Method for measuring reduction performance of iron ore under simulated blast furnace reduction condition

Abstract

The invention discloses a method for measuring reduction performance of iron ore under simulated blast furnace reduction conditions, and belongs to the technical field of metallurgy. According to the method, under the simulated blast furnace reduction condition, according to the temperature change of the iron ore in a blast furnace blocky zone, the reduction condition of a system where the iron ore is located is more consistent with the actual situation of blast furnace production by changing the parameters such as the reduction temperature, the temperature rising speed and the reduction time of the iron ore, and the measured data is more close to the actual production of the blast furnace. The method is easy and convenient to operate, different iron ores for the blast furnace can be detected, the obtained data can better evaluate the reduction performance of the iron ores, the method is closer to blast furnace production, a certain guiding effect is achieved on blast furnace production operation, and the method has good application and popularization value.

Description

Technical Field

[0001] This invention belongs to the field of metallurgical technology, and in particular relates to a method for determining the reduction performance of iron ore under simulated blast furnace reduction conditions. Background Technology

[0002] The reducibility of iron ore refers to the ease with which a reducing gas (CO) can remove oxygen bound to iron from the ore under the temperature conditions of blast furnace smelting. It is the most important indicator for evaluating ore quality. In large blast furnace smelting processes, the reduction time of iron ore in the lumpy zone is about 3 hours, and the temperature is generally solid-state reduction at 500-1100℃.

[0003] Currently, the laboratory method for determining the reducibility of iron ore adopts the national standard GB / T 24189-2009 / ISO 7215:2015, "Determination of reducibility of iron ore for blast furnace, expressed as final reducibility index". This method involves passing a reducing gas at a rate of 15 liters per minute through the test sample at a constant temperature of 900℃ for 3 hours, measuring the amount of oxygen lost, and calculating the reducibility of the sample. While the data obtained using this existing method can provide a quality assessment of the selected ore, it is difficult to reflect the actual production status of the iron ore within the blast furnace.

[0004] Application No. 202211273311.6, "A method for determining the reducibility of iron ore", involves continuously heating the temperature at a certain rate from 500℃ to 1000℃, changing the concentration of reducing gas every hour. The measured reducibility data can provide some guidance for blast furnace production. However, the method uses three types of reducing gases, making the actual operation complex. Summary of the Invention

[0005] The purpose of this invention is to provide a method for measuring the reduction performance of iron ore under simulated blast furnace reduction conditions. This method simulates the reduction conditions of iron ore under blast furnace reduction conditions and, based on the temperature change of iron ore in the blast furnace blocky zone, changes parameters such as the reduction temperature, heating rate, and reduction time of the iron ore to make the reduction conditions of the iron ore system more consistent with the actual situation of blast furnace production, and the measured data is closer to the actual production of the blast furnace.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0007] This invention discloses a method for determining the reduction performance of iron ore under simulated blast furnace reduction conditions, comprising the following steps:

[0008] 1) Dry the iron ore sample in an oven at 105℃±5℃;

[0009] 2) Weigh a 10-12.5 mm iron ore sample and place it into the reaction tube of the reduction furnace;

[0010] 3) Place the reaction tube containing the sintered ore sample into the reduction furnace and turn on the power to raise the temperature;

[0011] 4) The temperature of the blocky zone inside the blast furnace was simulated by heating in four stages: the first stage was 0℃ to 500℃ at a heating rate of 10℃ / min; the second stage was 500℃ for 30 minutes at a heating rate of 0℃ / min; the third stage was 500℃ to 900℃ at a heating rate of 5℃ / min; and the fourth stage was 900℃ to 1100℃ at a heating rate of 2℃ / min.

[0012] 5) During the process of passing reducing gas, the degree of reduction of iron ore is calculated in real time based on the amount of oxygen lost from the sample and the known contents of TFe and FeO in the iron ore.

[0013] 6) After the reduction time is over, stop the reducing gas and cool with N25L / min.

[0014] Furthermore, the first stage uses N25L / min.

[0015] Furthermore, the N2 flow rate for the second stage is 15 L / min.

[0016] Furthermore, in the third and fourth stages, a reducing gas flow rate of 15 L / min is introduced, and the reduction time is 180 minutes.

[0017] Furthermore, the composition of the reducing gas by mass percentage includes: CO + N2 = 30% + 70%.

[0018] Furthermore, in step 1), the iron ore sample is dried in an oven at 105°C for 2 hours.

