KR101150075B1 - Manufacturing Method of Nano and Micro Size Potassium Titanate Whisker Using Dry Diffusion Breaking and Continual Growth Crystallization Method - Google Patents

Abstract

The present invention relates to a method for producing nano and micro size of industrial potassium titanate whisker, the method of producing potassium titanate whiskers or potassium titanate granules using the disintegration effect, the disintegration effect, crystal continuous growth effect, or combination of both to grow potassium titanate whisker It is characterized by.

According to the present invention as described above, the economical benefits, such as can significantly reduce the production cost of K ₂ Ti ₆ O ₁₃ whiskers is very high.

Whisker, potassium titanate, diffusion decay method, continuous crystal growth method

Description

Manufacturing Method of Nano and Micro Size Potassium Titanate Whisker Using Dry Diffusion Breaking and Continual Growth Crystallization Method}

The present invention relates to a method for producing nano and micro size of industrial potassium hexatitanate whisker, and in particular, to deal with the preparation method for preparing potassium titanate whisker or potassium titanate granules using the diffusion collapse effect by the dry method, as well as dry series-parallel continuous crystal It relates to a method for producing a micro K ₂ Ti ₆ O ₁₃ whisker by the growth method.

K ₂ Ti ₆ O ₁₃ whiskers not only have excellent mechanical performance, but also have very unique physicochemical properties due to their tunnel structure. Examples include high infrared reflectance, low thermal conductivity, high heat resistance, high wear resistance, high dielectric insulation and low dielectric constant, and chemical stability. K ₂ Ti ₆ O ₁₃ whiskers have excellent performance and are much lower in cost than other whiskers, so they are widely applied and have good prospects. Especially, K ₂ Ti ₆ O ₁₃ whiskers are made of K ₂ Ti ₆ O ₁₃ whiskers. Friction materials are used as brake blocks in luxury cars and small cars. In addition, as it is applied to thermal insulation materials, heat-resistant insulation materials and building materials, the demand is expected to exceed thousands of tons. Whisker-reinforced thermoplastic, thermosetting plastic composites are used as an ideal important material for automobiles and other precision equipment, equipment. In addition, various functional characteristics of K ₂ Ti ₆ O ₁₃ whiskers have been developed and applied to paint, military, chemical, paper, and the like. However, the high cost of production is still the major obstacle to expanding the application of K ₂ Ti ₆ O ₁₃ whiskers. The main production methods of K ₂ Ti ₆ O ₁₃ whiskers include sintering method, improved sintering method (including KDC method, rapid cooling sintering method, general cooling sintering method), hydrothermal method, melting method, solvent method, and crushing method. Among them, the sintering method and the improved sintering method are simple in process and have advantages in continuous scale production. Therefore, the sintering method and the improved sintering method are mainly applied to the commercial production of K ₂ Ti ₆ O ₁₃ whiskers, and more than half of K ₂ Ti ₆ O ₁₃ whiskers are It is produced in several ways. The K ₂ Ti ₆ O ₁₃ whisker is one of the few whiskers with some success in commercial applications, but it is still far from mass production. In particular, expensive production costs have become a major cause of restricting the scope of application. Therefore, in order to apply them as a universal whisker, it is necessary to reduce production costs.

The commonly used K ₂ Ti ₆ O ₁₃ whisker sintering method generally mixes potassium and titanium dioxide compounds at a certain mole ratio, but most of them are made of TiO ₂ and K ₂ CO ₃ as raw materials. It is manufactured by a process, and is manufactured by adding an appropriate amount of auxiliary material. Depending on the manufacturing method, there are many differences in the heating synthesis time, which may reach up to 100 hours. High temperature conditions, long heating requirements and complicated processes are the main causes of cost increases. In general, K ₂ Ti ₆ O ₁₃ whisker is heated at a high temperature of about 1100 ℃, this high temperature consumes a lot of energy, high potassium consumption, and due to alkaline synthetic conditions severe damage to equipment corrosion. Therefore, lowering the heating temperature is the most effective way of reducing the production cost, a solution for this is required. However, when the firing temperature is lowered for cost reduction, when the temperature is 1000 ° C. or less, the whisker is not made only in a granular form.

