CN1264754C - Preparation method of nanometer rutile type titanium dioxide - Google Patents

Abstract

A kind of preparation method of nanometer rutile type titanium dioxide, it comprises the following steps: step 1: in wet H ₂ TiO ₃ (water content is 58-70%), add the deionized water of 2-5 times of quality, after beating, at room temperature Next, add ammonium carbonate to neutralize, after neutralization, filter and separate, add deionized water to the precipitate, disperse and beat, wash, and wash until the pH of the filtrate is 7-8. Step 2: Purified H ₂ TiO ₃ , Add NaOH, stir the alkali solution at 85-118°C for 2.5-4.5hrs, separate the alkali solution, and wash the precipitate with deionized water. Step 3: Add H ₄ TiO ₄ after the alkali solution and washing, and add HCl to the After acid-dissolving at 85-115°C for 60-170 minutes, filter and separate the acid solution, and wash the precipitate with deionized water until the pH of the filtrate = 7-8. Dry at 120°C, grind or slightly disperse to obtain nano-rutile TiO ₂ powder. The characteristics of the method are: no crystal accelerator is added; the nanometer rutile TiO ₂ is prepared at a lower temperature, the cost is low, and almost 100% of the prepared nanometer TiO ₂ is rutile.

Description

A kind of preparation method of nanometer rutile type titanium dioxide

1. Technical field

The invention relates to a method for preparing nanometer rutile titanium dioxide with metatitanic acid.

2. Background technology

Titanium dioxide (TiO ₂ ) is a polymorphic compound that is non-toxic and harmless to the human body, and has three crystal forms: brookite, anatase and rutile. The crystal form of brookite-type TiO ₂ is unstable, and there is no report of industrial application so far. The structure of rutile TiO ₂ is more stable and compact than that of anatase TiO ₂ , and its hardness, density, dielectric constant, refractive index, hiding power, tinting power, and ability to absorb ultraviolet rays are all higher. Since the reflectivity and photooxidative catalytic activity of anatase TiO ₂ in the visible short-wave part are higher than those of rutile TiO ₂ , when used as a coloring pigment, its weather resistance and chalking resistance are worse than those of rutile TiO 2 . Therefore, in the fields of advanced paints, sunscreen cosmetics, fresh-keeping packaging, fine ceramics and porcelain dielectric capacitors, rutile TiO ₂ has wider applications and higher commercial value than anatase TiO ₂ .

Nano-rutile TiO ₂ is an extremely fine grain with a particle size in the range of 1-100nm. It has functions such as surface effect, quantum size effect and macroscopic quantum tunneling effect that micron-sized grains and bulk crystals do not have, so it shows extremely Good chemical resistance, photocatalytic activity and UV resistance. Therefore, in addition to the above-mentioned applications, it is also used as a photosensitive element, a photolytic water splitting device, an anti-fog glass, a catalyst for photodegradation of organic matter, a gas sensor, a temperature sensor, and a magnetic recording material, and has a good application prospect.

