JPS62226896A - Production of long fibrous alkali metal salt of titanic acid - Google Patents

Abstract

PURPOSE:To obtain a long fibrous alkali metal salt of a titanic acid which has a large aspect ratio and high mechanical strength such as bending strength and tensile strength by calcining a mixture composed of a titanium source compd., oxygen-contg. alkali metal compd. and a slight amt. of oxygen-contg. iron compd. in a specific temp. range. CONSTITUTION:The mixture composed of the titanium source compd., oxygen- contg. alkali metal compd. and a slight amt. of the oxygen-contg. iron compd. is calcined in a temp. range of about 900-1,350 deg.C. The mixing ratio of the titanium source compd. and the oxygen-contg. alkali metal compd. is preferably 4.0-2.2 molar ratio of TiO2/M2O (M is an alkali metal) and the ratio of the oxygen-contg. iron compd. to be added is preferably not in excess of 0.4 molar ratio of Fe2O3/TiO2. The nitrate of an alkali metal is particularly preferable as the oxygen-contg. alkali metal compd. The oxygen-contg. iron compd. is exemplified by the nitrate, sulfate, chloride, oxide, hydroxide, etc., of iron. The titanium source compd. is exemplified by titanium oxide, rutile ore, titanium hydroxide wet cake, hydrous titania, etc.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a method for producing a long fibrous alkali metal titanate, and more specifically, a method for producing alkali hexatitanate and alkali octatitanate crystals. Regarding manufacturing methods. The long fibers of these compounds not only have excellent mechanical properties such as high bending strength, but also have nine characteristics such as high electrical insulation, thermal and chemical stability, and negative thermal conductivity and temperature coefficient characteristics. It is a material that has been prepared. Therefore, it is widely used in applications such as plastic reinforcement materials, aluminum materials, battery diaphragms, thermal insulation structural materials, filtration materials, and pigments.

(Prior Art) Various methods have already been proposed for producing fibrous alkali metal titanates. Namely, the sintering method, the melting method, the hydrothermal method, the 7 lux method, the melting method, etc. are known. Generally, in any of the methods, titanium oxide and a basic oxygen-containing alkali metal compound are often used as raw materials.

Recently, fibrous alkali metal titanates have been expected to be used as a substitute for asbestos, but the currently available fibrous alkali metal titanates have a smaller aspect ratio than asbestos and are not practical enough to replace asbestos. The current situation is that this is not the case.

Japanese Patent Publication No. 42-27264 discloses titanium sources such as hydrated titania, anatase T i O2, pigments, electronic material powders, catalysts, etc. in a commercially available sulfate method.
: products, well-purified anatase pigment, ground rutile to stone and commercially available ilmenite, etc. are disclosed. Furthermore, as basic oxygen-containing alkali metal compounds, alkali metal hydroxides, alkali metal carbonates, and the like are disclosed. The above-mentioned Japanese Patent Publication No. 42-27264 discloses that a non-liquid mixture of the titanium source and a basic oxygen-containing alkali metal compound is
Calcined at 1150°C to synthesize fine alkali metal titanates, which are rich in colloidal forms with a particle size of 0.005 to 0.1 micron and a quality of at least 10 times the diameter. 2O0~850°C when manufacturing
(2) When producing a pigment rich in particle size with a diameter of 0.1 to 0.6 microns and a length of 10 to 100 times the diameter, firing at 850 to 975°C; Diameter is 0
．． 975 when producing highly insulated particles with a particle size of 6 to 3 microns and a length of 100 to 100 times the diameter.
It is described that a desired fibrous alkali metal titanate can be obtained by firing at a temperature of ~1150°C. Also disclosed is a manufacturing method in which an alkali metal halide is added to a non-liquid mixture of raw materials and fired.

However, it is difficult to separate the target material that has grown as fibers during firing, and due to the loss of fibers during the removal process, the #a fibers of the obtained fibrous alkali metal titanate are substantially 1.
It was 0 to 20 μm, and the 7 spectral ratio was around 50, which was not fully satisfactory, and its industrial use was extremely limited.

(Problems to be Solved by the Invention) The object of the present invention is to create a long-fibrous alkali metal titanate salt that can be easily separated from the ammonium nodules produced by firing and that prevents the fibers from breaking during the removal process. ? The goal is to provide the L method.

Another object of the present invention is to provide a method for producing a long fibrous alkali metal titanate having a large aspect ratio and high mechanical strength such as bending strength and tensile strength.

