JPS6121914A - 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 cooling rate of a product produced by a reaction under melting. CONSTITUTION:Natural rutile sand ans/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 reaction product is cooled at 0.7-25 deg.C/sec cooling rate to obtain an aggregate of crystalline fibers. Soluble matter is leached out of the aggregate and at the same tie, 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/insulating materials, friction materials, reinforcing materials, etc.

[Prior art and problems]

Potassium titanate fiber (KzO-n TiOx),
Typically, potassium hexatitanate fiber (KzTLO+3)
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 (TiOz) and potassium carbonate (KICOn) at an appropriate temperature for a certain period of time, or by combining titanium dioxide and potassium hydroxide (KOH) with water. In the presence of high pressure and heat conditions, the hydrothermal method is used to melt titanium dioxide and potassium carbonate by adding anhydrous potassium molybdate (KMOO4) as a flux.
The Franks method, which grows crystalline fibers through dissolution/precipitation reactions, has been developed.

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 obtained by conventional manufacturing methods are extremely small, with a maximum length of around 100 microns, which is the main reason for the delay in their practical application as heat insulating materials.

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

In this method, a mixture of titanium dioxide and potassium carbonate is heated to undergo a melting reaction, and then rapidly cooled and solidified to produce potassium nititanate (K2Ti2O5) as the initial phase.
A lump, which is an aggregate of crystalline fibers consisting of ). According to this method, potassium hexatitanate fiber (K z T i b O
'+3), potassium tetratitanate fiber (KzTLO
l), titania fiber (TiO□) can be changed.

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 (
Ti0299% 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 focuses on natural rutile sand and natural anatase sand as raw materials for titanium dioxide to replace high-purity purified titanium oxide, with the aim of reducing the manufacturing cost of titanium compound fibers, and as a result of extensive research, the present invention utilizes the melting process described above. At the same time, by controlling the blending ratio of natural rutile sand or natural anatase sand ° with 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 It is possible to form and defibrate crystalline fibers, and the subsequent secondary treatment yields fibers with improved properties, which cannot be produced using conventional manufacturing 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 novel fibers that were not previously available.

rTechnical 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 an alkali metal nititanate. a cooling solidification process to obtain a lump, which is a bundle-like aggregate of crystalline fibers, an elution and defibration process in which soluble substances are eluted from the lump and the bundle-like fibers are separated from each other; A method for producing a titanium compound fiber, which includes a step of drying or firing the fiber, and in the melting step, natural rutile sand or natural anatase sand, or a mixture thereof, is used as a titanium oxide, an alkali metal compound, and TiO□ /MzO (where M represents an alkali metal) are mixed so that the molar ratio is 1.5 to 2.5, and heated and melted. In the cooling solidification step, the molten reaction product is cooled. It is characterized by cooling at a rate of 0.7°C/sec to 25°C/sec.

The composition and purity of natural rutile sand used as titanium oxide differs slightly depending on the production area and brand, but it is generally about 95% by weight or more of TiQ2, and as impurities,
Fe2O3, Z'r 02, S i 02, CrzO
3-, V2O5, NbzOs, Aj! zoz, Mn
O.

Includes CaO1Mg01p, s, etc. Natural anatase sand generally has a higher content of TiO□ than the natural rutile sand mentioned above.
It has a similar composition to Habo, except that it has a slightly lower content of about 90% or more and a higher content of impurities. Some of the elements contained as impurities in the raw material are extracted in the elution and fibrillation step, and most of them are contained in the fiber 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 (Ti, M′) 02 ・lTlH2O
...(1) u(Ti, M')Ox ・vH,o
... (II) Mx (Ti, M')a O+6・m
H2O・-(Ill) In each formula, . is a positive number of 8 or less, - 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 2 or less positive number, M is ni, Na, L
Alkali metal elements such as i, M' are Mg and Ni derived from impurities of natural rutile sand or natural anacuse sand.
,Cu,Co,Zn,,Aj! ,,Fe.

Cr, Ca, Ga, Si, Nb, Zr, V, M
n.

