JPS6121915A - Manufacture of titanium compound fiber - Google Patents

Abstract

PURPOSE:To obtain titanium compound fibers in a high yield at a low cost by using natural titanium oxide as a starting material and controlling the blending ratio of the titanium oxide to an alkali metallic compound and the directional solidification of a product produced by a reaction under melting. CONSTITUTION:Natural rutile sand and/or natural anatase sand is mixed with an alkali metallic compound in 1.5-2.5 molar ratio of TiO2/M2O (M is the alkali metal), and they are heated and brought into a reaction under melting. The product is directionally solidified while controlling the temp. gradient in one or plural directions to obtain an aggregate of crystalline fibers. Soluble matter is leached out of the aggregate, and at the same time, the fibers are split. The split fibers are dried or baked.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for producing titanium compound fibers useful as fireproofing materials, heat insulating materials, friction materials, reinforcing materials, and the like.

[Prior art and problems]

Potassium titanate fiber (K2O・nTioz), typically potassium hexatitanate fiber (KzTi60+3), is
It is a fiber with excellent properties such as heat resistance, heat insulation, abrasion resistance, and reinforcing properties, and is seen as a promising alternative fiber for asbestos. For example, reinforcing materials for plastics and cement;
Brake linings for automobiles, heat-resistant materials, etc. are the most anticipated applications for asbestos substitute fibers.

Potassium titanate fibers can be produced by firing a mixture of titanium dioxide (T i O□) and potassium carbonate (KzCOs) at an appropriate temperature for a certain period of time; In the hydrothermal method, which is synthesized under high pressure and heating conditions in the presence of water, anhydrous potassium molybdate (KxM o 04) is added as a fluff to titanium dioxide and potassium carbonate and melted, and a crystalline fiber is produced by a dissolution/precipitation reaction. Flux methods and other methods have been developed to grow .

However, although potassium titanate fiber is highly expected to expand and diversify its uses as a potential alternative to asbestos, little progress has been made so far. The biggest reason for this is that the manufacturing cost is too high, and although it is acknowledged that they have excellent properties, the reality is that they cannot be replaced economically. Furthermore, the potassium titanate fibers selected by conventional manufacturing methods are extremely small, with a maximum length of around 100 microns, which is one of the main reasons why their practical application to heat insulating materials and the like has been delayed.

Recently, as a new manufacturing method for potassium titanate fiber,
A manufacturing method called the melting method was developed (Journal of Ceramics Association, 90 (1) 1982. p. 19-23).

In this method, a mixture of titanium dioxide and potassium carbonate is heated, melted and reacted, and then rapidly cooled and solidified to form potassium nititanate (KzTizOs) as the initial phase.
A lump, which is an aggregate of crystalline fibers consisting of ). According to this method, each fiber of potassium hexatitanate fiber (K2Ti6O13), potassium tetratitanate fiber (KzTLO4), and titania fiber (TiO□) is can get.

Compared to various conventional manufacturing methods, this melting method has features such as a simpler process, lower cost, and the possibility of continuous production, and has great industrial value. It is.

However, in order to promote the industrial practical use of potassium titanate fibers and the expansion and diversification of their uses, it is necessary to further reduce manufacturing costs. In each of the above manufacturing methods, extremely expensive highly purified purified titanium oxide (
99% or more) is used, and the raw material cost accounts for a high proportion of the manufacturing cost, which is the biggest barrier to cost reduction.

[Problem of invention]

The present invention aims to reduce the manufacturing cost of titanium compound fibers, focuses on natural rutile sand and natural anatase sand as raw materials for titanium dioxide in place of highly purified titanium oxide, and as a result of intensive research, utilizes the process of the above-mentioned melting method. By controlling the blending ratio of natural rutile sand or natural anatase sand and an alkali metal compound such as potassium carbonate in the preparation of molten raw materials, and the cooling conditions in the cooling and solidification process of the molten reaction product, it is possible to crystallize titanium compounds. It is possible to form and defibrate high-quality fibers, and through subsequent secondary treatment, fibers with improved properties can be obtained at high yields, and compared to conventional production methods using high-purity purified titanium oxide as a raw material. The present invention was completed based on various findings such as the ability to obtain new fibers that could not be manufactured.

