Evaluation and Optimization of Old Magzines Deinking Process of a Modified Lignin Sulfonates Deinking Agent

摘要

Deinking is an important process in waste paper recycling process,and this study mainly focuses on the properties of the deinking agent and process optimization.DIA-30 prepared in our laboratory,and FS and LD,were the three representative deinking agents studied herein.Brightness,effective residual ink concentration (ERIC),dirt,macro-stickies,fiber loss during repulping,flotation,and washing processes were measured to evaluate the performance of the deinking agents and optimize process conditions.Each of the deinking agents exhibited different advantages:DIA-30 was optimal for deinking efficiency,brightness enhancement,as well as dirt and macrostickies removal,whereas LD was optimal for ink removal during flotation process but performed poorly in terms of brightness enhancement.FS showed a relatively balanced performance compared to those of DIA-30 and LD in the deinking process,but DIA-30 is the best option for deinking due to its outstanding comprehensive properties.The optimal repulping conditions for the deinking of 100％ old magzines (OMG) using DIA-30 are as follows:repulping temperature,60℃;pulp consistency,13 wt％;repulping time,20 min;n2O2 dosage,0.5 wt％ (oven-dried pulp);NaOH dosage,1.2 wt％ (oven-dried pulp);Na2SiO3 dosage,0.3 wt％ (oven-dried pulp);and optimum DIA-30 dosage,0.1 wt％.