The methods for synthesizing nano-rutile TiO ₂ at home and abroad mainly include liquid phase or gas phase hydrolysis of titanium alkoxide (Ti(OR) ₄ ), high temperature gas phase oxidation of titanium tetrachloride (TiCl ₄ ), and gas phase hydrogen-oxygen flame hydrolysis. And liquid phase method and titanium oxysulfate (TiOSO ₄ ) liquid phase peptization method, etc. The price of Ti(OR) ₄ , TiCl ₄ and other raw materials used is very expensive, but the use of TiCl ₄ as raw material requires extremely high corrosion resistance of equipment, high investment costs, and it is difficult to avoid environmental pollution. Therefore, in this case, in order to prepare nano-rutile TiO ₂ , some domestic patents have successively announced the development results using titanium sulfate (Ti(SO ₄ ) ₂ ), TiOSO ₄ and H ₂ TiO ₃ . For example, in CN 104463C, H ₂ TiO ₃ added with rutile crystal form promoter is used to disperse and emulsify with polyethylene glycol and heat treatment at 700-800°C for 1.5-3hr to obtain rutile TiO ₂ with a specific surface area of >10m ² /g, particle size ~ 100nm. This is an earlier patent report in China that adopts the sol-gel method, adds a crystal accelerator, and undergoes high-temperature roasting in an electric furnace to transform crystals. Its disadvantages are: when the calcination temperature is low, it is difficult to transform the crystal or only part of the crystal is transformed into rutile; when the calcination temperature is high, the crystal is transformed well, but the grain grows beyond the nanoscale range, and the listed specific surface area data and electron microscope photos This situation is also clearly illustrated. In addition, the production cost is high due to the large consumption of electric energy in the roasting. Patents: CN 1076319C; CN1078181C; CN 1343745A and CN 1308022A etc. reported the use of: uniform precipitant (NH ₂ ) ₂ CO; or adding dispersing agent zinc sulfate; or adding monoethanolamine dispersant and adding crystal form accelerator oxygen chloride Titanium; or add organic surface treatment agent salicylic acid and add No. 60-90 industrial organic oil to extract TiO ₂ , and then prepare nano-rutile TiO ₂ through high-temperature roasting in different temperature ranges in the range of 560-1000°C one by one. CN 1431154A, use Ti(SO ₄ ) ₂ , TiOSO ₄ and H ₂ TiO ₃ as raw materials and alkali to make orthotitanic acid (Ti(OH) ₄ ), and then use organic complexes (oxalic acid, EDTA or tartaric acid, etc.) The titanium organic complex solution is processed to obtain the target product: liquid nano-titanium dioxide precursor. After the precursor is heat-treated at 700-800° C. for 1 hour, nanometer rutile titanium dioxide is produced. When CN 1124983C adopts Ti(SO ₄ ) ₂ , TiOSO ₄ and H ₂ TiO ₃ as raw materials for preparation, H ₂ TiO ₃ is first treated with H ₂ SO ₄ to make TiOSO ₄ , and then treated with alkali at 0-80°C function, make Ti(OH) ₄ , and then use HCl or HNO ₃ at 30-100°C to make nano-rutile TiO ₂ without high-temperature roasting, specific surface area of 80-150m ² /g, and rutile content >90-95% . Seo Dong-Seok et al. [J.Kor.Ceram.Soc., 38(4), 331-336(2001)] reported the use of TiCl ₄ and NH ₄ OH to make titanium hydroxide precipitation, and then with NaOH 60-80 ℃, and after washing, react with HCl at 60-100 ℃ to make nano-rutile TiO ₂ with a specific surface area as high as 240-250m ² /g. CN 1142100C uses TiOSO ₄ as raw material, after alkali precipitation, washing, and then treating with nitric acid to make titanyl nitrate, adding crystal form accelerator (EDTA, salicylic acid, citric acid...etc.), 95- 105°C, 0.5-4hr under normal pressure hydrolysis to prepare nano-rutile TiO ₂ . CN1324767A, using H ₂ TiO ₃ as raw material, adding alkali to make Ti(OH) ₄ , adding H ₂ SO ₄ to dissolve and generate Ti(SO ₄ ) ₂ , then adding crystal form accelerator (0.2% zinc oxide, 0.1% magnesium oxide ) at 70-100°C for 3 hours to obtain nano-TiO ₂ sol, coagulate with alkaline solution, wash away SO ₄ ^2- and Na ⁺ , and add HCl to peptize. Centrifuge and dry at 80-100°C to make nano-rutile TiO ₂ . CN 1363520A uses Ti(SO ₄ ) ₂ as raw material, uses ammonium tetraammine zinc(II) as neutralizing agent to prepare hydrolysis seed crystal, obtains H ₂ TiO ₃ through hydrolysis, and adds alkali to obtain Ti(OH) ₄ . Add acid to prepare titanium dioxide sol, add coagulant (polyethylene glycol, triethanolamine...etc _. )

3. Contents of the invention

The present invention is obtained after a large amount of research and development work on the basis of domestic patent announcements and relevant literature reports. The purpose of the present invention is to provide a kind of: titanium raw material is cheap and easy to obtain; Process flow is simple and easy to control; Product cost is low, purity is high, quality is stable, is convenient to the method for industrialized production of nano-rutile TiO ₂ .

