JPS62134541A - Method for measuring apparent specific gravity of porous body - Google Patents

Abstract

PURPOSE:To make it possible not only to measure apparent specific gravity but also to calculate a more accurate void ratio from the measurement of the true specific gravity of the same specimen, by imparting stable water supply capacity to a porous water absorbing material to wrap a water-containing specimen in said material and removing the surface water of the specimen with good reproducibility. CONSTITUTION:A specimen surface water removing instrument has a pair of two containers 1, 2 are preliminarily imparts moisture within a proper range to urethane foams to grasp a water-containing specimen 3 and the drain port 6 provided to the bottom part of the lower container 2 has a size discharging moisture in an amount equal to that of moisture absorbed from the surface of the specimen 3 by water-containing urethane foams. The specimen 3 dried and weighed is immersed in water to be defoamed by a vacuum apparatus and pressed for 4-5sec using the surface water removing instrument. By this method, the treatment of the specimen before measurement is finished and the measured specimen 14 is received in the reticulated specimen basket 12 suspended in water of the water tank 11 placed on a balance 10 at a definite position to perform measurement. A weight numerical value is divided by the specific gravity of water at the time of weighting to calculate the apparent volume of the specimen and the already measured dry wt. of the specimen is divided by said calculated value to calculate the apparent specific gravity of the specimen.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for quickly and accurately measuring the apparent specific gravity required for calculating the porosity of a porous body.

The porous body referred to in the present invention refers to iron ore for iron manufacturing.

Auxiliary raw materials, agglomerated minerals such as sintered ore and pellets.

These include coke, bricks, etc., and the present invention can be widely used for measuring their apparent specific gravity and porosity.

(Prior Art) Conventionally, the apparent specific gravity of porous bodies, such as iron ore and pellets that are raw materials for iron manufacturing, has been determined by the apparent specific gravity measurement method for iron ores (pellets) specified in JIS M 8718. Ta. In recent years, a pellet volume measurement method using an aqueous sodium oleate solution (Japan Society for the Promotion of Science, Ironmaking No. 5) has been developed.
4 Committee-1637) and JIS in the coke field.
Coke porosity measurement method specified in K 2151 and its rapid method (Coke Circular-985 (+
982)) has been attempted. As there is no standard method for measuring apparent specific gravity or porosity of sintered ore, attempts have been made to measure porosity by polishing the sample and analyzing images of its surface.

(Problems to be Solved by the Invention) Methods related to measuring the apparent specific gravity of raw materials for iron manufacturing have been described above as conventional techniques, but each method has the following problems.

That is, according to the method for measuring the apparent specific gravity of iron ores (pellets) specified in JIS M 8718, the large pore diameter of sintered ore cannot be measured as porosity, and it is difficult to measure the apparent volume. Because mercury is used in this process, problems have been pointed out in terms of the working environment and sample processing after measurement.

In order to solve problems in the working environment related to mercury, there is a method for measuring the volume of pellets using an aqueous solution of sodium olein. This method is a body 11 measurement method limited to pellets. If this method were applied to the volume measurement of sintered minerals, a problem would arise in the method of wiping off sodium oleic acid and kerosene. That is, since the wiping method in this method involves filling the container with absorbent cotton or gauze to absorb the solution on the surface of the sample, it is necessary to replace the filled absorbent material. Furthermore, since the container is not provided with a discharge hole for the absorbed solution, the absorbent material cannot have a constant absorption capacity.

Furthermore, since the surface shape of sintered ore is extremely complex, it is difficult to uniformly remove the solution on the sample surface using this method.

In the field of coke, porosity measurement is carried out according to JIS K 2151, but it requires a lot of effort, such as cutting out a sample and boiling it. Therefore, in recent years, a rapid method (Coke Circular 985 (1982)) has been implemented.In this method, only the surface water adhering to the sample after degassing under reduced pressure in water is removed, while the water in the pores is left intact. After processing the sample, the apparent volume of the sample is measured by suspending it in water, and the apparent specific gravity of the sample is calculated.

In the case of coke, the method used to remove surface water is to rotate the sample once on a water-containing sponge. However, in the case of sintered ore, which has irregularities of various sizes on its surface, surface water cannot be removed with high reproducibility using the same method as for coke, and the apparent specific gravity is measured to determine the porosity. Since sintered ore has large pore diameters, unevenness, and a complex surface shape, attempts have been made to determine porosity using image analysis. However, polishing costs are high and it takes a lot of time.

