ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Displacement washing of pulp with urea solutions

F. Potůček and M. Pulcer

Department of Wood, Pulp, and Paper, Faculty of Chemical Technology, University of Pardubice, CZ-532 10 Pardubice, Czech Republic

E-mail: Frantisek.Potucek@upce.cz

Received: 3 March 2006  Revised: 11 April 2006  Accepted: 15 April 2006

Abstract: Two basic mechanisms of displacement washing of pulp fibres were investigated. Experiments were carried out in a laboratory washing cell that simulated a single stage of displacement washing. The step-change method has been employed in investigation of alkali lignin profile in outlet stream of washing effluents. The addition of urea to wash water resulted in a decrease of the liquid layer immobilized on the fibre surface. It had a positive effect on the washing efficiency expressed in terms of the void local efficiency.

Keywords: pulp - washing - mechanism - modelling - urea

Full paper is available at www.springerlink.com.

DOI: 10.2478/s11696-006-0066-0

Chemical Papers 60 (5) 365–370 (2006)