[Technical means and effects]

The method for producing titanium compound fibers of the present invention includes a melting step of heating and melting a mixture of titanium oxide and an alkali metal compound, and cooling the molten reaction product to form a bundle of crystalline fibers made of alkali metal nititanate. A cooling solidification step to obtain a lump that is an aggregate, an elution and defibration step in which soluble substances are eluted from the lump and the bundled fibers are separated from each other, and a step in which the defibrated fiber is dried or fired. A method for producing a titanium compound fiber comprising: in the melting step, either natural rutile sand or natural anatase sand or a mixture thereof as a titanium oxide, an alkali metal compound, and "l' i 02/ M2O ( (M represents an alkali metal) are mixed so that the molar ratio is 1.5 to 2.5, heated and melted, and in the cooling solidification step, the molten reaction product obtained above is unidirectionally mixed. The composition and purity of natural rutile used as a special titanium oxide, which is characterized by being directionally solidified under the control of temperature gradients in multiple directions, varies slightly depending on the region of production and brand, but generally T r 02 It is about 95% by weight or more, and contains Fe2O3 and Z r 0 as impurities.
2, S + 02, CrzO3, V2O5, Nb2
O5, Aj! 2o3, Mno.

CaO, MgO1], S, etc. are included. Natural anatase sand generally has less TiO than the natural rutile sand mentioned above.
It has a similar composition to Habo, except that 7 has a rather low impurity content of about 90% or more.

Some of the elements contained in the raw material as impurities are extracted in the elution and fibrillation process, and most of them are contained in the fibers as fiber constituent elements.

The titanium compound fiber obtained by the method of the present invention can be represented by the following general formula.

MzO・n (Tt+M') 02・m FI
zO・・(1)u (Ti+M′)Ot・vHgOHH
HCm) Mx(Ti, M')s O+i HmHzo
HHH (I [l] In each formula, n is a positive number of 8 or less, m is 0
or a positive number of 4 or less, U is a positive number of 4 or less, ■ is 0 or a positive number of 2 or less, X is a positive number of 2 or less, M is Ni, Na, Li
alkali metal elements such as Mg, Ni, M′ derived from impurities of natural rutile sand or natural anatase sand,
Cu, Co, Zn, A1) Fe, Cr.

Ca, Ga, St, Nb, Zr, ,V, ,Mn,P.

Represents various elements such as S. Note that the above formula (1) is generally expressed as M
X (Tie-x7z+ M'I[X/Z) 0
It has two chemical compositions: 16 and Mx(Ti8-XI M′llK ) 016.

However, M'n is one of the elements represented by M' above.
Divalent elements such as Mgs Ni, Cu, Ca, Zn,
M's is Ai! of the elements represented by M'! , Fe.

Each represents a trivalent element such as Cr − or Ga. Typical examples of titanium compound fibers represented by the general formulas (1) to (III) above include n-G, m=0.M=K) in the Kz(Ti,M')ao+s(CI) formula. Potassium hexatitanate fiber, Kg (Ti, M') 40v (In formula (1), n
-4, m=o, M=K), Kg(Ti, M')1)016 ((I [I) formula, X-2, m=Q, M=K ), Hz(Ti, M')zo, s HzO((T
I) In the formula, u = 2, -2), crystalline titanate fiber, (Ti, M') Oz (In the formula (II), u =
1, V=O), and the like.

The melt reaction raw materials in the present invention are natural rutile sand and/or natural anatase sand (hereinafter represented by natural rutile sand, sometimes simply referred to as "natural rutile sand") and an alkali metal compound, TiO2/Mt
They are prepared by mixing O (M is an alkali metal) in a molar ratio of 1.5 to 2.5. T i O□/M! 0
The reason for limiting the molar ratio to 1.5 to 2.5 is that if it deviates from this range, fibers will not be formed in the cooling and solidifying process, or even if they are formed into fibers, no matter what defibration treatment is performed afterwards. This is because it is not defibrated. Formation of alkali metal titanate fiber aggregate during fiberization during cooling and solidification process)
It must be within the above range to enable the subsequent defibration. A more preferable molar ratio is 1.8 to 2.2. Note that the alkali metal compounds include Na,
Examples include carbonates and hydroxides of Rb and Cs. Potassium carbonate (K 2 CO3) is particularly suitable, and potassium hydroxide (KOH) can also be used with good results.

