Barium sulphate
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Barium sulphate
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Color Index
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Pigment White 21,22
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Formula
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BaSO4
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Structure
Barium sulphate is available in a natural form (baryte) and in a synthetic form
(precipitated baryum sulfate = blanc fixe). The natural form of barium sulphate
exists as the mineral "heavy spar". It is crushed, washed, dried then
usually micronized in order to enhance its dispersibilty (particle size is reduced
from 25 µm to 2-10µm). The synthetic form has a finer texture than the
natural grades, giving it a higher oil absorbtion. It is manufactured by reacting
barium compounds with sulphuric acid or soluble sulphate salts.
Properties
Barium sulphate is very inert and insoluble.
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Properties of barium sulphate
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Property
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Baryte
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Blanc fixe
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Refractive Index
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1.64
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1.64
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Density
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4.5
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4.4
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pH
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7-8
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6.5-7.5
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Oil Absorption
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9-13
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13-17
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Chemical Stability
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very good
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Heat Stability
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good
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Light fastness & Weatherability
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good
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Uses
Natural barium sulphate is used in anti-corrosion paints, industrial paints and coatings
for building and construction. Synthetic barium sulphate is used in primers,
undercoats, and industrial finishes.
