Superfine high-dispersion type nano TiO2 as well as preparation method and application thereof

Abstract

The invention discloses superfine high-dispersion type nano TiO2 as well as a preparation method and application thereof, and the preparation method of the superfine high-dispersion type nano TiO2 comprises the following steps: adding a TiCl4 solution into a base solution containing ammonium polycarboxylate, polyether modified siloxane and ammonia water, and carrying out coprecipitation reaction to prepare the nano TiO2. According to the preparation method, through the synergistic effect among ammonium polycarboxylate, polyether modified siloxane and ammonia water in the base solution, nano TiO2 which is good in dispersity, uniform in particle size, spherical in microstructure, 5-10 nm in particle size and has a mixed phase of a rutile phase and an anatase phase is prepared, the preparation process is mild in reaction condition, simple in equipment requirement, short in process route and suitable for industrial production, and the preparation method is suitable for industrial production. The industrial production is easy, and the application field of the superfine high-dispersion type nano TiO2 is greatly widened.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of nano-TiO2, in particular to superfine high-dispersion nano-TiO2, a preparation method and application thereof. BACKGROUND

[0003] At present, the preparation methods of TiO2 mainly include gas phase reaction method, solid phase reaction method and liquid phase reaction method. The gas phase method has high production cost due to high temperature in the process and serious corrosion of the equipment by by-products. The solid phase method has simple preparation process, but the obtained TiO2 has wide particle size distribution and extremely rough material quality. The liquid phase method has the advantages of both and avoids the disadvantages, has mild reaction conditions, simple equipment requirements and low cost, and is suitable for industrial production.

[0004] The particle size, morphology, crystal structure and purity of TiO2 have a profound influence on its performance. The nano-material has excellent photoelectric performance, and the smaller the particle size, the more prominent the performance. The special structure of superfine high-dispersion TiO2 makes it have excellent performance in the fields of dielectric, electron transport and photocatalysis. Therefore, the superfine high-dispersion nano-TiO2 has great practical significance in the fields of dielectric materials and photocatalysis.

[0005] CN105967229A discloses a method for preparing rod-shaped titanium dioxide, which comprises the following steps: preparing a solution by mixing a titanium source and an organic solvent, stirring uniformly, pouring into a reaction kettle, hydrothermal reaction at 60-300 DEG C for 6-36 hours, centrifugal washing of the hydrothermal product with deionized water or ethanol, and finally drying and calcining the product. The method needs high reaction temperature and long holding time, greatly increasing the cost of industrial production. In addition, high pressure and high temperature are also strict requirements for the equipment, and the use and treatment process of organic matter in the production process increase the cost and damage the environment.

[0006] CN105016382A discloses a method for preparing rutile-type nano-TiO2 with controllable morphology under normal pressure and low temperature environment, using water as a dispersion medium, and using an iron-containing crystal type control agent at a mass fraction of 0.5%-50% of the titanium source. Although the method uses normal pressure and low temperature production process, it has obvious effect on reducing the cost and requirements of the equipment, but the use of iron-containing crystal type control agent introduces metal impurities into the product, and the existence of iron impurities greatly limits the application range of the product TiO2. SUMMARY

[0007] The present application aims to overcome the above-mentioned deficiencies in the prior art, and provides superfine high-dispersion nano-TiO2, a preparation method and application thereof.

[0008] The present application solves its technical problems by adopting the following technical scheme.

[0009] The present application provides a kind of superfine high dispersion type nano TiO2, the microtopography of superfine high dispersion type nano TiO2 is spherical, particle size is 5nm-10nm, and it has the mixed phase of rutile phase and anatase phase.

[0010] The present application also provides a kind of preparation method of the above-mentioned superfine high dispersion type nano TiO2, which comprises: using TiCl4 as titanium source, pure water as reaction medium, by adding polycarboxylic acid ammonium, polyether modified siloxane and ammonia, using coprecipitation method, superfine high dispersion type nano TiO2 is prepared.

[0011] The present application also provides a kind of superfine high dispersion type nano TiO2 or the application of superfine high dispersion type nano TiO2 prepared by the above-mentioned preparation method in dielectric field, electron transport, photocatalysis, cosmetics and new energy battery.

[0012] The present application has the following beneficial effects: The present application provides superfine high dispersion type nano TiO2 and its preparation method and application, the present application is prepared by adding TiCl4 solution in the bottom liquid containing polycarboxylic acid ammonium, polyether modified siloxane and ammonia, and then reacting to obtain nano TiO2.TiO2 prepared by the synergistic effect between polycarboxylic acid ammonium, polyether modified siloxane and ammonia, the whole preparation process is simple, the reaction condition is mild, the prepared superfine high dispersion type nano TiO2 has good dispersibility, uniform particle size, particle size is 5nm-10nm, and it has the mixed phase of rutile phase and anatase phase, which greatly widens the application field of TiO2. BRIEF DESCRIPTION OF DRAWINGS

[0013] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.

