KR100768384B1 - Coal tar blend and plug for outlet for molten metal - Google Patents

Abstract

The blended coal tar is composed of distilled oil of anhydrous coal tar and soft pitch, and the content of naphthalene is 1.5 mass% or less, and the blended coal tar combines time stability and broad viscosity adaptability without compromising conventional binder properties. It is preferable that the blocking material of the molten metal tapping outlet using the blended coal tar as a binder also has time stability, and the deterioration of the structure and the occurrence of cracking are less likely to occur.

Binder, Oil, Distilled Oil, Coal Tar, Light Pitch

Description

COAL TAR BLEND AND PLUG FOR OUTLET FOR MOLTEN METAL}

TECHNICAL FIELD The present invention relates to a blocking material (hereinafter also referred to as a mad material) of a mixing coal tar and a molten metal tap opening. More specifically, the present invention relates to a blended coal tar having excellent storage stability and easy adjustment of viscosity, a binder comprising the blended coal tar, and further, a mad material using the binder.

Conventionally, anhydrous coal tar obtained by dewatering coal tar is used as a binder of mad materials, such as a blast furnace tapping and an electric furnace tap, or as a binder of various coating materials. Conventional representative mad materials have been produced by adding anhydrous coal tar as a binder to refractory materials made of leadstone, chamotte, alumina and the like, and refractory materials made of carbonaceous materials, silicon carbide, silicon nitride and clay.

In Japanese Unexamined Patent Publication No. Hei 10-324576, it is proposed to use anhydrous coal tar having a large fixed carbon amount as these tar-based binders.

However, when anhydrous coal tar of the said publication is used as a binder of a mad material, the structure of a mad material will become coarse with time, and a problem will generate | occur | produce a crack finally. In addition, it has also been found that the conventional anhydrous coal tar itself deteriorates over time, such as a viscosity increase during storage. Therefore, when it is actually used as a binder, operational irregularities also occur. As described above, the conventional anhydrous coal tar exhibits excellent binder performance at the beginning of the manufacture of the mad material. However, it cannot be concluded that it is an excellent binder because it causes change over time.

In addition, since binders are inherently required to have a viscosity range suitable for the difference in use, it is preferable to have adaptability to the widest viscosity range as possible. However, the above-mentioned anhydrous coal tar has a narrow range of viscosities, and viscosity adjustment is not easy, so the application range is inevitably narrowed.

An object of the present invention is to provide a blended coal tar which is excellent in storage stability which does not change its viscosity or the like even after long-term storage and which is easy to adjust viscosity depending on the use. Another object of the present invention is to provide a mad material and a binder in which the structure is not deteriorated or cracks are generated.

[Initiation of invention]

The above object is achieved by the following invention. That is, this invention is a compounded coal tar which consists of distilled oil of anhydrous coal tar, soft pitch, and naphthalene content rate is 1.5 mass% or less.

Moreover, it is preferable that this compounded coal tar is an oil component of 230-280 degreeC in normal pressure conversion.

Moreover, it is preferable that these compounded coal tars are 100-2400 mPa * s in the viscosity in 60 degreeC.

Moreover, it is preferable that any compounded coal tar mentioned above is 0.1 mass% or less.

Moreover, this application also provides invention of the binder which consists of at least 1 type of compounded coal tar mentioned above.

Moreover, this application also provides invention of the blocking material of the tapping opening of the molten metal which consists of said at least 1 sort (s) of said binder and a refractory material.

Moreover, this invention is a mixture of the soft pitch obtained by tar distillation, and distilled oil obtained by tar distillation, It is also synthetic tar characterized by the naphthalene content being 1.5 mass% or less.

BRIEF DESCRIPTION OF THE DRAWINGS The figure explaining the relationship between the ratio and the viscosity of the 230-280 degreeC distilled oil contained in the mixing coal tar of this invention.

Next, the present invention will be described in more detail with reference to the best mode for carrying out the invention.

