Full characterization of stickies in a newsprint mill:: the need for a complementary approach

To ensure paper machine runnability, trouble-free converting, and high quality products, stickies must be removed during stock preparation of recycled pulp. However, the stickies removal efficiency along the process is not easy to assess since there are many different types of stickies that have to be considered in a mill stickies audit. Total stickies, macro-stickies, micro-stickies, and secondary stickies are quantified by different methods. Macro-stickies allow us to monitor the removal efficiency of the process while micro-stickies and secondary stickies predict the deposition potential of the pulp under different conditions. Micro-stickies predict calcium-soap deposits and secondary stickies predict the destabilization of the dissolved and colloidal material. Cationic demand only predicts a certain type of stickies. Therefore, integrated approach for the full characterization of stickies throughout the papermaking process is necessary. Application: The full characterization of stickies along the process allows papermakers to identify contaminants and to improve stickies control in the mills.