CN1176161C - Preparation of dispersed slurry of nano rutile titanium dioxide - Google Patents

Abstract

The invention provides a method for preparing a rutile phase nano-titanium dioxide dispersion slurry, which comprises the following steps: (1) adding titanium tetrachloride under stirring in water at 0°C; (2) hydrolyzing with electromagnetic stirring at room temperature to obtain a hydrolyzed slurry (3) convert the hydrolyzed slurry into a rutile phase structure by crystallization; (4) pour the supernatant liquid after the hydrolyzed slurry transformed into a rutile phase structure is allowed to stand, and wash the lower layer slurry with water until the pH value is 1～ 4; (5) adding water to the slurry in the lower layer, electromagnetically stirring and dispersing, and then ultrasonically dispersing to obtain the rutile phase nano-titanium dioxide dispersion slurry. This method does not undergo high-temperature heat treatment, and can prepare rutile phase nano-titanium dioxide dispersion slurry in one step of low-temperature hydrolysis in the liquid phase. The prepared slurry has good stability, high solid content, and is relatively simple and convenient to use; this method is comparable to the prior art. The invention has the advantages of simple preparation process, convenient industrial production and low production cost, and has obvious economic benefits.

Description

Preparation method of rutile phase nano titanium dioxide dispersion slurry

Technical field

The invention relates to a preparation method of rutile phase nano-titanium dioxide dispersion slurry, which belongs to the field of fine chemical industry.

Background technique

Nanometer titanium dioxide (TiO ₂ ) came out in the late 1980s and is an important inorganic material. Due to its many unique physical and chemical properties, such as large specific surface area, high surface activity, good thermal conductivity, good light absorption performance, Good dispersibility, etc., so it is widely used in coatings, paper making, plastics, printing, chemical fiber, rubber, cosmetics, catalysts, antibacterial agents, sewage treatment and other industries. Titanium dioxide exists in three crystalline forms in nature: rutile, anatase and brookite. Generally, the anatase phase is formed at low temperature, and the rutile phase is formed at high temperature, so it is difficult to produce small-scale nano-rutile phase. Due to its high refractive index, good stability and superior performance, rutile TiO ₂ has been widely used in coatings and other aspects. It has more uses than anatase. How to control nano-rutile TiO ₂ has become a problem that researchers attach great importance to. .

In the application of nano-powder materials, the current dispersion technology is the key to the performance of nano-materials. The dispersion of nano-TiO ₂ in aqueous solution directly affects its practical application in nano-electroplating, photocatalytic coatings and other industries. In the aqueous suspension of nano- _TiO2 particles, due to the activity of the particle surface, they are easily agglomerated together to form larger aggregates with several connecting surfaces, which reduces the utilization rate and greatly reduces the nano-performance. To disperse nanoparticles uniformly and stably in the liquid medium, the following three stabilization mechanisms are usually used: 1) electrostatic stabilization mechanism; 2) steric stabilization mechanism; 3) electrical steric stabilization mechanism. The study found that the rutile TiO ₂ powder prepared by high temperature treatment is difficult to prepare a highly dispersed and stable nano slurry due to the large size of the nanoparticles and the hard agglomeration of the powder itself.

TiO ₂ nanoscale materials have been one of the most popular research fields at home and abroad recently. Most of the research is focused on exploring various new techniques to prepare nanoscale TiO ₂ . Research has shown that TiO ₂ can be prepared by liquid-phase methods such as sol-gel method, peptization method, oxidation method, and gas-phase methods such as inert gas in-situ pressurization method, gas-phase hydrolysis method, and thermal cracking CVD method. Among the disclosed known technologies, Chinese patent CN1217297 discloses a "method for preparing nano-scale rutile titanium dioxide". Roasting at 500-650°C, then dissolving, and finally crystal transformation at 800-900°C; this method is complex and requires high-temperature calcination to obtain rutile phase titanium dioxide, and the obtained titanium dioxide has low purity. Chinese patent CN1343745 discloses "a method for preparing rutile-type titanium dioxide". This method uses tetravalent titanium liquid as the main raw material, and prepares rutile-type nano-titanium dioxide through hydrolysis, sorting, washing, dispersion and roasting; this method It also needs to go through the operation steps of roasting heat treatment, and the process is also more complicated; a kind of "method for synthesizing nano-rutile titanium dioxide with large specific surface area by hydrolysis of titanium tetrachloride at room temperature" is disclosed in Chinese patent CN1289724. This method uses _TiCl4 as raw material The precursor is obtained by hydrolysis, and the nano-rutile TiO ₂ with large specific surface area is directly prepared in the next step at room temperature with β-cyclodextrin, SiO ₂ , Al ₂ O ₃ or TiO ₂ of different crystal forms. Although this method does not require a high-temperature roasting process, it needs to add a β-cyclodextrin cross-linking agent, which is costly and introduces organic impurities to be adsorbed in the particles. If it is not roasted at a high temperature, it is impossible to obtain pure rutile-type TiO ₂ , the introduction of "seeds" such as SiO ₂ , Al ₂ O ₃ or TiO ₂ of different crystal forms will make the prepared rutile TiO ₂ mixed with mixed crystals, which is not suitable for applications that require high-purity rutile TiO ₂ . The methods disclosed in the above-mentioned technologies are only for the preparation of rutile titanium dioxide powder, and rutile titanium dioxide dispersion slurry is often used in practical applications. Dispersion technology is the key to the performance of nanomaterials. Due to the activity of the particle surface, the nanoparticles are easily agglomerated together to form larger aggregates with several connecting surfaces, which reduces the utilization rate and greatly reduces the nano-performance; the nanoparticles are uniformly and stably dispersed in the liquid medium, often It needs to be realized through complex processes such as surface modification, selection of dispersant, and ultrasonic dispersion, but the current results are not ideal. On the one hand, it is difficult to disperse due to the severe agglomeration of the nanoparticles themselves after high temperature treatment; Organic dispersants, surfactants, etc. are not suitable for special applications.

