JP3364053B2 - Evaluation method of strength of porous body - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for evaluating the strength of a porous body, which can directly measure the strength of the porous body (in particular, the strength of the pore wall of coke for iron making).

[0002]

2. Description of the Related Art As is well known, the coke strength is industrially measured by a drum method or a tumbler method as shown in JIS K2151. In any of these methods, a 10 kg coke sample is charged into a prescribed device equipped with a rotating container, rotated at a prescribed speed for a prescribed number of times, and then sieved with a prescribed sieve to obtain each. Coke strength is evaluated by calculating the mass for each category and using the percentage added to the sample as an index.

In addition, as a non-industrial method, a coke sample sized to 1 to 2 mm and several iron balls are
There is a method (microstrength) in which the sample is sieved with a desired sieve and rotated after being put in a mold-shaped cylinder at the same time, and the sample is sieved with a desired sieve. There is a method in which a sample is cut out and a load is applied in the radial direction, and the tensile strength (indirect tensile strength) is obtained from the load at which the sample is broken and the sample shape.

[0004]

However, these conventional methods for measuring coke strength are (a) a large amount of sample, (b) many steps are required to obtain the results,
(c) There is a difference in pulverization characteristics depending on the pore structure of the sample,
That is, since the amount of pulverization is used for evaluation, the amount is expressed by the product of the number of powders and the weight per powder. Even if the index is the same, the content of the generated powders is different, so the evaluation may not be the same when using a blast furnace. However, (d) the coke sample has strength anisotropy in the directions parallel and perpendicular to the furnace wall, which affects the results.

Under such a background, the present invention directly measures the strength of the porous body (in particular, the strength of the pore wall of the coke for iron making) based on a mechanism completely different from the conventional method as described above. It is an object of the present invention to provide a method for evaluating the strength of a porous body that can be used.

[0006]

Means for Solving the Problems A method for evaluating the strength of a porous body of the present invention is to put a porous body sample in a closed pressure vessel, fill it with a liquid medium having a small elasticity, and gradually pressurize the liquid medium. Perform a test to destroy the pore wall of the sample by adding
It is characterized in that the strength of the porous body is evaluated based on the measurement information at that time.

The present invention will be described in detail below.

The porous material applicable to the evaluation method of the present invention includes coal coke, petroleum coke, char, activated carbon, which are used for iron making, catalyst carriers, adsorbents, batteries and the like.
Examples thereof include carbon materials such as graphite, various ceramic-based porous bodies, various resin-based porous bodies, and sintered bodies thereof. Particularly, iron-making coke, which requires strict property control, is important.

In the present invention, a test is carried out in which a porous sample is placed in a closed pressure vessel and is filled with a liquid medium having a low elasticity, and the liquid medium is gradually applied with pressure to destroy the pore walls of the sample.

As the liquid medium having a small stretchability, a liquid whose volume change is small even when pressure is applied, and is an inert liquid which does not exhibit dissolution or swelling behavior in the porous body used for the measurement. can give. A typical example of such a liquid medium is mercury, and in addition, a fluorine-based solvent (perfluorocarbon), silicone, etc. can be used.

The pressure vessel is a vessel capable of withstanding a pressure higher than the pressure that breaks the pore walls of the porous body to be measured, eg, 2 when the porous body is a coke for iron making.
A container capable of withstanding a pressure of about 0000 to 30,000 psia (1 psia is 70.4 g / cm ² ) is used.

When the above test is conducted, the liquid medium penetrates into the pores (open pores) having a diameter corresponding to the pressure, and when the pressure is further increased, the pore wall forming the closed pores is destroyed and the liquid medium is removed. Penetrate into closed pores.

Therefore, the strength of the porous body can be evaluated qualitatively and quantitatively based on the measurement information of the above test. A typical example of the measurement information is the relationship between the press-fitting pressure or the pore size correlated therewith and the liquid-medium press-fitting amount.

Next, the evaluation method of the present invention will be described more specifically with reference to the drawings. FIG. 1 shows a conceptual diagram of the pore wall strength measuring method according to the present invention.