Represents various elements such as P and S. Note that equation (1) generally has M
x (Tin-xzz, M'x*yz) Olb and M x (Tie -X.

M’II8. )016.

However, M'm is one of the elements represented by M' above.
Divalent elements such as Mg, Ni, Cu, Ca, Zn, M
'II is Al, Fe, Cr among the elements shown by M'
, each represents a trivalent element such as Ga. Above (1) - (
As a representative example of a titanium compound fiber represented by the general formula I[[), Kz(Ti,M')bo++ ((1) 2, n
-6, m=Q, M=K) potassium hexatitanate fiber, Kz(Ti, M')409 (in equation (1), n-4, m=Q, M=K) Potassium tetraticunate fiber, Kz(Ti,M')8016 ((I[[) in the formula, X=2, m=0, M=K) preprite fiber, Hz(Ti,M')zOs・H, O < (n)
In the formula, u = 2, ■ = 2), (Ti, M') 02 (In the formula (II), u =
l, ■=0), 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, TiO□/Mho
(M is an alkali metal) are mixed so that the molar ratio is 1.5 to 2.5. The reason why the molar ratio of TiO2/MZO was limited to 1.5 to 2.5 is that if it deviates from this range, it will not form into fibers during the cooling and solidification process, or even if it becomes fibers, it will not be able to be processed by any subsequent defibration treatment. This is because it is not defibrated. It must be within the above range to enable fiberization in the cooling and solidification process (formation of alkali metal titanate fiber aggregates) and subsequent fibrillation. A more preferred molar ratio is 1°8 to 2.2. Note that examples of the alkali metal compound include carbonates and hydroxides of Na, Rb, and Cs. Especially potassium carbonate (
K*CO.

) is preferred, and the use of potassium hydroxide (K OH) also gives 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 (Mz( A lump is obtained which is a bundle-like aggregate of crystalline fibers of Ti, M') gos) (where M' represents an element derived from impurities of natural rutile sand). The cooling rate must be controlled between 0.7°C/sec and 25°C/sec. Setting the cooling rate to 0.7°C/sec or more is because
If it is cooled more slowly than that, although fiberization is possible,
This is because subsequent defibration is difficult, and the reason why the upper limit is set at 25°C/sec is that if the cooling is more rapid than that, crystallization will be hindered and the agglomerates will become amorphous powder lumps. . A more preferred cooling rate is 2.5°C/sec to 14°C/sec.

゛In addition, when the titanium dioxide raw material is natural anatase sand or a mixture of natural anatase sand and natural rutile sand, the viscosity of the molten reaction product is higher than in the case of only natural rutile sand, Since it is easy to become amorphous, it is desirable to control the cooling rate to be relatively low.

In addition, the cooling rate of the molten reaction product in the cooling solidification step is set to be fast at the beginning of cooling and slow near the freezing point, that is, the cooling rate gradually decreases in the process from the start of cooling to the start of solidification. To control it,
This is preferable in that it promotes fiber growth and forms well-developed long fibers. FIG. 1 shows a measured example of a preferred cooling curve for a molten reaction product. In this example, the average cooling rate from the start of cooling to the start of solidification is approximately 6°C/sec, with the cooling rate in the first half being 6°C/sec and the cooling rate in the second half being approximately 2°C/sec.
6°C/sec.

The cooling assimilation treatment of the molten reaction product can be carried out by various methods as described below. :For example, metal disc (
18-8 stainless steel etc.) is used as a cooling body, and the molten reaction product is coated on the surface with an appropriate layer (for example, 1 to 5
0 mm) and allowed to cool, it is cooled by conductive heat transfer to the cooling body, and crystalline fibers are observed to grow almost perpendicularly from the bottom surface. Due to the quality of the fibers obtained, the phase thickness is 25
It is preferable that it is below tm.