The above raw material mixture is charged into a melting crucible and heated to a temperature higher than its melting point to sufficiently carry out a melting reaction, and then the molten reaction product is cooled and solidified to form an alkali metal nititanate (M2 ( A lump, which is a bundle-like aggregate of crystalline fibers of Ti, M')ZOS), is obtained.

The cooling solidification is carried out by bringing the molten reaction product into direct or indirect contact with a cooling medium and cooling the molten reaction product by applying a unidirectional or multidirectional temperature gradient. Directional solidification in each given direction,
Crystalline fibers grown along each direction are formed. The temperature gradient is controlled between 0.5°C/double and 35°C/fl. If the bulk gradient is gentler than 0.5°C/L, the crystallinity will be poor and the fibers will be short, while if a steep temperature gradient of more than 35°C/N is applied, crystallization (fiberization) will be insufficient. This is because an amorphous part is formed. A preferable temperature gradient is 2 to b. When the product is natural anatase sand or a mixture of natural anatase sand and natural rutile sand, the temperature gradient is higher than in the case of natural rutile sand alone. Since the viscosity is high and it is easy to become amorphous, the temperature gradient is
It is desirable to set it relatively high within the above range. Although it is not particularly necessary to control the cooling rate of the molten reaction product until it reaches the freezing point, it may normally be about 0.7 to b.

The above-mentioned cooling assimilation process is carried out by using a cylinder or container having an appropriate shape as a cooling body, pouring the molten reaction product into the cooling body, and cooling the product by conduction heat transfer to the cooling body. The cooling body may be made of metal such as iron or copper, various ceramics, or graphite.

FIG. 1 shows an example in which a cylindrical body (1) is used as a cooling body, and a molten reaction product is poured into it to cool it.

A temperature gradient is given to the molten material in the cylinder (1) between the surface part, which is the cooling surface, which is in contact with the surface of the cylinder body and has the lowest temperature, and the center part, which is separated from the cooling surface and has the highest temperature. As a result, a bundle-like aggregate of fibers (F) grown perpendicular to the inner surface of the cylinder and converging toward the center is formed.

In Figure 2, a container (2) with a rectangular cross section is used as a cooling body,
This is an example in which a temperature gradient is formed in the vertical direction of the inner surface to cool and solidify the molten reaction product.

Inside the container, an aggregate of fibers (F) is formed that grows perpendicular to the inner surface of the container and substantially parallel to the center thereof.

Figure 3 shows two cylindrical bodies with different diameters (3, 1.3, 2
) are set up concentrically, and the melt is poured into a space with a donut-shaped horizontal cross section defined by two cylindrical bodies, with the surface of the inner cylinder and the surface of the outer cylinder serving as cooling surfaces. This is an example in which temperature gradients in opposite directions are formed in each of the inner and outer regions of the space, with a substantially central portion as a boundary, thereby cooling the space. In this case, a bundle-like aggregate of fibers (F) is formed that grows toward the center from each of the surfaces of the outer cylinder and the inner cylinder.

FIG. 4 shows an example in which an appropriate number of metal pieces (10) are inserted into a cylindrical body (4), and a molten reaction product is poured into the metal pieces and cooled. Temperature gradients occur in the molten reaction product in various directions depending on how the iron pieces are inserted and installed, and crystalline fibers ( F) bundle-like aggregates are formed.

Figure 5 shows a gold plate placed approximately in the center of the cylindrical body (4).
This is an example in which 1(1)) was wound up into several layers and stood upright, and the molten reaction product was poured into it and cooled. In this case, the temperature of the molten reaction product is the lowest at the part in contact with the cylinder surface (,
In addition to observing the formation of crystalline fibers that grew perpendicular to the surface and toward the center of the cylinder, crystalline fibers (the fiber length of which is
(shorter than those grown from the inner peripheral surface side of the cylinder) is formed.

