JPS6046926A - Manufacture of crystalline titanate fiber - Google Patents

Abstract

PURPOSE:To produce the titled fiber having cation-exchange property and excellent heat resistance, at a low cost, by forming a fibrous material from molten mixture of rutile sand or anatase sand and K2O, and treating the fiber with an acid to extract the K component completely. CONSTITUTION:The natural rutile sand or anatase sand of formula I (M is existing impurity metal) is mixed with K2O and/or a compound forming K2O with heat (e.g. KOH, K2CO3, etc.) at a ratio of formula II (n is 1.5-2.5). The mixture is melted by heating, and a fibrous meterial composed of crystals having lamellar structure same as potassium dititanate is produced from the molten mixture. The fibrous material is treated with an aqueous solution of an acid (e.g. aqueous solution of hydrochloric acid) to extract the K component completely. A crystalline titanate fiber can be manufactured keeping the above lamellar structure. Since a natural titanium oxide is used as it is, the objective fiber can be manufactured at a low cost compared with the conventional process using a high-purity TiO2.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing crystalline titanate fibers having excellent heat resistance and cation exchange properties.

More specifically, the present invention relates to a method for producing crystalline titanate fibers using naturally produced rutile sand or anatase sand as a titanium raw material.

Conventionally, the methods for producing crystalline titanate fibers include 1) flux method, in which potassium tetratitanate (K2O
- A method for producing crystalline titanic acid (H2T:L 40q/nH2O1 fibers) by growing 4TiO2) fibers and subjecting them to depotassium treatment.

2) A mixed phase fiber of potassium tetratitanate and potassium nititanate (K2O.2T: i-0,) is grown as the primary phase using a slow cooling and firing method, and then subjected to a depotassium treatment to produce H2Ti,
O,・mH2O and H2Ti205・mH2O (however,
m is 2 or less).

3) Potassium nititanate (K2O・2TiO
Potassium niticunate fibers are grown from the low melting point melt of 2) and subjected to depotassium treatment to produce crystalline titanic acid (HJi2).
05・mH2O) (However, m is 2 or less) A method of manufacturing all fibers.

〃i known.

However, in any of these methods, the titanium raw material used is highly pure titanium dioxide, for example, titanium dioxide with a purity of 99% or more produced from ilmenite ore by the sulfuric acid method or the alkaline method. As a result, the cost of raw materials increases, making the product expensive and limiting its scope of use.A1'+7. , f (Yes, natural ruti"-'g, :: 2, which is inexpensive as a titanium raw material! Rusando or anatase sando is used as it is,
Examples provide methods for producing crystalline titanate fibers at low cost.

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) In both the flux method and the slow cooling and calcination method, potassium titanate fibers, which are the primary phase, are produced, but due to the influence of impurities contained in the titanium raw material, dense fibers are formed at the bottom of the melt. It was found that it was impossible to separate the fibers from the lumps.

2) On the other hand, in the melt method, impurities in the titanium raw material do not have any effect, but rather have a positive effect, melting in a short time,
It was found that crystalline titanate fibers could be easily obtained.

The present invention was completed based on this knowledge.

The gist of the present invention is to combine naturally produced rutile sand or anatase sand represented by the general formula (Ti, MIO□ (where M represents impurity gold 1), and oxidized by potassium oxide or heating. A potassium compound that produces potassium or a mixture thereof is expressed in the general formula 2O-n (Ti, MI02 (where n is 1.
5 to 2.5, M is the same as above), heat and melt the mixture to produce a melt, and from the melt crystals with the same layered structure as potassium nititanate (K2O 2Ti02) are produced. Naturally occurring rutile sand is obtained in the form of sand from alluvial deposits, and its composition is approximately 95%. % Tio2, as impurities Fe2O, Al2O5, cr206
．． 5in2, Nb2o5, zro2, v205, etc. are included, and the content is, for example, Feo 0.6%, 5A/20.0.4%, 0r2050.3%, 5in20
．． 6%, called Lusand). The smaller the particle size, the easier it is to handle, so a smaller particle size is preferable.

As the potassium component, potassium dioxide or a potassium compound that generates K2O upon heating, such as KO
Examples include H, K2GO, lKHcO, and the like.

Naturally produced rutile sand and potassium components are combined into K2O-n
(Ti, M)02 (where n is 1.5 to 2.51.
M represents an impurity metal (hereinafter the same applies), and a crystalline fibrous material having a side layered structure is formed.

However, if the mixing ratio of the mixture becomes smaller than n of 1.5, a layered structure cannot be obtained, and if n exceeds 2.5, the melting point becomes high; O
, potassium titanate with the composition is generated, making it impossible to separate the fibers. Therefore, it is necessary that n ranges from 1.5 to [2, preferably n is 2, and j is.

1 As a fiber forming method, 1), melt spinning method, for example, 2l is glass M! Same method as fiber molding. 2) A method of draining the melt into a separate container. 5) How to rapidly cool the bottom of Ruho.

4) Steam spraying method: A method of spraying high-pressure steam onto the melt flowing out from the ship pushing.

When formed into a fibrous form by cooling and solidifying, K2O.2(Ti
, M) 02 composition becomes a crystalline potassium titanate fibrous material having a crystallographic layered structure. He separated the fibers with water and treated them with a dilute aqueous acid solution to extract all the potassium components, resulting in crystalline titanate fibers that retained a layered structure. As the acid aqueous solution, any acid aqueous solution may be used, but hydrochloric acid aqueous solution is the most effective.
s 0onsoli-dated Lim1t6dN
s-grade) (composition, TiO2' and 2CO3 (
powder) were mixed at a molar ratio of 2:1. Approximately 6fI of this mixture was placed in a 30-℃ platinum crucible and heated to 1100℃.
A melt was obtained by heating for 30 minutes. The crucible containing this melt was placed on a water-cooled iron plate, and the bottom portion was rapidly cooled and solidified to form fibers. The fibers were separated by immersing the crucible in 17 ml of water for 2 hours. This fiber is 20j2 (Ti,
It was a crystalline substance having a composition of M I O2 (M represents an impurity). After further washing with 11 water, immersion treatment in 1 t/day of 0.5M hydrochloric acid aqueous solution was repeated twice to remove potassium. Further, the immersion treatment was repeated twice at a rate of 7 kll/day, and then air-dried. The obtained titanate fibers were bundle-like fibers with a length of 2 to 5 fins and a diameter of 0.01 to 0.2 fins.

Note that after the potassium removal treatment, the color became significantly whiter than before the treatment.

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 100% lower than in the conventional method, and inexpensive crystalline titanate fibers can be obtained. It has the effect of being used.

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Claims (1)

[Claims] 1. Naturally produced rutile sand or anatase sand represented by the general formula (Ti, M)Oz (where M represents a contained impurity metal) and potassium oxide or potassium silica oxide by heating. The resulting potassium compound or a mixture thereof is expressed in the general formula 20n(Ti;M)02 (where n is 1.5
~2.5, M is the same as above), heat and melt the mixture to produce a melt, and from the melt a crystal with the same layered structure as potassium nithimenate (K2O.2Ti02). 1. A method for producing crystalline titanate fibers, which comprises forming a fibrous material consisting of a fibrous material, and then treating the fibrous material with an acid to extract all of the potassium components in the fibrous material and replacing it with hydrogen ions.