CN111573724A - Method for preparing nano titanium dioxide - Google Patents

Method for preparing nano titanium dioxide Download PDF

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Publication number
CN111573724A
CN111573724A CN202010362951.9A CN202010362951A CN111573724A CN 111573724 A CN111573724 A CN 111573724A CN 202010362951 A CN202010362951 A CN 202010362951A CN 111573724 A CN111573724 A CN 111573724A
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titanium dioxide
slurry
nano titanium
metatitanic acid
sulfate
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Inventor
覃愿
黎华挺
许献凤
唐志伟
林汉登
唐月坤
梁娜
祝丽萍
唐艳萍
黎永秀
黄保忠
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Guangxi Jinmao Titanium Co ltd
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Guangxi Jinmao Titanium Co ltd
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    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G23/00—Compounds of titanium
    • C01G23/04—Oxides; Hydroxides
    • C01G23/047—Titanium dioxide
    • C01G23/053—Producing by wet processes, e.g. hydrolysing titanium salts
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    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
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    • B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
    • B01D53/86—Catalytic processes
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    • B01J21/00—Catalysts comprising the elements, oxides, or hydroxides of magnesium, boron, aluminium, carbon, silicon, titanium, zirconium, or hafnium
    • B01J21/06—Silicon, titanium, zirconium or hafnium; Oxides or hydroxides thereof
    • B01J21/063—Titanium; Oxides or hydroxides thereof
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    • C09C1/00—Treatment of specific inorganic materials other than fibrous fillers; Preparation of carbon black
    • C09C1/36—Compounds of titanium
    • C09C1/3607—Titanium dioxide
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    • C09C1/00—Treatment of specific inorganic materials other than fibrous fillers; Preparation of carbon black
    • C09C1/36—Compounds of titanium
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    • C09C1/3615—Physical treatment, e.g. grinding, treatment with ultrasonic vibrations
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    • C09C1/00—Treatment of specific inorganic materials other than fibrous fillers; Preparation of carbon black
    • C09C1/36—Compounds of titanium
    • C09C1/3607—Titanium dioxide
    • C09C1/3615—Physical treatment, e.g. grinding, treatment with ultrasonic vibrations
    • C09C1/363—Drying, calcination
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    • C09C1/00—Treatment of specific inorganic materials other than fibrous fillers; Preparation of carbon black
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    • C09C3/00—Treatment in general of inorganic materials, other than fibrous fillers, to enhance their pigmenting or filling properties
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    • C09C3/00—Treatment in general of inorganic materials, other than fibrous fillers, to enhance their pigmenting or filling properties
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    • C09C3/00—Treatment in general of inorganic materials, other than fibrous fillers, to enhance their pigmenting or filling properties
    • C09C3/04—Physical treatment, e.g. grinding, treatment with ultrasonic vibrations
    • C09C3/043—Drying, calcination
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
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    • B01D2258/0283—Flue gases
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    • C01P2006/22—Rheological behaviour as dispersion, e.g. viscosity, sedimentation stability

Abstract

The invention discloses a method for preparing nano titanium dioxide, which comprises the steps of washing metatitanic acid prepared by a sulfuric acid method, performing filter pressing by a filter press, and adding water to adjust the metatitanic acid to obtain metatitanic acid slurry with titanium dioxide concentration of 150-; adding sulfate, urea and ammonium dihydrogen phosphate into metatitanic acid slurry, heating to 60-80 deg.C, stirring, standing for 2-4 hr, and neutralizing with ammonia water to pH of 6.5-7.5 to obtain hydrolyzed slurry; heating the hydrolyzed slurry to 80-100 ℃, adding concentrated hydrochloric acid with the volume ratio of 0.5-1:1 to the hydrolyzed slurry, pressurizing to perform sol reaction, and adding ammonia water to neutralize the reaction product until the pH value is 6-7 to obtain nano titanium dioxide slurry; and adding a dispersing agent into the nano titanium dioxide slurry, carrying out filter pressing by a filter press, carrying out flash evaporation drying on a pressed filter cake, and crushing by using a steam flow crusher to obtain the nano titanium dioxide. The titanium dioxide prepared by the method has the particle size distribution of 20-30nm, the specific surface area of 370-420cm2/g, the water dispersibility of more than 98 percent, and the titanium dioxide has good catalytic effect when being applied to flue gas denitration.

