TITANIUM DI OXIDE (TiO2):
Titanium
dioxide is also known as rutile, flamenco, titanium oxide and also dioxo
titanium.
Chemical formula: TiO2
Properties:
- White inorganic substance
- Non toxic
- It absorbs uv rays and ability to scatter the light.
- Chemically inert
Occurrence:
Titanium dioxide is separated from the mineral ores like rutile and ilmenite.it is prepared by using sulphate and chloride process.
PREPARATION:
Sulphate process:
The ore
ilemenite is treated with sulphuric acid. it gives the mixture of sulphates. The
crystals of ferrous sulphate are eliminated in the crystallization process by
adding the nucleating agents to the gas stream. All iron is removing from the
solution so the colour of the final product is not spoiled. The titanyl
sulphate mixture is hydrolysed in solution to give the insoluble hydrated
titanium dioxide. This product is heated to get the pure titanium dioxide. The
remaining sulphuric acid is decomposed in the solid and the water is evaporated
in the calciner. These solid crystals are coated with another substance such as
aluminium oxide to give the fine soluble titanium oxide liquid.
Chloride process:
In this
chloride process, titanium dioxide is obtaining by two methods:
Method I:
The dry
ore is mixed with coke and chlorine in the chlorinator to prepare the titanium
chloride. The container is preheated because the reaction with chlorine maintained
by the sufficient temperature and the liquid titanium chloride is used to control
the temperature.
Method II:
The titanium
chloride is reacted with oxygen and another carbon monoxide substance during
the process of oxidation. By adding the seed crystals, the titanium oxide is formed
as a solid. This titanium dioxide is solid is filtered out of the waste gases. The
pure titanium dioxide is obtained by washed and dried before the surface
treatment.
