Titanium dioxide / calcium oxide composite material as well as preparation method and application thereof

Abstract

The invention provides a titanium dioxide / calcium oxide composite material as well as a preparation method and application thereof, and relates to the technical field of inorganic materials. Specifically, CaCO3, TiCl4 and O2 which are preheated respectively are mixed, vapor deposition reaction is carried out, and the CaCO3 composite material with the surface coated with TiO2 is obtained. The invention provides a composite material in which a titanium dioxide thin layer is uniformly deposited on the surface of calcium carbonate particles, the cost is effectively reduced on the premise of ensuring the quality of high-level covering power, and the composite material is applied to various fields of pigments, foods, battery materials, photocatalysis and the like. The preparation process is simple, convenient and high in stability, the thickness and the coating amount of the coating layer can be effectively controlled by controlling feeding of the raw materials, and the obtained titanium dioxide / calcium oxide composite material is low in impurity content and stable in quality index.

Description

Technical Field

[0001] The invention relates to the technical field of inorganic materials, and in particular to a titanium dioxide / calcium oxide composite material and a preparation method and application thereof. Background Art

[0002] Calcium carbonate is an important industrial filler, and the filling amount is generally around 5% to 30%. By doping or coating calcium carbonate, the hardness or rigidity of the product, dimensional stability, astigmatism, heat resistance and processing performance of the product can be improved. For example, in the papermaking industry, it has high whiteness and fine particles, which can significantly improve the opacity, ink absorption rate and drying rate of paper, making it an ideal filler that can improve the quality of ink in the papermaking process. For another example, in the rubber industry, as an important filler and reinforcing agent for rubber, calcium carbonate can improve the tear resistance, vulcanization elongation and flexural resistance of the masterbatch. Therefore, calcium carbonate is widely used as an important inorganic filler in coatings, rubber, ink, plastics and papermaking. With the continuous development and progress of these industries, higher requirements are placed on the hiding power of calcium carbonate.

[0003] Titanium dioxide has strong adhesion, is not easy to undergo chemical changes, has excellent opacity, whiteness and brightness, and is considered to be the best white pigment currently available; it has similar properties to calcium carbonate and can also be applied to the technical field of calcium carbonate and achieve better functional effects. Specifically, the refractive index of calcium carbonate particles is 1.58, the refractive index of anatase titanium dioxide particles is 2.55, and the refractive index of rutile titanium dioxide particles is 2.71. It can be seen that the refractive index of titanium dioxide is significantly higher than that of calcium carbonate, so the hiding power is also significantly higher than that of calcium carbonate.

[0004] Titanium dioxide is widely used because of its excellent, irreplaceable hiding power and high whiteness. However, compared with calcium carbonate, titanium dioxide has a high cost and complex process, making it difficult to achieve high-quality and large-scale application.

[0005] In view of this, the present invention is proposed. Summary of the invention

[0006] The first purpose of the present invention is to provide a method for preparing a titanium dioxide / calcium oxide composite material, which is used to solve the current technical problems of insufficient covering power of calcium carbonate and high cost of titanium dioxide. The present invention prepares a titanium dioxide / calcium oxide composite material coated with TiO 2 CaCO 3 The composite material has a simple preparation process, easy operation and stable operation; the prepared composite material has good whiteness (and hiding power) in various fields as an industrial filler, and effectively reduces the total cost of raw materials.

[0007] The second object of the present invention is to provide a titanium dioxide / calcium oxide composite material, wherein the obtained composite material has low impurity content and stable quality indicators.

[0008] The third object of the present invention is to provide an application of the titanium dioxide / calcium oxide composite material as a filler in various industrial fields.

[0009] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are particularly adopted:

[0010] A method for preparing a titanium dioxide / calcium oxide composite material comprises the following steps:

[0011] The preheated CaCO 3 、TiCl 4 and O 2 Mix and perform vapor deposition reaction to obtain a surface coated with TiO 2 CaCO 3 Composite materials.

