阅读说明：本技术 抗辐射性无机材料及其纤维 (Radiation-resistant inorganic material and fiber thereof ) 是由 深泽裕 于 2020-04-22 设计创作，主要内容包括：本发明提供一种抗辐射性优异,且熔融纺丝性优异的无机材料。在包含SiO-(2)、Al-(2)O-(3)、CaO和Fe-(2)O-(3)成分的无机材料中,通过其无机材料中的上述成分的氧化物换算下的质量百分含量为如下,i)将SiO-(2)和Al-(2)O-(3)的总计含量设为40质量％以上且70质量％以下,ii)将Al-(2)O-(3)/(SiO-(2)+Al-(2)O-(3))(质量比)设为0.15～0.40的范围,将iii)Fe-(2)O-(3)的含量设为16质量％以上且25质量％以下,iv)将CaO的含量设为5～30质量％,从而能够设为熔融纺丝性优异,且抗辐射性优异的无机材料。(The invention provides an inorganic material having excellent radiation resistance and excellent melt spinning property. In the presence of SiO 2 、Al 2 O 3 CaO and Fe 2 O 3 In the inorganic material of component (b), oxygen of the above-mentioned component in the inorganic material is passed throughThe mass percentage content in terms of compounds is as follows, i) SiO 2 And Al 2 O 3 Is 40 to 70 mass%, ii) Al 2 O 3 /(SiO 2 +Al 2 O 3 ) (mass ratio) 0.15-0.40, iii) Fe 2 O 3 Iv) 5 to 30% by mass of CaO, thereby making it possible to obtain an inorganic material having excellent melt spinnability and excellent radiation resistance.)

1. An inorganic material with radiation resistance, which contains SiO₂、Al₂O₃CaO and Fe₂O₃The components of the components are mixed and stirred,

wherein the inorganic material has the following mass percentage content in terms of oxides of the above components,

i)SiO₂and Al₂O₃The total content of (B) is 40 to 70 mass%,

ii)Al₂O₃/(SiO₂+Al₂O₃) (mass ratio) is in the range of 0.15 to 0.40,

iii)Fe₂O₃is 16 to 25 mass%,

iv) the content of CaO is 5 to 30 mass%.

2. The inorganic material according to claim 1, wherein it is used for a radiation irradiated portion.

3. A fiber comprised of the inorganic material of claim 1 or 2.

4. A fiber reinforced composite reinforced with the fiber of claim 3.

5. The fiber-reinforced composite of claim 4, wherein it is a fiber-reinforced resin.

6. The fiber-reinforced composite according to claim 4, wherein it is a fiber-reinforced cement.

7. A method for producing a radiation-resistant inorganic fiber, comprising melt-spinning a mixture of a silica source, an alumina source, a calcium oxide source and an iron oxide source,

wherein SiO in the mixture₂、Al₂O₃CaO and Fe₂O₃The content of the oxide (B) is as follows by mass percentage,

i)SiO₂and Al₂O₃The total content of (B) is 40 to 70 mass%,

ii)Al₂O₃/(SiO₂+Al₂O₃) (mass ratio) is in the range of 0.15 to 0.40,

iii)Fe₂O₃is 16 to 25 mass%,

iv) the content of CaO is 5 to 30 mass%.

8. The method for producing an inorganic fiber according to claim 7, wherein the method is used for irradiating the irradiated portion.

9. The method for producing an inorganic fiber according to claim 7 or 8, wherein fly ash is used as the silica source or the alumina source.

10. The method for producing inorganic fibers according to claim 9, wherein the iron oxide source is copper slag.

11. The method for producing inorganic fibers according to claim 10, wherein the calcium oxide source is steel slag.

12. The method for producing an inorganic fiber according to claim 7 or 8, wherein the silica source or the alumina source is basalt or andesite.

13. The method for producing an inorganic material according to claim 12, wherein the iron oxide source is copper slag.

14. The method for producing an inorganic material according to claim 13, wherein the calcium oxide source is steel slag.

15. Use of an inorganic material comprising Si in a radiation irradiated partO₂、Al₂O₃CaO and Fe₂O₃The components of the components are mixed and stirred,

the inorganic material contains the following components in percentage by mass in terms of oxides,

i)SiO₂and Al₂O₃The total content of (B) is 40 to 70 mass%,

ii)Al₂O₃/(SiO₂+Al₂O₃) (mass ratio) is in the range of 0.15 to 0.40,

iii)Fe₂O₃is 16 to 25 mass%,

iv) the content of CaO is 5 to 30 mass%.

16. Use of the inorganic material according to claim 15 in irradiating an irradiated portion,

the radiation irradiated portion is any one of,

a) nuclear reactor building, nuclear reactor storage vessel, nuclear reactor plant piping, and robot for treating deactivated nuclear reactor

b) Space base building, space station, artificial satellite, planet detection satellite and space suit

c) A medical device utilizing a particle beam.