[0014] Figure 1 SEM diagram of superfine high dispersion type nano TiO2 prepared for example 4; Figure 2 XRD diagram of superfine high dispersion type nano TiO2 prepared for example 4. DETAILED DESCRIPTION

[0015] In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below. If the specific conditions are not specified in the embodiments, the conventional conditions or the conditions suggested by the manufacturers are adopted. If the manufacturers of the reagents or instruments are not specified, the conventional products that can be purchased in the market are adopted.

[0016] The ultrafine high-dispersity nano-TiO2 provided by the embodiments of the present application, the preparation method thereof and the application thereof will be described in detail below.

[0017] In the first aspect, the embodiments of the present application provide an ultrafine high-dispersity nano-TiO2. The micro-morphology of the ultrafine high-dispersity nano-TiO2 is spherical, the particle size is 5nm-10nm, and the mixed phase of rutile phase and anatase phase is possessed.

[0018] The embodiments of the present application provide an ultrafine high-dispersity nano-TiO2. The micro-morphology of the ultrafine high-dispersity nano-TiO2 is spherical, the particle size is 5nm-10nm, and the mixed phase of rutile phase and anatase phase is possessed.

[0019] In some optional embodiments, the proportion of the rutile phase in the mixed phase is 2-15%, and the specific surface area is 150-320m 2 / g.

[0020] In the second aspect, the embodiments of the present application provide a preparation method of the above-mentioned ultrafine high-dispersity nano-TiO2. The preparation method comprises the following steps: taking TiCl4 as a titanium source and pure water as a reaction medium, adding polycarboxylic acid ammonium, polyether modified siloxane and ammonia water, and adopting a co-precipitation method to prepare the ultrafine high-dispersity nano-TiO2.

[0021] In some optional embodiments, the preparation method comprises the following steps: adding a TiCl4 solution into a base solution containing pure water, polycarboxylic acid ammonium, polyether modified siloxane and ammonia water to perform a co-precipitation reaction, and preparing the ultrafine high-dispersity nano-TiO2. Preferably, the preparation method comprises the following steps: preparing a base solution containing pure water, polycarboxylic acid ammonium, polyether modified siloxane and ammonia water, adding the TiCl4 solution into the base solution drop by drop, performing aging and crystal growth after the feeding is completed, and then performing post-treatment to prepare the 5nm-10nm ultrafine high-dispersity nano-TiO2.

[0022] The embodiment of the present application provides a preparation method of superfine high-dispersed nano TiO2, aiming at solving the problems of large particles, serious material agglomeration, single crystal phase, low activity and high Cl impurity content. TiCl4 solution is added into a base solution containing polycarboxylic acid ammonium, polyether modified siloxane and ammonia water, and the dispersants (polycarboxylic acid ammonium and polyether modified siloxane) in the base solution not only play the role of dispersion and inhibition of particle agglomeration and regeneration, but also have a synergistic complementary enhancement effect. Specifically: The carboxyl groups in the polycarboxylic acid ammonium can form chemical bonds with the hydroxyl groups on the surface of TiO2, increase the surface negative charge through chemical adsorption, improve the electrostatic repulsion, and prevent particle agglomeration. And the ammonium ions in the polycarboxylic acid ammonium can provide lone pair electrons, attract Ti 4+ , form a space network structure, avoid the phenomenon of large crystal grains "swallowing" small crystal grains, and inhibit the regeneration of particles. However, polycarboxylic acid ammonium easily introduces bubbles due to the carboxyl and ammonium groups in the molecular structure, which increases the difficulty and risk of the synthesis process. Polyether modified siloxane has dynamic defoaming ability, the hydrophobic siloxane segment can break the bubble film, and the hydrophilic polyether segment can inhibit the regeneration of foam. The use of polycarboxylic acid ammonium and polyether modified siloxane can eliminate harmful large bubbles. At the same time, due to the large fluctuation of pH during the preparation of nano TiO2: the proportion of ammonia water is high at the beginning of the reaction, pH=11, and the proportion of by-product HCl is high at the end of the reaction, pH<1, a single dispersant is easily disabled under high ionic strength, and the use of a mixed dispersant of polycarboxylic acid ammonium and polyether modified siloxane can form a double electric layer and steric hindrance, solve the problem of single dispersant failure in acid and alkali environment, and expand the pH coverage range in the production process.

[0023] The ammonia water in the base solution can accelerate the formation of crystal nucleus, adjust the crystal type (anatase / rutile) and particle size distribution. And the ammonia water in the system is ionized into NH 4+ and OH - , making the solution weakly alkaline, which can promote the increase of the ionization degree of the carboxyl groups in the polycarboxylic acid ammonium, make the molecular chain stretch more fully, enhance the electrostatic repulsion, and further promote the dispersion of the polycarboxylic acid ammonium. However, the addition of ammonia water may react with polycarboxylic acid ammonium to release ammonia, which may cause bubbles in the system, increase the complexity of process control and safety risks caused by ammonia accumulation. The use of polyether modified siloxane solves this problem. On the other hand, the OH - in the ammonia water can be combined with the hydrogen bond of the polyether segment to form a molecular brush structure at the interface, locally enriching TiO2 molecules. And it can promote the increase of the ionization degree of the EO / PO segment of polyether modified siloxane, make the molecular chain stretch more fully, enhance the steric hindrance effect, improve the dispersion stability, and further improve the dispersion capacity of polyether modified siloxane.