[0012] A titanium dioxide / calcium oxide composite material is prepared based on the preparation method of the titanium dioxide / calcium oxide composite material, and the use of the titanium dioxide / calcium oxide composite material in pigments, fillers, food, battery materials or photocatalysis.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] The present invention provides a titanium dioxide / calcium oxide composite material and its supporting preparation process flow, specifically a composite material with a titanium dioxide thin layer uniformly deposited on the surface of calcium carbonate particles, which can replace calcium carbonate or titanium dioxide to reduce costs while ensuring hiding power, and can be used in various fields such as pigments, food and battery materials, photocatalysis, etc.

[0015] The present invention can ensure that a simple reaction system can produce a mixing scale that meets the requirements through simple gas-solid phase mixing, thereby achieving the purpose of rapid and uniform mixing, and can obtain calcium carbonate particles uniformly coated with titanium dioxide by matching the ratio of calcium carbonate and titanium tetrachloride, and can control the coating amount of titanium dioxide by controlling the ratio of titanium tetrachloride and oxygen; thereby, an inorganic composite filling material with high refractive index and strong covering power is produced. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 Provides a SEM image of Example 1 of the present invention;

[0018] Figure 2 An element distribution diagram of Example 1 of the present invention is provided, wherein: Figure 2 (a) is the distribution diagram of all elements, Figure 2 (b) is the distribution diagram of calcium element. Figure 2 (c) is the distribution diagram of titanium element;

[0019] Figure 3 The energy spectrum diagram of Example 1 of the present invention is provided. DETAILED DESCRIPTION

[0020] The technical scheme of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and specific embodiments, but those skilled in the art will appreciate that the following described embodiments are part of embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention, and should not be considered as limiting the scope of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention. If specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer is not specified in the reagents or instruments used, they are all conventional products that can be purchased commercially. In addition, the terms "first", "second" and "third" are only used for descriptive purposes and cannot be interpreted as indicating or implying relative importance.

[0021] The first aspect of the present invention is to provide a method for preparing a titanium dioxide / calcium oxide composite material. The preparation method mainly comprises the following steps: preheating the CaCO 3 、TiCl 4 and O 2 Mix and perform vapor deposition reaction to obtain a surface coated with TiO 2 CaCO 3 Composite materials.

[0022] In the present invention, the gaseous TiCl 4 and O 2 In CaCO 3 The surface contacts and reacts rapidly to form TiO 2 and attached to the surface of calcium carbonate; with the TiCl 4 and O 2 TiO 2 Continuously generated, as CaCO 3 The continuous feeding and discharging of the generated TiO 2 Attached to CaCO 3The particles are continuously taken out to ensure that TiO 2 In CaCO 3 Uniformity and stability of particle surface attachment.

[0023] As a preferred embodiment, TiCl 4 The preheating temperature is 100°C to 400°C; in some more preferred embodiments, TiCl 4 The preheating temperature is 140°C to 400°C, including but not limited to any one of 140, 150, 160, 180, 200, 250, 300, 350, 380, 400 (°C) or a numerical range consisting of any two of them.

[0024] As a preferred embodiment, CaCO 3 The preheating temperature is 100°C to 400°C, including but not limited to any one of 100, 150, 200, 250, 300, 350, 400 (°C) or a numerical range consisting of any two of them.

[0025] As a preferred embodiment, 2 The preheating temperature is 100°C to 400°C, including but not limited to any one of 100, 150, 200, 250, 300, 350, 400 (°C) or a numerical range consisting of any two of them.

[0026] As a more preferred embodiment, TiCl 4 、CaCO 3 and O 2 The difference in preheating temperature of any two raw materials is ≤100°C; avoid excessive temperature difference which may cause strong heat conduction when the raw materials converge, causing large fluctuations in the flow rate of the raw material gas introduced, and thus leading to uneven gas flow rate; when local high-speed airflow is caused, it may cause unevenness of the vapor deposition reaction, and the final titanium dioxide / calcium oxide composite material will perform poorly in terms of particle size and coating thickness.

