JPH0159214B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for producing potassium hexatitanate fibers having excellent properties of heat resistance, heat insulation, chemical resistance and reinforcing properties, and composite fibers thereof. More specifically, the present invention relates to a method for producing potassium hexatitanate fibers or composite fibers thereof using a mixture of titanium slag produced when producing pig iron from natural rutile sand or anatase sand ore and illuminite ore as a titanium raw material.

Prior Art The conventional method for producing potassium hexatitanate fibers uses a titanium component raw material and a potassium oxide raw material: (1) growing potassium tetratitanate fibers as a primary phase in a melt using flux; A method for producing potassium hexatitanate fibers by performing a depotassium treatment to remove a portion of potassium and a heat treatment.

(2) A decomposition process in which a mixed phase fiber of potassium tetratitanate and potassium dititanate is created as the initial phase by utilizing the decomposition-melting-association reaction of potassium tetratitanate without using flux, and part of the potassium is removed. A method for producing potassium hexatitanate fibers by performing potassium treatment and heat treatment.

(3) Potassium dititanate fibers are grown using the low melting point harmonic melting of potassium dititanate fibers, and potassium hexatitanate fibers are produced by performing potassium removal treatment to remove part of the potassium and heat treatment. method is known.

However, in all of these methods, the raw material, titanium dioxide, is produced from illuminite ore using the sulfuric acid method or the chlorine method and has a purity of over 99%, which increases the raw material cost. The drawback was that the product was expensive.

In order to solve this problem, the present inventor first investigated the applicability of the conventional method using naturally produced rutile sand or anatase sand as a raw material for the titanium component, and found that (1) Flux method and slow calcination. In this method, both are formed in potassium tetratitanate fibers, which are the primary phase, but it was found that due to the influence of impurities contained in the titanium raw material, a dense lump formed 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 had a positive influence, melted in a short time, and easily obtained potassium hexatitanate fibers.

Based on this knowledge, we first developed a method for producing potassium hexatitanate fibers using the melt method using naturally produced rutile sand or anatase sand as titanium raw materials, and a method for producing potassium hexatitanate composite fibers. did.

That is, naturally occurring rutile sand or anatase sand represented by the general formula (Ti, M)O ₂ (where M represents the impurity metal contained), potassium oxide or a potassium compound that generates potassium oxide by heating, or these. The mixture has 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), the mixture is heated and melted to produce a melt, and potassium dititanate (K ₂ O.2TiO ₂ ) is extracted from the melt.
A fibrous material consisting of crystals with the same layered structure as K ₂ (Ti, M) ₆ O ₁₃ (However,
M is the same as above), and a method for producing potassium hexatitanate fibers or potassium hexatitanate composite fibers was completed by heating this to a temperature of 800°C or higher and 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, and naturally produced rutile sand or anatase sand as raw materials for titanium components, and contains them as raw materials for titanium components. The purpose of the present invention is to provide a method for producing potassium hexatitanate fibers or potassium hexatitanate composite fibers having excellent properties at low cost by utilizing the impurities contained in these materials as active ingredients.

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 , Y 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, it is difficult to obtain potassium hexatitanate fibers if it is used alone as a titanium raw material. However, if this is mixed with naturally produced rutile sand or anatase sand within a certain range and used as a titanium raw material, and manufactured by the melt method, the impurities contained in the titanium raw material will not have an effect, but rather have a positive effect. It was found that potassium hexatitanate fibers or potassium hexatitanate composite fibers could be easily obtained by melting in a short time. The present invention was completed based on this knowledge.

The gist of the present invention is to prepare a mixture of titanium slag produced when producing 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. ,
M) O ₂ (M represents the impurity metal contained)
The mixture and potassium oxide, a potassium compound that generates potassium oxide upon heating, or a mixture thereof are represented 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) is mixed in the proportion shown, heated to form a melt, and from the melt potassium dititanate (K ₂ A fibrous material consisting of crystals with the same layered structure as Ti ₂ O ₅ ) is formed by cooling and solidifying, and then treated with water to form K ₂ (Ti, M) ₆ O ₁₃ (where M is the same as above).
A method for producing potassium hexatitanate fibers or potassium hexatitanate composite fibers is characterized in that the fibers are heated at a temperature of 800° C. or higher but lower than the melting temperature to form a tunnel structure.