Description

Method for preparing nano titanium dioxide
Technical Field
The invention belongs to the technical field of titanium dioxide production, and particularly relates to a method for preparing nano titanium dioxide.
Background
Titanium dioxide, i.e. titanium dioxide, is an important inorganic chemical raw material. Because of its non-toxicity, stable physical and chemical properties, it has excellent optical and electrical properties and excellent pigment performance, and can be extensively used in the fields of coating, printing ink, plastics, rubber, paper-making, chemical fibre, art pigment, daily cosmetics, enamel, ceramics and electronics, etc. The production method of titanium dioxide is mainly sulfuric acid process, and is characterized by that the titanium iron powder and concentrated sulfuric acid are undergone the process of acidolysis reaction to produce intermediate titanyl sulfate, the titanyl sulfate must be hydrolyzed into metatitanic acid and sulfuric acid, and the metatitanic acid is undergone the processes of water-washing, calcining and pulverizing so as to obtain the titanium dioxide product.
The flue gas denitration catalytic reaction is a surface reaction, and the reaction speed depends on the contact degree of the reactants and the contact surface of the catalyst. The photocatalytic capacity of titanium dioxide is mainly determined by the surface area, and for the catalyst titanium dioxide, the larger the specific surface area is, the TiO is2The higher the content of the titanium pigment, the lower the impurity content, and the better the catalytic effect, which is the most important index for measuring the quality of the titanium pigment. The specific surface area of the titanium dioxide prepared by the conventional sulfuric acid method is more than 60-100 m2The catalyst has the defects of high production cost, poor catalytic effect, short service life and the like. The nanometer titanium dioxide has smaller granularity and poorer dispersibility and is easy to agglomerate. Therefore, an effective way for improving the flue gas denitration catalysis effect when titanium dioxide with large specific surface area, small granularity and good dispersibility is researched.
Disclosure of Invention
The invention provides a method for preparing nano titanium dioxide, aiming at solving the problems of small specific surface area, easy agglomeration and the like of the existing titanium dioxide. The nano titanium dioxide prepared by the method has the advantages of large specific surface area, nano-grade particle size, good dispersibility and the like, and has good catalytic effect when being applied to flue gas denitration.
In order to achieve the above purpose, the technical scheme adopted by the invention is as follows:
a method for preparing nano titanium dioxide comprises the following steps:
(1) washing metatitanic acid prepared by a sulfuric acid method with water, performing filter pressing by a filter press, and adding water to adjust the metatitanic acid to obtain metatitanic acid slurry with the titanium dioxide concentration of 150-250 g/L;
(2) adding sulfate, urea and ammonium dihydrogen phosphate into metatitanic acid slurry, heating to 60-80 deg.C, stirring, standing for 2-4 hr, and neutralizing with ammonia water to pH of 6.5-7.5 to obtain hydrolyzed slurry; the addition amounts of the sulfate, the urea and the ammonium dihydrogen phosphate are respectively 1-3%, 0.5-1.5% and 0.5-1.5% based on the titanium dioxide in the metatitanic acid slurry;
(3) heating the hydrolyzed slurry to 80-100 ℃, adding concentrated hydrochloric acid with the volume ratio of 0.5-1:1 to the hydrolyzed slurry, pressurizing to perform sol reaction, and adding ammonia water to neutralize the reaction product until the pH value is 6-7 to obtain nano titanium dioxide slurry;
(4) and adding a dispersing agent into the nano titanium dioxide slurry, carrying out filter pressing by a filter press, carrying out flash evaporation drying on a pressed filter cake, and crushing by using a steam flow crusher to obtain the nano titanium dioxide.
Further, the dispersant is composed of cocamidopropyl betaine, polyglycerin fatty acid ester and polyethylene glycol. Preferably, the dispersant is added in an amount of 0.5 to 2.0% by weight based on the weight of titanium dioxide in the slurry. Preferably, the mass ratio of the cocamidopropyl betaine, the polyglycerol fatty acid ester and the polyethylene glycol in the dispersing agent is 1-3:1-3: 3-5.
Further, the sol reaction is carried out for 1-3h at the temperature of 100-120 ℃ and the pressure of 0.4-0.6 MPa.
Further, the filter pressing in the step (1) and the step (4) is carried out until the solid content is 50-60%.
Further, the flash drying temperature is controlled at 400-500 ℃.
Further, the sulfate is one or more of sodium sulfate, potassium sulfate, aluminum potassium sulfate and aluminum sulfate.
Compared with the prior art, the invention has the advantages and beneficial effects that:
1. the titanium dioxide prepared by the method has the particle size distribution of 20-30nm and the specific surface area of 370-420cm2The water dispersibility is up to more than 98%, and the catalyst has a good catalytic effect when being applied to flue gas denitration.
