New automated method for macrocontaminant analysis: Industrial applications

In recycled paper processes, stickies are the origin of many production disturbances. In this paper, we present how the recently developed method for macrocontaminant analysis was used with industrial samples for process analysis. The new automated stickies measurement method allows (i) determination of the threedimensional (3D) morphology of screened particles (without any deformation) and (ii) classification of the particles as stickies among contaminants. This is achieved by a combination of laser triangulation and local near-infrared spectroscopy (NIR). Measurement of macrocontaminants in pulp samples and their classification allow meaningful evaluation of their specific removal. Chemical nature and amount of the macrocontaminants coming from different raw materials were studied and were shown to be very different in two different mills. In an Asian mill, a low removal of pressuresensitive adhesives (PSAs) in the process (46%) was found in comparison with high removal of other stickies (99%). Applications of this device are shown, while the new on-line sensor for macrocontaminant analysis is being developed.