Titanium Dioxide

physical characteristics

1) Relative density

Among the commonly used White Pigments, Titanium Dioxide has the lowest relative density. Among the white pigments of the same quality, titanium dioxide has the largest surface area and the highest pigment volume.

2) Melting point and boiling point

Because anatase will change into rutile at high temperature, the melting point and boiling point of anatase titanium dioxide actually do not exist. Only Rutile Titanium Dioxide has melting point and boiling point. The melting point of rutile titanium dioxide is 1850 ℃, the melting point in air is (1830 ± 15) ℃, and the melting point in oxygen enrichment is 1879 ℃. The melting point is related to the purity of titanium dioxide. The boiling point of rutile titanium dioxide is (3200 ± 300) ℃, and titanium dioxide is slightly volatile at this high temperature.

3) Dielectric constant

Titanium dioxide has excellent electrical properties because of its high dielectric constant. When determining some physical properties of titanium dioxide, the crystallization direction of titanium dioxide crystal should be considered. The dielectric constant of anatase titanium dioxide is relatively low, only 48.

4) Conductivity

Titanium dioxide has semiconductor properties. Its conductivity increases rapidly with the increase of temperature, and it is also very sensitive to hypoxia. The dielectric constant and semiconductor properties of rutile titanium dioxide are very important to the electronic industry. This property can be used to produce electronic components such as ceramic capacitors.

5) Hardness

According to Mohs hardness scale, rutile titanium dioxide is 6 ~ 6.5 and anatase titanium dioxide is 5.5 ~ 6.0. Therefore, anatase titanium is used in chemical fiber extinction to avoid wear of spinneret holes.

6) Hygroscopicity

Although titanium dioxide has hydrophilicity, its hygroscopicity is not very strong, and rutile type is smaller than anatase type. The hygroscopicity of titanium dioxide is related to its surface area. The large surface area and high hygroscopicity are also related to surface treatment and properties.

7) Thermal stability

Titanium dioxide is a material with good thermal stability.

8) Granularity

The particle size distribution of titanium dioxide is a comprehensive index, which seriously affects the pigment performance and product application performance of titanium dioxide. Therefore, the discussion of hiding power and dispersion can be directly analyzed from the particle size distribution.

The factors affecting the particle size distribution of titanium dioxide powder are complex. The first is the original particle size of hydrolysis. The original particle size is within a certain range by controlling and adjusting the hydrolysis process conditions. The second is the calcination temperature. In the calcination process of metatitanic acid, the particles undergo a crystal transformation period and growth period. Control the appropriate temperature to make the growth particles within a certain range. Finally, the crushing of products. Usually, the transformation of Raymond mill and the adjustment of analyzer speed are used to control the crushing quality. At the same time, other crushing equipment can be used, such as universal mill, air flow mill and hammer mill.


Chemical properties

Titanium dioxide has extremely stable chemical properties and is a kind of acidic amphoteric oxide. It hardly reacts with other elements and compounds at room temperature, has no effect on oxygen, ammonia, nitrogen, hydrogen sulfide, carbon dioxide and sulfur dioxide, is insoluble in water, fat, dilute acid, inorganic acid and alkali, and is only soluble in hydrofluoric acid. However, under the action of light, titanium dioxide can undergo continuous redox reaction and has photochemical activity. This photochemical activity is particularly evident in anatase titanium dioxide under ultraviolet irradiation. This property makes titanium dioxide both a photosensitive oxidation catalyst for some inorganic compounds and a photosensitive reduction catalyst for some organic compounds.

Emergency treatment: isolate the leakage contaminated area and restrict access. It is recommended that emergency treatment personnel wear dust mask (full mask) and general work clothes. To avoid dust, sweep it carefully, put it in a bag and transfer it to a safe place. If there is a large amount of leakage, cover it with plastic cloth and canvas. Collect and recycle it or transport it to the waste treatment site for disposal.

Titanium dioxide (or titanium dioxide) is widely used in various structural surface coatings, paper coatings and fillers, plastics and elastomers. Other applications include ceramics, glass, catalysts, coated fabrics, printing inks, roof paving and flux. According to statistics, the global demand for titanium dioxide reached 4.6 million tons in 2006, including 58% in the coating industry, 23% in the plastic industry, 10% in papermaking and 9% in others. Titanium dioxide can be prepared from ilmenite, rutile and titanium slag. There are two production processes of titanium dioxide: sulfate process and chloride process. The technology of sulfate process is simpler than chloride process, and minerals with low grade and relatively cheap can be used. Today, about 47% of the world's production capacity adopts sulfate process and 53% of the production capacity is chloride process.