2. Introduction
● History of Tio2?
● Ilmenite ore + Sulphuric
acid
● Hydrolysis
● Calcium sulphate
● Tio2 in anatase
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3. Synthesis of Tio2 pigments
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1: Sulphate route
(hydrolysis of aqeuous Solution)
2: Chloride route
(Vapour phase oxidation of TiCl4)
4. Sulphate process
• Dissolution of suitable ore (ilmenite ore)
• Insoluble impurities removed out
• Hydrolysis at boling point
• Precpitate titanium hydrate is washed
and leached
• Tio2 pigments produces.
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5. 5
• Drying and grinding
• Digestion
• Reduction
• Clarification
• Crystallization
• Filteration
• Washing and leaching
• Calcination
• Milling
Steps involved in
extracting TiO2 pigments
6. “
”
Chloride process
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• Steps involved :
1. Chlorination :
Dry titanium and dry coke
Chlorine at 900 C
TiCl4, CO, CO2
2. Purification:
TiCl4 is condensed
Removal of impurities
3. Oxidation:
TiCl4 is vapourird and burnt
Modifying agent
Pigmentary TiO2 + Chlorine
7. “
”
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Properties:
Opacity:Opacity of a material Is an indicator of how much light passes through the
material, TiO2 efficiently scatter visible light. Theory based on R.I ration says that if
difference of R.I between particle and medium is high then greater amount light
reflected from surface. This is how opacity is achieved in paint film by using
Titanium pigments.
Durability: It is the degree to which paints and paint material with stand with
distructive effect of addition to which they are subjected.
Most polymer are attacked by uv radiation and sun rays
2 factor which affect durability of paints are:
Chem and phy nature of paint films
Environment that paint fllm has to withstand.
Rutile TiO2 pigment is good uv absorber .
8. Properties:
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Gloss development :
Film with least defect at its surface and one with the most ability to form a glass like
surface will be have highest gloss
To mimize surface imperfections TiO2 pigments manufacturers will have grades of
pigment which will easily dispersed.
Storage ability:
Titanium pigment is not normally the culprit in can instability; but the incorrect choice of
pigment can cause instability, such as bodying or syneresis or flocculation. Again, the
inorganic coatings on the titanium pigment do help to overcome instability in the can, and
it is not normal these days to use an uncoated, unrefined grade of titanium pigment in
premium quality paints.
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● Plastics Industry
● Unlike the surface coatings industry, which uses relatively thin films, the plastics
industry uses relatively thick profiles. The pigment loadings tend to be lower
than in paint products; this is a generalization because thermoplastic polymers
such as ABS, which has a pronounced yellow undertone, require relatively high
pigmentation to mask this polymer colour.
● The titanium pigment requirement for thermoplastic products is easy dispersion
under low shear conditions. This is assisted by use of titanium pigments, which
are hydrophobie in na
Applications:
10. Application:
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Rubber Industry :
Applications in rubber are of relatively small volume and the dispersion equipment is of a very high
shear nature, that is internal mixers, and here the titanium pigment used is an uncoated anatase or
rutile. Anatase is used where chalking is required, and rutile where non-chal.king is required.
Paper Industry :
Historically, anatase has been used for paper production. However, a shift to rutile was made in
Australia a number ofyears ago, and considerable reduction in titanium pigment usage was made by
this change. The two large areas ofrutile pigment usage in the paper industry are:
(a) beater addition to wood pulp; and
(b) board coating.
11. Recent developments of Tio2 pigments
Availability of well proven well optimized Tio2 production technolgies such
as Sulphate process, Chloride process, but as well as Prospect of new
technology commercialization such as Hydrochloride extraction process.
Since Tio2 pigments have very high R.I among known transparent material
Whiteness is also almost 100% , low color tone, wide range of raw material in
nature, relative cheapers.
So the alternatives to replace TiO2 as white pigments are not
possible for next few decades
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