Reduction of flotation losses, Part 2: Detrimental effect of released surfactants on flotation efficiency - Removing surface-active substances leads to better selectivity

In flotation deinking, variations in froth stability over time have come tu be known as a major cause of flotation loss. The influence on froth suabili ty of tensioactive material dissolved in the process waters was studied. Dynamic surface tension measurements on an industrial deinking line showed that low surface tension-values were caused by the presence of tensioactive elements concentrated in froth during the flotation process. Differences i n froth generated by waters coming froth rotogravure and from offset OMG, t raced the origins of variations fn froth stability, back to raw materials. In rotogravure OMG, the direct influence on flotation efficiency of tensioa ctive elements released from recovered papers, was proven. An important red uction in these losses was obtained with removal of the tensioactive elemen ts present in repulping waters.