HYDROCYCLONE DEINKING AND REMOVAL OF STICKY CONTAMINANTS DURING PAPER RECYCLING

摘要

The removal of sticky contaminants and/or ink particles during the production of recycled paper is accomplished utilizing a hydrocyclone (31) froth flotation process. Paper having sticky contaminants from labels, tapes, hot melts, and other tacky substances, and/or print, is reduced to a finely comminuted liquid solids suspension of about 1-4% consistency (preferably over 2%). The suspension is introduced into a first end (44) of a vortex (41) in a hydrocyclone (31), and the air is sparged radially inwardly into the suspension vortex by passing it through a porous inner wall (47) of the hydrocyclone. Lighter weight sticky contaminants move to the center of the hydrocyclone, facilitated by the radially inward movement of the sparging air, and hydrophobic sticky contaminants and/or ink particles attach to the air bubbles and form a foam. The foam and lightweight sticky contaminants are removed from the first end (at 33, thru 51) of the vortex, while the pulp which has had sticky contaminants and/or ink removed therefrom is discharged from the second end of the vortex (at 32), opposite the first end. A plurality of vertical axis hydrocyclones (21) may be connected together in series, with a plurality of the series connected in parallel, to provide the most effective treatment. Removal of sticky contaminants can be practiced prior to or simultaneously with deinking (Figure 3). IMAGE