Method for detecting ferrous iron in sintered ore

Abstract

The invention relates to a method for detecting ferrous iron in sintered ore. The method comprises the following steps: acquiring a sample; grinding, detecting the magnetic induction intensity, and calculating the ferrous content according to the magnetic induction intensity. According to the sinter ferrous iron detection method provided by the invention, modeling is performed on sinter ferrous iron detection with different magnetite addition amounts in the sinter, and automatic matching is performed by using an automatic control system, so that the influence of the mineral effect and sintering process system of the sinter on the accuracy of magnetic induction ferrous iron measurement is reduced.

Description

Technical Field

[0001] The invention relates to a method for detecting ferrous iron in sintered ore, and belongs to the technical field of sintered ore detection. Background Art

[0002] Sintered ore is an important raw material for blast furnace ironmaking in steel plants. The ferrous index of sintered ore is closely related to blast furnace ironmaking. Too low ferrous content affects the strength of sintered ore, while too high content increases the coke ratio and fuel consumption. The sintering process needs to track the ferrous content in time to adjust the process parameters.

[0003] At present, the methods for online detection of ferrous iron in sintered ore mainly include the manual experience method of observing pyrotechnics, electromagnetic induction method, image recognition method, thermodynamic data model and other methods. The errors of these methods are relatively large, and the sintering process cannot make process parameter adjustments based on these detection data. Its main function is to use it as a reference for real-time process production of sintering.

[0004] The ferrous iron detection mode used to adjust the production process is still to take samples from the sintering site and send them to the laboratory for testing. Most steel plant laboratories use manual titration and some steel plants use X-ray fluorescence diffraction detection. These laboratory detection methods all require manual operation. It takes 60 minutes to manually titrate a sample of ferrous iron, and the X-ray fluorescence detection method also requires manual participation in sample preparation. The laboratory needs to be equipped with at least one analyst to complete the ferrous iron detection task of sintered ore. In order to improve the labor efficiency of sintered ore detection in steel plants, it is very necessary to develop a fully automatic unmanned rapid detection and analysis system in the laboratory. Summary of the invention

[0005] The technical problem to be solved by the present invention is: to overcome the shortcomings of the above-mentioned technology, to provide a method for detecting ferrous iron in sintered ore which solves the problem of large error in the existing electromagnetic induction detection of ferrous iron in sintered ore, and to achieve unmanned continuous and automatic detection of ferrous iron in the laboratory through control by an automatic control system, thereby greatly improving labor efficiency and increasing the degree of automation of ferrous iron detection in sintered ore.

[0006] In order to solve the above technical problems, the technical solution proposed by the present invention is: a method for detecting ferrous iron in sintered ore, comprising the following steps: (1) Obtain samples; weigh and quantitatively divide the samples to be tested; (2) Add a certain amount of binder to the sample and grind it; after grinding, weigh it again; (3) Detect the magnetic induction intensity of the sample after grinding; (4) Calculate the ferrous content based on the magnetic induction intensity.

[0007] The above scheme is further improved in that: the calculation process of step (4) is as follows: Match the sintered ore magnetic induction ferrous iron calculation model according to the sample number, sintering unit, and addition amount of magnetite. The sintered ore magnetic induction ferrous iron calculation model is divided into two steps. In the first step, establish a linear equation between the magnetic induction intensity of sintered ore without magnetite addition and the ferrous iron content of sintered ore. In the second step, establish a model for the contribution value k of the addition amount of magnetite in sintered ore to the linear equation between the magnetic induction intensity of sintered ore and the ferrous iron content in the first step. The model of k is obtained by fitting the difference between the chemical detection value of ferrous iron in sintered ore under different addition amounts of magnetite and the calculated value of the magnetic induction linear equation of sintered ore without magnetite addition and the addition amount of magnetite. The calculation formula of the sintered ore magnetic induction ferrous iron calculation model is: ; where Y is the ferrous iron content of sintered ore; X is the addition amount of magnetite in sintered ore. When the addition amount of magnetite X = 0 in sintered ore, there is a linear equation relationship between the ferrous iron content of sintered ore and the magnetic induction intensity of sintered ore, where a and b are dimensionless coefficients of the linear equation; when the addition amount of magnetite in sintered ore , is the contribution value of the addition of magnetite in sintered ore to the magnetic induction ferrous iron measurement, ; where e is the natural constant, and the contribution value and the addition amount of magnetite X in sintered ore are in a power function relationship, and c, d, and m are dimensionless coefficients of the power function; substitute the magnetic induction intensity of the sample into the of the formula, , ; calculate the ferrous iron content of sintered ore.

[0008] A further improvement of the above solution is that in the step (1), the sample is quantitatively reduced to 30 g per portion. After separating two portions, the remaining sample is packed as the third portion.