2. According to the method, sulfate, urea and ammonium dihydrogen phosphate are added into metatitanic acid slurry, and sol reaction is performed, so that the titanium dioxide can be controlled to reach a nanometer level, the particle size distribution of the prepared product is narrow, the aperture of the titanium dioxide can be enlarged, and the specific surface area is increased.
3. The method of the invention adds the dispersing agent consisting of the cocamidopropyl betaine, the polyglycerol fatty acid ester and the polyethylene glycol, can obviously improve the dispersibility of the titanium dioxide, and solves the problem of low catalytic efficiency caused by easy agglomeration of the existing titanium dioxide.
Detailed Description
The present invention will be described in further detail with reference to specific embodiments. It should be emphasized that the following description is merely exemplary in nature and is not intended to limit the scope of the invention or its application.
Example 1
A method for preparing nano titanium dioxide comprises the following steps:
(1) washing metatitanic acid prepared by a sulfuric acid method with water, performing filter pressing by a filter press, and adding water to adjust the metatitanic acid to obtain metatitanic acid slurry with the titanium dioxide concentration of 200 g/L;
(2) adding aluminum potassium sulfate, urea and ammonium dihydrogen phosphate into metatitanic acid slurry, heating to 70 ℃, uniformly stirring, standing for 3h, and neutralizing with ammonia water until the pH value is 7.0 to obtain hydrolysis slurry; the addition amounts of the sulfate, the urea and the ammonium dihydrogen phosphate are respectively 2%, 1.2% and 0.8% based on titanium dioxide in the metatitanic acid slurry;
(3) heating the hydrolyzed slurry to 90 ℃, adding concentrated hydrochloric acid with the volume ratio of 1:2 to the hydrolyzed slurry, pressurizing to perform sol reaction, reacting for 2.5 hours at the temperature of 110 ℃ and the pressure of 0.5MPa, and adding ammonia water to neutralize until the pH value is 6.5 after the reaction is finished to obtain nano titanium dioxide slurry;
(4) adding a dispersing agent with the addition amount of 1.2 percent based on the weight of titanium dioxide in the slurry into the nano titanium dioxide slurry, wherein the dispersing agent consists of coconut oil amide propyl betaine, polyglycerol fatty acid ester and polyethylene glycol with the mass ratio of 2:1:3, performing pressure filtration by a filter press until the solid content is 55 percent, performing flash evaporation drying on a filter cake after the pressing at the temperature of 450 ℃, and crushing by using a steam flow crusher to obtain the nano titanium dioxide.
Example 2
A method for preparing nano titanium dioxide comprises the following steps:
(1) washing metatitanic acid prepared by a sulfuric acid method with water, performing filter pressing by a filter press, and adding water to adjust the metatitanic acid to obtain metatitanic acid slurry with titanium dioxide concentration of 150 g/L;
(2) adding aluminum sulfate, urea and ammonium dihydrogen phosphate into metatitanic acid slurry, heating to 65 ℃, uniformly stirring, standing for 2 hours, and neutralizing with ammonia water until the pH value is 6.5 to obtain hydrolysis slurry; the addition amounts of the sulfate, the urea and the ammonium dihydrogen phosphate are respectively 1.5%, 0.8% and 1.2% based on titanium dioxide in the metatitanic acid slurry;
(3) heating the hydrolyzed slurry to 100 ℃, adding concentrated hydrochloric acid with the volume ratio of 1:1 to the hydrolyzed slurry, pressurizing to perform sol reaction, reacting for 2 hours at the temperature of 120 ℃ and the pressure of 0.4MPa, and adding ammonia water to neutralize until the pH value is 6.5 after the reaction is finished to obtain nano titanium dioxide slurry;
(4) the nano titanium dioxide slurry is added with a dispersant accounting for 1.8 percent of the weight of titanium dioxide in the slurry, and the dispersant consists of cocamidopropyl betaine, polyglycerol fatty acid ester and polyethylene glycol in a mass ratio of 1:1: 4. Filter-pressing the mixture by a filter press until the solid content is 60 percent, flash-evaporating and drying the pressed filter cake at the temperature of 500 ℃, and crushing the filter cake by a steam flow crusher to obtain the nano titanium dioxide.
Example 3
A method for preparing nano titanium dioxide comprises the following steps:
(1) washing metatitanic acid prepared by a sulfuric acid method with water, performing filter pressing by a filter press, and adding water to adjust the metatitanic acid to obtain metatitanic acid slurry with the titanium dioxide concentration of 250 g/L;
(2) adding sodium sulfate, urea and ammonium dihydrogen phosphate into metatitanic acid slurry, heating to 80 ℃, uniformly stirring, standing for 3h, and neutralizing with ammonia water until the pH value is 7.0 to obtain hydrolysis slurry; the addition amounts of the sulfate, the urea and the ammonium dihydrogen phosphate are respectively 2%, 1% and 0.8% based on titanium dioxide in the metatitanic acid slurry;
(3) heating the hydrolyzed slurry to 90 ℃, adding concentrated hydrochloric acid with the volume ratio of 1:1 to the hydrolyzed slurry, pressurizing to perform sol reaction, reacting for 2.5 hours at the temperature of 110 ℃ and the pressure of 0.5MPa, and adding ammonia water to neutralize until the pH value is 6.5 after the reaction is finished to obtain nano titanium dioxide slurry;
