FREMGANGSMAATE OG ANORDNING FOR AVSVERTING AV RESIRKULERT PAPIRMASSE.

摘要

Deinking of paper having print during the production of recycled paper is accomplished by using a flotation column (15) . A finely comminuted fibrous suspension having a consistency of 2-8% is introduced into a first vertical column (30) to flow downwardly. The suspension passes through a sharp-edge orifice (38) and just below the orifice air (substantially atmospheric or pressurized) is sucked into the suspension and entrained in it. This forms a downwardly moving foam bed. The suspension with entrained air passes from the open bottom (32) of the first column into a second column (33) to form a suspension/froth interface (46) in the second column. Ink particles in the suspension attach to the air bubbles and are entrained in the froth (47). The froth with entrained ink particles is removed from the top (at 50) of the second column and a suspension substantially free of ink particles is removed from the bottom (36) of the second column, and is preferably deaerated (with 52). The sharp edge orifice is preferably circular in configuration with about a 1/2 - 2 inch diameter (39).