Removal of Stickies and Electrostatic Inks Using Flotation Process

Developing techniques for successfully recycling office wastepaper has become more and more important due to government regulations requiring post-consumer content in printing and writing grades of paper, increased consumer awareness on paper recycling and the limited supply of deinking grade wastepaper available. Office wastepaper remains an underutilized source of woodfree post-consumer waste due primarily to its heavy contamination with stickies and electrostatic printed inks. Removal of these contaminants by flotation remains a challenge due to the chemical and physical differences of these contaminants when compared with conventional inks. Modification of the interfacial properties of these contaminants is imperative to make flotation a viable process for treating office wastes. There are certain limitations as to what one can do to improve the performance of the displector type of surfactants through modifications of their structure. PPG Industries, Inc. has developed a series of unique surface modifying agents that selectively adsorb onto and modify the surface properties of stickies and electrostatic ink particles and hence enhance the floatability of these contaminants. Results from both laboratory evaluations and plant trials will be presented.