17. A method of suppressing radiation deterioration of a fiber-reinforced composite material of a radiation-irradiated portion, in the method of suppressing radiation deterioration of a fiber-reinforced composite material constituting the radiation-irradiated portion,

providing the fiber to contain SiO₂、Al₂O₃CaO and Fe₂O₃The inorganic fibers of the component (a),

the inorganic material has the following mass percentage content in terms of oxides of the above components,

i) mixing SiO₂And Al₂O₃The total content of (B) is 40 to 70 mass%,

ii) adding Al₂O₃/(SiO₂+Al₂O₃) (mass ratio) is set to be in the range of 0.15 to 0.40,

iii) adding Fe₂O₃The content of (B) is 16 to 25 mass%,

iv) setting the content of CaO to 5-30 mass%.

Technical Field

The present invention relates to a novel inorganic material having excellent radiation resistance and a fiber thereof. More specifically, the present invention relates to a radiation-resistant inorganic material having excellent melt spinnability and a fiber thereof.

Background

Due to the major earthquake attacking east japan in 3 months in 2011 (major earthquake in east japan), the nuclear power plant is destroyed, and a large amount of manpower and resources have to be invested in the disposal of the inactivated nuclear reactor and the radioactive waste.

On the other hand, after a major earthquake in east japan, many nuclear power plants are stopped due to increased safety regulations for nuclear reactors, and the rate of thermal power generation is increasing. Coal is generally used as a fuel for thermal power generation, but in this case, a large amount of fly ash is generated. In the past, fly ash was treated as waste, but in recent years, with the progress of use as a concrete admixture, the amount of waste is decreasing as a result. However, most of the utilization thereof depends on the cement field, and there is a fear that if the cement demand is stagnated, the fly ash to be disposed of is increased again. Therefore, the development of new applications of fly ash is a problem to be solved urgently. The composition of fly ash varies depending on the raw coal and the place of production (power plant, country).

As an example of the utilization of fly ash at a high level, for example, Japanese patent laid-open No. Hei 6-316815 (hereinafter, patent document 1) discloses a fly ash fiber characterized by containing 20 to 40% of Al₂O₃35 to 50% of SiO₂15-35% of CaO, 3-12% of Fe₂O₃And 2-5% of MgO. The same document describes "Fe contained in fly ash fibers₂O₃The content is 3-12%. It is desirable that the smaller this content, the better. And, with Fe₂O₃The increase in the content is not preferable because the degree of coloring of the fly ash fiber increases. From this, it is found that 12% or more of Fe is contained₂O₃The content, which has many problems, should be avoided. "(same document, [0054 ]]Segment).

In addition to the fly ash fiber, for example, with respect to the mineral fiber, Japanese patent publication 2018-531204 (hereinafter, patent document 2) discloses a mineral fiber containing Al₂O₃、SiO₂CaO, MgO and Fe₂O₃Component (b), the mineral fibers being characterized by Fe₂O₃The content is 5-15%. In the same document, "an increase in iron content tends to color mineral fibers, and particularly, it is said that mineral fibers are not preferable for use in maintaining a visible state" (the same document, [0005 ] is said]Segment).

Both patent documents 1 and 2 use Al₂O₃、SiO₂CaO and Fe₂O₃Are connected in this respect to the essential constituents and Fe is discussed₂O₃The content of (b) is required to be limited to a predetermined amount or less (12% or less in patent document 1 and 15% or less in patent document 2).

Further, Japanese patent laid-open No. Sho 60-231440 (hereinafter, patent document 3) and Japanese patent laid-open No. Hei 10-167754 (hereinafter, patent document 4) disclose a glass or a vitrified material, which is characterized in that Al is used₂O₃、SiO₂CaO and Fe₂O₃Is an essential component, and the content of each oxide component is within a specific range.

In addition, in the Materials Research Bulletin]36(2001)1513-1520 (non-patent document 2) describes iron oxide (Fe) using goethite (FeOOH) industrial waste as a sample₂O₃) The relationship between content and magnetic properties.

In addition, patent documents 1, 2, 3, 4 and non-patent document 2 do not mention anything about radiation resistance.

However, as previously mentioned, radiation resistant materials are essential for the treatment of nuclear power plants in disaster and the treatment of radiation contaminated waste and radiation contaminated soil and radiation waste treatment.

As a radiation resistant material, basalt fiber using basalt (basalt) as a raw material has attracted attention, but as far as the inventors know, no document has been found which discusses the relationship between the composition and the radiation resistance. In addition, the kind and composition of basalt (table 1) are described in the following table of science annual tables (hereinafter, non-patent document 1).

