Stickies removal in a deinking line of a newsprint mill: efficiency of the different process stages

The study evaluates stickies removal efficiency of the different process stages in a deinking line of a newsprint paper mill, using 100% recovered paper as raw material. Two different situations have been considered, namely, a normal one, with a low level of stickies at the beginning of the line, and a critical situation with a high level of stickies. Removal efficiencies have been compared with data available in the literature. Although results show a high efficiency of the process for contaminants removal in both cases (80-90%), residual stickies levels at the end of the line are very different (a double initial stickies content causes four times higher stickies content at the end of the line). The first loop is the most critical step, removing 72% of the inlet stickies to the line. The most efficient units are preflotation and the second thickening stage (disc filter 2).