阅读说明：本技术 一种气相法纳米二氧化钛的制备工艺 (Preparation process of nano titanium dioxide by gas phase method ) 是由 石进 胡晞 颜卫卫 刘国栋 施宸 于 2020-07-06 设计创作，主要内容包括：本发明涉及纳米材料制备技术领域,具体涉及一种气相法纳米二氧化硅的制备工艺。本发明的第一个方面提供了一种气相法纳米二氧化钛的制备工艺,包括以下步骤：(1)将钛粒加入装置中,升温至200℃以上；(2)将氯气从装置底部通入,与钛粒接触反应后,生成四氯化钛蒸汽；(3)将四氯化钛蒸汽与惰性气体混合后,经喷嘴喷入水蒸气混合气中,反应生成氧化钛；(4)气固分离,即得二氧化钛。本发明提供的制备工艺,原料易得、反应速度快、工艺流程短,能够实现连续化生产,且制备得到的纳米二氧化钛具有纯度高、分散性好、团聚少、比表活性大等优点。(The invention relates to the technical field of nano material preparation, in particular to a preparation process of nano silicon dioxide by a vapor phase method. The invention provides a preparation process of nano titanium dioxide by a vapor phase method, which comprises the following steps: (1) adding titanium particles into a device, and heating to more than 200 ℃; (2) introducing chlorine from the bottom of the device, and generating titanium tetrachloride vapor after the chlorine is in contact reaction with titanium particles; (3) mixing titanium tetrachloride steam with inert gas, spraying the mixture into the steam mixed gas through a nozzle, and reacting to generate titanium oxide; (4) gas-solid separation to obtain the titanium dioxide. The preparation process provided by the invention has the advantages of easily available raw materials, high reaction speed, short process flow and capability of realizing continuous production, and the prepared nano titanium dioxide has the advantages of high purity, good dispersibility, less agglomeration, high specific surface activity and the like.)

1. A preparation process of vapor phase nano titanium dioxide is characterized by comprising the following steps:

(1) adding titanium particles into a device, and heating to more than 200 ℃;

(2) introducing chlorine from the bottom of the device, and generating titanium tetrachloride vapor after the chlorine is in contact reaction with titanium particles;

(3) Mixing titanium tetrachloride steam with inert gas, spraying the mixture into the steam mixed gas through a nozzle, and reacting to generate titanium oxide;

(4) gas-solid separation to obtain the nanometer titanium dioxide.

2. The process for preparing nano titanium dioxide by a vapor phase method according to claim 1, wherein in the step (1), after the titanium particles are added into the device, the air in the device is replaced by inert gas.

3. The process for preparing nano titanium dioxide by a gas phase method according to claim 1, wherein the chlorine gas in the step (2) is dry chlorine gas.

4. The process for preparing nano titanium dioxide by a gas phase method according to claim 1, wherein the temperature of the inert gas in the step (3) is not lower than 200 ℃.

5. The process for preparing nano titanium dioxide by a vapor phase method according to claim 1, wherein the mixed gas of water vapor in the step (3) is a mixture of water vapor and oxidizing gas.

6. The process for preparing nano titanium dioxide by a vapor phase method according to claim 5, wherein the oxidizing gas comprises at least oxygen.

7. The process for preparing nano titanium dioxide by a vapor phase method according to claim 5, wherein the temperature of the water vapor mixed gas is not lower than 600 ℃.

8. The process for preparing nano titanium dioxide by vapor phase process according to claim 1, wherein in the step (3), the volume ratio of the titanium tetrachloride vapor, the inert gas and the water vapor mixed gas is 1: (0.1-0.5): (1.5-5).

9. The process for preparing nano titanium dioxide by a vapor phase method according to claim 1, wherein in the step (3), the gas flow velocity sprayed through the nozzle is not less than 50 m/s.

10. Nano titanium dioxide particles, characterized in that they are obtained by a process for the preparation of nano titanium dioxide according to the vapor phase process of any one of claims 1 to 9.

Technical Field

The invention relates to the technical field of nano material preparation, in particular to a preparation process of nano silicon dioxide by a vapor phase method.