[ Table 1]

< species and composition sources of basalt: science year table >

Composition (I)	Alkaline basalt	Continental overflow basalt	Basalt on ocean islands	Deep sea basalt	Island arc basalt
						SiO2	45.4	50.01	50.51	50.68	51.9
Al2O3	14.7	17.08	13.45	15.6	16
						Fe2O3	4.1	-	1.78	-	-
FeO	9.2	10.01	9.59	9.85	9.56
						CaO	10.5	11.01	11.18	11.44	11.8
MnO	-	0.14	0.17	-	0.17
						MgO	7.8	7.84	7.41	7.69	6.77
TiO2	3	1	2.63	1.49	0.8
						Na2O	3	2.44	2.28	2.66	2.42
K2O	1	0.27	0.49	0.17	0.44
						P2O5	-	0.19	0.28	0.12	0.11
Total of	98.7	99.99	99.77	99.7	100

Furthermore, a review on basalt fiber (International Journal of Textile Science) is reported]2012,1(4): 19-28, non-patent document 3), SiO is described as a typical composition of basalt₂：52.8％、Al₂O₃：17.5％、Fe₂O₃：10.3％、CaO：8.59％。

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. Hei 6-316815

Patent document 2: japanese patent disclosure 2018-5-531204

Patent document 3: japanese patent laid-open No. Sho 60-231440

Patent document 4: japanese patent laid-open publication No. Hei 10-167754

Non-patent document

Non-patent document 1: 2019 year edition of science chronology (national astronomical table)

Non-patent document 2: materials Research Bulletin [ Materials Research Bulletin ]36(2001)1513-

Non-patent document 3: international Journal of Textile Science 2012, 1 (4): 19-28

Disclosure of Invention

Technical problem to be solved by the invention

As above, for containing SiO as the main component₂、Al₂O₃And Fe₂O₃The inorganic material of (2) has not been found to be within the knowledge of the present inventors for the purpose of improving the radiation resistance.

Therefore, the present inventors have made an effort to improve the SiO contained as a main component for the purpose of improving the radiation resistance₂、Al₂O₃And Fe₂O₃The inorganic material of (2) has excellent radiation resistance, particularly excellent melt spinnabilityA radiation resistant inorganic material.

Means for solving the technical problem

As a result, it was found that₂And Al₂O₃Among the main constituent inorganic materials, SiO₂And Al₂O₃In a specific range, Al₂O₃In SiO₂And Al₂O₃The ratio of (A) to (B) is within a specific range, and further contains a specific amount of Fe₂O₃And CaO, which is excellent in radiation resistance and melt spinning property, and as a result, a material suitable for the radiation-irradiated portion is completed.

Namely, an inorganic material of the present invention, which contains SiO₂、Al₂O₃CaO and Fe₂O₃Wherein the inorganic material comprises the following components in percentage by mass in terms of oxides,

i)SiO₂with Al₂O₃The total content of (B) is 40 to 70 mass%,

ii)Al₂O₃in SiO₂And Al₂O₃The ratio (mass ratio) of the total amount of (A) is in the range of 0.15 to 0.40,

iii)Fe₂O₃is 16 to 25 mass%,

iv) the content of CaO is 5 mass% or more and 30 mass% or less, and the inorganic material is suitably used for the radiation-irradiated portion.

Hereinafter, the above i) to iv) may be simply referred to as "4 elements of the present invention relating to the composition".

Specific examples of the irradiated portion using the inorganic material of the present invention will be described later.

In the present invention, no substantial difference was observed between the component ratio in the preparation mixture of each raw material and the component ratio in the material after melting the mixture. Therefore, the component ratio in the formulation mixture can be used as the material component ratio.

The inorganic material of the present invention contains SiO as a component₂、Al₂O₃、Fe₂O₃And CaO in such a manner that the ratio of the raw materials is maintained in the above range, and the raw materials are melted after adjusting the preparation ratio to obtain the final inorganic material.

As described below, when the raw materials are formulated so as to be kept within the above range, the raw materials are melted at a temperature that is not excessively high, and the melt has an appropriate viscosity, so that the melt spinning property is excellent. The obtained inorganic material is excellent in radiation resistance.

SiO in the inorganic Material of the present invention₂And Al₂O₃The total content of (a) is 40 to 70 mass%. In the following description, SiO may be used₂Simply referred to as S component, SiO₂Is expressed as [ S ]]. Similarly, Al may be added₂O₃Abbreviated as component A, will be Al₂O₃Is represented by [ A ]]. If [ S ]]And [ A ]]When the total of (a) and (b) is outside the above range, that is, less than 40% by mass or more than 70% by mass, the melt temperature of the material becomes high, the viscosity of the melt becomes high, or conversely, the melt viscosity becomes too low, resulting in poor melt spinnability.