[0009] A further improvement of the above solution is that in the step (2), the sample is ground to a sieve passing rate of 90% at 200 mesh.

[0010] A further improvement of the above solution is that in the step (2), the amount of binder added is the same as the amount of sample.

[0011] A further improvement of the above solution is that in the step (3), the magnetic induction intensity of the sample is the measured magnetic induction intensity minus the magnetic induction intensity

[0012] A further improvement of the above solution is as follows: when the automatic detection and control system for ferrous iron in sinter receives a sample detection instruction entrusted by the superior system, it sends the entrusted instruction from the superior to point A of pneumatic sample delivery at the sintering site. The sample delivery personnel load the corresponding sample into the pneumatic shell according to the pneumatic delivery instruction and transmit it through pneumatic delivery to point A of the wind tunnel sample collection at the automatic detection location. The robot at point A of the wind tunnel sample collection grabs the pneumatic shell and takes out the sample, then conducts weighing and quantitative reduction; then, the robot sends the quantitatively reduced sample to grinding; after grinding is completed, the sample is collected by the robot and sent into the magnetic induction intensity instrument.

[0013] The method for detecting ferrous iron in sinter provided by the present invention ensures the fineness of the sample, the sample is not sieved, no sample is discarded, and the measured ferrous iron content can represent the ferrous iron content of the sample itself. The sinter ore sample amount is accurately weighed to ensure the sample amount and density during magnetic induction intensity detection are fixed, and the magnetic induction blank value of the glass test tube is deducted, improving the accuracy of ferrous iron content detection in sinter ore samples. The sample is ground with a quantitative binder, diluting the sinter ore sample, reducing the mineral effect of the sinter ore, and improving the accuracy of ferrous iron detection in sinter ore. Modeling is carried out on the detection of ferrous iron in sinter ore with different magnetite addition amounts and automatically matched using an automated control system to reduce the mineral effect of sinter ore and the influence of the sintering process system on the accuracy of magnetic induction for ferrous iron detection. Using robots and an automated control system to achieve continuous 24-hour unattended detection of ferrous iron in sinter ore improves the labor efficiency of the steel plant and enhances the automation and intelligence of ferrous iron detection in sinter ore. Embodiment

[0014] Example: The method for detecting ferrous iron in sinter ore of this example includes the following steps: (1) Obtain the sample; weigh and quantitatively reduce the sample to be detected; (2) Add a quantitative binder to the quantitatively good sample for grinding; after grinding is completed, weigh again; (3) Detect the magnetic induction intensity of the sample after grinding is completed; (4) Calculate the ferrous iron content based on the magnetic induction intensity; the calculation process is as follows, Match the calculation model for magnetic induction to detect ferrous iron in sinter ore according to the sample number, sintering unit, and magnetite addition amount; The calculation model for magnetic induction to detect ferrous iron in sinter ore is divided into two steps. The first step is to establish a linear equation between the magnetic induction intensity of sinter ore without magnetite addition and the ferrous iron content of sinter ore. The second step is to establish a model for the contribution value k of the magnetite addition amount in sinter ore to the linear equation between the magnetic induction intensity and the ferrous iron content in the first step. The model of k is obtained by fitting the difference between the chemical detection value of ferrous iron in sinter ore under different magnetite addition amounts and the calculated value of the magnetic induction linear equation of sinter ore without magnetite addition and the magnetite addition amount.

[0015] The calculation formula of the magnetic induction ferrous iron calculation model for sinter is as follows: ; where Y is the ferrous iron content of the sinter, X is the addition amount of magnetite in the sinter. When the addition amount of magnetite X = 0 in the sinter, the ferrous iron content of the sinter and the magnetic induction intensity of the sinter show a linear equation relationship, where a and b are dimensionless coefficients of the linear equation; when the addition amount of magnetite in the sinter , is the contribution value of the addition of magnetite in the sinter to the magnetic induction ferrous iron measurement, ; where e is the natural constant, and the contribution value and the addition amount X of magnetite in the sinter are in a power function relationship, and c, d, and m are dimensionless coefficients of the power function; substituting the magnetic induction intensity of the sample into the of the formula, , ; the ferrous iron content of the sinter is calculated.

[0016] The k value here only considers the influence of one kind of magnetite (whose ferrous iron value is 20 itself) on the ferrous iron detection model.

[0017] The ferrous iron detection method for sinter in this embodiment is implemented based on an automatic ferrous iron detection system. The automatic ferrous iron detection system includes pneumatic sample delivery points A and B at the sinter production site, pneumatic sample receiving points A and B in the laboratory, an oven, a quantitative sample divider, a packing and labeling machine, a sample grinder, sample weighing equipment, a ferrous iron detector, and a computer control system.

