ALKALINE-PEROXIDE INTER-STAGE TREATED MECHANICAL PULP FROM JACK PINE (PINUS-BANKSIANA) .2. PULP OPTICAL-PROPERTIES, COLOR REVERSION, EXTRACTIVES CONTENT, AND PROCESS IMPLICATIONS

The objective of the study was to facilitate the use of jack pine mech anical pulps. Typically, this species has a high specific energy consu mption, poor strength properties, brightness reversion and pitch probl ems because of the intrinsic wood properties. Pilot-scale TMP and AP-T MP were produced from jack pine (Pinus banksiana) and black spruce (Pi cea mariana). In the previous part of this study (Part I.), the influe nce of alkaline-peroxide inter-stage treatment on pulp energy consumpt ion and physical properties was shown. In this part (Part II.) the eff ects of the above treatment on pulp optical properties, color reversio n, and extractives removal were determined. At constant specific energ y consumption, spruce AP-TMP gave superior brightness over all pulps. With the use of alkaline-peroxide treatment the high original extracti ves content of jack pine chips was reduced to a very low level, being comparable to that of spruce mechanical pulps. The tendency for yellow coloration of jack pine mechanical pulps was slightly reduced. Finall y, a simple process implication for the existing baseline TMP process is given.