Still another method is to use a centrifugal force casting method, in which a metal, ceramic or graphite mold is used as a cooling body, and the molten reaction product is cast while rotating the mold around its axis, and the centrifugal force is applied. By forming a cylinder of the molten reaction product along the inner surface of the mold and cooling it, it is also possible to form crystalline fibers that grow perpendicular to the inner wall surface of the mold and toward the mold axis.

Each of the above cooling solidification methods is a hatch method, but as a continuous processing method, for example, a cylindrical mold made of graphite, ceramic or metal with an appropriate wall thickness is used as a cooling body, and It is possible to apply a so-called continuous casting method in which a molten reaction product is poured in from the mold, solidified while being cooled, and then continuously pulled out from below.

Furthermore, as an alternative method for continuous processing, a plurality of plate-like standing wall members that protrude radially from the surface of the drum having an appropriate outer diameter are installed along the drum axis direction. A plurality of grooves partitioned by vertical wall members with the outer peripheral surface as the bottom are formed, and these grooves are used as cooling bodies.The drum shaft is installed horizontally and connected to a rotation drive device, and the drum shaft is installed continuously or intermittently at an appropriate rotation speed. The process involves pouring the molten reaction product into the grooves from above the drum while rotating the drum, cooling and solidifying it, and when the grooves point downward, the cooled solidified product (lumps) is released from the grooves. It is also possible to repeat the process sequentially for each groove while the drum rotates.

In each of the above cooling solidification methods, it is important to heat the cooling body to an appropriate temperature (approximately 30 to 300°C) or cool it as necessary to prevent excessive excess at the contact surface of the molten reaction product with the cooling body. This is preferable because it not only prevents amorphization due to rapid cooling, but also forms a temperature gradient suitable for the growth of crystalline fibers and promotes the formation of well-developed and healthy fibers. In the examples of FIGS. 4 and 5, if necessary for adjusting the temperature gradient, the cylinder (4) can be used as an auxiliary cooling body in addition to or in place of heating or cooling. Iron piece (lO
) or gold (1)) at an appropriate temperature. Furthermore, in the cooling assimilation method using centrifugal casting, the heated air inside the mold, which is heated by radiant heat from the molten reaction product injected into the mold, can also be used to adjust the temperature gradient. If necessary, air at an appropriate temperature may be blown into the mold.

Crystalline fibers [M2 (Ti,
The aggregate, which is a bundle-like aggregate of M')zos), is then subjected to leaching of soluble substances and defibration treatment. This treatment can be carried out using water, boiling water or acid solutions. Through this elution and fibrillation treatment and the subsequent secondary treatment conditions, various titanium compound fibers represented by the general formulas [I] to (Ill) can be obtained. Below, when M is potassium (the primary phase crystalline fiber is Kz(Ti, M
An example of the fiber obtained by the elution defibration treatment and subsequent secondary treatment will be explained using the potassium nititanate fiber (205) as a representative example.

Cold water treatment: When the lumps are immersed in water, potassium ions, etc. are eluted and the bonds between the fibers are broken.

Elutes potassium ions to a predetermined level (dealkalization)
After that, the potassium tetratitanate fiber (Kz(Ti.

M')aOq) can be obtained. In addition, after further proceeding with dealkalization, potassium hexatitanate fiber (K z (T i
, M')6013) can be obtained. Note that the dealkalization state can be controlled by measuring pH.

Boiling water treatment: The lumps are immersed in boiling water to sufficiently elute soluble substances and defibrate them. In this case, before immersing in boiling water, it may be once immersed in cold water to defibrate it, and then treated with boiling water for elution treatment. After elution and fibrillation, washing with water, approximately 1000
By heat treatment at
□-Kz(Ti, M')e016, Kg(Ti
, M')6013) can be obtained.

One of the characteristics of the present invention is that the above three-phase composite fiber can be obtained.
It is one. In the conventional manufacturing method using highly purified titanium oxide as a raw material, the fiber obtained by treating the lump with boiling water is potassium hexatitanate fiber, but in the present invention using natural rutile sand, preprite is attached. A composite phase fiber is obtained.