Background

Nano TiO 2₂As a semiconductor catalytic material, the material has stable chemical property, excellent photoelectric property and high-efficiency photocatalytic activity The characteristics, mild reaction conditions and low cost become a research hotspot. Nano TiO 2₂The catalyst can absorb and decompose toxic and harmful gases in the air as an environment-friendly catalyst, thereby achieving the purpose of air purification; nano TiO 2₂The photocatalyst has good bacteriostatic effect on escherichia coli, staphylococcus aureus and salmonella; nano TiO 2₂The crystal can catalyze and decompose water molecules into hydrogen and oxygen molecules, thereby opening up a new field for green and effective utilization of solar energy; nano TiO based on dye adsorption photosensitizer₂The film can be used for a photoelectric solar cell and shows good application prospect; nano TiO 2₂The crystal has the characteristic of high hydrophilicity, and can be used for surface antifogging and self-cleaning of glass, lenses, natural/chemical fibers and the like; nano TiO 2₂Can be used for treating industrial sewage and domestic sewage, and the photocatalyst can rapidly decompose organic pollutants into H₂O and C_O2And the like, so as to achieve the purpose of purifying sewage. Due to the nanometer TiO₂Has wide application prospect in the aspects of catalysis, environmental protection and the like, and can be used in the industrial departments of daily products, coatings, electronics, electric power and the like, therefore, the nano TiO has wide application prospect₂Shows great market prospect.

The preparation method of the nano titanium dioxide can be divided into two major types, namely a liquid phase method and a gas phase method, wherein the liquid phase method is to prepare a titanium dioxide precursor by using titanium salt, and the titanium dioxide precursor is collected, washed and then subjected to heat treatment to obtain a nano titanium dioxide product. The liquid phase method can be classified into a hydrolysis method, a sol-gel method, a micro-emulsion method, an electrochemical method, a hydrothermal synthesis method, and the like. The liquid phase method for preparing the nano titanium dioxide has the advantages of wide raw material source, lower cost, simple equipment and partial method is convenient for large-scale production; however, the liquid phase method easily causes the local concentration of the material to be too high, the particle size and the shape to be uneven, the agglomeration and sintering among particles are easily caused in the drying and calcining processes, the dispersibility of the product is poor, and the use effect and the application range of the product are influenced. The method for preparing nanoparticles by gas phase method is to form primary particles by chemical reaction in gas phase, and then to form final particles by particle growth. The preparation of the nano titanium dioxide by the gas phase method can be divided into a gas phase high-temperature oxidation method and a high-temperature pyrolysis method according to specific methods, and the nano titanium dioxide particles prepared by the gas phase method have the advantages of high activity, good dispersibility, high process continuity degree, and the main defects of single raw material source, high cost, high energy consumption, complex equipment, higher requirement on materials and difficult process control. At present, the domestic nano titanium dioxide industrialized products only adopt a liquid phase method, and the nano titanium dioxide products prepared by a gas phase method all depend on import.

Therefore, the invention provides a preparation process of vapor phase nano titanium dioxide, which has the advantages of easily obtained raw materials, high reaction speed, short process flow and capability of realizing continuous production, and the prepared nano titanium dioxide has the advantages of high purity, good dispersibility, less agglomeration, large specific surface activity and the like.

Disclosure of Invention

In order to solve the technical problems, the first aspect of the invention provides a preparation process of nano titanium dioxide by a vapor phase method, which comprises the following steps:

(1) adding titanium particles into a device, and heating to more than 200 ℃;

(2) introducing chlorine from the bottom of the device, and generating titanium tetrachloride vapor after the chlorine is in contact reaction with titanium particles;

(3) mixing titanium tetrachloride steam with inert gas, spraying the mixture into the steam mixed gas through a nozzle, and reacting to generate titanium oxide;

(4) gas-solid separation to obtain the nanometer titanium dioxide.

In a preferred embodiment of the present invention, in the step (1), after the titanium particles are charged into the apparatus, the air in the apparatus is replaced with an inert gas.

In a preferred embodiment of the present invention, the chlorine gas in the step (2) is dry chlorine gas.

As a preferable technical scheme of the invention, the temperature of the inert gas in the step (3) is not lower than 200 ℃.

In a preferred embodiment of the present invention, the steam-mixed gas in the step (3) is a mixture of steam and an oxidizing gas.

In a preferred embodiment of the present invention, the oxidizing gas includes at least oxygen.

As a preferable technical scheme of the invention, the temperature of the steam mixed gas is not lower than 600 ℃.

