JP2001270738A - Method for producing inorganic fiber material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing an inorganic fiber material having excellent heat resistance and excellent alkali resistance at a low cost. SOLUTION: This method for producing the inorganic fiber material is characterized by mixing coal ash with blast furnace slag, preferably controlling the mixture to a composition comprising 35 to 60 wt.% (as oxide) of SiO2, 15 to 40 wt.% of Al2O3 and 10 to 40 wt.% of CaO and the melting temperature of the mixture to <=1,800 deg.C, and fiberizing the melted product of the mixture.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for easily and inexpensively producing an inorganic fiber material having excellent heat resistance and alkali resistance by using a mixture of coal ash and blast furnace slag as a raw material.

[0002]

2. Description of the Related Art Conventionally, inorganic fiber materials (rock wool) made from blast furnace slag, quartzite, basalt, and the like and melted into fibers have been put into practical use, and have been widely used as incombustible materials and spraying materials for buildings and the like. ing. The blast furnace slag used as a raw material for this rock wool contains silica (SiO), alumina (Al ₂ O ₃ ) and lime (CaO) as main components, but the amount of silica and alumina is smaller than that of lime. Few. For this reason, conventional rock wool using blast furnace slag as a raw material has low heat resistance and alkali resistance, and as a measure against this, there is a problem that a relatively expensive silica raw material must be added.

[0003] On the other hand, the development of an inorganic fiber material using coal ash as a raw material has been attempted, but coal ash has the highest silica content and a considerable amount of alumina.
For this reason, coal ash has a high melting temperature, and it is not easy to melt this and make it fiber. Further, even if it is made into fibers, the number of particles, that is, shots, becomes large, and it is difficult to obtain high-quality fibers, and the production cost becomes extremely high.

[0004]

As described above, an inorganic fiber material using blast furnace slag as a main raw material can be produced at a relatively low cost, but the heat resistance and alkali resistance are insufficient due to the raw material composition. On the other hand, on the other hand, an inorganic fiber material containing coal ash as a main raw material has problems in that the melting temperature is high, the production cost is increased, and the melting furnace is subject to various restrictions.

The present invention solves the above-mentioned problems in the conventional production of inorganic fiber materials, and provides a method for inexpensively producing an inorganic fiber material having excellent heat resistance and alkali resistance from coal ash and blast furnace slag. The purpose is to do. ADVANTAGE OF THE INVENTION According to this invention, the effective utilization of coal ash and blast furnace slag, which are industrial waste, can be promoted.

[0006]

[Means for Solving the Problems] That is, the present invention provides:
(1) A method for producing an inorganic fiber material, comprising mixing coal ash and blast furnace slag to reduce the melting temperature of the mixture to 1800 ° C. or lower to fibrillate the melt. According to the production method of the present invention, (2) coal ash and blast furnace slag are mixed, and the composition of the mixture is converted into Si in terms of oxide weight.
_{O 2: 35~60%, Al 2} O 3: 15~40%, Ca
O: Includes a production method of 10 to 40%.

[0007] By forming a mixture of coal ash and blast furnace slag at an appropriate ratio, the melting temperature becomes lower than that of coal ash alone, and it becomes easier to fibrillate, so that an inorganic fiber material can be produced at a relatively low cost. . Further, by adjusting the content of silica, alumina, and calcium to the above ranges, an inorganic fiber material having excellent heat resistance and alkali resistance can be obtained.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on embodiments. The method for producing an inorganic fiber material according to the present invention, by mixing coal ash and blast furnace slag, compensates for the shortage of the components of both raw materials and lowers the melting temperature as compared with the case of the raw material of coal ash alone, that is, the melting of the mixture Temperature 1800
This is a production method in which the temperature is reduced to not more than ℃ to facilitate fiberization, and the heat resistance and the alkali resistance are further improved as compared with those using blast furnace slag alone as a raw material.

[0009] Coal ash and blast furnace slag are also classified by type.
As a rule, it generally has the chemical composition shown in Table 1. This chemistry
As is clear from the composition, the coal ash is SiO 2_TwoQuantity and A
l_TwoO _ThreeThe amount is large and the CaO amount is small. Therefore the melting temperature
Is high. On the other hand, blast furnace slag has a large CaO content,_Two
Quantity and Al_TwoO_ThreeThe amount is small and therefore this
Inorganic fiber materials tend to decrease heat resistance, alkali resistance, etc.
There is a direction.

