A 10-DAY MILL TRIAL OF NEAR-NEUTRAL SULPHITE DEINKING. PART Ⅰ: DEINKED PULP OPTICAL AND PHYSICAL PROPERTIES

摘要

In April 2002, a problem-free, 30-hour mill trial of near-neutral sulphite deinking produced a final DIP having optical properties similar to the ones of conventional DIP. However, this trial was too short to assess the local and global long-term impacts of sulphite on the mill. Thus, a 10-day trial was run in February 2003. This report, the first one in a series of three, focuses on the DIP optical and physical properties. The second and third reports will concentrate on the recycle plant and on the balance of the mill, respectively. In summary, the 10-day trial supported the deinking performance data from the 30-hour trial: the final DIP produced during this near-neutral sulphite deinking trial had an average ERIC of 140 and an average ISO brightness of 58.6%, values similar to those of the conventional DIP. In addition, when compared to standard DIP, the following statistically significant changes (95% confidence level) to the sulphite DIP were observed: increase in opacity, burst index and breaking length, and decrease in CSF and tear index. There was no statistically significant change in stretch, TEA, bulk, and fibre length. Thus, a switch to sulphite chemistry should maintain or improve the DIP quality, while resulting in a substantial deinking chemical cost saving (between $5 and $ 10 per tonne of DIP). A one year trial has been completed as of July 15, 2004.