As mentioned above, as an example of measuring the apparent specific gravity of sintered ore, the method is applied to conventional coke and iron ore (pellets) for porous bodies with large pore diameters and complex surface shapes. There are problems with accuracy when using image analysis methods, and problems with efficiency such as cost and measurement time when using image analysis methods.

(Means for Solving the Problems) In order to solve the problems, the present invention provides a method applied to coke (Coke Circular 985 (1999)).
82), we attempted to provide a new method for measuring the apparent specific gravity of porous materials such as sintered ore by finding a method to uniformly remove surface water from a sample with good reproducibility after degassing in water. , the gist of which is that after weighing a dry porous body, it is immersed in water to degas it under reduced pressure, and then supported or housed in two supports each having at least one drainage port, In addition, water on the surface of the sample is removed by sandwiching the degassing sample with a porous water absorbing material containing a predetermined appropriate amount of water, and then the sample is suspended from above in a water tank placed on a balance. , calculate the apparent volume of the sample by dividing the weight increment displayed on the balance by the specific gravity of water,
This method further calculates the apparent specific gravity of a porous body by dividing the dry weight of the sample by the apparent volume.

The present invention will be explained in detail below.

The present inventors focused on the conventional measurement method applied to coke, and applied this method to porous bodies such as sintered ore, in the process of researching a method for stable removal of surface water. We discovered that a porous water-absorbing material with a certain amount of water in advance and sandwiching a measurement sample in it can exhibit a stable water supply ability. The progress of research to take advantage of this property will be explained using an example of using urethane foam as a porous water absorbing material.

In order to examine the degree of surface water removal from the sintered ore after underwater defoaming while changing the water content of the urethane foam, the water remaining on the sample side was measured, and the results shown in Figure 1 were obtained. As a result, it was found that urethane foam exhibits extremely stable water absorption ability when it contains 5 to 20% water by volume.

On the other hand, when a large number of water-containing samples are dehydrated in succession, water is transferred from the measurement sample to the urethane foam, and the water content in the urethane foam increases. As is clear from Figure 1, as the moisture content of urethane foam exceeds 20% and the moisture content increases, the residual moisture in the measurement sample also increases, making stable dehydration difficult when performing continuous measurements. .

Therefore, in order to remove surface water stably in continuous processing, the water content of the urethane foam must be constantly maintained at 5% by draining the excess water absorbed by the hydrated urethane foam from the sample surface.
It is necessary to maintain it within ~20%. Furthermore, in order to stabilize the amount of water absorbed by the urethane foam, it is necessary to wrap the entire sintered ore after underwater defoaming in the hydrated urethane foam with as constant a force as possible for a certain period of time. In order to meet these requirements, the inventors of the present invention have developed a sample surface water removal device as shown in FIG. 2, as an example. The two containers 1 and 2 were constructed as a pair so that their openings matched, and the urethane foams were housed in the container so that the urethane foams 4 and 5 were exposed in a protruding manner at the openings. In this structure, the urethane foam is preliminarily moistened within an appropriate range, and a water-containing sample 3 is sandwiched between the urethane foams and a pressing operation is performed for a certain period of time as shown in the figure.

Furthermore, the surface water removal device shown in FIG. 2 is provided with a drain port 6 at the bottom of the lower container 2 in order to stabilize the water content of the urethane foam and stabilize the surface water removal effect of the measurement sample. . In addition, the size of the drainage port is selected so that the amount of moisture equivalent to that absorbed by the hydrated urethane foam from the surface of the sample is discharged. Just press it for an appropriate amount of time.

The following describes the results of a study on the appropriate moisture content of urethane foam, fluctuations in moisture content due to continuous use, appropriate pressing time, etc. using the sample surface water removal device shown in FIG.

Four holes each having a diameter of 1.5 mm were bored as drainage ports 6 in the sample surface water removal device shown in FIG. Using this, mainly 2
An example in which sintered ore with a grain size of 0±1a++s was processed and measured one by one will be described. First, the results of examining the appropriate moisture content of the urethane foam contained in the container are shown in Figure 4. According to this method, the degree of water removal from the sample surface after defoaming by immersion in water is mainly due to the moisture remaining in the pores of the sample. Since it can be confirmed by the amount, it is assumed that the IT value when the urethane foam that has been soaked in water is lightly squeezed is 1.0, and the moisture content of the sample that has been subjected to surface water removal treatment in this state is the same <1.0. The changes in water content and water content in the water-absorbing material were plotted in terms of weight ratio.

