OPTIMIZATION OF AN ALKALINE PEROXIDE INTERSTAGE TREATMENT OF JACK PINE (PINUS-BANKSIANA LAMB) USING A D-OPTIMAL DESIGN

For many decades, the utilization of jack pine in the pulp and paper i ndustry has attracted considerable interest but without any major brea kthrough. However, in the past few years the emergence of new technolo gies has provided hope for its potential use. One of these technologie s consists in the addition of hydrogen peroxide within the thermomecha nical pulping process. To study the influence of numerous process para meters on the interstage treatment of jack pine and to optimize this c omplex process, a D-optimal experimental design was conducted. A total of 7 variables were considered. It was found that to maximize the pro perties of the fibres and the resulting paper, a temperature of 115 de grees C with a narrow plate gap at the first refining stage and a high consistency at the second stage had to prevail. A sodium hydroxide tr eatment radically improved the fibre bonding properties without affect ing the tear strength but at the expense of a loss of 4,6 points in IS O brightness. Validation trials allow to draw some conclusions on the advantages and shortcomings of this type of experimental design. This design is efficient, provided sufficient information is available to t arget likely interactions. Otherwise, a screening design would be requ ired thus increasing the total cost of the study.