JPS63101738A - Production yield measurement for sintered body - Google Patents

Abstract

PURPOSE:To achieve a higher production yield of a sintered body quickly and accurately, by synthesizing an image divided in terms of CT value level per composing pixel from an image of a transverse section taken with a CT scanner to measure the production yield from the area and peripheral length of the image. CONSTITUTION:A sinter-cake-shaped mass of a sintered body is sampled to be irradiated with X-rays and taken with a CT scanner to obtain an image of any transverse section of the sintered body. Images with the CT value above and below 2,000 respectively at 420kV of tube voltage are synthesized per image composing pixel to determine sintering degree eta1={1-M/(M+N)}X100% and breaking yield eta2=(1-kXL/N)X100% from the areas M and N(mm<2>), peripheral length L(mm) and breaking coefficient k(mm). Production yield eta3=eta1Xeta2 is measured from the sintering degree eta1 and breaking yield eta2.

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention provides a sintered body of a product obtained by firing and agglomerating powder and granules;
That is, iron ore sinter and Cr, M n.

The present invention relates to a method for measuring the production yield in the production process of sintered ore for alloys such as Ti.

(Prior art) In a sintering reaction in which a powder or granular material is heated to partially generate a melt, and particles coalesce or bond together using this melt as a medium, insufficient sintering occurs in the generated sintered body. It is easy to form parts. Conventionally, the quality of sintering has been measured by the ratio of the weight of the final product to the weight of the sinter cake at the time of completion of sintering, that is, the product yield. However, measurement of product yield is usually only carried out once every few hours.
Controlling product yield through quick action is difficult.

In addition, this measurement method is affected by many factors other than sintering, such as the quality of the raw materials and the finished product, so when an abnormality occurs in the manufacturing process or the quality of the finished product changes, it is difficult to trace the cause. Actions had to rely on experience and intuition.

As a countermeasure to this problem, Japanese Patent Application Laid-Open No. 110726/1983
A method for directly measuring the degree of sintering using a CT scanner is disclosed. This method uses a 6-blade scanner to image an arbitrary cross section of a sintered body, and the resulting image is divided into sintered areas and unfinished areas based on the CT value, and the percentage of sintered areas is determined. This method directly measures the degree of sintering. According to this method, it is possible to evaluate the decrease in manufacturing yield caused by incomplete sintering. Here, the production yield refers to the ratio of the weight of the product or the weight of the final product at any point in the subsequent product processing and transportation steps to the weight of the sinter cake at the time when sintering is completed. Therefore, for the ratio of final product weight to sinter cake weight, manufacturing yield is equivalent to finished product yield.

On the other hand, even if the sintered body is composed entirely of fired parts,
Since sintered ore is crushed to a considerable extent by being subjected to impacts during product processing and transportation steps such as crushers and screens after sintering, return ore is generated.

In the actual manufacturing process, the manufacturing yield, which includes everything from the sintering process to the finished product processing process and transportation process, has a large impact on manufacturing costs, so it is important to not only measure the degree of sintering but also to measure the yield at the time of crushing. There is a need for a rapid and accurate method for measuring comprehensive manufacturing yields. However,
The method of No. 1-110726 cannot evaluate the production yield including the generation of return ore based on the above-mentioned crushing. Therefore, a comprehensive manufacturing yield evaluation method including the degree of sintering and crushing yield is desired.

(Problems to be Solved by the Invention) The present invention utilizes a cross-sectional image of the sintered body taken by a CT scanner in the sintered body manufacturing process, thereby increasing the manufacturing yield of the sintered body quickly and with high rust resistance. The purpose is to provide a measurement method.

(Means and effects for solving the problems) The present invention has the following features:
In order to achieve the above purpose, it is configured as follows. In other words, from an arbitrary cross-sectional image of a sintered body obtained by imaging with a CT scanner, images with CT values releveled for each constituent pixel are synthesized, and after determining the area and perimeter of the annotated image, these This is a method for measuring the manufacturing yield of a sintered body, characterized in that the manufacturing yield of the sintered body is measured as a function.

In addition, the present invention combines images obtained by releveling CT values of each constituent pixel from arbitrary cross-sectional images of a sintered body obtained by imaging with a CT scanner, and calculates the area and perimeter of the images. This is a method for measuring the manufacturing yield of a sintered body, which is characterized by measuring the manufacturing yield of a sintered body using the following formula.