First, a cut coke piece (an example of a porous body) is put in a closed pressure vessel, the inside of the vessel is filled with a liquid medium having a low elasticity such as mercury, and the medium is gradually pressurized. (See Figure 1 (A))

As the pressure rises, the pressurizing medium is introduced into the open pores of the coke, which is a porous body (including open pores penetrating both ends, open pores open at one end, and closed pores closed by the pore walls). It enters depending on the pressure and the pore size, but since it is closed in the closed pores, the medium does not enter unless the pore walls are destroyed. (See Figure 1 (B))

When the pressure further rises, the wall forming the closed pores receives a force from the outside of the closed pores (open pore side) toward the inside of the closed pores, and when the pressure reaches a certain pressure, it cannot bear the pressure. The wall is destroyed and the pressurized medium penetrates into the closed pores. The pressure at this time corresponds to the strength of the destroyed pore wall. (See Figure 1 (C))

When the pressurizing medium infiltrates into each hole under such a series of pressurizing conditions, the infiltration of the medium into the sample pores can be detected by the displacement of the piston in FIG. 1 (A). Therefore, if it is possible to distinguish between the infiltration of the medium into the open pores and the infiltration of the medium due to the destruction of the pore walls of the closed pores, the pressure at which the medium penetrates into the closed pores, that is, when the pore walls are destroyed The pressure distribution (pore wall strength distribution) can be measured.

[0019]

The above method is based on a mechanism completely different from the conventional method described in the section of the prior art. According to the method of the present invention, it is possible to measure with a very small amount of sample, and it is possible to directly measure the strength of the pore wall of the porous body such as the coke for iron making (in other words, the strength of only the substrate). Further, by measuring this strength, it becomes possible to quantitatively understand the wear strength of the coke, which indicates peeling of the pore wall. In addition, the method of the present invention is not affected by the anisotropy of strength such as coke.

An apparatus capable of simultaneously measuring the pressure of mercury injection and the amount of pressure injection into the porous body in order to measure the distribution and amount of the pore diameter of the porous body is known as a mercury pore meter. The application of the device to the destruction of the pore wall of a porous body and the measurement of its pore wall strength has been found according to the invention.

[0021]

EXAMPLES The present invention will be further described with reference to examples.

<Apparatus Diagram and Flow Diagram> FIG. 2 is an explanatory view schematically showing an example of a measuring device (using a mercury pore meter) and a measuring flow using the same when carrying out the present invention.
FIG. 3 is a perspective view showing an example of a measuring cell for a mercury pore meter.

<Measurement apparatus> The strength of a coke for iron making, which is an example of a porous body, was measured using a mercury porosimetry type mercury pore meter (mercury porosimeter) using mercury as a pressure medium.

The mercury porosimeter is a device capable of simultaneously measuring the pressure of mercury injection and the amount of pressure injection, and its principle is that when mercury is pressed into a porous body, a fine diameter of a size corresponding to the pressure is used. The intrusion of mercury into the holes (the higher the pressure,
Penetrates into smaller holes). According to this mercury pore meter,
It is possible to measure the pore size distribution and amount of about 500 μm to 60 Å. That is, the pressure can be converted into the pore size. Although such a measurement method only reveals the existence and distribution of the pores, in the present invention, the pressure is increased until the pore walls are destroyed, and the penetration of the medium into the open pores and the destruction of the medium by the pore wall destruction It is designed so that it can be distinguished from infiltration.

