anatase Titanium dioxideIt belongs to pigment grade titanium dioxide with strong hiding power, high coloring power and good weather resistance.Mainly used in rubber, plastic, paper making, printing inkcoatingAnd chemical fiber and other industrial sectors.
The scientific name of titanium dioxide istitania(Titanium Dioxide), titanium dioxide has rutile and anatase crystal forms.Rutile titanium dioxide, namely R-type titanium dioxide;Anatase titanium dioxide, namely type A titanium dioxide.
Anatase titanium dioxide is an excellent white powder pigment with good light scattering ability, so it has good whiteness, high coloring power, strong hiding power, non-toxic and tasteless, no irritating effect on human body, and is widely used in many industrial fields, such as coatings, plastics, paper making and printing ink.
Basic performance
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Anatase titanium dioxide, chemical name: titanium dioxide, molecular formula: Ti02, molecular weight: 79.88.White powder, relative density 3.84.Melting point 1560 ℃.Water absorption is 0.2%.It is heated at high temperature (>700 ℃) and transformed into rutile crystal.The melting point is about 1800 ℃.The refractive index is 2.55.The average particle size is 0.15~0.23um.Mohs hardness is 5~6.Stable chemical properties, light resistance, heat resistance, dilute acid resistance, dilute alkali resistance.It has strong coloring power (hiding power) and dispersing power.The durability is not as good as rutile titanium dioxide, the light resistance is poor, and the adhesive layer is easy to be powdered after it is combined with the resin.It is yellow when the temperature is higher than 400 ℃.Insoluble in water, organic acid and inorganic acid, soluble in concentrated sulfuric acid, alkali and hydrofluoric acid.Non toxic, the maximum allowable concentration in the air is 10mg/m3.
Physicochemical properties
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physical property
Among the commonly used white pigments, anatase titanium dioxide has the smallest relative density.Anatase will change into rutile at high temperature[1]Therefore, the melting point and boiling point of anatase titanium dioxide do not actually exist.The dielectric constant of anatase titanium dioxide is relatively low, only 48.The Mohs hardness of anatase titanium dioxide is 5.5~6.0, so anatase titanium dioxide is used in chemical fiber matting to avoid abrasion of spinneret holes.Type A titanium dioxide has good whiteness, but its coloring force is only 70% of that of type R. In terms of weather resistance, type A titanium dioxide test pieces start to crack or flake after only one year, while type R titanium dioxide test pieces have little change in appearance after ten years.Since R type titanium dioxide has better coloring power and weather resistance, it is better to use R type titanium dioxide for plastic coloring.
chemical property
Anatase titanium dioxide is a kind of acidic amphoteric oxide with extremely stable chemical properties.It hardly reacts with other elements and compounds at room temperature, and has no effect on oxygen, ammonia, nitrogen, hydrogen sulfide, carbon dioxide, sulfur dioxide. It is insoluble in water, fat, dilute acid, inorganic acid and base, and only soluble in hydrofluoric acid.However, under the action of light, titanium dioxide can produce continuousRedox reaction, with photochemical activity.The anatase titanium dioxide is particularly obvious under ultraviolet irradiation, which makes it not only a photosensitive oxidation catalyst for some inorganic compounds, but also a photosensitive reduction catalyst for some organic compounds.
Preparation method
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The manufacturing process of titanium dioxide includes sulfuric acid method and chlorination method, both of which can produce type A and type R titanium dioxide.The sulfuric acid process began in 1931, and the chlorination process began to produce Type A in 1975.The oxidation step in the chlorination process controls the particle size distribution and crystal structure, so that it can produce titanium dioxide with high hiding power, blue background and high coloring strength.At present, domestic anatase titanium dioxide is only produced by sulfuric acid process, and chlorination process is only used for the production of some rutile titanium dioxide[2]。
1. The general process of sulfuric acid method: firstly, the ferrotitanium ore powder is acidulated with concentrated sulfuric acid to generate titanium bisulfate.Then it is hydrolyzed to metatitanic acid.Finally, the titanium dioxide product is obtained by burning and crushing.Sulfuric acid process has the advantages of rich raw materials, low price and easy access, mature process, simple equipment and easy operation.The disadvantages are long process flow, intermittent operation and large discharge of waste by-products.
manufacturing process
2. General process of chlorination: natural rutile or high titanium slag raw materials are mixed with carbon or petroleum coke for high-temperature chlorination.Titanium tetrachloride is generated and then oxidized at high temperature to generate titanium dioxide.Finally, titanium dioxide is obtained by filtering, washing, drying and crushing.
purpose
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Titanium dioxide is widely used in coatings, plastics, rubber, ink, paper, chemical fiber, ceramics, daily chemicals, medicine, food and other industries.Coatings are divided into anatase and rutile, and non coating titanium dioxide is also subdividedEnamel grade titanium dioxide、Ceramic grade titanium dioxide, electronic ceramic grade titanium dioxide, welding rod grade titanium dioxide, alloy grade titanium dioxide, glass grade titanium dioxide, etc.
Anatase titanium dioxide is mainly used in the following aspects[3]: Titanium dioxide for paper making generally uses anatase titanium dioxide without surface treatment, which can play the role of fluorescence and whitening, and increase the whiteness of paper.Titanium dioxide used in the ink industry can be rutile or anatase, which is an indispensable white pigment in advanced inks.Titanium dioxide used in textile and chemical fiber industries is mainly used as a matting agent. Since the anatase is softer than the golden red type, the anatase type is generally used.Titanium dioxide is not only used as colorant in the rubber industry, but also has the functions of reinforcement, anti-aging and filling. Generally, it is mainly anatase.