[0027] As a preferred embodiment, the temperature of the vapor deposition reaction is 100°C to 400°C, including but not limited to any one of 100, 125, 150, 175, 200, 225, 250, 275, 300, 325, 350, 375, 400 (°C) or a numerical range consisting of any two of them.

[0028] As a more preferred embodiment, TiCl 4 、CaCO 3 and O 2 The difference between the preheating temperature of any one of the raw materials and the temperature of the vapor deposition reaction is ≤100°C.

[0029] As a preferred embodiment, the preheated CaCO 3 Sent to the reactor, and then TiCl 4 and O 2 sent to a reaction furnace for vapor deposition reaction; in some optional embodiments, TiCl 4 and O 2 Through two independent gas delivery pipelines to the feed end of the reactor, or TiCl 4 and O 2 The preheated CaCO 3 Sent to the reactor until CaCO appears at the discharge end of the reactor. 3 After the gas flow, TiCl 4 and O 2 The vapor deposition reaction is carried out, and after a period of time (depending on the volume of the reaction furnace), the titanium dioxide / calcium oxide composite material is collected at the discharge end of the reaction furnace.

[0030] As a preferred embodiment, the vapor deposition reaction is carried out in a closed reaction furnace, and the preheated CaCO 3 、TiCl 4 and O 2 They are transported to the reaction furnace respectively to form continuous vapor deposition, and a titanium dioxide / calcium oxide composite material is continuously obtained at the outlet of the reaction furnace.

[0031] As a preferred embodiment, CaCO 3 、TiCl 4 and O 2 The ratio of feed speed is (4~6):(1~1.5):(0.2~0.4).

[0032] As a more preferred embodiment, CaCO 3 The feeding conveying speed is 4t / h to 6t / h, including but not limited to any one of 4, 4.2, 4.5, 4.8, 5, 5.2, 5.5, 5.8, 6 (t / h) or a numerical range consisting of any two of them.

[0033] As a more preferred embodiment, TiCl 4 The feed conveying speed is 1.1 t / h to 2 t / h, including but not limited to any one of 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2 (t / h) or a numerical range consisting of any two of them.

[0034] As a more preferred embodiment,2 The feeding conveying speed is 0.2t / h to 0.4t / h, including but not limited to any one of 0.2, 0.22, 0.24, 0.26, 0.28, 0.3, 0.32, 0.34, 0.36, 0.38, 0.4 (t / h) or a numerical range consisting of any two of them.

[0035] As a preferred embodiment, CaCO 3 and TiCl 4 The carrier gas is delivered to the reaction furnace, and the carrier gas includes but is not limited to at least one of nitrogen, helium, neon or argon.

[0036] As a more preferred embodiment, the carrier gas has a pressure difference between the feeding end and the discharging end of the reactor to ensure continuous feeding of each material and continuous discharging of the composite material; in some more preferred embodiments, CaCO 3 、TiCl 4 and O 2 The materials are fed into the reactor through different feeding ends through carrier gas, and discharged at the only discharging end; CaCO 3 The pressure difference between the feed end and the discharge end is ≥0.1MPa, TiCl 4 and O 2 The pressure difference between the feeding end and the discharging end is ≥0.05MPa.

[0037] As a preferred embodiment, CaCO 3 The raw material purity is ≥90%, TiCl 4 The raw material purity is ≥90%.

[0038] As a preferred embodiment, CaCO 3 The raw material particle size is 0.3μm~0.5μm.

[0039] As a preferred embodiment, the preheating method includes but is not limited to hot air furnace heating or superheated steam heating.

[0040] As a preferred embodiment, the heating method of the vapor deposition reaction includes but is not limited to heating by electric heating wire, heating by electromagnetic heater or heating by hot air furnace.

[0041] As a preferred embodiment, the preheated TiCl 4 Gas and O 2 Gas in CaCO 3 The surface of the particles then forms a layer of TiO through a vapor deposition reaction. 2Thin film; the residence time required for the deposition reaction is relatively short, with an average residence time of 10ms to 2s; in some more preferred embodiments, the average residence time is 10ms to 80ms.

