Pulp Technology

Recovery Technologies

We provide process technology, equipment (plants and components) and services for sulfite recovery.

Process technology

We have developed and continuously improved the Lenzing Mg base recovery process.


  • Efficient absorption system
  • Minimized chemical losses
  • Reduced sulfur emissions
  • Reduced operating cost

Range of services (complete solutions and components)

  • Recovery systems
  • Liquor incineration
  • Multistage absorption systems
  • Cooking liquor preparation
  • Treatment of odorous gases

This system facilitates the elimination of environmental impacts and provides a significant reduction of production costs brought about by high absorption efficiency and the integration of diffuse emissions.

The Lenzing Mg base recovery system was developed and optimized for minimized chemical losses and for efficient non-process-elements management.

The complete recovery system covers the incineration of the concentrated spent sulfite liquor together with odorous gases, the separation of the fly ash by a wet separator or electrostatic precipitator, the preparation of MgO-hydrate-slurry, which is used in multistage venturi washers to reduce the SO2 emission at the stack and gain raw acid. Then the raw acid is clarified and fortified in absorption towers and/or accumulators at different pressure levels.

Lenzing Technik has developed a special computer simulation using all relevant data form the DCS system to ensure a constant quality of the raw acid, compliance of emission and minimization of make-up MgO.


  • Optimized cooking liquor composition
  • Reduced chemical losses
  • Production of recycled SO2

In detail

Acid sulfite cooking requires the addition of free SO2 into the cooking liquor. This causes an unbalanced ratio of MgO to SO2.

MgSO3 => MgO + SO2

This process step - the thermal decomposition of magnesium sulfite - provides the means for direct SO2-recycling and reduces the costs of make-up chemicals and the level of emissions.


  • Complete sulfite recovery plants and components.


Consultation, engineering and project services in all areas of the pulp industry and related industries.

  • Feasibility studies
  • Consultation services
  • Process engineering
  • Basic- und Detai
  • Basic and detail engineering
  • Project management
  • Construction supervision
  • Start-up assistance and commissioning
  • After-sales service
  • Training


Lenzing Technik GmbH
Werkstraße 2
4860 Lenzing

Phone: +43 (0) 7672 701-0
Fax: +43 (0) 7672 968-58