Contents of the invention

The purpose of the present invention is to overcome the shortcoming of prior art, avoid preparing rutile phase TiO by anatase TiO ₂ high-temperature treatment solid phase reaction process, and solve the _problem that is difficult to prepare highly dispersed slurry due to the agglomeration of nanopowder, Research and invention of a preparation method for preparing highly dispersed and highly stable rutile phase nano-titanium dioxide dispersion slurry directly by hydrolyzing titanium tetrachloride in the next step at low temperature.

The technical purpose of the present invention is realized by following technical scheme: in the distilled water (ice-water mixing) of 0 ℃, slowly add titanium tetrachloride under vigorous stirring, the weight ratio 10 of water and titanium tetrachloride: (0.1～3 ), electromagnetic stirring at room temperature (20-30°C) for 2-5 hours to obtain a milky white slurry; this slurry can be transformed into a rutile phase structure after crystallization at 25-80°C for 2-3 days. The concentration of chloride ions in the material is high, the acidity is strong, and the slurry has the characteristics of obvious stratification. After standing still, pour the supernatant liquid, and the lower layer slurry is washed with distilled water for many times until the pH value is 1 to 4, and then transferred to a beaker and added with distilled water. Electromagnetic stirring Disperse for 0.5 to 2 hours, and ultrasonically disperse for 1 to 2 hours to obtain a rutile phase nano-titanium dioxide dispersion slurry. By controlling the final addition of distilled water and the weight ratio of water to titanium tetrachloride (1.0-8): 1, nano-titanium dioxide dispersion slurry with a solid content of 5-30% can be prepared.

The structure of the nano-titanium dioxide dispersion slurry obtained above after low-temperature drying was measured by a Japanese Rigaku D/max-IIIA X-ray diffractometer as a pure rutile phase (as shown in Figure 1). The rutile phase nano-titanium dioxide dispersion slurry prepared by the present invention has good stability and can be placed for more than 2 to 4 months; observed by a Japanese JEOL JEM-100CXII transmission electron microscope, the titanium dioxide particles in the slurry have good dispersion and less agglomeration. The particle size is between 10 and 100 nanometers (as shown in Figure 2); this slurry does not contain any organic surfactant and polymer dispersant, and can be directly used in nano-coating, nano-plating and other practical applications.

Compared with the prior art, the present invention has the following advantages and effects:

(1) Without high-temperature heat treatment, rutile phase nano-titanium dioxide particles can be prepared by one-step low-temperature hydrolysis in the liquid phase.

(2) Directly use the hydrolyzate to control the pH value to prepare a certain concentration of nano-titanium dioxide high-dispersion slurry in situ. The slurry has good stability and the solid content can be as high as 30%.

(3) The prepared nano-titanium dioxide dispersion slurry can be widely used directly in any solution with a pH value less than 6, and the titanium dioxide can be nano-dispersed in the whole solution only by ordinary mixing.

(4) The present invention is different from the metal ion surface modification commonly used at present or adopts the method for preparing nano-dispersion slurry by organic surfactant and dispersant treatment, and this nano-slurry does not contain the metal ion of other surface modification, does not contain any organic Surfactants and polymer dispersants are more advantageous for applications with special requirements, such as nano-plating.

