Along with the raising of people's health care consciousness, people are more and more deep with the understanding of the mankind's relation to ultraviolet ray, and especially ultraviolet ray is more and more clearer to the understanding of the mankind's harm.The sunlight middle-ultraviolet lamp divides three sections: UVC (200-280nm), UVB (280-320nm), UVA (320-400nm).The UVC section is absorbed by atmospheric ozone layer, is difficult to arrival point and works the mischief in the face of the mankind; And UVB section energy is higher, and human body according under shining, can cause skin erythema, inflammation at the long-time sun, even causes skin carcinoma; The UVA section much larger than UVB, can cause skin aging, reticular tissue canceration etc. according to solarization to the penetrance of skin for a long time.Simultaneously, ultraviolet ray also can cause problems such as polymer materials takes place to wear out, variable color, causes shorten its work-ing life, or the like.Therefore, in the world developed country protection, shielding ultraviolet rays is as a crucial problem.Ultraviolet screening agent is divided into organic and inorganic two big classes again.Inorganic anti ultraviolet agent, especially nano titanium oxide its because of having chemical stability, thermostability, nontoxic, tasteless, nonirritant, long-lasting, gain great popularity in recent years.
Titanium dioxide has sharp titanium and two kinds of crystal formations of rutile, and rutile-type is better than anatase titanium dioxide on weather resistance, uvioresistant performance.Therefore, more about the research document of nm-class rutile-type TiO 2 in recent years.Chinese patent CN1217297A discloses a kind of nm-class rutile-type TiO 2 preparation method, it is raw material that this method adopts titanium sulfate, titanyl sulfate, metatitanic acid, yellow soda ash is precipitation agent, the gained presoma was calcined 2 hours down at 800~900 ℃, can get rutile content greater than 95%, grain size is at the titanium dioxide powder of 20~50nm.Patent CN1192992A discloses a kind of method of Preparation by Uniform Precipitation nm-class rutile-type TiO 2, this method is raw material with the metatitanic acid, urea is precipitation agent, and presoma needs 800~1000 ℃ of calcinings just can make rutile titanium dioxide in 2.5~3.5 hours.The method of above-mentioned two patent reports all need be passed through the high-temperature calcination process, thereby make process complications, production cost improves, therefore for fear of the high temperature phase inversion, simplify technology, reduce cost, patent CN1248550A discloses and has prepared the nanocrystalline method of rutile titanium dioxide under a kind of room temperature, it is raw material that this method adopts titanium tetrachloride, adds mineral acid control hydrolysis speed, makes the titanium dioxide powder of grain size at 7~100nm.Though this method is avoided the high temperature phase inversion, raw materials used costliness.Patent CN1114949A discloses a kind of preparation method of high pure and ultra-fine rutile titanium dioxide, adopting ilmenite and technical hydrochloric acid is raw material, produce certain density titanium liquid, add two kinds of organism and carry out ordinary-pressure hydrolysis, be prepared into the rutile titanium dioxide powder of 38~45nm.The part material that this method is used is organic reagent (as ethylene glycol monomethyl ether), and raw materials used costliness needs organic reagent to reclaim again, and the possibility of secondary pollution is arranged; Patent US5840111 discloses a kind of preparation method of nano titanic oxide sol; ultimate principle is a raw material for adopting titanyl sulfate; mix with alkali throw out; again with hydrochloric acid flocculate TiO 2 sol, this colloidal sol is suitable as the ultraviolet protective agent of makeup, polymkeric substance, silicone resin, paint.
The objective of the invention is to disclose a kind of preparation method, to overcome the above-mentioned defective that prior art exists with nm-class rutile-type TiO 2 powder of excellent shielding ultraviolet rays function.
Design of the present invention is such:
But in order to obtain the shielding ultraviolet rays superior performance, nm-class rutile-type TiO 2 that production cost is low and suitability for industrialized production, the contriver adopts the liquid phase neutralisation to produce, and production technique is optimized.
According to above-mentioned design, the technical scheme that the present invention proposes in turn includes the following steps: the sedimentary preparation of (1) titanium hydroxide: with titaniferous solution and alkali lye hybrid reaction, make the titanium hydroxide throw out;
Said titaniferous solution is a kind of in titanyl sulfate, titanium sulfate or the metatitanic acid, and its concentration is 50~250g/l;
Said alkali lye is generally sodium hydroxide, ammoniacal liquor, and volatile salt, bicarbonate of ammonia, yellow soda ash, sodium bicarbonate, potassium hydroxide, one or more in salt of wormwood or the saleratus etc., its concentration is 50~250g/l;
Titaniferous solution and alkali lye can add simultaneously, also can the dropping mode add, and titaniferous solution can be added in the alkali lye or add in the titaniferous solution with alkali lye, and temperature of reaction is controlled at 0~80 ℃, and terminal point pH is controlled at 5~10, in and the time be 0.5~3 hour;
(2) precipitation peptization course: reaction product is filtered, and washing gets filter cake, and the filter cake making beating adds peptizing agent, and consumption is 0.1~10 times of titanium dioxide amount, and temperature is controlled at 30~100 ℃, 0.5~2 hour time, makes anatase crystal type change rutile crystal type into;
Said peptizing agent is generally the monobasic mineral acid, preferably hydrochloric acid or nitric acid;
(3) last handling process: the filtration washing products therefrom, drying, pulverize titanium dioxide powder.