773 = rj + X772 /100 However, ηl
: Sintering degree [%] η2 : Crushing yield [96] η3 : Manufacturing yield N : Surface M of CT value relevel image that is substantially equivalent to 2000 or more in CT value when tube voltage is 420 kv [mm” ] M: CT value substantially equivalent to less than 2000 when the tube voltage is 420 kV Surface IIt of the relevel image Perimeter length of CT value relevel image [mm] k: Crushing coefficient [mm] The present invention will be described in detail below.

Imaging using a radiation and VIICT scanner was performed using the method described in JP-A-61-110726, and then
An image with a CT value level substantially equivalent to 2000 or more when the tube voltage is 420 kV is synthesized. The CT value specified in the present invention was calculated using the following formula (1) based on the X-ray intensity when measured with a CT scanner, which is substantially equivalent to when the tube voltage is 420 kV. Show value.

CT value = □×K ・・・・−(1) μ W where μS: Absorption coefficient of radiation of sample μw:
Absorption coefficient K of water radiation: Constant (usually = 1000) Next, in JP-A-61-110726, CT value 2
After dividing the image into 000 or more and less than 000 and finding the composite area of each image, the degree of sintering η in the sintering process can be found using the following equation (2).

Mll: Area of the part showing T value 2000 or more [mm2]
N: Area of the part showing a CT value of less than 2000 [mm21 In the present invention, in addition to the above-mentioned composite area, the area has a CT value of less than 20
Measure the circumference of the part of 00 or more. At this time, CT value 2
The area and perimeter of the portion showing 000 or more can be easily determined using a normal image analysis system. For example, the perimeter is calculated by finding the number of pixels corresponding to the perimeter and multiplying this by the unit length of one pixel.

Next, an index for determining the occurrence of return ore in the product processing process and transportation process using the perimeter length, that is, the crushing yield 2, can be determined by the following equation (3).

Here, L: Perimeter length of the image showing a CT value of 2000 or more [OIl] N: Area of the image showing a T value of 2000 or more [III
II+2] k: Fracture coefficient [llll11] Therefore, the manufacturing yield η3 in the sintered body manufacturing process is (4)
As shown in the formula, it is calculated as the product of the degree of sintering η1 and the crushing yield η2.

η3=η1×η2 /100 [! fil...
...-(4) Since the present invention is configured as described above, the crushing yield and manufacturing yield in the sintered body manufacturing process can be measured for each part inside the sintered body without destroying the cross section to be measured. can be measured.

The operation of the present invention will be explained below. A sinter cake-like lump or a part thereof is sampled from the sintered body to be measured. At this time, in the case of a large sintered body sample, for example, a sinter cake of iron ore sinter,
A core sample is taken from the sintered bed using a core sampler such as that proposed in Publication No. 3639. Next, X-rays are irradiated to take a cross-sectional image of the sintered body. In the case of the X-ray method, it can be carried out according to the method disclosed in JP-A-60-203841. Japanese Patent Publication No. 61-1107
No. 26 further develops this method and makes it possible to judge the quality of the sintering process by classifying fired parts and unfinished parts by CT value.

According to experiments conducted by the present inventors, there are two actual causes of return ore generation. One is due to poor firing in the sintering process, and is detected as an incompletely fired portion. The other reason is that the fired part is crushed during the product processing process and transportation process using a crusher, screen, etc.

The inventors believe that the generation of return ore due to crushing is related to the physical shape of the sintered body, and as a result of proceeding with the analysis, the amount of return ore generated from the sintered body is extremely close to the circumference of the sintered part. We found that there is a correlation. The mechanism by which the occurrence of return ore is determined by the circumference length is thought to be the effect of the unevenness of the surface of the sintered body. That is, if the surface of the sintered body has a highly uneven shape, the convex portions are likely to be chipped, and the concave portions become starting points for cracks and tend to generate a large amount of return ore. The crushing yield is therefore given as a function of the perimeter.

According to the study results of the present inventors, the functional relationship between the crushing yield and the perimeter is optimally expressed by the above equation (3). At this time, the crushing coefficient in equation (3) is determined by the impact force during handling in the product processing process and transportation process, and generally varies depending on the sintered body manufacturing equipment.

Sintering machine A in three different iron ore sinter production facilities,
An example of calculating the fracture coefficient of B and C3 groups is shown below.

L/N in the above formula (3) is determined according to the configuration procedure of the method of the present invention, and at the same time, η2 is calculated using the following formula (5) from the product yield record η and the degree of sintering η1.