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
%, V ₂ O ₅ 0.7%. Naturally produced anatase sand has almost the same composition. However, since rutile sand is an abundant resource, its use is preferred. 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. If the ratio exceeds 3:1 and the amount of titanium slag increases, impurities will be too large and it will be 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 KHO, 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 molten material into a separate container. (3), 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 fibrous form by cooling and solidifying, K ₂ O・2
(Ti, M) O ₂ (where M is the same as above) becomes a potassium titanate fiber, and becomes a crystalline potassium titanate fiber having a crystallographic layered structure.
This is treated with water to give K ₂ (Ti, M) ₆ O ₁₃ . That is, a part of the K ₂ O component in the fiber is extracted by treatment with water to obtain a composition of K ₂ O.6TiO ₂ containing impurity M.

This water treatment is done with cold water, hot water, or boiling water. In general, treatment with cold water yields potassium hexatitanate single-phase fibers, and treatment with hot or boiling water yields potassium hexatitanate composite fibers. After eluting a portion of the potassium component, heating at a temperature lower than the melting temperature of 800°C or higher transforms the layered structure into a tunnel structure, resulting in a fiber with good crystallinity of potassium hexatitanate. The heating temperature needs to be lower than the melting temperature, and is preferably about 1000°C.

In the starting material composition, as the weight mixing ratio of titanium slag to rutile sand increases from 1:1 to 3:1 and the proportion of titanium slag increases, as the iron content increases, the predelite phase (K ₂ M ₂ 〓Ti ₆ O ₁₆ )
(M is mainly Fe) is mixed. This indicates that the pridelite phase is more likely to be formed when the iron content of impurities increases. Pridelite-potassium hexatitanate composite fiber has particularly low thermal conductivity,
It has excellent heat resistance and insulation properties. (Special request 1982)
(Refer to No. 142785) When the mixing ratio of titanium slag is less than 1:1, a composite fiber of pridelite-potassium hexatitanate-rutile is obtained. The heating temperature in this case is preferably 1100°C.

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 Consolidated
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 the titanium slag and rutile sand in a weight ratio of 1:1 (this composition is a molar ratio of 6.4 g of (Ti, M)O ₂ (where M represents an impure metal) and K ₂ CO ₃ powder) They were mixed in a ratio of 2:1 (6.5 g to 5.5 g), i.e. (Ti, M)O ₂ :K ₂ CO ₃ = 2:1. Approximately 11.9 g of this mixture was placed in a 30 ml platinum crucible and heated at 1100°C. The crucible was heated for 30 minutes to form a molten material.The crucible was allowed to cool on a steel hot plate at 120°C to solidify and form a fiber.
It was a crystal with a composition of K ₂ O.2(Ti, M) O ₂ (M is an impurity metal mainly composed of Fe). Crucible 1
The fibers are separated by immersion in cold water, and the fibers are further
Depotassium treatment was carried out by repeating the treatment twice with H ₂ O/10 g for 12 hours. Next, it was dried at 120°C and then treated at 1000°C for 1 hour to produce fibers. The obtained fibers had a length of 2 to 5 mm and a diameter of 0.01 to 0.2 mm. This was identified by X-ray powder diffraction and was found to be well-crystalline potassium hexatitanate.

Example 2 The same raw materials as in Example 1 were used, and a mixture of titanium slag and rutile sand was used in a weight ratio of 1:3.

Thereafter, fibers were produced in the same manner as in Example 1. The obtained fibers were bundles with a length of 2 to 5 mm and a diameter of 0.01 to 0.2 mm. This was identified by X-ray powder diffraction and was found to be potassium hexatitanate with good crystallinity.

Example 3 The same raw materials as in Example 1 were used, and a mixture of titanium slag and rutile sand in a weight ratio of 3:1 was used. Thereafter, fibers were produced in the same manner as in Example 1. The obtained fibers have a length of 1 to 2 mm and a diameter of 0.01 to
It was a bundle of 0.1 mm. This was identified by X-ray powder diffraction and was found to be a mixed phase composite fiber of potassium hexatitanate with good crystallinity and some pridellite (K ₂ M ₂ 〓Ti ₆ O ₁₆ ). This is presumed to be because as the amount of titanium slag increases, the iron content also increases, making it easier for the pridelite phase to be generated.

