Particle board production using paper mill waste sludge and European black pine (Pinus nigra A.) wood chips

Paper mills use excessive amounts of water throughout production to produce paper. While mills treat water for reuse, sludge is generated and must be processed as a waste, along with some washing water. In this study, waste sludge from a kraft process mill mixed with up to 40% black pine (Pinus nigra) wood chips was investigated for multi-purpose board production using urea formaldehyde resin and ammonium chloride as a hardener. The panels were pressed at 150 degrees C for 7 minutes between 2.4 MPa and 2.6 MPa. The resulting panels were 18 mm thick, with a density of from 0.69 gr/cm3 to 0.71 g/cm3. Measurements of density, moisture, water absorption, thickness swelling, modulus of rupture, modulus of elasticity and internal bond strength to the surface were carried out on the particle board panels. The results indicated that panels could be used for general purposes.