The potential of ultrasound assisted deinking, 2010 TAPPI PEERS Conference

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Rapid developments in printing technology as well as increasing demands in de-inked pulp quality require adequate responses from deinking technology.

The paper presents results of a project which studied the potential of high power ultrasound treatment to remove printing inks from fibre surfaces. The majority of earlier studies in the field had been carried with less powerful equipment and mainly focussed on the effects on selected printing inks. No conclusions, therefore, can be drawn for what might be expected for mixtures of printed products containing a much broader spectrum of printing inks.

Based on a comprehensive literature survey and on a number of lab trials findings reported in literature were confirmed as far as toner-based prints are concerned. Ultrasound obviously enhances the detachment of ink par-ticles from fibres as well as their break up into an easier to float size spectrum. De-inked pulp brightnesses were superior compared to those obtained with conventional methods - even without any addition of chemicals and also at consistencies as high as 2%.

Although there are still a large number of open questions to be answered before US supported de-inking might become an economic industrial reality, the objective seems to be worth to be further pursued.