Effect of alkyl chain in alcohol deinking of recycled fibers by flotation process

Abstract

The deinking of various types of newspapers has been necessitated by governmental regulations as well as increasing public interest in recycling paper taken from our natural environment. The increasing volume of newspaper makes it an important class of paper available for deinking. In this study, the effect of number of carbon atoms in alkyl chain of a simple deinking agent using different alcohols was developed. Four-step process involving pulping, washing, froth flotation, and another washing with a number of alcohols in pulping and flotation stages was employed. Conventional laboratory-scale flotation cell was used to study ink removal from pulp slurries obtained from water-based flexographic newsprint. Hydrodynamics conditions were constant and other chemicals dosages were chosen the same as optimum values cited in literatures. We report the brightness and intensity of ink spot of handsheets formed of deinked fibers as deinking efficiencies. Application of alcohols with any alkyl chain instead of hydrogen peroxide in flotation stage gives higher brightness. The highest brightness was achieved in the case of totally hydrogen peroxide free using alcohol in pulping and flotation stages. The brightness of final pulp increases with the number of carbon atoms in alkyl chain (C 1–C 7). Low concentration of deinking agent makes this combination of chemicals economical and environmental friendly.