JPS589064B2 - Manufacturing method of jade-like artificial stone - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a technology for utilizing waste from the iron and steel industry, and in particular to technology for utilizing slag from the iron and steel industry, and in particular to the use of artificial stones (such as imitation jewelry and This invention relates to a method for producing decorative stones such as marble.

Blast furnace slag is discharged as a by-product of the steel industry in extremely large amounts, and various improvement technologies have been proposed against the backdrop of the contemporary demand for resource conservation.

The present invention has been made as part of these efforts, and aims to provide a method for inexpensively and rationally manufacturing high-grade artificial stone obtained using blast furnace slag as the main raw material.

As a method for manufacturing artificial stone from waste slag, for example, Japanese Patent Application Laid-open Nos. 151-713-1982 and 4521-1987 are known, but the present invention proposes and discloses a method for manufacturing artificial stone that is different from these. The main raw material is blast furnace slag, to which CaF2, Cr20a, and carbon are added, which is melted and solidified, and then cooled and/or reheated.
The gist of the present invention is to crystallize aF2 and color it green to obtain a green, milky-semitransparent or milky-opaque artificial stone with excellent decorative functions.

The present inventors have been conducting various research for some time based on the idea that it is possible to provide beautiful artificial stone with a bright green color using blast furnace slag as a raw material. A method of using blast furnace slag as it is and appropriately setting physical conditions such as melting conditions and cooling conditions; ■ A method of blending appropriate auxiliary raw materials with blast furnace slag to improve the quality of artificial stone from the standpoint of component composition; ■ We have conducted repeated experiments on a method of combining the above-mentioned (1) and (2) to improve the quality of artificial stone from both the component composition and physical manufacturing conditions.

In the process, the inventors confirmed that as long as blast furnace slag is used as a raw material, there is a limit to the quality of the artificial stone that can be obtained, no matter how the physical conditions of manufacturing are adjusted. In order to obtain high-quality artificial stone, we decided that the optimal composition and manufacturing conditions for artificial stone should be clarified.

Based on this judgment, the present inventors prepared artificial stones with different compositions by blending various oxides and ores with blast furnace slag, and compared their quality.

As a result, products containing 7 to 30% of CaF2 (same as 2 or less by weight) and 3 or less of Cr203 as essential components, and to which 0.1 to 1 part of carbon was added during production,
It was confirmed that this material exhibits superior quality compared to artificial stones with compositions outside these ranges.

In other words, in order to obtain high-quality artificial stone, the conventional method of using blast furnace slag as a raw material is not sufficient, so it is necessary to mix an appropriate amount of CaF2 according to the component composition of blast furnace slag and adjust the component composition appropriately. There is a need.

Especially since CaF2 is hardly contained in blast furnace slag,
It is essential to actively incorporate this into blast furnace slag.

In other words, CaF2 exhibits a special function of emulsifying the artificial stone, and is the base for giving it a brighter color (milky white) compared to the conventional artificial stone that only recrystallizes the matrix, which tends to be dark in color. can be molded.

Furthermore, it has the effect of lowering the melting point of the CaF2 raw material, and along with this, ■ No special heat resistance is required for the melting furnace or melting crucible, and commercially available products can be used.■ Rapid temperature drop during the casting process. You can also enjoy the following effects: 1. The cost of the heat source during melting is reduced.

Although it is of course possible to use a pure product as CaF2, fluorite is the most common in consideration of industrial efficiency.

By the way, as a method of adjusting the color tone of artificial stone, a method of adjusting the crystallization rate is known as shown in Japanese Patent Application Laid-Open No. 15173/1983.

Therefore, the present inventors experimentally confirmed the influence of the crystallization rate on the artificial stone having the above-mentioned preferable component composition.

As a result, for components other than CaF2 among the artificial stone constituents, almost no correlation was observed between crystallization rate and quality.

However, as for CaF2, its crystallization rate seems to have a significant effect on the emulsification of the entire artificial stone, and in order to achieve emulsification, the crystallization rate of CaF2 should be at least 2 or more. It was confirmed.

Further, the green coloring agent Cr20s can adjust the shade of green almost linearly up to about 3 parts, but becomes saturated when the amount is 3 parts or more.

In addition, when coloring in the jade tone (bright light green) of the present invention, it is desirable to add 0.1 to 0.7% of ACr203.

By the way, when we tried to add Cr203 to blast furnace slag to give it a jade-like color, we encountered an unstable coloring state in which it sometimes appeared bright green, and other times exhibited a brownish green (giving a dirty look). However, a major problem arose in terms of reproducibility.

The cause of this unstable coloring is thought to be the presence of Fe203 in the raw material, and as long as blast furnace slag is used as the main raw material, it is impossible to completely remove Fe203 in advance.