As seen from Figure 1, said nano-titanium dioxide powder, its pattern are that (the crystal grain length-to-diameter ratio is 20~15: 1), or granular (grain size is 15~30nm) to needle-like, or spherical (grain size is 15~30nm);
As seen from Figure 2, above-mentioned nano-titanium dioxide powder rutile-type diffraction peak is sharp-pointed, does not have the anatase titanium dioxide diffraction peak, and rutile content is greater than 95% as calculated;
As seen from Figure 3, the shielding ultraviolet rays ability is strong by (280~320nm) and visible light transmissivity height (400~700nm).To test powder and be scattered in the water, be configured to the dispersion liquid of 100ppm, on CRT-760 type ultraviolet/visible spectrophotometer, measure.
Said nano-titanium dioxide powder is suitable as the ultraviolet screening agent of makeup, plastics (agricultural film, packaging material for food, engineering plastics etc.), pottery, fiber, coating, paper, woodenware etc.
By above-mentioned disclosed design and technical scheme as seen, the said nm-class rutile-type TiO 2 of the present invention has that preparation cost is low, and technology is simple, and ultraviolet-resistent property is good, and the visible light permeability height is easy to the characteristics of suitability for industrialized production, has very wide application prospect.To the relevant details of preparation process be described further by example below.Embodiment 1
With concentration be the sodium hydroxide solution of 50g/l to add concentration be in the titanium sulfate solution of 50g/l, temperature of reaction is 20 ℃, in and 2 hours time, terminal point PH is 5, the throw out that makes filters, washing, up to 0.1%BaCl
2Check till the no white precipitate; With filter cake making beating, it is molten that the concentration that adds 0.1 times of titanium dioxide weight is that 1: 1 hydrochloric acid carries out acid, 50 ℃ of temperature, and 1 hour time, the sedimentation and filtration that makes washing is till checking no white precipitate with 0.1%AgCl; The precipitation place 105 ℃ of following dryings after, pulverize nano-titanium dioxide powder.
The about 10nm of the grain size of gained powder, specific surface area (BET) 150m
2/ g, rutile content are greater than 90%, and pH is 7~8, and content of titanium dioxide is greater than 98%, and moisture is less than 1.0%, and burning decrement is less than 1.0%, and screenings is less than 0.01%, and the shielding ultraviolet rays ability is (maximum absorption band 282nm) by force, and the visible light transmissivity height.Embodiment 2
With concentration be the sodium hydroxide of 150g/l to add concentration be in the titanium sulfate solution of 50g/l, temperature of reaction is 70 ℃, in and 3 hours time, terminal point pH is 5, the precipitation that makes is filtered, is washed, up to 0.1%BaCl
2Check till the no white precipitate; With the filter cake making beating, it is molten that the nitric acid that adding titanium dioxide weight is 2 times carries out acid, 50 ℃ of temperature, and 1 hour time, the sedimentation and filtration that makes washing is till with the no white precipitate of 0.1%AgCl check; The precipitation place 105 ℃ of following dryings after, pulverize nano-titanium dioxide powder.
The about 15nm of the grain size of gained powder, BET 110m
2/ g, rutile content are greater than 90%, and pH is 7~8, and content of titanium dioxide is greater than 98%, and moisture is less than 1.0%, and burning decrement is less than 1.0%, and screenings is less than 0.01%, and the shielding ultraviolet rays ability is (maximum absorption band 305nm) by force, and the visible light transmissivity height.Embodiment 3
With concentration be the sodium hydroxide of 100g/l to add concentration be in the titanium sulfate solution of 250g/l, temperature of reaction is 80 ℃, in and 0.5 hour time, terminal point pH is 7, the precipitation that makes is filtered, is washed, up to 0.1%BaCl
2Check till the no white precipitate; With the filter cake making beating, it is molten that the hydrochloric acid that adding titanium dioxide weight is 5 times carries out acid, 90 ℃ of temperature, and 1 hour time, the sedimentation and filtration that makes washing is till with the no white precipitate of 0.1%AgCl check; The precipitation place 130 ℃ of following dryings after, pulverize nano-titanium dioxide powder.
