The effect of alkali charge on Bambusa vulgaris Schrad. ex J.C. Wendl., for the kraft pulping process

摘要

The objective of this study was to evaluate the effect of the alkali charge on Bambusa vulgaris Schrad. ex J.C. Wendl. with two years old from commercial plantings in Brazil, on kraft pulping process under different alkali charges determining the pulp conditions to bleachable and unbleachable pulp. The alkali charges applied varied from 10 to 24%, at 2 points of interval. The parameters analyzed were: total yield, rejects content, screened yield, kappa number, viscosity, residual active alkali and hexenuronic acids content. For the total yield the values varied from 34.6 to 52.2%. For the screened yield the values varied from 34.6 to 51.2%. The rejects content was low for all alkali charges being almost zero from 14% of active alkali. For the kappa number the values varied from 80.8 to 8.8. For the viscosity the values varied from 57.3 to 19.1 cP. For charges 10-12% the residual active alkali was zero, it shows that alkali was not sufficient in cooking, and between 14 and 24% the values varied from 1.9 to 13.0 g/I. The residual active alkali and hexenuronic acids content increased with increasing alkali charges. The active alkali charge for unblanchable pulp was 14% and for blanchable pulp was 16%.