JPH0223482B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for producing titania fiber, which is excellent as a heat-resistant material and a heat-insulating material. More specifically, the present invention relates to a method for producing titania fibers using naturally produced rutile sand or anatase sand as titanium raw materials and titanium slag produced when producing pig iron from illuminite ore.

Conventional technology Conventional methods for producing titania fibers include: (1) Using the flux method, potassium tetratitanate (K ₂ O 4TiO ₂ ) fibers are grown as the primary phase, and all of the potassium is extracted by depotassium treatment. A method of making crystalline titanate fibers and firing them to make titania fibers.

(2) A method of growing mixed phase fibers of potassium tetratitanate and potassium dititanate as the initial phase using a slow cooling and firing method, and then producing titania fibers in the same manner as in (1) above.

(3) A method in which potassium dititanate fibers are grown from a low melting point melt of potassium dititanate using a melt method, and titania fibers are then produced in the same manner as in (1) above.

It has been known.

However, in all of these methods, the titanium raw material used is highly pure titanium dioxide, for example, 99% or more high purity titanium dioxide produced from ilmenite ore by the sulfuric acid method or the chlorine method, so the raw material cost is low. The problem was that the product became expensive and its range of use was limited.

In order to solve this problem, the present inventor first investigated the applicability of conventional methods using naturally produced rutile sand or anatase sand as a titanium raw material, and found that (1) Flux method and slow cooling sintering method. It was found that although potassium tetratitanate fibers, which are the primary phase, are produced, impurities contained in the titanium raw material form a dense lump at the bottom of the crucible, making it impossible to separate the fibers.

(2) On the other hand, in the melt method, it was found that impurities in the titanium raw material had no influence, but rather had a positive influence, melted in a short time, and titania fibers could be easily obtained.

Based on this knowledge, we developed a method for manufacturing titania fibers by a melt method using titanium slag and naturally produced rutile sand or anatase sand as raw materials for the titanium component.

That is, first, the general formula (Ti, M)O ₂ (however,
Naturally produced rutile sand or anatase sand represented by (M represents a contained impurity metal) and potassium oxide or a potassium compound that produces potassium oxide by heating, or a mixture thereof,
General formula K ₂ O・n (Ti, M) O ₂ (where n is 1.5~
_2.5 .
2TiO ₂ ) is formed, and then treated with acids to extract all of the potassium components in the fiber to obtain crystalline titanate fibers, which are then heated at 500°C or higher. We have completed a method for producing titania fibers by heating at a temperature lower than the melting temperature.

Purpose of the Invention The present invention utilizes titanium slag, which is a titanium metal raw material produced when producing pig iron from illuminite ore, as it is as a raw material for titanium components, and utilizes the impurities contained therein as an active ingredient. It is an object of the present invention to provide a method for producing titania fibers having specific properties.

Structure of the Invention The present inventor conducted research to achieve the above object, and found that the composition of the titanium slag is about 85% (% represents weight %. The same applies hereinafter) of TiO ₂ , and impurities such as FeO and Fe _{2 O3 , Al2O3} , _Cr2O3 , _{SiO2 ,}
Nb ₂ O ₅ , ZrO ₂ , V ₂ O ₅ , etc. are included, and their content is the highest at about 10%, for example, if Fe is Fe ₂ O ₃ , and the other content is about 0.3 to 0.7%. Since it contains a large amount of iron impurities, if it is used alone as a titanium raw material, it is difficult to obtain crystalline titanate fibers. However, if this is mixed with naturally produced rutile sand or anatase sand within a certain range and used as a titanium raw material, crystalline titanate fibers can be produced. It has been found that titania fibers can be easily obtained by heating at a temperature lower than the above temperature, and that a material with strong mechanical strength can be obtained due to the impurity metal contained in the titanium component raw material. The present invention was completed based on this knowledge.

