EFFECT OF AGING ON DEINKING OF OLD NEWS PRINTS

Abstract

To investigate the effect of aging on deinking of old newsprint the process conditions were fixed for all the trials. The waste paper to be recovered was taken as a mixture of 70% old newspaper and 30% old magazine grade paper. Deinking process used in recovery was chemical deinking under alkali conditions. The optical properties and the mechanical properties were observed with aging. Effluent from each stage was observed with aging to support the evident that fiber degradation takes place with aging. The impact of aging on ink particles and the process performances were also observed. It was found that the aging has negative impact on all the mechanical and optical properties. The bound ink content is increased with aging and the average size of ink particles too. Therefore the ink detachment and ink removal processes were also affected by aging. The residual ink content can be decreased by changing process conditions and this will also result in less chemical requirement for further bleaching process.