This is due to impurities (Fe2Q) contained in natural rutile sand.
This is because 3, A e 203 , Crz03 , S 10R , etc. are utilized as the main components of preprite.

- Acid treatment: The block is immersed in an acid solution, for example a 0.5 M aqueous hydrochloric acid solution. After defibration with an acid solution, extraction of all potassium ions and replacement with hydrogen ions, washing with water and drying (air drying), crystalline dititanic acid fibers with a layered structure (Hz ( T i, M') z Os・H
2O3 can be obtained. In addition, if the nititanic acid fiber is dehydrated and fired, titania fiber [(Ti, M')O□
] is obtained. In this case, the firing treatment temperature is approximately 900'
If it is below C, it will be an anatase phase, and if it is about 1) 50 degrees Celsius or higher, it will be a rutile phase, and if it is fired at a temperature between that, titania fibers with a mixture of rutile and anatase phases will be obtained.

Another feature of the present invention is that the above-mentioned rutile fiber ((Ti, M')O However, when attempting to obtain rutile fibers, 1) When fired at a temperature of 50°C or higher, although a phase transition to the rutile phase is observed, it becomes powdery and loses its fiber form, resulting in the inability to obtain rutile fibers. I can't.

In the present invention, which uses natural rutile sand or natural anatase sand, this problem does not occur and good rutile fibers can be obtained. In this case as well, it is thought that impurities in the raw materials are involved in the formation of rutile fibers.

〔Example〕

The component compositions (wt%) of the natural rutile sand and natural anacuse sand used in the following examples are as follows. The particle size is mostly around 100 μm. In addition, since each sand melted well, there was no need for grinding, and it was used as it was.

Natural rutile sand (from Australia) T i 02:
95.6%, Fez Os: 0, 6%, p:
o, o1%, S: 0. '02%, 7. rOz:
o, 7%, CrzC1+: 0.3%, S i 02:0
．． 6%, V2O3: 0.7%, Nbzos: o, a%,
AI! 203: 0.4%, MnO: 0.01
%, CaO: 0.03%, MgO: 0.03%, the remainder being a trace amount of CO1Ga, etc.

Natural anatase sand (from Brazil) T i O2: 90.7%, Fe40: +: 1.8%,
A 7!20342.22-3.0%, CaO: 0
．． 13-0.4%, CrzO3:0.001%, M
gO: 0.008-0.1%, MnO: 0°05
%, N1) 20S: 1.02%, pzos: 0.2-0
．． 41%, S i 02: 0.98%, V2O
5: 0.15%, Z r Oz 20, 20%,
As: 0.8 ppm, S: 0.013
%, H: 0.07%, deposits 0.8%, the remainder being a trace amount of CO1Ga, etc.

Top of the cliff panel (1) Melt reaction treatment +1) ffI melt raw materials: natural rutile sand, industrial potassium carbonate (purity 99.9%), total 300 g.

T i O□/20 (molar ratio) = 2° (2) Melting conditions: 1) 00°C x 2. Hr (platinum crucible, capacity 500
cc).

(II) Cooling solidification treatment It was cooled and solidified using the following seven methods.

(1) An iron cylindrical body (thickness 15
**, inner diameter 60m5゜ (no preheating) was installed upright, and the molten reaction product was injected. Temperature gradient 3.5-18.5°C/-rin.

Fibers grow vertically from the inner surface of the cylinder toward the center. Fiber length after defibration: 1 to 2 IIm (approximately 2
0 ml), 0.2 to 0.5 ml (region 20 to 30 ml from the inner circumferential surface of the cylinder).

(21U-, in the same cooling method as described in (1), the iron cylinder was preheated to 100°C.Other conditions were the same as in (1).Temperature gradient 4.5~b The fibers were placed on the circumferential surface of the cylinder. Grows vertically to the center.

(3) Graphite cylindrical body (wall thickness 1
3 mm, inner diameter 8 mm) was set up as a cooling body, and the molten reaction product was injected into it. Temperature gradient 5-13℃ 7/Dragon.