In the inorganic material of the present invention, Al₂O₃In SiO₂And Al₂O₃The ratio of (A) to the total amount of (B) ([ A ]]/([A]+[S]) (mass ratio) is required to be in the range of 0.15 to 0.40. In any case where the element is out of the above range, i.e., less than 0.15 or more than 0.40, the melt spinnability of the material is poor.

In the inorganic material of the present invention, Fe₂O₃The content of (b) is required to be 16 mass% or more and 25 mass% or less. When Fe₂O₃When the content of (b) is less than 16% by mass, the radiation resistance of the material is poor. On the other hand, when the content exceeds 25% by mass, the viscosity of the melt is too low to form a yarn. Hereinafter, Fe may be used₂O₃Component F, will be referred to as Fe₂O₃Is represented by [ F ]]。

In the inorganic material of the present invention, the content of CaO is preferably 5 mass% or more and 30 mass% or less. When the content of CaO is less than 5 mass%, the melting start temperature of the material becomes high, which is not preferable from the viewpoint of energy saving. The content of CaO is preferably 10 mass% or more. On the other hand, if the content exceeds 30 mass%, the viscosity of the melt is too low, and it is difficult to form a yarn. Hereinafter, CaO may be abbreviated as component C, and the content of CaO is represented as [ C ].

When the inorganic material of the present invention is obtained, only SiO is used₂、Al₂O₃、Fe₂O₃And CaO in the above range, the raw materials are not limited.

Thus, although SiO can be formulated₂、Al₂O₃、Fe₂O₃And CaO as the starting materials, but it is preferable to prepare SiO-rich compounds from the viewpoint of the cost of the raw materials₂Silicon dioxide source of (1), enriched with Al₂O₃Is rich in Fe₂O₃The iron oxide source and the calcium oxide source rich in CaO are used as initial raw materials.

Examples of the silica source include amorphous silica, quartz sand, fumed silica, and volcanic ash, but are not limited thereto.

Examples of the alumina source include, but are not limited to, alumina and other mullite ores.

Examples of the alumina source (silica-alumina source) that can be used as the silica source include kaolinite, montmorillonite, feldspar, and zeolite, but are not limited thereto.

Examples of the iron oxide source include, but are not limited to, iron oxide, iron hydroxide, and iron ore.

Examples of the calcium oxide source include, but are not limited to, calcium carbonate, calcite, dolomite, and other ores.

Furthermore, thermal power generation waste and metallurgical waste can be effectively used as one of a silica source, an alumina source, an iron oxide source, and a calcium oxide source.

As the thermal power generation waste material, fly ash and clinker ash can be used. Fly ash and clinkerThe material ash is rich in SiO₂、Al₂O₃And thus are suitable as silica-alumina sources. Of course, the Fe in fly ash and clinker ash₂O₃The content is small, and therefore it is difficult to obtain the inorganic material of the present invention only by these. However, the inorganic material of the present invention can be obtained at low cost by additionally preparing an appropriate amount of an iron oxide source. In addition, since a gasified Slag (CGS) produced from a waste material of an Integrated Coal Gasification Combined Cycle (IGCC) has substantially the same chemical composition as that of fly ash, it can be used as a silica-alumina source. The gasified slag is granular, and therefore, has an advantage of excellent operability.

As the previously mentioned metallurgical wastes, steel slag and copper slag can be cited.

The steel slag can be used as a calcium oxide source because of its high CaO content. The steel slag comprises blast furnace slag, converter slag and reducing slag.

Copper slag due to Fe₂O₃High in content and thus can be used as an iron oxide source.

Therefore, fly ash, clinker ash or gasified slag can be suitably used as the silica-alumina source, copper slag can be suitably used as the iron oxide source, and steel slag can be suitably used as the calcium oxide source. In a preferred embodiment, a majority of the silica-alumina source, iron oxide source, and calcium oxide source may be provided from industrial waste. Furthermore, volcanic rocks typified by basalt and andesite can also be used as the silica-alumina source.

The inorganic material of the present invention does not exclude mixing of inevitable impurities contained in the raw materials. Examples of such impurities include MgO and Na₂O、K₂O、TiO₂、CrO₂And the like.

Since the inorganic material of the present invention is rich in amorphous, the fiber subjected to melt spinning is hardly reduced in strength by peeling at the interface between the crystalline phase and the amorphous phase, and a high-strength fiber can be obtained.

Here, the degree of amorphization, which is a measure of amorphousness, is calculated by the following equation (1) using X-ray diffraction (XRD) spectroscopy.

Amorphization (%) - [ Ia/(Ic + Ia) ]. times.100 (1)

(in the formula (1), Ic is the sum of integrated values of the scattering intensities of the crystal peaks when the inorganic material is subjected to X-ray diffraction analysis, and Ia is the sum of integrated values of the non-crystalline halo scattering intensities).

