Development of a methodology to predict sticky deposits due to dissolved and colloidal material destabilization in papermaking - Application to different systems

Abstract

Due to trends in papermaking like closed water systems or higher use of recovered paper as raw material, a large number of contaminants are accumulated in the system as dissolved and colloidal material (DCM). When the DCM is destabilized by a sudden change in the system conditions, it produces sticky deposits called secondary stickies that affect the papermaking processes and the quality of the final product. The laboratory methods existing to predict DCM destabilisation have limitations as low reproducibility or they do not distinguish between sticky and non-sticky materials and/or high volumes are necessary to perform the test, etc. In order to solve these problems, a methodology to predict the depositability potential of DCM has been developed by the Complutense University of Madrid. The methodology is based, first, on the destabilisation of the DCM by polymer addition, second, on its deposition on the collector surfaces and, third, on the quantification of the formed deposits by image analysis. Results show that the methodology has a good reproducibility with an error below 10%. Validation was carried out by application of the method to different cases. Results demonstrate that the developed methodology is a useful tool for researchers and papermakers to predict deposit problems due to the destabilisation of DCM in papermaking.