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ANDRITZ oxygen delignification – minimal environmental impact and low chemical consumption

Through advanced mixing technology, innovations in process control, and intelligent reactor designs, ANDRITZ delivers oxygen delignification systems with superior levels of kappa reduction and minimal effect on chemical pulp quality.

The challenge

It can be challenging to produce good quality chemical pulp while trying to reduce the mill’s impact on the environment. It becomes even more complex to comply with environmental requirements while maintaining high throughput and runability in a cost-effective way.

The solution

ANDRITZ technology helps to reduce a mill’s COD, BOD, and AOX impact in an advanced process. Lignin is removed from the pulp by oxygen delignification in one or two reactors, depending on process requirements. After this, the pulp is washed before bleaching. This substantially reduces the consumption of chemicals and the amount of dissolved organic material in the bleach plant. By performing oxygen delignification prior to screening, a considerable fraction of shives is converted into good pulp, resulting in higher yield and better runability of screen room.

Processes and technologies available from ANDRITZ

  • Pressurized oxygen delignification reactors (one or two stages depending on requirements)
  • AMix chemical mixer – efficient mixing of oxygen into pulp
  • Fluidizing blow tube design – less volume, smaller footprint, smooth operations
  • Drum Displacer (DD) washer – displacement washer for post-oxygen washing
Oxygen delignification system

Two-stage oxygen delignification system at Veracel Celulose S.A. mill, Brazil


ANDRITZ Oy, Finland

Phone: +358 (0)20 450 5462

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