Analysis of deposits/stickies from newsprint mills using recycled fibre

A general scheme has been devised for the analysis of deposits from newsprint mills using recycled fibre. The scheme consists of sequential solvent extraction of a deposit, followed by analysis of the extracted and non-extracted fractions by various techniques. Eleven samples of deposits were collected from forming fabrics and press sections of five mills, and from our pilot plant paper machine. Detailed analysis was conducted only on press section deposits. In addition to polymeric materials, which are conventionally associated with ''stickies'', the deposits contained significant amounts of inorganics as well as organic compounds originating from deinking chemicals, ink residues and wood resin, all of which could play an active role in initiating or enhancing deposition.