Technical scheme of the present invention is as follows

A kind of preparation method of nanometer rutile type titanium dioxide, it comprises the following steps:

Step 1: Add 2-5 times the amount of deionized water to the wet H ₂ TiO ₃ (water content is 58-70%) produced by the sulfuric acid titanium dioxide factory, after beating, at room temperature, according to the mass ratio W _{( NH4)2CO3} : W _H2TiO = 0.01-0.08 Add ammonium carbonate [(NH ₄ ) ₂ CO ₃ ], stir vigorously, neutralize, (NH ₄ ) ₂ CO ₃ is neutralized and separated by filtration, add deionized water to the precipitate, Stir vigorously, disperse and beat, wash, and wash until the pH of the filtrate is 7-8, so as to remove metal ions, acid liquid and chemically adsorbed SO ₃ in H ₂ TiO ₃ , and obtain after filtration (NH ₄ ) ₂ CO ₃ to treat the purified H ₂ TiO ₃ .

Step 2: With the H ₂ TiO ₃ purified in step 1, when the TiO ₂ content is 200-350g/L, according to the ratio of the amount of substances, M _{TiO 2} : M _NaOH = 1.0: 2.8-4.2, add NaOH, at 85-118 After stirring the alkali solution for 2.5-4.5 hours at °C, separate the alkali solution, wash the precipitate with deionized water until the pH of the filtrate is 7-8, and detect the absence of SO ₄ ^2- ions with 0.5M BaCl ₂ solution.

The chemical reaction formula in the process of alkali dissolution and washing is:

(1)

(2)

Step 3: Dissolve and wash the H ₄ TiO ₄ in step 2, under the content of TiO ₂ 200-350g/L, according to the ratio of the amount of substances, M _TiO 2 : M _HCl = 1.0 : 1.2-2.2, add HCl , after 60-170 minutes of acid dissolution at 85-115°C, filter and separate the acid solution, wash the precipitate with deionized water until the pH of the filtrate = 7-8, and use 0.1NAgNO ₃ solution to detect the absence of Cl ^- ions.

The chemical reaction formula in the acid dissolution process is:

(3)

(4)

(5)

(6)

The dissolution of orthotitanic acid after acid addition, and the adsorption and charging process of the generated Ti ⁴⁺ and TiO ²⁺ with a certain charge on the particles of titanium oxides such as orthotitanic acid, all make the particles of titanium oxides dispersed. And it is stable in the solution in the form of colloidal particles, and under the condition of colloidal particles, nano-rutile TiO ₂ is generated after heating, aging and crystal transformation.

Step 4: The acid-dissolved and washed precipitate in step 3 is dried at 105-120° C., ground or slightly dispersed to obtain nano-rutile TiO ₂ powder.

The method for preparing nanometer rutile titanium dioxide of the present invention is characterized in that no crystal accelerator is added; no emulsifier, complexing agent and dispersant are added; high temperature roasting is not used; H ₂ TiO ₃ is used at a lower reaction temperature Nano rutile TiO ₂ is prepared under low cost, and almost 100% of the prepared nano rutile TiO ₂ is rutile.

4. Description of drawings

Fig. 1 is the XRD spectrogram of the nano-rutile titanium dioxide prepared by the method of the present invention, wherein: 1 is the sample prepared in Example 1, 2 is the sample prepared in Example 2, 3 is the sample prepared in Example 3, and 4 is Example 4 is the sample prepared, 5 is the sample prepared in Example 5, and 6 is the sample prepared in Example 6.