FIG. 4 clearly shows the relationship between the movement of moisture in the water-absorbing material and the surface water removal effect when the surface water removal operation is repeated for the same sintered ore. That is, even if the same urethane foam is used, the saturated water content is different in the upper and lower volumes, and as the water content becomes stable in the upper and lower urethane foams, the effect of removing water on the sample surface becomes stable. From this, when using urethane foam as a porous water-absorbing material, if the moisture content in the upper container, where there is little variation in moisture content, is determined by the volume ratio to the urethane foam 4, the appropriate moisture content is 5 to 10 Vol.
! It turned out to be.

Next, the initial moisture content in the upper container was adjusted to a range of 5 to 10 Vol, and the appropriate amount of moisture in the lower container was determined.

The results are shown in Figure 5. Here, the surface water of the water-containing sample is removed and weighed while changing the water content in the lower container in the volume ratio with the urethane foam 5, and this is repeated to determine the water content on the sample side. The variation of was plotted. Based on Fig. 5, the appropriate moisture content in the lower container was determined by the volume ratio to the urethane foam 5, and the appropriate moisture content was 10 to 20 Vol.
It turned out to be.

Furthermore, assuming that a large number of samples will be used continuously,
200 pieces of sintered ore with a particle size of 20±1II11 were immersed in water for defoaming, and the initial moisture content in the upper and lower containers was adjusted within the range of appropriate moisture content determined from Figures 4 and 5, and surface water was sequentially removed. . As shown in FIG. 6, the results revealed that the degree of wetness of the urethane foam was stable over a long period of time.

In addition to the above considerations, we also investigated the effect of absorption time by pressing. The results are shown in Figure 7, where 20±1■
Three pieces of sintered ore with grain size and one pellet with grain size of 12±1 mm were used as samples, and 7Vo1. Palette, lower urethane foam 5 to 1
Using a surface water removal device moistened with 7 Vol.
Changes in the amount of water remaining in the sample were investigated while changing the time in 1 second increments. As a result, it was found that all sintered ores stabilized when pressed for 4 seconds or more, and pellets became stable quickly after 1 second of pressing. Since the water removed from the pellet is considered to be surface water, the reason why the water content decreases in the case of sintered ore can be considered to be that the pore water formed on the surface changes depending on the absorption time. Therefore, the absorption time by pressing is appropriate for 4 seconds or more. Thus, the present invention enables stable sample processing before measurement by determining the absorption method of sample surface water, absorbent material moisture content, and absorption time, and improves the accuracy of measuring the apparent volume of a sample in water.

The apparent specific gravity measurement process of the present invention based on the above-mentioned technical means will be described below according to the measurement procedure. Mazu,
The sample is dried and weighed, immersed in water, reduced in pressure by a vacuum device to, for example, ITarr, and degassed, preferably for 20 minutes. Such a sample is wrapped between two porous water-absorbing materials and pressed for 4 to 5 seconds using, for example, a surface water removing device shown in FIG. As mentioned above, when urethane foam is used as the water absorbing material, stable water absorption ability is exhibited by adjusting the water content to 5 to 20 VOl, X, so that the surface water of the water-containing sample is uniformly removed here. After finishing the sample processing before measurement, the apparent volume of the sample is measured using the apparatus configured as shown in FIG. The measurement sample 14 is placed on the balance 10
At a fixed position underwater in the aquarium 11 placed on the stand 15. Stopper 16. The sample is stored in a mesh-like sample basket 12 suspended via a string 17 and pulleys 18 and 19, and measured. In this method, a sample basket with a large mesh was used to prevent air bubbles from adhering during underwater weighing. The apparent volume of the sample is calculated by dividing the thus weighed value by the specific gravity of the water at the time of weighing, and the apparent specific gravity of the sample is calculated by dividing the already measured dry weight of the sample by this apparent volume. It is.