_What is TiO ₂ amorphous _? If nH ₂ O is used as a raw material, it can be synthesized with K ₂ Ti ₆ O ₁₃ whisker in the temperature range of 1080 ~ 1123 ℃, and the synthesis temperature can be lowered by 50 ~ 100 ℃ than crystalline rutile or anatase TiO ₂ . It started in that it is possible.

In addition, as a technical problem for cost reduction, the synthesis of whiskers is made of titanium dioxide and potassium compounds, which are commonly available, as raw materials, and nano or micro grade K ₂ Ti ₆ O through the decay process by high temperature heating in a furnace. ₁₃ You need an economical recipe to make whiskers.

The present invention overcomes these shortcomings, and deals with the production method of potassium titanate whiskers and potassium titanate granules using the decay effect, and particularly relates to a method for producing micro K ₂ Ti ₆ O ₁₃ whiskers by a series-parallel continuous crystal growth method. . That is, the present invention synthesizes potassium titanate whiskers using a dry collapse effect and a series-parallel continuous crystal growth effect. Synthesis of whiskers is based on general titanium dioxide and potassium compounds.

In the method of the present invention, whiskers are synthesized by diffusion disintegration again during the heating process, or serially and serially grown in a nanoscale to synthesize micro-class K ₂ Ti ₆ O ₁₃ whiskers. Through the examples below, the present invention can be described again. The C _d value and the particle size range of titanium dioxide related thereto are not fixed values depending on the raw material conditions and process conditions. In fact, the C _d value is influenced by the following factors in the synthesis of potassium titanate whiskers. Crystals of titanium dioxide, particle size distribution of titanium dioxide raw material, purity of titanium dioxide and type and content of metal elements contained, mixing ratio of potassium and titanium dioxide in raw materials, content of other auxiliary raw materials in raw materials, heating process and gaseous environment, It is affected by the heating environment. The main synthesis procedure proposed in the present invention is as follows.

1) Mix the titanium dioxide and potassium compound in a mole ratio of 1: 1 to 8: 1.

2) Heat the mixed powder at 800 ~ 1300 ℃ for 0.2 ~ 6 hours.

3) Wash with water and dry.

As a main element of the manufacturing technology of the potassium hexatitanate whisker of the present invention, the final product by controlling the size of the raw material can be adjusted. Here, the particle size of titanium dioxide is a decisive factor of the growth method of potassium titanate whisker, and the particle size is based on the critical particle size C _d . If the particle size of titanium dioxide is larger than C _d , the titanium dioxide grows to potassium titanate whisker by the decay method. If the raw material particle size of titanium dioxide is smaller than C _d , the titanium dioxide is grown as potassium titanate whisker in a series-parallel connection method. Here, C _d may be defined as between 60 and 300 nm.

The particle size of titanium dioxide is either (1) disintegrating directly with nano potassium titanate whiskers or serially parallel synthesis with micro potassium titanate whiskers again on this basis, the particle size is between C _d ~ 500 nm, (2) direct micro potassium titanate whisker The particle size should be smaller than C _{d in the} case of decomposing and synthesizing with (S) a series-parallel continuous crystal growth synthesis from the nano Potassium titanate whisker (diameter of 100 nm or less).

When decay synthesis directly with nano potassium titanate whiskers and then in series-parallel synthesis with micro potassium potassium titanate on this basis, the following two processes can be chosen.

(1) The temperature is adjusted to two stages of heating. In other words, first heating at 900 ~ 1050 ℃ for 0.2 ~ 6 hours, disintegrate with nano potassium titanate whisker, and then again to increase the temperature to 1050 ~ 1300 ℃ and heated for 0.2 ~ 6 hours to continuously grow crystals with micro potassium titanate whisker Synthesize

(2) In the primary heating process, the mixture is heated directly at 900 ~ 1300 ℃ for 0.2 ~ 6 hours and synthesized directly into micro potassium potassium titanate whisker or granule.

Titanium dioxide refers to rutile type, anatase type, or the like, or a mixture of one or more thereof.

Potassium compounds refer to industrial potassium carbonate. The furnace gaseous environment is heated either directly in air or under vacuum conditions, or under potassium compound conditions, or a combination of any two gases.

