JPS6125657B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing titania hydrate fibers and titania glass fibers, titania hydrate fibers, titania glass fibers, cation exchange agents, cation adsorbents, filter materials, catalysts, catalyst carriers, etc. It is useful for

It has been known that titania glass fibers can be synthesized as a sub-synthesis under special conditions during the crystal synthesis of titania or alkali metal titanates by hydrothermal methods using high-pressure vessels, flux methods, solid phase reactions, etc. It is being However, the amount obtained by these methods ranges from several microns to several hundred microns.
It has the drawback that it is difficult to produce industrially because it is made of fibers with a certain length and can only be obtained in small quantities.

The present invention aims to improve this drawback, and its purpose is to provide a manufacturing method that does not require a high-pressure container or flux, is easy to produce industrially, and can obtain fibers with a long fiber length. .

As a result of research to achieve the above object, the present inventors found that the general formula M ₂ O component nTiO ₂ (where M is Na,
K, Rb, or Cs; n represents 1 to 5; ) or a raw material for the alkali metal titanate, such as a mixture of titanium oxide and an alkali metal compound, is heated to its melting temperature to form a melt, and the melt is rapidly cooled and allowed to stand. Crystallized fibers with an average length of about 5 mm can be obtained by cooling, slow cooling, or a combination thereof. Also,
When the crystalline fibrous material is treated with a mineral acid or an organic acid, the M ₂ O component is extracted, and it can be converted into a titania hydrate fiber by changing it to one with a composition of TiO ₂ .nH ₂ O. The present invention was completed based on the finding that titania glass fibers can be easily obtained by subjecting fibrous materials to heat dehydration treatment at temperatures below 250°C.

The titanium oxide used in the method of the present invention is preferably anatase type titanium oxide, which has good reactivity, and the particle size is preferably fine to facilitate reaction with alkali metal components. In addition to titanium oxide, a titanium compound that produces titanium oxide may be used as a raw material.

The alkali metal oxides used in the method of the present invention include K ₂ O, Na ₂ O, Rb ₂ O, Cs ₂ O, etc., and the alkali metal compounds that produce the oxides, such as KOH, NaOH, RbOH. ,CsOH,
_{K2CO3 , NaCO3} , _{Rb2CO3 , Cs2CO3 , KHCO3} ,
_NaHCO3 , _RbHCO3 , _CsHCO3 , _KNO3 ,
NaNO ₃ , RbNO ₃ , CoNO ₃ , etc. may also be used as raw materials.

The above raw materials are mixed with M ₂ O component nTiO ₂ (however,
When they are blended and melted at a ratio that produces 0<n<5), they react to produce alkali metal titanate.
Note that the alkali metal titanate may be produced not only by this method but also by other methods.

The obtained alkali metal titanate or its raw material mixture is heated as it is or mixed with a viscosity modifier, a binder agent such as an alkali metal borate, etc. to facilitate fiber forming, and heated to a temperature equal to or higher than their melting point. A melt is produced, and a fibrous material is produced from the melt. As a fiber forming method, simply cooling the melt can crystallize it into fibers due to the relatively large amount of alkali metal components, and for example, the melt can be poured into a metal container with a cooled bottom. It is obtained by letting it solidify. Further, it can be easily obtained by a general glass long fiber forming method or a short fiber forming method using a steam blowing method in which high pressure steam is sprayed onto the melt flowing out from pushing. When fiber formation is performed by simply cooling the melt, a lump of fibers is obtained, but if the unreacted M ₂ O component is washed away by immersing it in water, it can be separated as a fibrous material. It will be done.

The fibrous product is then extracted with a mineral or organic acid, preferably an aqueous solution of hydrochloric acid, to extract the alkali metal components.

If this extraction is carried out too quickly, the alkali metal component will be extracted only from the surface portion, and the alkali metal component from the core portion will not be sufficiently removed. Therefore, it is desirable to soak for a certain amount of time.

A dilute aqueous acid solution may be used after being heated to a temperature below its boiling point. Furthermore, in order to increase the extraction effect, operations such as stirring and circulation may be performed.
The dilute acid aqueous solution may be either an inorganic acid or an organic acid, but it is desirable to use one that does not impure the product. The extraction ratio is such that the composition of the fibrous material is TiO ₂ ·nH ₂ O · (0<n≦5).

By extracting alkali metal components
Titanium hydrate fibers having a TiO ₂ .nH ₂ O composition are obtained. This titania hydrate fiber retains the original alkali metal titanate structure and is a crystalline intermediate phase with a structure in which alkali metal ions are replaced with H ⁺ or H ₃ O ⁺ ions, and it swells and dehydrates. Has characteristic ion exchange properties.

Next, the obtained titania hydrate fiber was heated at 250°C.
Titanium glass fibers can be obtained by heating and dehydrating at the following temperatures. Naturally, the temperature of this heating and dehydration treatment must be below 250°C, which is the stable range of titanium glass.

This fiber has excellent ion adsorption properties for polyvalent cations, liquid or gas cleaning properties, and is also effective as a catalyst and a carrier for the catalyst.

