IMPROVING ADSORPTION DEINKING BY IDENTIFYING THE OPTIMUM BALANCE BETWEEN SURFACE PROPERTIES OF POLYMER BEADS AND DEINKING CHEMISTRY

Abstract

From the last 50 years, ink removal from recovered papers has become a very important technology in paper and board recycling. The deinking processes used so far have made obvious contributions to secure the raw material basis of the paper and board industry. In contrast to the flotation deinking process in which small air bubbles are used as ink collectors, the novel and more energy-efficient adsorption deinking technique depends on the attachment and adsorption of ink particles on small polymer beads. Adsorption deinking allows implementation of three sub-processes; pulping, dispersion and deinking in single step. The energy savings of adsorption deinking results from the fact that the process can be performed at higher stock consistencies and thus allows to save large amount of water. The present investigation was carried out to improve adsorption deinking by finding the optimum balance of the deinking chemistry and the types of polymer beads. Different types of deinking recipes and polymer beads were used for this study and the corresponding results are discussed in this dissertation. Also adsorption deinking trails with different amount of calcium ions were performed and the results are discussed. Different types of print products were tried with different chemical recipes and types of polymer beads. Subsequent flotation deinking and Undeinked trials were also performed for the comparison of results. There is a strong influence of calcium ions on adsorption of ink particles on the polymer beads. It was found that EGA 3000 recipe works perfectly well for newspapers and it gives a very low dirt specks area comparatively. Polyethylene terephthalate bead gives the highest brightness and the lowest dirt specks area when tried with newspapers and INGEDE recipe.