The degree of amorphization of the inorganic material of the present invention is usually 90% or more based on the composition. The degree of amorphization may be 95% or more in the case of a high degree of amorphization, and the fiber may substantially consist of only an amorphous phase in the highest case. Here, the phrase "consisting essentially of only an amorphous phase" means that only an amorphous halo is observed in an X-ray diffraction spectrum, and a crystalline phase peak is not observed.

The radiation resistance of the material made of the inorganic material of the present invention can be found by comparing the vickers hardness of the material before and after irradiation with radiation. Further, the radiation resistance can be evaluated by comparing the tensile strength before and after irradiation with radiation and the porosity of the material. The porosity in the material can be measured by positron annihilation.

Effects of the invention

For the SiO-containing₂、Al₂O₃CaO and Fe₂O₃The conventional inorganic material of the component (B), the inorganic material of the present invention is formed of SiO₂And Al₂O₃Total of (1), Al₂O₃In SiO₂And Al₂O₃The total of (1), Fe₂O₃The content of (b) and the content of CaO are within specific ranges, and thus the yarn is excellent in radiation resistance and melt spinnability.

Drawings

Fig. 1 is a schematic explanatory view showing the outline of the melt spinnability evaluation test of the inorganic material of the present invention together with an enlarged view of a melt spun fiber.

Fig. 2 shows XRD spectra before and after irradiation of the melt-spun fiber of the inorganic material of example 1.

Fig. 3 is a graph showing the relationship between the iron oxide content and the radiation resistance in the inorganic material.

Fig. 4 is a diagram showing several examples of XRD spectra of the inorganic fibers of examples and comparative examples.

Fig. 5 is a diagram showing several examples of DTA curves based on differential thermal analysis of the inorganic fibers of examples and comparative examples.

Detailed Description

The contents of the present invention will be specifically described below by way of test examples.

In the following test examples (examples and comparative examples), the following materials were used as a silica source, an alumina source, an iron oxide source, and a calcium oxide source.

< silica Source >

Silica: the reagent (in tables 6 to 9, SiO)₂(reagent)

< alumina source >

Alumina: the reagent (in tables 6 to 9, Al is shown below)₂O₃(reagent)

< iron oxide Source >

Iron (III) oxide: the reagent (in tables 6 to 9, Fe is shown below)₂O₃(reagent)

Copper slag: copper dross (shown by FA (10) in Table 3 below) produced in a copper smelting plant in Japan

< calcium oxide Source >

Calcium oxide: reagent (CaO (reagent) in tables 6 to 9 below)

Blast furnace slag: blast furnace slag produced in iron and Steel works in Japan (shown as FA (13) in Table 3 below)

Reducing slag: reducing slag produced in iron and Steel works in Japan (shown as FA (14) in Table 3 below)

< silica-alumina source >

Fly ash: 12 samples (in tables 2 and 3 described below, represented by FA (1) to FA (9), FA (12)) discharged from a Japanese thermal power plant

Gasification slag: samples discharged from an integrated coal gasification combined cycle power plant in Japan (shown as FA (11) in Table 3 below)

Volcanic rock: basalt series rocks having a high iron oxide content (represented as BA (1) and BA (2) in Table 4 below) selected exclusively from autumn and Fujing counties

The compositions of FA (1) to FA (14), BA (1) and BA (2) are shown in tables 2, 3 and 4. In addition, the composition analysis was based on a fluorescent X-ray analysis method.

[ Table 2]

Composition of fly ash, unit: mass% >)

Composition (I)	FA(1)	FA(2)	FA(3)	FA(4)	FA(5)	FA(6)
							Fe2O3[F]	10	5	5	9	10	14
SiO2[S]	53	61	57	72	51	59
							Al2O3[A]	13	25	18	11	18	25
CaO[C]	17	0	3	3	12	1
							Others	7	9	17	5	9	1

[ Table 3]

Composition of coal ash and slag charge, unit: mass% >)

Composition (I)	FA(7)	FA(8)	FA(9)	FA(10)	FA(11)	FA(12)	FA(13)	FA(14)
									Fe2O3[F]	9	13	15	55	9	1	0	1
SiO2[S]	62	60	59	35	54	73	34	19
									Al2O3[A]	18	15	15	5	11	22	13	17
CaO[C]	3	5	3	2	17	0	42	55
									Others	8	7	8	3	9	4	11	8
Remarks for note				Copper slag	Gasification of slag		Blast furnace slag	Reducing slag

[ Table 4]

Composition of volcanic rock, unit: mass% >)

Composition (I)	BA(1)	BA(2)
			Fe2O3[F]	19	18
SiO2[S]	46	25
			Al2O3[A]	11	10
CaO[C]	17	3
			Others	7	44

< preparation of powdery raw Material >

In the following test examples, silica, alumina source, iron oxide source and calcium oxide source were each finely pulverized to prepare SiO₂、Al₂O₃、Fe₂O₃And CaO in a specified proportion for testing.