[0018] When the automatic ferrous iron detection control system for sinter receives a sample detection instruction entrusted by the superior system (sample number, sintering unit, addition amount of magnetite, ferrous iron value of magnetite), it sends the entrusted instruction by the superior to pneumatic sample delivery point A at the sinter site. The sample delivery personnel load the corresponding sample into a pneumatic shell according to the pneumatic delivery instruction and transmit it through pneumatic conveyance to pneumatic sample receiving point A at the automatic detection location. After the sample arrives, the control system analyzes the sample information received at pneumatic sample receiving point A. The sample delivery personnel need to measure a full cup of sinter sample with a measuring cup.

[0019] The robot grabs the shell, takes out the sample, and uses a balance to weigh the total amount of the incoming sample for confirmation. It is confirmed that the total amount is between 90 g and 120 g. Otherwise, the control system alarms and no further steps are taken.

[0020] The robot pours the sinter sample in the shell into the quantitative sample divider. In the quantitative sample divider, a vibrating feeder is used for vibrating feeding and a percentile electronic balance is used for weighing to quantitatively divide the sample into 3 samples. First, two samples of 30.00 g are divided, and the last one packs the remaining sample.

[0021] The robot will separately send the three divided samples to the packing machine for packing and coding, the sample grinding machine for sample grinding, and the buffer position for duplicate sampling.

[0022] After the sintered ore sample is put into the grinding disc of the grinding machine, 15 pellets of binder are automatically added through the track feeding. Each pellet of binder is 0.2 g, and the amount of binder is controlled by an infrared counter. The speed during track feeding should not be too fast, and the vibration speed is 8300. If it is too fast, it is possible that the infrared counter miscounts the number of binder pellets, resulting in inconsistent dilution of the sample.

[0023] After the sintered ore sample and the binder are both put into the grinding disc of the grinding machine, automatic grinding starts. The grinding speed is 1200, the grinding time is 2 minutes, and the sieving rate of the sample is guaranteed to be 90% passing through a 200-mesh sieve. The ground sample is automatically collected in a sample cup.

[0024] Weigh 6.0000 g of the diluted and ground sintered ore using an analytical balance with a precision of one ten-thousandth.

[0025] The robot grabs an empty glass tube and inserts it into the magnetic induction intensity instrument to detect the magnetic induction intensity of the empty test tube. .

[0026] The robot grabs the sample cup containing 6 g of the sample and pours it into the glass test tube. At the same time, a vibrator is used to vibrate the glass test tube at a fixed frequency to compact the powder sample; the compacted glass tube is inserted into the magnetic induction intensity instrument to detect the magnetic induction intensity. ; Thus, the magnetic induction intensity of the sample is obtained. .

[0027] The ferrous iron automatic detection system automatically matches the magnetic induction ferrous iron calculation model of the sintered ore according to the sample information (sample number, sintering unit, addition amount of magnetite) entrusted by the superior system.

[0028] After the calculation result of the ferrous iron content of the sintered ore comes out, it is uploaded to the superior system. The superior system calculates and judges whether a duplicate sample is needed. The superior system compares the detected data of the ferrous iron content of this sintered ore sample with the ferrous iron content of the previous sintered ore on the same sintering unit. If it exceeds the set value, a retest is carried out. During the retest, the robot takes the buffer sample cup from the buffer rack and repeats the test once. If the difference between the two test results is within the tolerance range, the last test result is reported. If it exceeds the tolerance, the automated system alarms to remind, and the personnel use the control sample to check the equipment status.

[0029] All the above procedures are controlled by a computer program and operated remotely, which greatly improves the labor efficiency.

[0030] Take the ferrous iron detection model of the sintered ore of No. 4 sintering machine as an example.

[0031] For the No. 4 sintering machine, considering the influence of the magnetite dosage on the ferrous iron measurement of the magnetic induction intensity of the sinter, the contribution of the magnetite dosage to the ferrous iron measurement of the magnetic induction of the sinter sample was fitted, and a magnetic induction ferrous iron measurement model including the contribution of the magnetite dosage was established. The automated system was connected to the superior system to receive the information of the sinter sample. After the magnetic induction intensity of each sinter sample was detected, the automated system automatically matched the calculation model and calculated the ferrous iron content of the sinter sample and then uploaded it back to the superior system. ; .

[0032]

[0033] The differences between the values obtained in this embodiment and the detection values of the national standard GBT 6730.8-2016 "Iron ores - Determination of ferrous iron content - Potassium dichromate titrimetric method" are all within the range of 0.6, which proves that the method has high accuracy.

[0034] Verify the repeatability of this embodiment again.

