A-Recovery+ chemical recovery concept

allows mills to see the chemical cycle in a new light

Over the years, chemical recovery technology suppliers have worked with pulp mills to “close” the chemical recovery loops in order to reduce emissions and effluent – and also to increase recovery efficiency. These loop closures have sometimes led to a build-up of certain chemicals and the creation of side streams that are either ignored or disposed of.

A major target of ANDRITZ’s recent development work has been to innovate solutions for utilizing the side streams of a kraft pulp mill to unleash the hidden potential for generating profit, as what was once considered “waste” can be converted to valuable raw materials for commercial-grade bioproducts.

The objective continues to be operating chemical recovery systems as efficiently and environmentally sound as possible while minimizing capital investment and maximizing profits.

Current state of chemical recovery: Multiple opportunities to improve resource efficiency of a pulp mill by better utilization of side streams.


ANDRITZ was inspired to take a fresh look at achieving this by shining a new light on the chemical cycle, with two targets in mind: 1) for environmental reasons, further closing of the chemical cycle, and 2) for business reasons, converting the side streams into something of value that could be used by the mill in place of purchased chemicals and energy, or sold for additional revenue. Today, with the increased knowledge and emphasis on biorefineries and bioproducts, this potentially presents a new source of profits.

This development work resulted in a technical solution called A-Recovery+, a modular chemical recovery concept that optimizes the sodium/sulfur (Na/S) balance in a mill to increase the revenue generated and/or to reduce costs significantly. A-Recovery+ also sets the stage for pulp mills to implement a fossil-free operation.

This two-pronged approach of A-Recovery+ – environmental soundness and commercial benefit – will please mills’ process and production experts, and accountants as well. The first modules developed inside the A-Recovery+ concept generate economic value from the side streams in a traditional kraft pulp mill by adding value such as:

  • Purifying raw methanol to commercial quality biomethanol
  • Producing commercial quality concentrated sulfuric acid on-site
  • Recovering high-quality lignin from black liquor

Development work continues to identify and unleash all the hidden potential in the side streams created during the kraft mill recovery process.

These interesting and attractive options for next-generation chemical recovery will reduce effluents and water consumption, reduce the need for make-up chemicals, and convert side streams into valuable bioproducts.

The first three modules of A-Recovery+ chemical recovery concept generate profits by valorization of raw methanol, CNCG, and lignin side streams.



ANDRITZ received an order from Södra, Sweden, to supply a biomethanol purification plant for the Mönsterås pulp mill. When completed, the plant will annually produce 5,000 tons of biomethanol from renewable raw materials. The biomethanol will be in compliance with IMPCA methanol quality reference specifications for merchantable methanol.

EU’s target is to have 10% of the transport fuel coming from renewable sources, such as biofuels, by 2020. Södra has announced its own strategy to be totally fossil-free by 2030.


“Methanol has many worthwhile commercial applications – including being used for making special chemicals – which brings added value to Södra, at the same time as fitting in with its sustainability goals.”


Senior Project Manager, Södra Innovation & New Business