The present invention is a novel manufacturing method for controlling the growth of potassium titanate whiskers using the dry method collapse effect and the series-parallel continuous crystal growth effect, and can be called a completely new method of synthesis of potassium titanate whiskers. This method significantly lowers the production cost of K ₂ Ti ₆ O ₁₃ whiskers, has better market prospects than existing sintering methods and similar products, and has very high economic benefits. The advantages are as follows.

(1) The raw materials used in the method proposed in the present invention are all commercially available raw materials currently available, and the furnace (microwave) price is also low, and is suitable for large-scale continuous industrial production.

(2) The heating synthesis temperature was significantly lowered by about 100 ~ 200 ℃ (compared to the reference temperature of 1100 ℃), and the heating synthesis time was also significantly shortened.

(3) The process is simple and the K ₂ Ti ₆ O ₁₃ whisker can be synthesized at once by using the decay effect, which is suitable for large scale industrial production.

(4) Material consumption, equipment damage and energy consumption can be greatly reduced.

(5) Scale production of nano and micro grade K ₂ Ti ₆ O ₁₃ whiskers can be carried out at the same time, and the cost of nano K ₂ Ti ₆ O ₁₃ whiskers is rather cheaper than micro K ₂ Ti ₆ O ₁₃ whiskers. have.

That is, the decay effect and the continuous crystal growth effect can be applied to the heat synthesis of potassium tetracarbonate and potassium 8 titanate whiskers or granules. The present invention can be produced by a heating production equipment (microwave), and thus the manufacturing cost is low, and the process is Simple, easy to control, low heating temperature, short production cycle, mass production. In addition, the cost of the produced potassium titanate whisker is low, the quality is excellent, and it is possible to complete the synthesis of micro, nano K ₂ Ti ₆ O ₁₃ whisker by general equipment or general raw materials, and unlike the general understanding, nano K ₂ Ti ₆ The production cost of O ₁₃ whiskers is rather cheaper than micro K ₂ Ti ₆ O ₁₃ whiskers.

Photo 1. Potassium titanate whisker (K ₂ Ti ₆ O ₁₃ A) crystal structure and TEM photo

The present invention belongs to the nano, micro-whisker manufacturing technology domain and proposes a method for producing potassium titanate whisker or potassium titanate granules by using the dry diffusion decay effect, and in particular in the micro-size at nano size by using the serial parallel crystal growth effect It is characterized by the manufacturing method of K ₂ Ti ₆ O ₁₃ whisker. This method synthesizes potassium titanate whiskers using the decay effect and the parallel-series crystal growth effect. The raw materials required for the synthesis of whiskers are commonly available titanium dioxide and potassium compounds, which are directly decomposed and synthesized by heating at a high temperature in a furnace, or are simultaneously formed by diffusion decay and crystalline continuous growth synthesis, or nano or micro K ₂ Ti ₆ O ₁₃ whiskers. Characterized in that can be synthesized.

The method for preparing potassium titanate whiskers or potassium titanate granules using the nano- and micro-manufacturing technology areas to be presented in the present invention and using the dry disintegration and continuous crystal growth effects may be prepared in the following examples.

Example 1 It can be directly decomposed into nano K ₂ Ti ₆ O ₁₃ whiskers.

(1) Compress and mold after mixing TiO ₂ (particle diameter 100 ~ 300nm, average 200nm) and industrial potassium carbonate in mole ratio 3: 1.

(2) The mixed powder is heated at 950 ° C. for 1 hour under rapid collapse heating.

(3) It can be washed and dried to obtain nano K ₂ Ti ₆ O ₁₃ whiskers (diameter of 100 nm or less).

Example 2 Micro K ₂ Ti ₆ O ₁₃ whiskers may be synthesized by indirect collapse and serially parallel crystal growth effects.

(1) Dry mix TiO ₂ (particle diameter 100-300 nm, average 200 nm) and industrial potassium carbonate in a mole ratio of 4: 1.

(2) 0.5 hours under mixed powder rapid disintegration heating at 950 ° C.

(3) Then, it heats at 1050 degreeC conditions for 1 hour.