(Means for Solving the Problems) The present invention provides a mixture of a titanium source compound, an oxygen-containing alkali metal compound, and a total amount of an oxygen-containing iron compound of about 900 to 135%
The present invention relates to a method for producing a long fibrous alkali titanate group 17F salt, which is characterized in that it is fired in a temperature range of 0'(:').

The titanium source compound of the present invention is a compound substantially containing T i O2, and examples thereof include titanium oxide, rutile ore, titanium hydroxide web cake, and hydrous titania. The particle shape is preferably as fine as possible. For example, for titanium oxide, it is preferable to use anatase type fine particles, and for rutile and stone, it is preferable to use so-called "jet pulverized products" in which particles are pulverized by collision at high speed. The particle size is suitably in the range of 200 to 425 mesh.

The oxygen-containing alkali metal compound used in the present invention is a compound that generates M2O (M is an alkali metal) during firing, such as potassium, sodium, cesium, rubidium oxides, hydroxides, carbonates, bicarbonates, ( I! acid salts, nitrates, etc. Examples of such compounds include 2O, KOH1K2Co, KIICOJ, and 2C2.
O,,KNOj.

Na2O, NuOH1Na2Co, NaHCO),
Na=C2O-1N n N O3, C! ;2O. C3
OH1Cs2 C0-1 (SII CO3, Cs2
C2(') + s CS N Ov, R132O, R
1)0H1Rb2CO-1RbllCO,, R132C
Examples include 2O Rb N O3.

Among these, alkali metal nitrates are particularly preferred.

In the present invention, examples of the oxygen-containing iron compound include iron nitrates, sulfates, chlorides, oxides, and hydroxides.

Mixing ratio of titanium source compound and oxygen-containing alkali metal compound
The molar ratio in terms of gold M) is preferably in the range of 4.0 to 2.2. It is also necessary to add a small amount of oxygen-containing iron compound, but the amount added is F ez O3 / T i
It is preferable that the molar ratio in terms of O2 does not exceed 0.4.

In the present invention, the titanium source compound, oxygen-containing alkali metal compound, and oxygen-containing iron compound may be mixed at the time of three weighings (
Alternatively, the remaining components may be added to the mixture of the two and mixed. Each raw material may be mixed as it is, or may be made into a slurry by adding water and then spray-dried. The 14 manufacturing methods for the raw material mixture are not limited to the above, but the raw material mixture obtained by spray drying the slurry raw material has an oxygen-containing alkali metal uniformly and finely distributed on the particle surface of the titanium source compound. The granules are particularly preferred because they have extremely high reactivity.

In the present invention, these mixed raw materials are about 900 to 135
Fibrillated alkali metal titanate is obtained by firing at a temperature of 0°C.

The present invention exhibits a fiber shape with an am diameter of 0.4 to 2O0μ0, a maximum fiber length of 2Omm, and an aspect ratio of 50 to 5000, and has a chemical formula of Mho-nT io 2 (M is an alkali metal) of 11 Compounds in which is 6 and 8, M2Ti=01s, and compounds in which some of these titanium atoms are replaced with iron atoms are obtained.

In the case of alkali 6 titanate, the amount of iron added is Fe2O3/
The molar ratio of T i O2 is preferably 0.17 or less.

Firing can be carried out over a relatively wide temperature range, but
The temperature is preferably in the range of 00 to 1250°C, preferably around 1150″C.

8 In the case of alkali titanate, the general chemical formula MxTis-xFexo+s (0< x≦
The following two types of compounds represented by 4) are obtained. That is, when the amount of iron added is in the range of 0.17 to 0.4 in the molar ratio of Fezo 3/Tio 2, the firing temperature is 90
A compound with a layered crystal structure is obtained by firing at a temperature in the range of 0 to +2O0' (:, preferably 1150°C or lower. Then, the amount of iron added is Fe2Os/T
When the molar ratio is in the range of 0.05 to 0.17 in terms of +02, a compound having a tunnel structure can be obtained by processing at a firing temperature of 1150 to 1350°C, preferably 1220°C or higher. This is a compound known by its name as briplite. The relationship between the chemical composition of the product and the reaction temperature is schematically shown in Figure @1.

