Extraction Waste
Non-fibrous materials and unseparated paper flakes remain in the pulping vessel after the primary slurry has been discharged. The hydrapulper residue consists of plastics, adhesive tapes, wet-strength paper fragments, and metal foils that resist water disintegration. This reject material must be extracted continuously or in batches to prevent it from building up and blocking the pulper grates.
Quantifying this waste helps packaging engineers evaluate how much raw material is lost during the initial stages of recycling.
Composition Analysis
The sorting of waste streams at the pulper exit reveals the types of contaminants present in incoming packaging materials. Evaluating the hydrapulper residue involves drying and separating the captured materials to distinguish between recyclable paper flakes and non-recyclable polymer films. If the residue contains a high proportion of fiber flakes, it indicates that the pulping time or the chemical dose was insufficient.
On the other hand, a high proportion of plastic and metal laminates shows that the packaging has a complex structure that reduces the yield of usable fiber. This analysis guides improvements in packaging design and pulping recipes.
Disposal Management
High quantities of heavy rejects increase the operating costs of the recycling plant due to transport and disposal fees. Reducing this fraction is a priority for companies aiming to improve their environmental footprints.
