Table of Contents
Physical Separation in Science and Engineering
Volume 2007 (2007), Article ID 91740, 6 pages
Research Article

Experimental Results for the Settling Behaviour of Particle-Fiber Mixtures

1Institut für Mechanische Verfahrenstechnik und Mechanik (MVM), Universität Karlsruhe (TH), 76131, Karlsruhe, Germany
2Fachgebiet Papierfabrikation und Mechanische Verfahrenstechnik (PMV), Technische Universität Darmstadt, 64283, Darmstadt, Germany

Received 1 October 2007; Accepted 6 December 2007

Academic Editor: Eiji Iritani

Copyright © 2007 Markus Feist et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Sedimentation of organic fibres and inorganic particles can be observed in several industrial applications. Fibres are involved not only in wastewater treatment but also in other separation applications. In the paper industry, the separation of inorganic filler and coating particles from short cellulose fibres is still a challenge in the recycling process. During that process, particles have to be removed to obtain a purified fibre suspension. These fibres can be used again to produce new paper. With the currently applied techniques, like screening and flotation, the efficiency of short fibre separation is very poor. Moreover, also separation by sedimentation fails due to similar settling velocities of heavy-small particles and the light and larger fibres. This paper concentrates on the sedimentation of organic fibres and inorganic particles in water. The investigated suspensions are made by resolving two different and specially produced papers a coated and an uncoated one, as well as the single components used for its production. We observe a different sedimentation behaviour according to the concentration of fibres and particles in the suspension and the pH-value of it. The main result is that, according to the fibre rate, the sedimentation behaviour is particle dominant or fibre dominant.