In nature, Titanium dioxide occurs in three different crystal modifications: anatase, brookite and rutile. For the manufacturing of pigments, however, only the rutile and anatase modifications are of importance. Although they belong to the same crystal system, there are characteristic differences in the lattice structure. The lattice cells are closer packed in rutile than in anatase. For this reason, rutile has a higher thermal stability than anatase. While the cells of anatase are linked at four edges, rutile is just linked at two edges. The main differences of the two pigment types concerning the physical properties and characteristics as a pigment are based on this fact.
Raw materials: Ilmenite or titanium slag, among others, are used as raw materials for the manufacturing of titanium dioxide using the sulphate process. For the production using the chloride process, however, natural or synthetic rutiles are used.
Manufacturing process: Nowadays, titanium dioxide is worldwide manufactured according to two methods. On the one hand, the sulphate process is used, enabling the production of anatase or rutile, or the chloride process which is only possible for manufacturing rutile.
Titanium dioxide production using the sulphate process
In the sulphate process so-called sulphate pigments (anatase or rutile) are manufactured from ilmenite ore (FeTiO3) and concentrated sulphuric acid. Most manufactures meanwhile make complete use of the by-products (diluted hydrochloric acid, green vitriol) resulting from the process.
Titanium dioxide production using the chloride process
The chloride process, that was developed later, uses an environmentally-friendly technology with a reaction of a titanium enriched raw material caused by chlorine gas and petrol coke. At temperatures of around 1000°C titanium tetrachloride (TiCI4) is produced which is purified by distilling and re-oxidized to titanium dioxide in a pure oxygen flame. The occurring chlorine is returned to the process. In this process the chloride pigments are produced (however only rutile pigments).
The properties of the product are optimized by organic and inorganic treatments.
Scholz, as an authorised distributor of PRECHEZA and Kronos, is responsible for Germany and offers the complete portfolio of Titanium dioxide pigments.
|Anatase pigments||Sulphate process||Chloride process|
|Anatase pigments used for Food/ Cosmetics|
|Anatase pigments for Pharma|
|Rutile pigments primarily used for coatings|
|Rutile pigments primarily used for plastics|
|Rutile pigments primarily used for glass, enamel and ceramic products|
|Titanium dioxide without pigment properties|
|Titanium dioxide photocatalysts|
TFor types not included in this list please feel free to contact our sales department. By e-mail to email@example.com.
For further technical information as well as data sheets please contact our product safety department firstname.lastname@example.org or visit the website of Kronos http://www.kronostio2.com/en/technical-services.
Apart from the trading products of Kronos, Scholz also offers liquid preparations on the basis of titanium dioxide.