JPH10132724A - Measuring method for exudation amount oh matrix glass phase in molten refractory - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a measuring method by which the exudation amount of a matrix glass phase is determined quantitatively by polishing an exudation, which is generated from a refractory by a heating operation, so as to be removed, or adsorbing with an adsorption material so as to be removed, and measuring a change in the weight of the refractory. SOLUTION: First, a sample, whose weight is measured in advance, is placed on a substance, e.g. an alumina plate, which does not react with the sample, it is heated, an exudation, which is absorbed to the sample, is polished so as to be removed, the sample is dried, its weight is measuring again, and a change in its weight by a heating operation is determined quantitatively. A porous alumina refractory is desirable as refractory. Evaluation expression 1); exudation amount (wt.%)=(W5 -W6 )/W5 ×100, where W5 represents the dry weight of the sample before its heating operation and its polishing operation, and W6 represents the dry weight of the sample after its heating operating and its polishing operation. Secondarily, a sample whose weight is measured in advance is covered with a substance, e.g. a porous alumina plate, which is no reacted with the sample, it is used as the absorption material of an exudation, it is heated, it is cooled, the adsorption material is removed, its weight is measured again, and a change in the weight due to a heating operation in determined quantitatively. Evaluation expression 2); exudation amount (wt.%)=(W7 +W8 )/W7 ×100, where W7 represents the dry weight of the sample before its heating operation and its absorption operation and W8 represents the dry weight of the sample after its heating operation and its adsorption operation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for quantitatively measuring the amount of matrix glass phase exudation of a molten refractory containing a matrix glass phase.

[0002]

2. Description of the Related Art Refractory cast refractories are characterized by their chemical composition.
Refractories such as alumina-zirconia-silica type, alumina type, and recently high zirconia type can be classified. These refractories are obtained by melting, for example, in an electric arc furnace, pouring the molten metal into a mold, and then cooling and solidifying the molten metal to room temperature, so that it has a dense and developed crystal structure.
For this reason, these refractories are preferably used as furnace materials for glass melting tank kilns, and have excellent corrosion resistance and anti-glass contamination as compared with ordinary combined refractories.

[0003] However, these refractories contain a matrix glass due to their mineralogical composition. Alumina-zirconia-silica or some high zirconia refractories have a relatively large amount of matrix glass phase. The matrix glass phase is an indispensable component for each refractory, but at high temperatures, itself or its reaction product oozes out. This phenomenon causes glass defects such as knots, stones and blisters, directly or indirectly, to the molten glass, and reduces the productivity of the molten glass. In particular, alumina-zirconia-
This is remarkable for silica-based refractories.

Therefore, it is a good method to measure the amount of matrix glass leached in order to evaluate the refractory properties against glass contamination.

[0005] However, at present, it is hard to say that a quantitative method is used for the method of measuring the amount of matrix glass exudation. In general, the amount of exudation is evaluated by a change in volume due to heating (for example, Ceram. Eng. Sci. Proc. 10 p3
38-347 1989). In this method, for example, the following method is used. A sample having a diameter of 30 mm and a height of 30 mm is collected from the refractory ingot, and the volume is measured by the Archimedes method. Then, place the sample on a platinum plate at 1500 ° C.
For 16 hours using an electric furnace, and after cooling, measure the volume again by the Archimedes method. The exudation is evaluated by a change in volume due to heating, and is determined by the following equation.

[0006]

(Equation 1)

Here, W ₃ : weight of the sample before heating in water. W
₄ : Dry weight of sample before heating. W ₁ : weight of the sample in water after heating. W ₂ : dry weight of the sample after heating. Here, the volume refers to the sum of the volumes of the solid phase component and the closed pores.

[0008] Here, the amount of exudation is indicated by a positive value, and this value, that is, a larger volume increase indicates a larger amount of exudation.

However, this evaluation method has two major problems. For one thing, phenomenologically, exudation proceeds, and as exudate moves out of the refractory, the volume is reduced accordingly. However, the actual evaluation is the reverse evaluation, that is, the volume increase is large as the bleeding proceeds. They are,
Obviously inconsistent. The second is that the increase or decrease of closed pores (gas phase), which should not be the target of exudation, is the target of volume and is included in the amount of exudation, which causes the measurement to be ambiguous. Furthermore, during heating, closed pores before heating change to open pores,
Alternatively, since the open pores before heating can change to closed pores, the volume change is made more ambiguous. In addition, when zirconia is included, the volume change due to the transformation may not be negligible for the measurement. For the reasons described above, the method of evaluating the amount of matrix glass exuding by the change in volume due to heating cannot be said to be quantitative.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to provide a molten refractory containing a matrix glass phase, which is one of the most suitable methods for examining performance such as anti-glass contamination. The purpose is to provide a quantitative measurement method.

[0011]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and is a method for measuring the amount of matrix glass phase exudation by heating a molten refractory containing a matrix glass phase. An object of the present invention is to provide a method for quantifying the amount of exudation by changing the weight of a refractory.