(4) Wash and dry to obtain a micro K ₂ Ti ₆ O ₁₃ whisker (diameter 100 nm or more).

Example 3 Micro K ₂ Ti ₆ O ₁₃ whiskers may be synthesized by indirect collapse and serially parallel crystal growth effects.

(1) Dry mix TiO ₂ (particle diameter 100-300 nm, average 200 nm) and industrial potassium carbonate in a mole ratio of 5: 1.

(2) The mixed powder is heated at 1000 ° C. for 2 hours under rapid collapse heating.

(3) Wash and dry to obtain a microK ₂ Ti ₆ O ₁₃ whisker (diameter 100 nm or more).

Example 4 Micro K ₂ Ti ₆ O ₁₃ whiskers can be synthesized by direct diffusion collapse.

(1) Dry mix titanium dioxide (particle average diameter: 5 nm) and potassium dioxide with a mole ratio of 3: 1.

(2) The mixed powder is heated at 1100 ° C. for 1 hour in rapid decay heating.

(3) It can be washed and dried to obtain micro K ₂ Ti ₆ O ₁₃ whiskers (diameter of 100 nm or more).

Example 5 Micro K ₂ Ti ₆ O ₁₃ whiskers may be synthesized by indirect collapse and serially parallel crystal growth effects.

(1) Yellow TiO ₂ (average particle diameter 400 nm) and saturated industrial potassium carbonate solution are mixed at a mole ratio of yellow TiO ₂ and potassium carbonate 3: 1, mixed, put into a heating furnace and dried for 3 hours at 300 ° C., followed by pulverization. .

(2) After grinding, the mixed powder is heated for 0.5 hour at 1050 ℃ under rapid collapse heating.

(3) Wash and dry to obtain a micro K ₂ Ti ₆ O ₁₃ whisker (100 nm or more in diameter).

Example 6 A nano K ₂ Ti ₆ O ₁₃ whisker can be synthesized directly using nano TiO ₂ as a raw material.

(1) Dryly mix nano TiO ₂ (15 nm in average particle diameter) with potassium dioxide at a mole ratio of 3: 1.

(2) The mixed powder is heated at 850 ° C. for 2 hours in rapid decay heating.

(3) Wash and dry to obtain nano K ₂ Ti ₆ O ₁₃ whiskers (diameter of 100 nm or less).

Description of the growth structure of the potassium titanate whisker covered in the above embodiment is as follows. First, a structure in which titanium dioxide granules are diffused and collapsed to grow into potassium titanate whisker is technically completed by the following mechanism.

(1) In view of the principle of the synthesis of the micro potassium phosphate whisker by the decay effect, first, the synthesis of the potassium titanate whisker consists of the collapse of the TiO ₂ granules. A micro grade K ₂ Ti ₆ O ₁₃ whisker was synthesized by heating and decomposing a rod type micro grade TiO ₂ (average size 1500 × 5000nm). However, after 3 hours of heating at 1000 ℃, the decomposed synthetic state of K ₂ Ti ₆ O ₁₃ whiskers is not completely achieved, and after further heating at 1100 ℃ for 20 minutes, it is completely decomposed and synthesized into K ₂ Ti ₆ O ₁₃ whisker. do.

(2) Synthesis principle of decay synthesis of nanoscale potassium titanate whisker The decay growth of potassium titanate whisker is mainly achieved through rapid diffusion of K, O and Ti atoms. Therefore, when small TiO ₂ is used as a raw material, the atomic diffusion path of whisker decay synthesis is shortened, and thus the heating temperature and time required are greatly reduced, and the size of potassium titanate whisker after decay is also reduced. In other words, when TiO ₂ of a small size is used as a raw material, the nano decay of the K ₂ Ti ₆ O ₁₃ whisker is achieved, and the heating temperature and time can be shortened. When TiO ₂ granules having a particle diameter of 100 to 300 nm (200 nm on average) are used as a raw material to disintegrate K ₂ Ti ₆ O ₁₃ whiskers, the TiO ₂ disintegration has the effect of nano disintegration and thus nano-grade K ₂ Ti ₆ O ₁₃ Whiskers (average diameter 60 nm) can be obtained. In addition, heating at 900 ° C. for 0.5 hour causes a complete decay into nano grade K ₂ Ti ₆ O ₁₃ whiskers. Compared with the traditional process, the heating temperature is significantly lowered by about 100 ~ 200 ℃, accordingly, the heat production cycle is also significantly shortened, it is only necessary to work 0.5 to 1 hours at 900 ℃ conditions.

