DETERMINATION OF FACTORS INFLUENCING GRANULATE-ASSISTED DISPERSION OF RECYCLED PULP BY INVESTIGATING OPERATING CONDITIONS

Abstract

In the recent years, ink removal from recovered paper has gained major focus primarily due to environmental and economic reasons. There is hardly any further scope of improvement in the existing techniques in the form of quality, energy efficiency, ceo-friendly and yield, which meets the everlasting demands of industry and consumer. Consequently, there is a pressing need of new technique to meet these criteria. Recently, a new methodology has been developed at Technical University, Dresden, to remove ink particles by the use of polymeric beads during pulping which is termed as "Adsorption Deinking". In contrast to conventional washing and flotation deinking method, adsorption deinking technique is more energy-efficient in which small detached ink particles gets adsorbed on to the small plastic granules - adsorbent material. These plastic granules are added during pulping process eliminating one step for removing ink particles. Also, this adsorbent material in pulping vessel leads to mechanical-rubbing action due to the relative motion between plastic granules and paper pulp which is similar to low speed dispersing (kneading) of specks-ink particles. Dispersion of specks is one of the most energy intensive sub-processes in paper recycling of recovered waste paper but these sub-processes can possibly be combined into just one step of pulping. This new alternative dispersion technique is christened by 'Granule-assisted dispersion'. Before implementation of this new process, optimization must be carried out for granuleassisted dispersion. Conventional dispersion strongly depends on parameters like temperature, consistency and intensity of mechanical force applied on pulp fibres. In the following thesis work these three parameters are varied to see the effect on alternative dispersion. Effect of changing these parameters on fibres morphology is also to be measured to check whether this new technique results in similar quality of paper. From each parameter best outcomes are chosen for final trial to give the optimum result of alternative granule-assisted dispersion.