The gist of the present invention is to prepare a mixture of titanium slag produced during the production of pig iron from illuminite ore and naturally produced rutile sand or anatase sand in a ratio by weight of less titanium slag than 3:1, using the general formula ( Ti, M)O ₂ (where M represents a contained impurity metal), and the mixture and potassium oxide, a potassium compound that generates potassium oxide upon heating, or a mixture thereof are expressed by the general formula
K ₂ O・n (Ti, M) O ₂ (where n is 1.5 to 2.5, M
is the same as above), and then heated to produce a melt, and from the melt a fibrous material consisting of crystals with the same layered structure as potassium dititanate (K ₂ Ti ₂ O ₅ ). Titanium is formed by cooling and solidifying, and then treated with acid to extract all of the potassium components to obtain crystalline titanate fibers, and the fibers are heat-treated at a temperature of 500°C or higher and lower than the melting temperature. It's in the fiber manufacturing method.

The composition of titanium slag (hereinafter simply referred to as titanium slag) produced when producing pig iron from illuminite ore (FeTiO ₃ ) used in the present invention is as described above.

In addition, naturally occurring rutile sand is obtained in the form of sand from alluvial deposits, and its composition contains approximately 95% TiO ₂ and impurities such as Fe ₂ O ₃ , Al ₂ O ₃ , Cr ₂ O ₃ ,
It contains SiO ₂ , Nb ₂ O ₅ , ZrO ₂ , V ₂ O ₅ , etc., and its content is, for example, Fe ₂ O ₃ 0.6%, Al ₂ O ₃ 0.4%,
_{Cr2O3 0.3} %, _SiO2 0.6, _{Nb2O5 0.3} %, ZrO2 _0.7 %,
_V2O5 is 0.7% _. Naturally produced anatase sand has almost the same composition. However, since rutile sand is an abundant resource, it is preferable to use it (hereinafter referred to as rutile sand). Since the smaller the particle size, the easier the reaction is, the smaller the particle size is, the more desirable it is.

The mixing ratio of titanium slag and naturally produced rutile sand or anatase sand is required to be such that the ratio of titanium slag to rutile sand or anatase sand is less than 3:1 by weight. When the ratio exceeds 3:1 and the amount of titanium slag increases, the amount of impurity metal becomes too large, making it difficult to obtain a fibrous material consisting of crystals with the same layered structure as potassium dititanate.

The potassium component to be mixed into the titanium raw material mixture includes potassium dioxide or a compound that produces potassium dioxide upon heating, such as KOH, K ₂ CO ₃ ,
Examples include KHCO ₃ .

The titanium raw material mixture and potassium component are K ₂ O.
They are mixed at a ratio that produces n(Ti,M)O ₂ (where n is 1.5 to 2.5 and M represents an impurity metal). 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 less than 1.5, a layered structure cannot be obtained;
When is more than 2.5, not only the melting point becomes high, but also
Potassium titanate with a composition of K ₂ Ti ₄ O ₉ is generated, making fiber separation impossible. Therefore, the range of n is 1.5~
A range of 2.5 is required, preferably n is 2.

The fiber forming method is (1), melt spinning method, for example, the same method as glass fiber molding. (2) A method of draining the melt into a separate container; (3) A method of rapidly cooling the bottom of the crucible. (4) A method of spraying high-pressure steam onto the molten material flowing out from the pushing using a steam spraying method.

When formed into a fiber by cooling and solidifying, K ₂ O・2
It becomes potassium titanate having a (Mi,M)O ₂ composition, and becomes a crystalline potassium titanate fibrous material having a crystallographic layered structure. After separating the fibers with water, the fibers are treated with a dilute acid aqueous solution to extract all the potassium components, resulting in crystalline titanate fibers that maintain a layered structure. Although any acid aqueous solution may be used, a hydrochloric acid aqueous solution is most effective.

Example 1 Titanium slag (composition: TiO ₂ 85%, main impurities: Fe ₂ O ₃ 10%, SiO ₂ 2
%, MnO ₂ 1.5%, Nb ₂ O ₅ 0.2%), and rutile sand (Associated Minerals Consoli−dated
Limited NS-grade) (composition, TiO ₂ 95.6%,
_{Fe2O3 0.6} %, _ZrO2 0.7%, _SiO2 0.6%, _{Cr2O3 0.3}
%, _{V2O5 6.7} %, _{Nb2O5 0.3} %, _{Al2O3 0.4} %) particle size
A material with a diameter of 100 to 60 μm was used.