Secondly, the principle of the crystal continuous growth effect of potassium titanate whisker shows that the existing potassium titanate (including potassium titanate whisker collapsed by the whisker collapse effect) is parallel to each other to form a larger whisker in a parallel and parallel manner. In addition, the diameter of the whiskers is increased in a merged manner. Collapsed on the nano ₂ Ti ₆ O ₁₃ whiskers is K may be synthesized by the micro-level K ₂ Ti ₆ O ₁₃ larger and more thick again as the serial-to-parallel connection mode whiskers.

And, it is when the growing whisker of potassium titanium as titanium dioxide granules or series-parallel connection of the granular potassium titanate is the particle size of the TiO ₂ material is small enough, the collapse phenomenon of the TiO ₂ more in the calcining process weak. In this case, it is mainly expressed as continuous crystal growth, and all four types are characterized.

(1) Tiny TiO ₂ granules are directly serially paralleled by atomic diffusion of K, O and Ti to form potassium titanate whiskers.

(2) Tiny TiO ₂ granules first form potassium titanate granules or intermediates and dosing products due to atomic diffusion of K, O and Ti, and then form potassium titanate whiskers in series-parallel connection.

(3) The two forms coexist.

(4) Potassium titanate whiskers already formed are lengthened through parallelism or thickened by merging.

However, the crystal continuous growth and the parallel-parallel growth itself suggest that small TiO ₂ granules or potassium titanate granules with different crystals are constantly being adjusted. Therefore, there must be a large amount of continuous atomic diffusion, which is affected by heating temperature and time.

(1) When TiO ₂ having a particle diameter of 60 to 150 nm (average particle diameter of 100 nm) is used as a raw material, the heat synthesis of the K ₂ Ti ₆ O ₁₃ whisker mainly grows due to the crystal continuous growth effect. The heating composition of K ₂ Ti ₆ O ₁₃ whisker is not completely completed even when heated for 3 hours at 1000 ℃. Therefore, it is impossible to synthesize potassium titanate whiskers using TiO ₂ having a small particle size within this particle size range.

(2) When TiO ₂ having an average particle diameter of 10 to 20 nm is used as a raw material, the heat synthesis of K ₂ Ti ₆ O ₁₃ whisker can be mainly synthesized by the crystal continuous growth effect, wherein the surface energy of the nano TiO ₂ raw material is Very large and extremely small diffusion distance, nano grade K ₂ Ti ₆ O ₁₃ whisker with only 2 hours heating at 800 ℃ It is possible to synthesize.

In addition, the heat growth of K ₂ Ti ₆ O ₁₃ whisker synthesized for diffusion collapse and crystal continuous growth synthesis of potassium titanate whisker has two completely different growth structures. In other words, when the nano-TiO ₂ granules are very small in size, the growth of K ₂ Ti ₆ O ₁₃ whisker is mainly based on the serial and parallel connection, when the TiO ₂ of large quasi-micro, micro or larger size is used as the raw material, The growth of the K ₂ Ti ₆ O ₁₃ whiskers first appeared as a structure of diffusion decay growth, and then gradually increased and thickened by a series-parallel connection. Therefore, as the size of the small TiO ₂ granules grows larger and the size of the larger TiO ₂ granules decreases, there is necessarily one adjacent size C _{d. If} the size of the TiO ₂ granules is smaller than C _d , K ₂ Ti ₆ O ₁₃ whiskers The growth of is mainly due to the serial-to-parallel connection, and when the TiO ₂ granule size is larger than C _d , the growth of the K ₂ Ti ₆ O ₁₃ whisker may be grown primarily by diffusion collapse.

