Patent ID: 6248207
Filing Date: 2001-06-19
Classification: D21B,D21C,D21F,Y02W,Y10S

Abstract:
A method of separating cellulosic fines and cellulosic fibres from an aqueous suspension which contains cellulosic fibres, cellulosic fines and hydrophobic materials, comprisingA) screening the aqueous suspension to remove cellulosic fibres and to provide a filtrate thenB) subjecting the filtrate to a dispersed air flotation stage in the presence of calcium ion in an amount of at least 50 ppm and at a pH of at least 6 thereby forming an upper Reject fraction and a lower Accept fraction whereby cellulosic fines concentrate in the Accept fraction and hydrophobic material concentrates in the Reject fraction andC) separating the Reject and Accept fractions.