The leaching phenomenon of the matrix glass is generally vaguely treated as “movement of the matrix glass out of the brick”. This is one reason that current measurement methods are not quantitative. Therefore, the exudation phenomenon is defined as follows. The leaching phenomenon of the matrix glass is, `` Matrix glass constituting the refractory or its reaction product, at the place where the refractory is installed,
Movement to the outside of the bulk volume or to the apparent volume by some chemical and physical action. "

In view of the problems of the above-mentioned current measurement method, based on the above definition, it can be seen that the amount of leaching is optimally determined by the change in weight of the sample due to heating.

The amount of leaching can be preferably determined by the following two methods as a change in weight due to heating, that is, a change in weight of the refractory from which the matrix glass exuded by heating has been removed. By applying this method, the amount of exudation can be measured
Alumina - Zirconia - is a refractory silica-based, or a part of the high zirconia (ZrO ₂ content 80~90wt%), but is not limited thereto.

[0015] First, a sample whose weight has been measured in advance is placed on a substance which does not react with the sample, such as an alumina plate, and heated to remove exudates attached to the sample, preferably by polishing using an abrasive, and then drying. This is a method of measuring the weight again and quantifying the weight change due to heating. The evaluation is performed by the following equation.

[0016]

(Equation 2)

Here, W ₅ : dry weight of the sample before heat polishing. ; W ₆ heating the dry weight of the polishing after the sample.

In this method, the shape of the sample is preferably a rectangular parallelepiped or a cube so as to facilitate polishing. Further, the size of the sample depends on the purpose of the measurement, but is preferably 30 to 100 mm on a side for handling. The material on which the sample is mounted must not be so dense that it does not chemically react with the sample and, especially when the amount of leaching is large, does not impede leaching from below the sample.

Considering both, a porous alumina refractory is desirable. In addition, regarding polishing of exudates, exudates are glass or glassy substances, and are easy to polish. However, it is necessary to be careful not to polish the sample, that is, not to polish the sample itself, and use alumina or silicon carbide as an abrasive. After polishing, it is necessary to clean the sample using an ultrasonic cleaner or the like.

The second is that a sample whose weight has been measured in advance is coated with a substance that does not react with the sample, for example, a porous alumina plate, which is used as an adsorbent for exudate, heated, cooled, and the adsorbent is removed. Is measured again to determine the change in weight due to heating. The evaluation is performed by the following equation.

[0021]

(Equation 3)

Here, W ₇ : the dry weight of the sample before heat adsorption. ; W ₈ heating the dry weight of the post-adsorption sample.

In this method, the shape of the sample is preferably a rectangular parallelepiped or a cube, but there is no problem even if it is a cylinder. Further, the size of the sample depends on the purpose of measurement, but is preferably 30 to 100 mm on one side (diameter or height) for handling. The sorbent must not only chemically react with the sample, but must also affect leachability (ie promote and inhibit leachability). In particular, a porous alumina fired refractory having a bulk specific gravity of about 1.5 is desirable. It is readily available because it is commercially available. If the adsorbent is dense, it does not serve as an adsorbent. Conversely, fibers and wool-like materials tend to react with the sample.

Alumina is the most suitable material from the viewpoint of reactivity with a sample and availability. Adsorbent is 5
The thickness is preferably 10 mm to 10 mm, and it is necessary to fix the adsorbent on the adsorbent using a platinum wire or the like so as not to peel off from the sample.

In the case of a high zirconia refractory having a ZrO ₂ content of 80 to 90 wt%, the amount of matrix glass leached under a load is measured from the viewpoint of relatively high content of matrix glass and creep characteristics at high temperatures. In some cases, it is necessary to measure the change in weight before and after heating under load by the above method. Particularly preferred is a method of adsorbing exudates by the latter method.

The heating method, heating temperature, and heating time in the measurement of the present invention described above may be set according to the use of the refractory.

[0027]

EXAMPLES Examples of the present invention will be specifically described below along with comparative examples, but the present invention is not limited to these examples.

An example of a method for preparing a sample used for the measurement of the present invention is described below. First, a predetermined amount of zircon desilicated, Bayer alumina, silica sand, and sodium carbonate were weighed and mixed, and then completely melted at 1900 to 2300 ° C. in a 500 kVA single-phase electric arc furnace using a graphite electrode. . This molten metal is embedded in silica / alumina balls or Bayer Alumina.
Hot water was poured into a 350 mm sand mold or graphite mold and allowed to cool to room temperature. As described above, ingots A, B, C, D, E,
A total of 7 points of F and G were obtained.

The ingots A, B and C are as follows:
Oxygen was blown into the molten metal at a rate of 30 ml / min for 1 minute in the latter stage of melting. Then, from the skin of the ingot,
Samples A, B, C, D, and D are cut and polished by cutting and polishing a cubic sample (or a cylindrical shape having a diameter of 30 mm and a height of 30 mm) having a side of 30 mm from a portion not including 0 mm.
E, F, and G were obtained. Table 1 shows the chemical composition (% by weight) and the specific gravity of the obtained sample. These are described in Examples 1 to 3.
The samples were taken at sites as close as possible to each other.