[0024] In some alternative embodiments, the preparation of the TiCl4 solution comprises the following steps: adding pure water into a container with a condensing jacket, and starting stirring, slowly dropping pure TiCl4 into the container, and after the dropping is completed, dispersing under stirring. Preferably, the temperature of the container is controlled below 25℃, the dropping speed of the pure TiCl4 is 8-15 L / min, the mass ratio of the pure TiCl4 to the pure water is 1:1-2.3, after the dropping is completed, the stirring is performed for 30 min, and a TiCl4 solution with a mass concentration of 30-50% is obtained.

[0025] In some alternative embodiments, the preparation of the bottom solution comprises the following steps: adding pure water, polycarboxylic acid ammonium and polyether modified siloxane into a reaction kettle, continuously stirring at room temperature, and fully dissolving, and adding ammonia water 10 min before the reaction. Preferably, the mass ratio of the pure water, the polycarboxylic acid ammonium and the polyether modified siloxane, and the ammonia water in the bottom solution is controlled to be 1:0.01-0.10:0.001-0.01. Preferably, the mass ratio of the polycarboxylic acid ammonium to the polyether modified siloxane in the bottom solution is 1:0.1-0.5.

[0026] In some alternative embodiments, the feeding mode comprises: dropping the TiCl4 solution into the bottom solution in the reaction kettle, maintaining the temperature in the reaction kettle at 15-35℃, and after the feeding is completed, fully stirring for 30 min. Preferably, the dropping speed of the TiCl4 solution is controlled to be 20-33 L / min.

[0027] In some alternative embodiments, the aging and crystal growing comprises: after the feeding is completed, opening the cold cycle of the reaction kettle, stabilizing the temperature at 5-25℃, and stopping the stirring for 1 h to make the crystals uniformly precipitate.

[0028] In some alternative embodiments, the post-treatment comprises: sequentially performing solid-liquid coarse separation, purification and drying treatment on the slurry after the aging and crystal growing.

[0029] In some alternative embodiments, the post-processing includes the following steps: discharging the supernatant from the aged and crystallized slurry, diluting the remaining concentrated solution in the reactor with pure water, concentrating and purifying using a ceramic membrane, concentrating while adding pure water, until the conductivity reaches below 50 us / cm, and then performing spray drying to obtain ultra-fine and highly dispersed nano-TiO2. When the aged and crystallized slurry is subjected to solid-liquid separation and ceramic membrane purification, water is added and stirred after the solid-liquid coarse separation to further dilute the solid content of the slurry, so as to avoid clogging the ceramic membrane. During each ceramic membrane washing process, 5-10 times of pure water is added. The addition of water can effectively reduce the content of chlorine and other water-soluble impurities, and finally control the conductivity of TiO2 in the water discharged by pressure filtration to be within 50 us / cm. The concentrated solution is sprayed and dried using a spray dryer, and finally 5-10 nm ultra-fine and highly dispersed nano-TiO2 is obtained.

[0030] As can be seen from the above, the embodiment of the present application provides a preparation method of ultra-fine and highly dispersed nano-TiO2, which uses TiCl4 as a titanium source and water as a medium. By adding ammonium polycarboxylate, polyether modified siloxane and ammonia, nano-titanium dioxide with spherical micro-morphology, good dispersibility, particle size of 5-10 nm, high activity and mixed phase of rutile phase and anatase phase is prepared by using a co-precipitation method. The entire preparation process has low production cost, simple equipment requirement and mild reaction conditions, and can realize industrialized scale production.

[0031] In a third aspect, the embodiment of the present application provides the application of the above-mentioned ultra-fine and highly dispersed nano-TiO2 or the ultra-fine and highly dispersed nano-TiO2 prepared by the above-mentioned preparation method in the fields of dielectric, electron transport, photocatalysis, cosmetics and new energy batteries.

[0032] The ultra-fine and highly dispersed nano-TiO2, the preparation method and the application thereof provided by the present application will be described in detail below in conjunction with embodiments, but they should not be understood as limiting the scope of protection of the present application.

[0033] The ammonium polycarboxylate used in the following examples and comparative examples is ammonium polycarboxylate SN-5468 from Japan Sankonuo, with a solid content of 40.5%. The polyether modified siloxane used is from Shanghai Maikelin Biochemical Technology Co., Ltd., with a molecular weight of 338.663.

[0034] Example 1 (1) Preparation of TiCl4 solution: add pure water to a porcelain kettle with a condensing jacket, start the condensing water, and add pure TiCl4 solution to the porcelain kettle while stirring, with the mass ratio of TiCl4 to pure water being 1:1, and the dropwise addition speed being controlled at 8 L / min. After the addition is completed, stir for 30 min for standby.