From the values of η2 and L/N determined by equation (5), the fracture coefficient k is determined by equation (3). As a result of repeatedly measuring η2 and L/N under different operating conditions and investigating the relationship between the perimeter length (L/N) and return ore generation rate (1--) with respect to the area of the sintered part, the first As shown in Figure 00, the slope is different for each sintering machine, but it was found that each sintering machine has a linear slope. Therefore, the crushing coefficient is set for each sintering machine based on the slope of the straight line shown in FIG.

Table 1 shows k determined in FIG. In addition, the correlation coefficients of (L/N) and (1--)+00 in FIG. 1 are also listed in the same table. The correlation coefficients in Table 1 are very high, and according to the final method, it is possible to measure the product yield with high precision.

Table 1 In addition, although the example of the product yield measurement in iron ore sinter manufacturing is shown above, it is not limited to the product yield shown in the head, but is also applicable to the primary,
If the crushing coefficient k until reaching the secondary and tertiary screens and the sintered ore sizing screen in blast furnace equipment is calculated for each screen, it is possible to calculate the production yield after passing through each screen. can.

In addition, although X-rays were used as radiation in the present invention,
Not limited to X-rays, but gamma rays.

The manufacturing yield of a sintered body can also be measured by irradiating radiation such as neutron beams in the same manner as with X-rays.

(Example) (1) A core sample of the sintered cake was collected in the iron ore sintering machine A shown in FIG. 1 by the method proposed in Japanese Patent Publication No. 13639/1982, and imaged with a CT scanner. Using equations (1) to (4) above, η1. η2°η3 was calculated and compared with the product yield in the actual manufacturing process. The results are shown in Table 2. At this time, η2 is k = 1.0
It was calculated as 5. Sintering degree η1 or crushing yield η2
Each of these alone does not correspond to the actual product yield, but if the manufacturing yield η3 is obtained by combining both, fluctuations in the product yield can be measured in real time.

Table 2 ■In iron ore sintering machine B, the case where the product yield is managed by measuring the product yield obtained every 8 hours (conventional method) and the case where the production yield η3 is measured and managed every 30 minutes (final method) A comparison is shown in Figure 2 (a) with changes in product yield performance. The action at this time is
If an abnormal value was determined in the x-R control chart, this was dealt with by increasing or decreasing the amount of coke breeze. In addition, the fracture coefficient is set to 1.25 and η3
was measured.

FIG. 2(b) shows the change in manufacturing yield η3 determined by the final method. By increasing the number of actions in this way,
Stable operations became possible.

(Effects of the Invention) The present invention provides a method for easily measuring the manufacturing yield of each position within a sintered body from its internal structure without destroying the sintered body. In the actual sintered body manufacturing process, by outputting quick and accurate measurement results as necessary, real-time action can be taken against yield fluctuations.

Therefore, it is extremely effective in improving the yield and reducing costs in the sintered body manufacturing process.

[Brief explanation of the drawing]

Figure 1 shows the perimeter length (L/N) of the completed sintered part and the return ore generation rate (1-
-), FIG. 2(a) is a diagram showing the change in product yield (actual results) by the conventional method and the final method, and FIG. 2(b) is a diagram showing the transition in the manufacturing yield η3 determined by the final method.

Claims (2)

[Claims] (1) From arbitrary cross-sectional images of the sintered body obtained by imaging with a CT scanner, images divided by the CT value level of each constituent pixel are synthesized, and after determining the area and perimeter of the images, A method for measuring the manufacturing yield of a sintered body, comprising measuring the manufacturing yield of the sintered body as a function of . (2) Composite images divided by the CT value level of each constituent pixel from arbitrary cross-sectional images of the sintered body obtained by imaging with a CT scanner, calculate the area and perimeter of the image, and then A method for measuring the manufacturing yield of a sintered body, characterized by measuring the manufacturing yield of a sintered body using the formula. η_1={1-(M/(M+N))}×100 η_2={1-k(L/N)}×100 η_3=η_1×η_2/100 where η_1: Degree of sintering [%] η_2: Crushing yield [%] η_3: Manufacturing yield N: Area of image with CT value level substantially equivalent to 2000 or more when tube voltage is 420 kv [mm^2
] M: Area of image with CT value level substantially equivalent to less than 2000 when tube voltage is 420 kv [mm^2
] L: Peripheral length of an image with a CT value level substantially equivalent to 2000 or more when the tube voltage is 420 kv [mm] k: Fracture coefficient [mm]