JPH0354780B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) This invention relates to the charging density, porosity, and distribution of sintered compound raw materials in a layered state charged to a sintered pallet of an iron ore sintering machine, ore, coke, and Online analysis of coarse particle distribution by type of raw material using X-rays or γ
It relates to a method of measuring using radiation such as rays and neutrons. (Prior art) Sintered iron ore is produced by charging a mixture of powdered iron ore, component regulators such as limestone, silica, and serpentine, and coke as an auxiliary material onto a sintered bed and sintering it. However, since sintered ore is manufactured by a reaction that does not completely melt, but partially generates and combines the molten ore, the charging condition of the mixed raw materials onto the sintering bed (charging density, The porosity (porosity and its distribution) and the distribution of coarse particles that form the framework of the filling structure are important characteristic factors that control the air permeability of the sintered bed, the sintering reaction, and ultimately the structure of the sintered ore that is the final product. It is. Conventionally, there is no way to directly measure the charging condition, so attempts have been made to process the sample and then bury it in resin and observe the polished surface under a microscope, but it takes about 70 hours to obtain results from the sample. Because of the requirements, it has only been carried out within the scope of laboratory research. Industrially, there is a method of estimating the average ventilation resistance of the entire bed from the pressure drop of the bed, or
As proposed in Publication No. 171532, a method is used to estimate the amount by model calculation according to the raw material composition based on the raw material characteristics of each brand. All of these methods are only methods for estimating the charging state of the entire bed on an average and indirectly, and cannot grasp the actual situation. In addition, if we try to directly measure the coarse particle distribution that determines the charging condition, it is necessary to
The only way to do this is to use the sampler disclosed in the publication, stop the sintering machine, sample at each position, and then pass it through a sieve to measure it. This method also does not measure the actual situation as it is, and requires a great deal of time and effort, so it is only implemented in special cases such as experiments in research and development. There is a large difference in the actual charging state of mixed raw materials in the height and width directions, and controlling this is the most desirable operating method in actual operation, but currently it is difficult to directly measure the charging state. Since there is no way to do this, the current situation is to try and find the optimum charging conditions, such as the sloping chute angle, through trial and error while looking at operational results. but,
This method is based on intuition, and there is no guarantee that the optimal solution will be found.Furthermore, it takes a huge amount of time to find the right conditions, and during that time it is necessary to perform potentially wasteful operations. (Problems to be Solved by the Invention) The purpose of the present invention is to solve the above-mentioned problems, to sample the blended raw materials on the sintered bed as they are, and to sample the mixed raw materials on the sintered bed in one or more longitudinal cross-sectional directions. Or similarly, measurement is performed by irradiating radiation such as X-rays, gamma rays, or neutrons in one or more cross-sectional directions or both, and the signals forming each cross-sectional image are analyzed and processed. By controlling the raw material mixture and raw material charging method so that the charging density, porosity, and coarse particle distribution state reach the target state, the appropriate state can be formed accurately and quickly, and wasteful sintered ore production can be avoided. The aim is to eliminate this, improve and stabilize the quality of sintered ore, reduce various basic units, and improve product yield. (Means and effects for solving the problems) The present invention solves all the problems mentioned above, and further improves the quality, yield, and various basic units of sintered ore, as follows. It is configured. In other words, the gist of the present invention is to insert a cylindrical sampler in the layer thickness direction from the surface of the sintered compound raw material charged onto the sintered pallet at a desired location to sample the raw material (hereinafter referred to as a core sample). A tomographic image of a cross section or a longitudinal section of the collected raw material is taken with a radiation irradiation imager, and from this taken tomographic image, it is possible to determine the charging density, porosity, and This is a method of measuring coarse particle distribution. Since the present invention is configured as described above, it is possible to quickly check the charging state of the mixed raw materials immediately before the sintering reaction, the charging density, porosity, and distribution of coarse particles for each type of raw material at each predetermined position. Because it can be accurately grasped, it is possible to quickly and accurately achieve a clear goal, compared to conventional deductive methods that took a lot of time and effort, and methods that searched for the optimal state through trial and error. can be done. (Example) Fig. 1 shows the core sampler used in this example, and Fig. 2 A, B, and C show cross-sectional images of the core sampler obtained in this example. The core sampler shown in FIG. 1 is constructed as follows. When the sintering raw material 1 is cut out from the drum feeder 2 and supplied to the pallet 3 via the slopping chute 5, the drum feeder 2
A sampling device 6 is disposed at an appropriate position between the sampling rod 7 and the ignition furnace 4, and the sampling rod 7 is driven by an elevating device 8 to serve as a cylindrical sampler that is removably attached to the lower end of the sampling rod 7. The core sample is collected by inserting the collection chamber 71 into the raw material layer until it reaches a predetermined depth. In addition, 9 is a turning device, and 1
0 is a device that guides the raising and lowering of the collection chamber 71. Then, the lifting device 8 is reversed and pulled up to remove the collection chamber 71 from the collection rod 7. In this way, the length of the sample was 60 cm and the diameter was 15 cm.
X on a cylindrical (or prismatic) core sample.
A radiation imaging device irradiates X-rays from around the core sample. At this time, the core sample is transported so as not to give an impact, and the core sample is measured as it is (stored in the collection chamber 71). Alternatively, when the core sample in the collection chamber 71 is impregnated with resin and solidified, and then the solidified core sample is taken out from the collection chamber 71 and measured, the core sample is on the sintered pallet at the time of measurement. Care should be taken to ensure that this does not change. As mentioned above, X-rays are irradiated from multiple points in the circumferential direction of the side surface of the core sample, and the transmitted X-rays at each point are measured.
By performing image processing based on the dose, the CT value (this is the ratio of the absorption coefficient of the sample to the absorption coefficient of water related to X-rays, and this ratio varies depending on the material of the sample) is obtained from the core samples shown in Figure 2 A to C. Obtain each cross-sectional image at each position in the height direction. In addition, Fig. 2 A is a 60 cm long core sample 15 cm from the top surface (the surface of the sintered raw material on the sintering bed), and the second
Figure (b) shows a tomographic image at a position 30 cm from the upper surface of the core sample, and Figure 2 (c) shows a tomographic image at a position 45 cm from the upper surface of the core sample. Each cross-sectional image is processed to measure the charging density, porosity, and coarse particle distribution in the layer thickness direction of the sintering raw material charged onto the sintered bed. (A) In other words, the above-mentioned charge density is CT
It utilizes the fact that the value is proportional to the substance, that is, the density of the substance, and the measurement procedure is as follows. From the above CT value for each of the many pixels forming one cross-sectional tomographic image (usually one tomographic image is composed of 512 pixels),
The density ρi is obtained from the following equation (1). ρi=K ₁・CT+K ₂ ...(1) However, K ₁ , K ₂ : Constant, CT: CT value Next, the average density ρa in one tomographic image
is calculated using the following formula (2). ρa= _n 〓 ⁱ⁼¹ ρi/n (2) where n is the number of pixels in one tomographic image (B) Next, the porosity will be explained. As mentioned above, the CT value of this porosity differs depending on the material of the sample (the CT value of air is 25 or less, the CT value of other sintering raw materials, coke, is about 1.2 times that of air, and that of limestone is 1.8
(approximately 3 times as much for iron ore) as follows. Count the number of pixels K, which is the CT value (25 or less) corresponding to air in one tomographic image, and use the following formula (3)
Find the porosity Pa in the tomographic image. Pa=K/n...(3) (C) Furthermore, particle size distribution measurement will be explained below. First, each particle image in the tomographic image shown in FIG. 2 is reduced in size while maintaining a similar shape until each particle image is separated into individual particles. The area Sa of each reduced powder particle image is calculated by counting the number of pixels in the powder particle image. Based on the calculated area Sa of the powder particle image, the original (before reduction) area Sb of each powder particle is calculated using the following formula (4). Sb=Sa/A...(4) where A is the reduction ratio.Regarding this area as the area of a circle, calculate the particle size of each powder particle, and calculate the amount for each particle size. Based on this, particle size of 1 mm or more, 3 mm or more, 5
Find the particle size distribution in mm or more. In this way, the charging density ρb, porosity Pb, and particle size distribution measured from the tomographic images in Figure 2 A to C were processed using the conventional method, together with the results (A) to Table 1.
Shown in (c). The charging density ρb, porosity Pb, and particle size distribution explained above were obtained from the tomographic image of the cross section of the core sample, but they can also be obtained from the tomographic image of the longitudinal section of the core sample instead. That is, a tomographic image of a longitudinal section of the core sample is obtained using an X-ray irradiation imager in the same manner as described above. Next, the number of pixels in the height direction of this tomographic image is divided into a plurality of blocks, and the charging density, porosity, and particle size distribution in the tomographic image located within each block are measured in the same manner as described above.