MEANS TO SOLVE THE PROBLEM The present inventors first examined the time-lapse deterioration of the mad material which used the conventional anhydrous coal tar as a binder. Conventional anhydrous coal tar is only called dehydrated coal tar obtained by heating and dehydrating coal tar before the fraction of coal tar. Accordingly, it has been found that a significant amount of various volatile components remain in the anhydrous coal tar, and since such volatile matters dissipate over time during storage or use, causing changes in the properties of the anhydrous coal tar itself. As a result, it was found that in the mad material containing the anhydrous coal tar as a binder, the structure becomes coarse with time, and finally cracks occurred. Among these volatile components, naphthalene has a particularly high vapor pressure, sublimation properties, and accounts for about 10% by mass or more of conventional anhydrous coal tar. Therefore, in order to develop a coal tar that has not compromised the characteristics as a conventional binder and combines time stability, the present inventors started from the control of the amount of naphthalene, and in addition to these two characteristics, the present inventors also had the adaptability in a wide viscosity range. The invention of blended coal tar was reached.

The blended coal tar of the present invention is a mixture of soft pitch obtained by distillation of anhydrous coal tar and distilled oil obtained by distillation of anhydrous coal tar, and the content of naphthalene is 1.5% by mass or less.

Here, the soft pitch is a residue remaining after further distillation of anhydrous coal tar from which coal tar is dehydrated. It is preferable that the soft pitch of this invention is a residue which distilled the oil component up to about 280 degreeC. Usually, such soft pitch is a mixture of most complex high boiling point components and free carbon having a softening point of less than 70 ° C and a boiling point of 350 ° C or more. It is preferable that these soft pitches exist in the range of about 35-45 degreeC of a softening point. In addition, the temperature, such as the distillation temperature of this application, was all represented by the value under normal pressure, unless it is specifically determined. Accordingly, the technical scope of the present invention can be known by atmospheric pressure conversion even when applying reduced pressure distillation, pressure distillation, and / or azeotropic distillation.

The distillate oil is an oil obtained by distillation of the above-described anhydrous coal tar, and is preferably an oil component up to about 280 ° C. The naphthalene content of the blended coal tar of the present invention is 1.5% by mass or less, and from the industrial production efficiency, distillate oil of 230 to 280 ° C (referred to as distillate oil, washing oil, absorbent oil, etc.) among the distillate oils is used. It is preferable to use.

As a method of obtaining the blended coal tar of the present invention, as described above, anhydrous coal tar containing hard powders such as naphthalene is distilled off to remove hard powders such as naphthalene, and further distillation is carried out, and the anhydrous coal tar is distilled into distilled oil and soft pitch. After dividing, the method of mixing (synthesizing) the distilled oil and the soft pitch is preferable. At this time, since the naphthalene content is low in both the distilled oil to be used and the soft pitch, the naphthalene content rate of the compounded coal tar obtained becomes 1.5 mass% or less. Thus, since the coal tar is artificially mixed to prepare coal tar, the compound coal tar of the present invention may be called synthetic tar.

However, the method of excluding naphthalene is not limited to the above method. For example, it is also possible to remove naphthalene from the coal tar, the anhydrous coal tar, or the obtained distilled oil until it reaches a specified concentration by means of solvent extraction, sublimation and / or steam distillation. Thereafter, the soft pitch and the distilled oil may be mixed.

Regardless of the method, if the naphthalene content of the blended coal tar is 1.5% by mass or less, the change in the properties over time can be suppressed.

Another feature of the present invention is that the compounded coal tar is obtained by mixing the soft pitch and distilled oil. Therefore, the blended coal tar can be adapted to a wide range of viscosity by changing the mixing ratio of the soft pitch and distilled oil. The preferable viscosity of this compounding coal tar is 100-2400 mPa * s in 60 degreeC. Adjustment of such viscosity is obtained by mixing the said soft pitch (A) and distilled oil (B) in the ratio of A: B = 74-90: 26-10 by mass ratio. If the viscosity at 60 degreeC is 100 mPa * s or more, since adhesiveness and fixed carbon amount as a binder are enough, solvent resistance will not fall. On the other hand, it is because the amount of coal tar required for filling is suppressed in the viscosity of 2400 mPa * s or less at said 60 degreeC, and sufficient solvent resistance is obtained. For reference, the relationship between the content of the distilled oil (230-280 ° C. fraction) in the blended coal tar and the viscosity of the blended coal tar is shown in FIG. 1. As shown, the blended coal tar of the present invention can be arbitrarily and easily changed in accordance with the purpose by changing the content of the distilled oil.