Fig. 2 is the TEM photograph of the nanometer rutile type titanium dioxide prepared by the method of the present invention, wherein: Fig. 2.1 is the sample prepared in embodiment 1, Fig. 2.2 is the sample prepared in embodiment 2, Fig. 2.3 is the sample prepared in embodiment 3, Fig. 2.4 For the sample prepared in Example 4, Figure 2.5 is the sample prepared in Example 5, and Figure 2.6 is the sample prepared in Example 6,

4. Specific implementation

Embodiment one

Add 5 times the amount of deionized water to wet H ₂ TiO ₃ (water content 58-70%), make a slurry, and add (NH ₄ ) ₂ CO at room temperature according to the mass ratio W _(NH4)2CO3 : _{W H2TiO3} = 0.01 _3. Neutralize, fully stir, filter, and separate (NH ₄ ) ₂ CO ₃ washing solution. Add deionized water to stir thoroughly, wash for many times until the pH of the filtrate = 7-8, filter and separate to obtain washed and purified H ₂ TiO ₃ , at a TiO ₂ content of 200g/L, according to the ratio of the amount of substances M _TiO2 : M _NaOH =1.0:2.8 Add NaOH, stir for 4.5 hours in alkaline solution at 85°C, filter and separate the alkaline solution. The precipitate was washed with deionized water, and the filtrate was detected by BaCl ₂ 0.5M solution to contain no SO ₄ ^2- ions, and after pH = 7-8, at a TiO ₂ content of 200g/L, according to the ratio of the amount of substances M _TiO2 : M _HCl = 1.0: 1.2 Add HCl, dissolve in acid at 92°C for 150 minutes, filter, separate the acid solution, wash the precipitate with deionized water until the filtrate pH = 7-8, use 0.1N AgNO ₃ solution to detect the absence of Cl ^- . The resulting precipitate was dried at 105° C., ground or slightly dispersed to obtain nano-rutile TiO ₂ in the form of a white powder, almost 100% of which was rutile. It is determined by XRD to be rutile TiO ₂ (JCPDS 21-1276); TEM photo (35153) has a particle size of 30-60nm and a spindle shape; the specific surface area is 135.9m ² /g.

Embodiment two

Add 2 times the amount of deionized water to wet H ₂ TiO ₃ (water content 58-70%), make a slurry, add (NH ₄ ) ₂ CO at room temperature according to the mass ratio W _(NH4)2CO3 : _{W H2TiO3} = 0.02 ₃ neutralization, the treatment process of purification is identical with embodiment one. Wash and purify the H ₂ TiO ₃ , and add NaOH at a TiO ₂ content of 240 g/L according to M _{TiO 2} : M _NaOH = 1.0: 3.2. After alkali dissolution at 90°C for 4.2.hr, separate the lye. The precipitate was washed with deionized water, and the filtrate was detected by BaCl ₂ 0.5M solution to contain no SO ₄ ^2- ions, and after pH = 7-8, at a TiO ₂ content of 240g/L, press M _{TiO 2} : M _HCl = 1.0 : 1.5 Add HCl, dissolve in acid at 98°C for 100 minutes, and then filter and separate the acid solution. The precipitate was washed with deionized water until the pH of the filtrate was 7-8, and no Cl ^- ions were detected with 0.1N AgNO ₃ solution. The resulting precipitate was dried at 110° C., ground or slightly dispersed to obtain nano-rutile TiO ₂ which was almost 100% rutile in the form of white powder. It is determined by XRD to be rutile TiO ₂ (JCPDS 21-1276); TEM photo (35155) has a particle size of 20-40nm and a spindle shape; the specific surface area is 146.1m ² /g.