In a preferred embodiment of the present invention, in the step (3), a volume ratio of the titanium tetrachloride vapor to the mixed gas of inert gas and water vapor is 1: (0.1-0.5): (1.5-5).

In a preferred embodiment of the present invention, in the step (3), the speed of the air flow ejected through the nozzle is not less than 50 m/s.

The second aspect of the invention provides a nano titanium dioxide particle, which is prepared according to the preparation process of the gas phase method nano titanium dioxide.

Advantageous effects

The invention provides a preparation process of nano titanium dioxide by a vapor phase method, which has the advantages of easily obtained raw materials, high reaction speed, short process flow and capability of realizing continuous production, and the prepared nano titanium dioxide has the advantages of high purity, good dispersibility, less agglomeration, large specific surface activity and the like.

Drawings

FIG. 1 is a scanning electron microscope image of the nano-titanium dioxide prepared in example 1 after ultrasonic dispersion for 5 minutes.

Detailed Description

The disclosure may be understood more readily by reference to the following detailed description of preferred embodiments of the invention and the examples included therein. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In case of conflict, the present specification, including definitions, will control.

The term "prepared from …" as used herein is synonymous with "comprising". The terms "comprises," "comprising," "includes," "including," "has," "having," "contains," "containing," or any other variation thereof, as used herein, are intended to cover a non-exclusive inclusion. For example, a composition, process, method, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, process, method, article, or apparatus.

The conjunction "consisting of …" excludes any unspecified elements, steps or components. If used in a claim, the phrase is intended to claim as closed, meaning that it does not contain materials other than those described, except for the conventional impurities associated therewith. When the phrase "consisting of …" appears in a clause of the subject matter of the claims rather than immediately after the subject matter, it defines only the elements described in the clause; other elements are not excluded from the claims as a whole.

When an amount, concentration, or other value or parameter is expressed as a range, preferred range, or as a range of upper preferable values and lower preferable values, this is to be understood as specifically disclosing all ranges formed from any pair of any upper range limit or preferred value and any lower range limit or preferred value, regardless of whether ranges are separately disclosed. For example, when a range of "1 to 5" is disclosed, the described range should be interpreted to include the ranges "1 to 4", "1 to 3", "1 to 2 and 4 to 5", "1 to 3 and 5", and the like. When a range of values is described herein, unless otherwise stated, the range is intended to include the endpoints thereof and all integers and fractions within the range.

The singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise. "optional" or "any" means that the subsequently described event or events may or may not occur, and that the description includes instances where the event occurs and instances where it does not.

Approximating language, as used herein throughout the specification and claims, is intended to modify a quantity, such that the invention is not limited to the specific quantity, but includes portions that are literally received for modification without substantial change in the basic function to which the invention is related. Accordingly, the use of "about" to modify a numerical value means that the invention is not limited to the precise value. In some instances, the approximating language may correspond to the precision of an instrument for measuring the value. In the present description and claims, range limitations may be combined and/or interchanged, including all sub-ranges contained therein if not otherwise stated.

In addition, the indefinite articles "a" and "an" preceding an element or component of the invention are not intended to limit the number requirement (i.e., the number of occurrences) of the element or component. Thus, "a" or "an" should be read to include one or at least one, and the singular form of an element or component also includes the plural unless the stated number clearly indicates that the singular form is intended.

In order to solve the technical problems, the first aspect of the invention provides a preparation process of nano titanium dioxide by a vapor phase method, which comprises the following steps:

(1) adding titanium particles into a device, and heating to more than 200 ℃;

(2) introducing chlorine from the bottom of the device, and generating titanium tetrachloride vapor after the chlorine is in contact reaction with titanium particles;

(3) mixing titanium tetrachloride steam with inert gas, spraying the mixture into the steam mixed gas through a nozzle, and reacting to generate titanium oxide;

(4) gas-solid separation to obtain the nanometer titanium dioxide.

Step (1)

In the invention, the step (1) is as follows: adding titanium particles into the device, and heating to over 200 ℃.

In a preferred embodiment, the titanium particles are not particularly limited.

In a more preferred embodiment, the titanium particles are titanium sponge and/or titanium powder.

In the present invention, the sources of the titanium sponge and the titanium powder are not particularly limited, and commercially available titanium sponge and titanium powder are suitable for use in the present invention.