Fibers grow perpendicular to the wall inside the cylinder. Fiber length: approximately 1 long (after defibration).

(4) A ceramic (alumina) approximately rectangular cylinder (wall thickness: 25 mm, cross-sectional area: 8 cIa) was erected on a copper plate (wall thickness: 0.6 mm).

into which the molten reaction product is poured. Temperature gradient 3~
b Fibers grow perpendicular to the bottom and inner wall of the cylinder.

Fiber length approximately 3 to 4 long (after defibration).

(5) Iron cylindrical body (thickness 1
5 mm, inner diameter: 60 mm), pour the molten reaction product into this, and add 1 plate iron piece (cross section: 15 fi x 5 mm).
) Scattered insertion of books. Temperature gradient 8-b Fibers grow in the vertical direction from the inner wall of the cylinder and the surface of each iron plate. Fiber length is approximately 1 to 21 cm (after defibration).

(6) Iron plate (thickness 4.5mm) On top of the iron cylinder (thickness 1
At the same time, a wire mesh (iron wire diameter 0.8 fin, 6#) was rolled up into several layers to form a tube (30 wire diameter).
is inserted into the center of the cylindrical body, and the molten reaction product is poured into the cylindrical body.

Temperature gradient 3.5~b Fibers grow perpendicular to the wall and bottom of the cylinder.

Fiber length is approximately 2 to 3 lengths (after defibration).

(7) In the cooling method of (5) above, the iron cylindrical body is
The iron pieces were preheated to 0° C. and 70° C., and the molten reaction product was poured in with other conditions being the same. Temperature gradient 4~
6.5℃/fin.

Fibers grow perpendicular to the wall and bottom of the cylinder.

Fiber length is approximately 3 to 4 fibers (after defibration).

(Ill) Elution and defibration treatment and drying or calcination treatment Each lump obtained through the above cooling and solidification treatment was subjected to the following six treatments.

+1) Cold water treatment and calcining The lumps are immersed in water, soluble substances are eluted and defibrated, and the pH of the leachate is measured while dealing with alkalization.
Firing was performed at 1000° C. for 3 hours to obtain potassium hexatitanate fibers (Kg (Ti, 'M') 6013).

(2) Cold water treatment and firing The lumps were immersed in water, soluble substances were eluted and defibrated, and the specified dealkalization was achieved while measuring the pH, followed by firing at 900°C for 3 hours. Potassium tetratitanate fiber (K 2 (T i , M') 40
q] was obtained.

(3) Boiling water treatment and firing The lumps were immersed in boiling water for 1 hour (<2 g), washed with water, and then fired at 1000°C for 3 hours to produce rutile-briplite-potassium hexatitanate composite fibers (
(Ti, M') O□-Kg (Ti, M') *
01b Kz (Ti, M')6013) was obtained.

This fiber exhibits a darker brownish tone than the potassium hexatitanate fiber.

(4) Acid treatment and air drying The lumps were immersed in a 0.5M hydrochloric acid aqueous solution for 24 hours (2 g/I
l), washed with water (pH neutral), and then air-dried to obtain layered crystalline titanate fibers (Hz (T
i, M')205 .HzO] was obtained.

(5) Acid treatment and baking The block was immersed in a 0.5 M hydrochloric acid aqueous solution for 24 hours (28/
l) After washing thoroughly with water (pH neutral),
The anatase fiber ((T
i, M')02) was obtained.

(6) Acid treatment and baking The lumps were immersed in a 0.5M hydrochloric acid aqueous solution for 24 hours (2 g/J
), wash thoroughly with water (pH neutral), and then 1) 5
The rutile fiber [(Ti, M'
)O□] was obtained.

(1) Melt reaction treatment + 1) Molten raw materials: Natural rutile sand and natural anatase sand (weight ratio 1:1), industrial potassium carbonate (9
9.9%). Total amount 300g.

Ti0z/KzO (mole ratio) = 1.9 (2-melt conditions? 1200℃ x 1.5 hours -) /L / /L
/ acupuncture point, capacity 500 cc).

