace and keep the temperature constant for 5~10 minutes. After the constant temperature is reached, take out the sample and place it in the air to cool naturally.

[0014] 5. The samples are mounted, polished, and placed under an optical microscope for mineral phase detection and analysis. The proportions of calcium ferrite, magnetite, hematite, glass phase, and pores are calculated respectively to predict and evaluate the mineralization performance of the mixture during the sintering process.

[0015] Before the following examples are tested, all kinds of raw and auxiliary materials are first finely ground to ensure that the proportion of particles <200 mesh is greater than 90%, and then all kinds of raw and auxiliary materials are placed in a drying oven for drying for 2 hours. After drying, samples are taken to detect the chemical composition of various raw and auxiliary materials: the proportion of TFe, SiO2, CaO, MgO, Al2O3, etc. in iron ore powder such as iron concentrate, sintering return ore, blast furnace return ore, and purchased ore powder; the proportion of SiO2, CaO, MgO, Al2O3, etc. in lime and dolomite.

[0016] Example 1 (Alkalinity)

[0017] In this embodiment, by adjusting the proportions of various raw and auxiliary materials, stabilizing the contents of Al2O3 and MgO, and regulating the amount of lime, a sintering mixture with four gradients of binary basicity ranging from 1.90 to 2.20 is obtained.

[0018]

[0019] Add water to the lime to digest and dry again, then put all kinds of raw and auxiliary materials into the drying oven for drying for 2 hours. This is to facilitate the subsequent control of the moisture content of the mixture. Weigh all kinds of raw and auxiliary materials according to the designed ratio. After weighing, the lime needs to be digested with water and dried again, then mixed and the mixture is put into a mortar to mix thoroughly. Add an appropriate amount of deionized water (3~5%) to the mixed mixture to enhance its molding ability. Use a sample press to press the mixture into a round cake with a specification of φ16mm×10mm, and the sample making pressure is 1.2kN / cm 2 , holding time is 20s.

[0020] Heat the muffle furnace to 1230℃, and the atmosphere is air. Place the prepared sample on a platinum pad, and then put it into the muffle furnace and keep it at a constant temperature for 8 minutes. After the constant temperature is over, take out the sample and place it in the air to cool naturally. The sample is inlaid, polished, and placed under an optical microscope for mineral phase detection and analysis. The proportion of calcium ferrite, magnetite, hematite, dicalcium silicate, glass phase and pores is counted. The experimental calculation data of each group are shown in the table below.

[0021]

[0022] As can be seen from Example 1, there is an obvious trend in the proportion of magnetite, hematite and calcium ferrite with the change of the alkalinity of the mixture. As the alkalinity increases, the amount of calcium ferrite generated increases significantly, while magnetite and hematite decrease relatively, and the content of dicalcium silicate also increases to a certain extent. From the above phenomenon, it can be seen that the alkalinity has a positive effect on the mineralization properties of the sintered ore mixture. The glass phase is generated in a small amount and does not fluctuate much because the materials are mixed evenly. As for the pores, because the sample is a pressed sample, the proportion is also small and does not fluctuate much. Example 2 (Mg / Al ratio)

[0023] In this embodiment, by adjusting the proportion of various raw and auxiliary materials, stabilizing the basicity and MgO content, and regulating the Al2O3 content, a sintering mixture with four gradients of magnesium-aluminum ratio ranging from 1.5 to 0.6 is obtained.

[0024]

[0025] Add water to the lime to digest and dry again, then put all kinds of raw and auxiliary materials into the drying oven for drying for 2 hours. This is to facilitate the subsequent control of the moisture content of the mixture. Weigh all kinds of raw and auxiliary materials according to the designed ratio. After weighing, the lime needs to be digested with water and dried again, then mixed and the mixture is put into a mortar to mix thoroughly. Add an appropriate amount of deionized water (3~5%) to the mixed mixture to enhance its molding ability. Use a sample press to press the mixture into a round cake with a specification of φ16mm×10mm, and the sample making pressure is 1.2kN / cm 2 , holding time is 20s.

[0026] Heat the muffle furnace to 1230℃, and the atmosphere is air. Place the prepared sample on a platinum pad, and then put it into the muffle furnace and keep it at a constant temperature for 8 minutes. After the constant temperature is over, take out the sample and place it in the air to cool naturally. The sample is inlaid, polished, and placed under an optical microscope for mineral phase detection and analysis. The proportion of calcium ferrite, magnetite, hematite, dicalcium silicate, glass phase and pores is counted. The experimental calculation data of each group are shown in the table below.

[0027]

[0028] As can be seen from Example 2, there is an obvious trend in the proportion of magnetite, hematite and calcium ferrite with the change of the magnesium-aluminum ratio of the mixture. As the basicity increases, the amount of calcium ferrite generated increases significantly, while magnetite and hematite decrease relatively, and the content of dicalcium silicate fluctuates little and is generally low. From the above phenomenon, it can be seen that the appropriate magnesium-aluminum ratio has a positive effect on the mineralization performance of the sintered ore mixture. Moreover, the increase in aluminum content makes better use of the generation of calcium ferrite, while suppressing the generation of dicalcium silicate and glass phase.

[0029] The above description is only a specific embodiment of the present invention, but the structural features of the protection scope of the present invention are not limited thereto. Any changes or modifications made by any technician in the field of the present invention are all covered by the patent scope of the present invention.

Claims

1. A method for analyzing the mineralization performance of sintered mixed materials by pre-sintering and mineral phase detection, characterized in that: The following steps are involved: Step 1: Grind the raw materials and auxiliary materials, the proportion of particles with a fine grinding size of less than 200 mesh is greater than 90%, and put the finely ground raw materials and auxiliary materials into a drying oven for drying; Step 2: Detect the chemical composition of raw and auxiliary materials, including the mass proportion of TFe, SiO2, CaO, MgO, and Al2O3 in iron ore concentrate, sintering return ore, blast furnace return ore, and purchased ore powder, and the mass proportion of SiO2, CaO, MgO, and Al2O3 in lime and dolomite; Step 3: Weigh and mix the raw materials and auxiliary materials according to the designed ratio. After weighing, the lime needs to be digested with water and dried again. The drying temperature is 105℃ and the time is 2h. Put the weighed mixed material into a mortar and mix it thoroughly. Add 3~5% deionized water to the mixed material and use a press to press the mixture into a round cake with a specification of φ16mm×10mm. The sample making pressure is 1.2kN / cm 2 , the final holding time is 20s; Step 4: Heat the muffle furnace to 1230-1250°C, with air as the atmosphere, place the prepared round cake on a platinum pad, put the round cake into the muffle furnace, and keep the temperature constant for 5-10 minutes. After the constant temperature is over, take out the round cake and place it in the air to cool naturally; Step 5: After inlaying and polishing the round cake, place it under an optical microscope for mineral phase detection and analysis, and calculate the proportions of calcium ferrite, magnetite, hematite, glass phase and pores respectively.

2. The method for analyzing the mineralization performance of sintered mixed materials by pre-sintering and mineral phase detection according to claim 1, characterized in that: In step 1, drying is performed in a drying oven at a temperature of 105° C. for 2 h.

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