In order to obtain alkali metal titanate crystals in which WL fibers have grown sufficiently, it is preferable to slowly raise the temperature to a predetermined firing temperature. The temperature raising process does not necessarily have to be a constant rate and continuous operation, but is usually 6°C/min to IO°C.
It is desirable to do this within the range of /minute. Baking time is usually about 4
The predetermined reaction conditions can be satisfied if the reaction time is 5 minutes to 20 hours.

After the reaction has been carried out for a certain period of time, there is no particular need for slow cooling.

No significant difference was observed in the size of the fibrous crystals due to rapid cooling. Since the temperature increase rate has a large influence on the size of #1 & fibrous crystals, precise control is especially important at temperatures as high as 600°C.

The details of the reason for this are not clear, but for example, oxygen-containing alkali metal compounds undergo thermal decomposition during firing, and gases such as γ gas generated are easily fibrillated. & It is thought that it brings about the fiber shape. Furthermore, it is also believed that the oxygen-containing iron compound added in a small amount is involved in nucleation and promotes the growth of fiber-shaped crystals.

The crystalline fibrous alkali metal titanate salt produced by the above reaction consists of a nodule rich in w and m qualities, which grows in the form of needles from the surface of the nodule. Since this nodule contains a large amount of water-soluble alkali metal compounds, the defibration process can be carried out by pouring the produced mm material into cold water or hot water and using a disper stirring method or the like. in this case,
It is preferable to leave the nodules in cold or hot water for at least 1 hour so that they are fully absorbed in the water. Various known defibrators can be used. After thoroughly defibrating and separating the dispersion liquid, it is washed with water. The alkali titanate fibers obtained by drying do not lose their crystal shape through defibration treatment, and are long fibers with a high aspect ratio.

(Example) A detailed explanation will be given below using examples.

Example 1 Commercially available reagents titanium oxide (atetase type), potassium nitrate and V52 iron nitrate were each mixed in a molar ratio of TiO2/2O to 3
．． 9 and Fe2O*/T+02 molar ratio 0
．． 012, and mechanically pulverize and mix for sufficient time #j1. Next, this raw material powder was filled into an alumina crucible and placed in a heating furnace. Increase the heating rate to 10
°C/min and held at 1200°C for 10 hours. Thereafter, it was slowly cooled to about 900°C at a cooling rate of 10°C/min.
The heating power was turned off. Inside the crucible taken out of the furnace, pale yellow needle-shaped crystals resembling chestnut shells were growing. Most of these crystals have a diameter of 3 to 4 μm% and an R of 4 to Gtnm.
It has been found from observations using a stereoscopic microscope and a scanning electron microscope that it has a maximum aspect ratio of nearly 1000. Also,
Powder X-ray diffraction and chemical analysis revealed that the crystals were potassium hexatitanate containing trace amounts of iron. The results of differential thermal analysis suggested that this crystal had an exothermic peak at 1320°C and decomposed and melted in air.

Example 2 The starting material was prepared in the same manner as in Example 1, and about 0.5 g of distilled water was added thereto. Next, firing treatment was performed under the same conditions as in Example 1. The situation of the obtained product is as follows:
The results were roughly the same as in Example 1, but the length of the needle-like crystals that grew on the surface of the fibrous nodules was 5 to 7 inches, which means that they had grown longer than in Example 1. , the 7 spectral ratio of this potassium hexatitanate a-fiber is as shown in Example 1.
were in almost the same range.

Example 3 Titanium hydroxide, potassium nitrate and ferric oxide were each
The molar ratio of iO2/K2O is 3.6 and Fc2O-
/TiO2 molar ratio is 0.052,
Thorough mechanical mixing. As in Example 1, this was filled into an alumina crucible and placed in a heating furnace.

The temperature was raised at a rate of 5° C./min and held at 1200° C. for 12 hours. Thereafter, the heating power was immediately turned off and a rapid cooling operation was performed to complete the reaction. The crucible taken out from the furnace contains 5 to 81
Pale yellow needle-shaped crystals with a length of 6111 were growing on the surface of the fibrous nodule. After immersing the fibrous product in the nodules in water, it is defibrated using a disper stirrer, and then transported to different locations.
Obtained by washing with water and drying. It was observed that all of these crystals exhibited a spectral ratio of 700 to 1500.

From the results of X-ray diffraction and chemical analysis, these are 1.2n
It turned out to be potassium hexatitanate containing +o1% iron.