[0035] (2) The configuration of the reactor bottom liquid: pure water, polyammonium carboxylate, and polyether modified siloxane (the mass ratio of polyammonium carboxylate to polyether modified siloxane is 1:0.5) are added to the reactor, and constant stirring is carried out at room temperature to fully dissolve. 10 minutes before the reaction, ammonia water is added. The mass ratio of pure water, polyammonium carboxylate, polyether modified siloxane, and ammonia water is 1:0.01:0.001.

[0036] (3) Feeding method: use a pneumatic diaphragm pump to pour the TiCl4 solution into the reactor at a certain flow rate. The temperature of the reactor is always controlled between 15°C. After feeding is completed, fully stir for 30 minutes.

[0037] (4) Aging and crystal growth: open the cold cycle of the reactor, and stabilize the temperature at 5°C. Turn off the stirring and stand still for 1 hour to make the crystals uniformly precipitate.

[0038] (5) Solid-liquid coarse separation: the supernatant after standing is pumped out, and the precipitated crystals are separated from the mother liquor.

[0039] (6) Purification: dilute the concentrated liquid in the reactor with pure water, and then use a ceramic membrane to concentrate and purify. Add pure water while concentrating until the conductivity reaches below 50 us / cm.

[0040] (7) Spray drying: use a spray dryer to spray dry the concentrated liquid to obtain ultrafine and highly dispersed nano-TiO2.

[0041] Example 2 (1) TiCl4 solution configuration: add pure water to a porcelain reactor with a condenser jacket, start the condenser water, and drop pure TiCl4 solution into the porcelain reactor while stirring. The mass ratio of TiCl4 to pure water is 1:2.3, and the dropping speed is controlled at 8 L / min. After the addition is completed, stir for 30 minutes for standby.

[0042] (2) The configuration of the reactor bottom liquid: pure water, polyammonium carboxylate, and polyether modified siloxane (the mass ratio of polyammonium carboxylate to polyether modified siloxane is 1:0.5) are added to the reactor, and constant stirring is carried out at room temperature to fully dissolve. 10 minutes before the reaction, ammonia water is added. The mass ratio of pure water, polyammonium carboxylate, polyether modified siloxane, and ammonia water is 1:0.01:0.001.

[0043] (3) Feeding method: use a pneumatic diaphragm pump to pour the TiCl4 solution into the reactor at a certain flow rate. The temperature of the reactor is always controlled between 25°C. After feeding is completed, fully stir for 30 minutes.

[0044] (4) Aging and crystal growth: open the cold cycle of the reactor, and stabilize the temperature at 5°C. Turn off the stirring and stand still for 1 hour to make the crystals uniformly precipitate.

[0045] (5) Solid-liquid coarse separation: the supernatant after standing is pumped out, and the precipitated crystals are separated from the mother liquor.

[0046] (6) Purification: the concentrated solution in the reaction kettle is diluted with pure water, and then concentrated and purified using a ceramic membrane. The conductivity is reduced to below 50 us / cm by adding pure water while concentrating.

[0047] (7) Spray drying: the concentrated solution is spray dried using a spray dryer to obtain ultrafine and highly dispersed nano-TiO2.

[0048] Example 3 (1) TiCl4 solution preparation: pure water is added to a porcelain kettle with a condensing jacket, and the condensing water is turned on. While stirring, pure TiCl4 solution is added dropwise to the porcelain kettle at a mass ratio of TiCl4 to pure water of 1:1, and the dropwise addition rate is controlled at 15 L / min. After the addition is completed, stirring is continued for 30 min for standby.

[0049] (2) Preparation of reaction kettle bottom liquid: pure water, ammonium polycarboxylate, and polyether-modified siloxane (mass ratio of ammonium polycarboxylate to polyether-modified siloxane is 1:0.1) are added to the reaction kettle, and stirring is continued at room temperature to ensure complete dissolution. Ammonia is added 10 min before the reaction, and the mass ratio of pure water to ammonium polycarboxylate, polyether-modified siloxane, and ammonia is 1:0.01:0.001.

[0050] (3) Feeding method: a pneumatic diaphragm pump is used to feed the TiCl4 solution into the reaction kettle at a certain flow rate. The temperature of the reaction kettle is always controlled between 35°C, and the stirring is continued for 30 min after the feeding is completed.

[0051] (4) Aging and crystal growth: the reaction kettle is opened for cold circulation, and the temperature is stabilized at 25°C. The stirring is turned off and the crystals are allowed to precipitate uniformly for 1 h.

[0052] (5) Solid-liquid coarse separation: the supernatant after standing is pumped out, and the precipitated crystals are separated from the mother liquor.

[0053] (6) Purification: the concentrated solution in the reaction kettle is diluted with pure water, and then concentrated and purified using a ceramic membrane. The conductivity is reduced to below 30 us / cm by adding pure water while concentrating.