< evaluation of melt spinning Property >

Further, the evaluation of the melt-spinnability of the material was dependent on a melt-spinning test using an electric furnace. The outline of the test is shown in FIG. 1. In FIG. 1, the electric furnace (1) had a height (H) of 60cm, an outer diameter (D) of 50cm, and an opening (4) having a diameter (D) of 10cm at the center thereof. On the other hand, at the inner diameter30g of materials are filled in a carbon particle heating tube (2) with the length of 2.1cm and the length of 10 cm. In addition, a hole with the diameter of 2mm is arranged at the center of the bottom of the carbon particle heating tube (2). In the melting test, the carbon particle heating tube (2) is held at a predetermined position in an opening (4) of an electric furnace by a hanger rod (3).

When the material is melted by heating, the material flows down from the bottom of the carbon particle heating tube due to its own weight and is solidified by contacting with the outside air to form a fiber.

The electric furnace was heated according to a predetermined temperature-raising program, and the maximum reached temperature in the furnace was set to 1350 ℃. At this time, it was confirmed in advance that the temperature inside the carbon particle heating tube (melt) followed by a temperature approximately 50 ℃ lower than the temperature inside the furnace.

In the present invention, as an evaluation index of the melt spinning property, a case where the melt flows and falls down to form a yarn before the temperature in the furnace reaches 1350 ℃, that is, the melting temperature of the sample is 1300 ℃ or lower, and the melt has melt viscosity suitable for forming a yarn is set as an allowable level. The melting operation of the sample is roughly classified into groups shown in the following a to D.

< evaluation rating >

A: forming a yarn.

B: the melted and softened sample flowed out from the bottom of the carbon particle heat-generating tube, but the viscosity was high, and the sample did not fall down by its own weight alone, and no yarn was formed.

C: since the sample did not start melting or the melting was insufficient, nothing flowed out from the carbon particle heat generating tube.

D: the sample melted, but the melt viscosity was too low to drop as droplets, and yarn formation was impossible.

< Heat resistance test >

The inorganic fibers made of the material of the present invention are also excellent in heat resistance. Differential Thermal Analysis (DTA) was performed to evaluate heat resistance.

[ preliminary test ]

After properly preparing silicon dioxide, an alumina source, an iron oxide source and a calcium oxide source, SiO is prepared₂、Al₂O₃、Fe₂O₃And 4 samples with different CaO content for melt spinning test. Samples 3 and 4 satisfy all the elements of the present invention described above, but samples 1 and 2 lack Fe₂O₃Element iii) of content (table 5).

Either sample showed good melt spinnability. The obtained fiber sample was subjected to a radiation irradiation test under a gamma ray of 50kGy using cobalt 60 as a radiation source, and the tensile strength before and after irradiation was measured to determine the retention thereof.

The results are shown in Table 5. FIG. 3 is a graph showing iron oxide (Fe) in a sample₂O₃) Graph of the relationship between the content and the fiber strength retention after irradiation with radiation. It is thus understood that iron oxide (Fe) in the material₂O₃) When the content of (b) is 15% or more, the retention of tensile strength after irradiation is significantly improved.

[ Table 5]

[ example 1]

30 parts by mass of FA (1) and 70 parts by mass of BA (1) were prepared. The composition of this sample was the same as that of sample 3 used in the above-described preliminary test. The composition ratio of the sample is [ S ] + [ A ]: 60%, [ A ]/([ S ] + [ A ]): 0.20, [ F ]: 16 mass%, [ C ]: 17% by mass (Table 6).

As a result of the melt spinning test, it was found that an ultrafine fiber (mineral fiber) having a diameter of 50 μm or less was obtained within 5 hours after the temperature in the furnace reached 1350 ℃. The obtained fiber has a strength that is not easily broken even if pulled by hand. The fiber sample was irradiated under the following conditions.

< high radiation irradiation test >

The fiber sample was subjected to an ultra-high dose radiation exposure test using a nuclear reactor (thermal neutron reactor, BR2) installed in belgium moir research center. The gamma ray exposure was 5.85 GGy. This dose is comparable to the radiation dose that would normally be released by high levels of radiant waste in about 1000 years.

The fiber sample after irradiation was subjected to the following XRD analysis and vickers hardness test together with the fiber sample without irradiation.

< XRD analysis >

The XRD spectra of the fiber samples before and after irradiation with radiation are shown in fig. 2 (before irradiation: left, after irradiation: right, and the vertical axis represents diffraction intensity in arbitrary units (a.u)). In addition, since the sample irradiated with the radiation may emit the radiation, only in this case, a dome-shaped shield for restricting the opening is provided on the sample support base. This is why the range of the measured incidence angle of the spectral data (fig. 2 right panel) of the sample after irradiation is narrowed.