[0042] As a preferred embodiment, at any time during the vapor deposition reaction, the CaCO 3 and TiCl 4 The mass ratio of TiO2 is ≤3.8, so as to ensure that the TiO2 in the titanium dioxide / calcium oxide composite material 2 The coating layer accounts for ≥10wt.%, thereby avoiding defects such as incomplete coating or too thin coating layer.

[0043] As a preferred embodiment, at any time during the vapor deposition reaction, the TiCl 4 and O 2 The mass ratio of TiCl 4 and O 2 The reaction is incomplete and the excess O 2 To ensure TiO 2 Generation of.

[0044] The second aspect of the present invention is to provide a titanium dioxide / calcium oxide composite material, which is prepared based on the preparation method of the titanium dioxide / calcium oxide composite material as described in the first aspect.

[0045] The third aspect of the present invention is to provide the use of the titanium dioxide / calcium oxide composite material as described in the second aspect in pigments, fillers, foods, battery materials or photocatalysis. It is understood that the above-mentioned uses include but are not limited to a pigment product, filler material, food, battery material, photocatalytic material and preparation method thereof containing the titanium dioxide / calcium oxide composite material, and the products or preparation methods involved may be conventional or unconventional, but when containing the titanium dioxide / calcium oxide composite material of the present invention, it can be used as an embodiment of the use of the present invention.

[0046] Example 1

[0047] This embodiment is carried out in a closed heating furnace. An electric heating wire heating system and a corresponding digital temperature control system are arranged in the furnace. The heating furnace uses three different inlet feed ports and a single outlet discharge port. The three inlet feed ports are used for TiCl 4 、CaCO 3 and O 2 of feed and is connected to three raw material preheating furnaces.

[0048] S1: Set TiCl 4 、CaCO 3 and O2 The preheating temperature is 200°C; the reaction temperature of the closed heating furnace is set to 250°C.

[0049] S2: N 2 CaCO is introduced into the heating furnace as carrier gas 3 , CaCO 3 The feed conveying speed is 5t / h and the carrier gas flow rate is 15m 3 / h.

[0050] S3: After a stable airflow appears at the outlet, TiCl is introduced into the heating furnace through the other two feed ports. 4 and O 2 ; TiCl 4 The feeding speed is 1.3t / h, TiCl 4 The carrier gas N 2 Flow rate: 36m 3 / h,O 2 The feeding and conveying speed is 0.26t / h.

[0051] S4: After a stable airflow appears at the outlet, the outlet material is collected and filtered through a microfilter to obtain a solid phase product. After testing, the CaCO 3 The pressure difference between the feeding end and the discharging end is 0.2MPa, TiCl 4 The pressure difference between the feeding end and the discharging end is 0.06MPa.

[0052] Based on the TiO 2 -CaCO 3 Inorganic composite materials were tested by SEM and EDS, such as Figure 1 The material microstructure image under scanning electron microscope is shown in FIG. Figure 2 The figure shows the element distribution diagram obtained by the energy spectrometer. Figure 2 (a) Provides signal response diagrams for all elements, Figure 2 (b) provides a calcium-independent distribution map. Figure 2 (c) provides a separate distribution map of titanium; Figure 3 The figure shows the energy spectrum obtained by the energy spectrometer.

[0053] Example 2

[0054] It is basically the same as Example 1, except that in step S1: TiCl 4 、CaCO 3 and O 2 The preheating temperatures are 320°C, 330°C and 350°C; the reaction temperature of the closed heating furnace is set at 400°C.

[0055] Example 3

[0056] It is basically the same as Example 1, except that in step S2: CaCO 3 The feeding speed is 4t / h; in step S3: TiCl 4 The feeding and conveying speed is 1.1t / h.

[0057] Example 4

[0058] It is basically the same as Example 1, except that in step S2: CaCO 3 The feeding speed is 5.6t / h; in step S3: TiCl 4 The feeding and conveying speed is 1.5t / h.

