Ecological solutions for recovery of secondary materials from post-consumer fiberboards: Characterisation of generated fines and fibres from impact reactor and TMP refining.

The characterization of recycled fibers is crucial to understand the suitability of such techniques for medium-density fiberboard (MDF), especially in newly developed recycling processes. Damage to the fibers can result from inefficient recycling of waste fiberboard. It may affect the presence of residual resin, formaldehyde/nitrogen content, pH, and excessively short lengths, which can influence the overall performance of the MDF. This research examines the properties of residual and post-consumer wastes recycled using thermomechanical pulping (TMP) and an impact reactor (a wet process). Utilising the Dynamic Image Analysis tool (QICPIC), an analysis of fiber length reveals that recycling procedures significantly influenced the fiber length compared to virgin fibers. Besides, there was a significant increase in pH (5.2–5.7) and nitrogen (3.4–4.9%) in the recycled wood fibers. The combined findings of nitrogen content, pH, and spectroscopy indicate the presence of some residual resin elements in the recycled substrates, even though scanning images did not clearly show any signs of residual resin. Considering a substitution rate of 15 to 25% of recycled fibers with virgin fibers for MDF, the impact of the observed outcomes on the performance of the MDF remains to be determined.