Fractionation of softwood TMP

The objective of this study is to determine whether softwood thermomechanical wood pulp (TMP) can be fractionated on the basis of fibre length and fibre coarseness using a rotating cone fractiontor, a continuous flotation cell and an air sparged hydrocyclone.;The rotating cone fractionator was found capable of fractionating softwood TMP fibres according to fibre length and fibre coarseness. A rough cone surface and a lower feed consistency improved fractionation performance. The continuous flotation cell was proved to be successful for fractionating softwood TMP fibres according to fibre length and fibre coarseness. A lower feed consistency and a lower feed flow rate improved fractionation performance. The air sparged hydrocyclone was found capable of separating about 5 wt% of long fibres from feed softwood TMP fibre suspension. A lower feed consistency and a higher air flow rate improved fractionation performance.;Based on the fractionation performance comparison, the continuous flotation cell was found to give the best fractionation performance for either removing fines or recovering long fibres from the feed softwood TMP fibre suspension at feed consistency of 0.15 wt%.