JPS6051615A - Production of potassium hexatitanate fiber - Google Patents

Abstract

PURPOSE:To produce potassium hexatitanate fiber having superior heat resistance, heat insulating property, and chemical resistance inexpensively by utilizing naturally produced rutile sand as feed material for titanium as it is basing on the melt process. CONSTITUTION:(A) Potassium oxide (any compd. producing K2O by oxidation may be used also) was mixed with (B) 1.5-2 times mole naturally produced rutile sand (or anatase)(Ti, M)O2 (where M is metal impurity such as Al, Cr, etc.), and obtd. mixture was melted at ca. 1,100 deg.C, and the melt was drawn to fiber and solidified by cooling. Produced fibrous crystalline potassium titanate K2O.2(Ti, M)O2 having laminar structure is extracted with water to remove a part of K2O component to obtain K2(Ti, M)6O13, which is heated thereafter at >=800 deg.C. Thus, the laminar structure is transformed to tunnel structure forming potassium hexatitanate fiber.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing potassium hexatitanate fibers with excellent heat resistance, heat insulation, chemical resistance, and reinforcing properties. The present invention relates to a method for producing potassium hexatitanate fibers.

Conventionally, the method for producing potassium hexatitanate fibers is as follows: 1) Using flux, potassium tetratitanate fibers are grown as an initial phase in a melt, and potassium hexatitanate is removed by depotassium treatment and heat treatment. A method of producing fibers.

i) 1. Without using flux, by using the decomposition melting-association reaction of potassium titanate, the primary phase is formed to create a mixed phase fiber of potassium tetratitanate and potassium nititanate, and the fiber is depotassium treated and heated. A slow cooling and firing method that produces hexatitanic acid fibers through processing.

3) A melt method is known in which potassium nititanate fibers are grown using harmonic melting with a low melting point of potassium nithimenate, and potassium hexatitanate fibers are produced by performing potassium removal treatment and heat treatment.

However, in all of these methods, the raw material, titanium dioxide, is made from ilmenite ore using the sulfuric acid method or the chlorine method, which has a high purity of over 99%.
As a result, the cost of raw materials is high, the product is expensive, and the scope of its use is limited.

The purpose of the present invention is to solve this problem, and it is a method for producing potassium hexatitanate fiber at low cost by using inexpensive naturally produced rutile sand or anatase sand as a raw material for titanium. is to provide.

In order to achieve the above object, the present inventor investigated the applicability of the conventional method using naturally produced rutile sand or anatase sand as a titanium raw material. As a result: 1) A first for the flux method and slow cooling and firing method.

Potassium tetratitanate fibers, which are the main phase, are produced in both cases, but due to the influence of impurities contained in the titanium raw material, they form a dense lump at the bottom of the melting tube, making it impossible to separate the fibers.

2λ1 On the other hand, it was found that in the melt method, impurities in the titanium raw material have no influence, but rather have a positive influence, melt in a short time, and easily obtain potassium hexatitanate fibers.

The present invention was completed based on this knowledge.

The gist of the present invention is to produce naturally occurring rutile sand or anatase sand represented by the general formula (Ti, M)02 (where M represents a contained impurity metal) and potassium oxide or potassium siloxide by heating. A potassium compound or a mixture thereof is expressed in the general formula 2O-n(Ti,M)02 (where n is 1.5
~2.5, M is the same as above),
The mixture is heated and melted to produce a melt, from which a fibrous material consisting of crystals with the same layered structure as potassium nititanate (K2O.2TiO2) is formed, and then treated with water. Ti, M) 6015 fx L,
The present invention provides a method for producing potassium hexatitanate fibers, which is characterized by heating the fibers at 800° C. or higher to form a tunnel structure.

The naturally occurring rutile sand used in the present invention is obtained in the form of sand from alluvial deposits, and its composition is approximately 95% TiO.
2, and as impurities Fe2O,,Al,O,,0
r20. ．． 5in3, Nb2O5, zr02, ■205
The content is, for example, Fe2O,0,6
%, Al5O12.4%, (3r20.0.3%, 5i
n20.6%, Wb20.0.3%, Zr020.7%
, 72050.7%.

Naturally produced anatase sand has a similar composition to tti.

