Estudos de qualidade da madeira de Eucalyptus globulus Labill. para producao de pastas para papel e da utilizacao do processo nao convencional ASAM

The wood quality of Eucalyptus globulus Labill. trees grown under different growth conditions, spacing and provenances and kraft pulping. Pulping experiments were made using ASAM and kraft processes and reaction kinetics were studied. The wood basic density varied with tree age, growth conditions, spacing, provenances and site, with in the range 450-600kg/m"3. There was also variation in fibre length, diameter and wall thickness. The tree age was the most important factor (0.69 and 1.06 mm at 2 and 18 years of age, respectively). Fibre wall thickness ranged 5.49-6.56#mu#m. The average wood composition ranged as follows: ash 0.2-2.2% total extractives 3.7-9.4% lignin 25.7-29.8%, glucose 42.8-50.0% and xylose 17.4-23.9%. Kraft pulping yield ranged 51.0-57.4% with Kappa numbers 15.6-20.2. The yield for ASAM pulping ranged 59.7-56.6% with Kappa number 12.8-21.7. The wood of Eucalyptus globulus trees grown in the different conditions had an adequate quality as a raw-material for pulp production. ASAM pulping may be used eucalypt wood with favourable Kappa numberAvailable from Fundacao para a Ciencia e a Tecnologia, Servico de Informacao e Documentacao, Av. D. Carlos I, 126, 1249-074 Lisboa, Portugal / FCT - Fundação para o Ciência e a TecnologiaSIGLEPTPortuga