[0054] (7) Spray drying: the concentrated solution is spray dried using a spray dryer to obtain ultrafine and highly dispersed nano-TiO2.

[0055] Example 4 (1) TiCl4 solution configuration: add pure water to the enamel kettle with condenser jacket, open the condenser water, while stirring, drop pure TiCl4 solution into the enamel kettle, the mass ratio of TiCl4 to pure water is 1:1, the drop speed is controlled at 10L / min. After the addition is completed, stir for 30 min for standby.

[0056] (2) Configuration of reactor bottom liquid: add pure water, polycarboxylic acid ammonium and polyether modified siloxane (the mass ratio of polycarboxylic acid ammonium to polyether modified siloxane is 1:0.1) into the reactor, continuously stir at room temperature, fully dissolve, add ammonia water 10 min before reaction, the mass ratio of pure water: polycarboxylic acid ammonium, polyether modified siloxane: ammonia water is 1:0.1:0.001.

[0057] (3) Feeding method: use pneumatic diaphragm pump to feed TiCl4 solution into the reactor at a certain flow rate, the temperature of the reactor is always controlled between 20℃, after the feeding is completed, stir for 30 min.

[0058] (4) Aging and crystal growth: open the cold cycle of the reactor, stabilize the temperature at 15℃, turn off the stirring and stand for 1h to make the crystals uniformly precipitate.

[0059] (5) Solid-liquid coarse separation: after standing and aging, the supernatant is pumped out, and the precipitated crystals are separated from the mother liquor.

[0060] (6) Purification: dilute the concentrated liquid in the reactor with pure water, then use ceramic membrane for concentration and purification, add pure water while concentrating until the conductivity reaches below 30us / cm.

[0061] (7) Spray drying: use spray dryer to spray dry the concentrated liquid to obtain ultrafine and highly dispersed nano TiO2. The SEM and XRD images of the prepared ultrafine and highly dispersed nano TiO2 are shown in Figure 1 and Figure 2 .

[0062] Example 5 (1) TiCl4 solution configuration: add pure water to the enamel kettle with condenser jacket, open the condenser water, while stirring, drop pure TiCl4 solution into the enamel kettle, the mass ratio of TiCl4 to pure water is 1:1.5, the drop speed is controlled at 10L / min. After the addition is completed, stir for 30 min for standby.

[0063] (2) Configuration of reactor bottom liquid: add pure water, polycarboxylic acid ammonium and polyether modified siloxane (the mass ratio of polycarboxylic acid ammonium to polyether modified siloxane is 1:0.25) into the reactor, continuously stir at room temperature, fully dissolve, add ammonia water 10 min before reaction, the mass ratio of pure water: polycarboxylic acid ammonium, polyether modified siloxane: ammonia water is 1:0.05:0.01.

[0064] (3) Feeding method: use the pneumatic diaphragm pump to pour the TiCl4 solution into the reactor at a certain flow rate, the temperature of the reactor is always controlled between 20°C, after the feeding is completed, fully stir for 30 min.

[0065] (4) Aging and crystal growth: open the cold cycle of the reactor, the temperature is stabilized at 15°C, close the stirring and stand for 1 h, so that the crystals are uniformly precipitated.

[0066] (5) Solid-liquid coarse separation: the supernatant after standing is pumped out, and the precipitated crystals are separated from the mother liquor.

[0067] (6) Purification: the concentrated solution in the reactor is diluted with pure water, then concentrated using a ceramic membrane, and the conductivity is below 30 us / cm.

[0068] (7) Spray drying: use a spray dryer to spray dry the concentrated solution to obtain ultrafine and highly dispersed nano-TiO2.

[0069] Example 6 (1) Preparation of TiCl4 solution: add pure water to a porcelain reactor with a condenser jacket, start the condenser water, and add pure TiCl4 solution to the porcelain reactor while stirring, the mass ratio of TiCl4 to pure water is 1:1.5, the dropwise addition speed is controlled at 10 L / min. After the feeding is completed, stir for 30 min for standby.

[0070] (2) Preparation of reactor bottom liquid: add pure water, polyammonium carboxylate, and polyether modified siloxane (the mass ratio of polyammonium carboxylate to polyether modified siloxane is 1:0.4) to the reactor, continuously stir at room temperature, fully dissolve, and then add ammonia water 10 min before reaction, the mass ratio of pure water: polyammonium carboxylate: polyether modified siloxane: ammonia water is 1:0.05:0.005.

[0071] (3) Feeding method: use the pneumatic diaphragm pump to pour the TiCl4 solution into the reactor at a certain flow rate, the temperature of the reactor is always controlled between 20°C, after the feeding is completed, fully stir for 30 min.

[0072] (4) Aging and crystal growth: open the cold cycle of the reactor, the temperature is stabilized at 10°C, close the stirring and stand for 1 h, so that the crystals are uniformly precipitated.

[0073] (5) Solid-liquid coarse separation: the supernatant after standing is pumped out, and the precipitated crystals are separated from the mother liquor.