(Function) The present invention is most characterized in that the porous water-absorbing material contains an appropriate amount of water in advance, and the sample is sandwiched from both sides to remove water on the surface of the sample. Taking FIG. 2 as an example, an upper bowl-shaped container 1 with one end open and a lower bowl-shaped container 2 are connected by a removable hinge 7 so that the openings match, forming a pair, and each container has a It is filled with porous elastic water-absorbing material, ie, urethane foams 4 and 5, impregnated with 20 vol of water, and has a structure in which the entire sample 3 can be wrapped around it by raising the central part thereof in an exposed manner. 8 is a leg of the lower container 2, and 9 is a knob of the upper container l. A drainage port 6 is provided at the bottom of the lower container 2 so that excess water absorbed from the sample surface is drained out of the water-absorbing material in accordance with the time when the upper and lower containers are pressed. In the sample processing container configured as described above, the surface water of the water-containing sample is absorbed by the urethane foam and moved downward to the drain port by pressing for 4 to 5 seconds. Hydrous urethane foam has an extremely strong water retention capacity of 30 to 40 Vo1.
It has the characteristic that it does not drip even if it is soaked with $0.00 of water, but water only drips after it is pressed. In addition, the restoring force of urethane foam is more than 0, which is effective for increasing reproducibility.
By keeping water in and out constant, the water absorption ability of the urethane foam is stabilized, and after pressing, it easily restores its shape to envelop the water-containing sample and can be pressed with a constant force, improving reproducibility in surface water removal. The apparent specific gravity measurement method of the present invention will be put into practical use by establishing the surface water removal method developed to improve measurement accuracy.

As mentioned above, the method of the present invention has been explained using as an example the case where urethane foam is used as the porous water-absorbing material. Other porous materials that have water absorbing properties can be used in the same manner. These porous water-absorbing materials are capable of stably removing surface water, while at the same time providing elasticity so that excess water absorbed from the sample can be easily discharged during pressing, and the shape can be easily restored after pressing. is desirable.

Furthermore, when adopting these porous water-absorbing materials, consider in advance the appropriate amount of moisture to be contained and the optimal pressing time, as explained in the example of urethane foam above, depending on the characteristics of each material. It is necessary.

Furthermore, as shown in FIG. 2, an example was explained in which a device having a structure in which a porous water-absorbing material was housed in a container was used as a surface water removal device, but the present invention is not limited to this FIG. Instead, it is also possible to prepare two pieces of water-absorbing material with one side of the absorbent material held on a suitable support, and use the two supports to press the absorbent material surfaces facing each other. It is sufficient to have a structure that allows 2Ml porous materials to be pressed from the back side facing each other with as constant a pressure as possible, and a discharge port that can discharge excess water squeezed out from the water-absorbing material during pressing.

Furthermore, although sintered ore was mainly explained as a measurement sample, as mentioned above, the present invention is applicable to iron ores for iron making, auxiliary raw materials, agglomerated products such as pellets, coke, and bricks, in addition to sintered ore. Furthermore, it can be easily applied to porous substances (porous bodies) such as non-ferrous minerals, and the object to be measured is not particularly limited as long as it is a porous body.

(Example) The apparent specific gravity is measured to calculate the porosity of the sample.
The apparent ratio N measurement method of the present invention differs from the coke rapid method in the means for removing surface water from a water-containing sample. A method of removing surface water by one rotation on a water-containing sponge, which is adopted in the case of coke, is called conventional method 1, and a method without degassing treatment by immersion in water is called conventional method 2, and compared with the method of the present invention in terms of porosity. The measurement results are shown in Table 1. The same sintered ore with a grain size of 20±1 square meters was used as the sample, and the sample was treated with the surface water removal device shown in FIG. 2 before measurement. Here, four holes with a diameter of 1.5H were provided as drainage ports, urethane foam was used as the porous water absorbing material, and the upper urethane foam was made of 7Va1.
．． ! , Below! The urethane foam was given an initial moisture content of 17 Vol, $. First, measure the dry weight, press the immersed defoamed sample for 5 seconds to remove surface water, then measure the apparent specific gravity using the measurement procedure described above, and calculate the porosity based on the measurement results. did. In addition, for the method of the present invention and conventional method 1, 20 repetitions were performed to compare the measurement accuracy.
The results of multiple measurements are shown.

