Valmet's Ash Crystallizer helps Mercer Stendal pulp mill in Germany to reduce emissions and improve performance

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19 May, 2026, 08:27 GMT

Valmet Oyj's press release on May 19, 2026, at 11:00 a.m. EEST

ESPOO, Finland, May 19, 2026 /PRNewswire/ -- Valmet will deliver a new ash crystallization plant for Mercer Stendal mill in Arneburg, Germany. This investment is part of Mercer's long-term vision to further reduce the mill's emissions and improve its performance. Ash crystallization plant contributes to this target by helping to close the mill's chemical circulation, reducing the need for make-up chemicals, and by helping to extend the recovery boiler maintenance intervals to 24 months and beyond.

"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.

The ash crystallization plant will recover valuable sodium salts and remove non-process elements, primarily chloride and potassium, from the mill's liquor cycle. This reduces plugging and corrosion in the mill's recovery boiler which enables longer intervals between maintenance shutdowns, increasing recovery boiler's long-term availability. Removing these non-process elements with Valmet's Ash Crystallizer design eliminates the need for ash dumping, which in turn reduces wastewater and lowers costs through decreased make-up chemical demand. This solution delivers clear environmental benefits by reducing associated emissions.

"We are committed to advancing circularity and resource efficiency. Delivering a new ash crystallization solution to an existing mill is very much in line with these targets and brings several operational and environmental benefits. This project showcases that the ash crystallization solution is not only suitable for new large mills but also brings significant benefits to existing mills. We truly value our cooperation with Mercer and the Stendal mill in finding long-term solutions to optimize the mill's performance," says Claus Jensen-Holm, Director, White Liquor and Evaporation, Pulp Mills at Valmet.

The order was included in Valmet's orders received in the first quarter of 2026. The value of the order will not be disclosed. The new crystallization plant is scheduled to be started up during the fourth quarter of 2027.

Mercer Stendal mill in Arneburg, Germany was started up in 2004 and today has a capacity of 740,000 tonnes per year of bleached softwood kraft pulp.

Technical information about the delivery

The Valmet Ash Crystallizer plant will have capacity to process 140 tonnes of ash per day. Valmet's delivery covers the complete plant with extensive delivery scope including electrical and instrumentation systems (E&I), steel structures, and erection. Valmet also delivers an expansion of the existing mill-wide Valmet DNA automation system. The new plant will be integrated into existing mill operations, mainly to the evaporation plant.

Information about the customer Mercer and Mercer Stendal

Mercer Stendal is part of North American Mercer International Group, a forest products company with operations in Germany, Canada, and the United States. In Stendal, Mercer operates one of Europe's most modern pulp mills and implements a biorefinery concept where wood is used extensively for pulp, bioenergy, and biochemicals, such as tall oil, turpentine, and methanol. Today, after several large optimization projects, Mercer Stendal's annual production capacity of kraft pulp is 740,000 tonnes. The biomass power plant at the site is one of the largest of its kind in Germany with an output of 148 megawatts. The mill produces enough green energy to meet its internal needs as well as provides green energy to the electricity grid.

VALMET

Corporate Communications

Further information:
Pontus Johansson, Product Sales Manager, White Liquor & Evaporation Technology, Pulp, Energy and Circularity, Valmet, tel. +46 76 639 7252

Bernhard Trunk, Product Sales Manager, Central Europe & UK, Pulp, Energy and Circularity, Valmet, tel. +49 173 308 0559

Valmet is a global technology leader in serving process industries. We work with our customers throughout the lifecycle, delivering cutting-edge technologies and services, as well as mission-critical automation and flow control solutions. Backed by more than 225 years of industrial experience and a global team of 18,500 professionals close to customers, we are uniquely positioned to transform industries toward a regenerative tomorrow.

In 2025, Valmet's net sales totaled approximately EUR 5.2 billion. Our head office is in Espoo, Finland, and we have experts in approximately 40 countries around the world. Valmet's shares are listed on Nasdaq Helsinki.