In addition, by using an iron plate as a cooling body, placing the molten reaction product together with the molten crucible on its top surface and bringing the bottom of the crucible into contact with the cooling plate surface, conductive heat transfer allows the molten reaction product inside the crucible to flow vertically from the bottom of the crucible. It is preferable to form a temperature gradient in the direction of cooling. According to this method, fibers are formed substantially perpendicular to the bottom and side wall surfaces of the crucible.

Alternatively, the molten reaction product is poured into a graphite cylinder, ceramic cylinder, or metal cylinder of suitable wall thickness with a circular or rectangular cross section as a cooling body, and the molten reaction product is poured into the cylinder wall. By cooling by conductive heat transfer, crystalline fibers grown perpendicularly to the wall surface of the cylinder are obtained. In addition, the molten reaction product is poured into the ring-shaped space formed by two concentric cylindrical vertical walls having an appropriate wall thickness, and the molten reaction product is poured into the space between the outer peripheral surface and the inner surface of the cylinder. Alternatively, the fibers may be grown from both the outer circumferential surface and the inner circumferential surface toward the center of the ring-shaped space by cooling both sides of the circumferential surface.

In addition, as a continuous cooling and solidification treatment method for the molten reaction product, for example, a graphite or metal cylindrical mold F having an appropriate wall thickness is used as the cooling body, and the molten reaction product is poured into the mold from above. It is possible to apply a so-called continuous casting method in which the material is solidified while being cooled and then continuously pulled out from above.

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 tram axis direction. A plurality of grooves partitioned by vertical wall members with the outer circumferential surface as the bottom are formed, and these grooves are used as cooling bodies.A drum shaft is installed horizontally and connected to a rotary drive device, and the drum shaft is installed horizontally and connected to a rotary drive device, and the grooves are used as a cooling body to continuously or intermittently operate the drum shaft at an appropriate rotation speed. While rotating it harshly,
The molten reaction product is poured into the groove from above the tram, cooled and solidified, and when the groove faces downward, the cooled and solidified product (
The operation of removing the lumps from the grooves may be repeated in sequence for each groove while the drum rotates.

In each of the above cooling methods, depending on the cooling conditions,
Preheating the surface of the cooling body to an appropriate temperature (approximately 30 to 300°C) is effective in preventing the molten reaction product from becoming amorphous due to excessive rapid cooling at the contact surface with the cooling body. That's true. However, if the temperature of the cooling body rises excessively due to continuous operation and the cooling capacity becomes insufficient, it is necessary to install appropriate cooling means such as a water cooling structure on the cooling body to obtain the required cooling rate. Bye.

Crystalline fibers (Mz(Ti,
The mass consisting of M')zos) is then subjected to leaching of soluble substances and defibration treatment. This treatment can be performed using water (cold water), boiled water, acid solution, or the like. Through this elution defibration treatment condition and the subsequent drying or firing treatment, alkali metal hexatitanate fibers (Mz(Ti, M') 6013) and alkali metal tetratitanate fibers (M2 (1" + + M')) 40
．． ],] Rutile-Bryprite-alkali metal hexatitanate composite fiber (T i , M') 02 M x
(T i.

M')lIo +b Mz("I'i, M'
)601. ), Oyohi f Tania fiber ((1'i,
Various derivatives such as M') O□] can be obtained. Below, M
is potassium, that is, the primary crystalline fibers constituting the agglomerate are potassium dititanate (Kg(Ti,
M') 205) T: The elution and fibrillation treatment, the drying or firing treatment, and the resulting fibers will be explained in a representative case.

Cold water treatment: When the lump is immersed in water, potassium 1, ions, etc. are eluted, and the bonds between the fibers are broken.

Elutes potassium ions to a predetermined level (dealkalization)
After that, it is heat-treated (calcined) at about 900°C to obtain potassium tetratitanate fiber (Kg (Ti1M') 409).Also, after further dealkalization, about 1oo
By heat treatment (firing) at 0° C., potassium hexatitanate fiber (Kz(Ti, M′) 6013) is 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, wash with water and leave for about 10 minutes.
By heat treatment at 00°C, rutile-preplite-potassium hexatitanate composite phase fiber ((Ti, M') O
□-Kz(Ti, M')e016 Kz(Ti,
M')6013) is obtained.