Table 1 According to the method of the present invention and the conventional method 1, the apparent volume of the sample is larger and the apparent specific gravity of the sample is measured to be smaller than that of the conventional method 2 which does not perform degassing treatment by immersion in water. Therefore, the porosity of the sample is calculated to be high. In this case, the porosity is determined by the following formula.

Here, P: Porosity (X) S: Apparent specific gravity S: True specific gravity As shown in Table 1, the average porosity in the case based on the method of the present invention and the conventional method I is almost the same, but in the case based on the method of the present invention is superior in both repeatability and maximum/minimum difference in repeated measurements.

Next, regarding the porosity of sintered minerals determined based on the results measured by the present invention, the mercury method (
Figures 8 and 9 for comparison with JIS M 871B)
The measurement results are shown in Fig. 8.As can be seen in Fig. 8, the porosity of the fired pellets indicated by the 0 mark and the briquettes indicated by the 0 mark are almost the same in both the case based on the method of the present invention and the case based on the mercury method. Here, briquettes are formed by molding raw materials for sintering and firing with gas at 1200 to 1400°C to change the porosity. On the other hand, for sintered ore, as shown in Figure 9.

The same - When sintered ore is first measured using the method of the present invention to determine the porosity, and then dried and then measured and compared using the mercury method. 1. The porosity based on the method of the present invention is higher than the porosity using the mercury method. It's getting expensive. This indicates that the porosity measuring method according to the present invention can measure larger pores than the porosity measuring method based on the mercury method.

(Effects of the Invention) As described in detail above, according to the present invention, stable water supply ability is given to the porous water-absorbing material to enclose a water-containing sample, water on the surface of the sample is removed with good reproducibility, and apparent specific gravity can be measured. This allows for high precision and very little wear and tear on the porous water-absorbing material, allowing continuous and rapid processing. In particular, when compared with image analysis methods, the method of measuring porosity using the method of the present invention is extremely superior in terms of cost and efficiency. In addition, compared to the mercury method, it is possible to measure larger pore diameters, and since water is used as the measurement solution, it is not only possible to re-measure, but also the true specific gravity can be measured with the same sample, resulting in more accurate porosity. can also be found. Furthermore, in terms of measurement work, there is no need to worry about the troubles that occur when mercury is used as the measurement liquid, and the measurement operation is extremely simple.

Incidentally, when measuring a large porous body as it is or when measuring a plurality of samples at the same time, the same effect can be obtained by using the surface water removal device shown in FIG. 2, enlarged as necessary.

[Brief explanation of drawings]

Fig. 1 is a characteristic diagram regarding the water absorption capacity of water absorbing material (urethane foam), Fig. 2 is a vertical cross-sectional view showing a sample surface water removal device according to an embodiment of the present invention, and Fig. 3 is an overall schematic diagram of the apparent specific gravity measuring device. , Figure 4 is a diagram showing the relationship between the change in moisture in the water absorbing material and the surface water removal effect when the surface water removal device is repeatedly used.
Figure 5 is a diagram showing the appropriate amount of moisture in the water-absorbing material in the lower container.
Figure 6 is a diagram to confirm the appropriate amount of water in the water absorbing material in the upper and lower containers, Figure 7 shows the sample surface water absorption time and its effect by press operation, and Figures 8 and 9 are diagrams showing the mercury method and the pending results. It is a figure showing measurement results as a comparison in terms of porosity. 1.2... Container, 3... Sample, 4, 5... Urethane foam, 6... Drain port, 10... Balance, 1
1...Aquarium, 12...Sample basket, 13...Water, 1
4...Sample.

Claims (1)

[Claims] 1) After weighing the dry porous material, it is immersed in water to degas it under reduced pressure, and then held or held in two supports each having at least one drain port. The water on the surface of the sample is removed by sandwiching the vacuum-defoamed sample between porous water-absorbing materials containing a predetermined appropriate amount of water, and then the sample is placed in a water tank placed on a balance. Hang it from above and calculate the apparent volume of the sample by dividing the weight increment displayed on the balance by the specific gravity of water, and then calculate the apparent specific gravity of the sample by dividing the dry weight of the sample by the apparent volume. A method for measuring the apparent specific gravity of a porous body. 2) The method according to claim 1, in which urethane foam is used as the porous water absorbing material. 3) The method according to claim 1, wherein a container is used as a support.