[0074] (6) Purification: the concentrated solution in the reactor is diluted with pure water, then concentrated using a ceramic membrane, and the conductivity is below 30 us / cm.

[0075] (7) Spray drying: using a spray dryer, the concentrated liquid is spray dried to obtain ultra-fine high dispersion type nano-TiO2.

[0076] Comparative Example 1 (1) Preparation of TiCl4 solution: add pure water to a porcelain kettle with a condensing jacket, start the condensing water, and drop pure TiCl4 solution into the porcelain kettle while stirring, the mass ratio of TiCl4 to pure water is 1:1, and the dropping speed is controlled at 10 L / min. After the feeding is completed, stir for 30 min for standby.

[0077] (2) Preparation of reaction kettle bottom liquid: add pure water and polycarboxylic acid ammonium to the reaction kettle, continuously stir at room temperature, fully dissolve, and then add ammonia water 10 min before reaction, the mass ratio of pure water: polycarboxylic acid ammonium: ammonia water is 1:0.01:0.001.

[0078] (3) Feeding method: use a pneumatic diaphragm pump to feed the TiCl4 solution into the reaction kettle at a certain flow rate, the temperature of the reaction kettle is always controlled between 20°C, and after the feeding is completed, stir for 30 min.

[0079] (4) Aging and crystal growth: open the cold cycle of the reaction kettle, and stabilize the temperature at 15°C, turn off the stirring and stand for 1 h to make the crystals uniformly precipitate.

[0080] (5) Solid-liquid coarse separation: the supernatant after standing is pumped out, and the precipitated crystals are separated from the mother liquor.

[0081] (6) Purification: dilute the concentrated liquid in the reaction kettle with pure water, and then use a ceramic membrane to concentrate and purify, add pure water while concentrating until the conductivity reaches below 30 us / cm.

[0082] (7) Spray drying: use a spray dryer to spray dry the concentrated liquid to obtain TiO2.

[0083] Comparative Example 2 (1) Preparation of TiCl4 solution: add pure water to a porcelain kettle with a condensing jacket, start the condensing water, and drop pure TiCl4 solution into the porcelain kettle while stirring, the mass ratio of TiCl4 to pure water is 1:1, and the dropping speed is controlled at 10 L / min. After the feeding is completed, stir for 30 min for standby.

[0084] (2) Preparation of reaction kettle bottom liquid: add pure water and polyether modified siloxane to the reaction kettle, continuously stir at room temperature, fully dissolve, and then add ammonia water 10 min before reaction, the mass ratio of pure water: polyether modified siloxane: ammonia water is 1:0.01:0.001.

[0085] (3) Feeding method: use the pneumatic diaphragm pump to pour the TiCl4 solution into the reactor at a certain flow rate, the temperature of the reactor is always controlled between 20°C, after the feeding is completed, fully stir for 30 min.

[0086] (4) Aging and crystal growth: open the cold cycle of the reactor, stabilize the temperature at 15°C, close the stirring and stand for 1 h, so that the crystals are uniformly precipitated.

[0087] (5) Solid-liquid coarse separation: the supernatant after standing is pumped out, and the precipitated crystals are separated from the mother liquor.

[0088] (6) Purification: the concentrated solution in the reactor is diluted with pure water, and then concentrated by ceramic membrane, and the conductivity is below 30 us / cm.

[0089] (7) Spray drying: use a spray dryer to spray dry the concentrated solution to obtain TiO2.

[0090] Comparative Example 3 (1) Preparation of TiCl4 solution: add pure water to a porcelain reactor with a condenser jacket, open the condenser water, and add pure TiCl4 solution to the porcelain reactor while stirring, the mass ratio of TiCl4 to pure water is 1:1, the dropwise adding speed is controlled at 10 L / min. After the feeding is completed, stir for 30 min for standby.

[0091] (2) Preparation of reactor bottom liquid: add pure water, polyammonium carboxylate and polyvinylpyrrolidone (PVP) (the mass ratio of polyammonium carboxylate to PVP is 1:0.5) to the reactor, continuously stir at room temperature, fully dissolve, and then add ammonia water 10 min before reaction, the mass ratio of pure water: polyammonium carboxylate: PVP: ammonia water is 1:0.1:0.001.

[0092] (3) Feeding method: use the pneumatic diaphragm pump to pour the TiCl4 solution into the reactor at a certain flow rate, the temperature of the reactor is always controlled between 20°C, after the feeding is completed, fully stir for 30 min.

[0093] (4) Aging and crystal growth: open the cold cycle of the reactor, stabilize the temperature at 15°C, close the stirring and stand for 1 h, so that the crystals are uniformly precipitated.

[0094] (5) Solid-liquid coarse separation: the supernatant after standing is pumped out, and the precipitated crystals are separated from the mother liquor.

[0095] (6) Purification: the concentrated solution in the reactor is diluted with pure water, and then concentrated by ceramic membrane, and the conductivity is below 30 us / cm.