Furthermore, when the obtained titania hydrate fiber or titania glass fiber is heated within a temperature range of more than 250°C and less than 1200°C, anatase type or rutile type crystalline titania fiber can be obtained. heating temperature
Anatase-type crystalline titania fibers are produced in the temperature range exceeding 250℃ and below 900℃;
In the temperature range below 1200°C, rutile-type crystalline titania fibers are formed. This fiber is the adsorbent mentioned above,
In addition to being used as a superagent, catalyst, or catalyst carrier, it is useful as an insulating material and a heat-resistant/insulating material with a melting point of 1840°C.

Example 1 TiO ₂ .K ₂ CO ₃ powders were mixed at a molar ratio of 2:1. About 45 g of the mixture was filled into a 100 ml platinum crucible and melted by heating at 1100° C. for about 30 minutes. The melt was poured into a 200 ml metal container whose bottom was cooled with water and quenched to crystallize into fibers. What was obtained was a fibrous aggregate with an average length of 5 mm. This was immersed in water for about 1 hour to wash off the residual K ₂ O component, and the fibrous material was separated. In this case, applying compressive stress to the aggregate in a direction perpendicular to the fiber axis promotes separation of the fibrous material.

The separated fibrous materials were bundles with a diameter of 0.1 to 0.5 mm and an average length of about 5 mm. Under a polarizing microscope, it was a crystalline material with strong interference color and direct extinction in the direction of elongation. The powder X-ray diffraction diagram using Cu Kα as the anticathode shows only broad peaks around 20=11°, 29°, and 48°, indicating that the fiber has extremely poor crystallinity. When this was heated to 900°C to improve crystallization, it was found that it consisted of two phases: a K ₂ Ti ₄ O ₉ phase and a Chichi phase (possibly a K ₂ T ₂ O ₅ phase).

Next, the obtained fibrous material was dissolved in a 1N-HCl aqueous solution.
The fibers were immersed at a ratio of 10 g per 100 ml, and the K ₂ O component was extracted while stirring for about 1 hour, followed by washing with water and air drying to obtain titania hydrate fibers. The powder X-ray diffraction pattern of the titania hydrate is 2θ〕10゜, 25.6゜,
It was a crystalline fiber exhibiting a broad peak around 48.6°.

In addition, instead of draining the melt into a separate container, the bottom of the receptacle taken out was quenched with water to produce a fibrous material, which was then treated in the same manner as above. Also,
After melting, the power to the furnace was turned off, and a cooling material was brought into contact with the bottom of the crucible in the furnace to form a fibrous material, which was then treated in the same manner as described above. A similar titania hydrate fiber was obtained. Furthermore, even if the lump obtained by quenching the melt is directly treated with 1N HCl aqueous solution without water treatment, and the fiber separation and _K2O component extraction are performed simultaneously, the same titanium hydrate can be obtained. Fibers were obtained.

Example 2 The titania hydrate fiber obtained by the method of Example 1 was
Titanium glass fibers were obtained by heating and dehydrating at 100 to 250°C. The powder X-ray diffraction pattern of the titania glass fiber showed no diffraction peaks.

Example 3 The melt produced by the method of Example 1 was discharged from a pushing and was blown with high pressure air to form fibers. The scattered matter is an aggregate of bundled fibers, and this aggregate can be separated into finer fibers by treating with water in the same manner as in Example 1. The composition of the obtained fiber was investigated by heat treatment at 900°C, and it was found to be a mixed phase of K ₂ Ti ₄ O ₉ phase and an unknown phase (possibly K ₂ Ti ₂ O ₅ ).

Next, the obtained fibrous material was treated in the same manner as in Example 1 using a 1N HCl aqueous solution to obtain titania hydrate fibers.

Next, by the same treatment as in Example 2, titania glass fibers were added, and further the titania glass fibers were
Anatase type titania fibers could be obtained by heat treatment at ℃.

As described above, according to the present invention, titania hydrate fibers and titania glass fibers, which have conventionally been difficult to obtain with long fiber lengths and are difficult to produce industrially, can be produced in large quantities without the need for complicated equipment. It is easy to produce, and long fiber products can also be easily obtained, providing excellent effects.

Claims (1)

[Claims] 1 General formula M ₂ O・nTiO ₂ (where M is Na, K,
An alkali metal titanate represented by Rb or Cs (n represents 1 to 5) or a raw material mixture of the alkali metal titanate is heated above its melting temperature to form a melt, and the melt is cooled. A crystalline fibrous material is formed in the process, and then the obtained fibrous material is treated with a mineral acid or an organic acid to form M ₂ O.
The components are extracted and TiO ₂・nH ₂ O (0<n≦
5) A method for producing a titania hydrate fiber, which is characterized in that the titania hydrate fiber has the composition. 2 General formula M ₂ O・nTiO ₂ (M is Na, K,
An alkali metal titanate represented by Rb or Cs (n represents 1 to 5) or a raw material mixture of the alkali metal titanate is heated above its melting temperature to form a melt, and the melt is cooled. A crystalline fibrous state is formed in the process, and then the obtained fibrous material is treated with mineral acid or organic acid to form M ₂ O.
The components are extracted and TiO ₂・nH ₂ O (0<n≦
A titanium hydrate fiber having the composition of 5) is used.
A method for producing titania glass fiber, which is characterized by heat dehydration treatment at a temperature of 250°C or less.