Effects of carbonization on the physical properties and combustion behavior of fiberboard sanding dust pellets

In this study, sanding dust pellets were prepared using a flat-die extrusion molding machine and then carbonized at temperatures ranging from 300 to 600 °C. The density and mechanical compression resistance of pellets carbonized at 400 °C decreased by about 30% and 80%, respectively. Carbonization led to a homogeneous structure in the pellets, with a slight change in the surface area. When the carbonization temperature was increased to 600 °C, the composition and higher heating value (27,732 kJ/kg) of pellets approached the anthracite level. Additionally, 40%–80% of nitrogen in pellets could be removed through carbonization. Thermogravimetric studies indicated that the combustion end temperatures of pelletized samples were delayed at about 500 °C, compared with those of powdered samples. The only main peak of the derivative thermogravimetric analysis for carbonized pellets combustion indicated that the combustion was relatively slow and stable. Kinetic analyses revealed that the apparent activation energy (E) increased during the later combustion stages of the carbonized pellets with increasing carbonization temperature. However, pellets carbonized at 300 °C had the highest E (186,358 J mol−1) in the initial combustion stage, compared with those of other pellets (50,000 to 114,507 J mol−1).