One of the features of the present invention is that the above three-phase composite fiber can be obtained. 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 (FezO) contained in natural rutile sand.
3, A It to 3-, Cr2e3, MgO, etc.) are utilized as the main components of preprite.

Acid treatment: The mass is immersed in an acid solution, for example 0.5 M aqueous hydrochloric acid. After defibration with an acid solution, extraction of all potassium ions and replacement with hydrogen ions, washing with water and drying (air drying), crystalline titanate fibers with a layered structure (Hz (Ti , M') 20% H2O3 can be obtained.If the nititanic acid fiber is dehydrated and fired, chikunia fiber ((Ti, M')0□) can be obtained.In this case, the firing temperature is about 900°C. If the temperature is below, it becomes an anatase phase, and if it is about 1) 50° C. or higher, it becomes a rutile phase, and if it is fired at a temperature between that temperature, titania fibers containing a mixture of rutile and anatase phases can be obtained.

Another feature of the present invention is that the above-mentioned rutile fiber ((Ti, M')02) can be obtained. In other words, in the conventional manufacturing method using highly purified titanium oxide as a raw material, it is possible to form anatase fibers, but if you try to obtain rutile fibers by firing at an fA degree of about 1) 50"c or more, it will change to the rutile phase. Although a phase transition is observed, the fiber becomes powdery and loses its fiber form, making it impossible to obtain rutile fiber.In the present invention, which uses natural rutile sand or natural anacouse sand, such a problem does not occur. (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.

Natural rutile sand (from Australia) T i O2:
95.6%, FezO5:0.6%, p:o, o1%,
S: 0.02%, Z r 02: 0.7%, Cr2O5
: 0.3%, SiOz: 0.6%, VzOs: 0.
7%, NbzOs: 0.3%, A j! go++:0.
4%, MnO: 0.01%, CaO: 0.03
%, MgO: 0.03%, the remainder being trace amounts of Co, Ga, etc.

Natural anatase fiber (made in Brazil) TiOz: 90.7%, FezO3: 1.8%,
A1!203: 2.22-3.0%, CaO:
0.13~O,'4%, Cr2O2:0.001
%, MgO: 0.008-0.1%, M
nO: 0°05%, NbzOs: 1.02%, pzos
: 0.2 to 0.41%, SiOz: 0.98%,
VzOs: 0.15%, Z r O2: 0.20%, A
s: 0.8 ppm, S: 0.01
3%, H: 0.07%, deposits 20.8%, the remainder being a trace amount of CO1Ga, etc.

Example 1 (1) Melt reaction treatment (1) Molten raw materials: natural rutile sand, industrial potassium carbonate (purity 99.9%), total 50g0TiO□/20
(Molar ratio) -2° (2) Melting conditions: 1) 00°C x 1) (r (Platinum crucible: inner diameter 50 mm, wall thickness 0.5 mm, flat bottom).

[■] Cooling assimilation treatment Conducted using the following six cooling methods.

Place the molten reaction product in the crucible on a 22mm thick iron plate (at room temperature).

Fibers grow vertically from the bottom of the crucible. Growth from the side wall surface is also observed. Average cooling rate: 3-b (5 dragons from the wall). Fiber length: approximately 20 (after defibration).

(2) Apply a layer of melted reaction product to a thickness of 1 on an iron plate (thickness of 2).
．． Pour out 5 to 2 dragons. Average cooling rate: approximately 5°C/sec.

An amorphous layer (approximately 1 inch thick) was formed at the contact area with the iron plate surface, but fibers grew on top of it. Fiber length 0.8u (after defibration).

(3) A stainless steel dish container is placed on an iron plate, and the molten reaction product is poured into the container to a thickness of 3 degrees.

Average cooling rate: approximately 13°C/sec.

Long fiber pieces 31 (
After defibration) relatively thick fibers are produced.

(4) Place a platinum-shaped dish container (wall thickness: 0.5 m5) on an iron plate, and pour the molten reaction product into it to a layer thickness of about 31 m5.