Embodiment three

Add 4 times the amount of deionized water to wet H ₂ TiO ₃ (water content 58-70%), make a slurry, add (NH ₄ ) ₂ CO at room temperature according to the mass ratio W _(NH4)2CO3 : _{W H2TiO3} = 0.04 ₃ neutralization, the treatment process of purification is identical with embodiment one. After washing and purifying H ₂ TiO ₃ , when the TiO ₂ content is 270g/L, add NaOH according to the ratio of the amount of substances M _TiO2 : M _NaOH = 1.0:3.8, and stir in alkali solution at 118°C for 4.0.hr, then separate the alkali liquid. The precipitate was washed with deionized water until the filtrate was detected by BaCl ₂ 0.5M solution to contain no SO ₄ ^2- ions, and pH = 7-8, at a TiO ₂ content of 270g/L, according to the ratio of the amount of substances M _TiO2 : M _HCl = 1.0: 2.0 Add HCl, acid dissolve at 112°C for 120 minutes, then filter and separate the acid solution. The precipitate was washed with deionized water until the pH of the filtrate was 7-8, and no Cl ^- ions were detected with 0.1N AgNO ₃ solution. The resulting precipitate was dried at 115° C., ground or slightly dispersed to obtain nano-rutile TiO ₂ in the form of a white powder, almost 100% of which was rutile. It is determined by XRD to be rutile TiO ₂ (JCPDS 21-1276); TEM photo (42288) has a particle size of 50-80nm and a spindle shape; the specific surface area is 157.6m ² /g.

Embodiment four

Add 5 times the amount of deionized water to wet H ₂ TiO ₃ (water content 58-70%), make a slurry, add (NH ₄ ) ₂ CO at room temperature according to the mass ratio W _(NH4)2CO3 : _{W H2TiO3} = 0.05 ₃ neutralization, the treatment process of purification is identical with embodiment one. After washing and purifying H ₂ TiO ₃ , when the content of TiO ₂ is 300g/L, add NaOH according to the ratio of substance amount M _{TiO 2} : M _NaOH = 1.0: 3.5, stir in alkaline solution at 110°C for 3.2.hr, then filter and separate lye. The precipitate was washed with deionized water until the filtrate was detected by BaCl ₂ 0.5M solution to contain no SO ₄ ^2- ions, and pH=7-8, at a TiO ₂ content of 300g/L, according to the ratio of the amount of substances M _TiO2 : M _HCl = 1.0: 1.7 Add HCl, acid dissolve at 115°C for 60 minutes, then filter and separate the acid solution. The precipitate was washed with deionized water until the pH of the filtrate was 7-8, and no Cl ^- ions were detected with 0.1N AgNO ₃ solution. The resulting precipitate was dried at 112° C., ground or slightly dispersed to obtain nano-rutile TiO ₂ in the form of a white powder, almost 100% of which was rutile. It is determined by XRD to be rutile TiO ₂ (JCPDS 21-1276); TEM photo (42289) has a particle size of 30-80nm and a spindle shape; the specific surface area is 142.8m ² /g.

Embodiment five

Add 4 times the amount of deionized water to wet H ₂ TiO ₃ (water content 58-70%), make a slurry, add (NH ₄ ) ₂ CO at room temperature according to the mass ratio W _(NH4)2CO3 : _{W H2TiO3} = 0.06 ₃ neutralization, the treatment process of purification is identical with embodiment one. Wash and purify the H ₂ TiO ₃ , under the TiO ₂ content of 3i20g/L, according to the ratio of the amount of substances M _TiO2 : M _NaOH = 1.0:4.0, add NaOH, stir in alkali solution at 115°C for 2.5.hr, then filter Separate the lye. The precipitate was washed with deionized water until the filtrate was detected by BaCl ₂ 0.5M solution to contain no SO ₄ ^2- ions, and pH=7-8, at a TiO ₂ content of 320g/L, according to the ratio of the amount of substances M _TiO2 : M _HCl = 1.0: 1.9 Add HCl, acid dissolve at 108°C for 106 minutes, then filter and separate the acid solution. The precipitate was washed with deionized water until the pH of the filtrate was 7-8, and no ^Cl- ions were detected with 0.1NAgNO ₃ solution. The resulting precipitate was dried at 118° C., ground or slightly dispersed to obtain nano-rutile TiO ₂ which was almost 100% rutile in the form of white powder. It is determined by XRD as rutile TiO ₂ (JCPDS 21-1276); TEM photo (35151), particle size 30-60nm, spindle shape; specific surface area 142.1m ² /g.