The about 20nm of the grain size of gained powder, BET 90m
2/ g, rutile content are greater than 95%, and pH is 7~8, and content of titanium dioxide is greater than 98%, and moisture is less than 1.0%, and burning decrement is less than 1.0%, and screenings is less than 0.01%, and the shielding ultraviolet rays ability is (maximum absorption band 316nm) by force, and the visible light transmissivity height.Embodiment 4
With metatitanic acid 400g, add sulfuric acid dissolution after, concentration be the vitriol oil titanium liquid of 280g/l, be diluted to the titanyl sulfate that concentration is 50g/l; 1: 1 ammoniacal liquor of concentration is added in the above-mentioned solution, and temperature of reaction is 60 ℃, in and 1 hour time, terminal point pH is 7, the precipitation that makes is filtered, is washed, up to 0.1%BaCl
2Check till the no white precipitate; With the filter cake making beating, it is molten that the nitric acid that adding titanium dioxide weight is 0.7 times carries out acid, 50 ℃ of temperature, and 3 hours time, the sedimentation and filtration that makes washing is till with the no white precipitate of 0.1%AgCl check; The precipitation place 105 ℃ of following dryings after, pulverize nano-titanium dioxide powder.
The about 25nm of the grain size of gained powder, BET 75m2/g, rutile content is greater than 95%, pH is 7~8, and content of titanium dioxide is greater than 98%, and moisture is less than 1.0%, burning decrement is less than 1.0%, screenings is less than 0.01%, and the shielding ultraviolet rays ability is (maximum absorption band 320nm) by force, and the visible light transmissivity height.Embodiment 5
With metatitanic acid 400g, add sulfuric acid dissolution after, concentration be the vitriol oil titanium liquid of 280g/l, be diluted to the titanyl sulfate that concentration is 150g/l; With concentration is that the potassium hydroxide solution of 100g/l adds in the above-mentioned solution, and temperature of reaction is 40 ℃, in and 1 hour time, terminal point pH is 8, the precipitation that makes is filtered, is washed, up to 0.1%BaCl
2Check till the no white precipitate; With the filter cake making beating, it is molten that the hydrochloric acid that adding titanium dioxide weight is 6 times carries out acid, 70 ℃ of temperature, and 1 hour time, the sedimentation and filtration that makes washing is till with the no white precipitate of 0.1%AgCl check; The precipitation place 110 ℃ of following dryings after, pulverize nano-titanium dioxide powder.
The about 15nm of the grain size of gained powder, BET 105m
2/ g, rutile content are greater than 95%, and pH is 7~8, and content of titanium dioxide is greater than 98%, and moisture is less than 1.0%, and burning decrement is less than 1.0%, and screenings is less than 0.01%, and the shielding ultraviolet rays ability is strong, (maximum absorption band 290nm), and visible light transmissivity height.Embodiment 6
With metatitanic acid 400g, add sulfuric acid dissolution after, concentration be the vitriol oil titanium liquid of 280g/l, being diluted to concentration is the 50g/l titanyl sulfate; Sodium hydroxide and sodium bicarbonate mixing solutions (mol ratio is 1: 1) are added in the above-mentioned solution, and temperature of reaction is 60 ℃, in and 2 hours time, terminal point pH is 7, the precipitation that makes is filtered, is washed, up to 0.1%BaCl
2Check till the no white precipitate; With the filter cake making beating, it is molten that the nitric acid that adding titanium dioxide weight is 5 times carries out acid, 50 ℃ of temperature, and 3 hours time, the sedimentation and filtration that makes washing is till with the no white precipitate of 0.1%AgCl check; The precipitation place 105 ℃ of following dryings after, pulverize nano-titanium dioxide powder.
The about 20nm of the grain size of gained powder, BET 86m
2/ g, rutile content are greater than 95%, and pH is 7~8, and content of titanium dioxide is greater than 98%, and moisture is less than 1.0%, and burning decrement is less than 1.0%, and screenings is less than 0.01%, and the shielding ultraviolet rays ability is (maximum absorption band 320nm) by force, and the visible light transmissivity height.Embodiment 7
Adopt the method identical with embodiment 1, but the mixed ammonium/alkali solutions (1: 1, mol ratio) of employing volatile salt and ammoniacal liquor, the about 20nm of the grain size of prepared powder, BET 80m
2/ g, rutile content are greater than 95%, and PH is 7~8, and content of titanium dioxide is greater than 98%, and moisture is less than 1.0%, and burning decrement is less than 1.0%, and screenings is less than 0.01%, and the shielding ultraviolet rays ability is (maximum absorption band 325nm) by force, and the visible light transmissivity height.