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Applications
Mechanical Pulp Bleaching Kraft EOP De-Inking Oxygen
Delignification
Recommended products:
Sodium Silicate;
Magnabrite Magnesium Sulfate
Solutions
How it works: Sodium silicate is a key additive in
mechanical pulp bleaching processes. Silicates
stabilize bleaching liquors by complexing transition metals that catalyze
hydrogen peroxide decomposition and by buffering the pH to eliminate alkali
darkening. Optimizing silicate addition levels will increase pulp brightness and
reduce bleaching costs. Sodium silicates perform in a similar manner when used
in Kraft EOP stages.
Sodium silicate is also an important component in de-inking
recycled paper. Silicates enhance ink removal and dispersion from paper
fibers during pulping and flotation stages. They also act to stabilize hydrogen
peroxide when it is added to improve brightness.
Magnesium sulfate protects pulp fibers from oxidative degradation during
Kraft oxygen delignification stages. The addition of small
quantities of magnesium allows removal of more lignin without loss of pulp
strength. This process modification reduces chemical costs in later bleaching
stages.
For more information see Pulp and Paper applications.
Recommended literature:
De-inking Bulletin
Sodium Silicate in Peroxide Brightening of Mechanical Pulp
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