Average cooling rate: approximately 14°C/sec.

Relatively thick fibers were generated that grew vertically from the bottom of the dish container. Long fiber pieces 21) 1 (after defibration).

(5) Place a copper dish container (wall thickness 0.6 dragon) on the iron plate 1.
The molten reaction product is poured into this in a layer thickness of 10 to 15 mm.

Average cooling rate: approximately 2.5°C/sec.

Fibers grow vertically from the bottom and top of the dish container.

The average fiber length of the lower layer is approximately 2 fins, and the average fiber length of the upper layer is approximately 1) 1 (
(all after defibration).

(6) Place a copper plate vessel (wall thickness: 0.6 mm) preheated to 120°C on an iron plate, and pour the molten reaction product into it in a layer thickness of 5 layers. Average cooling rate: approx. °C/sec.

Flexible, relatively thick fibers are produced that grow vertically from the bottom of the dish container. Fiber length piece 41 (after defibration).

(I[l) Elution and defibration treatment and drying or calcination treatment Each lump obtained through the above cooling assimilation 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.
Potassium hexatitanate fibers (Kz (Ti, M') 6013) were obtained by firing at 1000° (x3 hours).

(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 (2 g/A) for 1 hour, washed with water, and then fired at 1000°C for 3 hours to form rutile-preprite-potassium hexatitanate composite fibers ((
Ti, M') Oz Kz (Ti, M') 1) 0
16-K2 (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 0.5M hydrochloric acid aqueous solution for 24 hours (2g/7
After drying, the layered structure titanate fiber [H2 (Ti7M) was washed with water (pH neutral) and air-dried.
')z○, Hz O) was obtained.

(5) Acid treatment and baking The block was immersed in a 0.5 M hydrochloric acid aqueous solution for 24 hours (2 g/
l) Rinse thoroughly with water (pH neutral), then
The anatase fiber (("
Fi, M')O□] was obtained.

(6) Acid treatment and baking The lumps were soaked in 1 volume of 0.5M hydrochloric acid for 24 hours.
l) After that, wash thoroughly with water (pH neutral), and then 1)
The rutile fiber [(Tt, M
')Oz) was obtained.

Example 2 (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 50g0 TiO□/K 20 (mole ratio) = 1.9 (2)
Melting conditions: 1200°C x Q, 5 Hr (Niaker crucible: inner diameter approximately 50mm, wall thickness 0.5n, flat bottom).

(II) Cooling and assimilation treatment A copper dish container (wall thickness: 0.6 m) is placed on an iron plate, and the molten reaction product is poured into it in a layer thickness of 5 mm. Average cooling rate is approximately 2°C/sec.

Fibers that grow vertically from the bottom of the dish container are generated. Fiber length approximately 2m (after defibration).

(2) Preheated copper dish container (meat J) to 120°C on an iron plate.
! J: 0.6 dragon) was placed, and the molten reaction product was not flowed out to a layer thickness of 5**. Average cooling rate: approximately 7°C/sec.

Relatively thick and flexible fibers that grow vertically from the bottom of the dish container. Fiber length approximately 1tm (after defibration).

(In) Elution defibration treatment and drying or firing treatment (1) in (III) of Example 1 [cold water treatment +1000
By the same treatment as in (3) [boiling water treatment + 1000 °C firing], potassium hexatitanate fibers were made into rutile-preprite-potassium hexatitanate composite phase fibers in (4). Layered structure titanate fiber was produced by the same treatment as (6) [acid treatment + 1].
Rutile fibers were obtained by the same treatment as [50° C. firing].

Example 3 (1) Melt reaction treatment (1) Melt raw materials: natural anatase sand, industrial potassium carbonate (99.9%). Total amount 50g0T i O□/
, O (molar ratio) = 1.9 (2) Melting conditions 71) 50
°C x 1 hour (aluminum crucible: inner diameter approx. 50 m, wall thickness 0.
5fi, flat bottom).

