Valmet will supply a new ash crystallization plant to Mercer’s Stendal pulp mill in Arneburg, Germany, supporting the mill’s long-term goals for lower emissions, improved chemical recovery and stronger operational performance.

The plant is scheduled to start up in Q4 2027.

Why the Investment Matters

Mercer Stendal produces around 740,000 tonnes per year of bleached softwood kraft pulp. The new crystallization system will help close the mill’s chemical circulation by recovering valuable sodium salts and removing non-process elements such as chloride and potassium.

This is important because chloride and potassium can cause:

• recovery boiler plugging
• corrosion
• shorter maintenance intervals
• reduced boiler availability

Operational and Environmental Benefits

Valmet says the ash crystallizer will help Mercer Stendal:

• reduce make-up chemical demand
• eliminate ash dumping
• reduce wastewater
• lower related emissions
• improve resource efficiency
• extend recovery boiler maintenance intervals to 24 months and beyond

The plant will be able to process 140 tonnes of ash per day.

Circularity in Existing Pulp Mills

The project also shows how ash crystallization technology can support existing pulp mills, not only new large-scale greenfield projects.

For kraft pulp producers, improving the liquor cycle is becoming increasingly important as mills seek better efficiency, lower emissions and longer equipment availability.

Industry Insight

Ash crystallization is a practical example of circular mill technology. Instead of treating ash as waste, the system recovers useful chemicals and removes harmful elements from the process loop.

For pulp mills facing cost pressure and stricter sustainability targets, this type of investment can improve both environmental performance and long-term production reliability.

Last Updated on 20/05/2026 by Jota Machinery