<Measurement Flow> Using the above-mentioned mercury pore meter, measurement was carried out in a pressure range of about 0.5 to 30,000 psia. The measurement flow (measurement procedure) is as follows. 1. Measure the sample weight (to give the result per unit weight). 2. Put the sample in the measuring cell. 3. Degas and depressurize the inside of the measurement cell. 4. Mercury is injected into the measurement cell in a depressurized state (measuring large pores and monitoring the amount of mercury injection). 5. Set the measuring cell (filled with mercury) in the pressure vessel of the high pressure device. 6. Fill the pressure vessel with oil. 7. The pressure in the pressure vessel is gradually increased by the pressure device, and at the same time, the pressure and the amount of mercury injected into the cell are monitored. 8. Analyze the measurement result (pressure ~ mercury injection amount)

<Examples and Results> Example 1 A coke piece cut out to a diameter of 10 mm and a thickness of 3 mm was used as a porous body sample, and the relationship between the pore diameter and the amount of mercury injected was determined according to the above apparatus and flow. The measurement results are shown in FIG.

Example 2 A porous body sample prepared from the same coke block as in Example 1 but pulverized to a particle size of 74 μm or less about 1 g
Was used to determine the relationship between the pore size and the mercury intrusion amount according to the above apparatus and flow. The measurement result is shown in FIG.

<Discussion> In FIG. 4 showing the result of Example 1, 10 ² to 10 ⁴ Å (0.01 to 0.1 μm)
m) and 10 ⁵ to 10 ⁶ angstrom (10 to 100
There is a peak at μm).

On the other hand, in FIG. 5 showing the results of Example 2, 2 × 10 ⁵ to 4 × 10 ⁵ angstroms (20 to
Although peak sharp is seen 40μm), 10 ² ~10 ⁴ Å peaks as in Example 1 is hardly observed.

From these, the following can be understood. (1) If the peak of 10 ² to 10 ⁴ Å in Example 1 is due to pores, the sample of Example 2 is sufficiently larger than these (10 ² to 10 ⁴ Å <<<< 74 μm). It can be judged that the sample contains pores of 10 ² to 10 ⁴ Å. (2) However, despite the above (1), 10 ² to 10
^{Since the 4} Å peak is not seen in Example 2, it can be judged that this peak in Example 1 is due to the destruction of the pore wall. (In addition, 2 of Example 2
The peak of × 10 ⁵ to 4 × 10 ⁵ angstroms indicates a gap between sample particles, which usually occurs when a powder sample is measured by a mercury porosimeter. )

[0031]

According to the method of the present invention, it is possible to measure with a small amount of sample, and it is possible to directly measure the strength of the pore wall (strength of only the substrate) of the porous body such as the coke for iron making. Also, by measuring this strength, it becomes possible to quantitatively understand the wear strength of coke that represents peeling of the pore wall, and it is not affected by the anisotropy of strength such as coke. The effect is played.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of a pore wall strength measuring method according to the present invention.

FIG. 2 is an explanatory view schematically showing an example of a measuring device (using a mercury pore meter) and a measurement flow using the same when carrying out the present invention.

FIG. 3 is a perspective view showing an example of a measuring cell for a mercury pore meter.

FIG. 4 is a graph showing a measurement result in Example 1.

FIG. 5 is a graph showing measurement results in Example 2.

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-59-97035 (JP, A) JP-A-57-144443 (JP, A) JP-A 1-225693 (JP, A) JP-A 58- 173451 (JP, A) Nishimura, Hiramatsu, Asada, Evaluation of pore wall strength of coke for metallurgy, Coke circular, Japan, Japan Energy Society, December 25, 1995, Vol. 44, No. 4, p. 176- 180 (58) Fields surveyed (Int.Cl. ⁷ , DB name) G01N 3/12 G01N 33/00 JISST file (JOIS)

Claims (3)

(57) [Claims] 1. A test in which a porous sample is placed in a closed pressure vessel and filled with a liquid medium having a small elasticity and a pressure is gradually applied to the liquid medium to destroy the pore walls of the sample. A method for evaluating the strength of a porous body, characterized in that the strength of the porous body is evaluated based on the measurement information. 2. The strength of the pore wall of the porous body is quantitatively evaluated based on the relationship between the press-fitting pressure or the pore diameter correlated therewith and the liquid medium press-fitting amount in the measurement information. The evaluation method according to claim 1. 3. The evaluation method according to claim 1, wherein the porous body is coke.