In a preferred embodiment, after the titanium pellets are charged into the apparatus, the air in the apparatus is replaced with an inert gas.

In a more preferred embodiment, the inert gas, without particular limitation, may be mentioned nitrogen, helium, neon, argon, and the like.

Step (2)

In the invention, the step (2) is as follows: chlorine is introduced from the bottom of the device and reacts with titanium particles in a contact way to generate titanium tetrachloride vapor.

In a preferred embodiment, the chlorine gas is dry chlorine gas.

Step (3)

In the invention, the step (3) is as follows: titanium tetrachloride vapor and inert gas are mixed and sprayed into the water vapor mixed gas through a nozzle to react to generate titanium oxide.

In a preferred embodiment, the inert gas temperature is not less than 200 ℃.

In a preferred embodiment, the water vapor mixed gas is a mixture of water vapor and an oxidizing gas.

In a more preferred embodiment, the volume ratio of water vapor to oxidizing gas is 1: (0.5-2).

In a most preferred embodiment, the volume ratio of water vapor to oxidizing gas is 1: 1.

In a preferred embodiment, the oxidizing gas comprises at least oxygen.

In a more preferred embodiment, the oxidizing gas is compressed air and/or oxygen.

In a preferred embodiment, the temperature of the steam-gas mixture is not lower than 600 ℃.

In a more preferred embodiment, the temperature of the steam-mixed gas is not lower than 900 ℃.

In a preferred embodiment, the volume ratio of the titanium tetrachloride vapor, the inert gas and the water vapor mixed gas is 1: (0.1-0.5): (1.5-5).

In a more preferred embodiment, the volume ratio of the titanium tetrachloride vapor, the inert gas and the water vapor mixed gas is 1: (0.15-0.3): (2-4).

In a most preferred embodiment, the volume ratio of the titanium tetrachloride vapor, the inert gas and the water vapor mixed gas is 1: 0.2: 3.

in a preferred embodiment, the velocity of the air stream ejected through the nozzle is not less than 50 m/s.

In a more preferred embodiment, the velocity of the gas stream ejected through the nozzle is in the range of 50 to 500 m/s.

In a preferred embodiment, the nozzle has a bore diameter of 1 to 10 mm.

In a most preferred embodiment, the nozzle diameter is 5mm and the gas flow rate is 100m/s, the titanium dioxide produced has an average particle diameter of not more than 20 nm.

The inventor finds that the flow rate of the water vapor mixed gas directly influences the particle size of the titanium dioxide, the aperture of the nozzle is increased, and the gas flow speed is properly reduced; the aperture of the nozzle is reduced, so that the airflow is properly improved; the nozzle aperture and the variation of the air flow velocity are not particularly limited and can be adjusted according to experimental conditions.

Step (4)

In the invention, the step (4) is as follows: gas-solid separation to obtain the titanium dioxide.

In the invention, the gas after the reaction is finished is treated according to an acid gas recovery treatment mode; the acid gas recovery treatment method is not particularly limited.

In the invention, the preparation process of the nano titanium dioxide comprises the following steps:

(1) adding titanium particles into a device, then replacing air in the device with inert gas, and heating to more than 200 ℃;

(2) introducing dry chlorine from the bottom of the device, and generating titanium tetrachloride steam after the dry chlorine is in contact reaction with titanium particles;

(3) heating inert gas to over 200 deg.c; heating the steam mixed gas to over 900 ℃; the steam mixed gas is a mixture of steam and oxygen, and the volume ratio is 1: 1;

(4) mixing titanium tetrachloride steam with the heated inert gas, and spraying the mixture into the steam mixed gas through a nozzle with the aperture of 5mm at the gas flow speed of 100m/s to react to generate titanium oxide; the volume ratio of the titanium tetrachloride vapor to the inert gas to the water vapor mixed gas is 1: 0.2: 3;

(4) Gas-solid separation to obtain the nanometer titanium dioxide.

The present invention will be specifically described below by way of examples. It should be noted that the following examples are only for illustrating the present invention and should not be construed as limiting the scope of the present invention, and that the insubstantial modifications and adaptations of the present invention by those skilled in the art based on the above disclosure are still within the scope of the present invention.

In addition, the starting materials used are all commercially available, unless otherwise specified.