Reduction of flotation losses, Part 1: Is there something interesting to recover in flotation deinking froths? Making a case for incorporating more fines and filler into paper

When deinking mixtures of newsprint and magazine, the main task is to remov e as as possible of the almost 2% of ink which was applietl on the paper du ring printing. Compared to this 2%, the amount of flotation losses in the i ndustry ranges between 5% and 20%, depending on the raw materials. Losses a re thus much larger than the amount of ink applied to paper. The C.T.P. was asked by French papermakers to make an in-depth study of the phenomena involved in flotation in order to tip to reduce these losses. Se veral directions were investigated. First of all, a survey was performed in order to study the average characteristics of industrial deinking froths i n tel-ms of fibres, fines and filler content as well as in terms of cleanli ness of these components. These results are presented hereafter; illustrati ng well the possibilities to reduced flotation losses. A second part will focus on dynamic interfacial tension measurements during flotation with characterization of surfactant removal and surfactant relea se from recovered paper.