[0096] (7) Spray drying: using a spray dryer, the concentrated liquid is spray dried to obtain TiO2.

[0097] Comparative Example 4 (1) TiCl4 solution preparation: add pure water into the enamel kettle with condensing jacket, open the condensing water, while stirring, add pure TiCl4 solution into the enamel kettle, the mass ratio of TiCl4 to pure water is 1:1, the drop speed is controlled at 10 L / min. After the addition is completed, stir for 30 min for standby.

[0098] (2) Reaction kettle bottom liquid preparation: add pure water, polyethylene glycol and polyether modified siloxane into the reaction kettle (the mass ratio of polyethylene glycol to polyether modified siloxane is 1:0.1), continuously stir at room temperature, fully dissolve, then add ammonia water 10 min before the reaction, the mass ratio of pure water, polyethylene glycol, polyether modified siloxane and ammonia water is 1:0.1:0.001.

[0099] (3) Feeding method: use the pneumatic diaphragm pump to feed the TiCl4 solution into the reaction kettle at a certain flow rate, the temperature of the reaction kettle is always controlled at 20℃, after the feeding is completed, fully stir for 30 min.

[0100] (4) Aging and crystal growth: open the cold cycle of the reaction kettle, the temperature is stabilized at 15℃, stop stirring for 1 h to make the crystals uniformly precipitate.

[0101] (5) Solid-liquid coarse separation: the supernatant after aging and standing is pumped out, the precipitated crystals are separated from the mother liquor.

[0102] (6) Purification: dilute the concentrated liquid in the reaction kettle with pure water, then use the ceramic membrane to concentrate and purify, while adding pure water, concentrate until the conductivity is below 30 us / cm.

[0103] (7) Spray drying: use the spray dryer to spray dry the concentrated liquid to obtain TiO2.

[0104] Comparative Example 5 (1) TiCl4 solution preparation: add pure water into the enamel kettle with condensing jacket, open the condensing water, while stirring, add pure TiCl4 solution into the enamel kettle, the mass ratio of TiCl4 to pure water is 1:1, the drop speed is controlled at 10 L / min. After the addition is completed, stir for 30 min for standby.

[0105] (2) Reaction kettle bottom liquid preparation: add pure water, polyether modified siloxane and polyether modified siloxane into the reaction kettle (the mass ratio of polyether modified siloxane to polyether modified siloxane is 1:1), continuously stir at room temperature, fully dissolve, then add ammonia water 10 min before the reaction, the mass ratio of pure water, polyether modified siloxane and ammonia water is 1:0.1:0.001.

[0106] (3) Feeding method: use the pneumatic diaphragm pump to pour the TiCl4 solution into the reactor at a certain flow rate, the temperature of the reactor is always controlled between 20°C, after the feeding is completed, fully stir for 30 min.

[0107] (4) Aging and crystal growth: open the cold cycle of the reactor, stabilize the temperature at 15°C, close the stirring and stand for 1 h, so that the crystals are uniformly precipitated.

[0108] (5) Solid-liquid coarse separation: the supernatant after standing is pumped out, and the precipitated crystals are separated from the mother liquor.

[0109] (6) Purification: the concentrated solution in the reactor is diluted with pure water, then concentrated by ceramic membrane, and the conductivity is below 30 us / cm.

[0110] (7) Spray drying: use a spray dryer to spray dry the concentrated solution to obtain TiO2.

[0111] Comparative Example 6 (1) Preparation of TiCl4 solution: add pure water to a porcelain reactor with a condenser jacket, open the condenser water, and add pure TiCl4 solution to the porcelain reactor while stirring, the mass ratio of TiCl4 to pure water is 1:1, the dropwise addition speed is controlled at 10 L / min. After the addition is completed, stir for 30 min for standby.

[0112] (2) Preparation of reactor bottom liquid: add pure water, polyammonium carboxylate and polyether modified siloxane (the mass ratio of polyammonium carboxylate to polyether modified siloxane is 1:0.4) to the reactor, continuously stir at room temperature, fully dissolve, and then add ammonia water 10 min before reaction, the mass ratio of pure water: polyammonium carboxylate, polyether modified siloxane: ammonia water is 1:0.1:1.

[0113] (3) Feeding method: use the pneumatic diaphragm pump to pour the TiCl4 solution into the reactor at a certain flow rate, the temperature of the reactor is always controlled between 20°C, after the feeding is completed, fully stir for 30 min.

[0114] (4) Aging and crystal growth: open the cold cycle of the reactor, stabilize the temperature at 15°C, close the stirring and stand for 1 h, so that the crystals are uniformly precipitated.

[0115] (5) Solid-liquid coarse separation: the supernatant after standing is pumped out, and the precipitated crystals are separated from the mother liquor.

[0116] (6) Purification: the concentrated solution in the reactor is diluted with pure water, then concentrated by ceramic membrane, and the conductivity is below 30 us / cm.

[0117] (7) Spray drying: using a spray dryer, the concentrated liquid is spray dried to obtain TiO2.