Example 4 Titanium oxide, cesium nitrate and ferric nitrate were each qT
The molar ratio of i Oz/CS2O is 2.75 and F (!
Weigh so that the molar ratio of 2O3/T i O2 is 0.231, and mix thoroughly using two hands. As in Example 1, this was filled into an alumina crucible and placed in a heating furnace. The heating rate was set to 10 for 7 minutes, and the temperature was maintained at 1050°C for 6 hours.

Thereafter, the heating power was immediately turned off and a cooling operation was performed to stop the reaction. When the crucible was taken out of the furnace, a-thin crystals were found stuck to the walls in clusters. The fibrous product in the nodule is coarsely crushed and soaked in water, and then placed in a heating bath for 2 hours.
It was then left to dry separately.

Next, this was defibrated using a jet pulverization method (PJM-100 model, manufactured by Nippon Pneumatic Industries Co., Ltd.) to obtain fibrous crystals. All of these crystals have a length of 1.5 to 2
It was cesium octatitanate with a τ of 0 and a 7subvecto ratio of 500 to 1250.

Example 5 Titanium hydroxide slurry (chemical analysis value Ti○229, 9%
, H2SO, 4,17%) contained in the titanium hydroxide slurry in a container equipped with a high-speed stirrer.
After adding 7 um of hydroxide for neutralization, add sodium nitrate to a solution with a molar ratio of TiO2/Na70 of 2.0.
So that ′:f! 4 to thoroughly mix and dissolve. Next, the slurry was dried using a spray dryer (Okawara Kakoiso Co., Ltd., model QC-16) to obtain a dry raw material in the form of granules with good fluidity. This raw material was placed in an alumina crucible and fired under the same conditions as in Example 3. After completion of the reaction, the obtained product is sodium octitanate,
Average fiber diameter 2O0~G00μIII, average fiber length 4~f
It was a needle-like crystal of 3m+n.

Example 6 Titanium oxide (anatase type), potassium nitrate, and ferric nitrate were prepared at a molar ratio of Tio 2/Kzo of 3.2 and 1/2, respectively.
F e 2O. /TiO2 molar ratio of 0.125, and mechanically pulverized and mixed for a sufficient period of time. Next, this raw material powder was filled into an alumina crucible and placed in a heating furnace. The heating rate was 7°C/min, 127
It was held at 0°C for 15 hours. Thereafter, the temperature was gradually cooled down to 1000°C at a rate of 20°C/min, and the heating power was turned off. In the crucible taken out from the furnace, the average fiber diameter was 40-12O.
μm, average fiber, 11i, 6-15m button, maximum 30
Brown crystals with an aspect ratio close to 0 were observed.

As a result of powder X-ray diffraction and chemical analysis, this crystal was clearly found to be potassium octitanate containing 1% iron in 2O+oo with a bripyrite structure.

(Effects of the Invention) According to the method of the present invention, the fibers produced have advantages such as having a better length than known fiber lengths, having a large aspect ratio and high strength, and being easy to separate from fibrous nodules. You can get the same effect.

[Brief explanation of drawings]

1st UXJ Ha departure FX n l: B it”, T
A product obtained under conditions where the molar ratio of iO2/M2O (M is potassium, an alkali metal) is fixed at 4;
Reaction temperature and starting materials Fe2O )/T i O
The relationship between the molar ratio of
Figure 0.10.2O. 3040.5 F e 2O3 / T + 02 (molar ratio) A 6
Titanate B 6 titanate + 8 titanate C 8 titanate D KFeO, +8 titanate E Bryprite

Claims (4)

[Claims] (1) A mixture of a titanium source compound, an oxygen-containing alkali metal compound, and a small amount of an oxygen-containing iron compound at a concentration of about 900 to 1,350
1. A method for producing a long fibrous alkali metal titanate salt, which is characterized by firing at a temperature range of °C. (2) The mixing ratio of the titanium source compound and the oxygen-containing alkali metal compound is in the molar ratio of TiO_2/M_2O (M represents an alkali metal) from 4.0 to 2.2, and the addition ratio of the oxygen-containing iron compound is Fe_2O_3 /TiO_2 molar ratio 0.4
The manufacturing method according to claim 1, which does not exceed. (3) The production method according to claim 1, wherein the oxygen-containing alkali metal compound is an alkali metal nitrate. (4) The oxygen-containing iron compound is iron nitrate, sulfate, chloride,
The manufacturing method according to claim 1, which is an oxide or a hydroxide.