Alkaline-peroxide inter-stage treated mechanical pulp from jack pine (Pinus banksiana) .1. Introduction and pulp physical properties

Pilot-scale TMP and AP-TMP were produced from jack pine (Pinus banksiana) and black spruce (Picea mariana). The objective of the study was to facilitate the use of jack pine mechanical pulps. Typically, this species has a high specific energy consumption; poor strength properties, brightness reversion and pitch problems due to the intrinsic wood properties. In this part of the study (Part 1), the effect of alkaline-peroxide inter-stage treatment on pulp energy consumption and physical properties was determined. At constant specific energy consumption, spruce AP-TMP gave superior strength properties over all pulps. To reach a given freeness,jack pine AP-TMP used somewhat less refining energy than jack pine TMP, but there was no considerable increase in pulp strength properties. In Part 2, the effects of the above treatment on pulp optical properties, color reversion, and extractives removal are shown.