(It) Cooling and assimilation treatment (1) An iron cylinder (wall thickness: 15 mm, inner diameter: 60 mm, preheating temperature: 150°C) is erected on a laminate of potassium titanate plate (upper layer) and asbestos (lower layer), Pour in the molten reaction product. Temperature gradient approximately 5~b Fibers grow perpendicular to the wall surface inside the cylinder. The fibers in the center are slightly thinner. Fiber length: Approximately 0.5 to 1 strand (after defibration).

(2) Iron cylindrical body on iron plate (plate thickness 4.5 mm) wall thickness 1
At the same time, a wire mesh (iron wire diameter 0.8 m) was rolled into a cylinder shape (diameter 30 m) in the center.
the molten reaction product into the cylinder. Temperature gradient approximately 3.5~b Fibers grow perpendicular to the wall surface of the cylinder. Fiber length is approximately 1~
21) 1) (after defibration).

(Ill) Elution defibration treatment and secondary treatment Example 1 (
1) By the same treatment as (1) [cold water treatment + 1000°C firing] in 1), potassium hexatitanate fibers were
3) A rutile-preplite-potassium hexatitanate composite phase fiber was produced using the same process as [boiling water treatment + 1000°C firing], and a layered crystalline titanate fiber was produced using the same process as (4) [acid treatment + air drying]. , and same (6) [acid treatment +1]
Rutile fibers were obtained by the same treatment as [50° C. firing].

Example 3 (1) Melt reaction treatment (1) Molten raw materials: Natural anatase sand, industrial potassium carbonate (9 (1.9%). Total amount 300 g.

T i Ot / KzO (molar ratio) = 2.1.

(2) Melting conditions: 1) 50°C x 2 hours (aluminum crucible, capacity 500cc).

(n) Cooling and solidification treatment (1) An iron cylindrical body (wall thickness 151 m, inner diameter 6 (
ifl. A preheating temperature of 45°C was set up, and the molten reaction product was injected. Temperature gradient 5-b Fibers grow perpendicular to the inner wall of the cylinder. The fibers in the center are slightly thinner. Fiber length: approximately 0.1 to 1 mm (after defibration).

(2) Iron plate (plate thickness 4.5 mm) J second iron cylindrical body (
A cylinder with a wall thickness of 15 mm and an inner diameter of 6 mm is erected, and a wire mesh (iron wire diameter of 0.8 mm) is rolled into a cylinder shape (30 mm in diameter) and inserted into the center of the cylinder, and the molten reaction product is poured into the cylinder. Pour. Temperature gradient 3.5~b Fibers grow perpendicular to the wall surface inside the cylinder. Fiber length is approximately 1~
2 dragons (after defibration).

(II+) Elution defibration treatment and drying or calcination treatment (1) in CDI of Example 1 [cold water treatment +100
Potassium hexatitanate fibers were produced using the same process as in (3) [boiling water treatment + 1000°C firing], and rutile-preprite-potassium hexatitanate composite phase fibers were produced in (4) [by the same process as in (3) [boiling water treatment + 1000°C firing]]. A layered crystalline titanate fiber was obtained by the same treatment as in (5) [acid treatment + 900°C firing], and anacuse fiber was obtained by the same treatment as in (5) [acid treatment + 900°C firing].

The fiber length of the titanium compound fibers in each of the above examples varies depending on the processing conditions in the cooling solidification process, elution and defibration process, etc., but it is approximately 0.5 dragons or more (0.5 to 4 dragons), compared to the conventional one. Comparatively long.

FIG. 8 shows the fibers obtained by processing the agglomerates.

The fibers were potassium hexatitanate fibers (K2 (Ti, M') 601) obtained by firing at 1000 °C after cold water treatment.
3) (the processing conditions are (I[I)(
1)), the same figure (1) shows the fiber group (magnification: ×30),
The figure [■] is an enlarged appearance of a single fiber (magnification: X100O)
are shown respectively. Incidentally, an X-ray powder diffraction pattern of the above fiber is shown in FIG.

〔Effect of the invention〕

According to the method of the present invention, various titanium compound fibers can be produced at extremely low cost and in high yield using natural rutile sand or natural anatase sand as a raw material.