[0059] Comparative Example 1: CaCO 3 , purity 95%.

[0060] Comparative Example 2: TiO 2 , purity 95%.

[0061] Comparative Example 3

[0062] It is basically the same as Example 1, except that in step S2: CaCO 3 The feeding rate is 6.2t / h; at this time, the CaCO 3 and TiCl 4 The mass ratio is 4.77 (>3.8).

[0063] Comparative Example 4

[0064] It is basically the same as Example 1, except that in step S3: TiCl 4 The feeding speed is 1t / h; at this time, the CaCO 3 and TiCl 4 The mass ratio is 5 (>3.8).

[0065] Test example

[0066] The inorganic composite materials prepared in each embodiment and comparative example were tested, and the average particle size and refractive index were obtained by testing with a Malvern 3000 laser particle size analyzer, and the whiteness was obtained by testing with a DATA COLOR 800. The test results are shown in Table 1 below.

[0067] Table 1

[0068]

[0069]

[0070] Although the present invention has been illustrated and described with specific embodiments, it should be appreciated that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Those skilled in the art should understand that the technical solutions described in the above embodiments may be modified, or some or all of the technical features thereof may be replaced by equivalents without departing from the spirit and scope of the present invention. However, these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention. Therefore, this means that all such replacements and modifications within the scope of the present invention are included in the appended claims.

Claims

1. A method for preparing a titanium dioxide / calcium oxide composite material, characterized in that: The preparation method comprises the following steps: The preheated CaCO3, TiCl4 and O2 are mixed and subjected to vapor deposition reaction to obtain a CaCO3 composite material with TiO2 coated on the surface.

2. The method for preparing the titanium dioxide / calcium oxide composite material according to claim 1, characterized in that: The preheating includes at least one of the following features (a) to (c): (a) The preheating temperature of CaCO3 is 100℃~400℃; (b) the preheating temperature of TiCl4 is 100°C to 400°C; (c) The preheating temperature of O2 is 100℃~400℃.

3. The method for preparing the titanium dioxide / calcium oxide composite material according to claim 1, characterized in that: The temperature of the vapor deposition reaction is 100°C to 400°C.

4. The method for preparing the titanium dioxide / calcium oxide composite material according to claim 1, characterized in that: The preheated CaCO3 is first sent to the reaction furnace, and then TiCl4 and O2 are sent to the reaction furnace for vapor deposition reaction.

5. The method for preparing the titanium dioxide / calcium oxide composite material according to claim 1, characterized in that: CaCO3 and TiCl4 are respectively delivered to the reaction furnace by carrier gas, wherein the carrier gas includes at least one of nitrogen, helium, neon or argon.

6. The method for preparing the titanium dioxide / calcium oxide composite material according to claim 1, characterized in that: The vapor deposition reaction is carried out in a reaction furnace, and the preheated CaCO3, TiCl4 and O2 are continuously transported to the reaction furnace respectively; The heating method for the vapor deposition reaction includes at least one of an electric heating wire, an electromagnetic heater or hot air.

7. The method for preparing the titanium dioxide / calcium oxide composite material according to claim 1, characterized in that: The ratio of the feed rates of CaCO3, TiCl4 and O2 is (4-6):(1-1.5):(0.2-0.4).

8. The method for preparing the titanium dioxide / calcium oxide composite material according to claim 1, characterized in that: When the vapor deposition reaction is carried out, the mass ratio of CaCO3 to TiCl4 in the reaction equipment is ≤3.8; And / or, the mass ratio of TiCl4 to O2 in the reaction equipment is ≤5.

9.

9. The titanium dioxide / calcium oxide composite material obtained by the method for preparing the titanium dioxide / calcium oxide composite material according to any one of claims 1 to 8.

10. Use of the titanium dioxide / calcium oxide composite material as claimed in claim 9 in pigments, fillers, foods, battery materials or photocatalysis.

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