Conventional anhydrous coal tar is not removed from hard components such as naphthalene oil, and mainly contains naphthalene in an amount of 8 to 15% by mass, but phenol also contains about 0.5 to 1.5% by mass. If this phenol is also evaporated, it becomes a problem as an environmental pollutant.

Therefore, the phenol content of the blended coal tar of the present invention is preferably 0.1% by mass or less. The method for making the phenol content in the blended coal tar of the present invention 0.1 mass% or less is the same as the adjustment of the naphthalene content rate described above.

The binder of the present invention comprises at least one of the blended coal tars of the present invention. Although the binder may be the compounded coal tar of the present invention, the binder may be prepared in addition to the binder. Examples of the binder aid include synthetic resins, natural resins, various adhesives, and the like. However, since the binder performance of this invention can fully exhibit binder performance only by the said compounding coal tar, it is usually comprised only by this compounding coal tar.

The binder of the present invention is useful for most applications as a binder or impregnating material such as a mad material, a refractory material, a carbon material, a special carbon material, or various paints. Hereinafter, the use as a binder of a mad material is demonstrated to an example.

The mad material of the present invention comprises the binder and the refractory material of the present invention. As said refractory material, all the conventionally well-known refractory materials for mad materials can be used. For example, the refractory material which consists of refractory raw materials, such as a lead stone, a chamot, and alumina, and carbonaceous material, a silicon carbide, silicon nitride, and clay is mentioned. The mad material of this invention is obtained by mixing the binder of this invention in the ratio of 10-25 mass parts with respect to the said compounding coal tar with respect to 100 mass parts of said refractory materials. Lubrication can be obtained more easily that the usage-amount of this compounding coal tar is more than the said minimum. On the other hand, when the usage-amount of the said blended coal tar is less than the said upper limit, the serviceability improves.

The characteristic of the said mad material is that it is excellent in the storage safety of the mad material obtained similarly to the compounding coal tar of the said invention. That is, even if the above-mentioned mad material of the present invention is stored for a long time, there is no change in the properties of the mad material, for example, the softness (hardness) of the mad material, etc., and since there is little volatile matter, it does not adversely affect the working environment. On the other hand, the mad material using conventional anhydrous coal tar as a binder may become difficult to use because it loses its softness by volatilization of volatile components, such as naphthalene, especially when it is exposed to high ambient temperature in a steel mill or a steel mill. There was a risk of worsening the working environment. Because of such a concern, it is difficult to manufacture a large amount of mad material at one time, but the mad material of the present invention has no such concern, and therefore, there is an advantage that workability is improved.

Next, an Example, a comparative example, and an evaluation example are given as an example and this invention is demonstrated further more concretely. In addition, "part" and "%" in a specification are mass references | standards unless there is particular notice.

[Coal tar distillation]

100 parts of coal tar was heated at about 150 degreeC for 0.5 hour in the dehydration tower, and 97 parts of dehydrated coal tar (anhydrous coal tar) were obtained. 97 parts of this anhydrous coal tar was distilled by atmospheric distillation, and 19 parts of naphthalene oils of 200-250 degreeC of oils, 4 parts of distilled oils of 230-280 degreeC of oils, and 74 parts of residues with a soft pitch were obtained. The properties of the above coal tar, anhydrous coal tar, distilled oil and soft pitch were as shown in Table 1 below.

[Measurement of viscosity]

It measured using the Brookfield B-type rotational viscometer based on the viscosity-measuring method of JISZ 8803 (1991) liquid.

[Measuring Softening Point]

JIS K 2425 (1983) 6. It measured based on the softening point measuring method (circle ball method) of coal tar pitch.

[Measurement of Fixed Carbon]

JIS K 2425 (1983) 9. It measured using the electric furnace based on the fixed carbon content determination method.

[Measurement of moisture]

It measured by the Karl-Fischer method by capacity titration based on JISK0068 (2001).

[Measurement of Content of Naphthalene and Phenol]

It measured by gas chromatography and quantified by the internal standard method.

Example 1 [Compound Coal Tar and Binder]

Distilled oil obtained above and soft pitch were mixed in the ratio of following Table 2, and the 10 kinds of compounded coal tar of this invention were obtained. Their properties are shown in Table 2.