(4) adding 0.8% of dispersing agent by weight of titanium dioxide in the slurry into the nano titanium dioxide slurry, wherein the dispersing agent consists of cocamidopropyl betaine, polyglycerol fatty acid ester and polyethylene glycol in a mass ratio of 3:2:5, performing pressure filtration by a filter press until the solid content is 55%, performing flash evaporation drying on a filter cake after the pressing at the temperature of 400 ℃, and crushing by a steam flow crusher to obtain the nano titanium dioxide.
Example 4
A method for preparing nano titanium dioxide comprises the following steps:
(1) washing metatitanic acid prepared by a sulfuric acid method with water, performing filter pressing by a filter press, and adding water to adjust the metatitanic acid to obtain metatitanic acid slurry with the titanium dioxide concentration of 200 g/L;
(2) adding potassium sulfate, urea and ammonium dihydrogen phosphate into metatitanic acid slurry, heating to 70 ℃, uniformly stirring, standing for 4h, and neutralizing with ammonia water until the pH value is 6.5 to obtain hydrolysis slurry; the addition amounts of the sodium sulfate, the urea and the ammonium dihydrogen phosphate are respectively 3%, 0.6% and 1.2% based on titanium dioxide in the metatitanic acid slurry;
(3) heating the hydrolyzed slurry to 100 ℃, adding concentrated hydrochloric acid with the volume ratio of 1:1.5 to the hydrolyzed slurry, pressurizing to perform sol reaction, reacting for 3 hours at the temperature of 100 ℃ and the pressure of 0.6MPa, and adding ammonia water to neutralize until the pH value is 7.0 after the reaction is finished to obtain nano titanium dioxide slurry;
(4) the nano titanium dioxide slurry is added with a dispersant accounting for 1.5 percent of the weight of titanium dioxide in the slurry, and the dispersant consists of coconut oil amide propyl betaine, polyglycerol fatty acid ester and polyethylene glycol in a mass ratio of 1:1: 3. Filter-pressing by a filter press until the solid content is 50%, flash-drying the pressed filter cake at the temperature of 450 ℃, and crushing by a steam flow crusher to obtain the nano titanium dioxide.
Example 5
A method for preparing nano titanium dioxide comprises the following steps:
(1) washing metatitanic acid prepared by a sulfuric acid method with water, performing filter pressing by a filter press, and adding water to adjust the metatitanic acid to obtain metatitanic acid slurry with the titanium dioxide concentration of 250 g/L;
(2) adding aluminum potassium sulfate, urea and ammonium dihydrogen phosphate into metatitanic acid slurry, heating to 80 ℃, uniformly stirring, standing for 3h, and neutralizing with ammonia water until the pH value is 7.5 to obtain hydrolysis slurry; the addition amounts of the sodium sulfate, the urea and the ammonium dihydrogen phosphate are respectively 1.5%, 1% and 1% based on titanium dioxide in the metatitanic acid slurry;
(3) heating the hydrolyzed slurry to 120 ℃, adding concentrated hydrochloric acid with the volume ratio of 1:1 to the hydrolyzed slurry, pressurizing to perform sol reaction, reacting for 2 hours at the temperature of 120 ℃ and the pressure of 0.5MPa, and adding ammonia water to neutralize until the pH value is 7.0 after the reaction is finished to obtain nano titanium dioxide slurry;
(4) the nano titanium dioxide slurry is added with a dispersant accounting for 2% of the weight of titanium dioxide in the slurry, and the dispersant consists of cocamidopropyl betaine, polyglycerol fatty acid ester and polyethylene glycol in a mass ratio of 2:3: 3. Filter-pressing the mixture by a filter press until the solid content is 60 percent, flash-evaporating and drying the pressed filter cake at the temperature of 400 ℃, and crushing the filter cake by a steam flow crusher to obtain the nano titanium dioxide.
The titanium dioxide prepared in the examples 1 to 5 is tested for specific surface area, particle size and dispersibility by a conventional method, and the test results are shown in table 1.
Table 1: performance detection result of nano titanium dioxide prepared by the invention
Product(s) Specific surface area (cm)2/g) Average particle diameter (nm) Water dispersibility (%)
Example 1 397 25.6 98.46
Example 2 416 23.4 99.03
Example 3 371 27.1 98.11
Example 4 385 21.2 98.97
Example 5 409 27.4 99.14
The nano titanium dioxide prepared by the method has the advantages of large specific surface area, nano-grade particle size, good dispersibility and the like.
The titanium dioxide prepared in the embodiments 1-5 of the invention is applied to flue gas denitration, and the titanium dioxide has 950ppm NOx and 3.2% O in the flue gas condition2、165ppm SO2The reaction was carried out at a gas flow rate of 300ml/min and a temperature of 450 ℃. The denitration rates of examples 1 to 5 were: 98.64%, 99.17%, 98.26%, 98.18% and 98.74%.
The foregoing is a more detailed description of the invention in connection with specific/preferred embodiments and is not intended to limit the practice of the invention to those descriptions. It will be apparent to those skilled in the art that various substitutions and modifications can be made to the described embodiments without departing from the spirit of the invention, and such substitutions and modifications are to be considered as within the scope of the invention.