A mixture of titanium slag and rutile sand in a weight ratio of 1:1 (this composition is made up of 6.4 g of (Ti, M)O ₂ (where M represents an impurity metal) and K ₂ CO ₃
Powder in a molar ratio of 2:1 (6.5g to 5.5g),
That is, (Ti,M)O ₂ :K ₂ CO ₃ was mixed at a ratio of 2:1. Approximately 11.9 g of this mixture was placed in a 30 ml platinum crucible and heated at 1100° C. for 30 minutes to form a melt.
This crucible was allowed to cool on an iron hot plate at 120°C to solidify and form fibers.

The crucible was immersed in 1 water for 2 hours to separate the fibers. This fiber was a crystalline substance having a composition of K ₂ O.2(Ti,M)O ₂ (M represents an impurity). After further washing with 1 part of water, 0.5M hydrochloric acid aqueous solution 1 part
The immersion treatment of /day was repeated twice to obtain titanate fibers. Anatase type titania fibers were obtained by heat treating this at 700 to 1000°C for 30 minutes. The obtained fibers have a length of 2 to 5 mm and a diameter of 0.01 to
The fibers were bundles of 0.2 mm. Identification by X-ray powder diffraction revealed that it was an anatase single phase with good crystallinity.

In addition, when heat-treated at 1100℃ for 30 minutes, titania fibers containing a mixture of rutile type and anatase type become 1150℃.
After heat treatment at ℃ for 30 minutes, rutile type single phase titania fibers were obtained.

Anatase type titania fibers turn slightly grayer than titanate fibers, but are stable up to high temperatures of 1000°C. When this phase transitions to the rutile type, the fiber becomes more grayish brown than the anatase type fiber, but the fiber state remains the same. On the other hand, when titanate fibers made by the melt method using conventional high-purity TiO ₂ are phase-transformed to rutile-type titania via anatase-type titania, the fiber state cannot be maintained and almost no fibers are produced. It turns into powder.

Example 2 The same raw materials as in Example 1 were used. A mixture of titanium slag and rutile sand in a weight ratio of 1:3 (this composition is expressed as (Ti,M) _O2 ) and
K ₂ CO ₃ powder was mixed in a molar ratio of 2:1, ie (Ti,M)O ₂ :K ₂ CO ₃ =2:1. Put 11.9g of this mixture into a 30ml platinum crucible and heat it to 1100℃.
Heat for 30 minutes to melt. Thereafter, the same fiberization treatment, fiber separation treatment, depotassium treatment, and heat treatment as in Example 1 were performed.

The obtained fibers have a length of 2 to 5 mm and a diameter of 0.01 to 0.2
It was a bundle of mm. The identification results of X-ray powder diffraction were the same as in Example 1.

Example 3 Fibers were produced in the same manner as in Example 1, except that the same raw materials as in Example 1 were used and the mixing ratio of titanium slag to rutile sand was 3:1 by weight. The obtained fibers were bundles with a length of 2 to 5 mm and a diameter of 0.01 to 0.2 mm. The identification results of X-ray powder diffraction were the same as in Example 1.

Effects of the Invention According to the method of the present invention, titanium slag produced when producing pig iron from illuminite ore and naturally produced rutile sand or anatase can be mixed and used as raw materials for the titanium component, so compared to the conventional method, The raw material cost is about 1/12th, and inexpensive titania fibers can be obtained. Furthermore, due to the impurities contained in the titanium raw material, the mechanical strength is increased, and an excellent effect can be obtained not only from anatase fiber but also from rutile fiber.

Claims (1)

[Claims] 1. A mixture of titanium slag produced when producing pig iron from illuminite ore and naturally produced rutile sand or anatase sand at a weight ratio of less titanium slag than 3:1 is mixed with the general formula (Ti, M) O. ₂ (where M represents the impurity metal contained), and the mixture and potassium oxide, a potassium compound that generates potassium oxide upon heating, or a mixture thereof shall be expressed by the general formula
K ₂ O・n (Ti, M) O ₂ (where n is 1.5 to 2.5, M
is the same as above), and then heated to produce a melt, and from the melt a fibrous material consisting of crystals with the same layered structure as potassium dititanate (K ₂ Ti ₂ O ₅ ). is formed by cooling and solidifying, and then treated with acid to extract all of the potassium components to form crystalline titanate fibers, which are then heat-treated at a temperature of 500°C or higher and lower than the melting temperature. Method of manufacturing titania fiber.