Pulp and Paper

PQ's liquid sodium silicate and magnesium sulfate products are uniquely suited to perform several critically important functions in a wide variety of pulp brightening, delignification and waste paper deinking processes. Used separately or in combination these products deliver consistently high quality pulp and paper products at the lowest possible cost. 
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 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.
Mechanical Pulp Bleaching

Kraft EOP


Oxygen Delignification

Raw Water Treatment

Peroxide Bleaching of Pulp


White Water Treatment
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