Claims (8)

1. A method for preparing nano titanium dioxide is characterized by comprising the following steps: the method comprises the following steps:
(1) washing metatitanic acid prepared by a sulfuric acid method with water, performing filter pressing by a filter press, and adding water to adjust the metatitanic acid to obtain metatitanic acid slurry with the titanium dioxide concentration of 150-250 g/L;
(2) adding sulfate, urea and ammonium dihydrogen phosphate into metatitanic acid slurry, heating to 60-80 deg.C, stirring, standing for 2-4 hr, and neutralizing with ammonia water to pH of 6.5-7.5 to obtain hydrolyzed slurry; the addition amounts of the sulfate, the urea and the ammonium dihydrogen phosphate are respectively 1-3%, 0.5-1.5% and 0.5-1.5% based on the titanium dioxide in the metatitanic acid slurry;
(3) heating the hydrolyzed slurry to 80-100 ℃, adding concentrated hydrochloric acid with the volume ratio of 0.5-1:1 to the hydrolyzed slurry, pressurizing to perform sol reaction, and adding ammonia water to neutralize the reaction product until the pH value is 6-7 to obtain nano titanium dioxide slurry;
(4) and adding a dispersing agent into the nano titanium dioxide slurry, carrying out filter pressing by a filter press, carrying out flash evaporation drying on a pressed filter cake, and crushing by using a steam flow crusher to obtain the nano titanium dioxide.
2. The method for preparing nano titanium dioxide according to claim 1, which is characterized in that: the dispersing agent consists of cocamidopropyl betaine, polyglycerol fatty acid ester and polyethylene glycol.
3. The method for preparing nano titanium dioxide according to claim 2, characterized in that: the dispersant is added in an amount of 0.5-2.0% by weight of the titanium dioxide in the slurry.
4. The method for preparing nano titanium dioxide according to claim 2, characterized in that: the mass ratio of the cocamidopropyl betaine, the polyglycerol fatty acid ester and the polyethylene glycol in the dispersing agent is 1-3:1-3: 3-5.
5. The method of nano titanium dioxide according to claim 1, characterized in that: the sol reaction is carried out for 1-3h at the temperature of 100-120 ℃ and the pressure of 0.4-0.6 MPa.
6. The method for preparing nano titanium dioxide according to claim 1, which is characterized in that: and (3) performing pressure filtration in the step (1) and the step (4) until the solid content is 50-60%.
7. The method for preparing nano titanium dioxide according to claim 1, which is characterized in that: the flash drying temperature is controlled at 400-500 ℃.
8. The method for preparing nano titanium dioxide according to claim 1, which is characterized in that: the sulfate is one or a combination of sodium sulfate, potassium sulfate, aluminum potassium sulfate and aluminum sulfate.
CN202010362951.9A 2020-04-30 2020-04-30 Method for preparing nano titanium dioxide Pending CN111573724A (en)