The size of the TiO ₂ granules is a key factor in determining the growth structure of K ₂ Ti ₆ O ₁₃ whisker, and the present invention primarily determines the critical size C _d of TiO ₂ between 60 and 300 nm. In practice, however C _d values in the potassium titanate whisker synthesis process because the C _d is a value, as the descriptive fixed according to the material condition and the process condition is influenced by the following factors. Crystal shape of titanium dioxide, particle size distribution of titanium dioxide, purity of titanium dioxide and type and content of metal elements contained, mixing ratio of potassium and titanium dioxide in raw materials, other auxiliary components and contents of raw materials, heating process and environment, gaseous environment Is affected.

TiO ₂ raw material size is K ₂ Ti ₆ O ₁₃ when the ball and the points on a distinct influence on the heating temperature and time required for heating the synthesis of whiskers also given the TiO ₂ raw material cost problem, a large TiO ₂ raw material or the smaller TiO ₂ raw material size Not all of them are optimal. The present invention K ₂ Ti ₆ O ₁₃ on the basis of the spreading depletion and series-parallel connection growth conditions and the structure of the whiskers, no new K ₂ Ti ₆ O ₁₃ there proposes a whisker synthesis method, the main principle as the adjacent size Size C _d It is characterized by using slightly larger titanium dioxide as a raw material and decomposing and synthesizing nano K ₂ Ti ₆ O ₁₃ whiskers by using the nano decay effect first appeared in the heating process. The next step is to synthesize micro-class K ₂ Ti ₆ O ₁₃ whiskers using a series-parallel continuous crystal growth structure (which can increase the heating temperature or extend the time). Then, due to the collapsed nano-effects, the heating temperature can be drastically lowered, and the heating time can be greatly shortened. The result is a characteristic that can be applied to other titanium dioxide.

Photo 2. Synthesized K ₂ Ti ₆ O ₁₃ Whiskers Photo Photo 3. Synthesized K ₂ Ti ₆ O ₁₃ Whiskers Photo

Claims (10)

Potassium titanate whisker manufacturing method, the method (1) mixing the titanium dioxide and the potassium compound in a molar ratio of 1: 1 to 8: 1 to prepare a mixed powder; (2) preparing a potassium titanate whisker by heating the mixed powder at 800 to 1300 ° C. for 0.2 to 6 hours; And (3) washing the potassium titanate whisker with water, wherein the potassium titanate whisker size and synthesis method are determined according to the critical size (C _d ) of the titanium dioxide particle size, and the titanium dioxide particle size is the critical When the size (C _d ) or more and 500 nm or less, micro potassium titanate whiskers having a diameter of 100 nm or more are serially connected and synthesized, and when the titanium dioxide particle size is equal to or less than the critical size (C _d ), the nanoparticle having a diameter of 100 nm or less that is serially and serially crystallized Potassium titanate whisker is synthesized, wherein the critical size (C _d ) is a method of producing potassium titanate whisker, characterized in that 60 to 300nm. The method of claim 1, When the micro potassium potassium titanate whisker is synthesized in series-parallel, the heating of step (2) (4) first heating the mixed powder at a temperature of 900 ° C. to 1050 ° C. to synthesize nano potassium titanate whisker; And (5) a method of producing potassium titanate whisker, comprising the step of second heating the synthesized nano potassium titanate whisker to a temperature of 1050 ° C to 1300 ° C. The method of claim 1, When directly synthesizing micro potassium titanate whiskers having a diameter of 100 nm or more from the mixed powder of step (1), the particle size of the titanium dioxide is characterized in that 500 nm or more whisker production method. 3. The method of claim 2, The first heating is performed for 0.2 to 6 hours, the second heating method for producing potassium titanate whisker, characterized in that for 0.2 to 6 hours. The method of claim 1, The titanium dioxide is a potassium titanate whisker manufacturing method characterized in that the material of at least one of rutile type, anatase type or yellow titanium dioxide. delete The method of claim 1, Potassium titanate whisker production method characterized in that the potassium compound is industrial potassium carbonate or potassium dioxide. The method of claim 1, The method of claim 2, wherein the heating of the step (2) is carried out in a gaseous environment containing air, vacuum, or a potassium compound. The method of claim 1, The heating of step (2) is a method for producing potassium titanate whisker, characterized in that using a microwave equipment. delete