[0010]

[Table 1]

According to the present invention, by mixing the coal ash with the blast furnace slag, the insufficient silica in the coal ash is compensated, and the insufficient silica and alumina in the blast furnace slag are compensated. More specifically, the mixture has a SiO ₂ content of 35 to 60% and an Al ₂ O ₃ content of 15 to 4 in terms of oxide weight.
It is preferable to mix so as to have a composition of 0% and CaO: 10 to 40%. Here, it is assumed that the viscosity of the melt and the amount of SiO ₂ is less than 35% is not suitable for fiberizing decreased, whereas, the amount of SiO ₂ is as high as the melting temperature is more than 60%, yet the fiber heat resistance And the alkali resistance decreases. Further, Al ₂ O ₃ amount becomes fiber poor in heat resistance and alkali resistance less than 15% Al ₂ O ₃ amount is too high and the melt temperature is greater than 40%, the melt difficult or costly. Furthermore, Ca
If the O content is less than 10%, the melting temperature becomes too high above the above temperature, making it difficult to melt, or increasing the cost.
On the other hand, if the amount of CaO is more than 40%, the heat resistance and alkali resistance of the fiber are undesirably reduced. The raw material component of the fiber was converted into SiO ₂ : 3 in terms of oxide weight.
_{5~60%, Al 2 O 3:} 15~40%, CaO: 10~
By adjusting the content to the range of 40%, an inorganic fiber material having excellent properties such as heat resistance and alkali resistance can be easily produced at low cost.

[0012] The coal ash and the blast furnace slag are mixed so as to have an appropriate composition. For this mixing, an ordinary powder mixer can be used. Next, this mixture is put into a melting furnace such as an arc furnace and heated to the above-mentioned melting temperature to obtain a melt. After the mixture has melted uniformly, the melt is poured out in a linear fashion. Fiberization can be performed by a method of spinning using a device such as a wind mill or a spinner in which compressed air is blown onto the melt that has flowed out linearly.

[0013]

EXAMPLES The present invention will be specifically described below with reference to examples. Note that the present invention is not limited to these examples.

Example Coal ash having the composition shown in Table 2 and blast furnace slag were mixed at the ratio shown in Table 3 to obtain a raw material. Table 3 also shows the chemical composition of the mixture. This raw material was put into an arc furnace (30 liter internal volume) and melted. After melting sufficiently, the arc furnace was tilted and the melt was poured out linearly, and the wind speed was 200 m / s.
The fibers were formed by blowing air. The sample of this inorganic fiber material was tested for its hot shrink temperature and alkali resistance. Here, the hot shrinkage temperature was determined in accordance with Japanese Industrial Standards (JIS-A-9504), and the alkali resistance was determined from the weight loss after immersing the sample in sodium hydroxide solution (10 normal concentration) for 24 hours. The rate was determined. The results of these tests are shown in Table 4 together with the melting temperature in comparison with test fibers such as rock wool (comparative products 1 and 2).

As is apparent from these results, the inorganic fiber materials obtained by the production method of the present invention are all superior in heat resistance and alkali resistance as compared with the comparative products of commercially available fibers. Specifically, the hot shrink temperature, which is an index indicating the heat resistance, is 820 ° C. or higher in all the examples, whereas the comparative product is 780 ° C. or lower. Further, the dissolution rate with respect to alkali, which is an index of alkali resistance, is 5% or less in all the examples, while the comparative product is 10% or more. Thus, the inorganic fiber material of the present invention is excellent in heat resistance and alkali resistance. Further, since the melting temperature is not so high, the production is easy.

[0016]

[Table 2]

[0017]

[Table 3]

[0018]

[Table 4]

[0019]

According to the production method of the present invention, an inorganic fiber material can be produced at a relatively low cost using a mixture of coal ash and blast furnace slag as a main raw material. Moreover, the produced inorganic fiber material is excellent in heat resistance and alkali resistance, etc., and can be widely used in the construction field such as heat insulating material, heat insulating material, sound absorbing material, cement, and reinforcing material in the concrete field, The application can be expected to be expanded more than conventionally available inorganic fiber materials such as rock wool. In addition, effective utilization of coal ash and blast furnace slag can be promoted.

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Noriaki Morishita 3-8-1, Nishikanda, Chiyoda-ku, Tokyo Inside Taiheiyo Cement Co., Ltd. (72) Inventor Kaichi Noguchi 6-15, Ginza, Chuo-ku, Tokyo No. 1 Inside Power Development Co., Ltd. (72) Yoshitaka Ishikawa, Inventor 6-15-1, Ginza, Chuo-ku, Tokyo Inside Power Supply Co., Ltd. (72) Hiroyuki Nakui 6-15-1, Ginza, Chuo-ku, Tokyo F Term (Reference) 4G062 AA18 BB01 CC04 DA05 DA06 DB04 DB05 DC01 DD01 DE01 DF01 EA01 EB01 EC01 ED01 EE04 EE05 EF01 EG01 FA01 FA10 FB01 FC01 FD01 FE01 FF01 FG01 FH01 FJ01 GA01 GB01 HH03 HH05 HH07 HH09 HH11 HH13 HH15 HH17 HH20 JJ01 JJ03 JJ05 JJ07 JJ10 KK01 KK03 KK05 KK07 KK10 MM01 NN29

Claims (2)

[Claims] 1. A method for producing an inorganic fiber material, comprising mixing coal ash and blast furnace slag to lower the melting temperature of the mixture to 1800 ° C. or lower to fibrillate the molten material. 2. Coal ash and blast furnace slag are mixed to form a mixture having a composition of SiO ₂ : 35 to 60% in terms of oxide weight,
_{Al 2 O 3: 15~40%,} CaO: The method according to claim 1, 10 to 40%.