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Citations (6)

* Cited by examiner, † Cited by third party
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US5840111A (en) * 1995-11-20 1998-11-24 Bayer Ag Nanodisperse titanium dioxide, process for the production thereof and use thereof
CN101029187A (en) * 2006-03-03 2007-09-05 攀钢集团攀枝花钢铁研究院 High-dispersed titanium pigment and its production
CN104477984A (en) * 2014-11-21 2015-04-01 广西美之峰科技有限责任公司 Preparation method of nano titanium dioxide serving as flue gas denitrification catalyst
CN106379936A (en) * 2016-08-31 2017-02-08 南京钛白化工有限责任公司 Preparation method of high specific surface area titanium dioxide for denitration catalyst
CN108516582A (en) * 2018-04-28 2018-09-11 南京钛白化工有限责任公司 A kind of preparation method of high durable nano rutile-type titanium dioxide
CN110510668A (en) * 2018-10-31 2019-11-29 西安电子科技大学 Adsorb the anatase titanium dioxide preparation method of heavy metal chromium

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5840111A (en) * 1995-11-20 1998-11-24 Bayer Ag Nanodisperse titanium dioxide, process for the production thereof and use thereof
CN101029187A (en) * 2006-03-03 2007-09-05 攀钢集团攀枝花钢铁研究院 High-dispersed titanium pigment and its production
CN104477984A (en) * 2014-11-21 2015-04-01 广西美之峰科技有限责任公司 Preparation method of nano titanium dioxide serving as flue gas denitrification catalyst
CN106379936A (en) * 2016-08-31 2017-02-08 南京钛白化工有限责任公司 Preparation method of high specific surface area titanium dioxide for denitration catalyst
CN108516582A (en) * 2018-04-28 2018-09-11 南京钛白化工有限责任公司 A kind of preparation method of high durable nano rutile-type titanium dioxide
CN110510668A (en) * 2018-10-31 2019-11-29 西安电子科技大学 Adsorb the anatase titanium dioxide preparation method of heavy metal chromium

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Application publication date: 20200825