Next, each of 20 g of the blended coal tar 1 (binder 1), the blended coal tar 7 (binder 7) and the blended coal tar 10 (binder 10) was put in a beaker, and left for one week in an atmosphere at 35 ° C. At that time, the naphthalene content and viscosity were measured immediately after manufacture and one week later. The results are shown in Table 3.

Comparative Example 1

The same coal tar used for distillation of coal tar was put in a heating cooker, and it was dehydrated by heating to 235 ° C for 24 hours to prepare anhydrous coal tar (comparative binder) of the comparative example.

Next, in the same manner as in Example 1, 20 g of this anhydrous coal tar was placed in a beaker, and left to stand in an atmosphere at 35 ° C. for one week, and the naphthalene content and viscosity immediately after the production and one week were measured. The results are summarized in Table 3. In addition, this anhydrous coal tar is corresponded to the anhydrous coal tar of Unexamined-Japanese-Patent No. 10-324576, the viscosity in 60 degreeC is 280 mPa * s, the fixed carbon is 32%, and moisture is 0.1%. Naphthalene content rate was 10.9%.

<Example 2> [Mad material]

To 100 parts of powdered refractory material consisting of alumina, silica, silicon carbide, silicon nitride, carbon and the like, 18 parts of the blended coal tar 1 (binder 1) of Example 1 were added and mixed well to prepare a mad material 1 of the present invention. Similarly, the mad material 7 and the mad material 10 of the present invention were prepared using compounded coal tar 7 (binder 7) and compounded coal tar 10 (binder 10). The composition of each mad material is shown in Table 4.

Comparative Example 2

The mad material of the comparative example was prepared like Example 2 using the anhydrous coal tar of the comparative example 1 (the binder of a comparative example). The composition is written together in Table 4.

Next, 1 kg of the mad materials 1, 7, 10 and 1 kg of the mad materials of the comparative example were left to stand at 35 ° C for one week, and the hardness (softness) of each of the mad materials immediately after the production and one week after was measured. The hardness was measured by using a needle immersion hardness tester (Crust hardness tester manufactured by Daiki Rika Kogyo Co., Ltd.) after keeping each mad material at 70 ° C. for 5 hours. The results are summarized in Table 4.

As can be seen from Table 1 and Table 2, the blended coal tar of the present invention has extremely low volatility such as naphthalene and phenol, which is also an environmental pollutant, compared to conventional coal anhydride. In addition, since the blending ratio of the soft pitch and the distilled oil is arbitrarily changed, the viscosity can be easily adjusted and can be used for a wide range of viscosities. In addition, as is clear from Table 3, even if the compounded coal tar and the binder of the present invention are stored for a long time, the viscosity change is small and the storage stability is excellent. Moreover, the mad material using the binder of this invention which consists of said compounded coal tar also has time stability. In the results of Table 4, the mad material of the comparative example equivalent to the conventional product has a hardness increase rate of 90%, whereas that of the mad material of the present invention is only about 30%. Therefore, in the mad material of the present invention, the deterioration of the structure and the occurrence of cracking are less likely to occur.

According to the present invention, it is possible to provide a compounded coal tar having excellent storage stability and easy viscosity adjustment depending on the application and various binders comprising the compounded coal tar. In addition, according to the present invention, it is possible to provide a mad material which is excellent in storage stability and hardly deteriorates in structure or cracks.

Claims (7)

A blended coal tar comprising distilled oil of anhydrous coal tar and a soft pitch, and having a naphthalene content of 1.5% by mass or less. The method of claim 1, The blended coal tar, characterized in that the distillate oil is an oil of 230 to 280 ℃ in terms of atmospheric pressure. The method of claim 1, The viscosity in 60 degreeC is 100-2400 mPa * s, The compounded coal tar characterized by the above-mentioned. The method of claim 1, Compounded coal tar characterized by a phenol content of 0.1% by mass or less. A binder comprising the compounded coal tar according to any one of claims 1 to 4. It consists of the binder of Claim 5, and a fireproof material, The blocking material of the tapping outlet of molten metal characterized by the above-mentioned. A mixture of a soft pitch obtained by tar distillation and distilled oil obtained by tar distillation, wherein the naphthalene content is 1.5% by mass or less.

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