Therefore, in the present invention, as a result of repeated experiments in order to achieve stable jade-like coloring with Cr203 regardless of the presence or absence of Fe203 in this raw material, we found that 0.0% carbon was added to the raw material.
By adding 1% to 1%, preferably 0.2% to 0.8%, it was possible to obtain a stable coloring with a gray tone.

In the present invention, blast furnace slag is used as the main raw material, but if necessary, SiO2, CaO, Al203, etc. may be appropriately blended, and the main raw material components are Si02 30-41, Ca0
35-45%, Al203 12-20%, and also contains some amounts of MgO, MnO, S, TiO2, etc.

Next, the process of manufacturing the above-mentioned artificial stone will be explained with reference to FIG.

The step indicated by the solid line in the figure is one of the specific examples of the method of the present invention, and is hereinafter referred to as the "first step."

Further, the process indicated by the broken line is a normal process that is permissible for obtaining the artificial stone of the present invention, and is hereinafter referred to as the "second process."

First, the slowly cooled and solidified blast furnace slag is collected in step (2), and fluorite is collected in step (2).

Next, both raw materials are crushed to a particle size of 1 mm by an appropriate crusher in the O process.
Dry crush to less than

After that, the blast furnace slag is heat-treated (roasted) in the air (in an oxidizing atmosphere) at a temperature of 500°C or more and below the melting point in step 0, if necessary.
do.

In the F step, raw materials are mixed, and at this time, 8 is added as necessary along with blast furnace slag and fluorite colorant Cr20a and carbon.
102 etc. may be appropriately blended.

In step F, melting is carried out at a temperature approximately 150 to 250°C higher than the melting point of the formulation (usually 1300 to 1450°C).

Since the melting point of the preparation is lowered by the addition of fluorite, this temperature may be relatively lower than that in the case without fluorite.

Next, 0 process of molding and solidification is performed.

In this step, a simple dropping method or a casting method is adopted depending on the shape of the desired artificial stone.

That is, in the former method, a molten material is dropped onto a forming plate (for example, a SUS plate) preheated to 500 to 550° C., and the surface tension of the molten material itself forms the material into a hemispherical shape.

In the latter method, a graphite or steel mold of a predetermined shape is preheated to 500 to 800°C, and the molten material is poured into the mold and solidified.

Thereafter, in the 0 step, the preheating temperature is kept as it is for a predetermined period of time to equalize and remove internal strains generated during cooling and solidification.

The temperature and time for keeping warm may be determined as appropriate depending on the shape and size of the molded product.

Next, in the "first step", reheating treatment of step (2) is performed.

This process is extremely effective, especially when the amount of CaF2 blended is small, and promotes the crystallization of CaF2 in the matrix of the molded product to achieve a predetermined CaF2 crystallization rate (coefficient of 2 or higher).
, and make the artificial stone milky and opaque.

Specifically, this is carried out by reheating at 550 to 800°C for 10 minutes or more.

However, crystallization of CaF2 will proceed slightly even in the slow cooling process described later, so if the amount of CaF2 blended is large, the total CaF2
Even if the crystallization rate is low, the artificial stone as a whole has a certain CaF
2 crystallization ratio may be ensured.

Therefore, when preparing a large amount of CaF2, the artificial stone of the present invention can also be obtained by employing the "second step" in which step (1) is omitted, and by appropriately selecting the conditions for the slow cooling step (2) described later.

However, in any case, the crystallization rate of CaF2 can be increased by carrying out the reheating treatment (2), so if the "first step" is adopted, an even higher quality artificial stone can be obtained.

Finally, by performing slow cooling in step (2), the artificial stone of the present invention can be obtained.

This step is to prevent the molded product from cracking due to thermal strain generated during cooling, and is usually carried out at a rate of 10 C/min or less, although it depends on the shape and size of the molded product.

In particular, the cooling rate between 500°C and 100°C is 10°C.
C/min or more, cracking becomes noticeable.

The artificial stone obtained as a result of the above has a specific gravity of about 2.8,
The hardness is 450-600Hv. Mohs hardness: 4.5~
It is 6 degrees.

These physical property values approximate the specific gravity of jade, which is 2.9 to 3.1, and the Mohs hardness, which is 6 to 6.5.

In particular, the color tone is a beautiful green emulsion (opaque or translucent) that closely resembles that of jade, and it can be put to practical use as a substitute.

Next, a part of the experimental progress until the present invention was completed will be described.

[Relationship between the blending ratio of fluorite (CaF2) and emulsification] Blast furnace slag with the composition shown in Table 1, fluorite with the composition shown in Table 2, and Si0
2 (purity: 99 or higher) as a raw material, artificial stones were manufactured by changing the blending ratio of each component.