Example 4 The same raw materials as in Example 1 were used, and a mixture of titanium slag and rutile sand was used in a weight ratio of 1:1. It was placed in a crucible in the same manner as in Example 1 to produce a K ₂ O.2(Ti,M)O ₂ crystal fiber. The fibers were separated by soaking the crucible in 1 warm water for 2 hours, and the fibers were washed with 1 water. then 1
The sample was immersed in boiling water for 1 hour to remove part of the potassium, washed with water, and dried at 120°C. dried food
Heat treatment was performed at 1100°C for 1 hour. The obtained fibers were bundles with a length of 2 to 3 mm and a diameter of 0.01 to 0.2 mm.
This was identified by X-ray powder diffraction and was found to be a composite fiber of pridelite-potassium hexatitanate with good crystallinity. This composite fiber has particularly low thermal conductivity and excellent heat insulation properties. The thermal conductivity of the sintered body prepared by powdering the composite phase fiber at room temperature was 0.025 (W·Cm ⁻¹ ·K ⁻¹ ).

The ratio of each phase in this mixed phase changes depending on the mixing ratio of titanium slag and rutile sand, the amount of impurities contained therein, and the amount of potassium carbonate.
If the raw material composition is the same, it is possible to maintain a constant ratio by controlling the depotassium treatment. Note that a composite fiber can be produced in the same manner when naturally produced anatase sand is used instead of naturally produced rutile sand.

Example 5 The same raw materials as in Example 1 were used, and a mixture of titanium slag and rutile sand was used in a weight ratio of 1:3. Thereafter, fibers were produced in the same manner as in Example 4. The obtained fibers have a length of 2 to 5 mm and a diameter of
They were bundles of 0.01 to 0.2 mm. As a result of identifying this by X-ray powder diffraction method, it was found to be a composite fiber of pridelite-potassium hexatitanate-rutile with good crystallinity.

It is presumed that the rutile phase was formed because the amount of titanium slag mixed was small, so the iron component contained in it was reduced, and as a result, the formation of the pridelite phase was also reduced, resulting in the formation of the rutile phase. Since the rutile phase has high heat resistance (melting point 1840° C.), the Pridelite-hexatitanium potassium-rutile composite fiber has excellent heat insulation properties. The thermal conductivity of a sintered body made from powdered composite fibers at room temperature is 0.035.
(W・Cm ^-1・K ^-1 ).

Example 6 The same raw materials as in Example 1 were used, and a mixture of titanium slag and rutile sand was used in a weight ratio of 3:1.

Thereafter, fibers were produced in the same manner as in Example 4. The obtained fibers were bundles with a length of 1 to 2 mm and a diameter of 0.01 to 0.1 mm. As a result of identifying this by X-ray powder diffraction, it was found to be a composite fiber of pridelite-potassium hexatitanate with good crystallinity.

Effects of the Invention According to the method of the present invention, titanium slag produced when producing pig iron from illuminite ore is used as a natural material, without using high-purity titanium raw materials as in the case of producing conventional potassium hexatitanate fibers. Since it is used as a titanium raw material together with produced rutile sand or natural anatase sand, the raw material cost can be reduced to about 1/12.

In addition, by utilizing impurities contained in the titanium raw material as an active ingredient, potassium hexatitanate composite fibers having better heat resistance and heat insulation properties can be formed, and excellent effects can be obtained.

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 in a ratio by weight of less titanium slag than 3:1 is prepared by 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 by 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 ) is formed by cooling and solidifying, and then treated with water to form K ₂ (Ti, M) ₆ O ₁₃ (where M is the same as above), which is then heated at a temperature of 800°C or higher and lower than the melting temperature to form a tunnel structure. A method for producing potassium hexatitanate fiber or potassium hexatitanate composite fiber, characterized by: 2. The manufacturing method according to claim 1, wherein the potassium hexatitanate conjugate fiber is a potassium hexatitanate-pridellite conjugate fiber or a pridellite-potassium hexatitanate-rutile conjugate fiber.