Ash Crystallization Supports Emissions Reduction at Pulp Mill

Valmet and Mercer Stendal are collaborating on the installation of an ash crystallization plant at the pulp mill in Arneburg, Germany. The project aims to improve chemical circulation, reduce non-process element accumulation and increase recovery boiler availability through longer maintenance intervals.

Removal of chloride and potassium reduces boiler corrosion risks
The ash crystallization plant will recover sodium salts while removing non-process elements, primarily chloride and potassium, from the mill’s liquor cycle. Accumulation of these compounds contributes to plugging and corrosion in recovery boilers, increasing maintenance requirements and affecting operational stability.

By reducing concentrations of these elements, the system is expected to extend intervals between recovery boiler maintenance shutdowns to 24 months or more. Longer operating cycles may improve equipment availability and reduce production interruptions.

Recovered chemicals support circularity in pulp production
The process is designed to improve chemical recirculation by lowering dependence on make-up chemicals used in pulp production. The removal of non-process elements through ash crystallization also eliminates the need for ash dumping, which can reduce wastewater generation and associated emissions.

These mechanisms contribute to improved resource efficiency through increased reuse of process chemicals rather than replacement with externally sourced inputs.

Existing mill infrastructure will incorporate the new system
The installation demonstrates application of ash crystallization technology in an existing mill environment rather than only new facilities. Mercer Stendal, operating since 2004, has implemented multiple investments focused on performance and sustainability improvements.

Valmet will supply the ash crystallization system and related engineering expertise, while Mercer Stendal will integrate the solution into mill operations as part of its long-term environmental and operational targets.

The order was included in Valmet’s first-quarter 2026 orders received. Financial details were not disclosed. Startup of the crystallization plant is scheduled for the fourth quarter of 2027.

“Since the mill started up in 2004, we have systematically invested in improving its performance and sustainability. Our sustainability efforts are guided by the Mercer vision and values and our long-standing philosophy of responsible business practices that encompass sustainability, safety, financial responsibility, and strong leadership. The new ash crystallization plant will help us to further improve both operational and environmental performance. We chose Valmet to deliver this project based on both their technical expertise and our previous joint projects,” says Dr. Martin Zenker, Mill Manager, Mercer Stendal.

Edited by Natania Lyngdoh, Induportals editor, assisted by AI.

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