Fibre customer magazine 2025

Read more about oxidised lignin.

New lignin product makes concrete more flexible

Metsä Fibre is developing a new lignin product at its Äänekoski demo plant. The new lignin product, produced from lignin separated from the pulp process, can replace the fossil-based chemicals used in concrete production. The product is also being considered for other uses.

Text: Maria Latokartano Photos: Metsä Fibre

The mill ecosystem in Äänekoski is expanding with the construction of Metsä Fibre’s lignin refinery demo plant in connection with its bioproduct mill. Technology company ANDRITZ is delivering equipment for the demo plant and Dow, a global company active in the chemical industry, is also involved in the project. Construction has already started in the Äänekoski mill area, and the plant is planned to be ready for test use in 2025. The plant will produce two tonnes of the new kind of lignin product per day.

interested in it because the market has a clear need to find sustainable solutions to replace fossil raw materials,” says Anna Suurnäkki , VP, Research at Metsä Fibre. In pulp production, lignin is separated from the fibres into black liquor in the chemical cycle and used as a bioenergy source. The demo plant’s modified lignin could be used as, for example, a bio-dispersant plasticiser in concrete and gypsum applications. Concrete plasticisers are additives that improve the technical features of concrete, such as its pumpability.

New lignin product could function as a bio-dispersant plasticiser

Product can be utilised in liquid or dried form

Along with pulp, lignin is one of the most common biopolymers in nature. Approximately one quarter of the softwood and hardwood chips used by Metsä Fibre’s pulp and bioproduct mills is lignin. The pulp process at the Äänekoski bioproduct mill produces approximately 1,800 tonnes of lignin per day. This makes it a significant side stream from the perspective of bioproduct modification. “Lignin has always been an interesting material from a research perspective. Right now, we are particularly

The demo plant will refine the lignin using the LigniOx process, which uses black liquor from the bioproduct mill’s evaporation plant as raw material. The black liquor is fed to the demo plant along a pipeline. In the LigniOx process, lignin is precipitated from black liquor using carbon dioxide, after which it is further processed with alkali and oxygen. The end product is finalised during post-treatment. The new lignin product is a liquid that can be utilised as such or dried.

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