(II) Cooling assimilation treatment (1) Preheated copper dish container (wall thickness 0) to 120℃ on an iron plate.
．． 6 mm), onto which the molten reaction product is poured out in a layer thickness of 4 mm. Average cooling rate: approx. °C/sec.

Well-developed, relatively thick and flexible fibers grow vertically from the bottom of the dish container. Fiber length approximately 2 fins (after defibration).

(III) Elution defibration treatment and drying or firing treatment (X) in (III) of Example 1 [cold water treatment +100
The rutile-preprite-potassium hexatitanate composite phase fiber was produced by the same process as (3) [boiling water treatment + 1000°C firing]. Layered structure titanate fibers were produced by the same treatment as (5) [acid treatment + air drying].
Anatase fibers were obtained by the same treatment as [00°C firing].

The fiber length of the titanium compound fibers in each of the above Examples is approximately 11 m or more, which is longer than that of fibers obtained using conventional highly purified titanium oxide as a raw material, especially in Example 1.
(II) fil, (3), (4), (6), Example 2
The length of fibers obtained through cooling methods such as (1), (1), (2), and (n)+t1 in Example 3 may exceed one length.

FIG. 2 shows the fibers obtained by processing the agglomerates. The fibers are potassium hexatitanate fibers (Kg(Ti, M'')b013) obtained by firing at 1000°C after cold water treatment.
(The processing conditions correspond to [■] (3) in Example 1), and CI in the same figure) is a fiber group (magnification = × 100),
II) shows an enlarged appearance (magnification: ×3000) of a single fiber. Incidentally, an X-ray powder diffraction diagram 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 using natural rutile sand or natural anatase sand as a raw material. The manufacturing cost is about 1/6 of that when using highly purified titanium oxide as a raw material.

According to the present invention, it is possible to obtain fibers with 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, that of preprite fiber is approximately 1500°C, and that of titania fiber is approximately 1840°C.
It can be seen that it has extremely high heat resistance.

It also has excellent alkali resistance and chemical resistance that exceeds that of ashest fiber. Furthermore, potassium hexatitanate is extremely hard, with a Mohs hardness of about 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. 4 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 obtained by the present invention (
(Ti, M') 02) and (1') are rutile fibers (TiO□) obtained from highly purified titanium oxide as a raw material.
, (2) is potassium hexatitanate fiber (Kg(Ti,M')bO13) obtained by the present invention, and (2') is potassium hexatitanate fiber (K , Tia013) and (3) respectively show the thermal conductivity of the rutile-preprite-potassium hexatitanate fiber obtained by the present invention.As shown in the figure, in comparison of the same type of fiber, It can be seen that the fiber has a lower thermal conductivity, and the thermal conductivity of the three-phase composite fiber is also extremely low, indicating that it has poor thermal insulation properties.

Various fibers obtained by the method of the present invention can be used as insulation materials, fireproofing materials,
Constituent materials such as heat-resistant materials, friction materials, filtration materials, catalyst carriers for high-temperature applications, sound-absorbing materials, cement, plastics, etc.
They are useful as composite reinforcing materials for metals, etc. Crystalline titanate fibers and titania fibers also have excellent adsorption properties for ions, etc., so they can be used as constituent materials for waste disposal barrier layers in nuclear power facilities, for example. Titania fibers are suitable, and furthermore, titania fibers are useful as insulating materials, dielectric constituent materials, and the like.

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]

Fig. 1 is a graph showing an example of a temperature drop curve of a molten reaction product in the cooling solidification process, and Fig. 2 [9(1) (■]) is a microscope photograph used as a drawing showing an example of the fiber obtained by the present invention. ,
Figure 3 shows potassium hexatitanate fiber (Kz(Ti, M'
)6013), and FIG. 4 is a graph showing the thermal conductivity of various 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 or a mixture of natural rutile sand and natural anatase sand 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. Mix and heat to melt and react,
A method for producing titanium compound fibers, characterized in that in the cooling solidification step, the molten reaction product is cooled at a cooling rate of 0.7°C/sec to 25°C/sec.