Control of Potential Secondary Stickies in Deinked Pulp, 2003 Fall Technical Conference

Secondary stickies are formed in recycled fiber pulp when conditions of a process stream change. Part of the secondary stickies material may stay in dissolved or colloidal form and turn into solid phase later in the process when process conditions change. This dissolved and colloidal material is called potential secondary stickies. These detrimental substances can be controlled by either removing them e.g. by internal water treatment or by fixing them to pulp and removing them from the system with the final product. By both of these actions, the harms caused by secondary stickies at the paper machine may be reduced.

A new simple method for measuring the amount of dissolved and colloidal matter, called potential secondary stickies, was used in this study to measure the quality of process water and recycled fiber pulp water phase. The measuring method was used to evaluate the purification result of laboratory precipitations and pilot dissolved air flotation (DAF) treating deinked pulp filtrates with different coagulation and flocculation chemicals. Interactions between wood pitch in thermomechanical pulp (TMP) and stickies in deinked pulp (DIP) were studied in laboratory scale, and attachment of colloidal wood pitch onto the DIP fibers was observed.