Barrier Paperboard Substrate Selection and Wet End Disintegration Yield Testing
Aqueous dispersion barrier boards outperform extruded polyolefins by delivering over 95 percent wet end fiber yield and avoiding heavy EPR penalties.
Coarse Reject Mass
Screen Efficiency
Heavy debris separation isolates large contaminants from recycled pulp suspensions before the refining stage. Mill operators monitor the coarse reject mass to evaluate the efficiency of screening systems. High levels of these rejects indicate a high volume of plastic film or metallic staples in the incoming wastepaper.
Process Control
Slurry flow rates through the primary screens are adjusted based on the dry weight of this material collected over a set operating window. If the screen basket wears down, the weight of the rejects drops as larger particles slip through to the accepted stock. Regular sampling prevents the contamination of the accepted stock and maintains the cleanliness of the final paper sheet.
Waste Management
High rejection rates require efficient dewatering presses to reduce transport costs and prepare the solid residue for disposal. The moisture content of the waste must be minimized before incineration to maintain thermal efficiency in the mill boiler. Modern recycling plants use automated screw presses to squeeze water out of the rejects until a high solids content is achieved.
This dewatered stream represents the non-recyclable portion of the raw material, and its reduction directly lowers the carbon footprint of the mill’s waste disposal system by minimizing transport volume.