This year, the Kemi bioproduct mill achieved a significant quality milestone when the strength potential of softwood pulp reached a level that makes it highly competitive even in the most demanding end-use applications. "The strength of softwood pulp from the Kemi bioproduct mill is now on par with the best long-fiber pulps, which is a significant achievement for such a young mill," says Tom Nickull, VP Sales Services at Metsä Fibre.
Strength enables cost savings
From the customer's perspective, the strength is one of the most important pulp properties. "The stronger the pulp, the less is needed in the customer's process. This reduces the customer's fiber costs, which can be a significant part of the total product cost," says Nickull. For example, in the production of tissue papers, raw material costs can account for over 80% of the total costs. Therefore, even a small improvement in strength is clearly reflected in the total cost. "The brightness and cleanliness of high-quality pulp are usually in order, so strength is the property that distinguishes high-quality pulps from each other," Nickull says.
Northern softwood is the best raw material for paper
The wood raw material of Kemi bioproduct mill is Nordic softwood, whose unique fiber properties support the high strength of the pulp. The fibers of the wood are thin-walled but still durable – they are easy to refine and highly modifiable. "Northern softwood is simply the best raw material for long-fiber pulp and papermaking," says Juho Rossi, Technical Customer Service Manager at Metsä Fibre.
Continuous optimization behind quality
The improved strength properties of the Kemi pulp are not due to a single technical change but systematic daily process optimization. "Recently, for example, we have fine-tuned the conditions of the digester," says Marja Aalto, Production Engineer of the fiber line at the Kemi bioproduct mill. Other key quality properties, such as cleanliness, brightness, and bale and unit quality consistency, have been at a high level since the mill started up.
Usability and quality go hand in hand
The pulp production at Kemi bioproduct mill was started in September 2023. After the ramp-up, the focus has increasingly shifted to continuous quality improvement. "When the usability of a new mill is brought to a good level and production is stable, it is easier to fine-tune the process to a top level. This is the goal of our entire staff – we know that pulp is always made for the customer," says Aalto. "Consistent pulp bales and units ensure that the product always behaves the same way in the customer's process. This allows customers to optimize their own processes without the risk of overdosing or quality variation," Nickull continues.
Customer feedback and quality monitoring guide development work
Metsä Fibre's technical customer service works in close collaboration with production, and feedback from customers directly guides development work at the mills. "Our quality management consistently receives praise in customer feedback. From the customer's perspective, this is our greatest strength," says Nickull.
The quality of the pulp is continuously measured. In addition to real-time online measurements, pulp samples are regularly taken and tested both in the mill's own and external laboratories. Laboratory refining tests are regularly conducted with an industrial refiner. These tests particularly monitor the refinability and strength property development of the pulp, such as tensile strength. "This way, we can see how strength develops at different pulp refining levels," describes Rossi.
Environmental performance to a new level
An important part of quality is also a responsible, environmentally efficient production process. The Kemi bioproduct mill has raised the environmental efficiency to a completely new level. The mill's environmental impact is significantly lower than that of the old mill, even though production volume has increased significantly. This is because the mill does not use any fossil fuels and utilises the Best Available Technology (BAT) defined by the EU or even more advanced technology (BAT+), which includes closed cooling water circulation, cooling towers, a wastewater treatment plant, and a sulfuric acid plant.
The mill's water consumption and emissions to water and air are also significantly lower than before and clearly below the environmental permit limits. Additionally, the mill is 250% self-sufficient in electricity, meaning it produces more electricity than it consumes.
"Our customers are increasingly monitoring the environmental impact of their supply chains. By reducing our own carbon footprint, we help our customers reduce theirs, and this is a significant competitive advantage for them," concludes Nickull.