Flotation Deinking Studies of Old Newspapers and Magazines, 2000 Pulping / Process & Product Quality Conference Proceedings

J. K. Borchardt, T. J. Schroeder, F. Shieh--In addition to deinked pulp brightness, other important newspaper and newspaper/magazine deinking surfactant properties include flotation stage yield loss and surface properties of sheets made from deinked pulp. As part of a study aimed at developing flotation deinking surfactants providing improved brightness, lower pulp yield loss and improved sheet surface properties, laboratory and pilot plant results will be reported for three flotation deinking surfactants of substantially different chemistries.

Laboratory studies include models of three U.S. West Coast newspaper deinking mills using flotation as a primary deinking step. One is a wash - flotation - wash process and the other two a more conventional flotation - wash deinking process. The furnish and process conditions in these three studies differed significantly.

Laboratory results indicate two flotation deinking agents of different novel chemistries provided superior deinking performance compared to a commercial flotation deinking agent. The deinking agents of novel structure provided lower yield loss at equivalent brightness compared to the commercial deinking agent.