However, manufacturing is carried out according to the "second process", roasting conditions of blast furnace slag: 1000 ° C x 5 hours, melting conditions: 1400 ° C, molding / solidification: dropping on SUS plate, heat retention conditions = 550 ° C x 3
0 minutes, slow cooling conditions: 10°C/min or less.

The results are shown in Figure 2. In addition, in FIG. 2, the blending amount in the blast furnace is 50 parts by weight in both cases.

As is clear from the results in Figure 2, there is not much correlation between the amount of Si02 added, which contributes to the vitrification of artificial stone, and emulsification, and the degree of emulsification depends on the amount of fluorite (CaF2) added. According to the figure, it is significantly affected by the amount of C
20 parts by weight in terms of aF2), it becomes semi-turbid and 30 parts by weight (
If more than 25 coefficients (calculated as CaF2) are added, the mixture becomes completely cloudy.

Therefore, in order to obtain the artificial stone of the present invention in the "second step", 25 parts by weight or more of fluorite (calculated as CaF2) should be added to the total raw materials.

[The blending ratio of fluorite (CaF2) and its crystallization rate] The blending ratio of fluorite (CaF2) and the crystallization rate of the artificial stone obtained in the "second step", and the addition of reheating treatment at 800 ° C. for 90 minutes The relationship between the fluorite content ratio and the crystallization rate of CaF2 of the artificial stone obtained in the same manner as above ("first step") was observed, and the results shown in FIG. 3 were obtained.

The crystallization rate of CaF2 was measured by X-ray diffraction method.

As is clear from the results in Figure 3, a large amount of fluorite must be blended in the "2nd step" to ensure the predetermined CaF2 crystallization rate, but compared to the "1st step". A high CaF2 crystallization rate can be obtained even when only a small amount of fluorite is blended.

In order to obtain the jade-like artificial stone of the present invention, the crystallization rate of CaF2 should be about 20 coefficients or less, and in particular, to obtain an artificial stone (jewelry) that is pale and gives a soft and warm feeling to human skin, it is 2 A crystallization ratio of ~15 (emulsified and translucent) is desirable.

For this purpose, the distribution ratio of fluorite is approximately 8 to 25 parts by weight in the first step (approximately 7 to 20 parts by weight in terms of CaF2), and approximately 22 to 35 parts by weight in the second process (18 to 3 parts by weight in terms of CaF2).
(approximately 0) is desirable.

[Relationship between the amount of carbon added and color tone]

Blast furnace slag, fluorite, and Si with the compositions shown in Tables 1 and 2
For the mixture of O2 (purity: 99% or higher) and Cr203 in the proportions shown in Table 3 below, carbon (purity: 99%)
) was added in a range of 0 to 1 inch, and artificial stone was manufactured in the second step.

For this artificial stone, the ratio of the brownish color to the green fabric is shown in relation to the carbon addition ratio as shown in Figure 4.

As can be seen from FIG. 4, a remarkable effect was observed even when 0.1% of carbon was added, and most of the samples exhibited a stable and uniform bright green color when added at 0.2% or more.

Furthermore, when more than one carbon is added, a problem arises in that some of the carbon floats on top of the melt and becomes entangled in the casting during solidification.

From these points of view, the amount of carbon added is preferably 0.2 to 0.8.

Next, examples of the present invention will be shown.

Example Using blast furnace slag and fluorite with the compositions shown in Tables 1 and 2, and using SiO2 as an auxiliary raw material, Cr203 as a coloring agent, and carbon as a color stabilizer, three types of raw materials were prepared according to Table 4. did.

This was treated according to the "first step" in FIG. 1 to obtain artificial stone.

The specific conditions are as follows. Melting process: 1300℃ Molding process: Dropped onto a SUS plate preheated to 500-600℃ Heat retention process: 500℃ x 30 minutes Reheating treatment: 600℃ x 1 hour Slow cooling process: 5℃/min Until 100℃ or less The artificial stone obtained by cooling had the properties and physical properties shown in Table 5 below, and was of extremely high quality as a decorative stone.

Note that sample No. Regarding 2, a reference photo is shown of a product processed in a tight manner.

[Brief explanation of the drawing]

FIG. 1 is a flow sheet illustrating the manufacturing method of the present invention;
The figure is a graph showing the relationship between the blending ratio of fluorite and emulsification, and Figure 3 is a graph showing the relationship between the blending ratio of fluorite and the crystallization rate of CaF2.
FIG. 4 is a graph showing the relationship between the carbon addition ratio and the ratio of brownish color.

Claims (1)

[Claims] 1 Blast furnace slag is the main raw material, plus CaF27-30, C
A jade tone characterized by melting and solidifying a raw material to which R2033% or less and carbon 0.1 to 1% are added, followed by cooling and/or reheat treatment to crystallize CaF2 and color it green. Method of manufacturing artificial stone.