According to the present invention, it is possible to obtain fibers having a longer fiber length than those obtained by conventional production methods, and the present invention is useful as a method for producing industrial fibers.

Furthermore, according to the present invention, it is possible to produce rutile-preprite-alkali metal hexatitanate composite phase fibers and rutile fibers that cannot be obtained by conventional production methods using highly purified titanium oxide as a raw material.

Furthermore, the invention provides fibers with improved properties.

For example, regarding heat resistance, the melting point of potassium hexatitanate fiber is approximately 1370°C, and that of preprite fiber is approximately 150°C.
0°C, that of titania fiber is extremely high at about 1840°C, indicating that it has excellent heat resistance.

It also has excellent alkali resistance and chemical resistance that surpasses asbestos fibers. Furthermore, potassium hexatitanate,
It is extremely hard, with a Mohs hardness of approximately 4, and has excellent wear resistance. Furthermore, the fibers obtained according to the present invention have properties superior to conventional fibers in terms of heat insulation properties. FIG. 7 shows the measurement results of thermal conductivity of fibers obtained by the method of the present invention using natural rutile sand as a raw material and fibers obtained by a conventional method using highly purified titanium oxide as a raw material. In the figure, (1) is the rutile fiber C (
Ti, M') 02), (1') is rutile fiber obtained using highly purified titanium oxide as a raw material, (TiO2)
, (2) is the potassium hexatitanate fiber (K2 (Ti, M') 6013) obtained by the present invention, and (2') is the potassium hexatitanate fiber obtained using high-purity purified titanium oxide as a raw material <Kz TL, O+:+) and (3) respectively indicate the thermal conductivity of the rutile-preplyte-potassium hexatitanate fiber obtained according to the present invention.

As shown in the figure, when comparing fibers of the same type, the fibers obtained by the present invention have lower thermal conductivity, and the thermal conductivity of the three-phase composite fibers is also extremely low, resulting in poor thermal insulation properties. It can be seen that

Various fibers obtained by the method of the present invention are fireproof/insulating materials,
It is useful as a constituent material for heat-resistant materials, friction materials, filtration materials, catalyst carriers for high-temperature applications, sound-absorbing materials, etc., or as composite reinforcing materials for cement, plastics, metals, etc. It is also useful as a material for crystalline dititanic acid fibers and titania. Fibers also have adsorption properties for ions, etc., so they are suitable as constituent materials for waste treatment barrier layers in nuclear power facilities, for example.Furthermore, titania fibers are useful as constituent materials for insulating materials, dielectric materials, etc. It is.

In this way, the present invention makes it possible to inexpensively and reliably produce titanium compound fibers useful for various uses, and to expand and diversify the uses as a substitute for conventional asbestos.
Its industrial value is extremely large.

[Brief explanation of drawings]

Figures 1 to 5 are schematic explanatory diagrams of the cooling assimilation method of the molten reaction product and the state of crystalline fiber production (in each figure, (1) is a longitudinal sectional view, (II) is a XX sectional view), Figure 6 is an X-ray powder diffraction diagram of the fiber obtained by the present invention, Figure 7 is a graph showing the thermal conductivity of various titanium compound fibers, Figure 8 (1),
(II) is a photomicrograph substituted for a drawing showing an example of fibers.

Claims (1)

[Claims] (1) A melting step in which a mixture of titanium oxide and an alkali metal compound is heated and melted to react; a cooling solidification step in which the molten reaction product is cooled to produce a lump that is an aggregate of crystalline fibers; A method for producing titanium compound fibers, comprising an elution and defibration step of eluting soluble substances from a substance and defibrating it, and a step of drying or firing the defibrated fibers, the method comprising the steps of: oxidizing titanium in the melting step; As a product, one of natural rutile sand and natural anatase sand or a mixture of both is mixed with an alkali metal compound such that the molar ratio of TiO_2/M_2O (where M represents an alkali metal) is 1.5 to 2.5. 1. A method for producing titanium compound fibers, which comprises: heating and melting reaction by mixing with a titanium compound fiber; and, in a cooling solidification step, directional solidifying the molten reaction product under control of a temperature gradient in one direction or in multiple directions.