Embodiment six

Add 2 times the amount of deionized water to wet H ₂ TiO ₃ (water content 58-70%), make a slurry, add (NH ₄ ) ₂ CO at room temperature according to the mass ratio W _(NH4)2CO3 : _{W H2TiO3} = 0.08 ₃ neutralization, the treatment process of purification is identical with embodiment one. After washing and purifying H ₂ TiO ₃ , when the content of TiO ₂ is 350g/L, add NaOH according to the ratio of the amount of substances M _{TiO 2} : M _NaOH = 1.0: 4.2, and stir in alkaline solution at 104°C for 3.8.hr, Concerns about separating lye. The precipitate was washed with deionized water until the filtrate was detected by BaCl ₂ 0.5M solution to contain no SO ₄ ^2- ions, and pH = 7-8, at a TiO ₂ content of 350g/L, according to the ratio of the amount of substances M _TiO2 : M _HCl = 1.0: 2.2 Add HCl, acid dissolve at 85°C for 170 minutes, then filter and separate the acid solution. The precipitate was washed with deionized water until the pH of the filtrate was 7-8, and no Cl ^- ions were detected with 0.1N AgNO ₃ solution. The resulting precipitate was dried at 120° C., ground or slightly dispersed to obtain nano-rutile TiO ₂ in the form of a white powder, almost 100% of which was rutile. It is determined by XRD to be rutile TiO ₂ (JCPDS 21-1276); TEM photo (42252) has a particle size of 30-70nm and a spindle shape; the specific surface area is 153.2m ² /g.

Claims (2)

1. the method for making of a nm-class rutile-type TiO 2 is characterized in that it may further comprise the steps:

Step 1: in water content is the wet H of 58-70% ₂TiO ₃In, add the deionized water that 2-5 doubly measures quality, at room temperature, press mass ratio W after the making beating _{(NH4) 2CO3}: W _H2TiO3=0.01-0.08 adds volatile salt, violent stirring, neutralization, (NH ₄) ₂CO ₃Neutralization is after filtering separation adds deionized water in the precipitation, and violent stirring is disperseed making beating, washing, wash to the pH of filtrate be 7-8,

Step 2: with the H of step 1 purifying ₂TiO ₃, at TiO ₂Under the content 200-350g/L, press the ratio of amount of substance, M _TiO2: M _NaOH=1.0: 2.8-4.2, add NaOH, after stirring the molten 2.5-4.5hr of alkali under 85-118 ℃, filtering separation is fallen alkali lye, and the pH=7-8 to filtrate is washed in the precipitate with deionized water washing,

Step 3: with step 2 alkali molten and the washing after H ₄TiO ₄, at TiO ₂Under the content 200-350g/L, press the ratio of amount of substance, M _TiO2: M _HCl=1.0: 1.2-2.2, add HCl, at 85-115 ℃, after sour molten 60-170 minute, filtering separation is fallen acid solution, and precipitate with deionized water is washed the pH=7-8 to filtrate,

Step 4: through the molten throw out that reaches after cleaning of step 3 acid,, grind or dispersion slightly, promptly obtain nano rutile-type TiO 105-120 ℃ of oven dry down ₂Powder.

2. method for making according to claim 1 is characterized in that: step 3 is precipitated to filtrate with deionized water wash and uses 0.1N AgNO ₃Solution detects and does not contain Cl ^-Ion.

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