[Table] As is clear from Table 1, the method of the present invention yielded results that were not substantially different from the conventional measurement methods specified by JIS. This means that it is now possible to grasp the actual state of the sintering raw material before sintering online, and based on this, the charging of the sintering raw material into the pallet in the process can be adjusted, and the predetermined layer position can be adjusted. The charging density, porosity, and coarse particle distribution can be adjusted depending on the material. (Effect of the invention) Conventionally, the charging state of the sintering compound raw material, which is a basic technical index of sintering, was unknown and operations were performed by indirectly and partially estimating it, but by implementing the present invention, Measurements can be accurately and quickly taken online, so
The measured value is the actual situation, the reality itself, and not only does it eliminate the huge amount of time and effort that was required in the past, but it also eliminates wasted operational zones where it was impossible to operate based on accurate measured values. The effects brought about are extremely large, such as making it possible to significantly improve the quality, basic unit, yield, etc. of sintered ore.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an example of a core sampler used in the implementation of the present invention, and FIG. 1...Sintering raw material, 2...Drum feeder, 3
...Pallet, 4...Ignition furnace, 5...Slopping chute, 6...Sampling device, 7...Sampling rod, 71...Sampling chamber, 8...Elevating device, 9
...Turning device, 10...Guiding device.

Claims (1)

[Claims] 1. A cylindrical sampler is inserted in the layer thickness direction from the surface of the sintered mixed raw material charged on the sintered pallet at a desired location to collect the raw material, and a tomographic image of the cross section or longitudinal section of the sampled raw material is radiographed. An image is taken with an irradiation imager, and from the taken tomographic image, the charging density in the layer thickness direction of the sintered compound raw materials on the sintered pallet,
Method for measuring porosity and coarse particle distribution.