(Example 1) Cube-shaped samples A, B, C, D and E each having a side of 30 mm whose weight was measured in advance
Was placed on a porous alumina fired brick plate processed to 40 mm × 40 mm × 5 mm, and 15
Heat at 00 ° C. and 1600 ° C. for 48 hours and cool to room temperature. Next, exudates were removed by using silicon carbide (# 1000) as an abrasive, and ultrasonic cleaning was performed. In addition, 110
After drying at 24 ° C. for 24 hours, the weight was measured. The amount of leaching (% by weight) was determined by Equation 2. Table 2 shows the amount of exudation.

(Example 2) Cube-shaped samples A, B, C, D and E each having a side of 30 mm whose weight was measured in advance
Was covered with a porous alumina fired brick plate processed to 30 mm × 40 mm × 5 mm so as to be an adsorbent for exudates, and the sides were fixed with platinum wires. The coated sample was heated and cooled as in Example 1. Then, the coating was removed and the weight was measured. The amount of leaching (% by weight) was determined by Equation 3. Table 2 shows the amount of exudation.

(Example 3) For cylindrical samples A, F and G whose weights were measured in advance, an inner diameter of 30
mm, height 40 mm, diameter 30 mm on top and bottom,
A porous alumina fired brick plate processed to a thickness of 5 mm is coated so as to serve as an adsorbent for exudate, and the coated sample is subjected to a resistance heating electric furnace to which a load can be applied.
The mixture was heated for 16 hours while applying a load of kgf / cm ² and cooled to room temperature. Heated and cooled. Then, the coating was removed and the weight was measured. The amount of leaching (% by weight) was determined by Equation 3. Table 2 shows the amount of exudation.

(Comparative Example) Cube-shaped samples A, B, C, 30 mm on a side, which were previously dried and weighed in water,
D, E, F, and G were placed on a platinum plate, heated in a resistance heating type electric furnace at 1500 ° C. for 16 hours, and cooled to room temperature. The water and dry weight of the samples were measured.
The amount of exudation was determined by Equation 1. Table 2 shows the amount of leaching (% by volume)
Shown in

From Table 1, it can be seen that Examples 1 and 2 show substantially the same values, but Example 1 shows that
In particular, at 1500 ° C., a slightly lower value is shown. This is because, in Example 1, when exudates adhere to the sample and the exudates are pushed out of the sample, the exudates attached to the exudates are suppressed from exuding. On the other hand, in the second embodiment, newly generated exudation is not affected by the previous exudation, that is, adsorption of exudate is sequentially and selectively generated. However, these are exudation phenomena, whether the exudate moves out of the bulk volume,
It is a matter of interpretation as to whether it moves out of the apparent volume or not, and it does not affect the quantitativeness of exudation. If the amount of oozing is regarded as the oozing potential, the second embodiment is considered to be more excellent.

However, as compared with the first and second embodiments,
It can be seen that the reproducibility is unstable and the comparative example has poor quantitative performance.

From Example 3, it can be seen that the present invention can be preferably applied to the measurement of the amount of leaching under a load, especially in a high zirconia system.

Example 4 ZrO ₂ content of seed tile size 3
For 3 wt% products, 3 sides per side from within 15 cm
A 0 mm cubic sample was prepared and the amount of leaching was measured according to Example 2.
The amount of leaching at 600 ° C. for 48 hours was 1.2 on average, respectively.
It was 2 wt% (n = 8, standard deviation = 0.16) and the average was 4.68 wt% (n = 8, standard deviation = 0.50). This indicates that the present invention can quantify the amount of matrix glass leaching with good reproducibility.

[0038]

[Table 1]

[0039]

[Table 2]

[0040]

According to the measurement method of the present invention, the amount of matrix glass phase exudation of a molten refractory containing a matrix glass phase can be quantitatively and reproducibly measured. by this,
It will be possible to accurately evaluate the performance of these refractories, in particular, the pollution resistance to glass.

Claims (5)

[Claims] 1. A method for measuring the amount of matrix glass phase exudation due to heating of a molten refractory containing a matrix glass phase, the method comprising quantifying a change in weight of the refractory before and after heating. 2. The method according to claim 1, wherein the amount of exudation is determined by a change in weight of the refractory from which exudates generated from the molten refractory are removed by heating. 3. The method according to claim 2, wherein the exudate generated from the molten refractory by heating is removed by polishing or adsorbed and removed by an adsorbent, and the amount of exudate is determined by a change in weight of the refractory. 4. The method according to claim 3, wherein the adsorbent is a porous alumina refractory. 5. The method according to claim 1, wherein the matrix glass is exuded by heating under a load.