[0118] The evaluation results of the ultrafine and highly dispersed nano-TiO2 prepared by the examples and the comparative examples of the present application are shown in the following table:

[0119] As can be seen from the above table, the ultrafine and highly dispersed nano-TiO2 prepared by the scheme provided by the examples of the present application has a spherical micro-morphology, a particle size of 5-10 nm, and a mixed phase of rutile phase and anatase phase, wherein the rutile phase accounts for 2-15% of the mixed phase, the specific surface area is 150-320 m2 / g, and the Cl content is low. 2 In the comparative examples, only one dispersant is used, or the type and amount of the dispersant in the preparation system is changed, and the morphology, particle size, specific surface area and dispersibility of the obtained nano-TiO2 are not as good as those of the examples, in addition, there are defects of high rutile phase content and high Cl content.

[0120] The above is only the preferred embodiments of the present application and is not used to limit the present application, and for those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. An ultrafine, highly dispersed nano-TiO2, characterized in that, The ultrafine, highly dispersed nano-TiO2 has a spherical morphology with a particle size of 5 nm to 10 nm, and is a mixed phase of rutile and anatase phases.

2. The ultrafine, highly dispersed nano-TiO2 according to claim 1, characterized in that, The rutile phase in the mixed phase of the ultrafine, highly dispersed nano-TiO2 accounts for 2-15%, and the specific surface area is 150-320 m². 2 / g.

3. A method for preparing ultrafine, highly dispersed nano-TiO2 according to claim 1 or 2, characterized in that, It includes: Using TiCl4 as the titanium source and pure water as the reaction medium, ultrafine, highly dispersed nano-TiO2 was prepared by co-precipitation method by adding ammonium polycarboxylate, polyether-modified siloxane and ammonia.

4. The preparation method according to claim 3, characterized in that, It includes: adding TiCl4 solution to a base solution containing pure water, ammonium polycarboxylate, polyether-modified siloxane and ammonia, and carrying out a co-precipitation reaction to obtain ultrafine highly dispersed nano-TiO2; Preferably, the method includes the following steps: preparing a base solution containing pure water, ammonium polycarboxylate, polyether-modified siloxane and ammonia, adding TiCl4 solution dropwise to the base solution, aging and growing crystals after the feeding is completed, and then performing post-treatment to obtain 5nm-10nm ultrafine highly dispersed nano-TiO2.

5. The preparation method according to claim 4, characterized in that, The preparation of the TiCl4 solution includes the following steps: adding pure water to a container with a condenser jacket and turning on the stirrer; slowly dripping pure TiCl4 into the container; and stirring to disperse the solution after the addition is complete. Preferably, the container temperature is controlled below 25°C, the dropping rate of the pure TiCl4 is 8-15 L / min, the mass ratio of the pure TiCl4 to the pure water is 1:1-2.3, and after the addition is complete, the mixture is stirred for 30 min to obtain a TiCl4 solution with a mass concentration of 30-50%.

6. The preparation method according to claim 4, characterized in that, The preparation of the base liquid includes the following steps: adding pure water, ammonium polycarboxylate and polyether-modified siloxane to the reaction vessel, stirring continuously at room temperature to fully dissolve, and adding ammonia water 10 minutes before the co-precipitation reaction; Preferably, the mass ratio of pure water, ammonium polycarboxylate, polyether-modified siloxane, and ammonia in the base solution is controlled to be 1:0.01-0.10:0.001-0.01; Preferably, the mass ratio of ammonium polycarboxylate to polyether-modified siloxane added to the base solution is 1:0.1-0.

5.

7. The preparation method according to claim 4, characterized in that, The feeding method includes: adding the TiCl4 solution dropwise to the bottom liquid in the reactor, maintaining the temperature in the reactor between 15-35℃, and stirring thoroughly for 30 minutes after feeding is completed; Preferably, the dropping rate of the TiCl4 solution is controlled at 20-33 L / min.

8. The preparation method according to claim 4, characterized in that, The aging and crystal growth process includes: after the material is fed, the reactor is turned on for cold circulation, the temperature is stabilized at 5-25℃, the stirring is turned off and the reactor is left to stand for 1 hour to allow the crystals to precipitate uniformly.

9. The preparation method according to claim 4, characterized in that, Post-processing includes: sequentially performing solid-liquid coarse separation, purification, and drying on the aged crystal-grown slurry; Preferably, the post-processing includes the following steps: draining the supernatant of the slurry after aging and crystal growth, diluting the remaining concentrate in the reactor with pure water, concentrating and purifying it using a ceramic membrane while adding pure water until the conductivity reaches below 50 μS / cm, and then spray drying to obtain ultrafine highly dispersed nano-TiO2.

10. The application of the ultrafine highly dispersed nano-TiO2 according to any one of claims 1-2 or the ultrafine highly dispersed nano-TiO2 prepared by the preparation method according to any one of claims 3-9 in the fields of dielectrics, electron transport, photocatalysis, cosmetics and new energy batteries.

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