MEASUREMENT OF DEINKED PULP QUALITY AND DEINKING EFFICIENCY, PART II - IMPACT OF SPECIMEN PREPARATION PROCEDURES ON INK CONTENT RESULTS - SHOWS THE IMPORTANCE OF SPECIFYING LAB METHODS WHEN REPORTING RECYCLED PULP QUALITY RESULTS

Several specimen preparation procedures were reviewed and experimental results obtained from these procedures were compared. In this second part of a series, differences between the procedures and their effect on inked area and ink removal efficiency were presented. ONP/OMG and M OW pulp samples were collected from the feed and the accept of a pilot plant flotation column. The different variables evaluated within each laboratory method for specimen preparation include pulp suspension pH , water quality and specimen type. A statistical analysis of the resul ts was performed in order to determine the significant differences bet ween the specimen types It was shown that 4.0g Buchner pads generally show the highest ink content when compared to handsheets. The use of a lum and polyacrylamide in the preparation chemistry of 4.0g pads yield the lowest wire-blotter differences in 180 brightness. Alum also show s the lowest ink content. No given pad preparation chemistry stood out as the best in terms of ink retention. In the preparation of millipor e membrane samples for sub-visible ink image analysis, the use of sulp huric acid offers the highest ink retention. A setting of 1100 rpm of the dynamic drainage jar yields the optimum number of particles. In su mmary, a standard specimen preparation procedure to be widely used wit hin this industry can only be elaborated and defined in respect to a s et of agreed upon end product quality criteria.