Using hydrocyclone fractionation to improve chemical pulp quality

• Main Authors: Marvin Potgieter, W. Jimmy Pauck, Jonas Johakimu, B. Bruce Sithole
• Format: Article
• Language: English
• Published: Elsevier 2021-04-01
• Series: South African Journal of Chemical Engineering
• Subjects: Fractionation efficiency; Mass reject rate; Consistency; Hydrocyclone; Pulp fractionation; Wood resin
• Online Access: http://www.sciencedirect.com/science/article/pii/S1026918521000032

Production of chemical pulp is accompanied by various impurities in addition to the cellulose fibres produced. The impurities are mainly due to lignin fragments and wood resin components in the wood. The possibility of removing impurities such as fines and extractives at the early production stages by hydrocyclone fractionation was investigated.A sample of unbleached eucalyptus chemical pulp was fractionated using a hydrocyclone at feed consistencies of 0.1% to 1.0% and mass reject rates of 5% to 41%. Fractionation efficiency was assessed by measuring changes in consistency, Canadian Standard Freeness, fibre morphology, and extractives (wood resin) in the fibres.It was found that fractionating at consistencies of 0.6 - 1.0% at mass reject rates of 5 – 20% produced acceptable fractionation, with simultaneous removal of extractives associated with fibre fines.Fractionation of unbleached chemical pulps under these conditions could produce chemical pulps with enhanced bleaching and further processing properties.