[0035] Select a 1500 g sample of the No. 5 sintering machine with a magnetite addition of 13.98% and a ferrous iron value of 21.62% for the magnetite. The automated control system assigned the detection task to repeat the detection 12 times. The standard deviation of the 12 repeated tests meets the requirements of the national standard GBT 6730.8-2016 "Iron ores - Determination of ferrous iron content - Potassium dichromate titrimetric method". Serial number Ferrous value of the 5 sintering units 1 10.49 2 10.48 3 10.67 4 10.65 5 10.49 6 10.42 7 10.69 8 10.71 9 10.72 10 10.54 11 10.57 12 10.62 Average value 10.59 Maximum value 10.72 Minimum value 10.42 Standard deviation 0.10 2.77 times the standard deviation 0.28 Tolerance 0.3 By the method of this embodiment, a large sinter sample was measured 12 times repeatedly. The standard deviation of the 12 repeated tests meets the requirements of the national standard GBT 6730.8-2016 "Iron ores - Determination of ferrous iron content - Potassium dichromate titrimetric method", which proves that the method is reliable.

[0036] The present invention is not limited to the above embodiments. All technical solutions formed by equivalent replacement fall within the protection scope required by the present invention.

Claims

1. A method for detecting ferrous iron in sinter, characterized in that, It includes the following steps: (1) Obtain the sample; weigh and quantitatively reduce the sample to be tested. (2) Add a quantified binder to the quantified sample and grind it. After grinding is completed, weigh again. (3) Detect the magnetic induction intensity of the sample after grinding is completed. (4) Calculate the ferrous iron content based on the magnetic induction intensity.

2. The sinter ferrous detection method according to claim 1, characterized in that: The calculation process in step (4) is as follows. Match the sinter ore magnetic induction ferrous iron calculation model according to the sample number, sintering unit, and the addition amount of magnetite. The sinter ore magnetic induction ferrous iron calculation model is divided into two steps. First, establish a linear equation between the magnetic induction intensity of the sinter ore without magnetite addition and the ferrous iron content of the sinter ore. Second, establish a model for the contribution value k of the addition amount of magnetite in the sinter ore to the linear equation between the magnetic induction intensity of the sinter ore and the ferrous iron content in the first step. The model of k is obtained by fitting the difference between the chemical detection value of ferrous iron in the sinter ore under different addition amounts of magnetite and the calculated value of the magnetic induction linear equation of the sinter ore without magnetite addition and the addition amount of magnetite. The calculation formula of the magnetic induction ferrous iron calculation model for sinter is as follows: ; where Y is the ferrous iron content of the sinter; X is the addition amount of magnetite in the sinter. When the addition amount of magnetite in the sinter X = 0, the ferrous iron content of the sinter and the magnetic induction intensity of the sinter show a linear equation relationship, where a and b are dimensionless coefficients of the linear equation; when the addition amount of magnetite in the sinter , is the contribution value of the addition of magnetite in the sinter to the magnetic induction ferrous iron measurement, ; where e is the natural constant, and the contribution value and the addition amount of magnetite X in the sinter are in a power function relationship, and c, d, m are dimensionless coefficients of the power function; substitute the magnetic induction intensity of the sample into the of the formula, , ; calculate the ferrous iron content of the sinter.

3. The sinter ferrous detection method according to claim 1, characterized in that: In step (1), the sample is quantitatively reduced to 30 g per portion. After two portions are separated, the remaining sample is packed as the third portion.

4. The sinter ferrous iron detection method according to claim 1, characterized in that: In step (2), the sample is ground to a sieve passing rate of 90% at 200 mesh.

5. The sinter ferrous iron detection method according to claim 1, characterized in that: In step (2), the amount of binder added is the same as the amount of the sample.

6. The sinter ferrous detection method according to claim 1, characterized in that: In the said step (3), the magnetic induction intensity of the sample is the measured magnetic induction intensity minus the magnetic induction intensity of the container holding the sample .

7. The sinter ferrous iron detection method according to claim 1, characterized in that: When the sinter ore ferrous iron automatic detection control system receives a sample detection instruction entrusted by the superior system, it sends the entrusted instruction by the superior to the pneumatic sample delivery point A at the sintering site. The sample delivery personnel load the corresponding sample into the pneumatic shell according to the pneumatic delivery instruction and transmit it through the pneumatic system to the wind tunnel sample receiving point A at the automatic detection location; the robot at the wind tunnel sample receiving point A grabs the pneumatic shell and takes out the sample, then weighs and quantitatively reduces it; then, the robot sends the quantitatively reduced sample to be ground. The sample after grinding is collected by the robot and sent into the magnetic induction intensity instrument.

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