Main features of Titanium Dioxide

Titanium dioxide (English name: titanium dioxide), a white pigment whose main component is titanium dioxide (TiO2). The scientific name is titanium dioxide (titanium dioxide) and the molecular formula is TiO2. It is a polycrystalline compound whose particles are regularly arranged and have a lattice structure. It is an important inorganic chemical pigment, especially for coatings, inks, It has important applications in papermaking, plastic rubber, chemical fiber, ceramics and other industries.

1. Physical characteristics

1) Relative density

Among the commonly used white pigments, titanium dioxide has the smallest relative density. Among white pigments of the same quality, titanium dioxide has the largest surface area and the highest pigment volume.

2) Melting point and boiling point

Since the anatase type transforms into the rutile type at high temperatures, the melting point and boiling point of anatase type titanium dioxide actually do not exist. Only rutile titanium dioxide has a melting point and boiling point. The melting point of rutile titanium dioxide is 1850°C, the melting point in air is (1830±15)°C, and the melting point in oxygen enrichment is 1879°C. The melting point is related to the purity of titanium dioxide. The boiling point of rutile titanium dioxide is (3200±300)°C. Titanium dioxide is slightly volatile at this high temperature.

3) Dielectric constant

Due to the high dielectric constant of titanium dioxide, it has excellent electrical properties. When determining certain physical properties of titanium dioxide, the crystal orientation of titanium dioxide crystals should be considered. The dielectric constant of anatase titanium dioxide is relatively low, only 48.

4) Conductivity

Titanium dioxide has the properties of a semiconductor. Its electrical conductivity increases rapidly with the rise 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 electronics industry, and these properties can be used to produce ceramic capacitors and other electronic components.

5) Hardness

According to the scale of Mohs' hardness, rutile titanium dioxide is 6-6.5, and anatase titanium dioxide is 5.5-6.0. Therefore, anatase is used in chemical fiber matting to avoid abrasion of spinneret holes.

6) Hygroscopicity

Although titanium dioxide is hydrophilic, its hygroscopicity is not very strong, and the rutile type is smaller than the anatase type. The hygroscopicity of titanium dioxide has a certain relationship with the size of its surface area. The surface area is large and the hygroscopicity is high. It is also related to the surface treatment and properties.

7) Thermal stability

Titanium dioxide is a substance with good thermal stability.

8) Granularity

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

The factors affecting the particle size distribution of titanium dioxide are more complicated. The first is to hydrolyze the size of the original particle size. By controlling and adjusting the hydrolysis process conditions, the original particle size is within a certain range. The second is the calcination temperature. During the calcination process of metatitanic acid, the particles undergo a crystalline transformation period and a growth period. The appropriate temperature is controlled to keep the growing particles within a certain range. Finally, the product is crushed. The Raymond mill is usually modified and the analyzer speed is adjusted to control the crushing quality. At the same time, other crushing equipment can be used, such as: universal mill, jet mill and hammer mill.

2. Crystal structure

Titanium dioxide has three crystal forms in nature: rutile, anatase and brookite. The brookite type belongs to the orthorhombic crystal system and is an unstable crystal type. It is transformed into a rutile type at a temperature above 650°C, so it has no practical value in industry. The anatase type is stable at room temperature, but will transform to rutile type at high temperature. The conversion strength depends on the manufacturing method and whether there are inhibitors or accelerators added during the calcination process.

It is generally believed that almost no crystal form conversion is carried out below 165°C, and the conversion is very fast when it exceeds 730°C. The rutile type is the most stable crystalline form of titanium dioxide with a compact structure. Compared with the anatase type, it has higher hardness, density, dielectric constant and refractive index. Both the rutile type and the anatase type belong to the tetragonal crystal system, but have different crystal lattices, so the X-ray images are also different. The diffraction angle of the anatase type titanium dioxide is at 25.5°, and the diffraction angle of the rutile type is at 27.5°. The rutile type crystals are slender and prismatic, usually twin crystals; while the anatase type generally approximates a regular octahedron.

Compared with the anatase type, the unit lattice of the rutile type is composed of two titanium dioxide molecules while the anatase type is composed of four titanium dioxide molecules, so its unit lattice is smaller and compact, so it has greater stability It has high refractive index and dielectric constant and low thermal conductivity.

Among the three isomers of titanium dioxide, only the rutile type is the most stable, and only the rutile type can be obtained by thermal conversion. Natural brookite transforms into rutile type at temperatures above 650℃, and anatase can transform into rutile type at around 915℃.

3. 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, and has no effect on oxygen, ammonia, nitrogen, hydrogen sulfide, carbon dioxide, and sulfur dioxide. It is insoluble in water, fat, dilute acid, inorganic acid and alkali, and only soluble in hydrogen. Fluoric acid. But under the action of light, titanium dioxide can undergo continuous oxidation-reduction reactions and has photochemical activity. This kind of photochemical activity is particularly obvious under ultraviolet irradiation. This property makes titanium dioxide a photosensitive oxidation catalyst for some inorganic compounds and a photosensitive reduction catalyst for some organic compounds.

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

Titanium dioxide (or titanium dioxide) is widely used in various structural surface coatings, paper coatings and fillers, plastics and elastomers, and other uses include ceramics, glass, catalysts, coating fabrics, printing inks, roof tiles and fluxes. According to statistics, the global demand for titanium dioxide in 2006 reached 4.6 million tons, of which the coatings industry accounted for 58%, the plastics industry accounted for 23%, papermaking 10%, and other 9%. Titanium dioxide can be made from ilmenite, rutile, or titanium slag. There are two kinds of titanium dioxide production processes: sulfate process and chloride process. The technology of the sulfate method is simpler than that of the chloride method, and it can produce low-level and cheaper minerals. Today, about 47% of the world's production capacity uses the sulfate process and 53% of the production capacity is the chloride process.

Ruico provide high quality rutile grade Titanium Dioxide for your production all the time.

Shawn

Regional Sales Manager

Zhejiang Ruico Advanced Materials Co., Ltd. (Stock No.873233)

Add: No.188, Liangshan Road, Linghu Town, Nanxun District, Huzhou City, Zhejiang Province, China 313018

Phone: +86 (572) 2903236

Fax: +86 (572) 2905222

WhatsApp: +86 15968208672

Cellphone: +86 15968208672

Website:www.ruicoglobal.com

E-mail: [email protected]