[0019] Furthermore, in step 2), 500g of an iron ore sample with a diameter of 10-12.5mm is weighed.

[0020] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0021] The method of this invention is simple and convenient to operate, and can be used to test different iron ores for blast furnaces. The data obtained can better evaluate the reduction performance of iron ore, which is closer to blast furnace production. It has a certain guiding role in blast furnace production operation and has good promotion and application value.

[0022] Instruction manual illustrations

[0023] Figure 1 This is a flowchart of a method for determining the reduction performance of iron ore under simulated blast furnace reduction conditions according to the present invention. Detailed Implementation

[0024] A method for determining the reduction performance of iron ore under simulated blast furnace reduction conditions includes:

[0025] 1) Weigh 500 grams of sintered ore sample with a diameter of 10-12.5 mm and place it into the reaction tube of the reduction furnace;

[0026] 2) Place the reaction tube containing the sintered ore sample into the reduction furnace and turn on the power to raise the temperature;

[0027] 3) The temperature rise simulates the temperature conditions of the blocky zone inside the blast furnace. The heating rate is 10℃ / min from 0℃ to 500℃, 5℃ / min from 500℃ to 900℃, and 2℃ / min from 900℃ to 1100℃.

[0028] 4) Before reaching 500℃, the flow rate of N2 is 5L / min. When the temperature approaches 500℃, the temperature is kept constant for 30 minutes, and the flow rate of N2 is changed to 15L / min.

[0029] 5) After the constant temperature of 500℃ is completed, switch to reducing gas (CO+N2=30%+70%) at 15L / min, and the reduction time is 180 minutes;

[0030] 6) Based on the oxygen loss of the sample, the reducing power of the iron ore is calculated in real time using the known TFe and FeO contents of the iron ore;

[0031] 7) After the reduction time is over, stop the reduction gas and cool with N25L / min.

[0032] Table 1 Comparison results of the method of the present invention with the national standard GB / T 24189-2024

[0033]

[0034] Table 2 Results of reduction tests on sintered ore under simulated blast furnace blocky zone temperature conditions

[0035] Temperature / °C 500 600 700 800 900 1000 1100 Reduction degree / % 6.5 9.0 18.2 35.4 52.8 67.7 86.8

[0036] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for determining the reduction performance of iron ore under simulated blast furnace reduction conditions, characterized in that, Includes the following steps: 1) Dry the iron ore sample in an oven at 105℃±5℃; 2) Weigh a 10-12.5 mm iron ore sample and place it into the reaction tube of the reduction furnace; 3) Place the reaction tube containing the sintered ore sample into the reduction furnace and turn on the power to raise the temperature; 4) The temperature of the blocky zone inside the blast furnace was simulated by heating in four stages: the first stage was 0℃ to 500℃ at a heating rate of 10℃ / min; the second stage was 500℃ for 30 minutes at a heating rate of 0℃ / min; the third stage was 500℃ to 900℃ at a heating rate of 5℃ / min; and the fourth stage was 900℃ to 1100℃ at a heating rate of 2℃ / min. 5) During the process of passing reducing gas, the degree of reduction of iron ore is calculated in real time based on the amount of oxygen lost from the sample and the known contents of TFe and FeO in the iron ore. 6) After the reduction time is over, stop the reducing gas and cool with N25L / min.

2. The method for determining the reduction performance of iron ore under simulated blast furnace reduction conditions according to claim 1, characterized in that, The first stage uses N25L / min.

3. The method for determining the reduction performance of iron ore under simulated blast furnace reduction conditions according to claim 1, characterized in that, The flow rate of N2 in the second stage is 15 L / min.

4. The method for determining the reduction performance of iron ore under simulated blast furnace reduction conditions according to claim 1, characterized in that, In the third and fourth stages, the reducing gas is passed at a rate of 15 L / min, and the reduction time is 180 minutes.

5. The method for determining the reduction performance of iron ore under simulated blast furnace reduction conditions according to claim 4, characterized in that, The reducing gas composition by mass percentage includes: CO + N2 = 30% + 70%.

6. The method for determining the reduction performance of iron ore under simulated blast furnace reduction conditions according to claim 1, characterized in that, In step 1), the iron ore sample is dried in an oven at 105°C for 2 hours.

7. The method for determining the reduction performance of iron ore under simulated blast furnace reduction conditions according to claim 1, characterized in that, In step 2), 500g of iron ore sample with a diameter of 10-12.5mm is weighed.

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