Alkaline sulfite - Anthraquinone - Methanol (ASAM) pulping of corn stalks

Corn stalks pulping was performed by both ASAM and kraft processes. Increasing of either alkali charge or methanol in the cooking liquor increased delignification and decreased pulp yield. Under optimum pulping conditions, the ASAM process produced an about 5% higher pulp yield than the kraft one, at an almost similar kappa number. The strength properties of the ASAM pulp increased up to a certain limit of the chemical charge, then decreased. Both bleached and unbleached ASAM pulps exhibited higher viscosity and brightness than the kraft pulps. Following total chlorine free (TCF) or elemental chlorine free (ECF) bleaching, tensile, tear and burst strengths were about 10% higher than for kraft pulp counterpart.