Only an amorphous halo was observed in the XRD spectra of the fiber sample before irradiation and the fiber sample after irradiation, and no crystalline phase peak was observed. That is, it was found that the amorphous state can be maintained even by irradiation with radiation since the amorphous phase is substantially composed only of the amorphous phase before and after irradiation with radiation.

< Vickers hardness test >

The vickers hardness test was performed on the fiber sample before irradiation and the fiber sample after irradiation.

The test instruments used were Reichert-Jung Microduromat 4000E and Leica Telatom 3 optical microscopes. Considering that the width of the fiber sample was about 20 μm, the force applied to the sample surface was set to 10gF (0.098N).

As a result of measurement of 17 points of each sample before and after irradiation with radiation, 723. + -. 24kgF/mm was obtained before irradiation with radiation²647 +/-19 kgF/mm after radiation irradiation². The vickers hardness retention after irradiation was 89%, and it can be said that the value is very high in consideration of the gamma ray irradiation amount being 5.85 GGy. As described above, the material is very excellent in radiation resistance. For comparison, the values of retention (89%) based on the present test are plotted in fig. 3 shown previously. It is to be noted that, although the determination method of the strength retention rate is different, the retention rate close to 90% is maintained as the strength retention rate even when the sample having the iron oxide content of 16% is irradiated with the ultra-high dose of about 10 ten thousand times as much as the preliminary test described previously.

[ example 2]

The samples were prepared at the raw material formulation ratios shown in example 2 in table 6. The composition ratio of the sample is [ S ] + [ A ]: 60%, [ A ]/([ S ] + [ A ]): 0.25, [ F ]: 19 mass%, [ C ]: 13% by mass (Table 6).

As a result of the melt spinning test, the sample melted and dropped within 5 hours after the temperature in the furnace reached 1350 ℃ to obtain ultrafine fibers (mineral fibers) having a diameter of 50 μm or less.

The obtained fiber sample substantially consists of only the amorphous phase and is not easily broken even if pulled by hand, as in example 1. Further, the non-crystallinity was maintained even by irradiation with radiation, and the vickers hardness retention ratio was at the same level as in example 1. As described above, the material is very excellent in radiation resistance.

[ example 3]

The samples were prepared at the raw material formulation ratios shown in example 3 in table 6. The composition ratio of the sample is [ S ] + [ A ]: 56%, [ A ]/([ S ] + [ A ]): 0.20, [ F ]: 18 mass%, [ C ]: 25% by mass (Table 6).

The results of the melt spinning test showed that the sample melted and dropped within 5 hours after the temperature in the furnace reached 1350 ℃ to obtain ultrafine fibers (mineral fibers) having a diameter of 50 μm or less.

The obtained fiber sample substantially consists of only the amorphous phase and is not easily broken even if pulled by hand, as in example 1. The non-crystallinity can be maintained even by irradiation with radiation, and the vickers hardness retention ratio is at the same level as in example 1. As described above, the material is very excellent in radiation resistance.

Comparative examples 1 to 8

The samples were prepared according to the raw material preparation ratios shown in comparative examples 1 to 8 in Table 6. Both lack any of the 4 elements that make up the invention.

The results showed that no fiberization occurred in any of the samples within 5 hours after the furnace temperature reached 1350 ℃ (table 6).

[ Table 6]

[ examples 4 to 11]

As the silica-alumina source, fly ash FA (7) was selected, and a reagent SiO was additionally prepared as required so as to satisfy "4 elements of the present invention relating to the composition₂(S)、Al₂O₃(A)、Fe₂O₃(F) CaO (C) (Table 7, examples 4 to 11). The melt spinning property was excellent. The radiation resistance was also excellent as in example 1.

[ Table 7]

Selecting fly ash FA (7) as a silicon dioxide-alumina source, and additionally preparing a reagent SiO₂(S)、Al₂O₃(A)、Fe₂O₃(F) CaO (C) was tested (Table 8, comparative examples 9 to 16). In each of comparative examples 9 to 16, any of the "4 elements of the present invention relating to the composition" was absent.

If the value of [ S ] + [ A ] does not satisfy the lower limit of the element i), the viscosity of the melt becomes too low, and as a result, a yarn cannot be formed (comparative example 9). On the other hand, if the value of [ S ] + [ a ] exceeds the upper limit of the element i), the viscosity of the melt becomes too high, and therefore the dropping operation by gravity, which is a precondition for forming a yarn, is not exhibited, and a yarn cannot be formed (comparative example 10).

