Water Based Coatings That Keep a Pack inside the Fibre Stream
Water-based dispersion coatings achieve food barrier requirements while maintaining full fiber repulpability and standard mill recovery yields.
Fine Screen Rejects
Definitional Material
Non-conforming materials are removed from the pulp stream during the final stages of cleaning before the paper machine. These fine screen rejects typically consist of small plastic fragments, stickies, shives and tiny pieces of metal that passed through earlier cleaning steps. Efficient removal is necessary for preventing defects in the final paper sheet and protecting downstream equipment.
Screening Mechanism
The separation occurs based on size or shape as the pulp passes through slots or holes that are often smaller than 0.15 millimetres. These fine screen rejects are concentrated in a separate stream and sent for further treatment or disposal.
Operational Impact
A high volume of contaminants in this stage suggests that the initial pulping or primary screening was insufficient. Because fine screen rejects often contain a proportion of usable fibre trapped with the waste, many mills use a secondary screen to recover as much good material as possible. Managing this waste stream effectively reduces the overall fibre loss and improves the economic efficiency of the recycling process.
If these particles are not removed, they cause breaks on the paper machine or create spots that degrade the print quality of the finished board. Consistent monitoring of the reject rate helps operators optimize the settings of the screening system.