(5) The present invention does not prepare titanium dioxide through high-temperature treatment, and does not use nano-powder to prepare the complicated method of dispersion slurry. The nano-titanium dioxide dispersion slurry with rutile phase structure is prepared from titanium tetrachloride in one step at low temperature, and the preparation process is simple and convenient for industrialization. Generation, can reduce production costs, and has obvious economic benefits.

Description of drawings

Fig. 1 is the X-diffraction (XRD) spectrum of the nano titanium dioxide dispersion slurry that the present invention makes.

Fig. 2 is a transmission electron microscope (TEM) photo of the nano-titanium dioxide dispersion slurry prepared in the present invention.

Detailed ways

The implementation of the present invention is relatively simple and easy, as long as the preparation method described in the above description is operated and implemented, the present invention can be well implemented. The inventor has obtained many successful examples through long-term research, and only enumerates a few embodiments below.

Example 1

Add 500ml of distilled water at 0°C to a 1000ml flask, slowly add 50g of TiCl ₄ (analytical pure) under vigorous stirring, the weight ratio of water to titanium tetrachloride is 10:1, and electromagnetically stir at room temperature (20-30°C) 3h; continue to stir the obtained milky white slurry at 25°C for 3 days, and then pour the supernatant after it is still; the lower slurry is suction filtered and washed with distilled water for several times until the pH value is 2; the filter cake is transferred to a beaker and 190ml of distilled water is added , that is, the weight ratio of added water to titanium tetrachloride is 3.8:1, electromagnetic stirring is dispersed for 1h, and finally ultrasonic dispersion is 1.5h to obtain the rutile phase nano-titanium dioxide dispersion slurry, the content of titanium dioxide in the slurry is 10%, stable Sex over 3 months.

Example 2

Add 500ml of distilled water at 0°C to a 1000ml flask, slowly add 25g of TiCl ₄ (analytical pure) under vigorous stirring, the weight ratio of water to titanium tetrachloride is 10:0.5, and electromagnetically stir at room temperature (20-30°C) 3h; Pour the obtained milky white slurry into a single-necked flask, seal it, put it in a drying oven at 80°C for crystallization for 2 days, and pour the supernatant after standing still; wash the lower layer with 200ml of water, then pour the supernatant after standing still, The slurry was suction filtered and washed with distilled water several times until the pH value was 3; the filter cake was transferred to a beaker and 200ml of distilled water was added, that is, the weight ratio of the added water to titanium tetrachloride was 8:1, dispersed by electromagnetic stirring for 1.5h, and finally ultrasonically After dispersing for 1 hour, the rutile phase nano-titanium dioxide dispersion slurry can be obtained, the content of titanium dioxide in the slurry is 5%, and the stability is more than 2 months.

Example 3

Add 500ml of distilled water at 0°C (mixed with ice and water) into a 1000ml flask, slowly add 100g TiCl ₄ (analytical pure) under vigorous stirring, the weight ratio of water to titanium tetrachloride is 10:2, room temperature (20-30 ℃) under electromagnetic stirring for 3 hours; pour the obtained milky white slurry into a single-necked flask, seal it and put it in a drying oven at 50 ℃ for crystallization for 3 days, and then pour the supernatant liquid after static; wash the lower layer with 500ml water and then static to Pour the supernatant, filter the slurry and wash it with distilled water for several times until the pH value is 1.5; transfer the filter cake to a beaker and add 100ml of distilled water, that is, the weight ratio of the added water to titanium tetrachloride is 1:1, and disperse with electromagnetic stirring 1 hour, and finally ultrasonically disperse for 2 hours to obtain the rutile phase nano-titanium dioxide dispersion slurry, the content of titanium dioxide in the slurry is 30%, and the stability is more than 2 months.

Claims (1)

1, a kind of preparation method of rutile-phase nano-titanium dioxide dispersed paste is characterized in that comprising the steps:

(1) in 0 ℃ water, stir adding titanium tetrachloride down, the weight ratio of water and titanium tetrachloride is 10: (0.1～3);

(2) induction stirring hydrolysis 2～5h under the room temperature obtains the hydrolysis slurry;

(3) with the hydrolysis slurry 25～80 ℃ of following crystallization, crystallization time 2～3 days, its structural transformation becomes the rutile phase structure;

(4) topple over supernatant liquid after the hydrolysis slurry that will be transformed into the rutile phase structure leaves standstill, it is 1～4 that lower floor's slurries wash with water until pH value;

(5) lower floor's slurries are added water, its weight ratio that adds entry and titanium tetrachloride is (1.0～8): 1; Induction stirring is disperseed 0.5～2h, and ultra-sonic dispersion 1～2h obtains the rutile-phase nano-titanium dioxide dispersed paste then.