However, since rutile sand is an abundant resource, its use is preferred. (Hereinafter, it will be referred to as rutile sand.) Since the smaller the particle size, the easier it is to react, a small particle size is desirable.

, the potassium component includes potassium dioxide, and potassium compounds that generate K2O when heated, such as KO
Examples include H, K2CO2, KHOO, and the like.

Naturally produced rutile sand and potassium components are combined into K2O-n
(Ti-M)02 (where n is 1.5 to 2.5,
M represents an impurity metal (hereinafter the same applies). This mixture melts at about 1100°C to form a melt. When the melt is cooled and solidified, a crystalline fibrous material having a layered structure is formed.

However, if the mixing ratio of the mixture is smaller than 1.5, a layered structure cannot be obtained, and if n exceeds 2.5, not only will the melting point become high, but also K2Ti, O,
Potassium titanate of the composition is generated and fiber separation becomes impossible. Therefore, it is necessary that n be in the range of 1.5 to 2.5, preferably n be 2.

The fiber forming method is as follows: 1) Melt spinning method, for example, the same method as glass fiber molding. 2) A method of draining the melt into a separate container. 5) Method of rapidly cooling the bottom of the crucible. 4) A method of blowing high-pressure steam onto the molten material flowing out from the bushing using a steam blowing method.

When formed into a fibrous form by cooling assimilation, K2O.2(T'
i, M)02 (where M is the same as above), and becomes a crystalline potassium titanate fiber having a crystallographic layered structure. Treat this with water and
(Ti, M), O, . That is, some of the 20 components in the fiber are extracted by treatment with water, and impurities (M
) and has a composition of 20.6TiO2. The obtained product is heated to 800°C or higher.

This heat treatment transforms the layered structure into a tunnel structure, resulting in fibers of large potassium titanate with good crystallinity. The heat treatment temperature needs to be lower than the melting temperature, and the preferred temperature is about 1000°C.

Examples Rutile Sand (As5ociat, ed. Minera
ls 0onsoli-dated Limlted NS-grade) (Composition Tie29.51.6
%, Fe2O, 0.6%, ZrO20.7%, 5i0
2o, 16%, 0r20.0.3%, 72056.7%
, Nb2050.3%S, 8120.0.4%) with a particle size of 100 to 60 μm, and K2CO2 (powder),
They were mixed at a molar ratio of 2:1. Approximately 62 kg of this mixture was placed in a 30-cm platinum crucible and heated at 1100°C for 30 minutes to obtain a melt. The crucible containing this melt,
It was placed on a water-cooled iron plate and the bottom was rapidly solidified to form fibers. This fiber was a crystalline substance with a composition of 20.2(Ti,M)02 (M represents an impurity). Rutsuho 17
The fibers with a composition of 2 (Ti, M) 60.3 were immersed in water for 2 hours and separated. Further wash with 1/1 water, 120
Dry at ℃. The dried product was heat-treated at 1000°C for 3 hours.

The obtained fibers have a length of 2-5 m and a diameter of 0.01-0.
It was 211,111 bundled fibers. Identification by X-ray powder diffraction revealed that it was a single phase of potassium hexatitanate with good crystallinity.

According to the method of the present invention, naturally produced rutile sand can be used as it is as a raw material for the titanium component, and the cost of the raw material is about 1/10 of that of the conventional method, and it is an inexpensive crystalline potassium hexatitanate. It has the effect of producing fibers.

” ””,,-1 Patent applicant: Science and Technology Agency, Inorganic Materials Research Institute Director, I'R
Yu Goto,;j,),,:)

Claims (1)

[Claims] Naturally produced rutile sand or anatase sand represented by the general formula (Ti, M)02 (where M represents the impurity metal contained) and potassium oxide or a potassium compound that produces potassium oxide by heating, or a mixture thereof. , the general formula is 20.H(Ti, M) 02
(However, n is 1.5 to 2.5, M is the same as 1 as above), these mixtures are heated and heated to produce a melt, and from the melt potassium nititanate (K2O・
2TiO2), and then treated with water to form K2(Ti,M)
601. A method for producing potassium hexatitanate fiber, which comprises heating the fiber to a temperature of 800° C. or higher to form a tunnel structure.