Laboratory Study to Evaluate Methods for Deinking Water-Based Flexographic Printing ONP, 2007 TAPPI 8th Research Forum on Recycling

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A few noticeable studies have helped our understanding of deinking wastepaper that contains flexographic newsprint. Some proposed method of deinking wastepaper with flexographic newsprint, includes; a two stage deinking process. In which, the first stage is a done in a non-alkaline environment and the second stage is an alkaline treatment. Another method describe as the organically modified clay removal of ink, involves reacting ammonium salt to cation-exchangeable clay. The organoclay acts as a collector for flexographic ink. Yet another method which used direct electric field incorporated into flotation reported improvement in brightness and speck count.

Besides flotation, washing has been used to treat wastepaper with flexographic newsprint. Washing could be used by itself or combination with flotation. One drawback for washing is it has yield loss and the subsequent costly treatment involving the clarifiers. Comparing the relative importance of all these methods could be difficult considering the type and composition of furnish used in each study are different, the type of flexographic newsprint, the pulp sample preparation method employed and the lack of yield loss analysis data. A laboratory study was carried out to evaluate some of these methods to determine which method offers the best solution to flexographic ink. This study was focused on the flotation process only.