If the value of [ A ]/([ S ] + [ A ]) does not satisfy the lower limit of the element ii), the viscosity of the melt is too low, and as a result, a yarn cannot be formed (comparative example 11). On the other hand, when the value of [ a ]/([ S ] + [ a ]) exceeds the upper limit of the element ii), the viscosity of the melt is too high, and therefore, the dropping operation by gravity, which is a precondition for forming a yarn, is not exhibited (comparative example 12).

The results of the X-ray diffraction (XRD) spectrum showed that in comparative example 12, it was confirmed that Al-rich material was considered to be included₂O₃Phase induced formation of crystalline phases (fig. 4).

When the value of [ F ] does not satisfy the lower limit of the element iii), the radiation resistance is poor (comparative example 13). On the other hand, if the value of [ F ] exceeds the upper limit of the element iii), the viscosity of the melt is too low, and as a result, a yarn cannot be formed (comparative example 14).

When the value of [ C ] does not satisfy the lower limit of the element iv), the viscosity of the melt is too low, and as a result, a yarn cannot be formed (comparative example 15). On the other hand, if the value of [ C ] exceeds the upper limit of the element iv), the viscosity of the melt becomes too high, and therefore a yarn cannot be formed (comparative example 16).

[ Table 8]

Next, a formulation was attempted in which most of the silica-alumina source, the iron oxide source, and the calcium oxide were composed of thermal power generation waste (fly ash, clinker) and metal smelting waste (steel slag, copper slag) or volcanic rock as a natural resource (table 9, examples 12 to 18).

All of them satisfy "4 elements of the present invention relating to the composition", and are excellent in melt spinnability. The radiation resistance is also excellent.

[ Table 9]

Fig. 4 shows XRD spectra of a series of molten samples.

[A]/([S]+[A]) The samples (comparative examples 11 and 6) having a value of (d) not exceeding the upper limit of the element ii) of the present invention were amorphous, but it was confirmed that in comparative example 12 having a value exceeding the upper limit of the element ii), the sample was considered to be Al-rich₂O₃Phase induced formation of crystalline phases.

Even if the value of [ F ] is changed to a range near the upper limit of the element iii) of the present invention, the material is amorphous (comparative example 13, examples 8 and 9, and comparative example 14).

Fig. 5 shows a temperature self-recording curve (DTA curve) based on differential thermal analysis of inorganic fibers obtained through a series of experiments.

The inorganic fiber of the present invention is thermally stable even when it reaches about 800 ℃ (at least a temperature close to 700 ℃), and has a melting temperature of 1200 ℃ or higher.

Industrial applicability

The inorganic material of the present invention has excellent radiation resistance, and thus can be used in the nuclear energy field, the aerospace field, and the medical field.

By using in the radiation-irradiated portion of the apparatus/machine/component in these fields, radiation deterioration of the radiation-irradiated portion can be suppressed.

Examples of equipment, machines and components in the field of nuclear power generation include:

devices/machines/components for nuclear power generation,

Plants/machines/components for mining and processing uranium ores,

Apparatus/machine/part for secondary processing of nuclear fuel (including conversion/concentration/reconversion/forming/MOX manufacturing of the same fuel),

Equipment/machinery/components for storing/treating/reprocessing used nuclear fuel,

Equipment/machines/components for storing/treating/disposing of radiant waste,

Machines, parts, or parts for conveying uranium ores, secondary processed nuclear fuel products, spent nuclear fuel or radiant waste,

Other core related devices/machines/components.

More specific examples of the devices, machines and parts used for nuclear power generation include nuclear reactor buildings (including research nuclear reactors and test nuclear reactors), nuclear reactor storage vessels, nuclear reactor plant piping, and nuclear reactor deactivation treatment robots.

As devices/machines/components in the aerospace field, mention may be made of:

space base buildings, space stations, artificial satellites, planet detection satellites, space suits and the like.

Examples of devices, machines and components in the medical field include:

a medical device using a particle beam.

The inorganic material of the present invention is excellent in melt spinnability, and therefore is suitable for use as an inorganic fiber for a fiber-reinforced composite material. Can be further processed into roving, chopped strand, woven fabric, prepreg, non-woven fabric and the like according to the application. Examples of the matrix material (fiber-reinforced material) of the composite material include resin, cement, and the like. As the resin, a known thermoplastic resin or thermosetting resin can be used.

Another example of the use of the inorganic material of the present invention is as a material for three-dimensional printing. That is, when a kneaded product of the inorganic material powder of the present invention, wax, resin, or other carrier is used as a material for three-dimensional printing, a member having excellent radiation resistance can be produced without being limited in shape.

The above use examples are for the purpose of illustrating the effectiveness of the present invention, and do not limit the scope of the present invention.

Description of the symbols

1-electric furnace, 2-carbon particle heating tube, 3-hanger rod, 4-opening, 5-fiber, D-electric furnace external diameter, H-electric furnace height and D-electric furnace opening diameter.